Patent ID: 7121664

Claim:
A method of designing a spectacle lens having a front surface and a back surface, at least one of the front and back surfaces is formed as a rotationally asymmetrical aspherical surface, comprising the steps of: selecting a plurality of cross-sections of the spectacle lens respectively defined in a plurality of planes each of which includes a reference axis passing through the front and back surfaces at a point substantially equal to a center of an outer diameter of the spectacle lens, each of the plurality of cross-sections having one side coinciding with the reference axis; designing each of shapes of the plurality of cross-sections so that predetermined optical performance is optimized for each of the shapes of the plurality of cross-sections; and interpolating a characteristic amount regarding intermediate points on the rotationally asymmetrical aspherical surface between the shapes of the plurality of cross-sections using a characteristic amount of each of the shapes of the plurality of cross-sections.