Method of manufacturing toric single vision, spherical or aspheric

Abstract

A method for making a finished aspheric single vision, spherical or aspheric bifocal, multifocal or progressive addition contact lens includes the step of fitting a patient requiring a near correction with a single vision spherical or aspheric contact lens for optimal distance vision and comfortable fit. If desired, the patient is then over-refracted to determine the required near correction to be embodied in the contact lens. A portion of the optic corresponding to the center location of the pupil is marked on the convex side of the optic to form an optical preform. In some instances, the lens may not stabilize on the cornea to a suitable degree. Thus, it is often desirable to stabilize the contact lens, either prior to placing the lens on the patient or after rotation is observed on the cornea of the patent. Observation of rotation on the patient's cornea is enhanced by means of the mark that is used to designate the center of the patient's pupil. The optical preform is removed from the eye of the patient and the concave side of the optical preform is marked at a position corresponding to the mark on the convex side that denotes the center of the pupil. The mark disposed on the convex side of the optical preform is removed. A specified volume of polymerizable resin is placed in a mold embodying the required correction, which includes an add power zone so that the resin fills the intervening space between the mold and the optical preform. The add power zone is aligned on the optical preform to a predetermined position with respect to the mark on the optical preform designating the center of the pupil. The resin is then polymerized the optical preform is demolded to obtain the finished contact lens having the required correction.