1. A contact lens package, comprising: a cavity; a cast molded contact lens disposed in the cavity, wherein the contact lens comprises a reaction product of a polymerizable composition comprising polyvinyl pyrrolidone, at least one hydrophilic monomer, and at least one cross-linking monomer reactive with the at least one hydrophilic monomer; a surfactant-free liquid disposed in the cavity and in contact with the contact lens, the liquid including polyvinyl pyrrolidone; and a seal surrounding the cavity to maintain the contact lens in a sterile environment.

2. The package of claim 1, wherein the contact lens is a hydrogel-containing contact lens.

3. The package of claim 1, wherein the contact lens includes a hydrophilic polymeric material and the polyvinyl pyrrolidone is present in the contact lens in an amount of about 1% to about 50% by weight of the hydrophilic polymeric material.

4. The package of claim 1, wherein the contact lens includes a hydrophilic polymeric material and the polyvinyl pyrrolidone is present in the contact lens in an amount of about 5% to about 40% by weight of the hydrophilic polymeric material.

5. The package of claim 1, wherein the contact lens includes a hydrophilic polymeric material and the polyvinyl pyrrolidone is present in the contact lens in an amount of about 10% to about 30% by weight of the hydrophilic polymeric material.

6. The package of claim 1, wherein the contact lens comprises at least two water soluble polymers.

7. The package of claim 6, wherein one of the water soluble polymers is polyethylene glycol.

8. The package of claim 1, Therein the liquid is an aqueous liquid.

9. The package of claim 1, wherein the liquid comprises a saline solution.

10. The package of claim 1, wherein the liquid comprises a buffered saline solution.

11. The package of claim 1, wherein the package is sterilized.

12. The package of claim 1, wherein the contact lens is a single use contact lens.

13. The package of claim 1, wherein the contact lens comprises a hydrophilic polymer including at least one monomer selected from the group consisting of hydroxalkyl acrylates, hydroxyalkyl methacrylates, N-vinyl pyrrolidone, acrylamides, vinyl alcohol, hydrophilic polyurethane precursors, glycerol acrylates, glycerol methacrylates, acrylates methacrylates, and mixtures thereof.

14. A contact lens package, comprising: a cavity; a cast molded contact lens disposed in the cavity, wherein the contact lens comprises a reaction product of a polyrmerizable composition comprising polyvinyl pyrrolidone and at least one monomer; a liquid disposed in the cavity and in contact with the contact lens, the liquid including polyvinyl pyrrolidone in an amount effective in reducing migration of the polyvinyl pyrrolidone present in the contact lens from the contact lens into the liquid in the cavity; and a seal surrounding the cavity to maintain the contact lens in a sterile environment.
Contact Lens Description
FIELD

The present invention relates to hydrogel-containing contact lenses, packaging systems including same and methods of producing same. More particularly the invention relates to hydrogel-containing contact lenses, for example, disposable contact lenses, including water soluble polymer components, and packaging systems for use with same and methods of producing same.

BACKGROUND

In the recent past, a method for producing hydrogel-containing contact lenses has been developed which is more economical than either lathe cutting or spin casting, and provides better control over the final shape of the hydrated lens. This method involves direct molding of a monomer mixture wherein said mixture is dissolved in a non-aqueous, displaceable solvent. The mixture is placed in a mold having the precise shape of the final desired hydrogel (i.e., water-swollen) lens, and the monomer/solvent mixture is subjected to conditions whereby the monomer(s) polymerize, to thereby produce a polymer/solvent mixture in the shape of the final desired hydrogel lens.

After the polymerization is complete, the solvent is displaced with water to produce a hydrated lens whose final size and shape are quite similar to the size and shape of the original molded polymer/solvent article.

Such direct molding of hydrogel contact lenses is disclosed in Larsen, U.S. Pat. No. 4,495,313 and in Larsen et al., U.S. Pat. Nos. 4,680,336, 4,889,664 and 5,039,459. In addition, other patents to be considered include Larson U.S. Pat. No. 4,565,348; Okkada et al U.S. Pat. No. 4,347,198; Shepherd U.S. Pat. No. 4,208,364; Mueller et al EP-A-0493,320A2; and Wichterle et al U.S. Pat. No. RE 27,401 (U.S. Pat. No. 3,220,960). The disclosure of each of these patents is incorporated in its entirety herein by reference.

It would be advantageous to provide new and beneficial hydrogel-containing contact lenses, packaging systems for such lenses and methods of producing such contact lenses.

SUMMARY

New hydrogel-containing contact lenses, packaging systems for use with such lenses and methods of producing such lenses have been discovered. The present hydrogel-containing lenses take advantage of the economies and shape control benefits of direct molding of hydrogel-containing contact lenses. In addition, by properly selecting the diluent or material included in the mold during lens formation, in particular by employing one or more water soluble polymer components, such diluent or material may remain within the lens ready for use in an eye. Thus, the present methods of making hydrogel-containing contact lenses are even less complex and more economical, for example, by eliminating the solvent displacing step, relative to prior art direct molding processes discussed elsewhere herein. The present packaging systems advantageously maintain the diluent or material in the contact lenses prior to use in an eye. In addition, the hydrogel-containing lenses advantageously have increased modulus or strength when first placed in an eye. Over time, for example, over a one day use period, the diluent or material is removed from the lens and replaced by water or tear fluid in the eye. When the lens is removed from the eye, it has less strength and provides an indication to the wearer that the lens should be disposed of and replaced. In addition, should the wearer use the lens again, the lens would be less comfortable to wear, for example, due to the loss of the diluent or material. This reduced comfort feature provides an indication to the wearer that the lens should be disposed of and replaced. The present lenses are particularly advantageous when provided as disposable lenses, for example, lenses suitable or structured for one time usage.

In one broad aspect, the present invention is directed to contact lenses which comprise contact lens bodies. The contact lens bodies comprise a hydrophilic polymeric material and a water soluble polymer component (WSPC). Such contact lens bodies are ready for use in an eye. In one embodiment, the WSPC is in intimate admixture with the hydrophilic polymeric material.

In a very useful embodiment, the WSPC is derived from a diluent material used during polymerization of the hydrophilic polymeric material. The WSPC advantageously is derived from a diluent material, for example, is at least a portion of the diluent material, used during solution polymerization of a hydrophilic polymeric material.

In one embodiment, the contact lens body is produced using wet cast molding.

As noted above, the present contact lenses advantageously are structured to be disposed of after a single use in the eye.

The present contact lens bodies including the WSPCs preferably have increased modulus relative to identical lens bodies in which the WSPC is replaced with water.

The WSPC advantageously is physically immobilized by the hydrophilic polymeric material in the present contact lens bodies. For example, the WSPC and the hydrophilic polymeric material may form an interpenetrating network or a pseudo interpenetrating network, preferably a pseudo interpenetrating network, in the lens body.

The present contact lens bodies preferably are configured or structured so that at least a portion of the WSPC leaves or is removed from the contact lens body during use of the contact lens body in an eye.

The hydrophilic polymeric material preferably is obtained by polymerization of at least one monomeric component, for example, by the polymerization of at least one hydrophilic monomeric component and at least one cross-linking monomeric component.

The hydrophilic monomeric component may be selected from any suitable such component. In a very useful embodiment, the hydrophilic monomeric component is selected from hydroxyalkyl acrylates, hydroxyalkyl methacrylates, N-vinyl pyrrolidone, acrylamides, vinyl alcohol, hydrophilic polyurethane precursors, glycerol acrylates, glycerol methacrylates, acrylates, methacrylates, substituted counterparts thereof and the like and mixtures thereof.

As used herein, the term “substituted counterparts thereof” refers to entities, e.g., compounds, which include one or more substituents and are effective to function in the present invention substantially like the unsubstituted entities, for example, the compounds listed herein.

Any suitable WSPC may be employed provided that it is effective in the present contact lenses, as described herein.

In one embodiment, the monomeric components from which the WSPCs are derived, for example, at least one ethylenically unsaturated hydrophilic monomeric component, are polymerizable to form linear or branched chain water soluble polymers or copolymers.

Hydrophilic monomeric components suitable for production of the WSPCs include, but are not limited to, hydrophilic vinylic monomers, such as vinyl (C.sub.4-C.sub.45)alkyl ethers, vinyl (C.sub.7-C.sub.49) alkenoic acids and the like and mixtures thereof; hydroxy substituted (C.sub.5-C.sub.45)alkyl, alkoxy-alkyl and polyalkoxy-alkyl and mono- or bi-cycloaliphatic fumarates, maleates, acrylates, methacrylates, acrylamides and methacrylamides, and the like and mixtures thereof; acrylic acid, methacrylic acid, the corresponding amino or mono- and di-(lower alkyl)amino substituted acrylic monomers and the like and mixtures thereof; and vinyl-lactams and the like and mixtures thereof. Typical monomers include, but are not limited to, 2-hydroxyethyl, 2-hydroxypropyl, and 3-hydroxypropyl acrylates and methacrylates; N-vinylpyrrolidone; N,N-dimethylaminoethyl methacrylate; methoxyethyl-, ethoxyethyl, methoxy-ethoxyethyl and ethoxy-ethoxyethyl acrylates and methacrylates; (meth)acrylamides like N,N-dimethyl, N,N-diethyl, 2-hydroxyethyl-, 2-hydroxypropyl-, and 3-hydroxypropyl acrylamides and methacrylamides; vinyl sulfonic acid; styrene sulfonic acid; 2-methacrylamide-2-methyl propane-sulfonic acid and the like and mixtures thereof.

In one embodiment, the WSPC preferably includes units derived from one or more of acrylic acid, hydrophilic derivatives of acrylic acid, methacrylic acid, hydrophilic derivatives of methacrylic acid, cationic/anionic pairs of monomeric components, cationic monomeric components, anionic monomeric components, nonionic monomeric components, hydrophilic vinylic monomeric components, salts thereof and mixtures thereof.

In one very useful embodiment, the WSPC is selected from polyalkylene glycols, for example, polyethylene glycols, polypropylene glycols and the like, polyvinyl pyrrolidone, polymethacrylic acid, polyvinyl alcohol, and the like and mixtures thereof.

In another broad aspect of the present invention, packaging systems are provided which comprise a contact lens ready for use in an eye, a liquid medium, and a container holding the contact lens and the liquid medium. The contact lens comprises a contact lens body including a hydrophilic polymeric material and a WSPC, as described elsewhere herein. The liquid medium, preferably an aqueous liquid medium, comprises an amount of the WSPC in addition to that present in the contact lens body.

The liquid medium preferably includes the WSPC prior to the liquid medium being placed in the container, for example, in contact, with the contact lens.

Advantageously, the container is sealed, for example, using any suitable conventional container seal assembly, such as a conventional container seal assembly, and preferably sterilized to protect, preserve and maintain sterilized the contact lens and the liquid medium during shipment and storage.

In a further broad aspect of the present invention, methods for producing contact lenses are provided. Such methods comprise polymerizing at least one hydrophilic monomeric component in the presence of a WSPC to form a contact lens body comprising a hydrophilic polymeric material and the WSPC. Advantageously, an effective amount of at least one cross-linking monomeric component is present during the polymerizing step. The contact lens body is placed in a packaging container, preferably in a packaging system as described elsewhere herein.

Advantageously the polymerizing step is a solution polymerizing step. The WSPC preferably is included in a diluent used during the polymerizing step. The polymerizing step preferably occurs in a contact lens mold, for example, a conventional contact lens mold, such as a conventional thermoplastic contact lens mold.

In one very useful embodiment, a liquid medium, preferably an aqueous liquid medium, is also placed in the packaging container. This liquid medium preferably includes an amount of the WSPC in addition to that present in the contact lens body. The WSPC and the liquid medium preferably are ophthalmically acceptable.

In addition, the present methods preferably further comprise sealing the container with a contact lens body, and preferably the liquid medium, included therein.

Each and every feature described herein, and each and every combination of two or more of such features, is included within the scope of the present invention provided that the features included in such a combination are not mutually inconsistent.

These and other aspects of the present invention are set forth in the following detailed description, examples and claims, particularly when considered in conjunction with the accompanying drawings in which like parts bear like reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a packaging system in accordance with the present invention.

DETAILED DESCRIPTION

The present contact lenses comprise a contact lens body comprising a hydrophilic polymeric material and a WSPC, preferably an effective amount of the WSPC, for example, to increase the modulus or strength of the contact lens and/or to provide enhanced lubrication to the eye wearing the contact lens and/or to increase the comfort to the lens wearer of wearing the contact lens. Such benefits, e.g., increases and/or enhancements, are relative to an identical contact lens without the WSPC.

The hydrophilic polymeric materials useful in the present contact lenses may be selected from any suitable such materials. Preferably, such hydrophilic polymeric materials are such as to take on or absorb sufficient water so as to expand or swell. Such water-swellable materials are often referred to as hydrogels. A number of hydrophilic polymeric materials are conventionally used in contact lenses, and such conventionally used materials may be employed in the present contact lenses. Specific examples, without limitation, of useful hydrophilic polymeric materials are identified elsewhere herein.

An important feature of the present invention is the inclusion of WSPCs in the present contact lenses.

The WSPCs useful in the present invention may be chosen from any suitable such components. The presently useful WSPCs advantageously are ophthalmically acceptable and substantially not cytotoxic.

In a very useful embodiment, the WSPC is effective to provide at least one benefit to the contact lens and/or to the wearing of the contact lens and/or to the wearer of the contact lens. For example, the WSPC advantageously is present in an amount effective to increase the modulus or strength of the contact lens relative to an identical contact lens in which the WSPC is replaced by water. The WSPC may be selected, and present in the contact lens in an amount, so as to be effective as a lubricant or lubricity agent as the WSPC dissolves into the tear fluid while the contact lens is in use in an eye. Thus, the lens wearer’s eye, for example, cornea and/or eyelids, is more effectively lubricated when wearing the present contact lenses, which enhances the comfort of wearing the lenses, relative to an identical contact lens in which the WSPC is replaced by water.

The WSPC may be selected to have substantially no detrimental effect on the optical clarity and/or optical power of the contact lens while in use.

Specific examples, without limitation, of useful WSPCs are identified elsewhere herein. The XVSPC ma be included in the present contract lenses in any suitable amount effective to provide the desired result. Such amounts may be in a range of about 1% or about 5% or about 10% or about 15% to about 20% or about 30% or about 40% or about 50% or more of the hydrophilic polymeric material present in the contact lens.

One very useful class of WSPCs include polyethylene glycols. Polyethylene glycols are compounds that can be represented by the following formula: HO–(CH.sub.2–CH.sub.2O).sub.n–H wherein n represents a number such that the molecular weight of the polyethylene glycol is within the range of from about 300 to about 10,000 and preferably from about 400 to about 2000 or about 5000. Such polyethylene glycols are commercially available products.

The WSPCs employed are ultimately water-displaceable. That is, after placing the contact lens including the hydrophilic polymeric material and the WSPC in the eye, the WSPC is ultimately at least partially, and even substantially completely, replaced with water in the eye.

However, it is advantageous to provide the WSPCs in the present contact lenses so that the hydrophilic polymeric material physically immobilizes the WSPC, at least to a limited extent. For example, the hydrophilic polymeric material may immobilize the WSPC in the contact lens sufficiently so that the WSPC is replaced by water substantially only after the lens is placed in an eye. In one useful embodiment, the WSPC is present in the present contact lenses in an interpenetrating network or pseudo penetrating network with the hydrophilic polymeric material, for example, to provide the desired degree of physical immobilization of the WSPC.

The replacement, for example, controlled replacement, of the WSPC by water in the eye, can allow the WSPC, in the eye, to provide added lubrication and comfort to the lens wearer. In addition, the removal of the WSPC from the contact lens in the eye may reduce the modulus or strength of the lens. Thus, after the lens wearer removes the WSPC-depleted lens from his/her eye, the lens will have different strength properties than before it was placed in the eye. These different properties provide an indication to the wearer that the lens is to be disposed of, rather than to be reused. In other words, the replacement of the WSPC in the contact lens with water in the eye, advantageously facilitates lens wearer compliance with proper usage of disposable contact lenses. The present lenses preferably are structured to be disposed of after a single use in the eye.

Mixtures of two or more WSPCs may be included in a single contact lens in accordance with the present invention.

The hydrophilic polymeric material employed in the present contact lenses may be derived from any suitable monomer or mixture of monomers. In one embodiment, a monomer mixture used which contains a major proportion of at least one hydrophilic monomer such as 2-hydroxyethyl methacrylate (“HEMA”) as the major component, one or more cross-linking monomers, and optionally small amounts of other monomers such as methacrylic acid. HEMA is one preferred hydrophilic monomer. Other hydrophilic monomers that can be employed include, without limitation, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, N-vinyl pyrrolidone, glycerol mono-methacrylate, glycerol mono-acrylate, and the like and mixtures thereof.

The cross-linking monomers that can be employed, either singly or in combination, include, without limitation, ethylene glycol dimethacrylate (“EGDMA”), trimethylolpropane trimethacrylate (“TMPTMA”), glycerol trimethacrylate, polyethylene glycol dimethacrylate (wherein the polyethylene glycol has a molecular weight up to, for example, about 5000), other polyacrylate and polymethacrylate esters, end-capped polyoxyethylene polyols containing two or more terminal methacrylate moieties and the like and mixtures thereof. The cross-linking monomer is used in the usual amounts, e.g., from about 0.01% or less to about 0.5% or more, by weight of the reactive monomer mixture. The cross-linking monomer can be a hydrophilic monomer.

Other monomers that can be used include methacrylic acid, which is used to influence the amount of water that the hydrophilic polymeric material absorbs at equilibrium. Methacrylic acid is usually employed in amounts of from about 0.2 to about 8 parts, by weight, per 100 parts of hydrophilic monomer. Other monomers that can be present in the polymerization mixture include methoxyethyl methacrylate, acrylic acid, ultra-violet absorbing monomers, and the like and mixtures thereof.

A polymerization catalyst is included in the monomer mixture. The polymerization catalyst can be a compound such as lauroyl peroxide, benzoyl peroxide, isopropyl percarbonate, azobisiso-butyronitrile, and the like and mixtures thereof, that generates free radicals at moderately elevated temperatures, or the polymerization catalyst can be a photoinitiator system such as an aromatic a-hydroxy ketone or a tertiary amine plus a diketone. Illustrative examples of photoinitiator systems are 2-hydroxy-2-methyl-1-phenyl-propan-1-one and a combination of camphorquinone and ethyl 4-(N,N-dimethyl-amino)benzoate. The catalyst is used in the polymerization reaction mixture in catalytically effective amounts, e.g., from about 0.1 to about 2 parts by weight per 100 parts of hydrophilic monomer.

The presently useful WSPCs preferably are included in the contact lenses during polymerization, for example, solution polymerization, to produce the hydrophilic polymeric material. In a particularly useful embodiment, the WSPC in the contact lens is derived from a diluent material used during such polymerization of the hydrophilic polymeric material.

In another broad aspect, the present invention is directed to methods of producing contact lenses. Such methods comprise polymerizing, preferably solution polymerizing at least one hydrophilic monomeric component in the presence of a WSPC to form a contact lens body comprising a hydrophilic polymeric material and the WSPC. The WSPC preferably is included in a diluent used during the polymerizing step. The contact lens body is ready for use in the eye and is advantageously placed in a packaging container, for example, for shipment and/or storage.

The polymerizing step advantageously occurs in a contact lens mold, for example, a conventional contact lens mold. The polymerizing step may take place in a manner substantially similar or analogous to the corresponding step in the conventional wet cast molding process for making hydrophilic contact lenses. The polymerization reaction conditions useful in the present methods are substantially the same as those used in conventional wet cast molding processes for producing hydrophilic contact lenses and, therefore, are not detailed herein.

The resulting contact lens body preferably includes an interpenetrating network or a pseudo interpenetrating network of the hydrophilic polymeric material and the WSPC. One important feature of the present methods is that the WSPC is not replaced, for example, with water, prior to the contact lens being placed into a packaging container or into an eye. As described elsewhere herein, the WSPC in the contact lens in the eye produces one or more benefits.

In a further broad aspect, the present invention is directed to package systems for contact lenses, for example, the present contact lenses. Such package systems comprise a contact lens ready for use in an eye, a liquid medium, preferably an aqueous liquid medium, and a container holding the contact lens and the liquid medium. The contact lens comprises a contact lens body comprising a hydrophilic polymeric material and a WSPC, as described elsewhere herein.

The liquid medium comprises an amount of the WSPC in addition to the WSPC present in the contact lens body. Although the WSPC in the liquid medium need not be the same as the WSPC in the lens body, preferably it is substantially the same WSPC as that present in the lens body. Advantageously, the liquid medium includes the WSPC prior to the liquid medium being placed in contact with the lens body. The presence of the WSPC in the liquid medium preferably is effective to inhibit migration of the WSPC in the lens body from the lens body. Thus, the amount or concentration of the WSPC in the lens body is substantially maintained in the packaging system, and is available for providing one or more benefits, as described elsewhere herein, after the contact lens is placed in an eye. The concentration of the WSPC in the liquid medium may be about equal to, or somewhat more or less than, that present in the lens body prior to the lens body being placed in contact with the liquid medium. The liquid medium, other than the WSPC, may have a composition substantially similar or analogous to liquid medium used in package systems for conventional hydrophilic contact lenses. Saline solutions, buffered saline solutions, other aqueous solutions and the like, together with the WSPC, may be employed.

The container advantageously is sealed, after placing the contact lens and liquid medium in the container, to preserve these components during shipment and storage. The container and seal may be substantially similar or analogous to a conventional blister pack which is used for packaging conventional hydrophilic contact lenses.

Referring now to FIG. 1, a package system in accordance with the present invention is shown at 10. Package system 10 includes a container 12, a contact lens 14, including a contact lens body including a hydrophilic polymeric material and a WSPC, a liquid medium 16, comprising an aqueous saline solution containing a separate amount of the WSPC present in the contact lens, and a removable seal 18.

The container 12 and seal 18 are similar to the container and seal used in a conventional blister pack used with conventional hydrophilic contact lenses.

With the container 12 unsealed, the liquid medium 16 and the contact lens 14, directly from the contact lens mold, are placed therein. The seal 18 is placed over, and secured to the top of container 12, thereby sealing the compartment 20 containing the contact lens 14 in contact with the liquid medium 16.

The contact lens 14 can be used by opening seal 18 (as shown by the shadow lines in FIG. 1), removing lens 14 from compartment 20 and placing the lens into one’s eye. The container 12, liquid medium 16 and seal 18 can then be properly disposed of.

The following non-limiting examples illustrate certain aspects of the present invention:

EXAMPLE 1

A one day disposable, hydrogel-containing contact lens is wet cast molded in a polypropylene mold as follows. A monomer mixture of 98% by weight of 2-hydroxyethyl methacrylate, 1.6% by weight methacrylic acid and 0.4% by weight of ethylene glycol dimethacrylate is formed together with an effective amount of a conventional thermal initiator. This monomer is diluted by 20% by weight with water soluble polyethylene glycol having a molecular weight of about 1000. The diluted solution is added to a polypropylene contact lens mold and is cured using thermal curing. If desired, an ultraviolet light initiator can be included in place of the thermal initiator, and the solution can be cured using ultraviolet light curing. After curing, the lens is removed from the mold and placed in a packaging system similar to a conventional blister pack and hydrated with saline solution. The hydrated lens is formed to have mechanical properties similar to a dry cast molded lens.

EXAMPLE 1A

Alternately, and advantageously, the saline solution used in the package is altered to include about 20% of the polyethylene glycol, which is at substantial equilibrium with both the contact lens and the saline solution in the package. The use of this polyethylene glycol in the saline solution is effective to reduce, or even substantially eliminate, the polyethylene glycol from diffusing out of the contact lens during storage in the package.

EXAMPLE 2

A one day disposable, hydrogel-containing contact lens is wet cast molded in a polypropylene mold as follows. A monomer mixture of 98% by weight of 2-hydroxyethyl methacrylate, 1.6% by weight methacrylic acid and 0.4% by weight of ethylene glycol dimethacrylate is formed together with an effective amount of a conventional thermal initiator. This monomer is diluted by 30% by weight with water soluble polyethylene glycol having a molecular weight of about 1000. The diluted solution is added to a polypropylene contact lens mold and is cured using thermal curing. If desired, an ultraviolet light initiator can be included in place of the thermal initiator, and the solution can be cured using ultraviolet light curing. After curing, the lens is removed from the mold and placed in a packaging system similar to a conventional blister pack and hydrated with saline solution. The hydrated lens is formed to have mechanical properties similar to a dry cast molded lens.

EXAMPLE 2A

Alternately, and advantageously, the saline solution used in the package is altered to include about 30% of the polyethylene glycol, which is at substantial equilibrium with both the contact lens and the saline solution in the package. The use of this polyethylene glycol in the saline solution is effective to reduce, or even substantially eliminate, the polyethylene glycol from diffusing out of the contact lens during storage in the package.

EXAMPLE 3

A one day disposable hydrogel-containing contact lens is wet cast molded in a polypropylene mold as follows. A monomer mixture of 98% by weight of 2-hydroxyethyl methacrylate, 1.6% by weight methacrylic acid and 0.4% by weight of ethylene glycol dimethacrylate is formed together with an effective amount of a conventional thermal initiator. This monomer is diluted by 40% by weight with water soluble polyethylene glycol having a molecular weight of about 1000. The diluted solution is added to a polypropylene contact lens mold and is cured using thermal curing. If desired, an ultraviolet light initiator can be included in place of the thermal initiator, and the solution can be cured using ultraviolet light curing. After curing, the lens is removed from the mold and placed in a packaging system similar to a conventional blister pack and hydrated with saline solution. The hydrated lens is formed to have mechanical properties similar to a dry cast molded lens.

EXAMPLE 3A

Alternately, and advantageously, the saline solution used in the package is altered to include about 40% of the polyethylene glycol, which is at substantial equilibrium with both the contact lens and the saline solution in the package. The use of this polyethylene glycol in the saline solution is effective to reduce, or even substantially eliminate, the polyethylene glycol from diffusing out of the contact lens during storage in the package.

EXAMPLE 4

A one day disposable hydrogel-containing contact lens is wet cast molded in a polypropylene mold as follows. A monomer mixture of 98% by weight of 2-hydroxyethyl methacrylate, 1.6% by weight methacrylic acid and 0.4% by weight of ethylene glycol dimethacrylate is formed together with an effective amount of a conventional thermal initiator. This monomer is diluted by 50% by weight with water soluble polyethylene glycol having a molecular weight of about 1000. The diluted solution is added to a polypropylene contact lens mold and is cured using thermal curing. If desired, an ultraviolet light initiator can be included in place of the thermal initiator, and the solution can be cured using ultraviolet light curing. After curing, the lens is removed from the mold and placed in a packaging system similar to a conventional blister pack and hydrated with saline solution. The hydrated lens is formed to have mechanical properties similar to a dry cast molded lens.

EXAMPLE 4A

Alternately, and advantageously, the saline solution used in the package is altered to include about 50% of the polyethylene glycol, which is at substantial equilibrium with both the contact lens and the saline solution in the package. The use of this polyethylene glycol in the saline solution is effective to reduce, or even substantially eliminate, the polyethylene glycol from diffusing out of the contact lens during storage in the package.

EXAMPLE 5

A one day disposable hydrogel-containing contact lens is wet cast molded in a polypropylene mold as follows. A mixture of 48.8% by weight of 2-hydroxyethyl methacrylate, 0.5% by weight methacrylic acid, 0.7% by weight of a cross-linking component sold under the tradename Craynor 435 and 50% by weight of methyl terminated polyethylene glycol having a molecular weight of about 350 (PEGME-350) is formed together with an effective amount of a conventional thermal initiator. This mixture is added to a polypropylene contact lens mold and is cured using thermal curing. If desired, an ultraviolet light initiator can be included in place of the thermal initiator, and the mixture can be cured using ultraviolet light curing. After curing, the lens is removed from the mold and placed in a packaging system similar to a conventional blister pack and hydrated with saline solution. The hydrated lens is formed to have mechanical properties similar to a dry cast molded lens.

EXAMPLE 5A

Alternately, and advantageously, the saline solution used in the package is altered to include about 50% of the PEGME-350, which is at substantial equilibrium with both the contact lens and the saline solution in the package. The use of this methyl terminated polyethylene glycol in the saline solution is effective to reduce, or even substantially eliminate, the methyl terminated polyethylene glycol from diffusing out of the contact lens during storage in the package.

EXAMPLE 6

A one day disposable hydrogel-containing contact lens is wet cast molded in a polypropylene mold as follows. A mixture of 37.3% by weight of 2-hydroxyethyl methacrylate, 0.6% by weight methacrylic acid, 0.2% by weight of ethylene glycol dimethacrylate, 30.8% by weight of polyethylene glycol having a molecular weight of about 300 and 31.1 by weight of deionized water is formed together with an effective amount of a conventional thermal initiator. The mixture is added to a polypropylene contact lens mold and is cured using thermal curing. If desired, an ultraviolet light initiator can be included in place of the thermal initiator, and the mixture can be cured using ultraviolet light curing. After curing, the lens is removed from the mold and placed in a packaging system similar to a conventional blister pack and hydrated with saline solution. The hydrated lens is formed to have mechanical properties similar to a dry cast molded lens.

EXAMPLE 6A

Alternately, and advantageously, the saline solution used in the package is altered to include about 30.8% of the polyethylene glycol, which is at substantial equilibrium with both the contact lens and the saline solution in the package. The use of this polyethylene glycol in the saline solution is effective to reduce, or even substantially eliminate, the polyethylene glycol from diffusing out of the contact lens during storage in the package.

EXAMPLE 7 TO 18

Each of twelve (12) patients removes a different one of the lenses produced in accordance with Examples 1 to 6 and 1A to 6A from the solution and places it on his/her eye. In each case, while the lens is on the patient’s eye, the polyethylene glycol or methyl terminated polyethylene glycol diffuses out of the lens and into the eye, thereby advantageously increasing the lubrication of the cornea and the eyelid of the eye.

If the patient was to remove the lens, place it into a saline solution and wear it again the next day, the lens would be significantly less comfortable to wear due to the loss of the polyethylene glycol, or methyl terminated polyethylene glycol and the loss of lubrication. In addition, because of the loss of the polyethylene glycol, or methyl terminated polyethylene glycol, the lens has less modulus or strength and appears more “floppy” after the lens is worn in the eye. In effect, the loss of the polyethylene glycol, or methyl terminated polyethylene glycol from the contact lens creates a trigger mechanism and/or provides an indication to the patient to be compliant with the one day disposable modality.

While this invention has been described with respect to various specific examples and embodiments, it is to be understood that the invention is not limited thereto and that it can be variously practiced within the scope of the following claims.

1. A method for producing a pattern for tinted contact lenses, comprising the steps of: a.) defining an inner and an outer pattern boundary; b.) selecting a starting angle, a travel distance, and a change angle; c.) selecting a starting string, an iteration string, and a number of iterations to be executed; d.) generating the pattern using at least one algorithm, wherein the algorithm is fractal in nature; and e.) producing a contact lens comprising the pattern.

2. The method of claim 1, wherein the at least one algorithm is derived from one of chaotic systems, diffusion systems, aggregation systems, L-systems, P-systems, cellular automata.

3. The method of claim 2, wherein the algorithm is derived from an L-system.

4. The method of claim 3, wherein the algorithm is derived from a modified L-system that is a 5.sup.th order L-system constrained to produce a pattern P within a region defined by: R.sub.outer.+-.delta.sub.outer

5. The method of claim 2, wherein the algorithm is derived from a diffusion system.

6. The method of claim 5, further comprising the steps of: a.) defining a boundary for a horizon and a substrate; b.) selecting a maximum and a minimum circle radius; and c.) generating a pattern using the algorithm.

7. A tinted contact lens produced using the method of claim 1.

8. A tinted contact lens produced using the method of claim 2.

9. A tinted contact lens produced using the method of claim 3.

10. A tinted contact lens produced using the method of claim 4.

11. A tinted contact lens produced using the method of claim 5.

12. A tinted contact lens produced using the method of claim 6.
Contact Lens Description
FIELD OF THE INVENTION

The invention relates to tinted contact lenses. In particular, the invention provides methods for designing contact lenses that either enhance or change the color of one or more of a lens wearer’s iris, limbal ring, and pupil.

BACKGROUND OF THE INVENTION

The use of tinted, or colored, contact lenses to either or both alter the natural color of the eye and to mask ophthalmic abnormalities is well known. Typically, these lenses incorporate a pattern in the portion of the lens that overlies one or more of the iris, pupil, and limbal ring of the lens wearer when the lens is on-eye.

The conventional method for providing the pattern is drawing the pattern by hand or by using a computer graphics program. Alternatively, the pattern may be formed by taking a digital image of one or more of an actual iris, pupil or limbal ring and extracting portions of the images for use in a pattern. These methods are disadvantageous in that accurately describing the resulting patterns for purposes of creating tooling for production of lenses incorporating the pattern, application of the pattern to a lens mold, pattern metrology and the like are challenging due to the complex geometries of the patterns.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow diagram of a method of the invention.

FIG. 2 is a flow diagram of a second method of the invention.

FIG. 3 is pattern produced according to a method of the invention.

FIG. 4 is a second pattern produced according to a method of the invention.

FIG. 5 is a third pattern produced according to a method of the invention.

FIG. 6 is a flow diagram of a third method of the invention.

FIG. 7 is a flow diagram of a fourth method of the invention.

FIG. 8 is a fourth pattern produced according to a method of the invention.

FIG. 9 is a fifth pattern produced according to a method of the invention.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS

The invention provides methods for designing patterns for use in tinted contact lenses, methods for the manufacture of such lenses, and lenses incorporating the patterns in which the patterns are generated using algorithms. The resulting patterns, when incorporated into a contact lens, serve to enhance or alter the color of one or more of the wearer’ iris, pupil, and limbal ring. The method of the invention provides an objective description of the pattern for purposes of tooling, metrology and manufacturing of a lens incorporating the pattern.

In one embodiment, the invention provides a method for producing patterns for tinted contact lenses comprising, consisting essentially of, and consisting of the step of generating at least a portion of a pattern using at least one algorithm. For purposes of the invention by “algorithm” is meant a set of rules that produce a set of points and includes, without limitation, one or more mathematical formulae.

In the method of the invention, one or more algorithms are used to generate at least a portion of a pattern useful in a tinted contact lens. Algorithms for use in the invention are fractal in nature. Suitable algorithms may be derived from structures such as, without limitation, chaotic systems, diffusion systems, aggregation systems, L-systems, P-system, cellular automata and the like.

As one example, the algorithm is derived from an L-system. Shown in FIG. 1 is a flow diagram for deriving such an algorithm and producing a pattern according to the invention. In a first step (101), the inner and outer pattern boundaries are defined. The boundaries may be of any suitable size and shape. Typically, the boundaries will be that of the average radius of one or more of the human pupil, iris, and limbal ring. The outer and inner boundaries may be changed by adding or subtracting a small fraction, delta.sub.inner or delta.sub.outer, of the corresponding starting radius to the boundary (102). This change may be made stochastic by multiplying delta.sub.inner or delta.sub.outer by a random number between 0 and 1, the resulting effect of which will be to make the boundary appear more natural. The change may be made, and random variable selected, at each iteration step, meaning at each time a line segment is drawn. Additionally, a starting angle, travel distance, and change angle are randomly selected (103) along with the starting string, iteration string, and number of iterations to be executed (104). The algorithm is then run to generate a pattern (105) and a determination is made as to whether the resulting pattern is acceptable (106). If the pattern is not acceptable, the process is repeated changing some or all of the parameters and constraints.

In a more specific example, an algorithm is derived from an L-system and the boundary conditions limit the graphical commands of the L-system’s symbols to an area that is substantially equal to the area covered by a conventional cosmetic lens iris pattern. Additionally and preferably, a stochastic element is provided to this L-system. More particularly, a 5.sup.th order L-system is constrained to produce a pattern within a region defined by two circles. In other words, the pattern (“P”) is produced within a region defined by: R.sub.outer.+-.delta.sub.outer

The algorithm for this system begins with a starting string, or axiom, composed of symbols representing graphical commands. The commands are used by computer code to draw line segments, defined in units of pixels, that compose a pattern for use in a tinted lens. For example, the axiom may be the symbols “F-F” and, during the first iteration, an iteration string randomly chosen by the designer is substituted for each “F.” The code then executes the command in the new string. In a second iteration, the iteration string is substituted for each “F” in the previous string and the code executes these commands.

For example, if the iteration string for the axiom “F-F” is “F+F+”, after the first iteration the string is “F+F+-F+F+.” After the second iteration, the string is “F+F++F+F+F++-F+F++F+F++.” Subsequent iterations are carried out until a predefined number of iterations, determined by the order of the system, has occurred. For example, 5 iterations would be carried out for a 5.sup.th order L-system. The order used will be determined by observation of which order provides the desired pattern.

Graphical meanings are associated with the symbols for the axiom. For example, the symbols for the axiom above are set forth in the table below.

TABLE-US-00001 Symbol Meaning F Draw line of prescribed travel distance from the previous position to the final position wherein the final position is defined by the direction angle and the travel distance. + Change current angle – turn left by turning angle. & Change current angle – turn right by turning angle. – Change angle by reflecting across horizontal (x) axis.

In the table above, the travel distance is the selected length. The values for the travel distance, or length, of the line segment drawn when the F symbol is encountered, the turning angle, or the change in angle occurring when a “+” or “&” symbol is encountered, the iteration string, and the new starting position of the line segments when a boundary condition violation has occurred are all selected by the designer. Each of these values will be determined by the values that produce a desirable pattern, meaning a pattern that when incorporated into a lens achieves a desirable on-eye cosmetic effect.

The starting position of the first line segment is chosen randomly at a position near the inner circle. If the line segments are to be drawn within R.sub.outer.+-.delta.sub.outer and within R.sub.inner.+-.delta.sub.inner and a line segment is greater than R.sub.outer.+-.delta.sub.outer or less than R.sub.inner.+-.delta.sub.inner, a new starting position for the segments that is within these constraints will be randomly chosen at a distance times a random number between 0 and 1 from R.sub.inner after which the code will continue with the execution of the graphical commands. If a line segment is within R.sub.outer.+-.delta.sub.outer and R.sub.inner.+-.delta.sub.inner no change will be made. In FIG. 2 is a flow diagram of such a method.

FIGS. 3 through 5 are examples of patterns generated by the methods shown in FIGS. 1 and 2. For purposes of these figures, the outer and inner circles are 350 and 150 pixels, respectively. As shown in FIGS. 3 through 5, the inner and outer circle boundaries are fuzzy meaning that, when the final position of each line segment is defined, the algorithm checks to determine whether a boundary that changes randomly about the inner and outer circle boundaries was exceeded. Additionally, there is a stochastic nature to the algorithm used in that, if the boundary condition has been exceeded, a new starting position for the line segment will be selected randomly.

In FIG. 3 is depicted a pattern 10 suitable for use as a pattern in a cosmetic contact lens. The pattern 10 was generated after five iterations using the axiom F-F and the iteration string of F&F&F&F&F+F+F+F+. The starting angle was 180 degrees from the horizontal, the travel distance was 5 pixels, and the turning angle was 45 degrees and the rimover distance was 150 pixels. FIG. 4 depicts pattern 20 generated after 5 iterations and using the same axiom, iteration string, starting angle and travel distance as for FIG. 3, but using a turning angle of 22.5 degrees and a rimover distance of 200 pixels. The pattern 30 of FIG. 5 was generated as was the pattern for FIG. 3 except that a travel distance of 2 pixels was used.

The designs shown in FIGS. 3 through 5 are the result of the use of an algorithm used to draw line segments. As another example, an algorithm may be used to generate patterns similar to a physical process, such as diffusion. For example, a pattern may be developed by launching a defined number of circles and allowing each circle to find its location.

FIG. 6 shows a flow diagram of such a process. In a first step (201), horizon and substrate pattern boundaries, preferably which are circles, are defined. By horizon is meant the position from which the circles are launched. By substrate is meant the position at which the launched circles accumulate. The horizon and substrate circles may be of any radii, but preferably the horizon circle is concentric with and has a larger radius than the substrate circle. The horizon and substrate boundaries may be altered (202) at each iteration step by adding or subtracting a randomly chosen fraction of the corresponding starting horizon or substrate radius. The extent of this randomly chosen fraction will be determined by visually inspecting the impact this alteration has on the resultant pattern.

In this embodiment of the method of the invention, the criteria for selecting the minimum and maximum number of circles to be launched (203) is based on the extent to which the area between the circles is to be filled so as to produce a desirable pattern. This will be determined by visually inspecting the impact made on the resultant pattern when changing the minimum and maximum number of circles. The same criteria is used to select the maximum and minimum radius of the launched circles (204). The algorithm is then run to generate a pattern (205) and a determination is made as to whether the pattern is acceptable (206).

More specifically by way of example and as shown in the flow diagram of FIG. 7, the algorithm may be such that small circles are launched from a circular horizon using random locations and trajectories (301). Each circle is permitted to move until it either encounters another circle (302) or exceeds the R.sub.horizon.+-.delta.sub.horizon boundary (303). If a launched circle comes in contact with another such circle, it is placed at the point of contact and another circle is then launched from that point. If a launched circle moves beyond the R.sub.horizon.+-.delta.sub.horizon boundary, it is removed (304) and another circle is launched or if a launched circle is within the R.sub.horizon.+-.delta.sub.horizon boundary, no change is made (305). Alternatively, the horizon circle’s radius may be randomly changed by a small amount when a query is made as to whether a particle has moved beyond the horizon circle radius.

As a launched circle traverses the region between other circles and the substrate circle, it may collide with a background particle. A background particle is a particle, preferably invisible, that changes the trajectory of one of the circles used to define the pattern. Such a collision is elastic in that the circle’s trajectory may be changed by some random factor due to the collision. The probability of having such a collision may be controlled by use of a variable that acts similarly to a temperature and density variable and, thus, may be considered as a diffusion coefficient.

Along with the collision probability, the designer may vary the horizon and substrate radii and the number of launched circles and their radii. In FIGS. 8 and 9 are shown examples using such an algorithm. For purposes of these examples, the diffusion coefficient was infinite, meaning that there were no background collisions.

In the FIG. 8 is shown pattern 40 generated using the above-described diffusion algorithm, a horizon radius of 750 pixels, a substrate radius of 450 pixels and 100,000 circles each having a radius of 1 pixel. Pattern 50 shown in FIG. 9 was generated using the diffusion algorithm, a horizon radius of 750 pixels, a substrate radius of 550 pixels, and 100,000 launched circles each with a radius of 1 pixel.

Using the method of the invention, patterns for tinted contact lenses may be created, which patterns are defined by one or more algorithms. The patterns may be used in a lens for either enhancing or altering one or more of the wearer’s iris, pupil, and limbal ring color and the elements of the pattern may be translucent or opaque depending on the desired on-eye result. For purposes of the invention, by “translucent” is meant a color that permits an average light transmittance (% T) in the 380 to 780 nm range of about 60 to about 99%, preferably about 65 to about 85% T. By “opaque” is meant a color that permits an average light transmittance (% T) in the 380 to 780 nm range of 0 to about 55, preferably 7 to about 50% T.

