Patent ID: 6467903
Filing Date: 2002-10-22
Classification: G02C

Abstract:
A contact lens, comprising:a contact lens body having a generally spherical base curvature with a convex anterior. face, a concave posterior face, and a peripheral edge therebetween with a peripheral zone being defined adjacent the peripheral edge of the anterior face that is tapered thinner toward the peripheral edge of the lens, the body having a thickness between the anterior face and the posterior face and being non-axi-symmetric so as to define a superior edge and an inferior edge, with a vertical meridian being defined from the superior edge toward the inferior edge and a horizontal meridian being defined perpendicular thereto; a plurality of zones on the anterior face, including an inner zone circumscribed by the peripheral zone, and an optic zone defined generally in the middle of the inner zone, wherein the inner zone includes a ballast portion and the thickness increases parallel to the vertical meridian from the superior edge toward the inferior edge in at least the ballast portion of the inner zone; wherein the inner zone comprises a superior portion between the optic zone and the superior extent of the inner zone, an inferior portion between the optic zone and the inferior extent of the inner zone, and an intermediate portion between the superior and inferior portions; and the ballast portion is defined within one or more of the superior, intermediate, and inferior portions and has a series of consecutive horizontal cross-sections exclusive of the peripheral zone and optic zone spanning a distance along the vertical meridian of at least 20% of a smallest dimension of the superior, intermediate, and inferior portions as measured along the vertical meridian, wherein each horizontal cross-section has a substantially uniform thickness not varying by more than about 30 &mgr;m or 20%, whichever is greater in absolute terms.