Ophthalmic lens design with the optimization of the aspherical coefficients

An efficient approach for the designing of ophthalmic lenses, based on the optimization of the aspherical surface coefficients is presented. We show t hat five optimization constraints are enough to both reduce the aberrations and prevent the development of inflection points along the aspherical surf ace. In particular, we solve the inflection point problem by counting the s econd derivative of the sag with respect to the height of the aspherical su rface as one of the constraints. The design data indicate that nonconicoida l aspheric lenses can be made thinner and flatter than the equivalent spher ical or conicoidal lenses. The traditional damped least-squares methods are used and design results are given for both aspherical negative lenses and aspherical positive lenses, (C) 2000 Society of Photo-Optical Instrumentati on Engineers. [S0091-3286(00)02904-4].