The color of the pattern elements may be substantially the same as, or complementary to, each other and the color selected for the pattern elements will be determined by the natural color of the lens wearer’s iris and the enhancement or color change desired. Thus, elements may be any color including, without limitation, any of a variety of hues and chromas of blue, green, gray, brown, black yellow, red, or combinations thereof. Preferred colors for a limbal ring include, without limitation, any of the various hues and chromas of black, brown and gray.

The pattern elements, may be made from any organic or inorganic pigment suitable for use in contact lenses, or combinations of such pigments. The opacity may be controlled by varying the concentration of one or both of the pigment and titanium dioxide used, with higher amounts yielding greater opacity. Illustrative organic pigments include, without limitation, pthalocyanine blue, pthalocyanine green, carbazole violet, vat orange #1, and the like and combinations thereof. Examples of useful inorganic pigments include, without limitation, iron oxide black, iron oxide brown, iron oxide yellow, iron oxide red, titanium dioxide, and the like, and combinations thereof. In addition to these pigments, soluble and non-soluble dyes may be used including, without limitation, dichlorotriazine and vinyl sulfone-based dyes. Useful dyes and pigments are commercially available.

The dye or pigment selected may be combined with one or more of a pre-polymer, or binding polymer, and a solvent to form the colorant used to produce the translucent and opaque layers used in the lenses of the invention. Other additives useful in contact lens colorants also may be used. The binding polymers, solvents, and other additives useful in the color layers of the invention are known and either commercially available or methods for their making are known.

The elements may be applied to, or printed on, one or more surfaces of a lens or may be printed onto one or more surfaces of a mold into which a lens forming material will be deposited and cured. In a preferred method for forming lenses incorporating the designs of the invention, a thermoplastic optical mold, made from any suitable material including, without limitation, cyclic polyolefins and polyolefins such as polypropylene or polystyrene resin is used. The elements are deposited onto the desired portion of the molding surface of the mold. By “molding surface” is meant the surface of a mold or mold half used to form a surface of a lens. Preferably, the deposition is carried out by pad printing as follows.

A metal plate, preferably made from steel and more preferably from stainless steel, is covered with a photo resist material that is capable of becoming water insoluble once cured. The elements are selected or designed and then reduced to the desired size using any of a number of techniques such as photographic techniques, placed over the metal plate, and the photo resist material is cured.

The plate is subsequently washed with an aqueous solution and the resulting image is etched into the plate to a suitable depth, for example about 20 microns. A colorant containing a binding polymer, solvent, and pigment or dye is then deposited onto the elements to fill the depressions with colorant. A silicon pad of a geometry suitable for use in printing on the surface and varying hardness, generally about 1 to about 10, is pressed against the image on the plate to remove the colorant and the colorant is then dried slightly by evaporation of the solvent. The pad is then pressed against the molding surface of an optical mold. If necessary, the mold is degassed for up to 12 hours to remove excess solvents and oxygen after which the mold is filled with lens material. A complementary mold half is then used to complete the mold assembly and the mold assembly is exposed to conditions suitable to cure the lens material used. Such conditions are well known in the art and will depend upon the lens material selected. Once curing is completed and the lens is released from the mold, it is equilibrated in a buffered saline solution.

In a preferred embodiment, a clear, pre-polymer layer is used, which pre-polymer layer overlays the pattern and may form the entirety of the lens’ outermost surface. The clear, pre-polymer layer preferably is first applied to the mold surface and the colorant is subsequently applied to the pre-polymer. The pre-polymer may be any polymer that is capable of dispersing the pigment and any opacifying agent used.

The invention may be used to provide tinted hard or soft contact lenses made of any known lens-forming material, or material suitable for manufacturing such lenses. Preferably, the lenses of the invention are soft contact lenses, the material selected for forming the lenses being any material suitable for producing soft contact lenses. Suitable preferred materials for forming soft contact lenses using the method of the invention include, without limitation, silicone elastomers, silicone-containing macromers including, without limitation, those disclosed in U.S. Pat. Nos. 5,371,147, 5,314,960, and 5,057,578 incorporated in their entireties herein by reference, hydrogels, silicone-containing hydrogels, and the like and combinations thereof. More preferably, the lens is made from a material containing a siloxane functionality, including, without limitation, polydimethyl siloxane macromers, methacryloxypropyl polyalkyl siloxanes, and mixtures thereof, a silicone hydrogel or a hydrogel made of monomers containing hydroxy groups, carboxyl groups, or both and combinations thereof. Materials for making soft contact lenses are well known and commercially available. Preferably, the lens material is acquafilcon, etafilcon, genfilcon, lenefilcon, balafilcon, lotrafilcon, or galyfilcon.

1. A soft hydrogel contact lens having a tensile modulus less than about 140 psi, oxygen transmissibility of at least about 70 barrers/mm and a dynamic coefficient of friction of less than about 0.01 when measured at a sliding speed of 10 cm/second, wherein said contact lens comprises at least one lubricious polymer in or on said contact lens, provided however, when said lubricious polymer is coated on said contact lens, said lubricious polymer is not polyacrylic acid or poly(N,N-dimethylacrylamide).

2. The contact lens of claim 1 wherein said oxygen transmissibility is at least about 85 barrers/mm.

3. The contact lens of claim 1 further comprising an advancing dynamic contact angle of less than about 90.degree..

4. The lens of claims 1 further comprising a water content of at least about 30%.

5. The lens of claim 1 wherein said oxygen transmissibility is at least about 80 barrers/mm.

6. The lens of claim 2 wherein said oxygen transmissibility is at least about 90 barrers/mm.

7. The lens of claim 1 wherein said oxygen transmissibility is at least about 110 barrers/mm.

8. The lens of claim 1 wherein said oxygen transmissibility is at least about 140 barrers/mm.

9. The lens of claim 3 wherein said advancing dynamic contact angle is less than about 80.degree..

10. The lens of claim 3 wherein said advancing dynamic contact angle is less than about 70.degree..

11. The lens of claim 4 wherein said water content is between about 30% and about 50%.

12. The lens of claim 6 wherein said lens further comprises a water content between about 30% and about 50%.

13. The lens of claim 1 further comprising a tensile modulus of less than about 120 psi.

14. The lens of claim 1 further comprising a tensile modulus of less than about 100 psi.

15. The lens of claim 1 further comprising a tensile modulus of about 40 to about 100 psi.

16. The lens of claim 2 wherein said lens is formed from a silicone hydrogel.

17. The lens of claim 16 wherein said silicone hydrogel is formed from a reaction mixture comprising at least about 20 weight % silicone containing components.

18. The lens of claim 16 wherein said silicone hydrogel is formed from a reaction mixture comprising between about 20 and about 70 weight % silicone containing components.

19. The lens of claim 17 wherein said reaction mixture comprises at least one monofunctional silicone containing component and less than about 10 mmol multifunctional components/100 g reactive components.

20. The lens of claim 19 wherein said multifunctional components comprise less than about 7 mmol/100 g of the reactive components.

21. The lens of claim 19 wherein said monofunctional silicone containing component is selected from the group consisting of polysiloxanylalkyl(meth)acrylic monomers, mono-functional polydimethylsiloxanes and mixtures thereof.

22. The lens of claim 19 wherein said multifunctional components comprise multifunctional silicone containing components.

23. The lens of claim 22 wherein said multifunctional silicone containing components are selected from the group consisting of poly(organosiloxane) prepolymer, multifunctional silicone-containing vinyl carbonate and vinyl carbamate monomers, polyurethane macromers, and combinations thereof.

24. The lens of claim 17 wherein at least about 30 weight % of said silicone components comprise silicone containing compounds free from branching trimethylsiloxy groups.

25. The lens of claim 17 wherein at least about 60 weight % of said silicone components comprise silicone containing compounds free from branching trimethylsiloxy groups.
Contact Lens Description
FIELD OF THE INVENTION

This invention relates to soft contact lenses displaying superior comfort when worn on eye. In particular, the invention relates to soft contact lenses displaying a unique combination of properties which provide superior on eye comfort.

BACKGROUND OF THE INVENTION

Soft contact lenses have been available since the 1980s. Currently there are two types of soft contact lenses. “Conventional” lenses are made from hydrophilic polymers such as poly(2-hydroxyethyl methacrylate) (PHEMA) and copolymers of N-vinyl pyrrolidone and methyl methacrylate. These contact lenses have relatively low permeability to oxygen (typically below 8-30 barrers), but high water content (typically in excess of 35%). Examples of a conventional soft contact lens include Acuvue.RTM. and Acuvue2.RTM. brand contact lenses, both of which are considered as among the most comfortable soft contact lenses commercially available. However, many lens wearers cannot comfortably wear conventional lenses for a full day (up to nine hours or more).

Contact lens wearers commonly report symptoms of dryness and discomfort while wearing contact lenses. These symptoms can be exacerbated in environments prone to low relative humidity, such as pressurized airline cabins, home or office environments that use forced-air heating or air-conditioning systems, as well as locales and environments subject to low ambient humidity. The relative humidity in commercial airlines commonly ranges from as low as 5% to under 40%, with mean values averaging between 14-19%.

Silicone hydrogel contact lenses contain silicone in the lens polymer. Silicone increases the lens’s oxygen permeability, which contributes to the lenses ability to be worn for longer periods of continuous wear. However, commercially available silicone hydrogel contact lenses are perceived by many lens wearers to be less comfortable than conventional contact lenses. Accordingly, there remains a need in the industry for a contact lens which can be worn comfortably for a full day of wear, even in low humidity environments.

SUMMARY OF THE INVENTION

The present invention relates to soft contact lenses having an overall comfort preference of at least about 2 to 1 as compared to an Acuvue.RTM. contact lens and measured after one week of daily wear.

The invention also relates to soft contact lenses having an overall comfort preference of at least about 2 to 1 as compared to an Acuvue2.RTM. contact lens and measured after one week of daily wear.

The invention further relates to soft contact lenses having a modulus of less than about 100 psi, oxygen transmissibility of at least about 80 barrers/mm and a dynamic coefficient of friction of less than about 0.01 when measured at a sliding speed of 10 cm/second, provided however, said contact lens is not coated with polyacrylic acid or poly(N,N-dimethylacrylamide).

DESCRIPTION OF THE FIGURES

FIG. 1 contains two photographs of the right eye of a clinical trial patient wearing spectacle lenses for one month.

FIG. 2 contains two photographs of the right eye of a clinical trial patient wearing the contact lenses of Example 5 for one month of daily wear.

FIG. 3 contains two photographs of the right eye of a clinical trial patient wearing Focus Night and Day.RTM. brand contact lenses for one month of daily wear.

FIG. 4 contains two photographs of the right eye of a clinical trial patient wearing Acuvue.RTM.2 brand contact lenses for one month of daily wear.

FIG. 5 is a graph comparing the limbal redness observed in patients wearing spectacle lenses, the contact lenses of Example 5, Focus Night and Day.RTM. brand contact lenses and Acuvue.RTM.2 brand contact lenses.

FIG. 6 is a graph comparing lid irritation observed in patients wearing spectacle lenses, the contact lenses of Example 5, Focus Night and Day.RTM. brand contact lenses and Acuvue.RTM.2 brand contact lenses.

FIG. 7 is a graph comparing the overall redness observed in patients wearing spectacle lenses, the contact lenses of Example 5, Focus Night and Day.RTM. brand contact lenses and Acuvue.RTM.2 brand contact lenses.

DETAILED DESCRIPTION OF THE INVENTION

It has been surprisingly found that contact lenses having a unique balance of properties display superior comfort compared to presently available soft contact lenses. The contact lenses of the present invention display superior overall comfort throughout wear, and at the end of the day. The lenses of the present invention were found, in clinical trials to be significantly more comfortable than Acuvue.RTM. or Acuvue.RTM.2 brand contact lenses, both of which are recognized in the industry as lenses which are among the most comfortable commercially available lenses. By significant, we mean a preference rating of at least 2 to 1 in a double masked, clinical trial with at least about 20 patients completing the trial and wearing lenses for at least 8 hours per day for at least one week. End of day comfort data was collected at least 8 hours after lens insertion. The questionnaires allowed participants the following choices: preferred the test lens, preferred the control lens, preferred both lenses or preferred neither lens. Ratings were generated using all responses indicating a preference between the lenses. Acuvue2.RTM. and Acuvue.RTM. brand contact lenses are soft hydrogel contact lenses made from etafilcon A and commercially available from Johnson & Johnson Vision Care, Inc.

Lenses of the present invention were also found to provide improved comfort in low humidity environments, generally under 40% relative humidity, such as airline cabins, heated and air conditioned buildings and the like.

It has been surprisingly found that lenses that have a modulus of less than about 140 psi, an oxygen transmissibility, Dk/t, of at least about 70 barrers/mm and a dynamic coefficient of friction (“COF”) of less than about 0.01, display superior comfort. Low modulus provides a soft and flexible lens. High oxygen transmissibility provides sufficient levels of oxygen to the cornea to prevent redness and promote corneal health, and a low dynamic COF provides the lens with a lubricious, silky feel.

Preferably the Dk/t is at least about 80 barrers/mm, in some embodiments at least about 90, and for contact lenses which are intended to be worn continuously for two weeks or more, preferably at least about 100 barrers/mm. In some embodiments, Dk/t of at least about 140 barrer/mm may be desirable.

Preferably the modulus is less than about 120 psi, more preferably less than about 100 psi, and in some embodiments between about 40 and 100 psi.

Additionally contact lenses of the present invention may have water contents of at least about 30%, and preferably between about. 30 and about 50%. The contact lenses of the present invention may also display advancing contact angles of less than about 80.degree. and preferably less than about 70.degree. as measured using a Wilhelmy dynamic contact angle balance.

Suitable components for producing soft contact lenses having a variety of properties are known in the art. The combination of components to provide the novel combination of properties disclosed in the present invention will now be described.

The oxygen transmissibility may be imparted to the lens formulation by including at least one silicone containing component in the lens formulation. Suitable silicone containing components include silicone containing monomers, prepolymer and/or macromers.

The term “monomer” used herein refers to lower molecular weight compounds that can be polymerized to higher molecular weight compounds, polymers, macromers, or prepolymers. The term “macromer” as used herein refers to a high molecular weight polymerizable compound. Prepolymers are partially polymerized monomers or monomers which are capable of further polymerization.

A “silicone-containing monomer” is one that contains at least two [--Si--O--] repeating units in a monomer, macromer or prepolymer. Preferably, the total Si and attached O are present in the silicone-containing monomer in an amount greater than 20 weight percent, and more preferably greater than 30 weight percent of the total molecular weight of the silicone-containing monomer. Useful silicone-containing components preferably comprise polymerizable functional groups such as acrylate, methacrylate, acrylamide, methacrylamide, N-vinyl lactam, N-vinylamide, and styryl functional groups. Examples of silicone-containing components which are useful in this invention may be found in U.S. Pat. Nos. 3,808,178; 4,120,570; 4,136,250; 4,153,641; 4,740,533; 5,034,461 and 5,070,215, and EP080539. All of the patents cited herein are hereby incorporated in their entireties by reference. These references disclose many examples of olefinic silicone-containing components.

While almost any silicone containing component may be included to increase the Dk of the resulting lens, in order to provide the lenses of the present invention with the desired modulus, the majority of the mass fraction of the silicone components used in the lens formulation should contain only one polymerizable functional group (“monofunctional silicone containing component”). To insure the desired balance of oxygen transmissibility and modulus it is preferred that all components having more than one polymerizable functional groups (“multifunctional components”) make up no more than 10 mmol/100 g of the reactive components, and preferably no more than 7 mmol/100 g of the reactive components. Suitable monofunctional silicone containing components include polysiloxanylalkyl(meth)acrylic monomers of Formula I:

##STR00001## wherein: R denotes H or lower alkyl; X denotes O or NR.sup.4; each R.sup.4 independently denotes hydrogen or methyl, each R.sup.1-R.sup.3 independently denotes a lower alkyl radical or a phenyl radical, and n is 1 or 3 to 10. Mono-functional polydimethylsiloxanes (mPDMS) may also be used. Suitable mPDMS compounds include Structure II:

##STR00002## where b=0 to 100, where it is understood that b is a distribution having a mode equal to a stated value, preferably 4 to 16, more preferably 8 to 10; R.sub.58 is a monovalent group containing at least one ethylenically unsaturated moiety, preferably a monovalent group containing a styryl, vinyl, or methacrylate moiety, more preferably a methacrylate moiety; each R.sub.59 is independently a monovalent alkyl, or aryl group, which may be further substituted with alcohol, amine, ketone, carboxylic acid or ether groups, preferably unsubstituted monovalent alkyl or aryl groups, more preferably methyl; R.sub.60 is a monovalent alkyl, or aryl group, which may be further substituted with alcohol, amine, ketone, carboxylic acid or ether groups, preferably unsubstituted monovalent alkyl or aryl groups, preferably a C.sub.1-10 aliphatic or aromatic group which may include hetero atoms, more preferably C.sub.3-8alkyl groups, most preferably butyl; and R.sub.61 is independently alkyl or aromatic, preferably ethyl, methyl, benzyl, phenyl, or a monovalent sloganeer chain comprising from 1 to 100 repeating Si–O units. Examples of suitable mPDMS compounds include 3-methacryloxy-2-hydroxypropyloxy)propylbis(trimethylsiloxy)methylsilane, monomethacryloxypropyl terminated mono-n-butyl terminated polydimethylsiloxane., methacryloxypropylpentamethyl disiloxane, combinations thereof and the like.

Examples of polysiloxanylalkyl (meth)acrylic monomers include methacryloxypropyl tris(trimethylsiloxy) silane, pentamethyldisiloxanyl methylmethacrylate, and methyldi(trimethylsiloxy)methacryloxymethyl silane. Methacryloxypropyl tris(trimethylsiloxy)silane is the most preferred.

In some embodiments monofunctional polydimethylsiloxanes may be preferred, as they lower not only modulus, but also tan .delta., while bulky silicones, such as those containing at least one branching trimethylsiloxy group will increase tan 67. Accordingly, at least about 30 and preferably at least about 60 weight % of all the silicone components should be non-bulky silicone containing compounds such as polydimethylsiloxanes.

Desirably, silicone hydrogels made according to the invention comprise at least about 20 and preferably between about 20 and 70% wt silicone containing components based on total weight of reactive monomer components from which the polymer is made.

In addition to the monofunctional silicone containing components, multifunctional silicone containing components and/or bulky silicone containing compounds may also be included in amounts which do not impart an undesirably high modulus and/or tan .delta..

One class of silicone-containing components is a poly(organosiloxane) prepolymer represented by formula III:

##STR00003## wherein each A independently denotes an activated unsaturated group, such as an ester or amide of an acrylic or a methacrylic acid or an alkyl or aryl group (providing that at least one A comprises an activated unsaturated group capable of undergoing radical polymerization); each of R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are independently selected from the group consisting of a monovalent hydrocarbon radical or a halogen substituted monovalent hydrocarbon radical having 1 to 18 carbon atoms which may have ether linkages between carbon atoms; R.sup.9 denotes a divalent hydrocarbon radical having from 1 to 22 carbon atoms, and m is 0 or an integer greater than or equal to 1, and preferable 5 to 400, and more preferably 10 to 300. One specific example is .alpha., .omega.-bismethacryloxypropyl polydimethylsiloxane.

Another useful class of silicone containing components includes silicone-containing vinyl carbonate or vinyl carbamate monomers of the following formula:

##STR00004## wherein: Y denotes O, S. or NH; R.sup.Si denotes a silicone-containing organic radical; R denotes hydrogen or methyl; d is 1, 2, 3 or 4; and q is 0 or 1. Suitable silicone-containing organic radicals R.sup.Si include the following: –(CH.sub.2).sub.q.Si[(CH.sub.2).sub.sCH.sub.3].sub.3 –(CH.sub.2).sub.q.Si[OSi((CH.sub.2).sub.sCH.sub.3).sub.3].sub.3

##STR00005## wherein: Q denotes

##STR00006##

Wherein p is 1 to 6; R.sup.10 denotes an alkyl radical or a fluoroalkyl radical having 1 to 6 carbon atoms; e is 0 to 200; q’ is 1, 2, 3 or 4; and s is 0, 1, 2, 3, 4 or 5.

The silicone-containing vinyl carbonate or vinyl carbamate monomers specifically include: 1,3-bis[4-(vinyloxycarbonyloxy)but-1-yl]tetramethyl-disiloxane; 3-(vinyloxycarbonylthio) propyl-[tris (trimethylsiloxy)silane]; 3-[tris(trimethylsiloxy)silyl] propyl allyl carbamate; 3-[tris(trimethylsiloxy)silyl] propyl vinyl carbamate; trimethylsilylethyl vinyl carbonate; trimethylsilylmethyl vinyl carbonate, and

##STR00007##

Another class of silicone-containing components includes polyurethane macromers of the following formulae: (*D*A*D*G).sub.a*D*D*E.sup.1; E(*D*G*D*A).sub.a*D*G*D*E.sup.1 or; E(*D*A*D*G).sub.a*D*A*D*E.sup.1 Formulae IV-VI wherein:

D denotes an alkyl diradical, an alkyl cycloalkyl diradical, a cycloalkyl diradical, an aryl diradical or an alkylaryl diradical having 6 to 30 carbon atoms,

G denotes an alkyl diradical, a cycloalkyl diradical, an alkyl cycloalkyl diradical, an aryl diradical or an alkylaryl diradical having 1 to 40 carbon atoms and which may contain ether, thio or amine linkages in the main chain; * denotes a urethane or ureido linkage; .sub.a is at least 1;

A denotes a divalent polymeric radical of formula:

##STR00008## R.sup.11 independently denotes an alkyl or fluoro-substituted alkyl group having 1 to 0 carbon atoms which may contain ether linkages between carbon atoms; y is at least 1; and p provides a moiety weight of 400 to 10,000; each of E and E.sup.1 independently denotes a polymerizable unsaturated organic radical represented by formula:

##STR00009## wherein: R.sup.12 is hydrogen or methyl; R.sup.13 is hydrogen, an alkyl radical having 1 to 6 carbon atoms, or a –CO–Y–R.sup.15 radical wherein Y is –O–, Y–S– or –NH–; R.sup.14 is a divalent radical having 1 to 12 carbon atoms; X denotes –CO– or –OCO–; Z denotes –O– or –NH–; Ar denotes an aromatic radical having 6 to 30 carbon atoms; w is 0 to 6; x is 0 or 1; y is 0 or 1; and z is 0 or 1.

A preferred silicone-containing component is a polyurethane macromer represented by the following formula:

##STR00010## wherein R.sup.16 is a diradical of a disocyanate after removal of the isocyanate group, such as the diradical of isophorone diisocyanate. Another suitable silicone containing macromer is compound of formula X (in which x+y is a number in the range of 10 to 30) formed by the reaction of fluoroether, hydroxy-terminated polydimethylsiloxane, isophorone diisocyanate and isocyanatoethylmethacrylate.

##STR00011##

Other silicone-containing components suitable for use in this invention include those described is WO 96/31792 such as macromers containing polysiloxane, polyalkylene ether, diisocyanate, polyfluorinated hydrocarbon, polyfluorinated ether and polysaccharide groups. U.S. Pat. Nos. 5,321,108; 5,387,662 and 5,539,016 describe polysiloxanes with a polar fluorinated graft or side group having a hydrogen atom attached to a terminal difluoro-substituted carbon atom. US 2002/0016383 describe hydrophilic siloxanyl methacrylates containing ether and siloxanyl linkanges and crosslinkable monomers containing polyether and polysiloxanyl groups. Any of the foregoing polysiloxanes can also be used as the silicone containing component in this invention.

Hydrophilic monomers are also included in the reactive components used to make the contact lenses of the present invention. The hydrophilic monomers used to make the contact lenses of this invention can be any of the known hydrophilic monomers disclosed in the prior art to make hydrogels.

The preferred hydrophilic monomers used to make the polymer of this invention may be either acrylic- or vinyl-containing. Such hydrophilic monomers may themselves be used as crosslinking agents, however, where hydrophilic monomers having more than one polymerizable functional group are used, their concentration should be limited as discussed above to provide a contact lens having the desired modulus. The term “vinyl-type” or “vinyl-containing” monomers refer to monomers containing the vinyl grouping (–CH.dbd.CH.sub.2) and are generally highly reactive. Such hydrophilic vinyl-containing monomers are known to polymerize relatively easily. “Acrylic-type” or “acrylic-containing” monomers are those monomers containing the acrylic group: (CH.sub.2.dbd.CRCOX) wherein R is H or CH.sub.3, and X is O or N, which are also known to polymerize readily, such as N,N-dimethyl acrylamide (DMA), 2-hydroxyethyl methacrylate (HEMA), glycerol methacrylate, 2-hydroxyethyl methacrylamide, polyethyleneglycol monomethacrylate, methacrylic acid and acrylic acid.

Hydrophilic vinyl-containing monomers which may be incorporated into the silicone hydrogels of the present invention include monomers such as N-vinyl amides, N-vinyl lactams (e.g. NVP), N-vinyl-N-methyl acetamide, N-vinyl-N-ethyl acetamide, N-vinyl-N-ethyl formamide, N-vinyl formamide, with NVP being preferred.

Other hydrophilic monomers that can be employed in the invention include polyoxyethylene polyols having one or more of the terminal hydroxyl groups replaced with a functional group containing a polymerizable double bond. Examples include polyethylene glycol, ethoxylated alkyl glucoside, and ethoxylated bisphenol A reacted with one or more molar equivalents of an end-capping group such as isocyanatoethyl methacrylate (“IEM”), methacrylic anhydride, methacryloyl chloride, vinylbenzoyl chloride, or the like, to produce a polyethylene polyol having one or more terminal polymerizable olefinic groups bonded to the polyethylene polyol through linking moieties such as carbamate or ester groups.

Still further examples are the hydrophilic vinyl carbonate or vinyl carbamate monomers disclosed in U.S. Pat. No. 5,070,215, and the hydrophilic oxazolone monomers disclosed in U.S. Pat. No. 4,910,277. Other suitable hydrophilic monomers will be apparent to one skilled in the art.

More preferred hydrophilic monomers which may be incorporated into the polymer of the present invention include hydrophilic monomers such as DMA, HEMA, glycerol methacrylate, 2-hydroxyethyl methacrylamide, NVP, N-vinyl-N-methyl acrylamide, polyethyleneglycol monomethacrylate, methacrylic acid and acrylic acid with DMA being the most preferred.

The hydrophilic monomers may be present in a wide range of amounts, depending upon the specific balance of properties desired. Amounts of hydrophilic monomer up to about 50 and preferably between about 5 and about 50 weight %, based upon all components in the reactive components are acceptable. For example, in one embodiment lenses of the present invention comprise a water content of at least about 30%, and in another embodiment between about 30 and about 50%. For these embodiments, the hydrophilic monomer may be included in amounts between about 20 and about 50 weight %.

The lenses of the present invention have a dynamic COF less than 0.01. The dynamic COF may be imparted to the contact lens by incorporating a lubricious polymer into the reactive mixture from which the lens will be made, or by coating a lens with a lubricious polymer. Suitable lubricious polymers have a weight average molecular weight of at least about 50,000 Daltons, and in some embodiments greater than about 100,000 Daltons. The molecular weight may be determined via gel permeation chromatography (GPC) using a ViscoGEL GMPWXL Column with a 20/80 methanol/water ratio with a flow rate 1.0 ml/min. at 30.degree. C.

Suitable lubricious polymers will also possess, when polymerized and crosslinked to minor amount, a water content of at least about 70%, preferably at least about 80%. For lubricious polymers which are free radical reactive, a “minor amount” of crosslinking may be effected by polymerizing the monomer(s) from which the polymer is formed with a small amount (such as about 7.5 mmol/100 gram of polymer) of crosslinker (for example, EGDMA). Methods for forming crosslinked polymers which are not free radical reactive will be apparent to those of skill in the art from the disclosure contained herein.

Alternatively, the suitability of a polymer for use as a lubricious polymer may be determined by mixing 10 wt % of the monomer from which the polymer is formed in water at room temperature. Monomers that are soluble under these conditions may be used to form lubricious polymers for use in the contact lenses of the present invention. Specific examples of lubricious polymers include high molecular weight hydrophilic polymers of polyamides, polylactones, polyimides, polylactams and functionalized polyamides, polylactones, polyimides, polylactams, such as DMA functionalized by copolymerizing DMA with a lesser molar amount of a hydroxyl-functional monomer such as HEMA, and then reacting the hydroxyl groups of the resulting copolymer with materials containing radical polymerizable groups, such as isocyanatoethylmethacrylate or methacryloyl chloride. Hydrophilic polymers or prepolymers made from DMA or n-vinyl pyrrolidone with glycidyl methacrylate may also be used. The glycidyl methacrylate ring can be opened to give a diol which may be used in conjunction with other hydrophilic prepolymers in a mixed system. Specific examples of lubricious polymers include but are not limited to poly-N-vinyl pyrrolidone, poly(N-vinyl-N-methylacetamide), poly-N-vinyl-2-piperidone, poly-N-vinyl-2-caprolactam, poly-N-vinyl-3-methyl-2-caprolactam, poly-N-vinyl-3-methyl-2-piperidone, poly-N-vinyl-4-methyl-2-piperidone, poly-N-vinyl-4-methyl-2-caprolactam, poly-N-vinyl-3-ethyl-2-pyrrolidone, and poly-N-vinyl-4,5-dimethyl-2-pyrrolidone, polyvinylimidazole, poly-N-N-dimethylacrylamide, polyvinyl alcohol, polyethylene oxide, poly 2 ethyl oxazoline, heparin polysaccharides, polysaccharides, mixtures and copolymers (including block or random, branched, multichain, comb-shaped or star shaped) thereof where poly-N-vinylpyrrolidone (PVP), poly(N-vinyl-N-methylacetamide) (PVMA) are particularly preferred. Copolymers might also be used such as graft copolymers of PVP or amphiphilic copolymers having hydrophilic and hydrophobic blocks such as those disclosed in U.S. Ser. No. 10/954,560. The lubricious polymer may be incorporated into the lens polymer without chemical bonding, such as is disclosed in US 2003/162,862 and US 2003/125,498 or may be copolymerized into the lens matrix or coated onto the contact lens, by any known method such as premold spin casting, as disclosed, for example, in US 2003/052,424, grafting, soaking the lens in a polymeric solution as disclosed in US 2002/006,521 and U.S. Pat. No. 6,478,423, and the like.

When the lubricious polymer is incorporated into the lens polymer, the lubricious polymer may also comprise polyacrylic acid. However, when the lubricious polymer is coated onto the lens, the lubricious polymer is not polyacrylic acid or poly(N,N-dimethylacrylamide).

Alternatively, the lubricious polymer may be a reactive polymer have a molecular weight as low as 2000. Suitable low molecular weight polymers are disclosed in U.S. Ser. No. 10/954559.

The lubricious polymer is incorporated into or onto the lens in amounts sufficient to provide the desired COF. When the lubricious polymer is incorporated into the lens, it may be included in the reaction mixture in amounts between about 1 to about 15 weight percent, more preferably about 3 to about 15 percent, most preferably about 5 to about 12 percent, all based upon the total of all reactive components.

When the lubricious polymer is coated onto the lens any amount which is sufficient to coat the surface of the lens and provide the desired COF may be used (“coating effective amount”). Generally, the amount of lubricious polymer used may be about 0.001 to about 100, preferably about 0.01 to about 50 and more preferably about 0.01 to about 10 weight percent of the coating solution.

Other monomers that can be present in the reaction mixture used to form the contact lenses of this invention include compatibilizing components, such as those disclosed in US 2003/162,862 and US 2003/2003/125,498, ultra-violet absorbing compounds, medicinal agents, antimicrobial compounds, copolymerizable and nonpolymerizable dyes, release agents, reactive tints, pigments, combinations thereof and the like.

A polymerization catalyst is preferably included in the reaction mixture. The polymerization initiators includes compounds such as lauryl peroxide, benzoyl peroxide, isopropyl percarbonate, azobisisobutyronitrile, and the like, that generate free radicals at moderately elevated temperatures, and photoinitiator systems such as aromatic alpha-hydroxy ketones, alkoxyoxybenzoins, acetophenones, acylphosphine oxides, bisacylphosphine oxides, and a tertiary amine plus a diketone, mixtures thereof and the like. Illustrative examples of photoinitiators are 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1 -one, bis(2,6-dimethoxybenzoyl)-2,4-4-trimethylpentyl phosphine oxide (DMBAPO), bis(2,4,6-trimethylbenzoyl)-phenyl phosphineoxide (Irgacure 819), 2,4,6-trimethylbenzyldiphenyl phosphine oxide and 2,4,6-trimethylbenzoyl diphenylphosphine oxide, benzoin methyl ester and a combination of camphorquinone and ethyl 4-(N,N-dimethylamino)benzoate. Commercially available visible light initiator systems include Irgacure 819, Irgacure 1700, Irgacure 1800, Irgacure 819, Irgacure 1850 (all from Ciba Specialty Chemicals) and Lucirin TPO initiator (available from BASF). Commercially available UV photoinitiators include Darocur 1173 and Darocur 2959 (Ciba Specialty Chemicals). These and other photoinitators which may be used are disclosed in Volume III, Photoinitiators for Free Radical Cationic & Anionic Photopolymerization, 2.sup.nd Edition by J. V. Crivello & K. Dietliker; edited by G. Bradley; John Wiley and Sons; New York; 1998. The initiator is used in the reaction mixture in effective amounts to initiate photopolymerization of the reaction mixture, e.g., from about 0.1 to about 2 parts by weight per 100 parts of reactive monomer. Polymerization of the reaction mixture can be initiated using the appropriate choice of heat or visible or ultraviolet light or other means depending on the polymerization initiator used. Alternatively, initiation can be conducted without a photoinitiator using, for example, e-beam. However, when a photoinitiator is used, the preferred initiators are bisacylphosphine oxides, such as bis(2,4,6-trimethylbenzoyl)-phenyl phosphine oxide (Irgacure 819.RTM.) or a combination of 1-hydroxycyclohexyl phenyl ketone and bis(2,6-dimethoxybenzoyl)-2,4-4-trimethylpentyl phosphine oxide (DMBAPO) ,and the preferred method of polymerization initiation is visible light. The most preferred is bis(2,4,6-trimethylbenzoyl)-phenyl phosphine oxide (Irgacure 819.RTM.).

The reactive components (silicone containing component, hydrophilic monomers, lubricious polymers, and other components which are reacted to form the lens) are mixed together either with or without a diluent to form the reaction mixture. The diluent is selected to solubilize the reactive components. Suitable diluents include include those which possess both a hydrophilic and a hydrophobic nature. It has been found that the hydrophilic nature may be characterized by hydrogen donating ability, using Kamlet alpha values (also referred to as alpha values). The hydrophobic nature of the diluent may be characterized by the Hansen solubility parameter .delta.p. Suitable diluents for the present invention are good hydrogen bond donors and polar. As used herein a “good” hydrogen bond donor, will donate hydrogen at least as readily as 3-methyl-3-pentanol. For certain diluents it is possible to measure the hydrogen bond donating ability by measuring the Kamlet alpha value (or as used herein “alpha value”). Suitable alpha values include those between about 0.05 and about 1 and preferably between about 0.1 and about 0.9.

The diluents useful in the present invention should also be relatively non-polar. The selected diluent should have a polarity sufficiently low to solubilize the non-polar components in the reactive mixture at reaction conditions. One way to characterize the polarity of the diluents of the present invention is via the Hansen solubility parameter, .delta.p. In certain embodiments, the .delta.p is less than about 10, and preferably less than about 6. Suitable diluents are further disclosed in U.S. Ser. No. 60/452898 and U.S. Pat. No. 6,020,445. Classes of suitable diluents include, without limitation, alcohols having 2 to 20 carbons, amides having 10 to 20 carbon atoms derived from primary amines and carboxylic acids having 8 to 20 carbon atoms. In some embodiments, primary and tertiary alcohols are preferred. Preferred classes include alcohols having 5 to 20 carbons and carboxylic acids having 10 to 20 carbon atoms.

Preferred diluents include 3,7-dimethyl-3-octanol, 1-dodecanol, 1-decanol, 1 -octanol, 1 -pentanol, 1 -hexanol, 2-hexanol, 2-octanol, 3-methyl-3-pentanol, 2-pentanol, t-amyl alcohol, tert-butanol, 2-butanol, 1-butanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, ethanol, 3,3-dimethyl-2-butanol, 2-octyl-1 -dodecanol, decanoic acid, octanoic acid, dodecanoic acid, mixtures thereof and the like.

More preferred diluents include 3,7-dimethyl-3-octanol, 1 -dodecanol, 1-decanol, 1-octanol, 1-pentanol, 1-hexanol, 2-hexanol, 2-octanol, 1-dodecanol, 3-methyl-3-pentanol, 1-pentanol, 2-pentanol, t-amyl alcohol, tert-butanol, 2-butanol, 1 -butanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-octyl-1 -dodecanol, mixtures thereof and the like.

Various processes are known for molding the reaction mixture in the production of contact lenses, including spincasting and static casting. Spincasting methods are disclosed in U.S. Pat. Nos. 3,408,429 and 3,660,545, and static casting methods are disclosed in U.S. Pat. Nos. 4,113,224 and 4,197,266. The preferred method for producing contact lenses comprising the polymer of this invention is by the direct molding of the silicone hydrogels, which is economical, and enables precise control over the final shape of the hydrated lens. For this method, the reaction mixture is placed in a mold having the shape of the final desired silicone hydrogel, i.e. water-swollen polymer, and the reaction mixture is subjected to conditions whereby the monomers polymerize, to thereby produce a polymer in the approximate shape of the final desired product. Then, this polymer mixture is optionally treated with a solvent and then water, producing a silicone hydrogel having a final size and shape which are quite similar to the size and shape of the original molded polymer article. This method can be used to form contact lenses and is further described in U.S. Pat. Nos. 4,495,313; 4,680,336; 4,889,664; and 5,039,459, incorporated herein by reference. After producing the silicone hydrogel, the lens be may be coated with a hydrophilic coating. Some methods of adding hydrophilic coatings to a lens have been disclosed in the prior art, including U.S. Pat. Nos. 3,854,982, 3,916,033, 4,920,184, 5,002,794, 5,779,943, 6,087,415; WO 91/04283, and EPO 93/810,399.

The non-limiting examples below further describe this invention.

Test Methods

The dynamic contact angle or DCA, was measured at 23.degree. C., with borate buffered saline, using a Wilhelmy balance. The wetting force between the lens surface and borate buffered saline is measured using a Wilhelmy microbalance while the sample strip cut from the center portion of the lens is being immersed into the saline at a rate of 100 microns/sec . The following equation is used F=2.gamma.p cos .theta. or .theta.=cos.sup.-1(F/2.gamma.p) where F is the wetting force, .gamma. is the surface tension of the probe liquid, p is the perimeter of the sample at the meniscus and .theta. is the contact angle. Typically, two contact angles are obtained from a dynamic wetting experiment–advancing contact angle and receding contact angle. Advancing contact angle is obtained from the portion of the wetting experiment where the sample is being immersed into the probe liquid, and these are the values reported herein. At least four lenses of each composition are measured and the average is reported.

Oxygen permeability was determined by the polarographic method generally described in ISO 9913-1: 1996(E), but with the following variations. The measurement is conducted at an environment containing 2.1% oxygen. This environment is created by equipping the test chamber with nitrogen and air inputs set at the appropriate ratio, for example 1800 ml/min of nitrogen and 200 ml/min of air. The t/Dk is calculated using the adjusted P.sub.O2. Borate buffered saline was used. The dark current was measured by using a pure humidified nitrogen environment instead of applying MMA lenses. The lenses were not blotted before measuring. Four lenses were stacked instead of using lenses of varied thickness. A curved sensor was used in place of a flat sensor. The resulting Dk value is reported in barrers (1 barrer=10.sup.-10 (cm.sup.3 of gas.times.cm.sup.2)/(cm.sup.3 of polymer.times.sec.times.cm Hg). Oxygen transmissibility is oxygen permeability divided by the thickness of the lens. Lens thickness is measured using a micrometer, such as a Reider guage at the center of a hydrated lens, using a flat anvil.

The water content was measured as follows: lenses to be tested were allowed to sit in packing solution for 24 hours. Each of three test lens were removed from packing solution using a sponge tipped swab and placed on blotting wipes which have been dampened with packing solution Both sides of the lens were contacted with the wipe. Using tweezers, the test lens were placed in a weighing pan and weighed. The two more sets of samples were prepared and weighed as above. The pan was weighed three times and the average is the wet weight.

The dry weight was measured by placing the sample pans in a vacuum oven which has been preheated to 60.degree. C. for 30 minutes. Vacuum was applied until at least 0.4 inches Hg is attained. The vacuum valve and pump were turned off and the lenses were dried for four hours. The purge valve was opened and the oven was allowed reach atmospheric pressure. The pans were removed and weighed. The water content was calculated as follows: Wet weight=combined wet weight of pan and lenses-weight of weighing pan Dry weight=combined dry weight of pan and lens-weight of weighing pan

.times..times..times..times..times..times..times..times..times..times..tim- es. ##EQU00001## The average and standard deviation of the water content are calculated for the samples are reported.

Modulus was measured by using the crosshead of a constant rate of movement type tensile testing machine equipped with a load cell that is lowered to the initial gauge height. A suitable testing machine includes an Instron model 1122. A dog-bone shaped sample having a 0.522 inch length, 0.276 inch “ear” width and 0.213 inch “neck” width was loaded into the grips and elongated at a constant rate of strain of 2 in/min. until it broke. The initial gauge length of the sample (Lo) and sample length at break (Lf) were measured. Twelve specimens (either -0.05 or -1.00D) of each composition were measured and the average is reported. Tensile modulus was measured at the initial linear portion of the stress/strain curve. Percent elongation is=[(Lf-Lo)/Lo].times.100.

The dynamic coefficient of friction of the contact lens was measured using a Micro-Tribometer, Model UMT-2 unit, with a pin-on-disk sample mount. The contact lens sample was removed from its packing solution and placed on the tip of the “pin” with the center of the lens on the pin tip and pressed against a highly polished stainless steel disk moving at a constant speed of either 10 or 15 cm/sec. Loads of 3, 5, 10 and 20 g were used. The duration at each load was 25 seconds and all measurements were taken at ambient temperature. The resistant frictional force was measured and was used to calculate the coefficient of friction using the following formula: =(F-f’)/N, where

=coefficient of friction

F=measured frictional force, f+f’

f=actual frictional force

f’=experimental artifacts due lens deformation, such as dehydration and interfacial surface tension forces, elasticity, etc.

N=normal load

Seven lenses were tested for each lens type. The coefficient of friction were averaged and reported

In the examples, the following abbreviations are used.

