WO1992018548A1

WO1992018548A1 - Novel composition for contact lenses

Info

Publication number: WO1992018548A1
Application number: PCT/US1992/003128
Authority: WO
Inventors: Richard Y. S. Chen
Original assignee: Optical Research, Inc.
Priority date: 1991-04-18
Filing date: 1992-04-16
Publication date: 1992-10-29
Also published as: CA2108682A1

Abstract

A hydrogel copolymer for making contact lenses comprises, by weight, about 5 to about 85 percent of α-methylene-N-methylpyrrolidone or glycerdyl methacrylate and mixtures thereof from about 5 to about 35 percent of N,N-dimethylacrylamide, from about 5 to about 60 percent of a polymerizable fluoromonomer, and from about 1 to about 15 percent of a polymerizable hydrophobic non-hydrolyzable silicone monomer. An initiator and a crosslinker are usually preferably also employed.

Description

NOVEL COMPOSITION FOR CONTACT LENSES

Background ofthe Invention

This invention relates to contact lenses, and in particular to pliable or "soft" contact lens having an exceptional combination of oxygen permeability, strength, and resistance to protein and mucus deposits. There is a great need for a contact lens that has high oxygen permeability and wettability and resistance to protein and mucus deposits. These properties all contribute to an extension of the time during which a contact lens can be continuously worn by a wearer.

High oxygen permeability is needed because the pupil of the eye has no blood circulation and extracts the oxygen needed by its cells directly from the atmosphere. Wettability is essential for wearer comfort. Resistance to protein and mucus deposits from fluids that bathe the outer surface of the eye is essential since without this feature the lens pores become clogged and both visual acuity and the oxygen permeability of the lens suffer. Many types of contact lens compositions have been proposed. There are two general categories of contact lenses—rigid and hydrogel. For example, U.S. Patent Nos. 3,808,178 and 4,120,570 to Gaylord; 4,139,692 to Tana a et al; 4,686,276 to Ellis et al; 4,743,106 to Novicky et al, and 4,812,598 to Chen propose the use of various copolymer compositions including silicon in contact lenses. The lenses are reasonably permeable to oxygen but are not of hydrogel or "soft" construction.

U.S. Patent No. 4,130,706 to Plambeck, Jr. proposes a methacrylate-type fluoropolymer ("FMA") for making contact lenses. While the lenses are described as hydrophilic and oxygen permeable, it is believed that they are not wettable enough to be truly comfortable to persons wearing the lenses and are not sufficiently permeable to oxygen to be worn safely and continuously for extended periods.

U.S. Patent No. 3,940,207 to Barkdoll proposes contact lenses constructed of fluorine- containing polymers that are soft and have a low refractive index. It is believed that these contact lenses are not sufficiently oxygen permeable to be worn safely for extended periods. U.S. Patent Nos. 4,954,587 and 5,011,275 to

Mueller propose soft, extended wear contact lenses based on N,N-dimethylacrylamide ("DMA") . While the lenses have a high oxygen permeability, the use of higher amounts of the relatively soft polymer of N,N- dimethylacrylamide is limited in that the lenses could become too soft to be fabricated.

It would be highly desirable to provide a hydrogel copolymer which can be used to form an easily fabricated pliable contact lens having the combination of oxygen permeability, wettability and resistance to protein and mucus deposits.

Summaryofthe Invention

The present invention relates to a hydrogel copolymer for making contact lenses, the copolymer comprising, by weight, about 10 percent to about 85 percent of α-methylene-N-methylpyrrolidone or glycerdyl methacrylate and mixtures thereof, from about 5 to about 25 percent of N,N-dimethylacrylamide, about 5 percent to about 80 percent of a polymerizable fluoromonomer, and about 1 percent to about 15 percent of a polymerizable hydrophophic , non-hydrolyzable silicone monomer. Optionally, an initiator and a crosslinker are employed under circumstances disclosed below.

