A new gas permeable hard contact lens.

In reviewing the literature, it becomes apparent that there is continued interest in a gas permeable contact lens. Although silicone is the logical choice of material because of its unusual oxygen permeability, its hydrophobic characteristics, poor centering characteristics, and problems with proper edging have prevented its widespread use. This paper reports on a preliminary study in a group of 25 phakic patients fitted with a lens made of a new material consisting of polymethylmethacrylate in combination with silicone. The material is reported to be gas permeable although advantage is also taken of the lens flexibility to enhance the interchange of tears to maintain normal corneal metabolism. The other advantages of the lens are its wettability and its unusual degree of comfort.