SILICONE METHACRYLATE HYDROGELS FOR CONTACT LENSES

Abstract: Contact lens polymers, i.e. polymers having optical and mechanical properties suitable for use in contact lenses, consisting essentially of copolymers of siloxane monomethacrylates and dimethacrylates, and copolymers of such materials with vinyl pyrrolidinone and pentafluorostyrene and also with methyl methacrylate and methacrylic acid, as exemplary of classes of monomers which may be included in the lens polymer system.

Description: SILICONE METHACRYLATE HYDROGΞLS FOR CONTACT LENSES Technical Field This invention relates to optical contact lenses and, more particularly, to optical contact lenses, lens materials and optical quality copolymers having qualities rendering them suitable for use in optical contact lenses, e.g. clarity, machinability, strength and durability, arid which also possess unique and vastly improved oxygen permeability and wettability. The lenses of this invention and the lens polymers, « i.e., copolymer systems which possess qualities rendering them suitable for use in optical contact lenses, are copolymers of silicone monomers and prepolymers, and acrylate and methacr late monomers, and .include substituents which vastly improve wettability and oxygen permeability such as pentafluorostyrene,and vinyl pyrrolidinone to improve wettability. Background Art The prior art teaches the use of many different polymeric materials in contact lenses. However, although these polymers possess the optical clarity necessary for corrective lenses, they suffer from other characteristics which reduce their potential utility. Polymethylmethacrylate is rigid and durable but relatively impermeable to oxygen. The hydrogel materials based on hydrophilic polymers such as polyhydroxyethyl- methacrylate are soft and have poor durability. In additio they provide an environment which is favorable for bacterial growth and are only moderately impermeable "to oxygen. Silicone rubber is soft and resilient and is highly permeable to oxygen. However, due to the low strength of polysiloxanes, a filler which increases the refractive inde of the mixture, must be added to improve the durability. c. Further, the precision machining and polishing which is necessary in the fabrication of a corrective contact lens is extremely dif icult with the elastomeric silicone rubbers. Accordingly, it would be highly desirable to provide a polymeric material suitable for use in fabricating contact lenses ' having increased oxygen permeability, improved mechanical strength, and which is sufficiently rigid to permit precision machining and polish.ing. I have now discovered novel copolymer materials which possess these properties. The prior art also teaches copolymers prepared by copolymerizing a polysiloxanylalkyl ester of acrylic or methacrylic acid with an alkanol ester of acrylic or methacr lic acid. In these copolymers the polysilo¬ xanylalkyl ester monomer has the structural formula wherei X and Y are selected from the class consisting of C,-C 5 alkyl groups, phenyl groups and Z groups; Z is group of the structure A is selected from the class consisting of C,-C_ alkyl groups and phenyϊ -groups; R is selected from the class consisting of methyl groups and hydrogen; m is an integer from one to five; and n is an integer from one to three. In the a.lkanol ester comonomers, the alkyl group contains from 1 to 20 carbon atoms. The polysiloxanylalkyl ester comonoers in these copolymers were: pentamethyldisiloxanylmethyl inethacrylate C hepta ethyltrisiloxanylethyl acrylate tris(trimethylsiloxy-7-methacr loxypropylsilane phenyltetramethyldisiloxanylethyl acrylate phenyltetraethyldisiloxanylether methacrylate triphenyld-unethyldisiloxanylmethyl acrylate isobuty___hexamethyltrisiloxanylmethyl methacrylate methyldi(trimethylsiloxy)-methacryloxymethylsilane O ?I n-propyloctamethyltetrasiloxanylpropyl methacrylate pentamethyldi(trimethylsiloxy)-acr loxymethylsilane t-butyltetramethyldisiloxanylethyl acrylate n-pentylhexamethyltrisiloxanylmethyl methacrylate tri-i-propyltetramethyltrisiloxanylethyl acrylate Representative alkanol ester comonomers included: methyl acrylate and methacrylate ethyl acrylate and methacrylate propyl acrylate and methacrylate isopropyl acrylate and methacrylate butyl acrylate and methacrylate amyl acrylate and methacrylate hexyl acrylate and methacrylate heptyl acrylate and methacrylate octyl acrylate and methacrylate 2-ethylhexyl acrylate and methacrylate ' nonyl acrylate and methacrylate decyl acrylate and methacrylate undecyl acrylate and methacrylate " lauryl acrylate and methacrylate cetyl acrylate and methacrylate octadecyl acrylate and methacrylate These copolymers of the prior art comprise about 10-60 parts by weight of one or more of the polysilo- xanylalkyl ester monomers copolymerizεd with about 49-90 parts by weight of one or more of the alkanol ester comonomers. These prior art copolymers were prepared by- contacting the mixture of comonomers with a free radical generating polymerization initiator of the type commonly used in polymerizing ethylenically unsaturated compounds. Representative free radical polymerization initiators .include: acetyl peroxide lauroyl peroxide decanoyl peroxide caprylyl peroxide benzoyl peroxide tertiarybutyl peroxypivalate diisopropyl peroxycarbonate tertiarybutyl peroctoate a, a f -azobisisobutyronitrile Conventional polymerization techniques were employed to produce these copolymers. The comonomer mixture containing between about 0.05-2% by weight of the free radical initiator is heated to a temperature between 30 β C.-100 β C, preferably below 70 β C, to initiate and complete the polymerization. The polymerization can be carried out directly in a contact lens mold to form a lens generally having the desired configuration. Alternatively, the polymerization mixture can be heated C Λ ' in a suitable mold or container to form discs, rods or sheets which can then be machined to the desired shape using conventional equipment and procedures employed for fabricating lenses from polymethyl methacrylate. The temperature is preferably maintained below 70 β C. in order to minimize the formation of bubbles in the copolymer. Instead of employing the bulk polymerization techniques described above, one can employ solution, emulsion or suspension polymerization to prepare the novel copolymers, using techniques conventionally used in the preparation of polymers from ethylenically unsaturated monomers. The copolymer thus produced may be extruded, pressed or molded .into rods, sheets or other convenient shapes which are then mach-ined to produce the contact lenses. The aforementioned silicone-acrylate copolymers, descr.ibed more fully_in U.S. Patent No. 3,808,178, had increased oxygen permeability as compared with acrylic polymers and increased wettability as compared with silicone rubber. Improve wettability was imparted to the copolymer by the addition of from about 0.1% to about 10% by weight of one or more hydrophilic monomers to the copolymerization mixture. Such monomers include hydroxyalkyl acr lates and methacrylates wherein the alkyl group contains 1 to 4 carbon atoms, acrylic and methacrylic acid, acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylami glycidyl acrylate and methacrylate and N-vinylpyrrolidone. Alternatively, the wettability of the surface of contact lenses made from these copolymers was improved by the application of a wetting agent such as, for example, a dilute aqueous solution of alkyldimethylbenzylammonium chloride, by exposure of the surface to a corona discharge or by chemical treatment of the surface with a strong oxidizing agent such as nitric acid. c:.