Patent ID: 8449111

Claim:
A method for manufacturing a prescription lens fitted for an eyeglass frame, comprising the steps of: (a) obtaining information of a prescription lens from a prescription and information of a frame to accommodate the prescription lens, wherein the information of the prescription lens comprises a lens power, an optical zone and a spherical front base curve, and wherein the information of the frame comprises a frame curve characterized with an angle and tilt of the frame; (b) calculating an optimum size of the optical zone as well as the maximum lens thickness of the prescription lens at the optical zone according to the information of the prescription lens and the information of the frame; (c) selecting a lens according to the calculated maximum lens thickness at the optical zone, the information of the prescription lens and the information of the frame; and (d) processing the selected lens so as to obtain the prescription lens having: a spherical front lens surface with a front base curve configured to match a curve profile of the frame; and a rear lens surface curved such that the lens has a central optical zone, an annular intermediate zone surrounding the central optical zone, and an annular edge zone surrounding the intermediate zone, wherein the rear lens surface in the central optical zone has a curvature such that the central optical zone of the lens has a lens power substantially equal to a prescribed lens power for a wearer of the lens, the rear lens surface in the edge zone has a substantially flat profile in a direct substantially perpendicular to an optical axis of the lens, and the rear lens surface in the intermediate zone has a curvature that smoothly bridges the curvature of the rear lens surface in the central optical zone and the flat profile of the rear lens surface in the edge zone, and wherein the lens has a substantially uniform edge thickness around a circumference of the lens, the edge thickness being thinner than a maximum thickness of the lens in the central optical zone.