In one embodiment of the invention, the copolymer comprises, by weight, from about 10 to 85 percent α-methylene-N-methylpyrrolidone, from about 5 to about 85 percent of glycerdyl methacrylate, from about 5 to about 60 percent of a polymerizable fluoromonomer, and from about 1 to about 15 percent of a polymerizable hydrophobic non-hydrolyzable silicone monomer.

In another embodiment, the copolymer comprises, by weight, from about 40 to about 90 percent of α-methylene-N-methylpyrrolidone and from about 10 to about 60 percent of a polymerizable fluoromonomer such as fluoroacyrlates, styryl fluoro onomers and vinyl fluoromonomers.

Detailed Description of the Preferred Embodiments

The present invention will now be described more fully hereinafter. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiment set forth herein; rather, this embodiment is 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.

The present invention utilizes in various combinations, as described below α-methylene-N- methylpyrrolidone ("Q.-MMP") or glycerdyl methacrylate ("GMA") and mixtures thereof, N,N-dimethyl methacrylamide, a polymerizable fluoromonomer, a polymerizable hydrophobic, non-hydrolyzable silicone monomer, an initiator, and a crosslinker.

Preferably, the hydrogel copolymer comprises, by weight, from about 5 to about 85 percent of α- methylene-N-methylpyrrolidone or glycerdyl methacrylate and mixtures thereof, from about 10 to about 25 percent, and preferably from about 5 to about 20 percent of N,N-dimethylacrylamide, from about 5 to about 85 percent, and preferably from about 20 to about 40 percent by weight of a polymerizable fluoromonomer and from about 1 to about 15 percent, and preferably from about 2 to about 4 percent of a polymerizable hydrophobic non-hydrolyzable silicone monomer. Preferably, from about 20 to about 30 percent of α- methylene-N-methylpyrrolidone or from about 5 to about 30 percent of glycerdyl methacrylate is used. If a mixture of α-methylene-N-pyrrolidone and glyceridyl methacrylate is used, preferably from about 10 to about 85 percent of α-methylene-N-pyrrolidone and from about 5 to about 85 percent of glycerdyl methacrylate are used.

In one embodiment of the invention, from about 50 to about 90 percent of α-methylene-N- pyrrolidone can be blended with from about 10 to about 50 percent of a polymerizable fluoromonomer to form the hydrogel copolymer. In this embodiment, the hydrogel copolymer can further include, by weight, from about 10 to about 25 percent of a polymerizable hydrophilic monomer selected from the group consisting of methacrylic acid ("MA"), 2-hydroxyethylmethacrylate ("HEMA"), N-vinyl-2-pyrrolidone ("NVP") and N,N- ^■ dimethylacrylamide ("DMA") .

The polymerizable fluoromonomer useful herein can vary. An exemplary fluoromonomer is one based on a fluoroacrylate composition which includes the following fluorine-containing monomer:

where R is H or CH₃, m is an integer from 0 to 9, and n is an integer from 1 to 4. A similar monomer is disclosed in U.S. Patent No. 4,130,706 to Plambeck, Jr. , the disclosure of which is incorporated herein by reference.

Another exemplary fluoromonomer can be a fluoracrylate

where R and m are defined as above. A similar monomer is disclosed in U.S. Patent No. 3,282,905 to Fosick et al, the disclosure of which is incorporated herein by reference.

A particularly preferred composition is 2,2,2-trifluoroethyl methacrylate ("FMA") .

CH₃

I CH₂- C F

I I

0= C-0-CH₂-C- Alternatively, styryl fluoromonomers can be employed. The general formula of these monomers is

where r + s = 5 and r = 1 to 5 and s - 5 to 1. A particularly preferred styryl fluoromonomer is pentafluorostyrene.

Other examples of fluoromonomers are p-vinyl benzyl trifluoroacetate and p-vinyl benzyl hexafluoroisopropyl ether.

