초록 ▼

Optically clear soft contact lenses of aqueous swollen solid polyvinyl alcohol having a weight average molecular weight of at least 6,000, having been annealed under crystallinity promoting conditions to effectively increase the elastic modulus of the swollen lenses, and optionally subsequently cros

Optically clear soft contact lenses of aqueous swollen solid polyvinyl alcohol having a weight average molecular weight of at least 6,000, having been annealed under crystallinity promoting conditions to effectively increase the elastic modulus of the swollen lenses, and optionally subsequently crosslinked, and methods of preparation and the use thereof are disclosed. The lenses are characterized by their relatively high oxygen transmissibility, sufficient to meet the needs of the human cornea, high optical clarity, improved hot water resistance and superior mechanical properties.

대표청구항 ▼

A process for preparing an optically clear soft contact lens of swollen solid polyvinyl alcohol having a weight average molecular weight of at least about 6,000, which has been annealed, without prior crosslinking, under crystallinity promoting conditions, to substantially increase the crystallinity

A process for preparing an optically clear soft contact lens of swollen solid polyvinyl alcohol having a weight average molecular weight of at least about 6,000, which has been annealed, without prior crosslinking, under crystallinity promoting conditions, to substantially increase the crystallinity thereof, and swollen in a swelling solvent, the resultant annealed, swollen lens possessing an oxygen transmissibility capability in an aqueous environment in excess of that necessary to meet the needs of the human cornea comprising: (a) forming a lens blank from a substantially non-crosslinked polyvinyl alcohol resin having a weight average molecular weight of at least 6,000; (b) annealing said lens blank under crystallinity promoting conditions to effectively increase the elastic modulus of the subsequently swollen contact lens, such that the resulting annealed polyvinyl alcohol blank has a degree of crystallinity between about 0.195 and 0.70 based on the weight fraction of crystalline material present in the polyvinyl alcohol polymer; (c) removing selected portions of said annealed blank until the remainder of the annealed blank constitutes a replica of said contact lens on a reduced scale; and (d) swelling said annealed replica in an aqueous or nonaqueous swelling solvent, to obtain said substantially shape-retaining swollen contact lens, wherein said lens in its swollen equilibrium state with ocular tear fluid, possesses sufficient oxygen transmissibility to meet the needs of the human cornea.