Abstract: A rotationally symmetric contact lens has a reservoir formed centrally on the posterior surface thereof to provide an additional optical power of up to 1.51 diopters. The reservoir may be spherically or aspherically shaped.

Abstract: Dies for posteriors and anterior curves. A spherical surface is formed in the end of a body member, the side walls of which are compressed to change the spherical surface geometry to toric shape. The side wall is cylindrical and provided with two elongated slots which define two opposite ribs. A bolt passing through the ribs is tightened to provide the compressive forces.

Abstract: A bifocal contact lens has a distant-vision portion of a diameter between 3 and 5 mm either located in the center of the lens or offset about 2 mm above the center. The anterior surface of the lens is cast in an injection molding machine from a working die which itself is made from a master-die composed of two pieces of steel, a plug portion being tightly fitted in an aperture in the carrier portion so that the boundary of the different prescription curvatures of the plug and carrier portion will meet as closely as possible. The plug portion is shrink-fit inside the carrier portion. No further finishing procedures are necessary after casting the bifocal lens in one piece from the working dies, and the working dies are so cheap to cast that they may be melted down after one or a few uses to make new working dies from the steel master-dies.