Extended wear ophthalmic lens
A method for making a silicone hydrogel contact lens is provided. In one embodiment, a prepolymer mixture is polymerized in a lens mold in an atmosphere having less than about 10000 ppm oxygen to form a silicone hydrogel contact lens suitable for extended wear as characterized by producing less than 10% corneal swelling after a period of continuous wear of 7 days including normal sleep periods. In one embodiment, the prepolymer mixture comprises at least one oxyperm material containing hydrophilic groups, wherein the at least one oxyperm material is a siloxane-containing macromer or monomer, at least one ionoperm material, and a cross-linking agent. In certain embodiments, the polymerization of the prepolymer mixture may be carried out in an atmosphere having less than about 1000 ppm oxygen.
1. A method for making a silicone hydrogel contact lens, comprising a step of:
polymerizing a prepolymer mixture in a lens mold in an atmosphere having less than about 10000 ppm oxygen to form a silicone hydrogel contact lens suitable for extended wear as characterized by having on-eye movement with blinking and producing less than 10% corneal swelling after a period of continuous wear of 7 days including normal sleep periods,
wherein the prepolymer mixture comprises
(a) at least one oxyperm material containing hydrophilic groups, wherein the at least one oxyperm material is a siloxane-containing macromer or monomer;
(b) at least one ionoperm material selected from the group consisting of acrylates, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, dimethylacrylate, poly(ethyleneglycol), N-vinylpyrrolidone, and mixtures thereof, and
(c) a cross-linking agent, and the method further comprising
extracting the silicone hydrogel contact lens with a solvent to remove unreacted monomers, wherein the mold includes at least two mold halves.
2. The method of claim 1 , wherein the polymerization of the prepolymer mixture is carried out in an atmosphere having less than about 1000 ppm oxygen.
3. The method of claim 1 , wherein the method further comprises (1) degassing the prepolymer mixture, (2) filling the degassed prepolymer mixture in the mold, (3) sealing the mold halves to one another.
4. The method of claim 1 , wherein the mold is stored in nitrogen.
5. The method of claim 1 , wherein the crosslinking agent is selected from the group consisting of allyl(meth)acrylate, lower alkylene glycol di(meth)acrylate, poly lower alkylene glycol di(meth)acrylate, lower alkylene di(meth)acrylate, divinyl ether, divinyl sulfone, divinylbenzene, trivinylbenzene, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, bisphenol A di(meth)acrylate, methylenebis(meth)acrylamide, triallyl phthalate, and diallyl phthalate.