Patent ID: 7625085
Filing Date: 2009-12-01
Classification: G02C

Abstract:
1. An ophthalmic lens, comprising: a posterior surface having a central optic zone, a peripheral zone, and a blending zone therebetween; the central zone being asphero-toric and defined by the equation: where z, x, and y are coordinates relative to respective z-, x-, and y-axes, cx=1/apex radius x, cy=1/apex radius y, and kx and ky are conic constants relative to the respective x- and y-axes, where −2.0<kx<0.0 and −2.0<ky<0.0; the peripheral zone being aspheric, rotationally symmetrical about the z-axis, and defined by the equation: where z and x are coordinates relative to the respective z- and x-axes, cx=1/apex radius x, and kx is the conic constant, where −2.0<kx<0.0; and the blending zone forming a smoothened transition between the asphero-toric central zone and the aspheric peripheral zone, the blending zone described at least in part by spline curves, wherein along a cylindrical meridian and a spherical meridian the slope changes of the spline curves in the blending zone are opposite and about the same in magnitude, and along a meridian halfway between the cylindrical and spherical meridians in the blending zone a continuation of the central zone generally matches a continuation of the peripheral zone.