Aspherical surfaces used to minimize oblique astigmatic error, power error, and distortion of some high positive and negative power ophthalmic lenses.
Ophthalmic lenses are generally corrected for oblique astigmatic error or optimized to balance astigmatic and power errors. Distortion is not corrected in these lenses. The nature of the aspheric surface needed to minimize astigmatic error, power error, and distortion in -20-, -14-, and +14-diopter lenses was investigated using the ACCOS V lens design programs. The best correction for the -20- and -14-diopter lenses was obtained by allowing their front and rear surfaces to become deformed ellipsoids of revolution about the minor axis. The +14-diopter front and rear lens surfaces became deformed ellipsoids of revolution about the major and minor axes, respectively. Performance data over the full field of view, corresponding to +/-30 degrees of eye rotation, are given.
Katz
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