- The rigidit of the contact lenses prepared from such copolymers could be' varied by changing the ratio of comonomers and/or their chemical composition. Contact lenses prepared from acrylate monomers are more flexible than those prepared from methacrylate monomers. A copolymer of a polysiloxanylalkyl methacrylate and an alkyl methacrylate fabricated into a contact lens is more rigid than a lens prepared from the copolymer of the corresponding acrylates. The lower the alkyl methacrylate content of the copolymer the more flexible the contact lens prepared therefrom. The rigidity of a contact lens prepared from the aforesaid materials could be increased by the incorporation into the copolymer composition of 0.01% to about 2% by weight of a crosslinking monomer such as a polyol dimethacrylate or diacrylate or a polyol acrylic ester of higher functionality, for example, ethylene glycol dimethacrylate, butylene glycol dimethacrylate, neopentyl glycol diacrylate and pentacrythritol triacr late or tetra-acrylate. The refractive index of polymethylmethacr late, the polymer most widely used in the . fabrication of contact lenses, is 1.49. The refractive indices of the copolymers referred to above could be varied between 1.35 and 1.50 by varying the ratio and nature of the comonomers. In general, increasing the polysiloxanyl monomer content of the copolymer will decrease its. refractive index. The nature of the substituents on the silicon atoms of the polysiloxanyl monomer also importantly affects the refractive index of the copolymer. Lower straight chain alkyl substituents produce copolymers of lower refractive index while polysiloxanyl monomers having phenyl substituents on.the silicon atoms yield copolymers having a higher refractive index. (See U.S. Patent 3,808,178) Statement of the Invention The present invention is an improvement over the prior art lenses and comprises lenses, lens polymers and methods of preparing contact lenses and contact lens polymers of specific and unique copolymeric composition having unique and surprising advantages. In one facet, the invention features copolymers of acrylate and siloxane monomers in which each end of the siloxane is capped with an acrylic or methacrylic acid moiety, the polymer comprising a pol (diacr lie siloxane). In another facet, the invention ' features particular copolymers of monoacrylic siloxane, as described " in the aforesaid prior art patent, and diacr lie siloxane, such copolymers possessing very much improved and unexpected advantages over the prior art and also possessing properties not predictable from known characteristics of prior art polymer- and copolymer systems. In an additional facet, the invention features particular copolymers which include a pentfluorostyrene moiety which vastly improves oxygen permeability and yet possess highly advantageous characteristics as a lens polymer. Still another and very important facet of the invention is a particular set of copolymers of wettable poly(hydroxyalkyl methacrylate-siloxane-methacrylate-n- vinyl pyrrolidinone) which have extremely high wettability and yet are clear and otherwise suitable as lens polymers. Lenses made of the aforementioned copolymer systems and methods of forming the same are also facets of this invention. The term "lens polymer" is commonly and widely used in the contact lens industry and is used herein to mean a polymer or copolymer material which possesses physical and optical characteristics which render the material suitable for being formed into and used as a lens, and in this particular application, as a contact lens. Such material must be clear, have an adequately high refractive index, i.e., above about 1.25 and generally up to about ' 1.5, the higher the refractive index the more correction availability, and must also be firm and rigid enough to be machined and polished, and tough enough to be handled and worn as a contact lens. These characteristics of contact lens polymers are well and generally known in the industry and need not be quantified. Indeed, toughness and handleability are not capable of any meaningful quantitative definition, though hardness and resilience are included in the general concept of toughness. In a more specific sense the present invention includes lenses formed from a lens polymer consisting essentially of the solid polymerization product of comonomers consisting essentially of: (a) from about 5 weight percent to about 99 weight percent silicone monoacrylate or methacrylate having the formula: wherein: R j 8. R1_1 rt 0 R1_12._ R, is a group selected from -0-; -Si-O-; or -Si-O-Si-O-; 1 t i l 9 R lλ R 13 R j is a group selected from -C H 2 _ +1 ; -C β H 5 ; R, is a group selected from m being a positive integer from 1 to 3; R 4 through R 13 ^ clusive , each is a group selected from C n H 2n + l' "W ° r [-°- Si -< CH 2>]n- R 14' ' or wherein when any of R. through R 13 is other than -CH- then the substituents R on adjacent siloxane groups, R -O-Si- k * XΛ - C n H 2 n +l or ^β^S . and wherein n is a positive integer from 1 to 5; and (b) from about 1 weight percent to about 95 weight percent silicone diacrylate or dimethacrylate having the formula wherein: R, is a group selected from -O-; R, and R_, each is a group selected from (CH 2 ) n -; m being a positive integer from 1 to 3; R. through R 13 , inclusive, each is a group selected from Vtort' " Vs' ° r [- 0 - Si - ( - CH 2>]n- R 14 ; C..: R-. is a group selected from ~ c n H 2n+ ^; -CgH 5 or [-0-Si-(CH 2 ) 2 ] n -R. 5 R-- is a group selected from *" c n H 2+1 ; -C 8 H 5 ; .and wherein when any of R 4 through R., is other than —CH,, then the substituents R on adjacent siloxane groups, are - C n H 2n+l or ~ C 6 H 5 and wherein n is a positive integer from 1 to 5. " In a still more specific sense the present invention includes lens polymers which have physical and optical properties suitable for being formed into contact lenses consisting essentially of the polymerization product of the following comonomers: (a) from about 5 to about 99 percent by weight of a silicone monoacrylate or monomethacrylate having the formula wherein: R. is a group selected from -O-; R2, is a g 3 rou r p selected from -CnH2,n+ ■ l, or -C6.