Alternatively, vinyl fluoromonomers can be used. They have the general formula

CH₂-CH

where t = 1 to 4 and u = 1 to 9. A particularly preferred vinyl fluoromonomer is 3 , 3 , 3 trifluorovinylpropane

CH,-CH F

I I

CH₂CH_Z-C-F Alternatively, perfluorocyclohexyl acrylates can be used having the general formula

where R - H or CH₃. A particularly preferred pefluorocyclohexyl acrylate is perfluorocyclopentene. It is noted that only α-methylene-N-methylpyrrolidone and the polymerizable fluoromonomer can be used.

The polymerizable hydrophobic non- hydrolyzable silicone monomer useful herein can vary. An exemplary silicone has the formula

where a is an integer from 1 to 5 and b is an integer from 0 to 6, A is selected from the group consisting of CPJ-CJ alkyl groups and phenyl groups, R is selected from the group consisting of a methyl group (CH₃) and hydrogen, X and Y are selected from the group consisting of C, to C₅ alkyl groups, phenyl groups and Z groups wherein Z is a group of the structure

-0-

where a and A are as defined previously, and φ is a phenyl group. In the alkanol ester co-monomers, the alkyl group contains from 1 to 20 carbon atoms. Exemplary silicon-containing monomers are disclosed in U.S. Patent Nos. 3,808,178 and 4,120,570 to Gaylord, the disclosures of which are incorporated herein by reference.

Alternatively, vinyl silicone monomers can be employed. The general formula can be represented as

where X = 1 to 6 and R₁ is selected from the class consisting of C, to C₆ alkyl groups and phenyl groups or a mixture of alkyl and phenyl groups.

Particularly preferred examples of Class (I) are

where "ø" represents a phenyl group. Particularly preferred examples of Class (II) are CH₂=CH CH, CH₂-CH CH.

CH₂CH₂Si-CH₃ CH₂CH₂-SI-φ

CH₃ CH₃

In both classes of vinyl silicone monomers, any methyl group (CH₃ group) can be replaced by a benzene ring, as the preceding examples suggest.

Generally, vinyl silicone monomers are less reactive than acrylate silicone monomers. When vinyl silicone monomers are used, cobalt-60 ("Co-60") , radiation may be used as a source of polymerization energy. Co-60 may optionally be used as a source of polymerization energy even when vinyl silicone monomers are not employed.

Exemplary non-hydrolyzable silicones include methyldi(trimethylsiloxy)silylpropylglycerol methacrylate, methylidi(trimethylsiloxy)silylpropyl- glycerolethyl methacrylate, m,p-styrlethyltrimethyl- silane, m,p-styrylethyltris(trimethylisiloxy)silane, methylacryloxypropyltris(trimethylsiloxy)silane and 4- (3-trimethylsilylpropyl)benzylstyrene sulfonate. Preferably a crosslinker is used. The crosslinker can constitute, by weight, about 0.01 percent to about 5 percent and more preferably about 0.5 percent to about 2 percent of the weight of the hydrogel copolymer. The crosslinker is preferably one of a mixture of ethyleneglycoldimethacrylate ("EGDMA") , a fluorine-containing compound, or a silicon-containing compound such as l,3-bis[(p-acryloxymethyl) phenethyl]tetramethyldisiloxane or bis(3- methacryloxypropyl)tetramethyldisiloxane.

