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 that five optimization constraints are enough to both reduce the aberrations and prevent the development of inflection points along the aspherical surface. In particular, we solve the inflection point problem by counting the second derivative of the sag with respect to the height of the aspherical surface as one of the constraints. The design data indicate that nonconicoidal aspheric lenses can be made thinner and flatter than the equivalent spherical 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.