Importance

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Abstract

A method for producing a bifocal contact lens comprising, in combination, the steps of generating a first, concave surface on a first side of a lens blank eccentrically mounted in concave surface cutting means, wherein the center of curvature of the concave surface lies on an axis offset from the optical center axis of the lens blank by a prism offset distance; generating a second, convex surface on the second side of the lens blank, wherein the center of curvature of the convex surface lies on the optical center axis of the lens blank; generating a third, convex surface on the second side of the lens blank eccentrically mounted in convex surface cutting means, wherein the center of curvature of the third, convex surface is coaxial with the second, convex surface; trimming the first, concave surface to form a fourth, concave surface on the first side of the lens blank the curvature of the fourth surface corresponding to the base curve; and finishing the lens by known methods. If desired, the posterior optical zone may be decentered by eccentrically mounting the lens blank in edge curve cutting means prior to cutting the edge curves.

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First Claim