A quantity of an initiator equal in weight to 0.05 percent to 2 about percent of the weight of the mixture of monomers is preferably added thereto, except when Co-60 is used as a source of polymerization energy. The initiator may be selected from the group consisting essentially of 2,2•-azobis(2,4- di ethylvaleronitrile) ("VAZO 52"), azobisisobutyro- nitrile ("AIBN"), benzoinmethylether ("BME") , di(sec- butyl)peroxydicarbonate ("SBC"), and isopropylperoxydicarbonate ("Ipp") • The initiator may also be any of those disclosed in the U.S. Patent No. 4,120,570, to Gaylord, i.e., acety1 peroxide, lauroyl peroxide, decanoyl peroxide, caprylyl peroxide, benzoyl peroxide, tertiary-butyl peroxypivalate, diisopropyl peroxycarbonate, tertiary-butyl peroctoate, and α,α*-azobisisobutyronitrile. VAZO 52 or AIBN may be used as an initiator when polymerization is aided by ultraviolet or thermal radiation, BME may be used as the initiator when polymerization is aided by the ultraviolet radiation, and SBC or Ipp may be used as the initiator when polymerization is aided by thermal radiation. Co-60 or another radioactive source may also be used to promote polymerization, particularly when vinyl silicone monomers or other monomers that are not highly reactive are employed. When Co-60 or another radioactive source is not used, polymerization energy is supplied in the form of thermal energy or in the form of ultraviolet radiation, as may be appropriate in view of the initiator employed. When Co-60 radiation is employed, no initiators are needed. After curing, the resulting polymer is formed in any conventional or otherwise suitable process into contact lenses. The lenses have a shore hardness (D scale) within the range of 82 to 89. Oxygen permeability in DK units (ml cm/cm² sec cmHg X 10^"10) at 35*C is within the range of 20 to 55. The contact angle is within the range of 10^•-34*, light 5 transmission is greater than 95%, refractive index is close to that of HEMA, and the coefficient of expansion is within the range of 1.1 to 1.6.

The following examples set forth representative formulas for the materials used in 10 making contact lenses according to the invention:

Example 1

The following are mixed at room temperature in a 100ml beaker:

Percent By 15 Ingredients Weiσht α-MMP¹ 9.97

FMA² 34.89

DMA³ 24.42

MDC⁴ 29.91

20 EGDMA⁵ (crosslinker) .49

Ipp⁶ (initiator) 0.03

The initiator is added to the mixture, and the mixture is poured into a test tube and polymerized by thermal polymerization (i.e., application of heat)

25 at a temperature of 30"C for approximately 10 hours.

¹ a-methylene-N-methylpyrrolidone

^2,2,2-tτifluoroethylmethacrylate available from Aldrich Chemical Company of Milwaukee, Wisconsin N,N-dimethylacrylamide available from Aldrich Chemical Company

30 ^methylacryloxypropyltris(trimethylsiloxy)silane available from Huls America, Inc. of Newark, New Jersey

^etheylenegtycoldimethacrylate available from Rohm Tech, Inc. ofMarden, Massachusetts

⁶isopropylperoxydicarbonate available from Pofyscience, Inc. of Warrington, Pennsylvania This is accomplished by placing the test tube in a hot water bath at a temperature of 30'C. The polymerized material is a colorless, solid, transparent polymer. The polymer is lathe-cut into buttons of conventional shape and size. The buttons are ground to the shape of contact lenses having respective center thicknesses of 0.1mm to 0.2mm, and then polished. The lenses are highly transparent (light transmission is greater than 95%) and have uniform optical properties. They have an oxygen permeability of 35 DK units at 35*C (normal eye temperature) , a contact angle of less than 18", and a refractive index of 1.405.

The following examples are similar to Example 1 but illustrate variations of the materials and quantities thereof employed and of the method of polymerization.

Example2

Percent By Ingredients Weight α-MMP 9.97 FMA 19.94

DMA 39.38

MDC 29.90

EGDMA .50

BME⁷ 0.02 The mixture is molded in the form of shells and polymerized by ultraviolet radiation in accordance with

U. S. Patent No. 4,812,598 to Chen, the disclosure of which is incorporated herein by reference. The shells are lathe-cut to form contact lenses in accordance therewith.

benzoinmethylether initiator available from Pofyscience, Inc. Example 3

Percent By Ingredients Weight α-MMP 64.74

MDC 9.96

FMA 24.90

BME 0.04 The mixture is molded in the form of shells and polymerized by UV polymerization in accordance with

Example 2. The shells are lathe-cut to form contact lenses in accordance therewith.

Example4 Percent By

Ingredients Weight α-MMP 10.00

FMA 30.00

DMA 29.50 MDC 30.00

EDGMA 0.50

BME 0.02

The mixture is molded in the form of shells and polymerized by UV polymerization in accordance with Example 2. The shells are lathe-cut to form contact lenses in accordance therewith.

