Abstract: 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.

Abstract: The inner surface of a semi-scleral contact lens is shaped relative to the topography of an individual eyeball to achieve central contact and edge contact with tearfilm clearance therebetween. The lens has improved centering properties. The lens includes an optical zone which is the spherical equivalent of the radius of curvature of the cornea at its optical centerline and the corneal dimensional diameter. The optical zone has a sagittal depth which is dependent on the topography of the cornea. The lens also includes a conoid section which is tangent to the edge of the optical zone and which extends from the edge of the optical zone to a selected point over the limbus. A peripheral curve having an individual radius of curvature extends from the selected point to the edge of the lens.

Abstract: A contact lens has an improved interior surface which includes an optical zone and peripheral zone. The optical zone has a radius of curvature similar to that of the cornea of the eye to be fitted. The peripheral zone defines an arc which is substantially tangent to the optical zone at its edge and which intersects the curved line defined by the selected diameter of the lens at the selected sagittal depth. The lens can be formed from a hard or flexible material and can be made by a lathe turning or by molding.

Abstract: This is a method and apparatus for machining a flexible silicone contact lens which utilizes a moving, flexible abrasive tape bearing against the rotating lens to accomplish the desired result. The tape travels in a transverse direction across the lens and may be oscillated to provide a more uniform finish.