TABLE-US-00001 SiGMA 2-propenoic acid, 2-methyl-,2-hydroxy-3-[3-[1,3,3,3- tetramethyl-1-[(trimethylsilyl)oxy]disiloxanyl] propoxy]propyl ester DAROCUR 1173 2-hydroxy-2-methyl-1-phenyl propane-1-one DMA N,N-dimethylacrylamide HEMA 2-hydroxyethyl methacrylate mPDMS 800-1000 MW (M.sub.n) monomethacryloxypropyl terminated mono-n-butyl terminated polydimethylsiloxane MAA methacrylic acid Norbloc 2-(2′-hydroxy-5-methacrylyloxyethylphenyl)-2H- benzotriazole CGI 1850 1:1 (wgt) blend of 1-hydroxycyclohexyl phenyl ketone and bis(2,6-dimethoxybenzoyl)-2,4-4-trimethylpentyl phosphine oxide PVP poly(N-vinyl pyrrolidone) (K value 90) Blue HEMA the reaction product of Reactive Blue 4 and HEMA, as described in Example 4 of U.S. Pat. No. 5,944,853 IPA isopropyl alcohol D3O 3,7-dimethyl-3-octanol TEGDMA tetraethyleneglycol dimethacrylate TRIS 3-methacryloxypropyltris(trimethylsiloxy)silane PAA poly(acrylic acid) CGI 819 bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide

EXAMPLE 1

The reaction components and diluent (D30) listed in Table 1 were mixed together until all components were dissolved. The 5 reactive components are reported as weight percent of all reactive components and the diluent is weight percent of final reaction mixture. The reaction mixture was placed into thermoplastic contact lens molds (front molds made from Zeonor.RTM., back molds made from polypropylene) and irradiated at 60.degree. C. with 0.5 mW/cm.sup.2, followed by 1 mW/cm.sup.2 then 3 mW/ cm.sup.2 visible light using Philips TL 20W/03T fluorescent bulbs. The molds were opened and lenses were extracted five times with IPA at ambient temperature for about 2 hours per cycle to remove residual diluent and monomers, placed into borate-buffered saline solution. The physical properties of the lenses (Dk, water content, advancing dynamic contact angle, modulus, elongation and dynamic coefficient of friction) were measured and are shown in Table 3, below.

TABLE-US-00002 TABLE 1 Component Wt % SiGMA 28 PVP (K90) 7 DMA 23.5 MPDMS 31 HEMA 6 Norbloc 2 TEGDMA 1.5 Blue HEMA 0.02 CGI 1850 0.98 % Diluent* 23 Diluent D3O

EXAMPLE 2

The lenses of Example 1 were clinically evaluated against Acuvue.RTM. brand contact lenses. The clincial evaluation, was a randomized, bilateral cross-over study with 39 patients. The lenses were worn in a daily wear mode (nightly removal) for a period of one week using ReNu MultiPlus Multi-Purpose Solution. After 30 minutes and one week of wear for each leris, the patients were asked to rate the lenses for the following: dryness, initial comfort, end of day comfort, overall preference. Each attribute is rated on a visual analog questionnaire form. The form consisted of a visual analog from 0 to 50 with verbal descriptions at specific intervals to explain the scale to the subject (50=excellent, 0=very poor). Lenses, which score above 42 on the scale, are considered good to excellent. A mean difference of five units between the lens types is considered clinically significant. Table 2 shows the preference results from the clinical study.

TABLE-US-00003 TABLE 2 Ex. 1 v. Acuvue .RTM. contact Attribute lenses Overall Preference 23:6 Initial Comfort 21:3 Dryness 20:3 End of Day Comfort 18:3

TABLE-US-00004 TABLE 3 Property Ex 1 – Acuvue .RTM. contact lenses Dk (barrer) 101 21 Center thickness 0.078-0.0.087 0.011 (mm) % H2O 36-37 58 DCA (.degree.) 55-57 82 Modulus (psi) 87 37 Elongation (%) 223 120 COF (@ 10 cm/s) 0.005

EXAMPLE 3

Lenses were made from the formulation in Table 4. The preparation of the macromer used is described in US Patent application 200300052424.

Lenses were formed in using a process similar to that of Example 1, but with TOPAS.RTM. front molds and polypropylene back molds, curing under visible light at 70.degree. C. Lenses were made as above except with the application of a polyHEMA coating to the surfaces of the molds as described in Examples 10-13 of US Patent application 200300052424.

TABLE-US-00005 TABLE 4 Component Wt % Macromer 18 TRIS 14 PVP (K90) 5 DMA 26 MPDMS 28 HEMA 5 Norbloc 2 TEGDMA 1 Blue HEMA 0.02 CGI 1850 1 % Diluent* 20 Diluent D3O

The physical properties of the lenses (Dk, water content, advancing dynamic contact angle, modulus, elongation and dynamic coefficient of friction were measured and are shown in Table 6, below.

EXAMPLE 4

The lenses of Example 3 were clinically evaluated against Acuvue.RTM. brand contact lenses. The clincial evaluation, was a randomized, bilateral cross-over study with 53 patients. The lenses were worn in a daily wear mode (nightly removal) for a period of one week using SoloCare Multi-Purpose Solution. After 30 minutes and one week of wear for each lens, the patients were asked to rate the lenses for the following: dryness, initial comfort, end of day comfort, overall preference. Each attribute is rated on a visual analog questionnaire form. The form consisted of a visual analog from 0 to 50 with verbal descriptions at specific intervals to explain the scale to the subject (50=excellent, 0=very poor). Lenses, which score above 42 on the scale, are considered good to excellent. A mean difference of five units between the lens types is considered clinically significant. Table 5 shows the preference results from the clinical study.

TABLE-US-00006 TABLE 5 Ex. 3 v. Acuvue .RTM. contact Attribute lenses Overall Preference 20:10 Initial Comfort 17:10 Dryness 14:12 End of Day Comfort 16:12

TABLE-US-00007 TABLE 6 Property Ex 3 Acuvue .RTM. contact lenses Dk (barrer) 99 21 Center Thickness 0.064-0.072 0.011 (mm) % H2O 40-41 58 DCA (.degree.) 83-94 82 Modulus (psi) 75 37 Elongation (%) 281 120 COF (@ 10 cm/s) 0.024

EXAMPLE 5

Lenses were made from the formulation indicated in Table 7 in a process similar to that of Example 1.

TABLE-US-00008 TABLE 7 Component Wt % SiGMA 30 PVP (K90) 6 DMA 31 MPDMS 22 HEMA 8.5 Norbloc 1.5 EGDMA 0.8 Blue HEMA 0 CGI 819 0.2 % Diluent* 40 Diluent 29/11 blend of t- amyl alcohol and 2,500 MW PVP

The physical properties of the lenses (Dk, water content, advancing dynamic contact angle, modulus, elongation and dynamic coefficient of friction were measured and are shown in Table 9, below.

EXAMPLE 6

The lenses of Example 5 were clinically evaluated against Acuvue2.RTM. brand contact lenses. The clincial evaluation, was a double masked, bilateral cross-over study with 43 patients. The lenses were worn in a daily wear mode (nightly removal) for a period of two weeks using Complete.RTM. cleaning and disinfection system upon lens removal. After 30 minutes and two weeks of wear for each lens, the patients were asked to rate the lenses for the following: dryness, initial comfort, end of day comfort, overall preference. Each attribute is rated on a visual analog questionnaire form. The form consisted of a visual analog from 0 to 50 with verbal descriptions at specific intervals to explain the scale to the subject (50=excellent, 0=very poor). Lenses, which score above 42 on the scale, are considered good to excellent. A mean difference of five units between the lens types is considered clinically significant. Table 5 shows the preference results from the clinical study.

TABLE-US-00009 TABLE 8 Ex. 5 v. Acuvue2 .RTM. contact Attribute lenses Overall Preference 15:14 Initial Comfort 14:12 Dryness 12:8 End of Day Comfort 12:10

TABLE-US-00010 TABLE 9 Acuvue2 .RTM. contact Property Ex 5 lenses Dk (barrer) 57 21 Center thickness 0.057-0.079 0.084 (mm) % H2O 47-49 58 DCA (.degree.) 33-66 82 Modulus (psi) 66 37 Elongation (%) 258 120 COF (@ 10 cm/s) 0.006

EXAMPLE 7

The lenses of Example 1 were compared to Focus Night & Day.RTM. brand contact lenses (commercially available from Ciba Vision) in a one week, daily wear, bilateral cross-over, randomized, design study. There were 35 patients in the study. The lenses were worn in a daily wear mode (nightly removal) for a period of two weeks using ReNu MultiPlus Multi-Purpose Solution for cleaning upon lens removal. After 30 minutes and one week of wear for each lens, the patients were asked to rate the lenses for the following: dryness, initial comfort, end of day comfort, overall preference. Each attribute is rated on a visual analog questionnaire form. The form consisted of a visual analog from 0 to 50 with verbal descriptions at specific intervals to explain the scale to the subject (50=excellent, 0=very poor). Lenses, which score above 42 on the scale, are considered good to excellent. A mean difference of five units between the lens types is considered clinically significant. Table 10 shows the preference results from the clinical study. Table 11 shows a comparison of physical properties between the lens of Example 1 and the Focus Night and Day brand contact lens.

TABLE-US-00011 TABLE 10 Ex. 1 v. Focus Night and Attribute Day .RTM. contact lenses Overall Preference 25:5 Initial Comfort 25:3 Dryness 18:3 End of Day Comfort 22:5

TABLE-US-00012 TABLE 12 Focus Night and Day .RTM. Property Ex 1 contact lenses Dk (barrer) 107 140 Center thickness 0.088-0.092 NM (mm) % H2O 35-37 24 DCA (.degree.) 48-53 67 Modulus (psi) 86 238 Elongation (%) 250 178 COF (@ 10 cm/s) 0.005 0.049 NM = not measured, but nominal center thickness was reported to be 0.08

EXAMPLE 8

The lenses of Example 1 were compared to PureVision.RTM. brand contact lenses (commercially available from Bausch & Lomb) in a one month, continuous wear, contarlateral, randomized per eye study. There were 26 patients in the study. After 30 minutes and one week of wear for each lens, the patients were asked to rate the lenses for the following: dryness, initial comfort, end of day comfort, overall preference. Each attribute is rated on a visual analog questionnaire form. The form consisted of a visual analog from 0 to 50 with verbal descriptions at specific intervals to explain the scale to the subject (50=excellent, 0=very poor). Lenses, which score above 42 on the scale, are considered good to excellent. A mean difference of five units between the lens types is considered clinically significant. Table 12 shows the preference results from the clinical study. Table 13 shows a comparison of physical properties between the lens of Example 1 and the PureVision and Day brand contact lens.

TABLE-US-00013 TABLE 12 Ex. 1 v. PureVision .RTM. contact Attribute lenses Overall Preference 14:2 Initial Comfort 14:2 Dryness 11:2 End of Day Comfort 13:1

TABLE-US-00014 TABLE 13 PureVision .RTM. contact Property Ex 1 lenses Dk (barrer) 107 79 Center thickness 0.088-0.092 NM (mm) % H2O 35-37 38 DCA (.degree.) 48-53 117 Modulus (psi) 86 155 Elongation (%) 250 286 COF (@ 10 cm/s) 0.005 0.020 NM = not measured, but nominal center thickness was reported to be 0.09

EXAMPLE 9

A clinical study was conducted comparing patient response to the lenses of Example 5, Focus Night and Day.RTM. contact lenses, Acuvue.RTM.2 brand contact lenses and for redness, no contact lens wear. The lenses were worn in a daily wear modality for four weeks. The replacement interval for the Focus Night and Day.RTM. contact lenses was four weeks and the replacement interval for the lenses of Example 5 and the Acuvue.RTM.2 lenses was two weeks. Forty-eight patients who had never worn contact lenses were recruited for the study and randomly assigned to wear on of the three lenses being studied, or no lenses at all. The subjects were not informed of the brand of lens they were evaluated and did not see any lens product packaging. The study was a four cell, parallel, randomized and controlled double masked dispensing study. Optifree Express was used as the lens care solution. For all visits one investigator performed lens related assessments (such as lens fit) and removed the contact lenses (if worn by the subject being evaluated) and another performed redness and lid irritation assessments. In this way, the lens identity was masked from the investigators performing the performance evaluations. Photographs of the patients right eye in each group were taken prior to dispensing the contact lenses and after 1 month. Representative photographs are shown in FIGS. 1 through 4. In each Figure the photograph on the right was the photograph taken prior to lens wear and the photograph on the left was taken at the four month visit. Each visit was conducted at least 2 hours after the patient had woke up that day. FIG. 1 contains the photographs from a blue eyed patient who wore spectacle lenses throughout the study. As can be seen from comparing the photographs in FIG. 1, there is no significant difference in redness in the eyes of this patient.

FIG. 2 contains the photographs from a blue eyed patient who wore lenses of Example 5 throughout the study. As can be seen from comparing the photographs in FIG. 2, there is no significant difference in redness in the eyes of this patient, even after wearing contact lenses on a daily wear basis for a month.

FIG. 3 contains the photographs from a blue eyed patient who wore Focus Night and Day.RTM. contact lenses throughout the study. As can be seen from comparing the photographs in FIG. 3, and particularly the area within the circle, there is a discernable increase in general redness, which manifests itself as increased and more pronounced visible capiliaries in the conjuctiva. General redness, as shown here, may reflect irritation and/or dryness.

FIG. 4 contains the photographs from a blue eyed patient who wore Acuvue.RTM.2 brand contact lenses throughout the study. As can be seen from comparing the photographs in FIG. 4, and particularly the area within the circles, there is a discernable increase in general redness, which manifests itself as increased and more pronounced visible capiliaries in the conjuctiva (circles on the right hand side of the slides). General redness, as shown here, may reflect irritation and/or dryness. There is also an increase in limbal redness, which is shown in the picture on the right as more redness around the limbal ring (lower left circle). An increase in limbal redness may reflect less than optimum concentrations of oxygen is reaching the cornea.

Ratings for limbal redness, lid irritation and overall redness were also collected by the masked investigator, and are shown graphically in FIGS. 5 through 7, respectively. FIGS. 5-7 clearly show that the lenses of Example 5 are superior to Acuvue2 brand contact lenses in all three metrics, and superior to Focus Night and Day.RTM. contact lenses with respect to lid irritation and overall redness.

Survey information from the patients related to duration of daily lens wear and the number of hours lens wear was comfortable, was collected by an independent research organization by phone one week after the initial visit and after the replacement interview (4 weeks for Focus Night and Day.RTM. contact lenses, and two weeks for the lenses of Example 5 and Acuvue.RTM.2 contact lenses. The results of the phone survey are shown in Table 14, below.

TABLE-US-00015 TABLE 14 % reporting comfortable Lens % wore lens .gtoreq.9 hrs wear for .gtoreq.9 hrs Ex. 5 94 87 FND 91 69 AV2 90 77

EXAMPLE 10

2.02 g 1-vinyl-2-pyrrolidnone (NVP), 0.03 g of ethyleneglycol dimethacrylate (EGDMA), and 10 .mu.L of DAROCUR 1173 were combined. The blend was degassed by placing under vacuum for 30 minutes. Polymer was formed by placing 100 .mu.L of the blend into a polypropylene molds under nitrogen and curing with UV light from Phillip’s TL20W/09 bulbs for about 45 minutes. The molds were opened and polymer obtained was released into buffered saline solution at 25.degree. C. The buffered saline was replaced with fresh solution every 30 minutes for a total of three soakings. The water content of the hydrated polymer was determined and is reported in Table 15, below.

EXAMPLES 11-14

The procedure of Example 10 was repeated substituting the monomers listed in Table 15 for NVP. The results are shown in Table 15.

TABLE-US-00016 TABLE 15 Ex. # Monomer H2O % 10 1-Vinyl-2-pyrrolidnone 90.1 .+-. 0.7 11 N’N-Dimethyl acrylamide 81.4 .+-. 0.0 12 Acrylic acid 78.4 .+-. 0.2 13 N-Methyl-N-vinylacetamide 94.7 .+-. 0.4 14 1.41 g HEMA/0.61 g MAA 78.0 .+-. 0.3

1. A method for designing a multifocal lens, comprising the steps of: a.) selecting a resting pupil size; b.) calculating a pupil size when viewing near objects; c.) selecting a ratio of far vision correction area to near vision correction area for a lens; d.) calculating values for the ratio as a function of an add power for viewing near and far objects using the resting and near viewing pupil diameters; and e.) adding an amount of optical convergence to the lens.

2. The method of claim 1, wherein step b.) further comprises (i) determining a total add power required by a lens wearer and (ii) calculating a residual add power.

3. The method of claim 1, wherein the ratio of far vision correction area to near vision correction area ratio is 70 to 30.

4. The method of claim 2, wherein the ratio of far vision correction area to near vision correction area ratio is 70 to 30.

5. A lens according to the method of claim 1.

6. A lens according to the method of claim 2.

7. A lens according to the method of claim 3.

8. A lens according to the method of claim 4.

9. The lens of claim 5, comprising an optic zone having a first zone and second annular zone surrounding the first zone and a horizontal prism having a base oriented in a nasal direction.

10. The lens of claim 6, comprising an optic zone having a first zone and second annular zone surrounding the first zone and a horizontal prism having a base oriented in a nasal direction.

11. The lens of claim 7, comprising an optic zone having a first zone and second annular zone surrounding the first zone and a horizontal prism having a base oriented in a nasal direction.

12. The lens of claim 8, comprising an optic zone having a first zone and second annular zone surrounding the first zone and a horizontal prism having a base oriented in a nasal direction.
Contact Lens Description
FIELD OF THE INVENTION

The invention relates to multifocal ophthalmic lenses. In particular, the invention provides methods for designing contact lenses that provide correction for presbyopia and that take into account pupil size and vergence.

BACKGROUND OF THE INVENTION

As an individual ages, the eye is less able to accommodate, or bend the natural lens, to focus on objects that are relatively near to the observer. This condition is known as presbyopia. Similarly, for persons who have had their natural lens removed and an intraocular lens inserted as a replacement, the ability to accommodate is absent.

Among the methods used to correct for the eye’s failure to accommodate are contact lenses that have more than one optical power. In particular, multifocal contact and intraocular lenses have been developed in which zones of distance and near, and in some cases intermediate, power have been provided. However, no one of the known designs has proven to be widely successful with lens wearers.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS

The invention provides methods for designing a contact lenses, lenses according to the design method, and methods for producing the lenses, which lenses provide presbyopic correction by taking into account pupil size and vergence in their design. The lenses of the invention are advantageous in that their design augments the eye’s accommodative gain, meaning the increase in plus power measured in diopters when the eye responds to an accommodative or convergence stimulus. Additionally, the design takes advantage of the eye’s residual accommodation amplitude, or the total accommodative ability of the eye based on the age and ocular physiology of the individual.

The invention provides a method for the design of a multifocal lens comprising, consisting essentially of, and consisting of: a.) selecting a resting pupil diameter; b.) calculating a pupil diameter when viewing near objects; c.) selecting a ratio of near vision correction area to far vision correction area for a lens; d.) calculating values for the ratio as a function of an add power for viewing near and far objects using the resting and near viewing pupil diameters; and e.) adding an amount of optical convergence for the lens.

In a first step of the method of the design of the lens of the invention, the pupil size is taken into account in the following manner. A resting pupil diameter, or pupil diameter for viewing objects more than about 500 cm from the eye, is selected based on an average of population data or a measurement of an individual’s pupil. The pupil diameter when viewing near objects, or objects less than about 100 cm from the eye, as a function of prescribed add power is then calculated based on the prescribed add power, the residual accommodation and the resting pupil diameter. To perform this calculation, the total add power required by the lens wearer must be determined. A portion of this add power will be supplied by the prescribed add power of the lens and a portion by the residual accommodation of the lens wearer’s eye.

The residual add power may be calculated by subtracting the prescribed add power from the total add power required. A determination of the total amount of add power required will be based on optics, clinical experience that determines add powers for product which powers generally are available in the range from 1.00 to 3.00D, and the known studies of the accommodation needs of presbyopic populations as a function of age. The residual accommodation may be a physiologically determined quantity, mainly dependent on age and typically varies from 10+D for people less than about 15 years of age to less than 0.5D in those more than about 65 years old. For illustration purposes, it may be assumed that, to read clearly at 35 cm from the eye, an individual may require a total add power of 2.85D. The prescribed add power will be 1.00D and the residual add power will be 1.65D.

It is also known that there is a functional dependence between pupil size and accommodation measured at a constant luminance. Based on this, the accommodative response has been computed by obtaining the inverse of the object distance and has been measured over a wide range of light intensities. For example, such data was reported in Glen Myers, Shirin Berez, William Krenz and Lawrence Stark, Am. J. Physiol. Regul. Integr. Comp. Physiol., 258: 813-819 (1990). Such data is the basis for the pupil constriction model that assumes independent linear interaction between accommodative stimulus and increase in luminance as shown by the equation: A=A.sub.0-B-C (I) wherein: A is the pupil size; A.sub.0 is the resting pupil size; B is 1/object distance in meters; and C is log FL. Measured clinically, B is 0.27 and C is 0.19. Assuming a luminance of 1.0 FL, Equation I can be rewritten as: A=A.sub.0-0.27D (II) wherein D is the residual accommodation in the lens wearer’s eye. Applying Equation II to the example above in which 2.85D is the required total add power and assuming a resting pupil diameter of 7.5 mm, Table 1 below shows the calculated values for the difference between the resting pupil diameter and pupil diameter resulting from application of Equation II.

TABLE-US-00001 TABLE 1 Prescribed Residual Reduction in Pupil Size When Add Power Accommodation Pupil Size Viewing Near Objects 1.0D 1.85D 0.50 mm 7.0 mm 1.5D 1.35D 0.36 mm 7.14 mm 2.0D 0.85D 0.23 mm 7.27 mm 2.5D 0.35D 0.09 mm 7.41 mm

The ratio (A.sub.F/A.sub.N) of area of the lens to be used for correcting the wearer’s distance vision, or of the far zone of the lens, versus that used for correcting near vision, or the near vision zone, to be provided by the lens design may be then selected and used to calculate the area of the lens to be allocated to near and far vision optics. The selection may be based on the measured visual acuity and contrast sensitivity at far and near luminance ranges for either an individual or the average for a population of individuals. A preferred ratio for refractive optics is 70/30, in favor of the far vision zones, when viewing near objects. A preferred ratio for a diffractive optic will be 50/50.

The values for A.sub.F/A.sub.N can be calculated as a function of add power for viewing near and far objects, the results for a ratio of 70/30 which are shown on Table 2. The area ratio in this calculation is given by the square of the ratio of diameters.

TABLE-US-00002 TABLE 2 Prescribed Add Power A.sub.F/A.sub.N(Near Objects) A.sub.F/A.sub.N(Far Objects) 1.0D 1.89 (65:35) 2.33 (70/30) 1.5D 2.02 (67:33) 2.33 (70/30) 2.0D 2.13 (68:32) 2.33 (70/30) 2.5D 2.25 (69/31) 2.33 (70/30)

For example, based on a pupil size of 7.5 mm when viewing distant objects and 7.0 mm when viewing near objects, the area of optic provided for far vision is .pi.(7.5/2).sup.2.times.0.70 sq. mm and the area provided for near vision is .pi.(7.5/2).sup.2.times.0.30 sq. mm. When viewing near objects, the area is reduced to .pi.(7.0/2).sup.2. The ratio of the near vision area to the total optical area is .pi.(7.5/2).sup.2.times.0.30/.pi.(7.0/2).sup.2 or (7.5/7.0).sup.2.times.0.30=1.072.times.0.30=1.145.times.0.3=0.343 or 34.3%. Thus, 65.7% remains for the far vision zone.

Thus, the method of the invention permits the lens designer to provide a greater portion of the pupillary aperture to the retinal image of far object images without compromising the luminance of near object images. This is due to the fact that the near vision zone is placed within the pupillary area of the constricted pupil and the far vision zone is disposed within the pupillary aperture of the pupil at rest, or the unaccommodated pupil and pupillary constriction on accommodation excludes some of the far vision zone.

In another step of the method of the invention, an amount of vergence, or optical convergence, effective to bring both eyes of an individual to a common focus on a viewed object is incorporated into the lens. The amount of optical convergence added will depend upon the add power designed into the lens, with the amount of optical convergence increasing as the amount of add power increases. Typically, an amount up to about 2.0D may be added.

The optical convergence preferably is incorporated into the lens by adding a base-in prism, meaning horizontal prism with the base oriented in the nasal direction of the lens. Optical convergence may, in monovision designs, also be incorporated by adding sufficient plus power to the lens to reduce the overall accommodative need. Also, convergence may be added by decentering the center of the near vision zone from the lens’ geometric center.

The preferred lens resulting from the method of the invention is a bifocal in which the optic zone contains two, radially symmetric zones: a first zone that is a central zone and a second zone that is an annular zone that surrounds the central zone. The far and near vision zones are located within the pupillary aperture of the eye at rest. The near vision zone is located within the pupillary aperture when the eye is fully accommodated and has an area of about 30 to about 50% of the area of the optic zone inside of the pupillary aperture for near vision, while the radius of the optic zone matches or exceeds the pupillary aperture for far vision. The ratio of the area of near to far vision is calculated as described above, the ratio favoring far vision when the eye is unaccommodated and near vision when the eye is accommodated. Additionally, the near vision zone is provided with a horizontal prismatic correction with the base oriented in the nasal direction. In the preferred embodiment, the location of the near vision zone is specified to be within the pupillary aperture of the accommodated eye, but no limitation is placed on its location relative to the pupil’s center.

In the lenses of the invention, the optic zone, and the near and far vision zones within, may be on the front surface, or object side surface, the back surface, or eye side surface of the lens, or split between the front and back surfaces. Cylinder power may be provided on the back, or concave surface of the lens in order to correct the wearer’s astigmatism. Alternatively, the cylinder power may be combined with either or both of the distance and near vision powers on the front surface or back surface. In all of the lenses of the invention, the distance, intermediate and near optical powers may be spherical or aspheric powers.

Contact lenses useful in the invention preferably are soft contact lenses. Soft contact lenses, made of any material suitable for producing such lenses, preferably are used. Illustrative materials for formation of soft contact lenses include, without limitation silicone elastomers, silicone-containing macromers including, without limitation, those disclosed in U.S. Pat. Nos. 5,371,147, 5,314,960, and 5,057,578 incorporated in their entireties herein by reference, hydrogels, silicone-containing hydrogels, and the like and combinations thereof. More preferably, the surface is a siloxane, or contains a siloxane functionality, including, without limitation, polydimethyl siloxane macromers, methacryloxypropyl polyalkyl siloxanes, and mixtures thereof, silicone hydrogel or a hydrogel, such as etafilcon A.

A preferred lens-forming material is a poly 2-hydroxyethyl methacrylate polymers, meaning, having a peak molecular weight between about 25,000 and about 80,000 and a polydispersity of less than about 1.5 to less than about 3.5 respectively and covalently bonded thereon, at least one cross-linkable functional group. This material is described in U.S. Pat. No. 6,846,892 incorporated herein in its entirety by reference. Suitable materials for forming intraocular lenses include, without limitation, polymethyl methacrylate, hydroxyethyl methacrylate, inert clear plastics, silicone-based polymers, and the like and combinations thereof.

Curing of the lens forming material may be carried out by any means known including, without limitation, thermal, irradiation, chemical, electromagnetic radiation curing and the like and combinations thereof. Preferably, the lens is molded which is carried out using ultraviolet light or using the full spectrum of visible light. More specifically, the precise conditions suitable for curing the lens material will depend on the material selected and the lens to be formed. Polymerization processes for ophthalmic lenses including, without limitation, contact lenses are well known. Suitable processes are disclosed in U.S. Pat. No. 5,540,410 incorporated herein in its entirety by reference.

The contact lenses of the invention may be formed by any conventional method. For example, the optic zone may be produced by diamond-turning or diamond-turned into the molds that are used to form the lens of the invention. Subsequently, a suitable liquid resin is placed between the molds followed by compression and curing of the resin to form the lenses of the invention. Alternatively, the zone may be diamond-turned into lens buttons.

1. A series of contact lenses, each lens in the series having a targeted optical power within the range of -15 diopters to -6 diopters, each lens in the series comprising an anterior surface having a first central optical zone and an opposite posterior surface having a second central optical zone, wherein one of the first and second central optical zones of each lens in the series is a spherical surface whereas the other is an aspherical surface, wherein the aspherical surface of each lens in the series has a design that, in combination with the spherical surface provides an optical power profile in which lens spherical aberration at 6 mm diameter is from about 0.65 diopter to about 1.8 diopters more negative than spherical aberration at 4 mm diameter.

2. The series of contact lenses of claim 1, wherein the second central optical zones of all the lens in the series are substantially identical to each other.

3. The series of contact lenses of claim 2, wherein the second central optical zone of each lens in the series is a spherical surface.

4. The series of contact lenses of claim 1, wherein the aspherical surface is defined by .times..times..times..alpha..times..alpha..times..alpha..times..alpha..ti- mes..alpha..times..alpha..times..alpha..times. ##EQU00003## in which S.sub.2 is the saggital height, c.sub.2 is the apical curvature (the reciprocal of the apical radius), x is the radial distance from the apex, k.sub.2 is a conic constant, and .alpha..sub.1 to .alpha..sub.7 are the coefficients.

5. The series of contact lenses of claim 4, wherein each lens in the seires has a substantially constant spherical aberration profile.

6. The series of contact lenses of claim 5, wherein the spherical aberration at 6 mm diameter is from about 0.9 diopter to about 1.4 diopters more negative than the spherical aberration at 4 mm diameter.

7. The series of contact lenses of claim 5, wherein the spherical aberration profile is substantially identical to the spherical aberration profile of a spherical lens having a targeted optical power of -6 diopters.
Contact Lens Description
This invention is related to a series of contact lenses. In particular, to a series of contact lenses capable of achieving better lens fitting on an eye and having a controlled spherical aberration incorporated therein.

BACKGROUND

Contact lenses are widely used for correcting defects such as near-sightedness and far-sightedness (myopia and hypermetropia, respectively). Most contact lenses available on the market for correcting myopia or hypermetropia typically have spherical designs, namely, each contact lens having a spherical anterior surface and a spherical posterior surface. Although contact lenses with spherical lens design provide acceptable visual acuity, there are several disadvantages associated with such traditional design. First, a spherical lens design may lead to an inadequate lens fitting on an eye, since human cornea generally has an aspherical surface. Second, a spherical lens design can introduce undesirable spherical aberrations into a lens due to its geometry and thereby decrease visual acuity. By providing a lens surface with asphericity, one may be able to eliminate spherical aberrations. However, by eliminating spherical aberrations of a lens, the optical power profile of a contact lens is inadvertently changed and as such, the apparent optical power at a given aperture (e.g., 4 mm pupil size) of a lens may no longer be the desired and targeted optical power. Such changes in apparent optical powers may greatly hinder a eye-care practitioner to correctly prescribe a contact lens to a patient.

Therefore, there is a need for contact lenses which provide good lens fitting and have controlled lens spherical aberrations.

SUMMARY OF THE INVENTION

The invention provides a series of contact lenses having an optical power ranging from about -15 to about 10 diopters (D). Each lens comprises an anterior surface having a first central optical zone and an opposite posterior surface having a second central optical zone. The first and second central optical zones each are aspherical surfaces. The first central optical zone of each lens has an aspherical design that, in combination with the second central optical zone, provides an optical power profile selected from the group consisting of (1) a substantially constant optical power profile, (2) a power profile mimicking the optical power profile of a spherical lens with identical targeted optical power, and (3) a power profile in which lens spherical aberration at 6 mm diameter is from about 0.65 diopter to about 1.8 diopters more negative than spherical aberration at 4 mm diameter.

The invention also provides a series of aspherical contact lenses having an optical power ranging from about -15 diopters to about -6 diopters, wherein each lens comprises an anterior surface having a first central optical zone and an opposite posterior surface having a second central optical zone. One of the first and second central optical zones is a spherical surface while the other is an aspherical surface. The aspherical surface has a design that, in combination with the spherical surface, provides an optical power profile in which lens spherical aberration at 6 mm diameter is from about 0.65 diopter to about 1.8 diopters more negative than spherical aberration at 4 mm diameter.

The invention further provides method for producing a series of contact lenses of the invention.

These and other aspects of the invention will become apparent from the following description of the preferred embodiments taken in conjunction with the following drawings. As would be obvious to one skilled in the art, many variations and modifications of the invention may be effected without departing from the spirit and scope of the novel concepts of the disclosure.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 schematically shows a spherical aberration profile of a series of contact lenses according to a preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference now will be made in detail to the embodiments of the invention. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents. Other objects, features and aspects of the present invention are disclosed in or are obvious from the following detailed description. It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Generally, the nomenclature used herein and the laboratory procedures are well known and commonly employed in the art. Conventional methods are used for these procedures, such as those provided in the art and various general references. Where a term is provided in the singular, the inventors also contemplate the plural of that term. The nomenclature used herein and the laboratory procedures described below are those well known and commonly employed in the art.

The invention is related to a series of contact lenses having optical power ranging from about -15 to about 10 diopters (D), preferably from about -10 diopters to 10 diopters. Each lens comprises an anterior surface having a first central optical zone and an opposite posterior surface having a second central optical zone. The first and second central optical zones each are aspherical surfaces. The first central optical zone of each lens has an aspherical design that, in combination with the second central optical zone, provides an optical power profile selected from the group consisting of (1) a substantially constant optical power profile, (2) a power profile mimicking the optical power profile of a spherical lens with identical targeted optical power, and (3) a power profile in which lens spherical aberration at 6 mm diameter is from about 0.65 diopter to about 1.8 diopters more negative than spherical aberration at 4 mm diameter.

As used herein, an “aspherical surface” is intended to describe a rotationally symmetrical surface which is not spherical.

A “spherical contact lens” is intended to describe a contact lens having a central optical zone the two opposite surface of which are spherical (i.e., each can be defined by a spherical mathematical function).

A “targeted optical power” in reference to a contact lens means an optical power prescribed by an eye-care practitioner to provide a negative or positive spherical correction. Traditionally, the targeted optical power corresponds to the optical power at the center of a contact lens.

A “optical power profile” or “power profile” in reference to a contact lens is intended to describe variations of optical power from the center to the edge of the central optical zone of the contact lens.

“Spherical aberration” in reference to a lens means that the optical power of the lens varies with the distance from the central axis (diameter), deviates from the ideal optical power (i.e., at the center of the lens), and is rotationally symmetric around the central axis. A negative spherical aberration is intended to describe that the optical power of a lens at any diameter is smaller (or more negative) than the optical power of the lens at the center. A positive spherical aberration is intended to describe that the optical power of a lens at any diameter is larger (or more positive) than the optical power of the lens at the center.

A “spherical aberration profile” in reference to a contact lens is intended to describe variations of spherical aberration from the center to the edge of the central optical zone of the contact lens.

A “substantially constant power profile” in reference to a contact lens is intended to describe a power profile in which spherical aberration at any diameter (distance from the center of the optical zone) within a 6 mm-diameter optical zone is between about -0.1 diopter to about 0.1 diopter.

The second central optical zone of the posterior surface preferably is a conic surface defined by a mathematical function

.times..times..times. ##EQU00001## in which S.sub.1 is the saggital height, c.sub.1 is the apical curvature (the reciprocal of the apical radius), x is the radial distance from the apex, and k.sub.1 is a conic constant. A conic surface may more adequately fit to the topography of the cornea of an eye and may provide a wearer better comfort. More preferably, all of the lens in the series has a common design of the second central optical zone.

The first central optical zone of the anterior surface preferably is a surface defined by

.times..times..times..alpha..times..alpha..times..alpha..times..alpha..tim- es..alpha..times..alpha..times..alpha..times. ##EQU00002## in which S.sub.2 is the saggital height, c.sub.2 is the apical curvature (the reciprocal of the apical radius), x is the radial distance from the apex, k.sub.2 is a conic constant, and .alpha..sub.1 to .alpha..sub.7 are the coefficients.

It is well known to those skilled in the art that the optical power of a contact lens is, inter alia, a function of the index of refraction of the lens material and the algebraic difference between the curvatures of the anterior surface and the posterior surface of the lens. The first central optical zone and the second central optical zone combine to provide an optical power to correct myopia or hypermetropia. Any power profile can be obtained by adjusting one or more of c, k, and .alpha..sub.1 to .alpha..sub.7 in equation (2).

In a preferred embodiment, where a contact lens in the series has a targeted optical power of from 0 to about 10 diopters, it has a substantially constant power profile.

In another preferred embodiment, where a contact lens in the series has a targeted optical power of from about -1 to about -6 diopters, it has a power profile mimicking the optical power profile of a spherical lens with identical targeted optical power.

In a further preferred embodiment, where a contact lens in the series has a targeted optical power of from about -6 diopters to about -15 diopters, preferably from about -6 diopters to about -10 diopters, it has a power profile in which lens spherical aberration at 6 mm diameter is from about 0.65 diopter to about 1.8 diopters, more preferably from about 0.9 to about 1.4, more negative than spherical aberration at 4 mm diameter. Even more preferably, the lens has a constant spherical aberration profile which is substantially identical that of a lens having -6 diopters.

It is discovered that for a piano contact lens or a contact lens with positive optical power, eliminating lens spherical aberration would not change substantially the apparent optical power of the lens while providing a better visual acuity.

It is also discovered that for a contact lens having an optical power of from about -1 to about -6, eliminating lens spherical aberration would decrease significantly (i.e., relatively of percentage of changes) the apparent optical power of the lens at a relatively larger aperture. Such lens may not be able to provide a traditionally defined targeted optical power. Since eye-care practitioners typically prescribe lenses for patients based on the traditional definition of targeted powers, contact lens without spherical aberration and having an targeted optical power of from about -1 diopter to about -10 diopters may not be able to provide a good visual acuity. It is well known that a spherical contact lens having a targeted optical power of from about -1 diopter to about -10 diopters inherently has negative spherical aberrations. Introducing additional negative spherical aberrations into a spherical contact lens for correcting the intrinsic spherical aberration of an human eye may also alter the apparent optical power. Therefore, there is a need for balancing between the need to control lens spherical aberrations and the need to maintain a traditionally defined targeted optical power. It is most beneficial for an aspherical contact lens having an optical power of from about -1 diopter to about -6 diopters to has an optical power profile mimicking (or closely resembling to or substantially identical to) that of a spherical lens having identical targeted optical power.

It is further discovered that for a high minus contact lens (i.e., having an optical power of from about -6 to about -15, better visual acuity could be achieved by introducing a spherical aberration at 4 mm diameter of from about -0.65 to about -1.2 diopters and a spherical aberration at 6 mm diameter of from about -1.6 to about -2.4 diopters. It is believed that a larger population of human eyes generally have a spherical aberration at 4 mm diameter of from about 0.65 to about 1.2 diopters and a spherical aberration at 6 mm diameter of from about 1.6 to about 2.4 diopters. Incorporation of such amount of spherical aberration in a contact lens having a targeted optical power of more negative than -6 diopters may provide a better acuity while causing a tolerable percentage of changes in apparent optical power. Where a lens has a targeted optical power within the range of -1 diopter to -6 diopters, the percentage of changes in apparent optical power may not be tolerable to a patient.

The first and second central optical zones can have a shape of any conventional lens. Preferably, it is circular. More preferably, it is substantially concentric with the central axis. The first and second central optical zones can have identical and different size. Typically, the size of either of the two optical zones can be from about 5 mm to 10 mm in diameter, preferably from about 6 mm to 8 mm in diameter.

In a preferred embodiment, both the first central optical zone on the anterior surface and the second central optical zone on the posterior surface are substantially concentric with a central axis.

It is understood that each lens in the series of contact lenses can have one or more non-optical zones which surround the central optical zone. A person skill in the art will know well how to incorporate a family of common non-optical zones into a lens design.

FIG. 1 schematically illustrates power profiles of a series of contact lenses according to a preferred embodiment. This series of lenses are divided into three sub-series, a first sub-series of lens having an optical power of from about plano (0) to 10 diopters, a second sub-series of lenses having an optical power of from about -1 to about -6 diopters, and a third sub-series of lens having an optical power of from about -7 to -15 diopters. The X-axis represents a distance from the lens center. The Y-axis represents differences in optical power between at any position other than the lens center and at the lens center. The targeted optical powers are plano, -1, -2, -3, -4, -5, and -6 respectively from the top to the bottom in FIG. 1. These power profiles are almost identical to the power profiles of spherical lenses with corresponding targeted optical power. Each lens in the first sub-series has a power profile identical to that of the piano lens. Each lens in the second sub-series has one of the power profile shown in FIG. 1 for a given targeted optical power. Each lens in the third sub-series has a spherical aberration profile substantially identical to that of a lens having an optical power of -6 diopters.

By using an optical computer aided design (CAD) system and a mechanical CAD system, one can design each lens in a series of contact lenses of the invention. An optical CAD system is used to design an optical model lens. “An optical model lens” refers to an ophthalmic lens that is designed in a computer system and generally does not contain other non-optical systems which are parts of an ophthalmic lens. Exemplary non-optical systems of a contact lens include, but are not limited to bevel, peripheral blending zone, peripheral zone, lenticular, and edge that joins the anterior and posterior surfaces of a contact lens.

“A bevel” refers to a non-optical surface zone located at the edge of the posterior surface of a contact lens. Generally, the bevel is a significantly flatter curve and is usually blended with the base curve (optical posterior surface) of a contact lens and appears as an upward taper near the edge. This keeps the steeper base curve radius from gripping the eye and allows the edge to lift slightly. This edge lift is important for the proper flow of tears across the cornea and makes the lens fit more comfortable.

“A lenticular” refers to a non-optical surface zone of the anterior surface of a contact lens adjacent to the edge. The primary function of the lenticular is to control the thickness of the lens edge.

Any known, suitable optical computer aided design (CAD) system may be used to design an optical model lens. Exemplary optical computer aided design systems includes, but are not limited to Advanced System Analysis program (ASAP) from Breault Research Organization and ZEMAX (Focus Software, Inc.). Preferably, the optical design will be performed using Advanced System Analysis program (ASAP) from Breault Research Organization with input from ZEMAX (Focus Software, Inc.).

The design of the optical model lens can be transformed by, for example, a mechanical CAD system, into a mechanical lens design that includes optical zones, non-optical zones and non-optical features. Preferably, when transforming the design of an optimized optical model lens into a mechanical lens design, some common features of a family of contact lenses can be incorporated, such as, for example, bevel, peripheral zone, lenticular, and edge. A peripheral blending zone can be utilized to smoothly blend the central optical zone to non-optical zones on the anterior and posterior surfaces.

Any know, suitable mechanical CAD system can be used in the invention. Preferably, a mechanical CAD system capable of representing precisely and mathematically high order surfaces is used to design a contact lens. An example of such mechanical CAD system is Pro/Engineer.

