Design criteria for a high plus soft contact lens that fulfills the oxygen needs of the cornea in the aphakic eye.

A soft contact lens can be designed that will satisfy simultaneously in an optimum manner the optical, mechanical, and physiological requirements of the aphakic eye. The relationship fo water content to both refractive index and oxygen transmissibility allows incorporation of the latter quantity into the equation for back vertex power. Starting with the patient's requirement of back vertex power, base curve, and optic zone diameter a contact lens is designed to be mechanically strong, by having minimum water content, and to supply sufficient oxygen for the cornea's needs.