Patent ID: 8038294

Claim:
A method of manufacturing a contact lens including the steps of: providing an optical zone in a center part of the lens; providing a peripheral zone surrounding the optical zone; providing a rear surface optical zone with a concave shape that substantially matches a surface profile of a cornea while providing a front surface optical zone with a convex shape adapted to provide a required spherical diopter power and geometrical center thickness; and designing a face of either the front surface optical zone or the rear surface optical zone so as to impart thereto cylindrical power and axial angle necessary for a toric surface; comprising further steps of: establishing on the rear surface optical zone a base rear surface profile of concave shape that substantially matches a surface profile of the cornea and a geometrical center thickness of the contact lens; establishing on the front surface optical zone a base front surface profile of convex shape in view of the base rear surface profile and to the required spherical diopter power and geometrical center thickness; selecting a number of angular directions (θ) about the geometrical center axis of the optical zone, and establishing a radius of curvature of the rear surface optical zone in each of the angular directions (θ) so as to give a desired cylindrical power and cylindrical axial angle; establishing at least one desired junction thickness in a joint zone that connects the optical zone with the peripheral zone at desired multiple sites along multiple diametrical axes about the geometrical center axis of the optical zone, and deriving multiple diametrical positions of the joint zone that will impart the junction thickness along multiple diametrical axes about the geometrical center axis of the optical zone; and establishing positions of the joint zone between the multiple diametrical positions in the circumferential direction through an interpolation process so as to derive along the entire circumference of the lens a radius of the optical zone that satisfies the desired junction thickness.