A series of contact lenses of the invention can be either hard or soft lenses. Soft contact lenses of the invention is preferably made from a soft contact lens material, such as hydrogels. Any known suitable hydrogels can be used in the invention. Preferably, a silicone-containing hydrogel is used in the invention. It will be understood that any lens described above comprising any soft contact lens material would fall within the scope of the invention.

After completing a desired design, contact lenses of the invention can be produced in a computer-controlled manufacturing system. A computer-controlled manufacturing device is a device that can be controlled by a computer system and that is capable of producing directly an ophthalmic lens or an optical tools for producing an ophthalmic lens. Any known, suitable computer controllable manufacturing device can be used in the invention. A computer controllable manufacturing device is preferably a numerically controlled lathe, more preferably a two-axis lathe with a 45.degree. piezo cutter or a lathe apparatus disclosed by Durazo and Morgan in U.S. Pat. No. 6,122,999, herein incorporated by reference in its entirety, even more preferably a numerically controlled lathe from Precitech, Inc., for example, such as Optoform ultra-precision lathes (models 30, 40, 50 and 80) having Variform piezo-ceramic fast tool servo attachment.

Contact lenses of the invention may be produced by any convenient means, for example, such as lathing and molding. Preferably, contact lenses are molded from contact lens molds including molding surfaces that replicate the contact lens surfaces when a lens is cast in the molds. For example, an optical cutting tool with a numerically controlled lathe may be used to form metallic optical tools. The tools are then used to make convex and concave surface molds that are then used, in conjunction with each other, to form the lenses of the invention using a suitable liquid lens-forming material placed between the molds followed by compression and curing of the lens-forming material.

Accordingly, contact lenses according to the invention can be manufactured by providing contact lens molds with two molding surfaces, a first molding surface and a second molding surface. The molds having the first molding surface or the second molding surface, in conjunction with each other, form each of a series of contact lenses, each comprising a concave (posterior) surface having a first central optical zone and a convex (anterior) surface having a second central optical zone, wherein the first central optical zone and the second central optical zone combine to provide a targeted optical power to correct myopia or hypermetropia and an optical power profile selected from the group consisting of (1) a substantially constant optical power profile, (2) a power profile mimicking the optical power profile of a spherical lens with identical targeted optical power, and (3) a power profile in which lens spherical aberration at 6 mm diameter is from about 0.65 diopter to about 1.8 diopters more negative than spherical aberration at 4 mm diameter.

In another aspect, the present invention provides a method for producing a series of contact lenses of the invention. The method comprises the steps of shaping each contact lens in the series by a manufacturing means to have a concave (posterior) surface having a first central optical zone and a convex (anterior) surface having a second central optical zone, wherein the first central optical zone and the second central optical zone combine to provide a targeted optical power to correct myopia or hypermetropia and an optical power profile selected from the group consisting of (1) a substantially constant optical power profile, (2) a power profile mimicking the optical power profile of a spherical lens with identical targeted optical power, and (3) a power profile in which lens spherical aberration at 6 mm diamter is from about 0.65 diopter to about 1.8 diopters more negative than spherical aberration at 4 mm diameter.

The contact lenses of the invention can have better lens fitting on an eye and have controlled spherical aberration profile.

The invention is also related to a series of aspherical contact lenses having an optical power ranging from about -15 diopters to about -6 diopters, wherein each lens comprises an anterior surface having a first central optical zone and an opposite posterior surface having a second central optical zone. One of the first and second central optical zones is a spherical surface while the other is an aspherical surface. The aspherical surface has a design that, in combination with the spherical surface, provides an optical power profile in which lens spherical aberration at 6 mm diameter is from about 0.65 diopter to about 1.8 diopters more negative than spherical aberration at 4 mm diameter.

The invention has been described in detail, with particular reference to certain preferred embodiments, in order to enable the reader to practice the invention without undue experimentation. A person having ordinary skill in the art will readily recognize that many of the previous components, compositions, and/or parameters may be varied or modified to a reasonable extent without departing from the scope and spirit of the invention. Furthermore, titles, headings, example materials or the like are provided to enhance the reader’s comprehension of this document, and should not be read as limiting the scope of the present invention. Accordingly, the invention is defined by the following claims, and reasonable extensions and equivalents thereof.

1. A method of cleaning contact lenses using a container with ultrasonic means, housing means and timing means, said container having an aqueous medium in said housing means for suspending a liquid impermeable contact lens storage case, said contact lens storage case housing at least one contact lens suspended in an aqueous medium within said contact lens storage case, said timing means regulating said ultrasonic means, cleaning said contact lens within said contact lens storage case by ultrasonic vibration wherein said aqueous medium surrounding said contact lens within said impermeable contact lens storage case is contact lens solution, saline, cleaner or contact lens cleaning and disinfecting solution and said container houses said aqueous medium in said housing means that is water; and wherein said impermeable contact lens storage case is suspended in a free-floating manner in the water within said container.

2. The method of cleaning in claim 1 where said ultrasonic vibration cleans said contact lens case.

3. The method of cleaning in claim 1 where said container has ultrasonic means of at least 50 Hz and 20 watts.

4. A method of cleaning a contact lens comprising: a) placing a contact lens in a contact lens storage case with contact solution; b) sealing the contact lens storage case with the contact lens therein; c) placing the contact lens case in a sonicator with water wherein the lens case is suspended in a free-floating manner in the water d) sonicating the water, contact lens case, contact solution, and contact lens; and e) removing said contact lens case from the sonicator; wherein said contact lens case is a liquid impermeable contact lens storage case and said sonicator operates at least 50 Hz and 20 watts.

5. The method of claim 4, wherein said contact solution is saline solution.

6. The method of claim 4, wherein said contact solution is cleaning and disinfecting solution.
Contact Lens Description
BACKGROUND

There are many techniques for cleaning and sterilizing contact lenses. Contact lenses continue to be fragile and collect surface contaminants that diminish the visual capacity and useful nature of the contact lenses. Statistics show that the majority of contact lens wearers do not comply with proper cleaning and handling of contact lenses. This new method of cleaning facilitates the cleaning and disinfecting process and improves the visual clarity of the lenses for the wearer, for the recommended life of the contact lenses, in a manner that is simple, economical and quick.

Some wearers of contact lenses bypass the various cleaning processes by purchasing new lenses that are worn a few days and then disposed. This system is good for contact lens manufacturers but wasteful and expensive for the wearer.

Other wearers scrub their lenses with their fingers or use non-scrub cleaners and enzymatic drops or enzymatic soaking tablets to try to clean their contact lenses. These chemicals are costly, can be difficult to remove from the surface of the lenses and irritating to the eyes of the wearer. They can contribute to allergic reactions and eye infections. Some of the enzymatic cleaners are made from porcine pancreatic enzymes, which are against dietary laws for some wearers. Often during the cleaning process, the wearers can have the misfortune of tearing their lenses because of excess handling. Dissatisfaction with these processes of cleaning contact lenses has helped to fuel the disposable line of lenses. Surface contaminants on contact lenses can be from external sources like dirty fingers, air borne particles or from eye discharge that can consist of protein deposits or lipid and mucoid products produced by tears. Bacteria and fungal deposits have been found on contact lenses. In the lab, scientists have been unable to reproduce fungal growth on contact lenses. In April of 2006, there was a fungal outbreak among contact lens wearers, and in November 2006, there was a bacterial outbreak in some lens cleaners that had to be recalled. This method of cleaning, because of its simplicity and effectiveness can help contact lens wearers remove unhealthy contaminants on the surface of the contact lenses. This consequently, improves the clarity of the contact lenses for the recommended life of the particular type of contact lenses, and also protects the vision of the wearers.

The use of ultrasonic waves and other cleaning techniques for contact lenses has been described in the following relevant patents.

U.S. Pat. No. 3,720,402 Cummins, describes cleaning contact lenses in a “foraminous” container within a beaker filled with saline that heats and uses ultrasonic and timing means. The process of cleaning in this manner takes two hours.

U.S. Pat. No. 3,851,861 Cummins, describes an ultrasonic cleaning device that switches off above 75 degrees centigrade, to prevent damage to the lens and the heat shortens the cleaning cycle to 15-30 minutes.

U.S. Pat. No. 3,973,3760 Browning et al, uses a membranous contact lens capsule mounting to a receptacle in contact with a tuner or to a transducer element with ultrasonic means and has a 2-minute ultrasonic cycle followed with a 20-minute disinfecting cycle.

U.S. Pat. No. 4,382,824 Halleck cleans using a combination of ultrasonic waves with a heated bath.

U.S. Pat. No. 4,607,652 Yung, describes a small battery powered ultrasonic device portable and with a removable contact lens case that fits into a cavity contained within the device that operates at a frequency of 20-40 kHz. According to the inventor, the resonance of the ultrasonic apparatus helps to sterilize the contact lenses.

U.S. Pat. No. 4,697,605 Yung uses the waste heat generated by the device described in the previous patent to heat the cleaning liquid in the cavity of the device.

U.S. Pat. No. 4,991,609 Browning, uses an ultrasonic and heating method for cleaning toothbrushes with filter means to allow separation of particulate matter followed by a 30-minute heat cycle at 65 degrees centigrade.

U.S. Pat. No. 5,129,410 Ifejika describes a rotating agitating device operating at a frequency of 10-100 Hz using electromagnetic reciprocating means to produce high energy vibrations to shake lenses clean in a rotational or linear method.

U.S. Pat. No. 6,183,705 Ching-Tsiai Chang, describes suspending contact lenses in a cleaning cup that fits into a chamber that provides ultrasonic and heating means and has a 20-30 minute cleaning cycle. The contact lenses are covered with a grille that allows the substance adhering to the lenses to be removed and to settle to the bottom of the cleaning medium. The heating means follow the ultrasonic cleaning means.

U.S. Pat. No. 6,193,806 Reed, uses a torsion spring that causes high amplitude vibrations to dislodge contaminants of the surface of the lenses.

There are several patents in the prior art that describe the use of ultrasonics as a cleaning method for metals and other hard surface materials. Ultrasonics has also been described in the literature as a method of cleaning hard plastics. It has been described as effective for metals, glass, ceramic and dense plastics and ineffective for soft materials like rubber, Styrofoam, and soft stones like pearls and opals. In directions for operating jewelry sonicators, consumers are specifically advised not to put soft stones like pearls in the cleaners that operate at 20 watts or higher power because of cracking and discoloration that can happen.

This method of cleaning contact lenses using ultrasonic waves, is distinguished from prior art because it is simple, works well with water and only requires a small amount of sterile saline or a small amount of contact lens solution. This method takes only a few minutes of time and is economical after the initial purchase of the ultrasonic device. This method can accommodate all varieties of store bought standard nonporous contact lens containers. When the Bradford protein analysis, a dye technique to determine protein deposits, is tested with this method, the contact lenses remain protein free. Additionally, this method helps to keep the contact lens storage container clean. This method is suited for people who develop allergic reactions to chemicals found in over the counter contact lens cleaning and disinfecting solutions and wetting drops. This method is successful without relying on a subsequent heating cycle. This method is successful with `soft` lenses because the lenses are protected during the ultrasonic process, by floating in a cushion of liquid within their liquid impermeable lens container.

SUMMARY OF THE INVENTION

The present invention relates to a method for the ultrasonic cleaning of contact lenses. An ultrasonic cleaning device with a housing for an aqueous liquid is filled with a suitable aqueous medium such as water to a fill level that allows for free movement of a standard two chambered liquid impermeable contact lens case. With the elimination of the need to have the contact lens container conform to a fitted compartment within the ultrasonic unit, the design of the ultrasonic unit is simplified, various ultrasonic units readily available can be utilized and accommodation of all sizes and shapes of contact lens cases is allowed. For this method, the contact lenses are removed from the wearers eyes and placed in the respective left and right chambers of the standard lens case, then an aqueous medium such as sterile saline or contact lens solution is added to cover the contact lenses. The covers of the standard lens chambers are tightened over each chamber so the contact lenses are secured within the contact lens case. The contact lens case is now liquid impermeable and buoyant. The contact lens case is suspended in a free-floating manner in the aqueous housing of the ultrasonic device. The ultrasonic device operates at a frequency of 60 hz and produces at least 20 watts for a six-minute time span. Units operating at lower frequencies and producing less wattage do not clean contact lenses effectively. The ultrasonic device may operate at a higher frequency with success. At a maximum frequency of 50-60 hz and 117 watts, the contact lenses can be cleaned with a shortened time span of one minute. The ultrasonic device can be compact in nature, as long as free movement of the floating contact lens storage container is permitted. This cleaning method has been determined by experimenting with several different types of jewelry ultrasonic cleaners for home use and with ultrasonic cleaners manufactured for industry use. It has been determined that the store bought jewelry cleaning unit model SI414 designed by SHARPER IMAGE stores, which operates at 60 Hz and 20 watts can clean contact lenses in a 5-6 minute cycle. It has also been determined that other home jewelry cleaners like the PREMIER Princess Electro-Sonic Jewelry cleaner which operates at 8 watts are ineffective at cleaning contact lenses with this method. The company BRANSONIC makes several models of ultrasonic cleaners of varying shapes and sizes for industry use. Model B220 operates at 50-60 Hz and 117 watts and cleans effectively in a 1-minute cycle. There are several ultrasonic units readily available for purchase that allow for rapid cleaning of contact lenses that are manufactured by various companies. The ultrasonic device for this method of use has a switch that turns on the ultrasonic device with timing means so that the ultrasonic vibrations turn off when the timing means reach zero. This is a standard feature of most ultrasonic devices. When ultrasonic vibrations are completed, the wearer can put fresh sterile saline or fresh cleaning solution in the contact lens container or leave the lenses as they are and wear them at a later time. This simple method cleans contact lenses in an efficient, economical manner, prolonging the life of the contact lenses and the comfort of the wearer. This method also helps to keep the contact lens storage case clean. This method when used with sterile saline only, without chemicals, is hypoallergenic and suited for people who develop allergies to the various over the counter contact lens chemical storage solutions and cleaning liquids.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a top view of the invention with contact lens case suspended in an aqueous medium within the housing of an ultrasonic device.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is a process for cleaning contact lenses. The contact lenses are placed within their respective lens chambers 5 in a standard liquid impermeable contact lens storage case 1, The contact lenses are then covered with an aqueous medium such as sterile saline or contact lens cleaning and disinfecting solution. The right and left corresponding liquid impermeable covers of the filled contact lens chambers 5 are placed over their respective chambers 5 and securely fastened so the lenses are housed in a buoyant liquid impermeable manner. The contact lens case 1, is then placed in the housing 2 of ultrasonic device 3, said housing being filled with an aqueous medium 4, preferably water, so said aqueous medium 4 completely surrounds and suspends said contact lens case 1. Said ultrasonic device 3 having timing means 6, which activate ultrasonic waves that vary in strength depending on the power of said ultrasonic device 3, with the minimal frequency and power of 50-60 Hz and 20 watts, cleaning in a six minute cycle and the maximum frequency of 60 Hz and 117 watts cleaning in a one minute cycle. Said timing means 6, functioning by both turning on said ultrasonic device 3 and automatically turning off said ultrasonic device 3 after set time has expired. Said contact lens case 1 is removed from aqueous medium 4 and can be left undisturbed until ready to wear, or the right and left corresponding nonporous covers of the filled contact lens chambers 5, can be removed and the chambers 5 can be refilled with new sterile saline or contact lens cleaning and disinfecting solution, and then recovered until ready to use.

1. A toric contact lens, comprising an optical axis, an anterior surface having a first optical zone, and an opposite posterior surface having a second optical zone, wherein one of the first optical zone or the second optical zone is a toroidal surface whereas the other zone is non-toroidal surface which is a spherical surface or an aspheric surface, wherein the toroidal and non-toroidal surfaces combine to provide a targeted cylindrical optical power and a targeted spherical optical power, wherein at least one of the first and second optical zone has an aspherical surface which is designed to provide, in combination with the surface of the other optical zone, a controlled optical power profile which is substantially rotationally-symmetric with respect to the optical axis or incorporates a spherical aberration component, wherein the spherical aberration component is described by any one of fourth order, sixth order, eighth order Zernike spherical aberration-like terms and has a spherical aberration value of from about -0.5 diopter to about -1.5 diopters at a distance of 3 mm from the optical axis.

2. The toric contact lens of claim 1, wherein the controlled optical power profile is substantially rotationally-symmetric with respect to the optical axis.

3. The toric contact lens of claim 1, wherein the controlled optical power profile incorporates a spherical aberration component, wherein the spherical aberration component is described by any one of fourth order, sixth order, eighth order Zernike spherical aberration-like terms and has a spherical aberration value of from about -0.5 diopters to about -1.5 diopters.

4. The toric contact lens of claim 1, wherein the lens has an optical power deviation of from about -0.8 diopters to about -1.1 diopters at a distance of 3 mm from the optical axis.

5. The toric contact lens of claim 1, wherein the toroidal surface is formed by defining a curve in the Y-Z plane and then rotating this curve around an axis parallel to the Y-axis from a distance r, wherein the Z-axis passes through the apex of the curve in normal direction, wherein the value of the distance r is selected based on the targeted cylindrical optical power, wherein the curve is defined by any mathematic function to provide the targeted spherical optical power.

6. The toric contact lens of claim 5, wherein the curve is defined by Equation 1 or 2 .times..times..times..times..alpha..times..alpha..times..alpha..times..al- pha..times..alpha..times..alpha..times..alpha..times. ##EQU00003## in which c is the curvature (the reciprocal of the radius), k is a conic constant and .alpha..sub.1 to .alpha..sub.7 are the coefficients. The value of the distance r can be selected to impart a desired cylindrical optical power to the contact lens for correcting astigmatism errors of an eye.

7. The toric contact lens of claim 1, wherein the toroidal surface is defined by Equation 3 .times..times..times..times..times..times. ##EQU00004## where c.sub.x and c.sub.y are the curvatures at x and y meridians, k.sub.x and k.sub.y are conic constants, and Z-axis passes through the apex of the surface.

8. The toric contact lens of claim 1, wherein the optical axis of a contact lens coincides with the central axis which passes through the geometrical centers of the anterior and posterior surfaces.

9. The toric contact lens of claim 1, wherein the optical axis coincides substantially with the line-of-sight (LOS) of an eye.

10. The toric contact lens of claim 1, wherein the non-toroidal surface comprises a central circular area having a diameter of from about 2.0 mm to about 3.5 mm and an annular region surrounding the central circular area, wherein the central circular area and the annular region are concentric with the optical axis, wherein the toroidal and non-toroidal surface combine together to provide a targeted cylindrical optical power to correct astigmatism vision errors and a multifocal spherical optical power to compensate for presbyopia.

11. The toric contact lens of claim 10, wherein the central circular area is a progressive power addition zone for near vision correction and optionally for intermediate vision correction, wherein the annular region surrounding the central circular area is a distance vision zone.

12. A series of toric contact lenses, each having a targeted spherical optical power of from about -15 diopters to about 10 diopters and a targeted cylindrical optical power, wherein each contact lens in the series has an optical axis, an anterior surface having a first optical zone, and an opposite posterior surface having a second optical zone, wherein one of the first and second optical zones is a toroidal surface whereas the other optical zone is a non-toroidal spherical or aspherical surface, wherein the surface of at least one of the first and second optical zone is designed to provide, in combination with the surface of the other optical zone, provide a controlled optical power profile in which (1) the optical power deviations of the lens are substantially constant; (2) power deviation at a distance of 3 mm from the optical axis is from about -0.5 diopter to about -1.5 diopters; (3) power deviation at a distance of 3 mm from the optical axis is from about 0.2 diopter to about 1.0 diopter smaller than power deviations at a distance of 2 mm from the optical axis; or (4) there is a spherical aberration component described by any one of fourth order, sixth order, eighth order Zernike spherical aberration-like terms, or combination thereof, wherein the spherical aberration component has a value of -0.5 diopter to about -1.5 diopters at a distance of 3 mm from the optical axis.

13. The series of toric contact lenses of claim 12, wherein each lens in the series is substantially free of optical power deviations.

14. The series of toric contact lenses of claim 12, wherein each lens in the series has power deviation of from about -0.5 diopter to about -1.5 diopters at a distance of 3 mm from the optical axis.

15. The series of toric contact lenses of claim 12, wherein, for each lens, power deviation at a distance of 3 mm from the optical axis is from about 0.2 diopter to about 1.0 diopter smaller than power deviations at a distance of 2 mm from the optical axis.

16. The series of toric contact lenses of claim 12, wherein the controlled optical power profile incorporates a spherical aberration component described by any one of fourth order, sixth order, eighth order Zernike spherical aberration-like terms, or combination thereof, wherein the spherical aberration component has a value of -0.5 diopter to about -1.5 diopters at a distance of 3 mm from the optical axis.

17. The series of toric contact lenses of claim 12, wherein the optical power deviation profile of each lens in the series are substantially rotationally-symmetric, wherein each lens having a targeted spherical optical power of from 0 to about 15 diopters is substantially free of optical power deviation; each lens having a targeted spherical optical power of from about -1.0 diopter to about -6.0 diopters has a power deviation profile mimicking that of a spherical lens with identical targeted spherical optical power; and each lens having a targeted spherical optical power of from about -6.0 diopter to about -15.0 diopters has a controlled optical power profile in which power deviation at a distance of 3 mm from the optical axis is from about 0.2 diopters to about 1.0 diopter less than the optical power deviation at a distance of 2 mm from the optical axis.

18. The series of toric contact lenses of claim 12, wherein all lenses in the series have one substantially identical power deviation profile in which power deviation at a distance of 3 mm from the optical axis is from about -0.5 diopters to about -1.5 diopters.

19. The series of toric contact lenses of claim 12, wherein all lenses in the series have a substantially identical power deviation profile in which power deviation at a distance of 3 mm from the optical axis is from about 0.2 diopters to about 1.0 diopter less than the power deviation at a distance of 2 mm from the optical axis.

20. The series of toric contact lenses of claim 12, wherein all lenses in the series have a substantially identical spherical aberration component which has a spherical aberration value of -0.5 diopter to about -1.5 diopters, preferably from about -0.8 diopters to about -1.1 diopters, at a distance of 3 mm from the optical axis.

21. The series of toric contact lenses of claim 12, wherein all lenses in the series have a substantially identical spherical aberration component in which spherical aberration value at a distance of 3 mm from the optical axis is from about 0.2 diopters to about 1.0 diopter smaller than that at a distance of 2 mm from the optical axis.

22. The series of toric contact lenses of claim 12, wherein the non-toroidal surface comprises a central circular area having a diameter of from about 2.0 mm to about 3.5 mm and an annular region surrounding the central circular area, wherein the central circular area and the annular region are concentric with the optical axis, wherein the non-toroidal surface and the toroidal surface combine together to provide a targeted cylindrical optical power to correct astigmatism vision errors and a multifocal spherical power to compensate for presbyopia.

23. The series of toric contact lenses of claim 12, wherein the toroidal surface is formed by defining a curve in the Y-Z plane and then rotating this curve around an axis parallel to the Y-axis from a distance r, wherein the Z-axis passes through the apex of the curve in normal direction, wherein the value of the distance r is selected based on the targeted cylindrical optical power, wherein the curve is defined by any mathematic function to provide the targeted spherical optical power.

24. The series of toric contact lenses of claim 23, wherein the curve is defined by Equation 1 or 2 .times..times..times..times..alpha..times..alpha..times..alpha..times..al- pha..times..alpha..times..alpha..times..alpha..times. ##EQU00005## in which c is the curvature (the reciprocal of the radius), k is a conic constant and .alpha..sub.1 to .alpha..sub.7 are the coefficients. The value of the distance r can be selected to impart a desired cylindrical optical power to the contact lens for correcting astigmatism errors of an eye.

25. The series of toric contact lenses of claim 12, wherein the toroidal surface is defined by Equation 3 .times..times..times..times..times..times. ##EQU00006## where c.sub.x and c.sub.y are the curvatures at x and y meridians, k.sub.x and k.sub.y are conic constants, and Z-axis passes through the apex of the surface.

26. The series of toric contact lenses of claim 12, wherein the optical axis of a contact lens is the central axis which passes through the geometrical centers of the anterior and posterior surfaces.

27. The series of toric contact lenses of claim 12, wherein the optical axis coincides substantially with the line-of-sight (LOS) of an eye.
Contact Lens Description
This invention is related to contact lenses. In particular, the present invention is related to toric contact lenses having a cylindrical optical surface (or power) to correct astigmatism vision errors and a controlled optical power profile that provides improved vision correction.

BACKGROUND

Contact lenses are widely used for correcting many different types of vision deficiencies. These include defects such as near-sightedness and far-sightedness (myopia and hypermetropia, respectively), astigmatism vision errors, and defects in near range vision usually associated with aging (presbyopia).

Astigmatism is optical power meridian-dependent refractive error in an eye. This is usually due to one or more refractive surfaces, most commonly the anterior cornea, having a toroidal shape. It may also be due to one or more surfaces being transversely displaced or tilted. Astigmatism is usually regular, which means that the principal (maximum and minimum power) meridians are perpendicular to each other. People with astigmatism have blurred vision at all distances, although this may be worse at distance or near, depending on the type of astigmatism. These people may complain of sore eyes and headaches associated with demanding visual tasks. Astigmatism can be corrected with a toric contact lens, which usually has one spherical surface and one toroidal (cylindrical) surface which can be formed in either the posterior surface (back surface) or in the anterior surface (front surface) of the toric lens. Since astigmatism requiring vision correction is usually associated with other refractive abnormalities, such as myopia (nearsightedness) or hypermetropia (farsightedness), toric contact lenses are generally prescribed also with a spherical power correction to correct myopic astigmatism or hypermetropic astigmatism.

A conventional toric contact lens with one toroidal surface and one spherical surface typically will have an uncontrolled optical power profile. The optical power at any given position of the toric lens depends not only upon the distance from the optical axis (or lens center) but also upon angular position relative to the principal meridians of the toric lens. In addition, the optical power profile of a toric lens is dependent upon its targeted optical powers (i.e, Rx). The optical power of a toric lens can be composed of purely positive power deviations (i.e., the power at a position depart from the lens center being larger than the power at the lens center), purely negative power deviations (i.e., the power at a position depart from the lens center being less than the power at the lens center), or the combination of both, depending on the spherical optical power and the cylindrical optical power of the lens. With such uncontrolled optical power profile, a toric lens may not provide optimal vision to a patient, especially with a larger pupils.

Moreover, the spherical aberration can be an inherent high order aberration component of an eye. The spherical aberration generally is a rotationally symmetric aberration around the optical axis. A typical adult human eye, as a result of the optical characteristics of the cornea and crystal lens, inherently exhibits an increasing amount of spherical aberration (positive spherical aberration) as the diameter of the pupil expands. Typically, the spherical aberration, of an adult, is about one diopter at a 6 mm diameter pupil, while the spherical aberration is slightly less than two diopters at an 8 mm pupil. A toric lens with purely positive power deviation may not compensate but instead accentuate the inherent spherical aberration of an eye and as such, may not be able to provide a good vision to a patient with a relative large pupil or under a dark illumination condition (i.e., with a dilated pupil).

Therefore, it is advantageous that a toric lens is designed to have a controlled optical power profile, which is preferably capable of compensating the inherent spherical aberration of a typical human eye, so as to provide an improved vision to a patient.

An object of the invention is to provide a toric contact lens having a controlled optical power profile.

Another object of the invention is to provide a method for producing a toric contact lens having a controlled optical power profile.

A further object of the invention is to provide a family of contact lenses having a series of different cylindrical powers and a series of different spherical powers. Each lens in the series has a controlled optical power profile.

SUMMARY OF THE INVENTION

In accomplishing the foregoing, there is provided, in accordance with one aspect of the present invention, a toric contact lens having a controlled power profile. A toric contact lens of the invention has an optical axis, an anterior surface having a first optical zone, and an opposite posterior surface having a second optical zone. The first optical zone and the second optical zone combine to provide a targeted cylindrical optical power and a targeted spherical optical power. At least one of the first and second optical zone has an aspherical surface which is designed to provide, in combination with the surface of the other optical zone, a controlled optical power profile which is substantially rotationally-symmetric with respect to the optical axis or incorporated a spherical aberration component, wherein the spherical aberration component is described by any one of fourth order, sixth order, eighth order Zernike spherical aberration-like terms and has a value of -0.5 diopter to about -1.5 diopters at a distance of 3 mm from the optical axis.

The invention, in another aspect, provides a family of toric contact lenses having a series of different targeted cylindrical optical powers and a series of different targeted spherical optical powers, wherein each contact lens in the series has an optical axis, an anterior surface having a first optical zone, and an opposite posterior surface having a second optical zone, wherein one of the first and second optical zones is a toroidal surface whereas the other optical zone is a non-toroidal spherical or aspherical surface, wherein the surface of at least one of the first and second optical zone is designed to provide, in combination with the surface of the other optical zone, provide a controlled optical power profile in which (1) the optical power deviations of the lens are substantially constant; (2) power deviation at a distance of 3 mm from the optical axis are from about -0.5 diopter to about -1.5 diopters; (3) power deviation at a distance of 3 mm from the optical axis is from about 0.2 diopter to about 1.0 diopter smaller than power deviations at a distance of 2 min from the optical axis; or (4) there is a spherical aberration component described by any one of fourth order, sixth order, eighth order Zernike spherical aberration-like terms, or combination thereof, wherein the spherical aberration component has a value of -0.5 diopter to about -1.5 diopters at a distance of 3 mm from the optical axis.

The invention, in other aspects, provides a method for producing a toric contact lens of the invention or a series of toric contact lenses of the invention.

These and other aspects of the invention will become apparent from the following description of the preferred embodiments taken in conjunction with the following drawings. As would be obvious to one skilled in the art, many variations and modifications of the invention may be affected without departing from the spirit and scope of the novel concepts of the disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference now will be made in detail to the embodiments of the invention. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents. Other objects, features and aspects of the present invention are disclosed in or are obvious from the following detailed description. It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Generally, the nomenclature used herein and the laboratory procedures are well known and commonly employed in the art. Conventional methods are used for these procedures, such as those provided in the art and various general references. Where a term is provided in the singular, the inventors also contemplate the plural of that term. The nomenclature used herein and the laboratory procedures described below are those well known and commonly employed in the art.

As used herein, an “aspheric surface” is intended to describe a non-spherical surface.

A “spherical contact lens” is intended to describe a contact lens having an optical zone the two opposite surfaces of which are spherical (i.e., each can be defined by a spherical mathematical function).

The optical axis is an imaginary line passing through both the centers of the two opposite surfaces of the optical zone of a contact lens.

The line of sight (LOS), as known to a person skilled in the art is an imaginary line that connects the fixation point to the center of the entrance pupil and the center of the exit pupil to the fovea. LOS has been recommended by a task force sponsored by the Optical Society of American to be used as the reference axis for the measurement and reporting of the optical aberration of the eye (Applegate, et al., in Vision Science and Its Applications, OSA Technical Digest (Optical Society of America, Washington D.C.), 2000:146-149, herein incorporated by reference in its entirety). Usually, LOS is denoted by angle .kappa. measured from pupillary axis. The pupillary axis is an axis strikes the corner at right angles and passes through the center of the entrance pupil.

A “targeted spherical optical power” in reference to a contact lens means an optical power prescribed by an eye-care practitioner to provide a negative or positive spherical power correction. Traditionally, the targeted spherical optical power corresponds to the optical power at the center of the optical zone of a contact lens.

A “targeted cylindrical optical power” in reference to a contact lens means an optical power prescribed by an eye-care practitioner to correct astigmatism vision errors of a patient.

As used herein, “spherical aberration” in reference to a lens means that the optical power of the lens varies with the distance from the optical axis (radius or diameter), deviates from the ideal optical power (i.e., at the center of the optical zone). Negative spherical aberration is intended to describe that the optical power of a lens at a position deviate from the center of its optical zone is smaller (or more negative) than the optical power of the lens at the center of the optical zone. Positive spherical aberration is intended to describe that the optical power of a lens at a position deviate from the center of its optical zone is larger (or more positive) than the optical power of the lens at the center.

A “spherical aberration component” in reference to a toric contact lens is intended to describe that a component of the wavefront aberration of a toric lens can be defined by a spherical aberration-like Zernike term in Zernike polynomials.

Zernike polynomials are a set of functions that are orthogonal over the unit circle. They are useful for describing the shape of an aberrated wavefront. There exists several different normalization and numbering schemes for these polynomials. The Zernike polynomials are usually defined in polar coordinates (.rho.,.theta.), where .rho. is the radial coordinate ranging from 0 to 1 and .theta. is the azimuthal component ranging from 0 to 2.pi.. Each of the Zernike polynomials consists of three components: a normalization factor, a radial dependent component and an azimuthal dependent component. The radial component is a polynomial, whereas the azimuthal component is sinusoidal. A double indexing scheme is useful for unambiguously describing the functions, with the index n describing the highest power or order of the radial polynomial and the index m describing the azimuthal frequency of the azimuthal component.

Since Zernike polynomials are orthogonal, the aberrations are separable and can be treated as follows. The first order Zernike modes are the linear terms. The second order Zernike modes are the quadratic terms, correspond to power and astigmatism. The third order Zernike modes are the cubic terms, which correspond to the coma and trefoil. The fourth order Zernike modes spherical aberration, secondary astigmatism and quadrafoil. The fifth Zernike modes are the higher-order, irregular aberrations. Local irregularities in the wavefront within the pupil are represented by these higher-order Zernike.

A table of the proposed OSA Standard (Optical Society of America) Zernike Polynomials up to 6.sup.th order is displayed below (More information on Zernike polynomials is available on http://color.eri.harvard.edu/standardization/standards_TOPS4.pdf).

TABLE-US-00001 j n m Z.sub.n.sup.m (.rho., .theta.) 0 0 0 1 1 1 -1 2 .rho. sin .theta. 2 1 1 2 .rho. cos .theta. 3 2 -2 {square root over (6)} .rho..sup.2 sin 2.theta. 4 2 0 {square root over (3)} (2.rho..sup.2 – 1) 5 2 2 {square root over (6)} .rho..sup.2 cos 2.theta. 6 3 -3 {square root over (8)} .rho..sup.3 sin 3.theta. 7 3 -1 {square root over (8)} (3.rho..sup.3 – 2.rho.) sin .theta. 8 3 1 {square root over (8)} (3.rho..sup.3 – 2.rho.) cos .theta. 9 3 3 {square root over (8)} .rho..sup.3 cos 3.theta. 10 4 -4 {square root over (10)} .rho..sup.4 sin 4.theta. 11 4 -2 {square root over (10)} (4.rho..sup.4 – 3.rho..sup.2) sin 2.theta. 12 4 0 {square root over (5)} (6.rho..sup.4 – 6.rho..sup.2 + 1) 13 4 2 {square root over (10)} (4.rho..sup.4 – 3.rho..sup.2) cos 2.theta. 14 4 4 {square root over (10)} .rho..sup.4 cos 4.theta. 15 5 -5 {square root over (12)} .rho..sup.5 sin 5.theta. 16 5 -3 {square root over (12)} (5.rho..sup.5 – 4.rho..sup.3) sin 3.theta. 17 5 -1 {square root over (12)} (10.rho..sup.5 – 12.rho..sup.3 + 3.rho.) sin .theta. 18 5 1 {square root over (12)} (10.rho..sup.5 – 12.rho..sup.3 + 3.rho.) cos .theta. 19 5 3 {square root over (12)} (5.rho..sup.5 – 4.rho..sup.3) cos 3.theta. 20 5 5 {square root over (12)} .rho..sup.5 cos 5.theta. 21 6 -6 {square root over (14)} .rho..sup.6 sin 6.theta. 22 6 -4 {square root over (14)} (6.rho..sup.6 – 5.rho..sup.4) sin 4.theta. 23 6 -2 {square root over (14)} (15.rho..sup.6 – 20.rho..sup.4 + 6.rho..sup.2) sin 2.theta. 24 6 0 {square root over (7)} (20.rho..sup.6 – 30.rho..sup.4 + 12.rho..sup.2 – 1) 25 6 2 {square root over (14)} (15.rho..sup.6 – 20.rho..sup.4 + 6.rho..sup.2) cos 2.theta. 26 6 4 {square root over (14)} (6.rho..sup.6 – 5.rho..sup.4) cos 4.theta. 27 6 6 {square root over (14)} .rho..sup.6 cos 6.theta.

A “spherical aberration-like term” refers to any one of Z.sub.4.sup.0, Z.sub.6.sup.0, Z.sub.8.sup.0, Z.sub.10.sup.0 in the proposed OSA Standard (Optical Society of America) Zernike Polynomials or a combination of these Zernike terms.

Isolation of the spherical aberration component can be accomplished by measuring lenses, across the power range, on a lensometer system capable of decomposing the wavefront into a Zernike basis set. Examples of these devices are the Shack-Hartmann based system from Wavefront Sciences and the Lateral Shearing interferometric based system from Rotlex. These system can output the power profile of wavefront in a manner similar to an Ophthalmic wavefront sensor. A phoropter used to measure the subjective refraction of an eye averages the axi-symmetric terms, but can isolate the astigmatic component via the use of cylinderical lenses. Likewise, lensometers such as the Marco average the axi-symmetical terms of a wavefront, but can isolate the toric component.

A “power deviation” refers to a difference in powers between at a given lens position (.rho.,.theta.) and at the optical center (0,0) where the optical axis of the lens pass through, i.e., .DELTA.p=p.sub.x-p.sub.o, where .DELTA.p is power deviation at a lens position (.rho.,.theta.) relative to the optical center, p.sub..rho.,.theta. is the optical at the lens position (.rho.,.theta.), p.sub.0,0 is the optical power at the optical center.

A “substantially constant power profile” in reference to a contact lens is intended to describe a power profile in which optical power deviations at any positions (deviated from the center of the optical zone) within a 6 mm-diameter optical zone is between about -0.1 diopter to about 0.1 diopter.

“An optical model lens” refers to an ophthalmic lens that is designed in a computer system and generally does not contain other non-optical systems which are parts of a contact lens.

“A bevel” refers to a non-optical surface zone located at the edge of the posterior surface of a contact lens. Generally, the bevel is a significantly flatter curve and is usually blended with the base curve (optical posterior surface) of a contact lens and appears as an upward taper near the edge. This keeps the steeper base curve radius from gripping the eye and allows the edge to lift slightly. This edge lift is important for the proper flow of tears across the cornea and makes the lens fit more comfortable.

“A lenticular” refers to a non-optical surface zone of the anterior surface of a contact lens between the optical zone and the edge. The primary function of the lenticular is to control the thickness of the lens edge.

In one aspect, the invention provides a toric contact lens having a controlled optical power profile. A toric contact lens of the invention has an optical axis, an anterior surface having a first optical zone, and an opposite posterior surface having a second optical zone. The first optical zone and the second optical zone combine to provide a targeted cylindrical optical power and a targeted spherical optical power. At least one of the first and second optical zone has an aspherical surface which is designed to provide, in combination with the surface of the other optical zone, a controlled optical power profile which is substantially rotationally-symmetric with respect to the optical axis or incorporated a spherical aberration component, wherein the spherical aberration component is described by any one of fourth order, sixth order, eighth order Zernike spherical aberration-like terms and has a value of -0.5 diopter to about -1.5 diopters at a distance of 3 mm from the optical axis. In accordance with the invention, the term “substantially rotationally-symmetric” in reference to a toric contact lens is intended to describe that optical powers at a given radius from the optical axis within the optical zone of the lens are substantial constant, i.e., the maximum difference in optical power is less than about 0.05 diopters measured at 3 mm from the optical axis.

In accordance with the invention, one of the first optical zone or the second optical zone is a toroidal surface and the other zone is a spherical surface or preferably an aspheric surface.

The toroidal surface is formed by defining a curve in the Y-Z plane, wherein the Z-axis passes through the apex of the curve in normal direction, and then rotating this curve around an axis parallel to the Y-axis from a distance r. The value of the distance r is selected based on a desired cylindrical optical power of a contact lens for correcting a wearer’s astigmatism. The curve can be defined by any mathematic function, preferably by a conic function (Eq. 1) or a polynomial function (Eq. 2)

.times..times..times..times..alpha..times..alpha..times..alpha..times..alp- ha..times..alpha..times..alpha..times..alpha..times. ##EQU00001## in which c is the curvature (the reciprocal of the radius), k is a conic constant and .alpha..sub.1 to .alpha..sub.7 are the coefficients. The value of the distance r can be selected to impart a desired cylindrical optical power to the contact lens for correcting astigmatism errors of an eye.

The toroidal surface can also be a biconic surface defined by Eq. 3:

.times..times..times..times..times..times. ##EQU00002## where c.sub.x and c.sub.y are the curvatures at x and y meridians, k.sub.x and k.sub.y are conic constants, and Z-axis passes through the apex of the surface.

In accordance with the invention, the non-toroidal aspheric surface is preferably defined by rotating a curve of Eq. 1 or 2 around Z-axis.

In accordance with the invention, the optical axis of a contact lens can be the central axis which passes through the geometrical centers of the anterior and posterior surfaces.

In a preferred embodiment, the optical axis coincides substantially with the line-of-sight (LOS) of an eye. It is believed that with higher levels of aberrations, it becomes more critical to align the refractive correction over the eye’s line of sight, not the center of the lens.

In accordance with the invention, the line of sight of an eye can be measurement data of an eye of an individual or preferably characteristic data representing statistically the line of sight of eyes of individuals from a population.

Any suitable method can be used to obtain the line of sight of an eye. For example, one can obtain the LOS of an eye through wavefront data and corneal topography of the eye fixated in primary gaze.

Due to the decentration of the fovea (typically temporal and inferior) and the eye’s aberrations, the line of sight of the eye is not typically aligned to the geometric or mechanical axis of the eye. In such case, the contact lens will not provide optimal visual adjustment to the images conveyed to the eye of the wearer.

In a preferred embodiment, lens power deviation at a distance of 3 mm from the optical axis are from about -0.5 diopters to about -1.5 diopters, preferably from about -0.8 diopters to about -1.1 diopters. Lens power deviation at a position is intended to describe the difference in power between at the point where the optical axis passes through and at that position (P.sub.o-Pi).

In another preferred embodiment, the controlled optical power profile of the lens comprises a spherical aberration component which is described by any one of Z.sub.4.sup.0, Z.sub.6.sup.0, Z.sub.8.sup.0, Z.sub.10.sup.0 in the proposed OSA Standard (Optical Society of America) Zernike Polynomials or a combination of these Zernike terms, wherein the spherical aberration component has a value of -0.5 diopter to about -1.5 diopters, preferably from about -0.8 diopters to about -1.1 diopters, at a distance of 3 mm from the optical axis. Preferably, the spherical aberration component is described by Z.sub.4.sup.0. When just calculating the value of Z(4,0) term in RMS is from about -0.034 .mu.m (corresponding to a spherical aberration value of -0.2 D) to about -0.168 .mu.m (corresponding to a spherical aberration value of -1.0 D).

