Importance

Loading Importance Indicators...

Abstract

A progressive addition power lens having base and add spherical regions for providing refractive power correction for distance and near vision includes a central corridor characterized by a power curve expressed as a polynomial of at least the 11th degree. The surface contour of the intermediate corridor is defined by the surfaces of an ordered sequence of osculating spheres. The curvature of the surface of the intermediate region spreads away from the principal meridian in accordance with a spreading function having substantially circular level curves. Visual astigmatism is corrected over a substantial fraction of the base and add spheres by superposition of an aspheric function to the sag of the lens surface as defined by the polynomial and the spreading function.

Loading the Abstract Image...

First Claim