-H5,-. R, is a group selected from m being a positive integer from 1 to 3; 4 through R χ3 , inclusive, each is a group selected from and wherein when any of R, through R-, is other than -CH,, then the substituents R on adjacent siloxane groups, R 1 -O-Si- I — - R are - C 2 H 2n+l °. r "C 6 H 5 ; and whereiln n is a positive integer from 1 to 3; and (b) from about 1 to about 95 percent by weight of a silicone diacrylate or dimethacrylate having the formula: wherein: R 8 flO fl2 R. is agroup selected from -O-; -Si-O-; or -Si-O-Si-O-; 1 1 1 R 9 R χl R 13 R- and R, ,each is a group selected from m being a positive integer from 1 to 3; 4 through R.,', inclusive, each is a group selected from wherein when any of R 4 through R-, is other than -CH 3 , then the substituents R on adjacent siloxane groups, R -O-Si- I R are - C n H 2n+l or - C 6 H 5 and wh-erein n is a positive integer from 1 to 3. Representative silicone monomethacrylates include: tris (trimethylsiloxy) silylpropyl methacrylate penta methyldisiloxane methyl methacrylate heptamethyltrisiloxanemethyl methacrylate hexamethyl (trimethylsiloxy) trisiloxane methyl methacrylate pentamethyl-bis (trimethylsiloxy) trisiloxane methyl methacrylate nonamethyl-bis (pentamethyldisiloxanyl) pentasiloxanemethyl methacrylate ' tris (pentamethyldisiloxanyl) silylpropyl methacrylate pyrrolidinonylethyldimethyl siloxy-bis (trimethylsiloxy) silylpropyl methacrylate. Exemplary silicone diacrylates and dimethacrylates include: 1,3 - Bis-methacryloxy methyl 1,1,3,3 - tetramethyl disiloxane 1, 3 Bis - methacryloxypropyl - 1,1,3,3 - tetra is (trimethylsiloxy) disiloxane hexamethyltrisiloxane-bis (methyl methacrylate) tetramethyl-bis (trimethylsiloxy) trisiloxane-bis (methyl methacrylate) - pentamet yl tr methylsiloxy) trisilane-bis dimethyl methacrylate 1,5 Bis - methacryloxy propyl 1,1,5,5 - tetrakis (trimethylsiloxy) 3,3 - dimethyltrisiloxane 1,3 Bis - methacryloxypropyl 1,1,3,3 - tetrakis (pentamethyldisiloxanyl) disiloxane tetra et y -tr me y s oxy-pyrro d nonyld methyls loxy- trisiloxane-bis (methyl methacrylate) The Preferred Embodiments Silicone dimethacrylate (diacrylate) esters, which are new to the art, have been copolymerized with specific hydrophilic monomers to give hydrogels with excellent optical properties in the hydrated state. The hydration level of these hydrogels may be adjusted over a wide range, by incorporating silicone methacrylate esters in the hydrogel formulation. A wide variety of lens types and prescriptions may be fabricated, which has not been possible with previous hydrogel formulations. A further advantage of these formulations lies in the fact that they combine high oxygen permeability with good wetting. As with the siloxane methacrylate esters, the oxygen permeability of the silicone dimethacrylate esters shows a wide variation within the group. The silicone dimethacrylate ester monomer has the structure where X and Y are selected from the class consisting of C l ~ C 3 a ^ l groups, phenyl groups, pentafluorophenyl groups, pyrrolidinonylethyl groups, pyrrolidinonylpropyl groups and 2 groups; Z is a group of the structure A and B are selected from the class consisting of C, - C 3 alkyl groups, phenyl groups, pentafluorophenyl groups, pyrrolidinonyl ethyl groups, pyrrolidinonyl propyl groups. R is selected from the class consisting of methyl groups and hydrogen, m is an integer from zero to five; ' is an integer from one to five; n is an integer from one to three. c:: One embodiment of the invention provides an optical contact lens having clarity, wettability and machinability and having superior oxygen permeability consisting essentially of the polymerization product of the following with suitable polymerization initiators: (a) from 15 percent to 75 percent of tris (trimethylsiloxy) silylpropyl metacrylate or 1, 3-bis-methacryloxypropyl-l, 1, 3, 3-tetrakis- ( rimethylsiloxy)-disiloxane or mixtures thereof; (b) from 10 to 55 percent of vinyl pyrrolidinone or alkoxy methacrylate or mixtures thereof; and (c) optionally up to about 30 percent penta¬ fluorostyrene; and (d) optionally up to about 30 percent methyl methacrylate. Another embodiment of the invention provides an optical contact lens having clarity, wettability and machinability and having superior oxygen permeability consisting essentially of the polymerization product of the following with suitable polymerization initiators: (a) from 15 percent to 75 percent of tris (trimethylsiloxy) silylpropyl methacrylate or 1, 3-bis-methacryloxypropyl-l, 1, 3, 3-tetrakis (trimethylsiloxy)-disiloxane, or mixtures thereof, in a ratio of from 1:100 to 100:1; ' (b) from 3 percent to 30 percent of alkoxy methacrylate; and (c) optionally up to 55 percent of vinyl pyrrolidinone. A further optical contact lens according to this invention has clarity, wettability and machinability and superior oxygen permeability and consists essentially of the polymerization product of the following with suitable polymerization initiators: (a) from 15 percent to 30 percent of tris (trimethylsiloxy) silylpropyl methacrylate or 1, 3-bis-methacryloxypropyl-l, 1, 3, 3-tetrakis- (trimethylsiloxy) -disiloxane, or mixtures thereof; and (b) from 20 percent to 60 percent of vinyl pyrrolidinone. The invention also provides an optical- contact lens having clarity, wettability and machinability and having superior oxygen permeability consisting essentially of the polymerization product of the following with suitable polymerization initiators: (a) from 15 percent to 85 percent of tris (trimethylsiloxy) silylpropyl methacrylate or 1, 3-bis-methacryloxypropyl-l, 1, 3, 3-tetrakis- (trimethylsiloxy)-disiloxane, or mixtures thereof, in a ratio of from 1:100 to 100:1; and (b) from 10 percent to 25 percent of pentafluoros yrene. In another embodiment there is provided an optical contact lens -having clarity, wettability and machinability and having superior oxygen permeability consisting essentially of the polymerization product of the following with suitable polymerization initiators: (a) from 15 percent to 85 percent of tris (trimethylsiloxy) silylpropyl methacrylate or 1, 3-bis-methacryloxypropyl 1-1, 1, 3, 3-tetrakis (trimethylsiloxy)-disiloxane, or mixtures thereof, in a ratio of from 1:100 to 100:1; (b) optionally up to 10 percent of alkoxy methacrylate; (c) optionally up to 30 percent of vinyl pyrrolidinone; and (d) from 10 percent to 25 percent of pentafluorostyrene. Example 1 1, 5 Bis (methacryloxypropyl) - 18.00g 1, 1, 5, 5-tetrakis (trimethylsiloxy) 3, 3-dimethyl trisiloxane 5 N-vinyl pyrrolidinone 13.00g Methacrylic Acid 0.20g Neozapon FLE (BASF)* (as a colorant) O.Olg 2, 2'Azobis - (2, 4-dimethyl - 0.03g 4-methoxyvaleronitrile (VAZO 52) 10 Tert. Butyl peroctoate 1 drop (Esperox 28M, Whitco Chemical Co.) The above were thoroughly mixed, placed in molds and cured at 79°C for five hours. The ' lens blanks were hard and clear with an equilibrium hydration level of 15 13.7%. *Badische Analin & Sodofabrik trademark for copper phthalacyonine dye 0 Example 2 1, 5 Bis (methacryloxy propyl) 15 . 