Generalization of the Tscherning theory: optimization of aspheric ophthalmic lenses

The perfect single vision ophthalmic lens should be free from oblique astigmatism, mean oblique error, distortion and chromatism. At the same time, it should be aesthetic and comfortable. By means of third-order theory, we show that T scherning ellipses can be considered to correspond merely to the particular case in which the lens surface is spherical in the three-dimensional space defined by the conic constant epsilon, the power of the first surface D1, and the back vertex power D. Consideration is given to the best way of building a merit function for final optimization with a classical ray tracing optimization program on a computer.