In another preferred embodiment, a toric contact lens of the invention is a toric multifocal contact lens. One of the first and second optical zones is a toroidal surface, the other optical zone comprises a central circular area having a diameter of from about 2.0 mm to about 3.50 mm and an annular region surrounding the central circular area. The central circular area and the annular region are concentric with the optical axis. The first and second optical zones combine together to provide a targeted cylindrical optical power to correct astigmatism vision errors and a multifocal spherical optical power to compensate for presbyopia.

The annular region surrounding the central circular area has a surface to provide a substantially constant power (base power or targeted power) from the inner peripheral edge to the outer peripheral edge for distance vision correction. The surface can be spherical or aspherical.

The central circular area is a progressive power addition zone for near vision correction and optionally for intermediate vision correction. It is substantially concentric with the optical axis. The progressive power addition zone preferably has a diameter of about 2.0 to about 3.5, more preferably about 2.2 mm to 3.0 mm.

Preferably, the first optical zone of the anterior surface is the toroidal surface or the biconic surface and the posterior surface comprises the progressive power addition zone.

The optical zone which is a toroidal or biconic surface can have a shape of any conventional toric lens. Preferably, it is circular. More preferably, it is substantially concentric with the optical axis.

It is understood that each lens in the series of contact lenses can have one or more non-optical zones which surround the optical zone. A person skill in the art will know well how to incorporate a family of common non-optical zones into a lens design.

A toric contact lens of the invention can further comprise one or more orientation features that provide a predetermined orientation on the eye. Exemplary orientation features include, but are not limited to, two thin zones, contour double slab-off, prism ballast carrier, and the like. Preferably, a toric contact lens of the invention has an orientation feature disclosed in U.S. Pat. No. 7,052,133.

The invention, in another aspect, provides a family of toric contact lenses having a series of different targeted cylindrical optical powers and a series of different targeted spherical optical powers, wherein each contact lens in the series has an optical axis, an anterior surface having a first optical zone, and an opposite posterior surface having a second optical zone, wherein one of the first and second optical zones is a toroidal surface whereas the other optical zone is a non-toroidal spherical or aspherical surface, wherein the surface of at least one of the first and second optical zone is designed to provide, in combination with the surface of the other optical zone, provide a controlled optical power profile in which (1) the optical power deviations of the lens are substantially constant; (2) power deviation at a distance of 3 mm from the optical axis are from about -0.5 diopter to about -1.5 diopters; (3) power deviation at a distance of 3 mm from the optical axis is from about 0.2 diopter to about 1.0 diopter smaller than power deviations at a distance of 2 mm from the optical axis; or (4) there is a spherical aberration component described by any one of fourth order, sixth order, eighth order Zernike spherical aberration-like terms, or combination thereof, wherein the spherical aberration component has a value of -0.5 diopter to about -1.5 diopters at a distance of 3 mm from the optical axis.

In accordance with the invention, a series of lenses refers to a family of lenses each having a targeted spherical optical power of from about -15 to about 10 diopters (D), preferably from about -10 diopters to 6 diopters and a targeted cylindrical optical power, e.g., magnitudes from about 0.75 diopters to about 4.0 diopters.

Various embodiments of toroidal surface, non-toroidal surface, orientation features, and optical axis described can be used incorporated in this aspect of the invention.

In a preferred embodiment, each lens in the series is substantially free of optical power deviations.

In another preferred embodiment, the optical power deviation profile of each lens in the series are substantially rotationally-symmetric. More preferably, each lens having a targeted spherical optical power of from 0 to about 15 diopters is substantially free of power deviation; each lens having a targeted spherical optical power of from about -1.0 diopter to about -6.0 diopters has a power deviation profile mimicking that of a spherical lens with identical targeted spherical optical power; and each lens having a targeted spherical optical power of from about -6.0 diopter to about -15.0 diopters has a controlled optical power profile in which power deviation at a distance of 3 mm from the optical axis is from about 0.2 diopters to about 1.0 diopter less than the power deviation at a distance of 2 mm from the optical axis.

In another preferred embodiment, all lenses in the series have a substantially identical spherical aberration component which has a spherical aberration value of -0.5 diopter to about -1.5 diopters, preferably from about -0.8 diopters to about -1.1 diopters, at a distance of 3 mm from the optical axis.

In another preferred embodiment, all lenses in the series have a substantially identical spherical aberration component in which spherical aberration value at a distance of 3 mm from the optical axis is from about 0.2 diopters to about 1.0 diopter smaller than that at a distance of 2 mm from the optical axis.

In another preferred embodiment, the non-toroidal surface comprises a central circular area having a diameter of from about 1.0 mm to about 4.0 mm and an annular region surrounding the central circular area. The central circular area and the annular region are concentric with the optical axis. The non-toroidal surface and the toroidal surface combine together to provide a targeted cylindrical optical power to correct astigmatism vision errors and a multifocal spherical power to compensate for presbyopia.

The annular region surrounding the central circular area has a surface to provide a substantially constant power (base power or targeted power) from the inner peripheral edge to the outer peripheral edge for distance vision correction. The surface can be spherical or aspherical.

The central circular area is a progressive power addition zone for near vision correction and optionally for intermediate vision correction. It is substantially concentric with the optical axis. The progressive power addition zone preferably has a diameter of about 2.0 to about 3.5, more preferably about 2.2 mm to 3.0 mm.

The above-described various embodiments of the progressive power addition zone can be incorporated in this preferred embodiment.

It is understood that each lens in the series of contact lenses can have one or more non-optical zones which surround the optical zone. A person skill in the art will know well how to incorporate a family of common non-optical zones into a lens design.

By using an optical computer aided design (CAD) system and a mechanical CAD system, one can design a toric contact lens of the invention. An optical CAD system is used to design an optical model lens. Any known, suitable optical computer aided design (CAD) system may be used to design an optical model lens. Exemplary optical computer aided design systems includes, but are not limited to Advanced System Analysis program (ASAP) from Breault Research Organization and ZEMAX (Focus Software, Inc.). Preferably, the optical design will be performed using Advanced System Analysis program (ASAP) from Breault Research Organization with input from ZEMAX (Focus Software, Inc.).

The design of the optical model lens can be transformed by, for example, a mechanical CAD system, into a mechanical lens design that includes optical zones, non-optical zones and non-optical features. Exemplary non-optical zones and features of a contact lens include, but are not limited to bevel, lenticular, edge that joins the anterior and posterior surfaces of a contact lens, orientation features, and the like. Exemplary orientation features include, but are not limited to, a prism ballast or the like that uses a varying thickness profile to control the lens orientation, a faceted surface (e.g., ridge-off zone) in which parts of the lens geometry is removed to control the lens orientation, a ridge feature which orients the lens by interacting with the eyelid. Preferably, when transforming the design of an optimized optical model lens into a mechanical lens design, some common features of a family of contact lenses can be incorporated.

Any know, suitable mechanical CAD system can be used in the invention. Preferably, a mechanical CAD system capable of representing precisely and mathematically high order surfaces is used to design a contact lens. An example of such mechanical CAD system is Pro/Engineer.

Preferably, the design of a contact lens may be translated back and forth between the optical CAD and mechanical CAD systems using a translation format which allows a receiving system, either optical CAD or mechanical CAD, to construct NURBs or Beizier surfaces of an intended design. Exemplary translation formats include, but are not limited to, VDA (verband der automobilindustrie) and IGES (Initial Graphics Exchange Specification). By using such translation formats, overall surface of lenses can be in a continuous form that facilitates the production of lenses having radially asymmetrical shapes. Beizier and NURBs surface are particular advantageous for presbyopic design because multiple zones can be blended, analyzed and optimized.

Any mathematical function can be used to describe the anterior surface, posterior surface, peripheral edge of an ophthalmic lens, as long as they have sufficient dynamic range which allow the design of that lens to be optimized. Exemplary mathematical functions include conic and quadric functions, polynomials of any degree, Zernike polynomials, exponential functions, trigonometric functions, hyperbolic functions, rational functions, Fourier series, and wavelets. Preferably, a combination of two or more mathematical functions are used to describe the front (anterior) surface and base (posterior) surface of an ophthalmic lens. More preferably, Zernike polynomials are used to describe the front (anterior) surface and base (posterior) surface of an ophthalmic lens. Even more preferably, Zernike polynomials and spline-based mathematical functions are used together to describe the front (anterior) surface and base (posterior) surface of an ophthalmic lens.

Toric contact lenses of the invention can be either hard or soft lenses. Soft contact lenses of the invention is preferably made from a soft contact lens material, such as hydrogels. Any known suitable hydrogels can be used in the invention. Preferably, a silicone-containing hydrogel is used in the invention. It will be understood that any lens described above comprising any soft contact lens material would fall within the scope of the invention.

After completing a desired design, a toric contact lens can be produced in a computer-controlled manufacturing system. The lens design can be converted into a data file containing control signals that is interpretably by a computer-controlled manufacturing device. A computer-controlled manufacturing device is a device that can be controlled by a computer system and that is capable of producing directly an ophthalmic lens or an optical tools for producing an ophthalmic lens. Any known, suitable computer controllable manufacturing device can be used in the invention. Preferably, a computer controllable manufacturing device is a numerically controlled lathe, preferably a two-axis lathe with a 45.degree. piezo cutter or a lathe apparatus disclosed by Durazo and Morgan in U.S. Pat. No. 6,122,999, herein incorporated by reference in its entirety, more preferably a numerically controlled lathe from Precitech, Inc., for example, such as Optoform ultra-precision lathes (models 30, 40, 50 and 80) having Variform piezo-ceramic fast tool servo attachment.

Preferred methods for designing and manufacturing toric contact lenses of the invention are those described in co-pending U.S. Patent Application Publication No. US 2006/0055876 A1, herein incorporated by reference in its entirety.

Toric contact lenses of the invention can now be manufactured each of which has a targeted cylindrical optical power to correct astigmatism vision errors and a targeted spherical optical power to compensate for myopia, hypermetropia, or presbyopia. Toric contact lenses of the invention may be produced by any convenient means, for example, such as lathing and molding. Preferably, toric contact lenses are molded from contact lens molds including molding surfaces that replicate the contact lens surfaces when a lens is cast in the molds. For example, an optical cutting tool with a numerically controlled lathe may be used to form metallic optical tools. The tools are then used to make convex and concave surface molds that are then used, in conjunction with each other, to form the lens of the invention using a suitable liquid lens-forming material placed between the molds followed by compression and curing of the lens-forming material.

Accordingly, contact lenses according to the invention can be manufactured by imparting contact lens molds two molding surfaces, a first molding surface and a second molding surface. The molds having the first molding surface or the second molding surface, in conjunction with each other, form a toric contact lens of the invention.

In a further aspect, the present invention provides a method for producing a toric contact lens having a controlled optical profile. The method comprises the steps of shaping a contact lens by a manufacturing means to have an optical axis, an anterior surface having a first optical zone, and an opposite posterior surface having a second optical zone, wherein the first optical zone and the second optical zone combine to provide a targeted cylindrical optical power and a targeted spherical optical power, wherein at least one of the first and second optical zone has an aspherical surface which is designed to provide, in combination with the surface of the other optical zone, a controlled optical power profile which is substantially rotationally-symmetric with respect to the optical axis or incorporated a spherical aberration component, wherein the spherical aberration component is described by any one of fourth order, sixth order, eighth order Zernike spherical aberration-like terms and has a value of -0.5 diopter to about -1.5 diopters at a distance of 3 mm from the optical axis.

In still a further aspect, the present invention provides a method for producing a series of toric contact lenses having a series of different targeted cylindrical optical powers and a series of different targeted spherical optical powers. The method comprises the steps of shaping each toric contact lens by a manufacturing means to have an optical axis, an anterior surface having a first optical zone, and an opposite posterior surface having a second optical zone, an optical axis, an anterior surface having a first optical zone, and an opposite posterior surface having a second optical zone, wherein one of the first and second optical zones is a toroidal surface whereas the other optical zone is a non-toroidal spherical or aspherical surface, wherein the surface of at least one of the first and second optical zone is designed to provide, in combination with the surface of the other optical zone, provide a controlled optical power profile in which (1) the optical power deviations of the lens are substantially constant; (2) power deviation at a distance of 3 mm from the optical axis are from about -0.5 diopter to about -1.5 diopters; (3) power deviation at a distance of 3 mm from the optical axis is from about 0.2 diopter to about 1.0 diopter smaller than power deviations at a distance of 2 mm from the optical axis; or (4) there is a spherical aberration component described by any one of fourth order, sixth order, eighth order Zernike spherical aberration-like terms, or combination thereof, wherein the spherical aberration component has a value of -0.5 diopter to about -1.5 diopters at a distance of 3 mm from the optical axis.

Preferably, a toric contact lens of the invention is fabricated by using a numerically controlled lathe, for example, such as Optoform ultra-precision lathes (models 30, 40, 50 and 80) having Variform piezo-ceramic fast tool servo attachment from Precitech, Inc.

The invention has been described in detail, with particular reference to certain preferred embodiments, in order to enable the reader to practice the invention without undue experimentation. A person having ordinary skill in the art will readily recognize that many of the previous components, compositions, and/or parameters may be varied or modified to a reasonable extent without departing from the scope and spirit of the invention. Furthermore, titles, headings, example materials or the like are provided to enhance the reader’s comprehension of this document, and should not be read as limiting the scope of the present invention. Accordingly, the invention is defined by the following claims, and reasonable extensions and equivalents thereof.

1. A method for significantly reducing SEALs in a silicone hydrogel lens, comprising the step of providing a contact lens comprising a center stiffness of about 1 psi.mm.sup.2 or less, wherein the lens exhibits an advancing dynamic contact angle of less than about 55 degrees.

2. The method of claim 1, wherein the lens provided comprises a center stiffness less than about 0.5 psi.

3. The method of claim 1 wherein said lens is a reaction product of at least one silicone macromer and at least one hydrophilic monomer.

4. The method of claim 3 wherein said at least one silicone containing macromer comprises at least one polydimethylsiloxane methacrylated with pendant hydrophilic groups.

5. The method of claim 3 wherein said at least one silicone containing macromer comprises at least one oxyperm component.

6. The method of claim 3, 4 or 5 wherein said hydrophilic monomer is selected from the group consisting of 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, N,N-dimethylacrylamide, N-vinylpyrrolidone, 2-vinyl-4,4′-diethyl-2-oxazolin-5-one, methacrylic acid and 2-hydroxyethyl methacrylamide.

7. The method of claim 1, wherein said lens further comprises an internal wetting agent selected from the group consisting of polyamides, polylactams, polyimides, polylactones, and combinations thereof

8. The method of claim 1, wherein said lens further the reaction product of a silicone based macromer and a polymerizable mixture comprising Si.sub.8-10 monomethacryloxy terminated polydimethyl siloxane, polydimethylsiloxane other than Si.sub.8-10 monomethacryloxy terminated polydimethyl siloxane, and a hydrophilic monomer.

9. The method of claim 1, wherein said lens further comprises the reaction product of a silicone based macromer Group Transfer Polymerization product and a polymerizable mixture comprising Si.sub.8-10 monomethacryloxy terminated polydimethyl siloxane, polydimethylsiloxane other than Si.sub.8-10 monomethacryloxy terminated polydimethyl siloxane, and a hydrophilic monomer.

10. The method of claim 1, wherein the polymerizable mixture comprises Si.sub.8-10 monomethacryloxy terminated polydimethyl siloxane; methacryloxypropyl tris(trimethyl siloxy) silane; N,N-dimethylacrylamide; 2-hydroxy ethyl methacrylate; and tetraethyleneglycol dimethacrylate.

11. The method of claim 9, wherein the polymerizable mixture comprises Siy9 monomethacryloxy terminated polydimethyl siloxane; methacryloxypropyl tris(trimethylsiloxy) silane; N,N-dimethylacrylamide; 2-hydroxyethyl methacrylate; and tetraethyleneglycol dimethacrylate.

12. The method of claim 10, wherein the macromer is present in an amount of about 10 to about 60 wt percent, the Si.sub.8-10 monomethacryloxy terminated polydimethyl siloxane is present in an amount of about 0 to about 45 wt percent; the methacryloxypropyl tris(trimethylsiloxy) silane is present in an amount of about 0 to about 40 wt percent; the N,N-dimethylacrylamide is present in an amount of about 5 to about 40 wt percent; the 2-hydroxyethyl methacrylate is present in an amount of about 0 to about 10 wt percent; and the tetraethyleneglycol dimethacrylate is present in an amount of about 0 to about 5 wt percent.

13. The method of claim 10, wherein the polymerizable mixture further comprises poly(N-vinyl pyrrolidinone).

14. The method of claim 1, wherein the polymerizable mixture further comprises poly(N-vinyl pyrrolidinone).

15. The method of claim 12, wherein the polymerizable mixture further comprises about 0 to about 10 wt percent poly(N-vinyl pyrrolidinone).

16. The method of claim 1, further comprising a coating selected from the group consisting of poly(acrylic acid), poly(methacrylic acid), poly(maleic acid), poly(itaconic acid), poly(acrylamide), poly(dimethacrylamide), block or random copolymers of (meth)acrylic acid, acrylic acid, maleic acid, itaconic acid with any reactive vinyl monomer, carboxymethylated polymers, such as carboxymethylcellulose, dextran, polyvinyl alcohol, polyethylene oxide, poly(2-hydroxy ethyl methacrylate), polysulfonates, polysulfates, polylactam, polyglycolic acid, polyamines, and mixtures thereof.

17. The method of claim 1, further comprising a coating selected from the group consisting of poly(acrylic acid), poly(methacrylic acid), poly(maleic acid), poly(itaconic acid), poly(acrylamide), poly(dimethacrylamide), block or random copolymers of (meth)acrylic acid, acrylic acid, maleic acid, itaconic acid with any reactive vinyl monomer, carboxymethylated polymers, such as carboxymethylcellulose, dextran, polyvinyl alcohol, polyethylene oxide, poly(2-hydroxyethyle methacrylate), polysulfonates, polysulfates, polylactam, polyglycolic acid, polyamines, and mixtures thereof.

18. The method of claim 17, wherein the coating is poly(acrylic acid), poly(acrylamide), or poly(2-hydroxyethyl methacrylate).

19. The method of claim 1, wherein said lens is formed from a polymer reaction mixture comprising less than about 21 weight %3-methacryloxypropyltris(trimethylsiloxy) silane.

20. The method of claim 1 wherein said lens is formed from a polymer reaction mixture comprising at least one linear, branched or star macromer.

21. The method of claims 1, 19, or 20 wherein said lens is formed via direct molding.

22. The method of claim 21 wherein said lens is treated with water, a solvent or both after direct molding.

23. The method of claim 1, 19 or 20 wherein said reaction mixture further comprises at least one diluent.

24. The method of any of claims 1, 19 or 20 wherein said lens is plasma coated
Contact Lens Description
FIELD OF THE INVENTION

The present invention relates to contact lenses. In particular, the invention provides silicone hydrogel contact lenses that exhibit reduced back surface debris and a reduced incidence of superior epithelial arcurate lesions.

BACKGROUND OF THE INVENTION

The use of contact lenses for reasons of cosmetics and for the correction of visual acuity is well known. However, use of contact lenses is known to result in the development of either or both superior epithelial arcuate lesions and superior arcuate staining. Additionally, debris such as mucin balls, cellular debris, lint, dust, bubbles, make-up, or the like (“back-trapped debris”) may become trapped between the back surface of the lens and the eye. These problems have been found across the range of conventional soft contact lenses, but are found to be substantially more prevalent in the high oxygen permeability silicone hydrogel contact lenses introduced into the market within the last several years. Thus, a need exists for a lens that eliminates or reduces superior arcuate lesions and staining as well as back-trapped debris.

DESCRIPTION OF THE INVENTION AND ITS PREFERRED EMBODIMENTS

The present invention provides silicone hydrogel contact lenses in which the formation of superior arcuate staining of grade 2 or higher and superior epithelial arcuate lesions along with back-trapped debris is significantly reduced or substantially eliminated. It is a discovery of the invention that by controlling stiffness of the lens at the lens’ center, lesion formation and staining may be reduced or eliminated. Additionally, by controlling the lenticular junction stiffness and surface wettability, back-trapped debris also may be significantly reduced or eliminated.

In one embodiment, the invention provides a contact lens comprising, consisting essentially of, and consisting of a center stiffness of about 1 psimm.sup.2 or less and a lenticular junction stiffness of about 4.4 psimm.sup.2 or less, wherein the lens exhibits an advancing contact angle of less than about 120 degrees. For purposes of the invention, the measurements necessary for calculating stiffness are taken at room temperature and the advancing contact angle is measured using physiologically buffered saline. By “center” is meant the center of the optic zone. By “lenticular junction” is meant the junction of the lenticular zone with the bevel or, for those lenses without a bevel, a point about 1.2 mm from the lens edge.

The stiffness of a lens at any point may be determined by multiplying the lens’ Young’s modulus with the square of the thickness of the lens at that point. The center stiffness of a lens, thus, may be calculated by determining the thickness of the lens at the center of the lens’ optic zone and multiplying the square of that value by the lens’ modulus. The lenticular junction stiffness may be calculated in the same manner.

It is a discovery of the invention that by maintaining the center and lenticular junction stiffnesses and the advancing contact angle of a lens at certain levels, the incidence of SEALs, meaning superior arcuate lesions and superior arcuate staining of about grade 2 or higher, and back-trapped debris may be significantly reduced or substantially eliminated. By “grade 2″ staining is meant that small aggregates, or groupings, of corneal epithelial cell loss are visible using sodium fluorescein. By “significantly reduced” means that SEALs are reduced to an incidence of about 1 percent or less and that less than about 35 percent of lens wearers experience no back-trapped debris or only a mild amount, meaning an easily visible amount on slit lamp examination at a magnification of about 16 to about 20.times., but which amount is not clinically significant.

Preferably, the center stiffness of lenses of the invention is less than about 1 psimm.sup.2, the lenticular junction stiffness is less than about 4 psimm.sup.2, and the lens has an advancing contact angle less than about 120 degrees. More preferably, the center stiffness of lenses of the invention is less than about 1 psimm.sup.2 the lenticular junction stiffness is less than about 4 psimm.sup.2, and the lens has an advancing contact angle less than about 80 degrees. Most preferably, the center stiffness of lenses of the invention is less than about 0.5 psimm.sup.2, the lenticular junction stiffness is less than about 4 psimm.sup.2 and the advancing contact angle is less than about 55 degrees.

The desired stiffnesses for the lenses of the invention may be obtained by combining materials of any suitable Young’s modulus with a suitable lens thickness to obtain the desired stiffness. Additionally, the material from which the lens is formed may be such that the lens surface exhibits the desired wettability, as exhibited by advancing contact angle. Alternatively, the lens may be coated with a material that exhibits the desired wettability.

One ordinarily skilled in the art will be capable of determining the modulus and thickness combinations that may be used to obtain the desired stiffnesses for the lenses of the invention. The lenses of the invention are soft contact lenses made of silicone hydrogel. Silicone hydrogels useful for forming the lenses of the invention may be made by reacting blends of macromers, monomers, and combinations thereof along with additives such as ultraviolet blockers, tints, and polymerization initiators. Suitable silicone hydrogel materials include, without limitation, silicone hydrogels made from silicone macromers and hydrophilic monomers. Examples of such silicone macromers include, without limitation, polydimethylsiloxane methacrylated with pendant hydrophilic groups as described in U.S. Pat. Nos. 4,259,467; 4,260,725 and 4,261,875; polydimethylsiloxane macromers with polymerizable function described in U.S. Pat. Nos. 4,136,250; 4,153,641; 4,189,546; 4,182,822; 4,343,927; 4,254,248; 4,355,147; 4,276,402; 4,327,203; 4,341,889; 4,486,577; 4,605,712; 4,543,398; 4,661,575; 4,703,097; 4,837,289; 4,954,586; 4,954,587; 5,346,946; 5,358,995; 5,387,632; 5,451,617; 5,486,579; 5,962,548; 5,981,615; 5,981,675; and 6,039,913; and combinations thereof. They may also be made using polysiloxane macromers incorporating hydrophilic monomers such as those described in U.S. Pat. Nos. 5,010,141; 5,057,578; 5,314,960; 5,371,147 and 5,336,797; or macromers comprising polydimethylsiloxane blocks and polyether blocks such as those described in U.S. Pat. Nos. 4,871,785 and 5,034,461. All of the cited patents are hereby incorporated in their entireties by reference.

Suitable materials also may be made from combinations of oxyperm and ionoperm components such as is described in U.S. Pat. Nos. 5,760,100; 5,776,999; 5,789,461; 5,807,944; 5,965,631 and 5,958,440. Hydrophilic monomers may be incorporated into such copolymers, including 2-hydroxyethyl methacrylate (“HEMA”), 2-hydroxyethyl acrylate, N,N-dimethylacrylamide (“DMA”), N-vinylpyrrolidone, 2-vinyl-4,4′-dimethyl-2-oxazolin-5-one, methacrylic acid, and 2-hydroxyethyl methacrylamide. Additional siloxane monomers may be incorporated such as tris(trimethylsiloxy)silylpropyl methacrylate, or the siloxane monomers described in U.S. Pat. Nos. 5,998,498; 3,808,178; 4,139,513; 5,070,215; 5,710,302; 5,714,557 and 5,908,906. They may also include various toughening agents, tints, UV blockers, and wetting agents. They can be made using diluents such as primary alcohols, or the secondary or tertiary alcohols described in U.S. Pat. No. 6,020,445. All of the cited patents are hereby incorporated in their entireties by reference.

In a preferred embodiment, the lenses of the invention are made by reacting a macromer with a reaction mixture that includes silicone based monomers and hydrophilic monomers. The macromers may be made by combining a methacrylate or an acrylate and a silicone in the presence of a Group Transfer Polymerization (“GTP”) catalyst. These macromers typically are copolymers of various monomers. They may be formed in such a way that the monomers come together in distinct blocks, or in a generally random distribution. These macromers may furthermore be linear, branched, or star shaped. Branched structures are formed for instance if polymethacrylates, or crosslinkable monomers such as 3-(trimethylsiloxy)propyl methacrylate are included in the macromer.

Initiators, reaction conditions, monomers, and catalysts that can be used to make GTP polymers are described in “Group-Transfer Polymerization” by O. W. Webster, in Encyclopedia of Polymer Science and Engineering Ed. (John Wiley & Sons) p. 580, 1987. These polymerizations are conducted under anhydrous conditions. Hydroxyl-functional monomers, like HEMA, may be incorporated as their trimethylsiloxy esters, with hydrolysis to form free hydroxyl groups after polymerization. GTP offers the ability to assemble macromers with control over molecular weight distribution and monomer distribution on the chains. This macromer may then be reacted with a reaction mixture of predominantly polydimethylsiloxane (preferably, monomethacryloxypropyl terminated polydimethylsiloxane (“mPDMS”), and hydrophilic monomers. Preferred mPDMS is of the formula:

##STR00001## wherein b=0 to 100, preferably 8 to 10; R.sub.58 is a monovalent group containing a ethylenically unsaturated moiety, preferably a monovalent group containing a styryl, vinyl, or methacrylate moiety, more preferably a methacrylate moiety; each R.sub.59 is independently a monovalent alkyl, or aryl group, which may be further substituted with alcohol, amine, ketone, carboxylic acid or ether groups, preferably unsubstituted monovalent alkyl or aryl groups, more preferably methyl; and R.sub.60 is a monovalent alkyl, or aryl group, which may be further substituted with alcohol, amine, ketone, carboxylic acid or ether groups, preferably unsubstituted monovalent alkyl or aryl groups, preferably a C.sub.1-10 aliphatic or aromatic group which may include hetero atoms, more preferably C.sub.3-8 alkyl groups, most preferably butyl, particularly sec-butyl group.

Preferred macromer components include mPDMS, 3-methacryloxypropyltris(trimethylsiloxy)silane (“TRIS”), methyl methacrylate, HEMA, DMA, methacrylonitrile, ethyl methacrylate, butyl methacrylate, 2-hydroxypropyl-1-methacrylate, 2-hydroxyethyl methacrylamide and methacrylic acid. It is even more preferred that the macromer is made from a reaction mixture of HEMA, methyl methacrylate, TRIS, and mPDMS. It is most preferred that macromer is made from a reaction mixture comprising, consisting essentially of, or consisting of about 19.1 moles of HEMA, about 2.8 moles of methyl methacrylate, about 7.9 moles of TRIS, and about 3.3 moles of mono-methacryloxypropyl terminated mono-butyl terminated polydimethylsiloxane, and is completed by reacting the aforementioned material with about 2.0 moles per mole of 3-isopropenyl-.omega.,.omega.-dimethylbenzyl isocyanate using dibutyltin dilaurate as a catalyst.

The reactive components of silicone hydrogels typically are a combination of hydrophobic silicone with very hydrophilic components and these components are often immiscible due to their differences in polarity. Thus, it is particularly advantageous to incorporate a combination of hydrophobic silicone monomers with hydrophilic monomers, especially those with hydroxyl groups, into the macromer. The macromer can then serve to compatibilize the additional silicone and hydrophilic monomers that are incorporated in the final reaction mixture. These blends typically also contain diluents to further compatibilize and solubilize all components. Preferably, the silicone based hydrogels are made by reacting the following monomer mix: macromer; an Si.sub.8-10 monomethacryloxy terminated polydimethyl siloxane; and hydrophilic monomers together with minor amounts of additives and photoinitiators. It is more preferred that the hydrogels are made by reacting macromer; an Si.sub.8-10 monomethacryloxy terminated polydimethyl siloxane; TRIS; DMA; HEMA; and tetraethyleneglycol dimethacrylate (“TEGDMA”). It is most preferred that the hydrogels are made from the reaction of (all amounts are calculated as weight percent of the total weight of the combination) macromer (about 18%); an Si.sub.8-10 monomethacryloxy terminated polydimethyl siloxane (about 28%); TRIS (about 14%); DMA (about 26%); HEMA (about 5%); TEGDMA (about 1%), polyvinylpyrrolidone (“PVP”) (about 5%); with the balance comprising minor amounts of additives and photoinitiators, and that the reaction is conducted in the presence of 20% wt dimethyl-3-octanol diluent.

The desired wettability and, thus, the desired advancing contact angle, for the lenses’ surfaces may be obtained by any convenient method such as by application of a suitable hydrophilic coating. The coatings may be applied by any convenient method. Preferred hydrophilic coatings include, without limitation, poly(acrylic acid), poly(methacrylic acid), poly(maleic acid), poly(itaconic acid), poly(acrylamide), poly(dimethacrylamide), block or random copolymers of (meth)acrylic acid, acrylic acid, maleic acid, itaconic acid with any reactive vinyl monomer, carboxymethylated polymers, such as carboxymethylcellulose, dextran, polyvinyl alcohol, polyethylene oxide, poly(HEMA), polysulfonates, polysulfates, polylactam, polyglycolic acid, polyamines, and the like, and mixtures thereof. More preferably, the coating is poly(acrylic acid), poly(methacrylic acid), poly(dimeth)acrylamide, poly(acrylamide), or poly(HEMA). Most preferably, poly(acrylic acid), poly(acrylamide), or poly(HEMA) is used.

In a preferred coating method, the lens surface to be coated is contacted with the hydrophilic coating and at least one coupling agent in any convenient manner. Useful coupling agents include, without limitation, dehydrating agents such as carbodiimides, acid halides of inorganic or organic acids, isocyanides, and the like, and combinations thereof. Examples of suitable coupling agents include, without limitation, carbodiimides, N,N’-carbonyldiimidazole, phosphoryl chloride, titanium tetrachloride, sulfuryl chloride fluoride, chlorosulfonyl isocyanate, phosphorus iodide, pyridinium salts of tributyl amine, phenyl dichlorophosphate, polyphosphate ester, chlorosilanes, and the like as well as mixtures of tributyl phosphorus and phenyl isocyanate, alkyl chloroformates and triethyl amine, 2-chloro-1,3,5-trinitrobenzene and pyridine, methyl sulfuryl chloride and diethyl amine, and triphenylphosphine, carbon tetrachloride and triethyl amine. Preferred coupling agents are carbodiimides. More preferred are 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and dicyclohexyl carbodiimide.

The lens may be placed in a solution of coating and solvent into which the coupling agent is added. As an alternative, and preferably, the lens surface may first be contacted with one of the coupling agent or coating and then contacted with the other. Most preferably, the surface is first contacted by any convenient method with the coupling agent for a period of about 0.5 to about 60 minutes, preferably for about 1 to about 30 minutes. Subsequently, the surface is contacted with the hydrophilic polymer solution for a period of about 1 to about 1000 minutes, preferably about 5 to about 200 minutes. Suitable solvents for use are those that are capable of solubilizing both the hydrophilic polymer and the coupling agent. Preferably, the coating process is carried out in a water or aqueous solution, which solution preferably contains buffers and salts. The carbodiimide 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (“EDC”) is effective in aqueous solutions and, thus, is a most preferred coupling agent.

A coupling effective amount of the coupling agent is used which amount is sufficient to couple the hydrophilic coating to the lens surface. The precise amount of coupling agent used will depend on the lens surface chemistry as well as the coating and coupling agent selected. Generally, about 0.01 to about 10 weight percent, preferably about 0.01 to about 5.0, more preferably, about 0.01 to about 1 weight percent of the coating solution is used. By coating solution is meant the coating with one or more of the solvent, coupling agent, and, optionally, a buffer. Typically, the amount of coating solution used per lens will be about 0.1 to about 100 g, preferably about 0.5 to about 50 grams, more preferably about 1 to about 10 g per lens. A coating effective amount of the hydrophilic coating is used meaning an amount sufficient to coat the surface to the desired degree. Generally, the amount of polymer used is about 0.001 to about 100, preferably about 0.01 to about 50, more preferably, about 0.01 to about 10 weight percent of the coating solution.

Following contacting, the surface may be washed with water or buffered saline solution to remove unreacted polymer, coupling agent, solvent, and byproducts. Optionally, the coated surface may be heated in water to extract residual coating, coupling agent, and byproducts and to ensure the break down of any coupling agent–stabilizer complexes that may have formed.

Alternatively, the desired wettability may be obtained using an internal wetting agent in the lens formulation, which wetting agent is non-fugitive by means of entanglement or copolymerization into the crosslinked lens polymer network and has a weight average molecular weight of about 100,000 to 500,000 daltons, preferably about 300,000 to about 500,000 daltons. Suitable wetting agents include, without limitation, polyamides, polylactams, polyimides, polylactones, and combinations thereof. Preferable wetting agents are PVP, polyacrylamide, polydimethacrylamide, polyoxazolone, imidazolones, hydrolyzed and non-hydrolized polyvinylacetate, and combinations thereof. More preferably, PVP is used.

The lenses of the invention may be made using any known process for contact lens production. Preferably, the lenses are made by photocuring the lens composition and, if desired, applying a coating to the cured lens. Various processes are known for molding the reaction mixture in the production of contact lenses, including spincasting and static casting. The preferred method for producing contact lenses of this invention is by the direct molding of the silicone hydrogels, which is economical, and enables precise control over the final shape of the hydrated lens. For this method, the reaction mixture is placed in a mold having the shape of the final desired silicone hydrogel, i.e. water-swollen polymer, and the reaction mixture is subjected to conditions whereby the monomers polymerize, to thereby produce a polymer in the approximate shape of the final desired product. The conditions for such polymerization are well known in the art. The polymer mixture optionally may be treated with a solvent and then water, producing a silicone hydrogel having a final size and shape similar to the size and shape of the original molded polymer article. This method can be used to form contact lenses and is further described in U.S. Pat. Nos. 4,495,313, 4,680,336, 4,889,664 and 5,039,459 incorporated herein by reference in their entireties.

The invention will be clarified by consideration of the following, non-limiting examples.

EXAMPLES

Macromer Preparation

To a dry container housed in a dry box under nitrogen at ambient temperature was added 30.0 g (0.277 mol) of bis(dimethylamino)methylsilane, a solution of 13.75 ml of a 1M solution of tetrabutyl ammonium-m-chlorobenzoate (“TBACB”) (386.0 g TBACB in 1000 ml dry THF), 61.39 g (0.578 mol) of p-xylene, 154.28 g (1.541 mol) methyl methacrylate (1.4 equivalents relative to initiator), 1892.13 (9.352 mol) 2-(trimethylsiloxy)ethyl methacrylate (8.5 equivalents relative to initiator) and 4399.78 g (61.01 mol) of THF. To a dry, three-necked, round-bottomed flask equipped with a thermocouple and condenser, all connected to a nitrogen source, was charged the above mixture prepared in the dry box.

The reaction mixture was cooled to 15.degree. C. while stirring and purging with nitrogen. After the solution reaches 15.degree. C., 191.75 g (1.100 mol) of 1-trimethylsiloxy-1-methoxy-2-methylpropene (1 equivalent) was injected into the reaction vessel. The reaction was allowed to exotherm to approximately 62.degree. C. and then 30 ml of a 0.40 M solution of 154.4 g TBACB in 11 ml of dry THF was metered in throughout the remainder of the reaction. After the temperature of reaction reached 30.degree. C. and the metering began, a solution of 467.56 g (2.311 mol) 2-(trimethylsiloxy)ethyl methacrylate (2.1 equivalents relative to the initiator), 3636.6 g (3.463 mol) n-butyl monomethacryloxypropyl-polydimethylsiloxane (3.2 equivalents relative to the initiator), 3673.84 g (8.689 mol) TRIS (7.9 equivalents relative to the initiator) and 20.0 g bis(dimethylamino)methylsilane was added.

The mixture was allowed to exotherm to approximately 38-42.degree. C. and then allowed to cool to 30.degree. C. At that time, a solution of 10.0 g (0.076 mol) bis(dimethylamino)methylsilane, 154.26 g (1.541 mol) methyl methacrylate (1.4 equivalents relative to the initiator) and 1892.13 g (9.352 mol) 2-trimethylsiloxy)ethyl methacrylate (8.5 equivalents relative to the initiator) was added and the mixture again allowed to exotherm to approximately 40.degree. C. The reaction temperature dropped to approximately 30.degree. C. and 2 gallons of tetrahydrofuran (“THF”) were added to decrease the viscosity. A solution of 439.69 g water, 740.6 g methanol and 8.8 g (0.068 mol) dichloroacetic acid was added and the mixture refluxed for 4.5 hours to de-block the protecting groups on the HEMA. Volatiles were then removed and toluene added to aid in removal of the water until a vapor temperature of 110.degree. C. was reached.

The reaction flask was maintained at approximately 110.degree. C. and a solution of 443 g (2.201 mol) dimethyl meta-isopropenyl benzyl isocyanate (“TMI”) and 5.7 g (0.010 mol) dibutyltin dilaurate were added. The mixture was reacted until the isocyanate peak was gone by IR. The toluene was evaporated under reduced pressure to yield an off-white, anhydrous, waxy reactive monomer. The macromer was placed into acetone at a weight basis of approximately 2:1 acetone to macromer. After 24 hrs, water was added to precipitate out the macromer and the macromer was filtered and dried using a vacuum oven between 45 and 60.degree. C. for 20-30 hrs.

Lens Formation

For Lenses 1 through 4, 7 and 10 through 13 of the Table, silicone hydrogels lenses were made using the above-described macromer and monomer mixtures specified in the Table according to the following procedure. All amounts are calculated as weight percent of the total weight of the combination with the balance of the mixture being minor amounts of additives. Contact lenses were formed by adding about 0.10 g of the monomer mix to the cavity of an eight cavity lens mold of the type described in U.S. Pat. No. 4,640,489, incorporated herein in its entirety by reference, and curing for 1200 sec. Polymerization occurred under a nitrogen purge and was photoinitiated with UV light or with visible light generated with a Philips TL 20W/03T fluorescent, and an appropriate initiator such as CGI 1850. After curing, the molds were opened, and the lenses were released into a 1:1 blend of water and ethanol, then leached in ethanol or isopropanol/deionied water to remove any residual monomers and diluent. Finally the lenses were equilibrated in physiological borate-buffered saline.

Lenses 8 and 14 were made as follows. 12.5 g KOH were added to 350 g of 20 mole propoxylate of methyl glucose available from Americol Corporation as GLUCAM.TM. P-20 in a high temperature reactor. The mixture was heated to 105.degree. C., stirred for 10 min. with nitrogen sparging, and then pulling vacuum. After repeating the sparge/vacuum two more times, the pressure was allowed to rise to 10 psi and temperature was increased to 125.degree. C. 1922 g propylene oxide were added gradually over 7 hours while maintaining a pressure of 30-40 psi and temperature of 135.degree. C. After continuing agitation overnight, 947 g ethylene oxide were added following a similar procedure. The product was neutralized with 9.1 g phosphoric acid and filtered with dicalite to give a slightly hazy liquid with a hydroxyl number if 28.3 mg KOH/g.

To a solution of 200 g of this product was added 21.0 g triethylamine and 342 mg N,N-dimethylaminopyridine in 600 g dry ethylene glycol dimethyl at 40.degree. C. 32.1 g of methacrylic anhydride in 250 g ethylene glycol dimethyl ether were added drop-wise to the reaction flask over a 7-8 hour period. The reaction was continued at 40.degree. C. for 7 days.

The reaction temperature was decreased to 25.degree. C. and 100 ml deionized water were added. The pH of the reaction mixture was adjusted to 7.0 using a 5% aqueous hydrochloric acid solution. 600 g of AMBERLITE.TM. IRA 96 were added and the mixture stirred for 11/2 hours. The AMEBRLITE.TM. IRA 96 was removed by filtration and the mixture volatilized at 30-35.degree. C. under reduced pressure.

Approximately 1 L chloroform was added and the resulting liquid was washed with an equal volume of 5% aqueous solution of sodium bicarbonate.times.2 and with saturated sodium chloride.times.1. The organic layer was passed through a 400 g silica bed. 100 mg of 4-methoxyphenol were added and the chloroform removed under pressure to remove residual chloroform and yield a macromer.

A blend was made of 11.2% of the macromer, 40% TRIS, 28% DMA, 0.8% DAROCUR.TM. 1173 (2-hydroxy-2-methyl-1-phenyl-propan-1-one) and 20% 1-hexanol. The blend was cured in contact lens molds by exposure to UV light for 30 min. The molds were opened and the lenses

released into a blend of isopropanol and water, rinsed with isopropanol, and placed into borate buffered saline.

The lenses were dried overnight in a clean room. The dried lenses were coated with diethylene glycol vinyl ether using pulsed plasma vapor deposition. The lenses were placed onto a tray concave side up, the tray was placed into a plasma chamber, and the lenses were subjected to 2 min. continuous wave argon plasma at 100 w and 200 m torr. Following the argon plasma, the lenses were subjected to a diethylene glycol vinyl ether pulsed plasma for 15 min. at 100 W and 70 m torr with a plasma on/off cycle of 10/200 msec. The lenses then were flipped so that the convex side faced upwardly and the process was repeated. The lenses were pulled from the chamber and re-hydrated in borate buffered saline packing solution.