00g 1, 1_,5 , 5 - tetrakis (trimethylsiloxy) 3 ,5 - dimethyl-trisiloxane N-vinyl pyrrolidinone 25 .00g 5 Methacrylic Acid 0 .30g Neozapon FLE (BASF) O . Olg 2, 2 'Azobis- (2 , 4-dimethyl - 0.02g 4-methoxyraleronitrile) Tert. Butyl peroctoate 1 drop 0 The above were thoroughly mixed, placed in molds and cured at 80*C for twenty-four hours. The blanks were opaque, and not suitable for lenses. 5 Example 3 Tris (trimethylsiloxy) silylpropyl 9.00g Methacrylate 1, 5 - Bis (methacryloxy propyl) - l.OOg 1, 1*, 5, 5* - tetrakis (trimethylsiloxy) - 3, 3* - dimethyl-trisiloxane N-vinyl pyrrolidinone ll.lOg Methacrylic Acid l.OOg USP 245 2 drops The above were thoroughly mixed and then cured at 86 β C for sixteen hours. The lens blanks were hard and clear, machined and polished very well. The equilibrium hydration level was 23.5%. Example 4 Tris (trimethylsiloxy) silyl propyl 5.00g Methacrylate .1, 5 - Bis (methacryloxypropyl) 5.00g 1, 1', 5, 5' - tetrakis (trimethylsiloxy) 3,3-dimethyl-trisilσxane N-vinyl Pyrrolidinone ll.OOg Methacrylic Acid l.OOg USP 245 (2, 5-dimethyl-2, 5-bis 3 drops (2-ethyl hexoyl) peroxide hexane) The above were thoroughly mixed and then cured at 84-86.5°C for eighteen hours. The lens blanks were hard and clear, machined and polished very well. The equilibrium hydration level was 17.4%. ' Example 5 Tris (trimethylsiloxy) silylpropyl 9.00g Methacrylate 1, 5 - Bis (methacryloxypropyl) - l.OOg 1, 1', 5, 5' - tetrakis (trimethylsiloxy) - 3, 3' - dimethyl-trisiloxane 'N-vinyl Pyrrolidinone 11.03g USP 245 1 drop The above were thoroughly mixed. Half of the mixture was set aside as a stock solution, the other half was cured at 84-86.5 β C for thirteen hours. The lens blanks were hard and clear, machined and polished well. The equilibrium hydration level was 21.8%. Example 6 The stock solution from example 5 10.13g 2-Hydroxyethyl Methacrylate 2.00g The above were thoroughly mixed and cured at 84-86.5°C for thirteen hours. The lens blanks were hard and clear, machined and polished well. The equilibrium hydration level was 30.0%, the oxygen permeability was very high. Example 7 1, 3 - Bis-methacryloxypropyl - 210.OOg 1, 1, 3, 3 — tetrakis (trimethylsiloxy) disiloxane Tris (trimethylsiloxy) silyl - 180.OOg propyl Methacrylate N-vinyl Pyrrolidinone 120.OOg 2-Methoxyethyl Methacrylate 60.OOg 2-Hydroxyethyl Methacrylate 24.OOg Methacrylic Acid 6.OOg Neozapon Blue FLE 0.15g VAZO 52 O.SOg The above were mixed thoroughly and cured at 75 β C for seven hours, to give lens blanks with good hardness and machinability. Lenses produced from these lens blanks had excellent wetting and exceptional oxygen permeability, DK = 28.5 x 10 at 20°C; see Irving Fatt and Roger St. Helen, "Oxygen Tension Under an Oxygen Permeable Contact Lens,"'American Journal of O tometry 1971, No. 7, p. 545 for dimensions and method of determing DK value. Example 8 1, 3 - Bis-methacryloxypropyl - 7.OOg 1, 1, 3, 3-tetrakis (trimethylsiloxy) - disiloxane Tris (trimethylsiloxy) silyl - . 6.OOg propyl Methacrylate N-(2-Methacryloxyethyl) Pyrrolidinone 4.OOg 2-Methoxyethyl Methacrylate 2.OOg 2-Hydroxyethyl Methacrylate 0.80g Methacrylic Acid 0.20g VAZO 52 . ' 0.10g The above were * mixed thoroughly and cured at 70-73 β C for twenty and one-half hours to give lens blanks with good hardness and machinability. Lenses made from these lens blanks had exceptional oxygen permeability " and excellent wetting. Example 9 1, 3 Bis-methacryloxypropyl 0.30g 1, 1 " , 3, 3*-tetrakis (trimethyl¬ siloxy) disiloxane Tris (trimethylsiloxy) silyl- 7.OOg propyl methacrylate N-vinyl Pyrrolidinone " 13.OOg VAZO 52 0.05g The above were mixed thoroughly and cured at 70-llS°C for one hour and fifteen minutes to give a blank which was opaque. G Example 10 1, 3 Bis-methacryloxypropyl 10.OOg 1,1,3, 3-tetrakis-{trimethylsiloxy) disiloxane Pyrrolidinonyl-2-ethyl-dimethylsiloxy-bis- ' 5.17g (trimethylsilo-xy) silyl propyl Methacrylate Pentafluorostyrene 5.05g VAZO 52 0.05g . The above were mixed thoroughly and cured for six hours from 77-91 β C to give lens blanks with good hardness and machinability. Lenses made from these lens blanks had exceptional oxygen permeability and good wetting. Example 11 1, 3 Bis-methacryloxypropyl 40.OOg 1,1,3, 3-tetrakis (trimethylsiloxy) - disiloxane Tris (trimethylsiloxy) silyl - 35.OOg propyl Methacrylate N-vinyl Pyrrolidinone . 25.OOg Neozapon Blue FLE 0.02g VAZO 52 0.10g The above were thoroughly mixed and cured at 75 β C for seven and one-half hours to give lens blanks with good hardness and machinability. Lenses produced from these lens blanks had exceptional oxygen permeability and excellent wetting. Example 12 1, 3 - Bis-methacryloxypropyl 10.OOg 1,1,3, 3-tetrakis (trimethylsiloxy) disiloxane Tris (trimethylsiloxy) silyl- 5.OOg propyl Methacrylate Pentafluorostyrene 5.05g VAZO 52 (2, 2' Azobis 0.04g (2, 4-dimethylvaleronitrile) The above were mixed thoroughly and cured for three and one-half hours at 73-74 β C to give lens blanks with good hardness and machinability. Lenses made from these lens blanks had exceptional oxygen permeability and good wetting. Example 13 1, 3 Bis-methacryloxypropyl 6.OOg 1,1,3, 3-tetrakis (trimethylsiloxy) - - disoloxane Tris (trimethylsiloxy) silyl - 7.OOg propyl Methacrylate N-vinyl Pyrrolidinone 5.OOg Pentafluorostyrene 2.OOg VAZO 52 0..09g The above were thoroughly mixed and cured at 72-74°C for four hours, to give lens blanks with good hardness and machinability. Lenses made from these lens blanks had exceptional oxygen permeability and excellent wetting. Example 14 1, 3 Bis-methacryloxypropyl - 65.OOg 1,1,3, 3-tetrakis (trimethylsiloxy) - disiloxane N-vinyl Pyrrolidinone 20.OOg 2-Methoxyethyl Methacrylate 10.OOg 2-Ξydroxyethyl Methacrylate 4.OOg Methacrylic Acid l.OOg Neozapon Blue FLE 0.02g VAZO 52 0.04g The above were mixed thoroughly and cured for six hours at 74-76 β C, to give lens blanks with good hardness and fair machinability. Lenses made from these lens blanks had exceptional oxygen permeability and excellent wetting but were somewhat brittle. C-.-F Example 15 1, 3 Bis-methacryloxypropyl - 11.OOg 1,1,3, 3-tetrak.is (trimethyl - siloxy) disiloxane N-vinyl Pyrrolidinone 4.OOg Pentafluorostyrene ' 3.OOg 2-Hydroxyethyl Methacrylate 2.OOg VAZO 52 0.06g The above were thoroughly mixed, . ried over MgSO 4 , filtered and cured at 60-90°C for three hours to give lens blanks with good wetting and superior oxygen transmissibility. Example 16 1, 3 Bis-methacryloxypropyl 11.OOg 1, 1", 3, 3"-tetrakis (trimethyl - siloxy) disiloxane N-vinyl Pyrrolidinone 6.OOg Pentaflyorostyrene 3.OOg VAZO 52 0.06g The above were mixed thoroughly, dried over MgSO 4 , filtered and cured at 60-90 β C for two and one half hours, to give lens blanks with good wett.ing and superior oxygen transmissibility. Example 17 1, 3 Bis-methacryloxypropyl - 10.OOg .1, I', 3, 3'-tetrakis (trimethyl - siloxy) - disiloxane N-vinyl Pyrrolidinone 5.OOg Pentafluorostyrene 2.OOg VAZO 52 0.06g The above were mixed thoroughly, dried over MgSO., filtered, and cured at 60-100 β C for two and one half hours, to give lens blanks with good wetting a-nd superior oxygen transmissibility. Example 18 1, 3 Bis-methacryloxypropyl 4.OOg 1, 1', 3, 3'-tetrakis (trimethyl - siloxy) disiloxane Tris (trimethylsiloxy) silyl - 9.OOg propyl Methacrylate N-vinyl Pyrrolidinone 5.OOg ■ Pentafluorostyrene . 