Example5

Ingredients GMA MDC

FMA

DMA

EGDMA VAZO-52

The mixture is molded in the form of shells and polymerized by thermal polymerization in accordance with Example 1. The shells are lathe-cut to form contact lenses in accordance therewith. The lenses are highly transparent (light transmission is greater than 95%) and have uniform optical properties. They have an oxygen permeability of 46.7 DK units at 35"C (normal eye temperature) , an expansion factor of 1.39, and a water content of about 54 percent.

Example6

Percent By Ingredients Weight α-MMP 57.95 NVP⁸ 20.00

FMA 15.00

MDC 7.00

EGDMA 0.05

VAZO-52 0.02 The mixture is molded in the form^' of shells and polymerized by UV polmerization in accordance with

The lenses are highly transparent (light transmission is greater than 95%) and have uniform optical properties. They have an oxygen permeability of 47.4 DK units at 35"C, an expansion factor of 1.4, and a water content of about 65 percent.

N-vinyl-2-pyrrolidone Example7

Percent By Ingredients Weight α-MMP 75.00 FMA 24.70

EGDMA 0.30

VAZO-52 0.30

The lenses are highly transparent (light transmission is greater than 95%) and have uniform optical properties. They have an oxygen permeability of 25 DK units at 35*C, an expansion factor of 1.32, and a water content of about 54.4 percent.

-Example8

Percent By Ingredients Weight α-MMP 80.00

FMA 19.20

EGDMA 0.30

BME 0.30

The lenses are highly transparent (light transmission is greater than 95%) and have uniform optical properties. They have an oxygen permeability of 62.7 DK units at 35°C, an expansion factor of 1.69, and a water content of 77.3 percent. Example 9

Percent By Ingredients Weight α-MMP 67.95 GMA 17.00

FMA 10.00

MDC 5.00

EGDMA 0.05

VAZO-52 0.02 The mixture is molded in the form of shells and polymerized by UV polymerization in accordance with

The lenses are highly transparent (light transmission is greater than 95%) and have uniform optical properties. They have an oxygen permeability of 45.5 DK units at 35*C, an expansion factor of 1.38, and a water content of 62.5 percent.

Thus there is provided in accordance with the invention a novel and highly-effective contact lens that has an exceptional combination of oxygen permeability, wettability and resistance to protein and mucus deposits. A novel material for manufacturing the lens is also provided, and it is noted that the material may be used for other medical articles needing the combination of oxygen permeability, wettability and resistance to protein and mucus deposits.

Many modifications of the preferred embodiments of the invention disclosed above will readily occur to those skilled in the art upon consideration of this disclosure. For example, initiators other than the ones disclosed may be employed, the contact lens may be tinted or clear, the temperature and times of polymerization may vary, etc. Accordingly, the invention is not limited except by the appended claims.

Claims

That Which Is Claimed Is

1. A hydrogel copolymer useful for making pliable contact lenses, said copolymer comprising, by weight:

(a) from about 5 to about 85 percent of α-methylene-N-methylpyrrolidone or glycerdyl methacrylate and mixtures thereof;

(b) from about 5 to about 35 percent of N,N-dimethylacrylamide;

(c) from about 5 to about 60 percent of a polymerizable fluoromonomer; and

(d) from about 1 to about 15 percent of a polymerizable hydrophobic non-hydrolyzable silicone monomer.

2. A hydrogel copolymer according to Claim 1 wherein the weight of the α-methylene-N- methylpyrrolidone is about 20 to about 3Θ percent by weight.

3. A hydrogel copolymer according to Claim 1 wherein the weight of the glycerdyl methacrylate is about 5 to about 30 percent by weight.

4. A hydrogel copolymer according to Claim 1 wherein the weight of said fluoromonomer is from about 20 percent to about 40 percent by weight.