The following lenses were used:

Lens 1–daily wear lenses coated with poly(acrylic acid) made of 17.98 wt percent macromer, 21.00 wt percent TRIS, 25.50 wt percent DMA, 21.00 wt percent mPDMS, 2.00 wt percent NORBLOC (2-(2′-hydroxy-5-methacrylyloxyethylphenyl-2H-benzotriazole), 1.00 wt percent CGI 1850 ((1:1 [wt] blend of 1-hydroxycyclohexyl phenyl) ketone and bis(2,6-dimethoxybenzoyl)-2,4,-4-trimethylpentyl phosphine oxide), 1.50 wt percent TEGDMA, 5.00 wt percent HEMA, 0.02 wt percent Blue HEMA (the reaction product of reactive blue number 4 and HEMA, as described in Example 4 of U.S. Pat. No. 5,944,853), 5.00 wt percent PVP, 20 wt percent D30 diluent.

Lens 2–daily wear coated with poly(acrylic acid) and made of 17.98 wt percent Macromer, 14.00 wt percent TRIS, 26 wt percent DMA, 28.00 wt percent mPDMS, 2.00 wt percent NORBLOC, 1.00 wt percent CGI 1850, 1.00 wt percent TEGDMA, 5.00 wt percent HEMA, 0.02 wt percent Blue HEMA, 5.00 wt percent PVP, 20 wt percent D30 diluent.

Lens 3–daily wear lenses made of the material of Lens 2.

Lens 4–daily wear, polyacrylamide coated using EDC lenses, made of the same material as Lens 2.

Lens 5–FOCUS.RTM. NIGHT & DAY daily wear lens, plasma coated, made of lotrafilcon A.

Lens 6–PUREVISION.RTM. daily wear, plasma coated, made of balafilcon A.

Lens 7–daily wear, poly(acrylic acid) coated using EDC lenses made of the same material as Lens 2.

Lens 8–daily wear, plasma coated lenses made with GLUCAM.TM. P-20.

Lens 9–extended wear, PUREVISION.RTM. plasma coated, lenses made of balafilcon A.

Lens 10–extended wear, poly(acrylic acid) coated using EDC lenses made of the same material as Lens 2.

Lens 11–extended wear, poly(acrylic acid) coated using EDC lenses made of the same material as Lens 2.

Lens 12–extended wear, polyacrylamide coated lenses made as the same material as Lens 2.

Lens 13–extended wear, uncoated lenses made of the material same material as Lens 2.

Lens 14–extended wear, plasma coated lenses made with GLUCAM.TM. P-20.

Clinical testing of lenses of each of these materials was carried out as single masked, contra-lateral studies according to the following procedure. Test subjects were soft contact lens wearers. The subjects were fitted with the study lenses and sent home with the lenses with instructions to wear the lenses either for daily or extended wear. All subjects in the daily wear lens studies were given an approved multi-purpose lens care solution and instructions for cleaning, rinsing, and disinfecting of the lenses.

Lenses 1 through 4 and 7 through 14 were worn for 1 week. Lenses 5 and 6 were worn for 2 weeks, but the measurements in the Table are based on 1 week wear. For the daily wear lenses, subjects inserted the lenses in the morning and removed them at night followed by storage in the approved lens care solution overnight. For extended wear lenses, the lenses were inserted on day 1 and removed on day 7. All subjects were permitted to remove their lenses when necessary for rinsing with preservative-free saline.

After 7 days, the subjects’ eyes were then examined for visual acuity, back-trapped debris, corneal and conjunctival staining, and conjunctival hyperemia. SEALs incidence was measured by examining the subjects’ eyes for grade 4, arc-shaped staining of the cornea accompanied, or unaccompanied, by epithelial splitting, corneal infiltrates, or both.

Superior epithelial arcuate lesions were defined as grade 4-type arc-shaped staining in the superior quadrant of the cornea, which staining also may be accompanied by epithelial splitting, corneal infiltrates, or both. A suspected lesion, or superior arcuate staining, was defined as grade 2 or 3-type arc-shaped staining in the superior quadrant of the cornea. The rates stated in the Table are the percentage of patients who develop either a lesion or a suspected lesion during the course of the study. Corneal staining was performed using a slit lamp biomicroscope with a cobalt blue illumination source, a 312 wratten filter and 1% minims sodium fluorescein. The slit lamp beam was set to a height of 6 mm and a width of 2 mm with a magnification of 16-20.times.. The following scale was utilized to determine the type and grade of the corneal staining: grade 1, individual or isolated cell loss; grade 2, small aggregates of cells; grade 3, coalesced aggregates; and grade 4, cell loss in excess of 1 mm.

Back-trapped debris was measured using a slit lamp with a beam set to a 2 mm width and a 6 mm height with a magnification between 16 and 20.times.. Back-trapped debris appeared in a variety of forms including, without limitation, as flaked white or off-color spots, or opaque or off-white spherical spots or streaks in the post-tear film. Back-trapped debris was differentiated from deposits that moved with the lens. On the table is shown the percentage of lens wearers experiencing no back-trapped debris or a slight amount.

The dynamic contact angle was measured as follows. Five samples of each lens type were prepared by cutting out a center strip approximately 5 mm in width and equilibrating the strip in borate buffered saline solution for more than 30 min. Dynamic contact angles of the strips were determined using a Cahn DCA-315 micro-balance. Each sample was cycled.times.4 in borate buffered saline and the cycles were averaged to obtain the advancing and receding contact angles for each lens. The contact angles of the 5 lenses were then averaged to obtain the mean contact angle for the set.

Tensile modulus was determined as follows. Twelve lenses were cut into dog-bone shapes and the modulus and elongation to break were measured using and INSTRON.TM. Model 1122 tensile tester. The lenses were hydrated, using their original packing solution, immediately prior to undergoing testing. The tensile modulus of the 12 lenses were averaged to obtain the mean modulus for the set. The results are shown below on the Table.

TABLE-US-00001 TABLE 1 Subjects Subjects LJ Back- in in Center Stiffness trapped Contact Clinical Clinical Mod. CT.sup.A Stiffness (psi- Seal Debris Angle SEAL BTD Lens (psi) (.mu.m) (psi mm.sup.2) LJT.sup.B mm.sup.2) (%) (“BTD”) (deg.) Study Study 1 110 124 1.69 224 5.52 10 0.89 57 20 22 2 88 90 0.71 222 4.34 0 1.00 <55 22 22 3 89.5 70 0.44 215 4.14 0 .90 70 20 20 4 87.3 77 0.52 215 4.04 0 1.00 <55 30 30 5 238 80 1.52 165 6.48 5.sup.C 0.72 67 — 23 6 155 90 1.26 93 1.33 5.sup.C 1.00 117 — 25 7 88 170 2.54 238 4.98 33 0.86 <55 30 30 8 73 68 0.34 210 3.22 0 1.0 81 29 29 9 155 90 1.26 92.5 1.33 11 0.72 117 18 18 10 88 90 0.71 222 4.34 0 0.83 <55 18 18 11 81 70 0.40 215 3.74 0 0.80 <55 25 25 12 87 70 0.43 215 4.04 0 0.75 <55 28 28 13 86 70 0.42 215 3.95 0 0.35 70 20 30 14 73 68 0.34 210 3.22 0 1.0 81 36 36 .sup.ACenter thickness. .sup.BLenticular junction thickness. .sup.CSweeney, D. B., “Comparative Incidence of SEALs With High Dk Soft Lenses”, Physiology and Pathophysiology, page 17 (August 1999).

The results shown on Table 1 demonstrate that lenses of the invention exhibit low or no SEALs and minimal back-trapped debris formation. Lenses 1, 5-7 and 9 are comparative examples showing that when lenses fail to meet the thickness and wettability criteria, SEALs and back-trapped debris are present in unacceptable levels.

1. A polymerizable composition comprising .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly(trifluoropropylmethylsiloxane- )-poly(.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), N-vinyl-N-methylacetamide, methylmethacrylate, ethylene glycol dimethacrylate, allyloxy alcohol, and a free radical initiator, which when formed into a lens body has an equilibrium water content of from about 40% to about 65% by weight, characterized in that at least one of the following conditions are met: (i) about 34 percent by weight .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly(trifluoropropylmethylsiloxane- )-poly(.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), (ii) about 46 percent by weight N-vinyl-N-methylacetamide, (iii) about 17 percent by weight methylmethacrylate, (iv) about 0.5 percent by weight ethylene glycol dimethacrylate, and (v) about 1 percent by weight allyloxy alcohol.

2. The polymerizable composition of claim 1, further comprising an ultraviolet absorber, a tinting agent, or a combination thereof.

3. The polymerizable composition of claim 2, wherein said ultraviolet absorber is 2-hydroxy-4-acryloyloxyethoxy benzophenone.

4. The polymerizable composition of claim 2, wherein said tinting agent is a phthalocyanine pigment.

5. The polymerizable composition of claim 1, wherein said free radical initiator is 2,2′-azobisisobutyronitrile.

6. The polymerizable composition of claim 1, further comprising one or more of the following: (vi) about 0.9 percent by weight 2-hydroxy-4-acryloyloxyethoxy benzophenone, (vii) about 0.1 percent by weight phthalocyanine blue, and (viii) about 0.3 weight percent free radical initiator.

7. The polymerizable composition of claim 1, comprising about 34 percent by weight .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly(trifluoropropylmethylsiloxane- )-poly(.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), about 46 percent by weight N-vinyl-N-methylacetamide, about 17 percent by weight methylmethacrylate, about 0.5 percent by weight ethylene glycol dimethacrylate, about 1 percent by weight allyloxy alcohol, about 0.9 percent by weight 2-hydroxy-4-acryloyloxyethoxy benzophenone, about 0.1 percent by weight phthalocyanine blue, and about 0.3 percent by weight 2,2′-azobisisobutyronitrile.

8. The polymerizable composition of claim 1, absent a polyalkylene oxide silicone extractable component.

9. A silicone hydrogel contact lens produced from a polymerizable composition comprising .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly(trifluoropropylmethylsiloxane- )-poly(.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), N-vinyl-N-methylacetamide, methylmethacrylate, ethylene glycol dimethacrylate, allyloxy alcohol, and a free radical initiator, characterized in that at least one of the following conditions are met: (i) about 34 percent by weight .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly(trifluoropropylmethylsiloxane- )-poly(.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), (ii) about 46 percent by weight N-vinyl-N-methylacetamide, (iii) about 17 percent by weight methylmethacrylate, (iv) about 0.5 percent by weight ethylene glycol dimethacrylate, and (v) about 1 percent by weight allyloxy alcohol.

10. A silicone hydrogel contact lens formed from a composition comprising .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly(trifluoropropylmethylsiloxane- )-poly(.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), N-vinyl-N-methylacetamide, methylmethacrylate, ethylene glycol dimethacrylate, allyloxy alcohol, and a free radical initiator and said lens substantially free of extractable components, characterized in that at least one of the following conditions are met: (i) about 34 percent by weight .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly(trifluoropropylmethylsiloxane- )-poly(.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), (ii) about 46 percent by weight N-vinyl-N-methylacetamide, (iii) about 17 percent by weight methylmethacrylate, (iv) about 0.5 percent by weight ethylene glycol dimethacrylate, and (v) about 1 percent by weight allyloxy alcohol.

11. A silicone hydrogel contact lens produced by polymerizing a polymerizable composition comprising .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly(trifluoropropylmethylsiloxane- )-poly(.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), N-vinyl-N-methylacetamide, methylmethacrylate, ethylene glycol dimethacrylate, allyloxy alcohol, and a free radical initiator to form a pre-extracted polymerized silicone hydrogel contact lens comprising extractable components, extracting said extractable components from the pre-extracted contact lens to form an extracted polymerized lens product, and hydrating the extracted polymerized lens product to form a silicone hydrogel contact lens, characterized in that at least one of the following conditions are met: (i) about 34 percent by weight .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly(trifluoropropylmethylsiloxane- )-poly(.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), (ii) about 46 percent by weight N-vinyl-N-methylacetamide, (iii) about 17 percent by weight methylmethacrylate, (iv) about 0.5 percent by weight ethylene glycol dimethacrylate, and (v) about 1 percent by weight allyloxy alcohol.

12. The silicone hydrogel contact lens of claim 11, having an equilibrium water content in the range of about 42% to about 50% by weight and an oxygen permeability (D.sub.k.times.10.sup.-11) ranging from about 80-100 barrers.

13. The silicon hydrogel contact lens of claim 11, having a modulus from about 0.6 to about 1.2 MPa.

14. The silicone hydrogel contact lens of claim 11, wherein said polymerizing comprises heating the polymerizable composition to a temperature greater than about 55.degree. C.

15. A non-surface treated silicone hydrogel contact lens of claim 11.

16. A method for producing a polymerizable silicone hydrogel contact lens precursor composition, said method comprising combining .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly(trifluoropropylmethylsiloxane- )-poly(.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), N-vinyl-N-methylacetamide, methylmethacrylate, ethylene glycol dimethacrylate, allyloxy alcohol, and a free radical initiator, to thereby produce a polymerizable silicone hydrogel contact precursor composition, wherein said combining step comprises combining about 34 percent by weight .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly(trifluoropropylmethylsiloxane- )-poly(.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), about 46 percent by weight N-vinyl-N-methylacetamide, about 17 percent by weight methylmethacrylate, about 0.5 percent by weight ethylene glycol dimethacrylate, about 1 percent by weight allyloxy alcohol, about 0.9 percent by weight 2-hydroxy-4-acryloyloxyethoxy benzophenone, about 0.1 percent by weight phthalocyanine blue, and about 0.3 percent by weight 2.2′-azobisisobutyronitrile.

17. The method of claim 16, further comprising in said combining step, an ultraviolet absorber, a tinting agent, or a combination thereof.

18. The method of claim 17, wherein said ultraviolet absorber is 2-hydroxy-4-acryloyloxyethoxy benzophenone and said tinting agent is a phthalocyanine pigment.

19. The method of claim 16, further comprising polymerizing the polymerizable lens precursor composition to form a pre-extracted polymerized silicone hydrogel contact lens.

20. The method of claim 19, further comprising placing said polymerizable lens precursor composition prior to said polymerizing in a non-polar resin contact lens mold.

21. The method of claim 20, further comprising extracting the pre-extracted polymerized contact lens to form an extracted polymerized lens product substantially absent extractable components, and hydrating the extracted polymerized lens product to form a silicone hydrogel contact lens.

22. The polymerizable composition of claim 1, wherein said lens body had at least 10% (w/w) extractables removed by extraction.

23. A silicone hydrogel contact lens produced from a polymerizable composition comprising .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly(trifluoropropylmethylsiloxane- )-poly(.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), N-vinyl-N-methylacetamide, methylmethacrylate, ethylene glycol dimethacrylate, allyloxy alcohol, and a free radical initiator, wherein said lens had at least 10% (w/w) extractables removed by extraction, characterized in that at least one of the following conditions are met: about 34 percent by weight .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly(trifluoropropylmethylsiloxane- )-poly(.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), (ii) about 46 percent by weight N-vinyl-N-methylacetamide, (iii) about 17 percent by weight methylmethacrylate, (iv) about 0.5 percent by weight ethylene glycol dimethacrylate, and (v) about 1 percent by weight allyloxy alcohol
Contact Lens Description
FIELD

The present invention is directed to silicone hydrogel ophthalmic devices and related compositions and methods, among other aspects. More particularly, the present invention relates to wettable molded silicone hydrogel contact lenses, and related compositions and methods.

BACKGROUND

Silicone hydrogel contact lenses have become popular due to the ability of contact lens wearers to wear such lenses on their eyes for longer times compared to non-silicone hydrogel contact lenses. For example, depending on the particular lens, silicone hydrogel contact lenses can be worn or prescribed for daily wear, weekly wear, biweekly wear, or monthly wear. Benefits to lens wearers associated with silicone hydrogel contact lenses can be attributed, at least in part, to the combination of hydrophilic components and the hydrophobic properties of silicon-containing polymeric materials of the contact lenses.

Non-silicone hydrogel contact lenses, such as 2-hydroxyethylmethacrylate (HEMA) based hydrogel contact lenses, are often produced in non-polar resin contact lens molds, for example, contact lens molds produced from polyolefin-based resins. Lens precursor compositions for non-silicone hydrogel contact lenses are polymerized in non-polar resin contact lens molds to produce HEMA-based polymeric or polymerized lens products. Due to the hydrophilic nature of the polymeric components of HEMA-based contact lenses, the HEMA-based lenses are ophthalmically compatible and have ophthalmically acceptable surface wettabilities, even in spite of being produced using non-polar resin molds.

In contrast, existing silicone hydrogel contact lenses obtained from non-polar resin molds have hydrophobic lens surfaces. In other words, the surfaces of such silicone hydrogel contact lenses have low wettability and therefore are not ophthalmically compatible or ophthalmically acceptable. For example, such silicone hydrogel contact lenses may be associated with less than desirable features such as increased lipid deposition, protein deposition, lens binding to the ocular surface, and general irritation to a lens wearer.

In an effort to overcome these problems, surface treatment or surface modification of silicone hydrogel contact lenses or lens products has been employed in an attempt to increase the hydrophilicity and wettability of the lens surfaces. Examples of surface treatment of silicone hydrogel lenses include coating a surface of the lens, adsorbing chemical species onto the surface of the lens, and altering the chemical nature or electrostatic charge of chemical groups on the surface of the lens. Surface treatments have been described which include using a plasma gas to coat the surface of a polymerized lens, or using a plasma gas on a contact lens mold surface to treat the mold prior to forming a polymerized lens. Unfortunately, several drawbacks are associated with this approach. Surface treatment of contact lenses requires more machinery and time to produce contact lenses compared to manufacturing methods that do not use surface treatments or modifications. In addition, surface treated silicone hydrogel contact lenses can exhibit a decreased surface wettability as the lens is being worn and/or handled by the lens wearer. For example, increased handling of a surface treated lens can result in the hydrophilic surface being degraded or worn away.

An alternative approach to increasing the wettability and ophthalmic compatibility of silicone hydrogel lenses is to polymerize a silicone hydrogel contact lens precursor composition in the presence of a second composition that comprises a polymeric wetting agent, such as polyvinylpyrollidone (PVP). These types of lenses are referred to herein as silicone hydrogel contact lenses with polymeric internal wetting agents, and typically comprise an interpenetrating polymer network (IPN) that includes a high molecular weight polymer, such as PVP. As understood by persons of ordinary skill in the art, an IPN refers to a combination of two or more different polymers, in network form, at least one of which is synthesized and/or cross-linked in the presence of the other without any covalent bonds between them. An IPN can be composed of two kinds of chains forming two separate networks, but in juxtaposition or interpenetrating. Examples of IPNs include sequential IPNs, simultaneous IPNs, semi-IPNs and homo-IPNs. Although silicone hydrogel contact lenses that include an IPN of a polymeric wetting agent avoid the problems associated with surface treatment, these lenses may not retain their ophthalmic compatibility, including surface wettability, for prolonged periods of time. For example, internal wetting agents, since they are not covalently bound to the other polymerized lens forming components, may leach out from the lens while being worn by a lens wearer, and thereby lead over time to a decreased surface wettability and increased discomfort to the lens wearer.

As an alternative to surface treatment or use of a polymeric wetting agent IPN, as described above, it has been found that silicone hydrogel contact lenses with ophthalmically acceptable surface wettabilities can be produced using polar resin molds instead of non-polar resin molds. For example, silicone hydrogel contact lenses formed in ethylene-vinyl alcohol or polyvinyl alcohol based molds have desirable surface wettabilities. One example of a useful polar resin used in the manufacture of contact lens molds for producing non-surface treated silicone hydrogel contact lenses free of an IPN of a polymeric wetting agent is a resin of ethylene-vinyl alcohol copolymers such as the ethylene-vinyl alcohol copolymer resin sold under the trade name SOARLITE.TM. by Nippon Gohsei, Ltd. In addition to its polarity, SOARLITE.TM. is described as possessing the following characteristics: extremely high mechanical strength, antistatic properties, low contractility when used in molding processes, excellent oil and solvent resistance, small coefficient of thermal expansion, and good abrasion resistance.

Although SOARLITE.TM.-based molds provide a desirable alternative for producing ophthalmically compatible silicone hydrogel contact lenses without the use of a surface treatment or a polymeric wetting agent IPN, SOARLITE.TM. molds are less deformable or flexible than non-polar resin molds, such as polypropylene molds, and are relatively more difficult to work with compared to non-polar resin molds.

In view of the above, it can be seen that a need exists for ophthalmically compatible silicone hydrogel contact lenses that can be more easily produced compared to silicone hydrogel contact lenses obtained from SOARLITE.TM. contact lens molds, and that do not require surface treatment or use of a polymeric wetting agent IPN, including a PVP IPN, to achieve ophthalmic compatibility. Additionally, it would be highly desirable to provide a method for producing an ophthalmically compatible silicone hydrogel contact lens, such as a silicone hydrogel contact lens having an ophthalmically compatible surface wettability, from non-polar resin or polyolefin-based contact lens mold members, which overcomes the disadvantages of current manufacturing approaches. That is to say, there is a need for an improved method for preparing an ophthalmically compatible silicone hydrogel contact lens that requires neither surface treatment of the resulting contact lens product nor the use of a polymeric wetting agent IPN as part of a polymerizable silicone hydrogel contact lens precursor composition to provide a lens product having features attributable to extended comfort. The present invention meets these needs.

SUMMARY

The contact lenses, lens products, compositions, and methods of the present invention address the needs and problems associated with existing silicone hydrogel contact lenses and their current methods of production. It has been surprisingly discovered that ophthalmically compatible silicone hydrogel contact lenses are obtained by combining certain components to provide a polymerizable composition, which, upon polymerization, provides a pre-extracted polymerized silicone hydrogel contact lens product having one or more particularly desirable features. In one or more embodiments, the hydrogel contact lens product possesses about 10% or more by weight extractable components pre-extraction. In certain embodiments, the extractable content of the pre-extracted silicone hydrogel contact lens product is at least about 20% by weight. For example, a pre-extracted silicone hydrogel contact lens product may have an extractable content from about 22% to about 30% by weight. In at least one specific embodiment, a pre-extracted silicone hydrogel contact lens product has an extractable content of about 26% by weight. In one or more embodiments of the present products and methods, provided herein is a silicone hydrogel contact lens product that does not employ a polyalkylene oxide silicone extractable component, but which advantageously leads to compositions and lenses having distinct and desirable characteristics when compared to existing lenses.

Features of the silicone hydrogel contact lens provided herein include an ophthalmically acceptable surface wettability, as described herein. Additionally, the silicone hydrogel contact lenses of the present invention have an oxygen permeability, a surface wettability, a modulus, a water content, ionoflux, and design which permit the lenses to be comfortably worn on a patient’s eye for extended periods of time, such as for at least a day, at least a week, at least two weeks, or about a month without requiring removal of the lens from the eye.

In one aspect, the present invention is directed to a polymerizable silicone hydrogel contact lens precursor composition. Such precursor compositions are effective to form silicone hydrogel contact lenses.

In one aspect in particular, provided herein is a polymerizable composition comprising, consisting essentially of, or consisting entirely of, the following components: .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly(trifluoropropylmethylsiloxane- )-poly (.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), N-vinyl-N-methylacetamide, methylmethacrylate, ethylene glycol dimethacrylate, allyloxy alcohol, and a free radical initiator.

In one or more embodiments, the polymerizable composition further comprises an ultraviolet absorber, such as 2-hydroxy-4-acryloyloxyethoxy benzophenone, among others.

In one or more additional embodiments, the polymerizable composition further comprises a tinting agent, for example, a phthalocyanine pigment such as phthalocyanine blue, among others.

In yet one or more further embodiments, the free radical initiator comprised in the polymerizable composition is 2,2′-azobisisobutyronitrile.

The invention further includes any one or more of the polymerizable compositions described above comprising about 34 percent by weight .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly (trifluoropropylmethylsiloxane)-poly (.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane).

In yet one or more additional embodiments, the polymerizable composition may comprise any one or more of the following: (i) about 46 percent by weight N-vinyl-N-methylacetamide, (ii) about 17 percent by weight methylmethacrylate, (iii) about 0.5 percent by weight ethylene glycol dimethacrylate, and (iv) about 1 percent by weight allyloxy alcohol.

In yet one or more additional embodiments, the polymerizable composition comprises about 0.9 percent by weight 2-hydroxy-4-acryloyloxyethoxy benzophenone.

In yet one or more further embodiments, the polymerizable composition comprises about 0.1 percent by weight phthalocyanine blue.

In yet one or more further embodiments, the polymerizable composition comprises about 0.3 weight percent free radical initiator.

In yet one another particular embodiment, the polymerizable composition comprises about 34 percent by weight .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly (trifluoropropylmethylsiloxane)-poly (.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), about 46 percent by weight N-vinyl-N-methylacetamide, about 17 percent by weight methylmethacrylate, about 0.5 percent by weight ethylene glycol dimethacrylate, about 1 percent by weight allyloxy alcohol, about 0.9 percent by weight 2-hydroxy-4-acryloyloxyethoxy benzophenone, about 0.1 percent by weight phthalocyanine blue, and about 0.3 percent by weight 2,2′-azobisisobutyronitrile.

In yet another embodiment, provided is any one or more of the polymerizable compositions described herein absent a polyalkylene oxide silicone extractable component.

In yet another aspect, provided is a silicone hydrogel contact lens produced from a polymerizable composition as provided herein.

Also provided is a silicone hydrogel contact lens formed from a polymerizable composition as described herein, substantially free of extractable components.

Also forming part of the invention is a silicone hydrogel contact lens produced by polymerizing a polymerizable composition as provided herein to form a pre-extracted polymerized silicone hydrogel contact lens comprising extractable components, extracting the extractable components from the pre-extracted contact lens to form an extracted polymerized lens product, and hydrating the extracted polymerized lens product to form a silicone hydrogel contact lens.

In one or more embodiments, a silicone hydrogel contact lens produced as described above possesses an equilibrium water content in the range of about 42% to about 50% by weight and an oxygen permeability (D.sub.k.times.10.sup.-11) ranging from about 80-110 barrers.

In one or more additional embodiments, a silicon hydrogel contact lens produced as described above possesses a modulus from about 0.6 to about 1.2 MPa.

In yet one or more further embodiments, provided is a silicone hydrogel contact lens produced as described above, where the polymerizing step comprises heating the polymerizable composition to a temperature greater than about 65.degree. C.

In yet another aspect, provided herein is a silicone hydrogel contact lens having an equilibrium water content in the range of about 42% to about 50% by weight, an oxygen permeability (D.sub.k.times.10.sup.-11) ranging from about 80-110 barrers, a modulus from about 0.6 to about 1.2 MPa, an ionoflux from about 1-5 (.times..sup.10-3 mm.sup.2/min), an advancing contact angle from about 52 to about 62 degrees, a receding contact angle from about 40 to 60 degrees, and a hysteresis from about 5 to about 15 degrees.

In one or more embodiments, a silicon hydrogel contact lens as described herein is additionally characterized by a lens body having a rounded peripheral edge.

In yet one or more additional embodiments, a silicone hydrogel contact lens of the invention may be (i) a spheric lens, (ii) an aspheric lens, (iii) a monofocal lens, (iv) a multifocal lens, or (v) a rotationally stabilized toric contact lens.

In yet one or more further embodiments, a silicone hydrogel contact lens of the invention is in a sealed package.

In yet one or more additional embodiments, a silicone hydrogel contact lens as provided herein is non-surface treated.

In yet another aspect, provided herein is a method for producing a polymerizable silicone hydrogel contact lens precursor composition. In one or more embodiments, the method comprises combining .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly (trifluoropropylmethylsiloxane)-poly (.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), N-vinyl-N-methylacetamide, methylmethacrylate, ethylene glycol dimethacrylate, allyloxy alcohol, and a free radical initiator, to thereby produce a polymerizable silicone hydrogel contact precursor composition.

In one or more embodiments of the method, the combining step additionally includes an ultraviolet absorber.

In yet one or more particular embodiments, the combining step additionally includes 2-hydroxy-4-acryloyloxyethoxy benzophenone.

In yet one or more additional embodiments of the method, the combining step additionally includes a tinting agent, for instance, a phthalocyanine pigment such as phthalocyanine blue.

In yet one or more particular embodiments of the method, the free radical initiator is 2,2′-azobisisobutyronitrile.

In yet one or more particular embodiments, the method comprises combining: (i) about 30 to 40 percent by weight .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly (trifluoropropylmethylsiloxane)-poly (.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), (ii) about 40 to 50 percent by weight N-vinyl-N-methylacetamide, (iii) about 10 to 25 percent by weight methylmethacrylate, and (iv) less than about 5% by weight combined of ethylene glycol dimethacrylate, allyloxy alcohol, 2-hydroxy-4-acryloyloxyethoxy benzophenone, phthalocyanine blue, and 2,2′-azobisisobutyronitrile.

In yet one or more additional embodiments of the method, the combining step comprises combining about 34 percent by weight .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly (trifluoropropylmethylsiloxane)-poly (.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), about 46 percent by weight N-vinyl-N-methylacetamide, about 17 percent by weight methylmethacrylate, about 0.5 percent by weight ethylene glycol dimethacrylate, about 1 percent by weight allyloxy alcohol, about 0.9 percent by weight 2-hydroxy-4-acryloyloxyethoxy benzophenone, about 0.1 percent by weight phthalocyanine blue, and about 0.3 percent by weight 2,2′-azobisisobutyronitrile to thereby provide a polymerizable silicone hydrogel contact lens precursor composition.

In yet one or more further embodiments, the method further comprises polymerizing the polymerizable lens precursor composition to form a pre-extracted polymerized silicone hydrogel contact lens.

In one or more particular embodiments of the method, the polymerizing step comprises heating the polymerizable lens precursor composition.

In yet one or more additional embodiments, the method further comprises, prior to the polymerization step, placing the polymerizable lens precursor composition in a non-polar resin contact lens mold.

In yet one or more further embodiments, the method further comprises extracting the pre-extracted polymerized contact lens to form an extracted polymerized lens product substantially absent extractable components, and hydrating the extracted polymerized lens product to form a silicone hydrogel contact lens.

In yet another aspect, provided herein is a silicone hydrogel contact lens comprising the reaction product of a polymerizable composition as described herein, substantially free of extractable components.

Additional embodiments of the present lenses, lens products, compositions and methods will be apparent from the following description, drawings, examples, and claims. As can be appreciated from the foregoing and following description, each and every feature described herein, and each and every combination of two or more of such features, is included within the scope of the present invention provided that the features included in such a combination are not mutually inconsistent. In addition, any feature or combination of features may be specifically excluded from any embodiment of the present invention. Additional aspects and advantages of the present invention are set forth in the following description and claims, particularly when considered in conjunction with the accompanying examples and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an exemplary method for producing a silicone hydrogel contact lens.

FIG. 2 is a block diagram illustrating compositions, lens products, and contact lenses of the invention.

DETAILED DESCRIPTION

The present invention now will be described more fully hereinafter. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

Definitions

It must be noted that, as used in this specification, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a “contact lens” includes a single lens as well as two or more of the same or different lenses, reference to a “precursor composition” refers to a single composition as well as two or more of the same or different compositions, and the like.

In describing and claiming the present invention, the following terminology will be used in accordance with the definitions described below.

As used herein, the term “hydrogel” refers to a polymeric material, typically a network or matrix of polymer chains, capable of swelling in water or becoming swollen with water. The network or matrix may or may not be cross-linked. Hydrogels refer to polymeric materials, including contact lenses, that are water swellable or are water swelled. Thus, a hydrogel may be (i) unhydrated and water swellable, or (ii) partially hydrated and swollen with water, or (iii) fully hydrated and swollen with water.

The term “substituted” as in, for example, “substituted alkyl,” refers to a moiety (e.g., an alkyl group) substituted with one or more non-interfering substituents, such as, but not limited to: C.sub.3-C.sub.8 cycloalkyl, e.g., cyclopropyl, cyclobutyl, and the like; halo, e.g., fluoro, chloro, bromo, and iodo; cyano; alkoxy, lower phenyl; substituted phenyl; and the like. For substitutions on a phenyl ring, the substituents may be in any orientation (i.e., ortho, meta, or para).

The term “silicone hydrogel” or “silicone hydrogel material” refers to a particular hydrogel that includes a silicon (Si) component or a silicone component. For example, a silicone hydrogel is typically prepared by combining a silicon-containing material with conventional hydrophilic hydrogel precursors. A silicone hydrogel contact lens is a contact lens, including a vision correcting contact lens, which comprises a silicone hydrogel material. The properties of a silicone hydrogel contact lens are distinct from conventional hydrogel-based lenses.

A “silicone-containing component” is a component that contains at least one [--Si--O--Si] linkage, in a monomer, macromer or prepolymer, wherein each silicon atom may optionally possess one or more organic radical substituents (R.sub.1, R.sub.2) or substituted organic radical substituents that may be the same as different, e.g., –SiR.sub.1R.sub.2O–.

“Optional” or “optionally” means that the subsequently described circumstance may or may not occur, so that the description includes instances where the circumstance occurs and instances where it does not.

“Molecular mass” in the context of a polymer of the invention refers to the nominal average molecular mass of a polymer, typically determined by size exclusion chromatography, light scattering techniques, or intrinsic velocity determination in 1,2,4-trichlorobenzene. Molecular weight in the context of a polymer can be expressed as either a number-average molecular weight or a weight-average molecular weight, and in the case of vendor-supplied materials, will depend upon the supplier. Typically, the basis of any such molecular weight determinations can be readily provided by the supplier if not provided in the packaging material. Typically, references herein to molecular weights of macromers or polymers herein refer to the weight average molecular weight. Both molecular weight determinations, number-average and weight-average, can be measured using gel permeation chromatographic or other liquid chromatographic techniques. Other methods for measuring molecular weight values can also be used, such as the use of end-group analysis or the measurement of colligative properties (e.g., freezing-point depression, boiling-point elevation, or osmotic pressure) to determine number-average molecular weight or the use of light scattering techniques, ultracentrifugation or viscometry to determine weight-average molecular weight.

A “network” or “matrix” of a hydrophilic polymer typically means that crosslinks are formed between the polymer chains by covalent bonds or by physical bonds, e.g. hydrogen bonds.

A “hydrophilic” substance is one that is water-loving. Such compounds have an affinity to water and are usually charged or have polar side groups that attract water.

A “hydrophilic polymer” according to the present invention is defined as a polymer capable of swelling in water, however, not necessarily being soluble in water.

A “hydrophilic component” is a hydrophilic substance that may or may not be a polymer. Hydrophilic components include those that are capable of providing at least about 20%, for example, at least about 25% water content to the resulting hydrated lens when combined with the remaining reactive components.

As used herein, an “ophthalmically compatible silicone hydrogel contact lens” refers to a silicone hydrogel contact lens that can be worn on a person’s eye without the person experiencing or reporting substantial discomfort, including ocular irritation and the like. Ophthalmically compatible silicone hydrogel contact lenses have ophthalmically acceptable surface wettabilities, and typically do not cause or are not associated with significant corneal swelling, corneal dehydration (“dry eye”), superior-epithelial arcuate lesions (“SEALs”), or other significant discomfort.

“Substantially” or “essentially” or “about” means nearly totally or completely, for instance, 95% or greater of some given quantity.

“Substantially absent” or “substantially free” of a certain feature or entity means nearly totally or completely absent the feature or entity, for example, containing 5% or less of some given entity. For example, a composition that is substantially free of a certain entity can contain less than about 5%, or less than about 4%, less than about 3%, less than about 2%, or even less than about 1% of some given entity.

“Alkyl” refers to a hydrocarbon chain, typically ranging from about 1 to 20 atoms in length. Such hydrocarbon chains are preferably but not necessarily saturated and may be branched or straight chain, although typically straight chain is preferred. Exemplary alkyl groups include methyl, ethyl, propyl, butyl, pentyl, 1-methylbutyl, 1-ethylpropyl, 3-methylpentyl, and the like. As used herein, “alkyl” includes cycloalkyl when three or more carbon atoms are referenced.

An “oligomer” is a molecule consisting of a finite number of monomer subunits, and typically consists of from about 2 to about 8 monomer subunits.

“Lower alkyl” refers to an alkyl group containing from 1 to 6 carbon atoms, and may be straight chain or branched, as exemplified by methyl, ethyl, n-butyl, i-butyl, t-butyl.

Additional definitions may also be found in the sections which follow.

Overview

As discussed previously, the invention provided herein is based, at least in part, upon the discovery/formulation of ophthalmically compatible silicone hydrogel contact lenses that can be prepared using methods which avoid the problems associated with polar resin molds, avoid the need for elaborate and expensive post-polymerization procedures, and circumvent the problems associated with IPNs of polymeric wetting agents. Moreover, the formulations provided herein do not require more than about 30% of a removable or extractable component that is essentially unincorporated into the polymerized silicone hydrogel contact lens product, and is removed, along with other unreacted components, from the resulting molded contact lens product by extraction. For example, ophthalmically acceptable silicone hydrogel contact lenses can be obtained from pre-extracted polymerized silicone hydrogel contact lens products that have an extractable content of at least 10% and less than about 30% of a dehydrated extracted silicone hydrogel contact lens, as discussed herein. In certain embodiments, the lens formulations are free of a polyalkylene oxide silicone component.

Specifically, a method for producing ophthalmically compatible silicone hydrogel contact lenses includes incorporating into a polymerizable silicone contact lens precursor composition a particular combination of components. These materials impart desirable features to the resulting final contact lens to provide an extracted contact lens product, which is then hydrated to result in a final silicone hydrogel contact lens having an ophthalmically acceptable surface wettability, as well as other beneficial features as described herein.

These and other notable aspects of the invention are described and exemplified in detail in the sections that follow.

Components of a Polymerizable Silicone Hydrogel Contact Lens Precursor Composition

The silicone hydrogel contact lenses of the invention are typically produced from what is referred to herein as a “polymerizable silicone hydrogel contact lens precursor composition” or a “precursor composition”. A precursor composition is a mixture of various reagents used to make a silicone hydrogel contact lens, i.e., a reaction mixture, prior to reaction, which in the present case, is polymerization.

A precursor composition in accordance with the invention typically comprises at least the following components: .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly (trifluoropropylmethylsiloxane)-poly (.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), N-vinyl-N-methylacetamide, methylmethacrylate, ethylene glycol dimethacrylate, allyloxy alcohol, and a free radical initiator. In certain embodiments, the composition consists essentially of the foregoing components. In further embodiments, the compositions consists entirely of the foregoing components.

.alpha.-.omega.-Bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly (trifluoropropylmethylsiloxane)-poly (.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane)

The first component, .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly (trifluoropropylmethylsiloxane)-poly (.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), is a reactive fluoro-containing acryloyl silicone macromer, commonly referred to as “M3U” (CAS Registry Number of 697234-74-5). The macromer is a triblock polymer, i.e., comprising three different siloxane polymer blocks, as shown in the generalized structure below. The central block possesses a trifluoromethyl substituent, while acryloyl moieties are present at each of the termini.

##STR00001##

The variables n, m, and h correspond to the number of repeat units of each block, and each independently ranges from about 3 to about 200, while p, the number of ethylene oxide repeat units, ranges from about 2 to about 12. One particularly preferred macromer corresponding to the above structure is one where n ranges from 50 to 200, m ranges from 2 to 50, and h ranges from 1 to 15. In a particularly preferred embodiment, n is about 121, m is about 7.6, h is about 4.4, and p is about 7.4. M3U can be readily synthesized following the procedure set forth in International Patent Publication No. WO 2006/026474, Example 1.

The molecular weight of the silicone macromer component, i.e., M3U, typically ranges from about about 8,000 daltons to about 25,000 daltons, and preferably ranges from about 10,000 daltons to about 20,000 daltons, depending upon the values of the variables n, m, h, and p. One particularly preferred siloxane macromer for use in the present invention possesses a molecular weight of about 16,000 daltons. For example, a macromer may have a weight average molecular weight (Mw) of about 16,200 and a number average molecular weight (Mn) of about 12,800 daltons.

The polymerizable silicone hydrogel precursor compositions provided herein typically contain at least about 25% by weight of .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly trifluoropropylmethylsiloxane)-poly (.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), and more preferably contain at least about 30% by weight .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly (trifluoropropylmethylsiloxane)-poly (.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane). Even more preferably, the polymerizable compositions of the invention contain from about 25% to about 40% by weight .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly (trifluoropropylmethylsiloxane)-poly (.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), or most preferably, from about 30 to about 40% by weight .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly (trifluoropropylmethylsiloxane)-poly (.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane). One particularly preferred polymerizable composition comprises about 34% by weight .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly trifluoropropylmethylsiloxane)-poly (.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane).

N-Vinyl-N-methylacetamide

A polymerizable composition as provided herein additionally comprises N-vinyl-N-methylacetamide (VMA), a hydrophilic vinyl-containing (CH.sub.2.dbd.CH–) monomer. The structure of VMA corresponds to CH.sub.3C(O)N(CH.sub.3)–CH.dbd.CH.sub.2.

Additional hydrophilic vinyl-containing monomers that may be incorporated into the materials of the present lenses include the following: N-vinyl lactams (e.g. N-vinyl pyrrolidone (NVP)), N-vinyl-N-ethyl acetamide, N-vinyl-N-ethyl formamide, N-vinyl formamide, N-2-hydroxyethyl vinyl carbamate, N-carboxy-.beta.-alanine N-vinyl ester.

Preferably, N-vinyl-N-methylacetamide is present in the polymerizable composition in an amount ranging from about 35% to about 55% by weight of the precursor composition used to prepare the silicone lens product, and even more preferably is present in an amount ranging from about 40% to about 50% by weight of the precursor composition. Representative weights of N-vinyl-N-methylacetamide include the following: about 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, or 50% by weight of the precursor composition. In a preferred embodiment, a polymerizable composition as provided herein comprises about 46% by weight N-vinyl-N-methylacetamide.

Methyl Methacrylate (MMA)

A polymerizable precursor composition for preparing a silicone hydrogel contact lens product in accordance with the invention additionally comprises an acrylic monomer such as methyl methyacrylate.

Preferably, methyl methyacrylate is present in an amount ranging from about 10% to about 25% by weight of the precursor composition used to prepare the silicone hydrogel lens product, and even more preferably is present in an amount ranging from about 10% to about 22% by weight of the precursor composition. Illustrative weight percentages of methyl methyacrylate include the following, based on the overall precursor formulation include about 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, and 25%.

Ethylene Glycol Dimethacrylate (EGDMA)

The precursor composition additionally comprises an acrylate-functionalized ethylene oxide oligomer, that is to say, an ethylene oxide oligomer possessing from about 1 to about 8 contiguous ethylene oxide (CH.sub.2CH.sub.2O–) monomer subunits, and end-functionalized with a reactive group such as an acrylate. Preferably, the acrylate-functionalized ethylene oxide oligomer is an ethylene oxide monomer or 1-mer, and is homobifunctional, i.e., is end capped at each end with a methacrylate group. A generalized structure is provided below, where the variable s corresponds to the number of ethylene oxide monomers.