2.OOg VAZO 52 0.07g The above were mixed thoroughly and cured for four hours at 60-80 β C, to give lens blanks with good wetting and superior oxygen transmissibility. Example 19 1, 3 Bis-methacryloxypropyl - 80.OOg 1, 1', 3, 3*-tetrakis (trimethylsiloxy) - disiloxane Tris (trimethylsiloxy) ' silyl - 50.OOg propyl Methacrylate N-vinyl Pyrrolidinone 40.OOg 2-Methoxyethyl Methacrylate 20.OOg 2-Hydroxyethyl Methacrylate 8.OOg Methacrylic Acid 2.OOg Neozapon Blue FLE 0.04g VAZO 52 0.10g The above were thoroughly mixed, dried over MgSO 4 , filtered and cured at 70-75°C, under 2 for 4 to 6 hours. The lens blanks had a hardness of 74-75D and gave lenses with superior wetting and oxygen permeability. Example 20 Tris (trimethylsiloxy) silyl. 6.OOg propyl Methacrylate N-vinyl Pyrrolidinone 5.OOg 2-Hydroxyethyl Methacrylate l.OOg Ethylene Dimethacrylate 0.10g Methacrylic Acid 0.20g VAZO 52 O.Oδg The above were mixed thoroughly and cured for nineteen hours from 60-90 β C, to give lens blanks which hydrated to 44% with superior oxygen permeability. Example 21 1, 3 Bis-methacryloxypropyl 0.30g 1, 1', 3, 3'-tetrakis (trimethyl-siloxy) - disiloxane Tris (trimethyl siloxy). silyl propyl 7.OOg Methacrylate N-vinyl Pyrrolidinone 11.OOg 2-Hydroxyethyl Methacrylate 2.OOg VAZO 52 0.05g The above were mixed and thoroughly dried over MgSO 4 , filtered and cured for two hours at 60-75 β C, to give lens b.lanks with a hydration level of__52% with superior oxygen transmissibility. Example 22 1, 3 Bis-methacryloxypropyl 0.30g 1, I', 3, 3*-tetrakis (trimethyl¬ siloxy)-disiloxane Tris (trimethylsiloxy) silyl-propyl 6.OOg Methacrylate N-vinyl Pyrrolidinone 10.OOg 2-Hydroxyethyl Methacrylate 4.OOg VAZO 52 0.07g The above were mixed thoroughly, dried over MgSO 4 , filtered, and cured at 60-118 β C for four hours, to give lens blanks with a hydration level of 58% and superior oxygen transmissibility. l Example 23 1, 3-Bis-methacryloxypropyl- 0.20g 1, I 1 , 3, 3"-tetrakis (trimethyl- siloxy)-disiloxane Tris (trimethylsiloxy) silyl¬ 6.OOg propyl Methacrylate N-vinyl Pyrrolidinone 7.08g 2-Hydroxyethyl Methacrylate 7.OOg VAZO 52 O.Olg • The above were mixed thoroughly, dried over MgS0 4 , filtered and cured at 60-75°C for four hours to give blanks which were opaque. Example 24 1, 3-Bis-methacryloxypropyl- 7.50g 1, 1 « , 3, 3'-tetrakis (trimethyl¬ siloxy)-disiloxane N-vinyl Pyrrolidinone - 50g 2-Hydroxyethyl Methacrylate 50g Triethyleneglycol Dimethacrylate ' llg Methacrylic Acid 0.10g VAZO 52 O.Oδg The above were mixed thoroughly, dried over MgSO 4 , filtered, and cured for six hours at 70-77°C. The lens blanks had a hardness of 80D and hydrated to 10%, with superior oxygen permeability. Example 25 1, 3-Bis-methacryloxypropyl- 0.30g 1, 1', 3, 3 * -tetrakis (trimethyl- siloxy)-disiloxane Tris (trimethylsiloxy) silyl 9.OOg propyl Methacrylate N-vinyl Pyrrolidinone 5.OOg Methyl Methacrylate 6.OOg VAZO 52 0.10g The above were mixed thoroughly, and cured at 60-76 β C for four and one-half hours, to give lens blanks with good wetting and superior oxygen permeability. Example 26 1, 3-Bis-methacryloxypropyl- 25.OOg 1, 1, 3, 3-tetrakis (pentamethyl¬ disiloxanyl) disiloxane Tris (tri-methyl siloxy) silyl- 7.50g propyl Methacrylate N-vinyl Pyrrolidinone 12.50g 2-Methoxyethyl Methacrylate 2.50g 2-Hydroxyethyl Methacrylate 2.OOg Methacrylic Acid 0.50g VAZO 52 0.16g The above were thoroughly mixed, then degassed under vacuum and repressured to atmospheric pressure with nitrogen. The formulation was cured at 75 β C for seventeen hours, to give lens blanks with good hardness, exceptional oxygen permeability, good wettability, and good optical properties. It has been found, surprisingly, that siloxane methacrylates, which are known to be hydrophobic, may be copolymerized with specific hydrophilic monomers tb give . hydrogels with excellent optical properties in the hydrated state. The hydration level of these hydrogels may be adjusted over a wide range, giving hydrogels which are soft and flexible, to semi-soft and even ridged and hard. Thus, it is possible to fabricate a wide variety of lens types and prescriptions which is not possible, with other hydrogels. A further advantage, of these hydrogels is their extremely high φxygen permeability coupled with excellent wettability. o?.qι It has also been found, that while siloxane methacrylates are oxygen * permeable, there is a wide variation in the oxygen permeability within this group of compounds, a fact which has not previously been reported. In addition, siloxane methacrylates have been prepared which include hydriphilic groups, such as pyrrolidinone, within the molecule, thus enhancing wetting, while also maintaining high .oxygen permeability. The silicone methacrylate (acrylate monomers are best described by the following generalized formulae: where X & Y are selected from the class consisting of C l - 3 alkyl groups, phenyl groups, pentafluorophenyl groups, and Z groupsV Z is a group of the structure where A and B are selected from the class consisting of C^ - C 3 alkyl groups, phenyl groups, pentafluorophenyl ' groups; R is selected from the class consisting of methyl groups and hydrogen; m is a positive integer from one to fiv and n is a positive integer from one to- three. . X, Y, and A may also be pyrrolidinonyl ethyl, pyrrolidinonyl propyl, hydroxyethyl or hydroxy-propyl, or dihydroxy propyl. Surprisingly, there is a. criticality in choosing the hydrophilic comonomer. When -2-hydroxyethyl methacrylate is used with vinyl pyrrolidinone in a ratio of more than about 1:1, (Examples 23 and 32) the resultant lens blank was opaque. N-vinyl pyrrolidinone proved to be a more compatible hydrophilic comonomer, Examples 3-5 giving lens blanks of great clarity over a wide range of compositions. Other comonomers may also be included in the formulation to improve hardness and machinability, of the lens blank in the dry, unhydrated state, such as pentafluorostyrene, styrene, toluene, alkyl methacrylates, such as methyl methacrylate, ether methacrylates, such as methoxyethyl methacrylate and methacrylic acid. Crosslinking comonomers, in very small amounts, are also included in the formulation, such as ethyleneglycol dimethacrylate and triethylene glycol dimethacrylate. Others, known in the art, may also be used. . These phenomena are shown in the following examples. Example 27 Hexamethy1-3-(trimethylsiloxy) 6.OOg tri-.siloxane methyl Methacrylate N-vinyl Pyrrolidinone 5.OOg 2-Hydroxyethyl Methacrylate l.OOg Ethylene Dimethacrylate 0.10g Methacrylic Acid .0.20g 2, 2*-AZO bis (2, 4-d.imethyl- 0.03g valeronitrile) OMF The above were thoroughly mixed and