5. A hydrogel copolymer according to Claim 1 wherein the weight of said silicone manomer is from about 2 percent to about 4 percent of the weight of said copolymer.

6. A hydrogel copolymer according to Claim 1 wherein said fluoromonomer is selected from the group consisting of fluoroacrylates, styryl fluoromonomers, and vinyl fluoromonomers.

7. A hydrogel copoloy er according to Claim 1 wherein said silicone monomer is

where a is an integer from 1 to 5 and b is an integer from 0 to 6, A is selected from the group consisting of C.,-C₅ alkyl groups and phenyl groups, R is selected from the group consisting of a methyl group (CH₃) and hydrogen, X and Y are selected from the group consisting of C, to C₅ alkyl groups, phenyl groups and Z groups wherein Z is a group of the structure

where a and A are as defined previously, and φ is a phenyl group.

8. A hydrogel copolymer according to Claim 1 wherein said silicone monomer is selected from the group consisting of methyldi(trimethylsiloxy)silyl- propylglycerol methacrylate, methylidi(trimethyl¬ siloxy)silylpropylglycerolethyl methacrylate, m,p- styrlethyltri ethylsilan , m,p-styrylethyltris- (trimethylisiloxy)silane, methylacryloxypropyltris- (trimethylsiloxy)silane and 4-(3-trimethylsilylpropyl)- benzy1styrene sulfonate.

9. A hydrogel copolymer according to Claim 1 further comprising, by weight, about 0.01 to about 5 percent, of an initiator selected from the group consisting of 2,2'-azobis(2,4- dimethylvaleronitrile) , azobisisobutyronitrile, benzoinmethylether, di(sec-butyl)peroxydicarbonate, and isopropylperoxydicarbonate.

10. A hydrogel copolymer according to Claim 1 further comprising, by weight, about 0.05 to about 2 percent of a crosslinker selected from the group consisting of a silicon-containing crosslinker, a fluorine-containing crosslinker, ethyleneglycoldi- methacrylate and mixtures thereof.

11. A hydrogel copolymer useful for making pliable contact lenses, said copolymer comprising, by weight:

(a) from about 10 to about 85 percent of α-methylene-N-methylpyrrolidone;

(b) from about 5 to about 85 percent of glycerdyl methacrylate;

(c) from about 5 to about 60 percent of a polymerizable fluoromonomer; and (d) from about 1 to about 15 percent of a polymerizable hydrophobic non-hydrolyzable silicone monomer.

12. A hydrogel copolymer according to Claim 11 wherein the weight of the α-methylene-N- . methylpyrrolidone is about 20 to about 30 percent by weight.

13. A hydrogel copolymer according to Claim 11 wherein the weight of the glycerdyl methacrylate is about 5 to about 30 percent by weight.

14. A hydrogel copolymer according to Claim 11 wherein the weight of said fluoromonomer is about 20 percent to about 40 percent of the weight of said copolymer.

15. A hydrogel copolymer according to Claim 11 wherein the weight of said silicone monomer is about 2 percent to about 4 percent of the weight of said copolymer.

16. A hydrogel copoloymer according to Claim 11 wherein said silicone monomer is

where a is an integer from 1 to 5 and b is an integer from 0 to 6, A is selected from the group consisting of C,-C₅ alkyl groups and phenyl groups, R is selected from the group consisting of a methyl group (CH₃) and hydrogen, X and Y are selected from the group consisting of C₁ to C₅ alkyl groups, phenyl groups and Z groups wherein Z is a group of the structure

-

where a and A are as defined previously, and φ is a phenyl group.

17. A hydrogel copolymer according to Claim 11 wherein said silicone monomer is selected from the group consisting of methyldi(trimethylsiloxy)silyl- propylglycerol methacrylate, methylidi(trimethyl- siloxy)silylpropylglycerolethyl methacrylate, m,p- styrlethyltrimethylsilane, m,p-styrylethyltris- (trimethylisiloxy)silane, methylacryloxypropyltris- (trimethylsiloxy)silane and 4-(3-trimethylsilylpropyl)- benzylstyrene sulfonate.

