Eyeglass wearers prefer to have their lenses made as thin, light weight, and distortion free as possible. A thinner lens may be achieved by simply making the front curve of the lens flatter. For example, an Rx is ground with conventional spherical lenses on a +6.00 D base curve. If that same prescription is ground on a +4 .00 base instead, it would result in a thinner lens. The optics, however, would be significantly compromised. The benefit of a lens designed with an aspheric surface is that it allows the finished lens to be made flatter, thinner, lighter, with less magnification— and without compromising the optics.

This course surveys the various lens aberrations and historically traces the efforts that have been made to minimize them. It then goes on to cover the subjects of fitting, dispensing, and identifying aspheric lenses.