CONTACT LENS HAVING PRESELECTED MASS

摘要

A contact lens of a preselected mass has an optical zone and at least one peripheral zone. The optical zone has a shape and thickness sufficient to result in a desired optical correction. At least one peripheral zone has a thickness selected to correspond with that of the optical zone so as to result in the lens having the preselected mass. In a preferred embodiment, the lens has an optical zone, an intermediate peripheral zone and an outer peripheral zone. The intermediate peripheral zone has a thickness which is varied to correspond with that of the optical zone and the outer peripheral zone has parallel carriers. The preferred embodiment may have an inner surface shaped so that the radius of curvature of the optical zone is substantially equal to that of the cornea at its optical centerline, the peripheral curves have centers of curvature offset from the centerline of the optical zone and the curves are tangent where they meet. Such an inner curve can result in tearfilm clearance from the edge of the lens to the center of the optical zone. The lens preferably has a low mass and is made from a silicone rubber. The invention includes a set of at least two such lenses having the same mass and diameter but differing optical correction.