Extended Wear Ophthalmic Lens
An ophthalmic lens suited for extended-wear periods of at least one day on the eye without a clinically significant amount of corneal swelling and without substantial wearer discomfort. In one embodiment, an opthalmic lens is a copolymerization product of at least one oxyperm, at least one ionoperm, and a crosslinker. In one embodiment, a lens has a tensile modulus of less than about 3.0 MPa, yet in another embodiment, the tensile modulus is between about 0.5 to about 1.5 MPa.
1 . A contact lens comprising a polymeric material formed from a prepolymerization mixture including:
(a) at least one oxyperm material containing hydrophilic groups, wherein the at least one oxyperm material is a polydimethylsiloxane-containing macromer or monomer;
(b) at least one ionperm 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 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,
the contact lens characterized by having a tensile modulus of less than about 3.0 MPa and producing less than 10% corneal swelling after a period of continuous wear of 7 days including normal sleep periods.
2 . The contact lens of claim 1 , wherein the tensile modulus is between about 0.5 to about 1.5 MPa.
3 . The contact lens of claim 2 producing less than 7% corneal swelling after a period of continuous wear of 7 days including normal sleep periods.
4 . The contact lens of claim 2 producing less than 5% corneal swelling after a period of continuous wear of 7 days including normal sleep periods.
5 . The contact lens of claim 2 , wherein the cross-linking agent is a lower alkylene glycol di(meth)acrylate or poly lower alkylene glycol di(meth)acrylate.
6 . The contact lens of claim 5 , wherein the prepolymerization mixture comprises 2-hydroxyethyl methacrylate, N,N-dimethylacrylamide, N-vinylpyrrolidone, or a combination thereof.
7 . The contact lens of claim 6 , wherein the prepolymerization mixture includes a polydimethylsiloxane-containing monomer containing hydrophilic groups.
8 . The contact lens of claim 6 , wherein the prepolymerization mixture includes a polydimethylsiloxane-containing macromer.
9 . The contact lens of claim 6 , wherein the contact lens has a hydrophilic surface.
10 . The contact lens of claim 6 , wherein said ophthalmic lens has an oxygen transmissibility of at least 70 barrers/mm and an ion permeability characterized either by (1) an Ionoton Ion Permeability Coefficient of no less than 0.2×10 −6 cm 2 /sec, or (2) an Ionoflux Diffussion Coefficient of no less than 2.6×10 −6 mm 2 /min.