18. A hydrogel copolymer according to Claim 11 further comprising, by weight, about 0.01 to about 5 percent, of an initiator selected from the group consisting of 2,2 '-azobis(2,4-dimethylvalero- nitrile) , azobisisobutyronitrile, benzoinmethylether, di(sec-butyl)peroxydicarbonate, and isopropylperoxydicarbonate.

19. A hydrogel copolymer according to Claim 11 further comprising, by weight, about 0.05 to about 2 percent of a crosslinker selected from the group consisting of a silicon-containing crosslinker, a fluorine-containing crosslinker, ethyleneglycoldi- methacrylate and mixtures thereof.

20. A hydrogel copolymer useful for making pliable contact lenses, said copolymer comprising, by weight:

(a) from about 40 to about 90 percent of α-methylene-N-methylpyrrolidone and

(b) from about 10 to about 60 percent of a polymerizable fluoromonamer selected from the group consisting of fluoroacrylates, styryl fluoromonomers and vinyl fluoromonomers.

21. A hydrogel copolymer according to Claim 20 further comprising, by weight:

(c) from about 1 to about 15 percent of a polymerizable hydrophobic non-hydrolyzable silicone monomer;

(d) from about 0.01 to about 5 percent of an initiator selected from the group consisting of claim 1 further comprising, by weight, about 0.01 to about 5 percent, of an initiator selected from the group consisting of 2,2*-azobis(2,4-dimethylvalero- nitrile) , azobisisobutyronitrile, benzoinmethylether, di(sec-butyl)peroxydicarbonate, and isopropylperoxydicarbonate; and (e) from about 0.05 to about 2 percent of a crosslinker selected from the group consisting of claim 1 further comprising, by weight, 0.05 to about 2 percent of a crosslinker selected from the group consisting of a silicon-containing crosslinker, a fluorine-containing crosslinker, and ethyleneglycol- dimethacrylate mixtures thereof.

22. A hydrogel copolymer according to Claim 20 or 21 further comprising, by weight, from about 10 to about 25 percent of a polymerizable hydrophilic monomer selected from the group consisting of methacrylic acid, 2-hydroxyethylmethacrylate, N-vinyl-2-pyrrolidone and N,N-dimethylacrylamide.

23. A hydrogel copolymer according to Claim 20 wherein the weight of the α-methylene-N- methylpyrrolidine is about 60 to about 80 percent by weight.

24. A hydrogel copolymer according to claim 20 wherein the weight of said fluoromonomer is about 20 percent to about 40 percent of the weight of said copolymer.

25. A hydrogel copolymer according to claim 20 wherein said styryl fluoromonomer is selected from the group consisting of pentafluorostyrene, p-vinyl benzyltrifluoroacetate and p-vinyl benzyl hexafluoroisopropylether.

26. A hydrogel copoloymer according to claim 20 wherein said silicone monomer is

where a is an integer from 1 to 5 and b is an integer from 0 to 6, A is selected from the group consisting of C_j-C_j alkyl groups and phenyl groups, R is selected from the group consisting of a methyl group (CH₃) and hydrogen, X and Y are selected from the group consisting of C. to C₅ alkyl groups, phenyl groups and Z groups wherein Z is a group of the structure

where a and A are as defined previously, and φ is a phenyl group.

27. A hydrogel copolymer according to Claim 20 wherein said silicone monomer is selected from the group, consisting of methyldi(trimethylsiloxy)silyl- propylglycerol methacrylate, methylidi(trimethyl- siloxy)silylpropylglycerolethyl methacrylate, m,p- styrlethyltrimethylsilane, m,p-styrylethyltris- (trimethylisiloxy)silane, methylacryloxypropyltris- (trimethylsiloxy)silane and 4-(3-trimethylsilylpropyl)- benzylstyrene sulfonate.

28. A contact lens made from the hydrogel copolymer of Claims 1, 11 or 20.