Advances in polyvinyl alcohol hydrogel keratoprostheses: protection against ultraviolet light and fabrication by a molding process.

Our goal was to: 1) modify poly(vinyl alcohol) hydrogels intended for use in a synthetic cornea to absorb ultraviolet light and 2) develop molding procedures for the fabrication of the device. Two ultraviolet light-absorbing monomers were incorporated by copolymerization. The resulting hydrogels protected against ultraviolet light, were not toxic to corneal fibroblasts, and the protection did not diminish during prolonged aqueous exposure. A novel keratoprosthesis molding procedure was developed that made use of the phase transition properties of mixtures of poly(vinyl-trifluoroacetate) and acetonitrile. In this procedure the keratoprosthesis was shaped and a fibrous skirt was bonded to it in a single operation. Composite keratoprostheses were designed and prepared for in vivo testing.