##STR00002##

In the preceding structure, s generally ranges from 1 to about 8, preferably from 1 to about 4. That is to say, preferred values of s include 1, 2, 3, 4, 5, 6, 7, and 8. Preferably, the acrylate-functionaled ethylene oxide oligomer is ethylene oxide dimethacrylate, where s has a value of 1.

Typically, the acrylate-functionalized ethylene oxide oligomer, i.e., EGDMA, is present in the precursor composition in relatively small amounts. For instance, the oligomer is present in the precursor composition an amount ranging from about 0.05% by weight to about 10% by weight, preferably from about 0.075% by weight to about 5% by weight. Representative amounts of the EGDMA component include the following: about 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, or 5% by weight of the precursor composition. In a preferred embodiment, a precursor composition of the invention comprises about 0.5 weight percent EGDMA.

Allyloxy Alcohol

In addition to the above, a polymerizable composition in accordance with the invention comprises a chain transfer reagent. A chain transfer reagent is one that promotes reaction between a radical species and a non-radical species. Preferred for use in the invention are allyloxy compounds, that is, a compound comprising one or more allyloxy moieties. Exemplary chain transfer reagents falling into this classification include include allyloxy alcohols, among others. Chain transfer agents may be used individually or as mixtures.

A compound comprising at least one allyloxy moiety possesses the following generalized structure:

##STR00003## where the boxed portion corresponds to the allyloxy moiety, and Q represents the remainder or residue of the parent molecule, e.g., an alcohol, or any organic small molecule, which, when taken together with the allyoxy moiety, is capable of functioning as a chain transfer agent. Preferably, Q is derived from an alcohol such as ethanol, propanol, butanol, and the like, or substituted versions thereof. Preferably, Q is the residue of ethanol, and possesses the structure (–CH.sub.2CH.sub.2OH), such that the chain transfer reagent corresponds to 2-allyloxyethanol.

The inventors have discovered that the inclusion of a chain transfer reagent such as an allyloxy compound is effective to provide extracted, hydrated silicone contact lens bodies having reduced variability in both dimensional and physical properties. Thus, addition of a chain transfer agent functions to “normalize” or “microtune” the precursor lens compositions, such that resulting populations of extracted, hydrated contact lenses typically possess a reduced batch to batch variability in any one or more of the following characteristics: equilibrium water content, oxygen permeability, static contact angle, dynamic contact angle (advancing contact angle or receding contact angle), hysteresis, refractive index, ionoflux, modulus, tensile strength and the like.

A batch or population as used herein refers to a plurality of contact lenses. It can be appreciated that improved statistical values are achieved when the number of contact lenses in the batch or population of contact lenses is sufficient to provide a meaningful standard error. In certain situations, a batch of contact lenses refers to at least 10 contact lenses, at least 100 contact lenses, at least 1000 contact lenses, or more.

Generally, a polymerizable composition as provided herein contains from about 0.1 weight percent to about 5 weight percent of an allyloxy alcohol. Preferably, a polymerizable composition of the invention contains from about 0.5 weight percent to about 3 weight percent of an allyloxy alcohol. That is to say, preferably, a polymerizable composition may contain any one of the following exemplary weight percentages of an allyloxy alcohol such as allyloxyethanol: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3% by weight, among others.

Free Radical Initiator

In addition to the above, the present precursor composition typically comprises one or more initiator compounds, i.e., a compound capable of initiating polymerization of a precursor composition. Preferred are thermal initiators, i.e., initiators having a “kick-off” temperature. By selecting a thermal initiator with a higher kick-off temperature, and using a relatively small amount of the initiator, it is possible to reduce the ionoflux of the present lenses, which may thereby impact the amount of removable material that is removed or extracted in the extracting step.

For instance, one exemplary thermal initiator that may be employed is VAZO.RTM.-64, which corresponds to 2,2′-azobisisobutyronitrile (AIBN), available from DuPont (Wilmington, Del.). All of the VAZO.RTM. thermal initiators described herein are available from DuPont (Wilmington, Del.), and are suitable for use in the compositions provided herein. VAZO.RTM. thermal initiators are substituted azonitrile compounds that thermally decompose to generate two free radicals per molecule. The half life in solution of VAZO.RTM.-64 at 64.degree. C. is ten hours. The grade number for each of the VAZO.RTM. initiators, e.g., “64″ in the preceding example, corresponds to the Celsius temperature at which the half-life in solution is 10 hours.

Other VAZO.RTM. initiators suitable for use in the compositions provided herein include 2,2′-azobis(2,4-dimethylpentanenitrile) (VAZO.RTM.-52), 2,2′-azobis(2-methylpropanenitrile), VAZO.RTM.67, and azo-bis-isobutyronitrile (VAZO.RTM.-88). VAZO.RTM.-52 possesses a kick-off temperature of about 50.degree. C., while VAZO.RTM.-88) has a kick-off temperature of about 90.degree. C. Additional thermal initiators suitable for use in a polymerizable composition include nitriles such as 1,1′-azobis(cyclohexanecarbonitrile) and 2,2′-azobis(2-methylpropionitrile), as well as other types of initiators such as those available from SigmaAldrich.

Ophthalmically compatible silicone hydrogel contact lenses can be obtained from precursor compositions that comprise from about 0.05 to about 1.0 weight percent, or preferably from about 0.07 weight percent to about 0.7 weight percent of a free radical initiator such as one of the VAZO.RTM. initiators described above. Specifically, a precursor composition as described herein preferably contains about 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, or 0.7 weight percent of a free radical initiator.

Additional Components of Silicone Hydrogel Contact Lens Precursor Compositions

The lens precursor compositions of the invention may also include additional components, e.g., an ultraviolet (UV) absorber, or UV radiation or energy absorber, and/or tinting agent.

A UV absorber may be, e.g., a strong UV absorber that exhibits relatively high absorption values in the UV-A range of about 320-380 nanometers, but is relatively transparent above about 380 nm. Examples include photopolymerizable hydroxybenzophenones and photopolymerizable benzotriazoles, such as 2-hydroxy-4-acryloyloxyethoxy benzophenone, commercially available as CYASORB.RTM. UV416 from Cytec Industries, 2-hydroxy-4-(2 hydroxy-3-methacrylyloxy) propoxybenzophenone, and photopolymerizable benzotriazoles, commercially available as NORBLOC.RTM. 7966 from Noramco. Other photopolymerizable UV absorbers suitable for use in the invention include polymerizable, ethylenically unsaturated triazines, salicylates, aryl-substituted acrylates, and mixtures thereof. Generally speaking, a UV absorber, if present, is provided in an amount corresponding to about 0.5 weight percent of the precursor composition to about 1.5 weight percent of the composition. Particularly preferred are compositions which include from about 0.6 percent to about 1.0 percent by weight UV absorber. Illustrative compositions may contain, e.g., about 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3, 1.4%, or about 1.5% by weight UV absorber.

The precursor compositions of the invention may also include a tinting agent, although both tinted and clear lens products are contemplated. Preferably, the tinting agent is a reactive dye or pigment effective to provide color to the resulting lens product.

Reactive dyes are those that bond to the silicone hydrogel lens material and do not bleed. Exemplary tinting agents include the following: benzene sulfonic acid, 4-(4,5-dihydro-4-((2-methoxy-5-methyl-4-((2-(sulfooxy)ethyl)sulfonyl)phen- yl)azo-3-methyl-5-oxo-1H-pyrazol-1-yl); [2-naphthalenesulfonic acid, 7-(acetylamino)-4-hydroxyl-3-((4-((sulfooxyethyl)sulfonyl)phenyl)azo)-]; [5-((4,6-dichloro-1,3,5-triazin-2-yl)amino-4-hydroxy-3-((1-sulfo-2-naphth- alenyl)azo-2,7-naphthalene-disulfonic acid, trisodium salt]; [copper, 29H, 31H-phthalocyaninato(2-)-N.sub.29, N.sub.30, N.sub.31, N.sub.32)-, sulfo((4((2-sulfooxy)ethyl)sulfonyl)phenyl)amino)sulfonyl derivative]; and [2,7-naphthalenesulfonic acid, 4-amino-5-hydroxy-3,6-bis((4-((2-(sulfooxy)ethyl)sulfonyl)phenyl)azo)-tet- rasodium salt].

Particularly preferred tinting agents for use in the present invention are phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green, chromic-alumina-cobaltous oxide, chromium oxides, and various iron oxides for red, yellow, brown and black colors. Generally, if employed, a tinting agent will comprise from about 0.05 to about 0.5 percent by weight of the composition, or preferably, from about 0.07 to about 0.3 percent by weight of the composition. Illustrative weight percentages of a tinting agent, e.g., a phthalocyanine pigment, include the following: 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, and the like. Opaquing agents such as titanium dioxide may also be incorporated. For certain applications, a mixture of colors may be employed for better simulation of natural iris appearance.

A representative precursor composition comprises, i.e., is produced by combining, from about 30 to 40 percent by weight .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly (trifluoropropylmethylsiloxane)-poly (.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), from about 40 to 50 percent by weight N-vinyl-N-methylacetamide, from about 10 to 25 percent by weight methylmethacrylate, and less than about 5% by weight combined of ethylene glycol dimethacrylate, allyloxy alcohol, 2-hydroxy-4-acryloyloxyethoxy benzophenone, phthalocyanine blue, and 2,2′-azobisisobutyronitrile.

An exemplary precursor composition is provided in Example 1. In a particularly preferred embodiment, a polymerizable composition may comprise, consist essentially of, or consist entirely of the following amounts, in weight percent, of each of the following components: about 34 percent by weight .alpha.-.omega.-bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly (trifluoropropylmethylsiloxane)-poly (.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane), about 46 percent by weight N-vinyl-N-methylacetamide, about 17 percent by weight methylmethacrylate, about 0.5 percent by weight ethylene glycol dimethacrylate, about 1 percent by weight allyloxy alcohol, about 0.9 percent by weight 2-hydroxy-4-acryloyloxyethoxy benzophenone, about 0.1 percent by weight phthalocyanine blue, and about 0.3 percent by weight 2,2′-azobisisobutyronitrile.

Certain embodiments of the present precursor compositions include polymerizable silicone hydrogel contact lens precursor compositions provided in non-polar resin contact lens molds. Other embodiments include such compositions in storage containers, such as bottles and the like, or in dispensing devices, such as manual or automated pipetting devices.

Method of Forming a Silicone Hydrogel Contact Lens

Generally, in producing a silicone hydrogel contact lens, components of a silicone hydrogel contact lens precursor composition are each weighed and then combined. The resulting precursor composition is then typically mixed, e.g., using magnetic or mechanical mixing, and optionally filtered to remove particulates.

The lenses of the invention may be produced, e.g., as illustrated in FIG. 1.

FIG. 1 is a block diagram illustrating a method for producing a silicone hydrogel contact lens. In particular, FIG. 1 illustrates a method of cast molding a silicone hydrogel contact lens. Cast molded contact lenses can be produced per se in a form suitable for direct placement on an eye of a person, without requiring further machining to modify the lens to make the lens suitable for use on an eye. The silicone hydrogel contact lenses of the present invention, produced using a cast molding procedure such as the procedure illustrated in FIG. 1, are considered herein as “cast molded silicone hydrogel contact lenses”. The present lenses are understood to be “fully molded silicone hydrogel contact lenses” if no machining is used to alter the lens design after delensing the lens product from a mold member.

Illustrative methods for producing contact lenses, such as silicone hydrogel contact lenses, are described in at least the following: U.S. Pat. Nos. 4,121,896; 4,495,313; 4,565,348; 4,640,489; 4,889,664; 4,985,186; 5,039,459; 5,080,839; 5,094,609; 5,260,000; 5,607,518; 5,760,100; 5,850,107; 5,935,492; 6,099,852; 6,367,929; 6,822,016; 6,867,245; 6,869,549; 6,939,487; and U.S. Patent Publication Nos. 20030125498; 20050154080; and 20050191335.

In turning back to FIG. 1, the process outlined in the block diagram will now be briefly described. The illustrated method includes a step 102 of placing a polymerizable silicone hydrogel lens precursor composition (202, as shown in FIG. 2) on or in a contact lens mold member. The polymerizable silicone hydrogel lens precursor composition refers to a pre-polymerized or pre-cured composition suitable for polymerization. As used herein, the present polymerizable composition may also be referred to as a “monomer mix” or “reaction mixture”. Preferably, the polymerizable composition or lens precursor composition is not polymerized to any significant extent before curing or polymerization of the composition. However, in certain instances, a polymerizable composition or lens precursor composition may be partially polymerized before undergoing curing.

The present lens precursor compositions can be provided in containers, dispensing devices, or contact lens molds prior to a curing or polymerization procedure.

Referring back to FIG. 1, step 102, the lens precursor composition is placed on a lens-forming surface of a female contact lens mold member. The female contact lens mold member generally refers to a first contact lens mold member or an anterior contact lens mold member. For example, the female contact lens mold member has a lens-forming surface that defines the anterior or front surface of a contact lens produced from the contact lens mold.

The first contact lens mold member is placed in contact with a second contact lens mold member to form a contact lens mold having a contact lens shaped cavity. Therefore, the method illustrated in FIG. 1 includes a step 104 of closing a contact lens mold by placing two contact lens mold members in contact one another to form a contact lens shaped cavity. The polymerizable silicone hydrogel lens precursor composition 202 is located in the contact lens shaped cavity. The second contact lens mold member refers to be a male contact lens mold member or a posterior contact lens mold member. For example, the second contact lens mold member includes a lens-forming surface that defines the posterior surface of a contact lens produced in the contact lens mold.

As used herein, a “non-polar resin contact lens mold” or “hydrophobic resin contact lens mold” refers to a contact lens mold that is formed or produced from a non-polar or hydrophobic resin. Thus, a non-polar resin based contact lens mold can comprise a non-polar or hydrophobic resin. For example, such contact lens molds can comprise one or more polyolefins, or can be formed from a polyolefin resin material. Examples of non-polar resin contact lens molds used in the context of the present application include polyethylene contact lens molds, polypropylene contact lens molds, and polystyrene contact lens molds. Non-polar resin based contact lens molds typically have hydrophobic surfaces. For example, a non-polar resin mold or a hydrophobic resin mold may have a static contact angle of about 90 degrees or more, as determined using the captive bubble method. With such contact angles, conventional silicone hydrogel contact lenses produced in such molds have clinically unacceptable surface wettabilities.

The method further includes curing 106 the polymerizable silicone hydrogel lens precursor composition to form a pre-extracted polymerized silicone hydrogel contact lens product 204, as shown in FIG. 2. During curing, the lens forming components of the polymerizable silicone hydrogel lens precursor composition polymerize to form a polymerized lens product. Thus, curing may also be understood to be a polymerizing step. The curing 106 may include exposing the polymerizable lens precursor composition to radiation, such as heat, or any other means effective to polymerize the components of the lens precursor composition. For example, the curing 106 may include exposing the polymerizable lens precursor composition to polymerizing amounts of heat or ultraviolet (UV) light, among other things. Curing may optionally be carried out in an oxygen-free environment. For example, curing may be carried out under an inert atmosphere, e.g., under nitrogen, argon, or other inert gases. In one particular embodiment, curing comprises heating a polymerizable composition as provided herein to a temperature greater than about 55.degree. C.

The pre-extracted polymerized silicone hydrogel contact lens product 204 refers to a polymerized product prior to undergoing an extraction procedure that removes substantially all of the removable/extractable component(s) from the polymerized product. Pre-extracted polymerized silicone hydrogel contact lens products can be provided on or in contact lens molds, extraction trays, or other devices prior to being contacted by an extraction composition. For example, a pre-extracted polymerized silicone hydrogel contact lens product may be provided in a lens shaped cavity of a contact lens mold after a curing procedure, may be provided on or in one contact lens mold member after demolding of the contact lens mold, or may be provided on or in an extraction tray or other device after a delensing procedure and prior to an extraction procedure. The pre-extracted polymerized silicone hydrogel contact lens product includes a lens forming component, such as a silicon-containing polymeric network or matrix in the shape of a lens, and a removable component that can be removed from the lens forming component. The removable component includes unreacted monomers, oligomers, partially reacted monomers, or other agents which have not become covalently attached or otherwise immobilized relative to the lens-forming component. The removable component may also include one or more additives, including organic additives, including diluents, that can be extracted from the polymerized lens product during an extraction procedure, as discussed previously. Thus, materials that may comprise the removable component include linear uncross-linked, cross-linked, and or branched polymers of extractable materials that are not cross-linked to or otherwise immobilized relative to the polymer backbone, network, or matrix of the lens body.

In addition, the removable component can include other materials, such as volatile materials, that may be passively or actively removed from the pre-extracted polymerized silicone hydrogel contact lens product prior to extraction. For example, a portion of the removable component may evaporate between the demolding step and the extraction step.

After curing the polymerizable lens precursor compositions, demolding 108 of the contact lens mold is carried out. Demolding refers to the process of separating two mold members, such as male and female mold members, of a mold containing a pre-extracted polymerized contact lens product or polymerized device. The pre-extracted polymerized silicone hydrogel contact lens product is located on one of the demolded mold members. For example, the polymerized silicone hydrogel contact lens product may be located on the male mold member or the female mold member.

The pre-extracted polymerized silicone hydrogel contact lens product 204 is then separated from the contact lens mold member upon which it is located during delensing step 110, as shown in FIG. 1. The pre-extracted polymerized contact lens product can be delensed from the male mold member or the female mold member, depending on which mold member the polymerized contact lens product remains adhered during the demolding of the contact lens mold.

After delensing the pre-extracted silicone hydrogel contact lens products, the method includes extracting 112 extractable materials from the pre-extracted silicone hydrogel contact lens product. The extraction step 112 results in an extracted silicone hydrogel contact lens product 206, as shown in FIG. 2. Extraction step 112 refers to a procedure in which a pre-extracted polymerized silicone hydrogel contact lens product is contacted with one or more extraction compositions, and may involve a single extraction step or several sequential extractions. For example, a polymerized silicone hydrogel contact lens product or a batch of polymerized silicone hydrogel contact lens products is contacted with one or more volumes of a liquid extraction medium or liquid extraction media. The extraction media typically includes one or more solvents. For example, the extraction media include ethanol, methanol, propanol, and other alcohols. Extraction media can also include mixtures of alcohols and water, such as a mixture of 50% ethanol and 50% deionized water, or a mixture of 70% ethanol and 30% deionized water, or a mixture of 90% ethanol and 10% deionized water. Alternatively, the extraction media can be substantially or entirely alcohol free, and may include one or more agents facilitating removal of hydrophobic unreacted components from a polymerized silicone hydrogel lens product. For example, the extraction media can comprise, consist essentially of, or consist entirely of water, buffer solutions, and the like. The extraction 112 can be conducted at various temperatures, including room temperature. For example, extraction can occur at room temperature (e.g., about 20.degree. C.), or it can occur at an elevated temperature (e.g., from about 25.degree. C. to about 100.degree. C.). In addition, in certain embodiments, the extraction step 112 may include contacting the lens products with a mixture of alcohol and water, which may, in certain instances, comprise the last step of a multi-step extraction procedure.

After extracting the pre-extracted polymerized silicone hydrogel contact lens products to provide an extracted polymerized silicone hydrogel contact lens product, the method includes hydrating 114 the extracted polymerized silicone hydrogel contact lens products. The hydrating step 114 may, for example, include contacting an extracted polymerized silicone hydrogel contact lens product or one or more batches of such products with water or an aqueous solution to form a hydrated silicone hydrogel contact lens 208, as shown in FIG. 2. As an example, the extracted polymerized silicone hydrogel contact lens product may be hydrated by placement in two or more separate volumes of water, including deionized water. In certain embodiments, the hydrating step 114 is combined with the extraction step 112 such that both steps are performed at a single station in a contact lens production line. The hydration step 114 may be performed in a container at room temperature, or at an elevated temperature, and if desired, at an elevated pressure. For example, hydration can occur in water at a temperature of about 120.degree. C. (e.g., 121.degree. C.) and at a pressure of 103 kPa (15 psi).

Thus, as evident from the above, the pre-extracted polymerized silicone hydrogel contact lens products and the extracted polymerized silicone hydrogel contact lens products are considered to be water swellable products or elements, and the hydrated silicone hydrogel contact lens is considered to be a product or element that is swollen with water. As used herein, a silicone hydrogel contact lens refers to a silicone hydrogel element that has undergone a hydration step. Thus, a silicone hydrogel contact lens may be a fully hydrated silicone hydrogel contact lens, a partially hydrated silicone hydrogel contact lens, or a dehydrated silicone hydrogel contact lens. A dehydrated silicone hydrogel contact lens refers to a contact lens that has undergone a hydration procedure and has subsequently been dehydrated to remove water from the lens.

After hydrating the extracted silicone hydrogel contact lens product to produce a silicone hydrogel contact lens, the method includes a step 116 of packaging the silicone hydrogel contact lens 208. For example, the silicone hydrogel contact lens 208 can be placed in a blister pack or other suitable container that includes a volume of a liquid, such as a saline solution, including buffered saline solutions. Examples of liquids suitable for the present lenses include phosphate buffered saline and borate buffered saline. The blister pack or container is then sealed, and subsequently sterilized, as shown at step 118. For example, the packaged silicone hydrogel contact lens may be exposed to sterilizing amounts of radiation, including heat, such as by autoclaving, gamma radiation, e-beam radiation, or ultraviolet radiation.

Properties of Silicone Hydrogel Lenses

As discussed above, the compositions and methods provided herein provide ophthalmically compatible silicone hydrogel contact lenses. A pre-extracted polymerized silicone hydrogel lens product is extracted and hydrated to form a silicone hydrogel contact lens having an ophthalmically acceptable surface wettability. The present lenses have an oxygen permeability, a surface wettability, a modulus, a water content, ionoflux, a design, and combinations thereof, which permit the present lenses to be comfortably worn on a patient’s eye for extended periods of time, such as for at least a day, at least a week, at least two weeks, or about a month without requiring removal of the lens from the eye.

As used herein, an “ophthalmically compatible silicone hydrogel contact lens” refers to a silicone hydrogel contact lens that can be worn on a person’s eye without the person experiencing or reporting substantial discomfort, including ocular irritation and the like. Ophthalmically compatible silicone hydrogel contact lenses have ophthalmically acceptable surface wettabilities, and typically do not cause or are not associated with significant corneal swelling, corneal dehydration (“dry eye”), superior-epithelial arcuate lesions (“SEALs”), or other significant discomfort. A silicone hydrogel contact lens having an ophthalmically acceptable surface wettability refers to a silicone hydrogel contact lens that does not adversely affect the tear film of a lens wearer’s eye to a degree that results in the lens wearer experiencing or reporting discomfort associated with placing or wearing the silicone hydrogel contact lens on an eye. Ophthalmically compatible silicone hydrogel contact lenses meet clinical acceptability requirements for daily wear or extended wear contact lenses.

The present silicone hydrogel contact lenses comprise lens bodies that have surfaces, such as an anterior surface and a posterior surface, with ophthalmically acceptable surface wettabilities (OASW). Wettability refers to the hydrophilicity of one or more surfaces of a contact lens. In one measure, a surface of a lens may be considered wettable, or may be considered to possess an ophthalmically acceptable wettability, if the lens receives a score of 3 or above in a wettability assay conducted as follows. A contact lens is dipped into distilled water, removed from the water, and the length of time that it takes for the water film to recede from the lens surface is determined (e.g., water break up time (water BUT, or WBUT)). The assay provides grades for lenses on a linear scale of 1-10, where a score of 10 refers to a lens in which a drop takes 20 seconds or more to recede from the lens. A silicone hydrogel contact lens having a water BUT of more than 5 seconds, such as at least 10 seconds or more desirably at least about 15 seconds, can be considered to possess an ophthalmically acceptable surface wettability, although in vitro assessment of WBUT is only one measure or indication of OASW. Alternatively, OASW can be assessed in vivo. A lens is considered to possess an OASW if the lens can be worn on the eye of a patient for at least six hours without discomfort or irritation reported by the patient.

Wettability can also be determined by measuring a contact angle on one or both lens surfaces. The contact angle can be a dynamic or static contact angle. Lower contact angles generally refer to increased wettability of a contact lens surface. For example, a wettable surface of a silicone hydrogel contact lens as provided herein may have a contact angle less than about 90 degrees. However, in certain embodiments of the present lenses, the lenses have a contact angle no greater than 80 degrees, and in further embodiments, the present silicone hydrogel contact lenses have advancing contact angles less than about 75 degrees, and even more preferably, less than about 70 degrees. In one embodiment, the lenses have advancing contact angles ranging from about 52 to about 62 degrees.

The present silicone hydrogel contact lenses comprise lens bodies having ophthalmically acceptable surface wettabilities. For example, a lens body of the present silicone hydrogel contact lenses typically possesses an anterior surface and a posterior surface, each surface having an ophthalmically acceptable surface wettability.

In one embodiment, a lens body of a silicone hydrogel contact lens comprises a silicone hydrogel material. The lens body has a dry weight no greater than 90% of the dry weight of the lens body prior to extraction. For example, a lens body of pre-extracted polymerized silicone hydrogel contact lens product may have a dry weight of X. After an extraction procedure, the lens body of the extracted polymerized silicone hydrogel contact lens product has a dry weight less than or equal to 0.9X. As discussed above, the pre-extracted polymerized silicone hydrogel contact lens product may, during the extraction step, be contacted with volumes of multiple organic solvents, followed by a hydration step to produce a silicone hydrogel contact lens. The hydrated silicone hydrogel contact lens is then dehydrated and weighed to determine the dry weight of the lens body of the silicone hydrogel contact lens.

For example, in certain methods, a pre-extracted polymerized silicone hydrogel contact lens product is delensed from a contact lens mold member and is weighed to provide the dry weight of the pre-extracted polymerized silicone hydrogel contact lens product. The pre-extracted lens product is then contacted with alcohol for about 6 hours and then is hydrated with water. The hydrated lens is then dried at about 80.degree. C. for about 1 hour, and then dried under a vacuum at about 80.degree. C. for about 2 hours. The dried lens is weighed to determine the dry weight of the lens body of the silicone hydrogel contact lens. The dry weights are then compared to determine the amount of extractable material present in the pre-extracted polymerized silicone hydrogel contact lens product. A pre-extracted polymerized lens product having an extractable component content of about 40% produces a lens body of a silicone hydrogel contact lens having a dry weight that is about 60% of the pre-extracted lens product. A pre-extracted polymerized lens product having an extractable component content of about 70% produces a lens body of a silicone hydrogel contact lens having a dry weight that is about 30% of the pre-extracted lens product, and so forth.

The amount of extractables, or the extractable component content, present in a pre-extracted polymerized silicone hydrogel contact lens product can be determined using the following equation: E=((Dry weight of the pre-extracted lens product-Dry weight of extracted and hydrated contact lens)/Dry weight of the pre-extracted lens product).times.100. E is the percentage of extractables present in the pre-extracted lens product.

For example, a pre-extracted polymerized silicone hydrogel contact lens product may have a dry weight of about 20 mg. If a silicone hydrogel contact lens obtained from that product has a dry weight of about 17 mg, that silicone hydrogel contact lens comprises a lens body having a dry weight that is 85% of the dry weight of the pre-extracted lens product. It can be understood that such a pre-extracted lens product has an extractable component content of about 15% (w/w). As another example, a pre-extracted polymerized silicone hydrogel contact lens product may have a dry weight of about 18 mg, and if the dehydrated silicone hydrogel contact lens obtained from the lens product has a dry weight of about 13 mg, the silicone hydrogel contact lens comprises a lens body having a dry weight that is about 72% of the pre-extracted lens product. Such a pre-extracted polymerized silicone hydrogel contact lens product has an extractable component content of about 28% (w/w).

In certain embodiments, the dry weight of the lens body of the silicone hydrogel contact lens (i.e., a silicone hydrogel contact lens that has undergone an extraction and hydration procedure) is greater than 70% of the dry weight of the lens body prior to extraction. For example, the dry weight of the post-extracted lens body may be from about 70% to about 90% of the dry weight of the pre-extracted lens body. Some embodiments of the present lenses comprise lens bodies having a dry weight from about 70% to about 78% of the dry weight of the pre-extracted lens body. In at least one embodiment, a silicone hydrogel contact lens has a dry weight of about 74% of the dry weight of the pre-extracted lens body.

Although the present pre-extracted polymerized silicone hydrogel contact lens products contain extractable materials, the extracted forms of the present silicone hydrogel contact lenses possess very small if not negligible amounts of extractable materials in the resulting lens bodies. In certain embodiments, the amount of extractable materials remaining in an extracted lens is from about 0.1% to about 4%, such as about 0.4% to about 2% (w/w). These additional extractable materials can be determined by contacting an extracted contact lens with an additional volume of a strong solvent, such as chloroform.

In addition, since the extractable component is present in and distributed throughout the polymerizable silicone hydrogel lens precursor composition and the pre-extracted polymerized silicone hydrogel contact lens product, the present lens products and contact lenses can be distinguished from surface treated silicone hydrogel contact lenses. Since the extractable component is extractable from the lens products and is substantially absent from the hydrated contact lens, the present lens products and contact lenses can be distinguished from silicone hydrogel contact lenses that have a polymeric wetting agent IPN.

The present silicone hydrogel contact lenses may comprise lens bodies obtained from non-polar resin contact lens molds that have substantially identical surface morphologies when examined in hydrated and dehydrated states. In addition, such hydrated lens bodies may have a surface roughness that is slightly less than the surface roughness of the dehydrated lens bodies. For example, the lens bodies of the present lenses may have surfaces that include nanometer sized peaks that are apparent when analyzing root mean square (RMS) roughness data of the lens surfaces. The lens bodies may comprise regions between such peaks that differentially swell compared to the peaks to provide a reduced roughness but a substantially similar surface morphology. For example, although the height of the peaks may be reduced as the lens body is hydrated, the shape of the peak remains substantially the same.

In addition or alternatively, embodiments of the present non-polar resin molded silicone hydrogel contact lenses may comprise lens bodies that have visually identifiable silicon-rich domains and silicon-poor domains when viewed with an electron microscope, such as a scanning electron microscope, a transmission electron microscope, or a scanning transmission electron microscope. The silicon-poor domains can be understood to be regions within the lens that are substantially or entirely free of silicon based on chemical analysis. The silicon-poor domains may be larger than such domains in surface treated silicone hydrogel contact lenses or silicone hydrogel contact lenses that comprise an IPN of a polymeric wetting agent. The sizes of the silicon-rich domains, silicon-poor domains, or both may be determined using conventional image analysis software and devices, such as image analysis systems available from Bioquant (Tennessee). The image analysis software systems can be used to outline the borders of the silicon-rich and silicon-poor domains and determine cross-sectional areas, diameters, volumes, and the like of the domains. In certain embodiments, the silicon-poor domains have cross-sectional areas that are at least 50%, at least 60%, at least 70%, at least 80%, or at least 90% greater than silicon-poor domains of other silicone hydrogel contact lenses.

Typically, the present lens bodies are free of a surface treatment that provides an ophthalmically acceptable surface wettability. In other words, a lens body of the present silicone hydrogel contact lenses is, in one embodiment, an un-surface treated lens body. In other words, the lens body is produced without surface treating the lens body to provide an ophthalmically acceptable surface wettability. For example, illustrative lens bodies do not include a plasma treatment or an additional coating provided to make the surface of the lens body more ophthalmically acceptable. While the present lenses have ophthalmically acceptable surface wettabilities, some embodiments may include surface treatments, if desired.

Certain embodiments of the present lenses comprise lens bodies that are cast molded elements obtained from a non-polar resin contact lens mold. A polymerized silicone hydrogel contact lens product refers to a product that was polymerized or cured in a non-polar resin contact lens mold. Or, stated another way, the polymerized silicone hydrogel contact lens product is produced in a non-polar resin contact lens mold. As discussed herein, such contact lens molds are molds that are produced using or are based on non-polar or hydrophobic resin materials. Such materials typically have relatively large contact angles on their lens forming surfaces.

The present lenses may comprise hydrated lens bodies that have an advancing contact angle on an anterior surface, a posterior surface, or anterior and posterior surface less than 90 degrees. Typically, the lens bodies have a lens surface advancing contact angle less than 75 degrees, for example, the lens bodies have a lens surface advancing contact angle of about one of the following, in degrees: 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, or 50. The lens bodies may also have a lens surface receding contact angle less than about 75 degrees. For example, the lens body may have a lens surface receding contact angle of about one of the following, in degrees: 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, or 40. In one or more embodiments, the lens body possesses a receding contact angle from about 40 to about 60 degrees.

The hysteresis, that is the difference between the advancing contact angle and the receding contact angle, is typically from about 5 degrees to about 25 degrees. However, in preferred embodiments, the hysteresis ranges from about 5 to about 15 degrees, although in certain instances, the lenses may possess a hysteresis greater than about 25 degrees and still be clinically acceptable.

The advancing contact angle can be determined using routine methods known to persons of ordinary skill in the art. For example, the advancing contact angles and receding contact angles of the contact lenses can be measured using a conventional drop shape method, such as the sessile drop method or captive bubble method. Advancing and receding water contact angles of silicone hydrogel contact lenses can be determined using a Kruss DSA 100 instrument (Kruss GmbH, Hamburg), and as described in D. A. Brandreth: “Dynamic contact angles and contact angle hysteresis”, Journal of Colloid and Interface Science, vol. 62, 1977, pp. 205-212 and R. Knapikowski, M. Kudra: “Kontaktwinkelmessungen nach dem Wilhelmy-Prinzip-Ein statistischer Ansatz zur Fehierbeurteilung”, Chem. Technik, vol. 45, 1993, pp. 179-185, and U.S. Pat. No. 6,436,481.

As an example, the advancing contact angle and receding contact angle can be determined using a captive bubble method using phosphate buffered saline (PBS; pH=7.2). The lens is flattened onto a quartz surface and rehydrated with PBS for 10 minutes before testing. An air bubble is placed onto a lens surface using an automated syringe system. The size of the air bubble can be increased and decreased to obtain the receding angle (the plateau obtained when increasing the bubble size) and the advancing angle (the plateau obtained when decreasing the bubble size).

The present lenses may, in addition or alternatively, comprise lens bodies that exhibit a water break up time (BUT) greater than 5 seconds. For example, embodiments of the present lenses comprising lens bodies with a water BUT of at least 15 seconds, such as 20 seconds or more, can have ophthalmically acceptable surface wettabilities.

Generally, the present lenses comprise lens bodies having moduli less than 1.6 MPa. Typically, the lenses are characterized by a modulus ranging from about 0.5 to about 1.5, preferably, from about 0.6 to about 1.2 mPa. In one or more embodiments, the lenses possess a moduli ranging from about 0.8 to about 1.0 MPa. For example, the lens body may have a modulus of about 1.2 MPa, 1.1 MPa, 1.0 MPa, 0.9 MPa, 0.8 MPa, about 0.7 MPa, about 0.6 MPa, or about 0.5 MPa. The modulus of the lens body is selected to provide a comfortable lens when placed on an eye and to accommodate handling of the lens by the lens wearer.

The modulus of a lens body can be determined using routine methods known to persons of ordinary skill in the art. For example, pieces of a contact lens having about 4 mm width can be cut out from a central part of lens and tensile modulus (unit; MPa) can be determined from an initial slope of a stress-strain curve obtained by tensile test at the rate of 10 mm/min in air at a humidity of at least 75% at 25.degree. C., using an Instron 3342 (Instron Corporation).

The ionoflux of the lens bodies of the present lenses is typically less than about 5.times.10.sup.-3 mm.sup.2/min. Although the lens body of some of the present lenses may have an ionoflux up to about 7.times.10.sup.-3 mm.sup.2/min, it is believed that when the ionoflux is less than about 5.times.10.sup.-3 mm.sup.2/min and when the contact lenses do not include MPC, corneal dehydration staining can be reduced. In certain embodiments, the ionoflux of the lens body ranges from about 2.times.10.sup.-3 mm.sup.2/min to about 5.times.10.sup.-3 mm.sup.2/min. For example, the ionoflux may be about 2.times.10.sup.-3 mm.sup.2/min, 2.5.times.10.sup.-3 mm.sup.2/min, 3.0.times.10.sup.-3 mm.sup.2/min, 3.5.times.10.sup.-3 mm.sup.2/min, 4.0.times.10.sup.-3 mm.sup.2/min, 4.5.times.10.sup.-3 mm.sup.2/min, or about 5.times.10.sup.-3 mm.sup.2/min. However, as described herein, the ionoflux may be greater than 7.times.10.sup.-3 mm.sup.2/min and still not cause corneal dehydration staining or other clinical problems.

The ionoflux of the lens bodies of the present lenses can be determined using routine methods known to persons of ordinary skill in the art. For example, the ionoflux of a contact lens or lens body can be measured using a technique substantially similar to the “Ionoflux Technique” described in U.S. Pat. No. 5,849,811. For example, the lens to be measured can be placed in a lens-retaining device, between male and female portions. The male and female portions include flexible sealing rings which are positioned between the lens and the respective male or female portion. After positioning the lens in the lens-retaining device, the lens-retaining device is placed in a threaded lid. The lid is screwed onto a glass tube to define a donor chamber. The donor chamber can be filled with 16 ml of 0.1 molar NaCl solution. A receiving chamber can be filled with 80 ml of deionized water. Leads of the conductivity meter are immersed in the deionized water of the receiving chamber and a stir bar is added to the receiving chamber. The receiving chamber is placed in a thermostat and the temperature is held at about 35.degree. C. Finally, the donor chamber is immersed in the receiving chamber. Measurements of conductivity can be taken every 2 minutes for about 20 minutes, starting 10 minutes after immersion of the donor chamber into the receiving chamber. The conductivity versus time data should be substantially linear.

The lens bodies of the present lenses typically have a high oxygen permeability. For example, the lens bodies have an oxygen permeability of Dk no less than 60 barrers. Embodiments of the present lenses comprise a lens body having a Dk of about 80 barrers, about 90 barrers, about 100 barrers, about 110 barrers, about 120 barrers, about 130 barrers, about 140 barrers, or more. Preferably, the lenses have a Dk of about 70 to about 110 barrers, and more preferably, from about 80 to 100 barrers.

The Dk of the present lenses can be determined using routine methods known to persons of ordinary skill in the art. For example, the Dk value can be determined using the Mocon Method, as described in U.S. Pat. No. 5,817,924. The Dk values can be determined using a commercially available instrument under the model designation of Mocon Ox-Tran System.

The present lenses also comprise lens bodies having ophthalmically acceptable water contents. For example, embodiments of the present lenses comprise lens bodies having an equilibrium water content of no less than about 30%. In certain embodiments, the lens body has an equilibrium water content ranging from about 40 to about 60% by weight. For example, the lenses provided herein may possess an equilibrium water content of about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, or even about 65%. In one or more embodiments, the lens bodies possess an equilibrium water content from about 42% to about 50% by weight.

The water content of the present lenses can be determined using routine methods known to persons of ordinary skill in the art. For example, a hydrated silicone hydrogel contact lens can be removed from an aqueous liquid, wiped to remove excess surface water, and weighed. The weighed lens can then be dried in an oven at 80 degrees C. under a vacuum, and the dried lens can then be weighed. The weight difference is determined by subtracting the weight of the dry lens from the weight of the hydrated lens. The water content (%) is the (weight difference/hydrated weight).times.100.

In addition to the specific values identified above, the present lenses may possess values in a range between any combinations of the above-identified specific values.

For example, the present contact lenses can have water contents from about 42% to about 50%, ionoflux values from about 3 to about 5 (.times.10.sup.-3 mm.sup.2/min), advancing contact angles from about 52 degrees to about 62 degrees, receding contact angles from about 40 degrees to about 60 degrees, hysteresis from about 5 degrees to about 15 degrees, Young’s moduli from about 0.6 MPa to about 1.2 MPa, elongation at least about 100%, and combinations thereof. In certain embodiments, the elongation is from about 100% to about 300%.

As discussed herein, the present lenses have features and properties that permit the lenses to be worn for prolonged periods of time. For example, the present lenses can be worn as daily wear lenses, weekly wear lenses, bi-weekly wear lenses, or monthly wear lenses. The present lenses comprise hydrated lens bodies that have surface wettabilities, moduli, ionofluxes, oxygen permeabilities, and water contents that contribute to the comfort and usability of the lenses.

The present silicone hydrogel contact lenses are vision correcting or vision enhancing contact lenses. The lenses may be spheric lenses or aspheric lenses. The lenses may be monofocal lenses or multifocal lenses, including bifocal lenses. In certain embodiments, the present lenses are rotationally stabilized lenses, such as a rotationally stabilized toric contact lens. A rotationally stabilized contact lens may be a contact lens that comprises a lens body that includes a ballast. For example, the lens body may have a prism ballast, a periballast, and/or one or more thinned superior and inferior regions.

The present lenses also comprise lens bodies that include a peripheral edge region. The peripheral edge region may include a rounded portion. For example, the peripheral edge region may comprise a rounded posterior edge surface, a rounded anterior edge surface, or a combination thereof. In certain embodiments, the peripheral edge is completely rounded from the anterior surface to the posterior surface. Therefore, it can be understood that the lens body of the present lenses may comprise a rounded peripheral edge.

The present lenses may comprise lens bodies with thickness profiles that address problems associated with existing silicone hydrogel contact lenses but that are still comfortable to the lens wearer. By varying the thicknesses of the lens bodies and the moduli of the lens bodies, the stiffness of the lens bodies can be controlled. For example, the stiffness for a region of a contact lens can be defined as the product of the Young’s modulus of the lens and the square of the thickness of the lens at a specified region. Thus, certain embodiments of the present lenses may comprise lens bodies having a center stiffness (e.g., the stiffness at the center of the lens or center of the optic zone) less than about 0.007 MPa-mm.sup.2, a lenticular junction stiffness less than about 0.03 MPa-mm.sup.2, or a combination thereof. A lenticular junction can be defined as the junction of the lenticular zone with a bevel or, for lenses without a bevel, a point about 1.2 mm from the lens edge (see U.S. Pat. No. 6,849,671). In other embodiments, the present lenses may comprise lens bodies having a center stiffness greater than 0.007 MPa-mm.sup.2, a lenticular junction stiffness greater than about 0.03 MPa-mm.sup.2, or a combination thereof.

The present silicone hydrogel contact lenses may be provided in a sealed package. For example, the present silicone hydrogel contact lenses may be provided in sealed blister packs or other similar containers suitable for delivery to lens wearers. The lenses may be stored in an aqueous solution, such as a saline solution, within the package. Some suitable solutions include phosphate buffered saline solutions and borate buffered solutions. The solutions may include a disinfecting agent if desired, or may be free of a disinfecting or preservative agent. The solutions may also include a surfactant, such as a poloxamer, and the like, if desired.

The lenses in the sealed packages are preferably sterile. For example, the lenses can be sterilized prior to sealing the package or can be sterilized in the sealed package. The sterilized lenses may be lenses that have been exposed to sterilizing amounts of radiation. For example, the lenses may be autoclaved lenses, gamma radiated lenses, ultraviolet radiation exposed lenses, and the like.