then cured at 75 β C for a total of fourteen hours. The lens blanks were hard and clear, machined and polished well, The equilibrium hydration level was 43%, the oxygen permeabilit was very high. Example 28 Pentamethyl-3,3 f -bis (trimethyl-siloxy) 6.OOg tri-siloxane methyl Methacrylate N-Vinyl Pyrrolidinone 5.OOg 2-Hydroxyethyl Methacrylate l.OOg Ethylene Dimethacrylate 0.10g Methacrylic Acid 0.20g 2,2*-Azobiji (2 4-dimethylvaleronitrile) 0.03g The above were thoroughly mixed and then cured at 75 β C for a total of fourteen hours. The lens blanks were hard and clear, machined and polished well. The equilaibrium hydration.level was 41%, the oxygen permeabili was very high. Example 29 Tris (trimethylsiloxy) silyl-propyl 6.OOg Methacrylate N-Vinyl Pyrrolidinone 5.OOg 2-Hydroxyethyl Methacrylate l.OOg Ethyleneglycol Dimethacrylate 0.10g Methacrylic Acid 0.20g 2,2' Azobis (2,4-dimethylvaleronitrile) 0.06g The above were thoroughly mixed, and cured at 60-68°C for three hours and at 85-93 β C for fourteen hours, giving lens blanks which were clear and colorless, and machined and polished very well. The equilibrium hydration level was 44% and the oxygen permeability was very high. Example 30 Tris (trimethylsiloxy) silylpropyl 3.OOg Methacrylate 2-Pyrrolidinonyl ethyl-dimethyl- 3.OOg siloxy-bis (tri-methyl siloxy)- silylpropyl Methacrylate N-Vinyl Pyrrolidinone 4.OOg 2-Hydroxyethyl Methacrylate 0.50g Triethyleneglycol Dimethacrylate 0.1Og Methacrylic Acid 0.13g 2,2' Azobis (2,4-dimethylvaleronitrile) 0.05g The above were thoroughly mixed and cured at 52-85° for one-half hour and at 85-93°C for fourteen hours. The lens blanks were clear and colorless, they machined and polished very well. The equilibrium hydration level was 23%, the oxygen permeability was very high. Example 31 Tris (trimethylsiloxy) silylpropyl . 50g Methacrylate 1,5-Bis ( ethacryloxy propyl) 0 , .50g i,l,55-tetrakis (trimethylsiloxy) -3,3-d-lmethyl trisiloxane N-Vinyl pyrrolidinone 2. , 50g 2-Hydroxyethyl methacrylate 2. .50g 2,5-Dimethyl-2,5-bis (2-ethyl hexoyl) 1 drop peroxyl hexane The above were thoroughly mixed, placed in molds, and cured for nineteen hours at 99-100 β C. The lens blan were clear and colorless. Example 32 Tris (tri-methylsiloxy) silylpropyl 4.50g Methacrylate 1,5-Bis (methacryloxy propyl) 0.50g 1,1,5,5-tetrakis- (trimethylsiloxy) -3,3-dimethyl tri-siloxane N-Vinyl pyrrolidinone 2.OOg 2-Hydroxyethyl methacrylate 3. OOg 2,5-Dimethyl-2,5-bis (2-ethylhexoyl- 1 drop peroxy) hexane __ _ The above were mixed thoroughly placed in molds in th • oven and cured eighteen hours at 98-100°C. The blanks were opaque. Example 33 Tris (triraethylsiloxy) silylpropyl 4.OOg Methacrylate 1,5 Bis (methacryloxy propyl)- , 0.50g 1,1,5,5-tetrakis (trimethylsiloxy)- 3,3-dimethyl trisiloxane ° N-Vinyl pyrrolidinone 2.50g 2-Hydroxyethyl Methacrylate • 3.OOg 2,5-Dimethyl-2,5-Bis (2-ethylhexoyl) 1 drop perσxyl hexane (U.S.P245 itco Che . Co.) The aboye were thoroughly mixed,placed in molds, 5 and cured at 99-100°C for seventeen hours. The lens blanks were hard, clear, and colorless. The preceding examples and specific compositions and methods which have " been disclosed demonstrate the general nature of the invention and a number of independently 0 significant and unpredictable facets of the invention. In general, hydrophylic monomers which can be reacted with siloxanes of the type described to form either mono- or di-acrylate and methacrylate capped comonomers are suitable for use in this invention. Examples of such 5 capping monomers include the following methacrylates: Glyceryl Mono-Methacrylate 0 Diethyleneglycol Mono Methacrylate O CH, l{ i 3 HOCH 2 CH 2 OCH 2 CH 2 0 C - C = CH 2 Triethyleneglycol Mono Methacrylate 0 CH, 1 I 3 . 5 H0CH 2 CH 2 0CH 2 CH 2 0CH 2 CH 2 0 C - C - CH 2 2-N-Pyrrolidinonylethyl Methacrylate CH CH 2-N-Pyrrolidinonylethoxyethyl Methacrylate CH 2 3-N-Pyrrolidinonylpropyl Methacrylate 3 (2-N-Fy-rrolidinonylethoxy) -2-hydroxypropyl Methacryl CM. - CH. Hydroxyethoxy-2-Hydroxypropyl Methacrylate — " ~- O CH,"- HO - CH 2 CH 2 - O - CH 2 CH - CH 2 - O - £ - * C ■ CH 2 OH O CH. HO CH l ,2C"H"„2 - 0 - CH, - CH, - O - C - k = CH. I 2 CH, i 2 OH 3-Methoxy-2-Hydroxyproρyl Methacrylate CH 3, - O - CH 3 - 0 - 3-Hexafluoroisopropoxy-2-Hydroxy-propyl Methacrylate IE,-1H, 3H tetrafluoropropoxy-2 Hydroxy-propyl Methacrylate Diacetone Methacrylamide Any monomer which is reactive to form capped siloxanes may be considered for use in this invention, such as the acrylates which are analogous to the above methacrylates and the hydrophylic monomers referred to in the discussion of the prior art hereinbefore. Other comonomers .include, in addition to those previously discussed, the following methacrylates and analogous acrylates: Hexafluoro-iso-propyl Methacrylate 1H, 1H, H-tetra uoropropyl Methacrylate O CH 3 HCF 2 CF 2 CH 2 0-C-C=CH 2 c , IH,IH,5H-0ctafluoropenty1 Methacrylate Q CH, HCF 2 CF 2 CF 2 CF 2 CH 2 0 CH. IH,IH,7H-Dodecafluorohepty1 Methacrylate HCF 2 CF 2 CF 2 CF 2 CF 2 CF 2 CH 2 0 C - C - CH 2 IH,IH-Heptafluorobuty1 Methacry1ate TABLE I SlMiATOT OF EXAMPLES Table I - Continued Table I - Continued * Ccapounds listed by class, and percentages, by vaight, rounded and approximated, see the description of the exaπple for exact compound and amounts. **These exanples were carried out in the manner described and exeπplified using the weight percentages stated, but are not separately reported here. VP = vinyl pyrrolidinone (or equivalent derivative thereof; A=Acceptable HEMA = 2-hydroκyethyl methacrylate (or equivalent hydroxyalJcyl acrylate or methacrylate) W=Good wettability PFS = pentafluorostyrene (or equivalent fluoro conpound with a carbon-carbon double bond) A=Superior MA = methacrylic acid MMA a methyl methacrylate IS: (1) Vinyl pyrrolidinonyl moeity attached to siloxane diacrylate comonomer (12) M MAAAA aanndd eetthhyylleennee dαiimmeethnaaccrryyliaattee MAA and trieth lene l col dimethacr late Discoveries and Unexpected Results A number of new characteristics, features and results which could not have been foreseen or predicted from the known lenses, lens materials and lens technology. It was discovered, for example,- that there was a very striking difference in oxygen permeability, both as to permeability constant and rate of attainment of equilibrium of oxygen transmission when mono- and di- acrylate or methacrylate siloxanes were . used as comonomers to form the ultimate lens polymer. Oxygen permeability, at equilibrium, of such lens polymers, e.g. those in all but examples Nos. 27-30, was significantly higher monoacrylate siloxane lens polymers, by a factor of three or more in most instances. For example, the oxygen permeability of the lens polymer of Example 7 has a DK value of 28.5 x 10~ " , using the procedure and nomenclature of Fatt and St. Helen, "Oxygen Tension Under an Oxygen-Permeable Contact Lens", American Journal of Optometry, 1971, No. 7, pp. 545-555, whereas lens polymers described in the prior art