Abstract

Optical design of a multifocal intraocular lens is limited to the simultaneous vision principle which features two or more lens powers within the pupillary area at the same time. The principle is applied as well to contact lenses though some design requirements are different due to contact lens fitting constrains, wearer's residual accommodation and IOL's safety considerations. The simultaneous principle can be divided into two basic designs: Bifocal lens specified by two levels of diopter powers and Progressive Aspheric with continuous range of diopter powers (Charman and Saunders, 1990; Morrison, 1986; Freeman and Stones, 1987; Charm et al., 1987; Charman and Walsh, 1988; Evans and Morrison, 1983; Evans, 1983; Charman and Walsh, 1986; Erickson et al., 1988).

© 1992 Optical Society of America