EXAMPLES

The following examples illustrate certain aspects and advantages of the present invention, however, the present invention is in no way considered to be limited to the particular embodiments described below.

The practice of the invention will employ, unless otherwise indicated, conventional techniques of polymer synthesis, hydrogel formation, and the like, which are within the skill of the art. Such techniques are fully explained in the literature. Reagents and materials are commercially available unless specifically stated to the contrary.

Methods for preparing contact lenses, e.g., silicone hydrogel contact lenses, are further described in the following: U.S. Pat. Nos. 4,121,896; 4,495,313; 4,565,348; 4,640,489; 4,889,664; 4,985,186; 5,039,459; 5,080,839; 5,094,609; 5,260,000; 5,607,518; 5,760,100; 5,850,107; 5,935,492; 6,099,852; 6,367,929; 6,822,016; 6,867,245; 6,869,549; 6,939,487; and U.S. Patent Publication Nos. 20030125498; 20050154080; and 20050191335.

In the following examples, efforts have been made to ensure accuracy with respect to numbers used (e.g., amounts, temperatures, etc.) but some experimental error and deviation should be accounted for. Unless indicated otherwise, temperature is in degrees C and pressure is at or near atmospheric pressure at sea level.

The following well-known chemicals are referred to in the examples, and may, in some instances, be referred to by their abbreviations as set forth below.

Materials and Methods

Abbreviations AE: allyloxy ethanol DI: deionized MMA: methyl methacrylate M3U: M3-U; .alpha.-.omega.-Bis(methacryloyloxyethyl iminocarboxy ethyloxypropyl)-poly(dimethylsiloxane)-poly (trifluoropropylmethylsiloxane)-poly (.omega.-methoxy-poly(ethyleneglycol)propylmethylsiloxane); dimethacryloyl silicone-containing macromer M3U used in the following examples is represented by the following formula where n is 121, m is 7.6, h is 4.4, p is 7.4, and the Mn=12,800, and the Mw=16,200 (Asahikasei Aime Co., Ltd., Japan).

##STR00004## M3U Tint: dispersion of beta Cu-phthalocyanine in M3U (% w/w). The Cu-phthalocyanine is available as Heliogen Blue K7090 from BASF. N,N-DMF: DMF; N,N-dimethylformamide NVP: 1-vinyl-2-pyrrolidone (freshly distilled under a vacuum) PDMS: polydimethylsiloxane PDMS-co-PEG: block copolymer of polydimethylsiloxane and PEG containing 75% PEG and MW of 600 (DBE712 from Gelest) PEG: polyethylene glycol PP: propylpropylene EGDMA: ethylene glycol dimethacrylate TEGDVE: triethylene glycol divinyl ether TPTMA: trimethylol propane trimethacrylate UV416: 2-(4-benzoyl-3-hydroxyphenoxy)ethyl acrylate Vazo-64: azo-bis-isobutyronitrile (V-64; thermal initiator) VMA: N-vinyl-N-methylacetamide (freshly distilled under a vacuum) VM: vinyl methacrylate Methods for Characterizing Lens Products

Advancing Contact Angle/Receding Contact Angle.

The advancing contact angle can be determined using routine methods known to persons of ordinary skill in the art. For example, the advancing contact angles and receding contact angles of the contact lenses provided herein can be measured using a conventional drop shape method, such as the sessile drop method or captive bubble method. Advancing and receding water contact angles of silicone hydrogel contact lenses can be determined using a Kruss DSA 100 instrument (Kruss GmbH, Hamburg), and as described in D. A. Brandreth: “Dynamic contact angles and contact angle hysteresis”, Journal of Colloid and Interface Science, vol. 62, 1977, pp. 205-212 and R. Knapikowski, M. Kudra: “Kontaktwinkelmessungen nach dem Wilhelmy-Prinzip-Ein statistischer Ansatz zur Fehierbeurteilung”, Chem. Technik, vol. 45, 1993, pp. 179-185, and U.S. Pat. No. 6,436,481.

As an example, the advancing contact angle and receding contact angle can be determined using a captive bubble method using phosphate buffered saline (PBS; pH=7.2). The lens is flattened onto a quartz surface and rehydrated with PBS for 10 minutes before testing. An air bubble is placed onto a lens surface using an automated syringe system. The size of the air bubble can be increased and decreased to obtain the receding angle (the plateau obtained when increasing the bubble size) and the advancing angle (the plateau obtained when decreasing the bubble size).

Modulus.

The modulus of a lens body can be determined using routine methods known to persons of ordinary skill in the art. For example, pieces of a contact lens having about 4 mm width can be cut out from a central part of a lens, and tensile modulus (unit; MPa) can be determined from an initial slope of a stress-strain curve obtained by the tensile test at the rate of 10 mm/min in air at a humidity of at least 75% at 25.degree. C., using an Instron 3342 (Instron Corporation).

Ionoflux.

The ionoflux of the lens bodies of the present lenses can be determined using routine methods known to persons of ordinary skill in the art. For example, the ionoflux of a contact lens or lens body can be measured using a technique substantially similar to the “Ionoflux Technique” described in U.S. Pat. No. 5,849,811. For example, the lens to be measured can be placed in a lens-retaining device, between male and female portions. The male and female portions include flexible sealing rings which are positioned between the lens and the respective male or female portion. After positioning the lens in the lens-retaining device, the lens-retaining device is placed in a threaded lid. The lid is screwed onto a glass tube to define a donor chamber. The donor chamber can be filled with 16 ml of 0.1 molar NaCl solution. A receiving chamber can be filled with 80 ml of deionized water. Leads of the conductivity meter are immersed in the deionized water of the receiving chamber and a stir bar is added to the receiving chamber. The receiving chamber is placed in a thermostat and the temperature is held at about 35.degree. C. Finally, the donor chamber is immersed in the receiving chamber. Measurements of conductivity can be taken every 2 minutes for about 20 minutes, starting 10 minutes after immersion of the donor chamber into the receiving chamber. The conductivity versus time data should be substantially linear.

Oxygen Permeability.

The Dk of the present lenses can be determined using routine methods known to persons of ordinary skill in the art. For example, the Dk value can be determined using the Mocon Method, as described in U.S. Pat. No. 5,817,924. The Dk values can be determined using a commercially available instrument under the model designation of Mocon Ox-Tran System.

Equilibrium Water Content.

The water content of the present lenses can be determined using routine methods known to persons of ordinary skill in the art. For example, a hydrated silicone hydrogel contact lens can be removed from an aqueous liquid, wiped to remove excess surface water, and weighed. The weighed lens can then be dried in an oven at 80 degrees C. under a vacuum, and the dried lens can then be weighed. The weight difference is determined by subtracting the weight of the dry lens from the weight of the hydrated lens. The water content (%) is the (weight difference/hydrated weight).times.100.

Example 1

Preparation of a Polymerizable Silicone Hydrogel Contact Lens Precursor Composition

A polymerizable silicone hydrogel contact lens precursor composition was prepared using the reagents and relative amounts specified below. This formulation is referred to herein as a “HM” formulation.

TABLE-US-00001 TABLE 1 Unit amount Chemical Compound (Abbrev.) (parts) Wt % (w/w) M3U 35 34.3 VMA 47 46.1 MMA 17 16.7 EGDMA 0.5 0.49 AE 1.1 1.1 UV416 0.9 0.88 TINT 0.1 0.10 (PB15; pthalocyanine blue, m3u blue) VAZO-64 0.3 0.29 Total 101.9 parts

The components in Table 1 were weighed and mixed to form a mixture. The mixture was filtered through a 0.2-20.0 micron syringe filter into a bottle, and stored for up to about 2 weeks. (This mixture is referred to herein as a polymerizable silicone hydrogel contact lens precursor composition). In Table 1, unit amounts of each compound are provided in addition to their respective weight percents (indicated on a weight by weight basis; w/w). Since the relative parts of each component add up to a total that is close to one hundred, in this instance, weight percentage and relative parts of each component are essentially the same. The ratio of MMA to VMA in the polymerizable composition is 0.36 to 1.

Example 2

Silicone Hydrogel Contact Lens Fabrication

A volume of the precursor composition from Example 1 was degassed using a repeat vacuum/nitrogen flush procedure. The degassed precursor composition was then placed into female non-polar resin mold members. The filled female mold members were then closed by placing in contact with non-polar resin male mold members at a desired pressure to achieve a tight fit. Curing was then carried out in a nitrogen batch oven at the following cycle: 30 min N.sub.2 purging at room temperature, 60 min at 65.degree. C. and 30 min at 100.degree. C. Demolding was carried out by striking the female mold member of the contact lens mold so that the male mold member was released therefrom with the polymerized silicone hydrogel contact lens product adhered to the male mold member. Delensing was carried out either by the float off method or using mechanical delensing equipment. The float off method involves soaking the male mold member containing the dry lens in a bucket of water. Typically, the lenses come off of the molds in about ten minutes. Mechanical delensing was carried out by compressing and rotating a male mold member having a polymerized silicone hydrogel contact lens product adhered thereto, directing gas between the contact lens product and the rotating male mold member, and applying a vacuum to the exposed surface of the contact lens product. The separated lenses were then loaded onto plastic trays for extraction and hydration.

Lens trays containing polymerized silicone hydrogel contact lens products were immersed in a solvent liquid, such as industrial methylated spirits (IMS) containing 95% ethanol and 5% methanol, for 45 min at room temperature. The solvent was then drained and replaced with fresh IMS, and the process repeated with IMS (3.times.), 1:1 alcohol/water (1.times.), and with DI water (3.times.).

The hydrated lenses were stored in glass vials or in blister packages containing DI water or in phosphate buffer saline at pHs from 7.1-7.5. The sealed containers were autoclaved at 121.degree. C. for 30 min. Lens measurements were taken following 24 h of autoclaving. The resulting hydrated silicone hydrogel contact lenses were weighed, and then dehydrated in an oven and weighed again to determine the dry weight of the dehydrated silicone hydrogel contact lens.

Lens properties such as contact angle, including dynamic and static contact angle, oxygen permeability, ionoflux, modulus, elongation, tensile strength, water content, and the like were determined, as described herein. Wettability of the hydrated silicone hydrogel contact lenses was also examined by measuring the water break up time for the lenses.

Ophthalmic compatibility was further examined during dispensing studies in which a contact lens was placed on an eye of a person for 1 hour, 3 hours, or 6 hours or more, and clinical assessments then made.

The silicone hydrogel contact lenses resulting from the instant formulation had ophthalmically acceptable surface wettabilities. These silicone hydrogel contact lenses possessed equilibrium water concentrations (EWC) of 44-47%, and were determined to possess an extractable content of about 26% (wt/wt).

The resulting hydrated contact lenses possessed the following properties:

TABLE-US-00002 TABLE 2 Property Value Equilibrium water content (EWC) 45-47% Oxygen Permeability (D.sub.k) 91 barrers Static contact angle (Captive bubble wetting angle) 36-38 degrees Dynamic contact angle (Advancing contact angle) 58 degrees Dynamic Contact Angle (Receding Contact Angle) 50 degrees Hysteresis (Advancing-Receding) 8 degrees Refractive Index 1.40 Ionflux 3-4 Modulus 0.8-1.0 MPa Tensile Strength 0.6-0.7 MPa

Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing description. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed herein, as such are presented by way of example. The intent of the foregoing detailed description, although discussing exemplary embodiments, is to be construed to cover all modifications, alternatives, and equivalents of the embodiments as may fall within the spirit and scope of the invention as defined by the additional disclosure. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

A number of publications and patents have been cited hereinabove. Each of the cited publications and patents are hereby incorporated by reference in their entireties.

1. A method for producing a contact lens having a photochromic pupillary region comprising: a) adding a first polymerizable monomer composition to the concave member of a casting mold comprising a concave member having a pupillary region and a convex member; b) adding a second polymerizable monomer composition comprising a photochromic amount of at least one photochromic material to the concave member of a), said second polymerizable monomer composition having a viscosity of at least 300 centipoise greater than the first polymerizable monomer composition; c) affixing the convex member to the concave member of the casting mold of b); d) at least essentially curing polymerizable composition in the casting mold of c); and e) removing the at least essentially cured contact lens from said casting mold.

2. The method of claim 1 further comprising at least partially curing the second polymerizable monomer composition: a) prior to adding it to the concave member of the casting mold of a); b) after adding it to the concave member of the casting mold of a); or c) a combination thereof.
Contact Lens Description
BACKGROUND OF THE INVENTION

The present invention relates to light sensitive photochromic contact lenses and methods for manufacturing. More particularly, the invention relates to contact lenses having light sensitive substances such as photochromic materials located within the central portion or pupillary region of the lens. The methods for manufacturing are applicable, in one non-limiting embodiment, to the cast molding method of producing contact lenses.

Photochromism is a phenomenon involving a light induced reversible change in color. An article containing such a material that becomes colored upon exposure to light radiation containing ultraviolet rays will revert to the original color when the influence of the ultraviolet radiation is discontinued. Sources of light radiation that contain ultraviolet rays include, for example, sunlight and the light of a mercury lamp. Discontinuation of the ultraviolet radiation can be achieved for example by storing the photochromic material or article in the dark or by removing the source of ultraviolet radiation (e.g., by means of filtering).

Photochromic contact lenses pose a unique set of challenges. The surface of the eye is a challenging environment for contact lenses containing photochromic molecules that typically experience diminished performance at temperatures above 70.degree. F. (21.degree. C.). The contact lens material, typically composed of 50% or more of water, is marginally compatible with what are typically very highly lypophilic molecules. Also, the eye is strongly shaded from the ultraviolet light required for activation of photochromic molecules by the brow and eyelashes.

Although methods for incorporating photochromic materials into contact lenses have been disclosed, a need remains for a fast reliable method of manufacturing photochromic contact lenses wherein the light sensitive substance is located within the central portion or pupillary region of the lens. Moreover there is a need for this process to be economical and readily adaptable to very automated equipment used today to manufacture contact lenses, e.g., hydrophilic cross-linked contact lenses.

DETAILED DESCRIPTION OF THE INVENTION

It has now been discovered that by novel and heretofore unrealized modifications to existing cast molding processes, in one non-limiting embodiment, contact lenses with central region or pupillary region photochromic activity can be prepared. The pupillary region of the eye is the area of the eye in which the opening of the pupil and the typically pigmented iris which serves as a diaphragm controlling the opening and closing of the pupil are located. The pupillary region of a contact lens or casting mold is defined herein as the area of the contact lens or casting mold that corresponds to the pupillary region of the eye and up to 50 percent of the area of the remaining contact lens. The portion of the contact lens beyond that corresponding to the pupillary region of the eye is referred to herein as the lens body.

In one non-limiting embodiment, the region of photochromic activity covers the pupil-only region. In another non-limiting embodiment, the region of photochromic activity covers the area corresponding to the pupil and iris region of the eye. In a further non-limiting embodiment, the region of photochromic activity covers the pupillary region defined hereinbefore. In alternate non-limiting embodiments, the extent of photochromic activity in the contact lens body is less than 50 percent of the lens body area, less than 30 percent, or is 10 percent or less. The percent area is based on the total area of the lens body excluding that which corresponds to the pupillary region of the eye.

It is noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless expressly and unequivocally limited to one referent.

For the purposes of this specification, unless otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and other parameters used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

The phrase “at least partially” preceding the terms “filling hydrating, extracting, replacing or eliminating” means that the extent of filling, hydrating, extracting, replacing or eliminating ranges from a partial to a complete amount of what could be filled, hydrated, extracted, replaced or eliminated. The phrases “at least partially curing a polymerizable composition” or “an at least partially cured polymerizable composition” refer to a polymerizable composition in which the curable or cross-linkable components are at least partially cured, crosslinked and/or reacted. In one non-limiting embodiment of the present invention, the degree of cured, crosslinked or reacted components can vary widely, e.g., from 5% to 90% of all of the possible curable, crosslinkable and/or reactable components.

The phrase “at least essentially cured” refers to a polymerizable composition in which the degree of reacted components ranges from greater than 90% to 100% of all of the possible curable, crosslinkable and/or reactable components. Determination of the degree of reacted components can be accomplished, in one non-limiting embodiment by an extraction process with a solvent, e.g., methanol, that can extract the monomers, other unreacted materials and impurities. The degree of (meth)acrylic, e.g., acrylic and methacrylic, group reaction can be determined using infrared spectroscopic methods known to those skilled in the art.

In one non-limiting embodiment, a method for producing a contact lens comprising a photochromic pupillary region comprises: a) adding a volume of a first polymerizable monomer composition comprising a first viscosity and a photochromic amount of at least one photochromic material to a concave member of a casting mold comprising a concave member having a pupillary region and a convex member, said volume being sufficient to produce a photochromic pupillary region in an at least essentially cured contact lens; b) adding a volume of a second polymerizable monomer composition comprising a viscosity at least 300 centipoises less than said first polymerizable monomer composition to the concave member of the casting mold of a), the total volume of the first and second polymerizable monomer composition being sufficient to produce an at least essentially cured contact lens; c) affixing the convex member to the concave member of the casting mold of b); and d) at least essentially curing the polymerizable composition in the casting mold of c).

In one non-limiting embodiment, the viscosity of the first polymerizable monomer is at least 500 centipoises higher than that of the second polymerizable monomer. In another non-limiting embodiment, the viscosity of the first is at least 1000 centipoises higher than that of the second polymerizable monomer. The viscosity of the first monomer relative to the amount higher it is than the viscosity of the second monomer can range between any of these values, inclusive of the aforementioned values, e.g., at least 350 centipoises higher. The viscosity of the monomers is determined by a Brookfield Viscometer.

In another non-limiting embodiment, the method for producing a contact lens comprising a photochromic pupillary region further comprises at least partially curing the first and/or second polymerizable monomer composition: a) prior to adding it to the concave member of the casting mold; b) after adding it to the concave member of the casting mold; or c) a combination thereof.

In a further non-limiting embodiment, the method for producing a contact lens comprising a photochromic pupillary region further comprises removing the at least essentially cured contact lens from the casting mold.

In a still further non-limiting embodiment, the method for producing a contact lens comprising a photochromic pupillary region further comprises: a) at least partially hydrating the at least essentially cured contact lens; b) at least partially extracting any unreacted monomer or impurities from the contact lens of a); c) at least partially replacing the residual liquid remaining from a) and b) in the contact lens with an isotonic salt solution; and d) at least partially eliminating the microbial content from the contact lens of c) and packaging it; or e) packaging the contact lens of c) and at least partially eliminating the microbial content.

In one non-limiting embodiment, polymerization of the polymerizable composition of the present invention can occur by mechanisms described in the definition of “polymerization” in Hawley’s Condensed Chemical Dictionary Thirteenth Edition, 1997, John Wiley & Sons, pages 901-902. Those mechanisms include by “addition”, in which free radicals are the initiating agents that react with the double bond of the monomer by adding to it on one side at the same time producing a new free electron on the other side or by “condensation”, involving the splitting out of water molecules by two reacting monomers.

In another non-limiting embodiment, polymerization of the polymerizable monomers can be accomplished by adding to the polymerizable monomer compositions an initiating amount of material capable of generating free radicals, such as organic peroxy compounds or azobis(organonitrile) compounds, e.g., a polymerization initiator. Methods for polymerizing monomer compositions are well known to the skilled artisan and any of those well known techniques can be used to polymerize the aforedescribed polymerizable compositions. Such polymerization methods include thermal polymerization, photopolymerization or a combination thereof.

Non-limiting examples of organic peroxy compounds, that can be used as thermal polymerization initiators include: peroxymonocarbonate esters, such as tertiarybutylperoxy isopropyl carbonate; peroxydicarbonate esters, such as di(2-ethylhexyl) peroxydicarbonate, di(secondary butyl) peroxydicarbonate and diisopropylperoxydicarbonate; diacyperoxides, such as 2,4-dichlorobenzoyl peroxide, isobutyryl peroxide, decanoyl peroxide, lauroyl peroxide, propionyl peroxide, acetyl peroxide, benzoyl peroxide and p-chlorobenzoyl peroxide; peroxyesters such as t-butylperoxy pivalate, t-butylperoxy octylate and t-butylperoxyisobutyrate; methylethylketone peroxide, and acetylcyclohexane sulfonyl peroxide. In one non-limiting embodiment the thermal initiators used are those that do not discolor the resulting polymerizate.

Non-limiting examples of azobis(organonitrile) compounds, that can be used as thermal polymerization initiators include: azobis(isobutyronitrile), azobis(2,4-dimethylvaleronitrile) or a mixture thereof.

The amount of thermal polymerization initiator used to initiate and polymerize the polymerizable monomer compositions can vary and will depend on the particular initiator used. In one non-limiting embodiment, only that amount that is required to initiate and sustain the polymerization reaction is required, e.g., an initiating amount. With respect to the peroxy compound, diisopropyl peroxydicarbonate, used in one non-limiting embodiment, the amount is typically between 0.01 and 3.0 parts of that initiator per 100 parts of the polymerizable organic composition (phm). In another non-limiting embodiment, between 0.05 and 1.0 phm is used to initiate the polymerization. The thermal cure cycle involves heating the polymerizable monomer composition in the presence of the initiator, in one non-limiting embodiment, from room temperature to 85.degree. C. to 125.degree. C. over a period of from 30 minutes to 30 hours.

In one non-limiting embodiment, photopolymerization of the polymerizable monomer compositions according to the present invention can be carried out in the presence of a photopolymerization initiator using ultraviolet light, visible light, or a combination thereof. Non-limiting examples of photopolymerization initiators include benzoin, benzoin methyl ether, benzoin isobutyl ether benzophenol, acetophenone, 4,4′-dichlorobenzophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-isopropylthixantone and 2,4,6-trimethylbenzoyldiphenylphosphine oxide. The amount of photopolymerization initiator used to initiate and polymerize the polymerizable monomer compositions can vary and will depend on the particular initiator used. Only that amount that is required to initiate and sustain the polymerization reaction is required, e.g., an initiating amount. In one non-limiting embodiment, the photopolymerization initiator is used in an amount from 0.01 percent to 5 percent by weight, based on the weight of monomer components.

In one non-limiting embodiment, the light source used for the photopolymerization is chosen from those which emit ultraviolet light. The light source can be a mercury lamp, a germicidal lamp or a xenon lamp. Visible light, e.g., sunlight, can also be used. The exposure time may differ depending upon, e.g., the wavelength and intensity of the light source and the particular photochromic article, and is typically determined empirically.

In another non-limiting embodiment, various conventional additives can be incorporated into the polymerizable monomer compositions of the present invention. Such additives can include light stabilizers, heat stabilizers, antioxidants, ultraviolet light absorbers, mold release agents, static (non-photochromic) dyes, pigments, solvents and polymerization inhibitors to promote stability during storage, and ultraviolet light absorbers (other than the photochromic compounds). Antiyellowing additives, e.g., 3-methyl-2-butenol, organo pyrocarbonates and triphenyl phosphite [CAS 101-02-0], can also be added to polymerizable monomer compositions of the present invention to enhance resistance to yellowing.

In a further non-limiting embodiment, it is also contemplated that a polymerization moderator, or a mixture thereof polymerization moderators, can be added to the polymerizable composition of the present invention to minimize the formation of distortions, such as striations, in polymerizates obtained therefrom. Non-limiting examples of polymerization moderators include: dilauryl thiodipropionate, terpinolene, 1-isopropyl-4-methyl-1,4-cyclohexadiene, 1-isopropyl-4-methyl-1,3-cyclohexadiene, 1,3-diisopropenylbenzene, alpha-methyl styrene, 2,4-diphenyl-4-methyl-1-pentene, 1,1-diphenylethylene, cis-1,2-diphenylethylene, 2,6-dimethyl-2,4,6-octatriene, 4-tert-butylpyrocatechol, 3-methyl-2-butenol or a mixture thereof.

In a still further non-limiting embodiment, the polymerization moderator can be added to the polymerizable monomer compositions in an amount from 0.01 percent to 20 percent by weight, e.g., from 0.1 percent to 10 percent by weight or from 0.3 percent to 5 percent by weight, based on the total weight of the polymerizable composition. The amount of polymerization moderator can range between any combination of these values, inclusive of the recited ranges, e.g. from 0.015 to 19.999 weight percent.

In one non-limiting embodiment, the polymerizate or contact lens obtained from polymerization of polymerizable monomer compositions are solid, flexible and transparent or optically clear so that they can be used as optical elements, e.g., optical contact lenses.

In another non-limiting embodiment, the photochromic material can be dispensed into the pupillary region of the polymerizable monomer composition in an at least partially filled contact lens mold that is filled with a sufficient amount to produce a pupillary region in an at least essentially cured contact lens, by addition, e.g., injection. This can be done after the process of at least partially curing the polymerizable monomers, during the process of at least partially curing the polymerizable monomers or a combination thereof.

In a further non-limiting embodiment, the polymerizable monomers used to cast the contact lens can be divided into at least two different casting mold additions. At least one photochromic material can be added to at least one casting mold addition to produce a polymerizable photochromic monomer composition. In one non-limiting embodiment, a predetermined amount, e.g., a volume sufficient to produce a photochromic pupillary region in an at least essentially cured contact lens, of polymerizable photochromic monomer composition, that can be at least partially polymerized, can be dispensed into the concave member of a casting mold comprising a concave member having a pupillary region and a convex member, before the addition of the polymerizable non-photochromic monomer composition, after the addition of the polymerizable non-photochromic monomer composition or by a combination thereof.

In another non-limiting embodiment, the polymerizable photochromic monomer composition can be at least partially cured after adding or dispensing it into the mold, thereby limiting the occurrence of mixing with the non-photochromic monomer which would be included to produce the remainder of the contact lens.

In the cast molding process, a contact lens is generally or typically formed between two steel, brass, or (more typically) plastic molds. The molds are designed with precise anterior and posterior surface geometry. During the molding process, in one non-limiting embodiment, monomer is dispensed into the concave member of the casting mold, followed by press-fitting the convex member, leaving the monomer sandwiched between the optical surfaces of the casting mold. Depending on the casting molds used, in one non-limiting embodiment, a gasket that sets the thickness of the polymerizate or contact lens can be used. The use of a gasket, if necessary, is included in the step of affixing the convex member of the casting mold to the concave member. The monomer can then be cured to create a lens via exposure to actinic radiation, e.g., ultraviolet light, a thermal process or a combination of the two curing processes.

After an essentially cured lens is formed, in one non-limiting embodiment, it is removed from the mold and undergoes at least a partial hydration and at least a partial extraction process. During these steps, the amount of water that a lens can absorb varies widely. In one non-limiting embodiment, the lens can absorb from 38% to 72% of its weight in water. After the hydration process, in one non-limiting embodiment, the lens can be extracted or rinsed with solvent. The type of solvent that can be used varies widely and depends on the material to be removed. In one non-limiting embodiment, it can be an organic solvent, such as methanol, or water, e.g., purified water having a minimized microbial level. The extraction process is done to remove any unreacted monomer and/or impurities. These processes can be run simultaneously, e.g., in a heated water bath, or sequentially.

After the hydration and extraction processes, in one non-limiting embodiment, the lens is immersed or contacted with an isotonic salt solution, such as physiological saline that can optionally be buffered. This step is intended, in one non-limiting embodiment, to replace the residual liquid remaining from the hydration and extraction steps with a salt solution that is tolerated by the eye. In another non-limiting embodiment, the resulting contact lens product can be sterilized in which the microbial content is at least partially eliminated and the resulting contact lens is packaged. In an alternate non-limiting embodiment, the contact lens can be packaged and the contents of the package can be sterilized, depending on the manufacturing process used.

In the process of the present invention, the mixture of monomers used to cast the contact lens, in one non-limiting embodiment, includes hydroxyethyl methacrylate, N-vinyl pyrrolidone, methacrylic acid, methyl methacrylate, styrene, alpha-methylstyrene, vinyltoluene, p-chlorostyrene, o-chlorostyrene, p-bromostyrene, o-bromostyrene, divinylbenzene, divinylbiphenyl, vinyl acetate, vinyl propionate, vinyl benzoate, ethyl(meth)acrylate, isopropyl(meth)acrylate, allyl(meth)acrylate, phenyl(meth)acrylate, benzyl (meth)acrylate, p-chlorophenyl(meth)acrylate, p-chlorobenzyl (meth)acrylate, p-bromophenyl(meth)acrylate, p-bromobenzyl (meth)acrylate, naphthyl(meth)acrylate, (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, 2-hydroxy-3-phenoxypropyl(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, glycerol di(meth)acrylate, 3-acryloyloxyglycerol monomethacrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, 2,2-bis(4-(meth) acryloyloxy(2′-hydroxypropyloxy)phenyl)propane, diisopropyl fumarate, diisopropyl maleate, dibenzyl fumarate, dibenzyl maleate, dibenzyl mesaconate, maleic anhydride, and itaconic anhydride. These monomers may be used alone or in a mixture thereof.

In one non-limiting embodiment, styrene and p-chlorostyrene can be included to improve the refractive index of the resin material obtained by curing the resin composition, resulting in a further reduction in specific gravity. In another non-limiting embodiment, a cross-linking monomer such as ethylene glycol dimethacrylate or diethylene glycol dimethacrylate or combinations thereof can be used.

In a further non-limiting embodiment, a first monomer having a viscosity at least 300 centipoise higher than the second monomer can also have a greater density than the second monomer. According to Hawley’s Condensed Chemical Dictionary Thirteenth Edition, 1997, John Wiley & Sons, pages 1038-1039, the definition of specific gravity states that the density of solids and liquids is numerically equal to the specific gravity. Photochromic material added to such a first monomer, used in the process of the present invention would result in a contact lens comprising a non-photochromic polymeric lens body and a photochromic pupillary region, located within the lens body, the photochromic pupillary region having a greater density than the non-photochromic lens body.

A photochromic amount of at least one photochromic material, in one non-limiting embodiment, can be added to the pupillary region of an at least partially filled concave member of a casting mold. This can be accomplished, in one non-limiting embodiment, by injecting the photochromic materials beneath the surface of the polymerizable monomer into the pupillary region of the concave member. The polymerizable composition can be at least partially polymerized prior to the addition of photochromic materials, during the addition of photochromic materials, after the addition of photochromic materials or by a combination thereof.

As used herein and in the claims, by “photochromic amount” is meant an amount of photochromic material that is at least sufficient to produce a photochromic effect discernible to the naked eye upon activation. The particular amount used depends often upon the thickness of the contact lens, size of the pupillary region and the intensity of color desired upon irradiation thereof. Typically, the more photochromic material incorporated, the greater the color intensity is up to a certain limit. There is a point after which the addition of any more material will not have a noticeable effect.

The amount of photochromic material incorporated into the polymerizable composition can vary widely. In one non-limiting embodiment, the amount ranges from 0.01 to 40 weight percent based on the weight of the polymerizable composition. For example, the concentration of photochromic material can range from 0.05 to 30 weight percent, or from 0.1 to 20 weight percent or from 0.2 to 15 weight percent, e.g., from 7 to 14 weight percent, based on the weight of the polymerizable composition. The concentration of photochromic material can range between any combination of these values, inclusive of the recited ranges, e.g., from 0.05 to 39.95 weight percent.

The photochromic materials used in the process of the present invention may be used alone or in combination with one or more other appropriate and complementary photochromic materials, e.g., organic photochromic compounds having at least one activated absorption maxima within the range of 400 and 700 nanometers, and which color when activated to an appropriate hue. Further discussion of neutral colors and ways to describe colors can be found in U.S. Pat. No. 5,645,767, column 12, line 66 to column 13, line 19.

In one non-limiting embodiment, polymerizable photochromic materials, such as polymerizable naphthoxazines disclosed in U.S. Pat. No. 5,166,345 at column 3, line 36 to column 14, line 3; polymerizable spirobenzopyrans disclosed in U.S. Pat. No. 5,236,958 at column 1, line 45 to column 6, line 65; polymerizable spirobenzopyrans and spirobenzothiopyrans disclosed in U.S. Pat. No. 5,252,742 at column 1, line 45 to column 6, line 65; polymerizable fulgides disclosed in U.S. Pat. No. 5,359,085 at column 5, line 25 to column 19, line 55; polymerizable naphthacenediones disclosed in U.S. Pat. No. 5,488,119 at column 1, line 29 to column 7, line 65; polymerizable spirooxazines disclosed in U.S. Pat. No. 5,821,287 at column 3, line 5 to column 11, line 39; polymerizable polyalkoxylated naphthopyrans disclosed in U.S. Pat. No. 6,113,814 at column 2, line 23 to column 23, line 29; and the polymerizable photochromic compounds disclosed in WO97/05213 and application Ser. No. 09/828,260 filed Apr. 6, 2001 can be used.

In a further non-limiting embodiment, the photochromic materials can include the following classes of materials: chromenes, e.g., naphthopyrans, benzopyrans, indenonaphthopyrans and phenanthropyrans; spiropyrans, e.g., spiro(benzindoline)naphthopyrans, spiro(indoline)benzopyrans, spiro(indoline)naphthopyrans, spiro(indoline)quinopyrans and spiro(indoline)pyrans; oxazines, e.g., spiro(indoline)naphthoxazines, spiro(indoline)pyridobenzoxazines, spiro(benzindoline)pyridobenzoxazines, spiro(benzindoline)naphthoxazines and spiro(indoline)benzoxazines; mercury dithizonates, fulgides, fulgimides and mixtures of such photochromic compounds. Such photochromic compounds and complementary photochromic compounds are described in U.S. Pat. No. 4,931,220 at column 8, line 52 to column 22, line 40; U.S. Pat. No. 5,645,767 at column 1, line 10 to column 12, line 57; U.S. Pat. No. 5,658,501 at column 1, line 64 to column 13, line 17; U.S. Pat. No. 6,153,126 at column 2, line 18 to column 8, line 60; U.S. Pat. No. 6,296,785 at column 2, line 47 to column 31, line 5; U.S. Pat. No. 6,348,604 at column 3, line 26 to column 17, line 15; and U.S. Pat. No. 6,353,102 at column 1, line 62 to column 11, line 64. Spiro(indoline)pyrans are also described in the text, Techniques in Chemistry, Volume III, “Photochromism”, Chapter 3, Glenn H. Brown, Editor, John Wiley and Sons, Inc., New York, 1971.

In another non-limiting embodiment, other photochromic materials, that can be used include organo-metal dithiozonates, i.e., (arylazo)-thioformic arylhydrazidates, e.g., mercury dithizonates which are described in, for example, U.S. Pat. No. 3,361,706 at column 2, line 27 to column 8, line 43; and fulgides and fulgimides, e.g., the 3-furyl and 3-thienyl fulgides and fulgimides, which are described in U.S. Pat. No. 4,931,220 at column 1, line 39 through column 22, line 41.

The disclosures relating to such photochromic compounds in the aforedescribed patents, indicated by column and line number, are incorporated herein by reference.

In one non-limiting embodiment, the process of the present invention utilizes a means to carry out separate additions to the concave member of the casting mold. For example, two high precision valves and controllers can be included in the standard mold casting equipment for addition of the polymerizable monomer and the photochromic amount of at least one photochromic material or for the addition of the two different polymerizable monomer compositions, e.g., one photochromic and the other non-photochromic. In another non-limiting embodiment, a dispensing means that adds material in a non-disruptive or non-turbulent fashion so as to avoid mixing or disturbing the material already in the mold, can be used. Such equipment is frequently used in the electronics and medical device industries. A non-limiting example of such equipment includes the 740MD-SS micro dot needle valve and Valvemate.RTM. 7000 controller available from the EFD Corporation, East Providence, R.I., 02914.

In another non-limiting embodiment, the needle valve and controller used to add the photochromic containing compositions have a high degree of precision, not only volumetrically but also positionally, e.g., when adding to the pupillary region of the at least partially filled casting mold. Positional precision will also be a function of the degree of control of the dispense tip that has been selected. The needle valve and controller adding the non-photochromic monomer, in one non-limiting embodiment, can be less precise volumetrically as this material will normally be added in excess.

In one non-limiting embodiment of the present invention, photochromic monomer can be first dispensed into the concave (female) member of the casting mold via a precision dispense tip. Although this amount will vary with lens design and correction, typically a volume on the order of 2 to 6 microliters can be dispensed. In another non-limiting embodiment, the monomer is precisely placed in the center of the concave member. The volume dispensed depends on the lens design and power but can be determined based on the volume of the central pupillary area of the finished contact lens. Allowance in the calculation needs to be made for shrinkage that occurs during polymerization and swelling that occurs during hydration. In a further non-limiting embodiment, the diameter of the pupillary region can vary widely depending on the contact lens design and/or focusing power of the lens. In one non-limiting embodiment, it ranges from five to fifteen millimeters (mm), from six to ten mm, e.g., 8 mm. The diameter of the pupillary region can range between any combination of these values, inclusive of the recited ranges.

In another non-limiting embodiment, the polymerizable non-photochromic monomer composition, typically 10 or more microliters, can be dispensed in excess on top of or around the polymerizable photochromic monomer composition taking care not to disturb the central pool of photochromic monomer using the aforementioned dispensing means. In one non-limiting embodiment, some mixing can occur due to, for example, simple Brownian motion. This can produce a lens that does not have a distinct boundary between clear and photochromic sections but rather a mixing or blending of these sections. In some instances this can have a desirable cosmetic effect. In one non-limiting embodiment, half of the non-pupillary region of the lens remains non-photochromic.

In one non-limiting embodiment, the degree of mixing or blending of the photochromic and non-photochromic sections can be controlled by varying the time until either or both monomer compositions is at least partially or essentially cured. If less blending is desired, in one non-limiting embodiment, rapid curing can be most effective in maintaining separate zones. Where some blending is desirable, a slower curing process can be employed. Of course it is also possible to use a combination of cure methods to achieve the desired effect.

In cases where a clear demarcation is desired between photochromic and non-photochromic zones, in one non-limiting embodiment, it can be accomplished by at least partially curing, one or both of the monomer mixtures, before addition to the concave member of the casting mold, after addition to or a combination thereof. In another non-limiting embodiment, viscosity differences can be used to limit blending of the two different monomers compositions. If the photochromic monomer composition is at least partially cured, in one non-limiting embodiment, it can be more viscous and not tend to flow as readily towards the edges during press-fitting of the convex (male) mold member. By using materials of different viscosities, it is less likely that they will blend together prior to polymerization. Also, by using as photochromic monomer materials having a higher viscosity and higher density than the non-photochromic monomers, a contact lens having a photochromic pupillary region of higher density than the non-photochromic lens body can be made. As previously mentioned, the specific gravity of a liquid is numerically equal to the density. Such information about monomers is typically provided by manufacturers in their product catalog, e.g., see the Sartomer Product Catalog.

In an alternate non-limiting embodiment, the viscosity of a monomer can be reduced by the addition of less viscous materials, such as other monomers having a lower relative viscosity or solvents. The addition of a small volume of solvent to the polymerizable monomer composition, in one non-limiting embodiment, can reduce the viscosity during pumping or dispensing. Once the monomer is dispensed into the concave member of the casting mold, in one non-limiting embodiment, the solvent could be removed in all or part, by purging with a stream of nitrogen or other inert gas, prior to a subsequent addition of photochromic material and/or more polymerizable monomer composition. In one non-limiting embodiment, a solvent can be added to the polymerizable non-photochromic monomer composition to decrease its viscosity relative to the polymerizable photochromic monomer composition. Doing so can increase the ability of the polymerizable non-photochromic monomer composition to pool to the outside of the central, more viscous, photochromic monomer in the concave member of the casting mold.

Non-limiting examples of solvents include: benzene, toluene, methyl ethyl ketone, methyl isobutyl ketone, acetone, ethanol, tetrahydrofurfuryl alcohol, propyl alcohol, propylene carbonate, N-methylpyrrolidinone, N-vinyl pyrrolidinone, N-acetyl pyrrolidinone, N-hydroxymethylpyrrolidinone, N-butyl pyrrolidinone, N-ethyl pyrrolidinone, N–(N-octyl) pyrrolidinone, N–(N-dodecyl) pyrrolidinone, 2-methoxyethyl ether, xylene, cyclohexane, 3-methyl cyclohexanone, ethyl acetate, butyl acetate, tetrahydrofuran, methanol, amyl propionate, methyl propionate, propylene glycol methyl ether, diethylene glycol monobutyl ether, dimethyl sulfoxide, dimethyl formamide, ethylene glycol, mono- and dialkyl ethers of ethylene glycol and their derivatives, which are sold as CELLOSOLVE industrial solvents by Union Carbide, and mixtures of such solvents.

In another non-limiting embodiment, in the process of affixing the convex member to the concave member of the casting mold, the less viscous non-photochromic monomer can flow more readily and result in a final lens product having a non-pupillary region that is non-photochromic. After the lens is essentially cured, it can be removed from the mold. Subsequently, the processes traditionally used in the contact lens fabrication such as hydration, extraction or rinsing, sterilization and packaging, will remain unchanged from that known in the art.

In a further non-limiting embodiment, the aforementioned methods of the present invention are used to produce the contact lenses of the present invention.

The present invention is more particularly described in the following example, which is intended as illustrative only, since numerous modifications and variations therein will be apparent to those skilled in the art.

EXAMPLE

Part A

To the concave half of a crown glass casting mold having a 6 base curvature was added 4 drops of SR 9036 (reported to be a Bisphenol A 30 ethoxylated dimethacrylate from Sartomer) and 2 drops of SR 348 monomer (reported to be a Bisphenol A 2 ethoxylated dimethacrylate from Sartomer) containing approximately 2 weight percent, based on the weight of the monomer, of a photochromic naphthopyran that exhibits a blue color when irradiated with ultraviolet light, and 0.5 weight percent, based on the weight of the monomer, of Irgacure 819 (reported to be a phosphine based initiator available from Ciba Geigy).

Part B

The concave half of the crown glass mold of Part A was fitted with a gasket of about 1 millimeter thickness and the corresponding convex half of the crown glass mold was applied with slight pressure to form a complete casting mold. The polymerizable composition in the completed casting mold was cured by exposure to ultraviolet radiation by exposing it on one pass at a speed of 5.0 feet per minute (152.4 cm per minute) on a conveyor belt, beneath two ultraviolet type “D” lamps of 10 inch (25.4 cm) length. The first lamp was maintained at a height of 2.5 inches (6.4 cm) above the conveyor and the second lamp at 6.5 inches (16.5 cm) above the conveyor. The curing system was obtained from Eye Ultraviolet system and had been inerted with nitrogen to a level of less than 100 parts per million of oxygen.

Part C

The casting mold was separated and a lens having an outside diameter of about 1 inch or 2.54 cm, a clear lens body and a colored pupillary region of about 0.44 inch or 1.11 cm was recovered. The lens was exposed to ultraviolet radiation and the pupillary region became darker and after the ultraviolet radiation was discontinued, the pupillary region became less dark.

While the present invention has been described with respect to particular embodiments of apparatus and methods, it will be appreciated that various modifications and adaptations may be made based on the present disclosure and are intended to be within the scope of the accompanying claims.