Gaylord. U.S. Paten No. 3>808,178 have a DK value of only 4 x 10 , obtained by converting values in said patent to DK values) . equal or . -even greater importance to the user, or. " equilibri in oxygen permeability of the mono- and di- acrylate siloxane lens polymers of this invention is reach very much more rapidly, when the lens is removed from wash or storage liquid and placed in use. This unexpected phenomenon, which cannot yet be explained, is of especial importance for long term users of contact lenses. Prior art lenses often depleted the oxygen at the eye such that when equilibrium was finally reached the eye surface tissues had sustained damage or irritation from which it would not recover during the period the lens is to be worn. Using the aforementioned lens polymers of this invention, no such injury results thus permitting many to wear long CM?! term lenses who might not otherwise be able to do so, making the wearing of long term lenses more comfortable for all users. By way of example, though there is some variability between particular materials, the afore¬ mentioned lens polymers of this invention pass substantial amounts of oxygen through lenses formed thereof within as little as 30 seconds whereas the best prior art lenses, now known to applicant, require 3 to 4 minutes before any significant amount of oxygen reached the other side of. lens≤s. •. ' It was also a surprise to discover that there is a relatively critical ratio of vinyl pyrrolidinone and hydroxyalkyl methacrylate which can be copolymerized with the siloxane methacrylate polymer system of this invention. It was found, for example, that the ratio of hydroxyalkyl methacrylate to vinyl pyrrolidinone must not exceed more than"about 1:1. Any proportion significantly in excess of this ratio results in an opaque material unsuitable for use as a lens polymer. As shown by the examples, the ratio may be- just slightly greater than 1:1 but significantly higher ratios must be avoided. Related to the previous discussion of oxygen permeability, it was discovered that, contrary to what one would predict, the inclusion of siloxane diacrylate and siloxane dimethacrylate does not diminish oxygen permeability in a siloxane based or containLng polymer system. Extrapolating from known permeability, one would predict a significant reduction in oxygen permeabilit of dimethacrylate siloxanes as compared with monomethacryla siloxanes. While the use of dimethacrylate siloxanes might be expected to increase dry hardness of the lens ' polymer, one would not expect to increase oxygen permeability as well. It was found, however, that dimethacrylate siloxane based lens polymers were more O:.-:H oxygen permeable, by a very substantial factor, than monomethacrylate lens polymers, and that the inclusion of even small amounts, e.g. greater than about one weight percent, of the dimethacrylate siloxane greatly improved oxygen permeability. In general, harder lenses are formed with higher amounts of siloxane dimethacrylate or siloxane diacrylate, as compared with monomethacrylates or monoacrylates. Vinyl pyrrolidinone and hydroxyalkyl methacrylates when copolymerized into the lens polymers increase wettability and level of hydration, and increase dry hardness of the lens, improving machinability and general physical characteristics for forming lenses; however, too much of either monomer in the system results in a polymer which is opaque and not-suitable for forming lenses. From about 10 percent (all percentages by weight) to about 55 to 60 percent vinyl pyrrolidinone may be copolymerized with siloxane dimethyl methacrylate (or equivalent di-acrylate capped siloxane) or with mixtures of mon * o— and di— methyl methacrylates (or equivalent mono- and di- acrylate capped siloxanes) , the latter in a ratio of from about 1:2 _0 to 99:1 di- to mono-,acrylate siloxane. The inclusion of a relatively small amount, e.g. as little as five percent, of hydroxyalkyl acrylate or methacrylate tends to increase the compatability of the siloxane system for vinyl pyrrolidinone. Hydroxyalkyl methacrylates and acrylates can be tolerated, and improve wetting and hydration, in amounts of from about ten percent, to significantly improve wetting, to about forty percent. Lesser amounts can be included, of course, but with diminishing effect upon the wettability *" and hydratability of the lens polymer which results from polymerization of the siloxane system with hydroxyalkyl acrylates and methacrylates. Fluorinated vinyl-group containing monomers may be included in amounts of from trace levels to about thirty percent, ten to thirty being the preferred effective range, to increase the wettability and oxygen permeability of the resulting lens polymer, following polymerization of a mixture of mono- and di- methacrylate or acrylate siloxanes, as described before, with the fluorinated vinyl compound, with or without a "wetting" monomer such as vinyl pyrrolidinone or a hydroxyalkyl methacrylate or acrylate. For hard lenses, the ratio of monoacrylate (or methacrylates) siloxane to diacrylates (or methacrylate) siloxane should be from about 1:1 to about 2:1; whereas for soft lenses the ratio of these monomers should be 10:1 or greater. Methacrylic acid and methyl ethacrylate may also be included in the monomeric mixture before polymerization, in amounts of up to about two percent methacrylic acid and up to about thirty percent methyl methacrylate wit destroying the advantages lens polymer characteristics of the subject invention. These monomers, when copolymerized into the polymers of this invention, tend to decrease oxygen permeability slightly but can be tolerated to the degree indicated and tend to improve the machinability of the resulting lens polymers. Another great advantage which is somewhat subjective in observation but is nonetheless real and important in the practical application of the inventive concepts of this invention is that the inclusion of dimethacrylate (or diacrylate) siloxanes with monomethacrylate siloxanes or the use of dimethacrylates* alone provides a very much more stable monomeric system which is easier to handle during pre-polymerization procedures, is easier to copolymerize with the other co-monomers discussed, and gives much more predictable, higher quality lens monomers. Industrial Application Very preliminary trials indicate that not only are lenses of the composition described above suitable for long term use, i.e., continuous wear, 24 hours a day, for weeks or months, but that, as result of wearing these lenses swelling of the cornea, which occurs with other long term lenses, is eliminated and the cornea returns to its normal non-swollen, configuration, thus establishing that the combined characteristics of wettability and oxygen permeability effectively keep the eye fed with essential oxygen during periods of wear. This invention is useful in the manufacture of optical contact lenses and may be used in the manufacture of other optical devices.

Claims: WHAT IS CLAIMED IS: 1. A contact lens composed of ' a material conprismg the solid polymerization product of comonomers comprising: (a) from 5 weight percent to 99 weight percent silicone monoacrylate or methacrylate having the formula: wherein: • R I8- Ri 1 n 0 Λ jR.1-2 : is a group selected from - -; -Si-O-; or -Si- -Si-O-; . R S R ll R 13 R--is a grou selected from -C H- + , ~ c g H ς? . R- is a group selected from C m H 2m+l m being a positive integer from 1 to 3; elected from or wherein when any of R 4 through R-- is other than -CH- then the substituents R on adjacent siloxane groups. are . "C n H 2n + l or - C 6 H 5 and wherein n is a positive integer from 1 to 5; and (b) from 1 weight percent to 95 weight percent silicone diacrylate or dimethacrylate having the formula where-in . is a group selected from -O-; R- and R-, each is a group selected from m being a positive integer from 1 to 3; R. through £-13, inclusive, each is a group selected from C n H 2n+l ? " C 6 H 5 ; or iCR 2 i n "R 14 ; R_ . is a group selected from " * n S 2n+l ? " < " 5 H 5 or R.e is a group selected from ~ H-.-,; -C 8 H-; and wherein when any of R 4 through R.- is other than -CH-, then the substituents R on adjacent siloxane groups. R 1 -O-Si- ■ 3X6 - C n H 2n÷r or "C 6 H 5 ; "" ; " - so - . and wherein n is a positive integer from 1 to 5. 2. A contact lens as claimed in Claim 1, wherein said material results from the copolymerization of said comonomers with the inclusion of from 10 to 55 5 percent vinyl pyrrolidinone. 3. A contact lens as claimed in Claim 1 or 2, wherein said material results from the copolymerization of said comonomers with the inclusion of from 10 to 30 percent fluorinated vinyl compound. 0 4. A contact lens as claimed in Claim 3 wherein the fluorinated vinyl compound is pentafluorostyrene. 5. An optical contact lens having clarity, wettability and machinability and having superior oxygen permeability consisting essentially of the polymerization 5 product of the following with suitable polymerization initiators: (a) from 15 percent to 75 percent of tris (trimethylsiloxy) silylpropyl methacrylate or 1, 3-bis-methacryloxypropyl-l , 1, 3, 3-tetrakis- ' 0 (trimethylsiloxy)-disiloxane or mixtures thereof; (b) from 10 to 55 percent of vinyl pyrrolidinone or alkoxy methacrylate or mixtures thereof; and (c) optionally up to about 30 percent pentafluorostyrene; and 5 (d) optionally up to about 30 percent methyl methacrylate. 6. An optical contact lens having clarity, wettability and machinability and having superior oxygen permeability consisting essentially of the polymerization 0 • product of the following with suitable polymerization initiators: (a) from 15 percent to 75 percent of tris ( trimethylsiloxy) silylpropyl methacrylate or 1, 3-bis-methacryloxypropyl-l, 1, 3, 3-tetrakis 5 ( trimethylsiloxy)-disiloxane, or mixtures thereof, in a ratio of from 1:100 to 100:1; (b) from 3 percent to 30 percent of alkoxy methacrylate; and (c) optionally up to 55 percent of vinyl pyrrolidinone. 5 7. An optical contact lens having clarity, wettability and machinability and having superior oxygen permeability consisting essentially of the polymerization product of the following with suitable polymerization initiators: 0 (a) from 15 percent to 30 percent of tris (trimethylsiloxy) silylpropyl methacrylate or 1, 3-bis-methacryloxypropyl-l, 1, 3, 3-tetrakis- {trimethylsiloxy)-disiloxane, or mixtures thereof; and (b) from 20 percent to 60 percent of vinyl 5 pyrrolidinone. 8. An optical contact lens having clarity, wettability and machinability and having superior oxygen permeability consisting essentially of the polymerization product of the following with suitable polymerization 0 initiators: (a) from 15 percent to 85 percent of tris (trimethylsiloxy) silylpropyl methacrylate or 1, 3-bis * -methacryloxypropyl-l, 1, 3, 3-tetrakis- (trimethylsiloxy)-disiloxane, or mixtures thereof, in 5 a ratio of from 1:100 to 100:1; and (b) from 10 percent to 25 percent of pentafluorostyrene. 9. An optical contact lens having clarity, wettability and machinability and having superior 0 oxygen permeability consisting essentially of the polymerization product of the following with suitable polymerization initiators: (a) from 15 percent to 85 percent of tris (trimethylsiloxy) silylpropyl methacrylate or 1, 3-bis-methacryloxypropyl 1-1, 1, 3, 3-tetrakis ( trimethylsiloxy)-disiloxane, or mixtures thereof, in a ratio of from 1:100 to 100:1; (b) optionally up " to 10 percent of alkoxy methacrylate; (c) optionally up to 30 percent of vinyl pyrrolidinone; and (d) from 10 percent to 25 percent of pentafluorostyrene. OK

Inventors: FOLEY WILLIAM M JR
Applicants: MCCARRY JOHN D
Application year: 1982
Main classification: C08F230
IPC codes: C08F30, G02B1