Toric single vision, spherical or aspheric bifocal, multifocal or progressive contact lenses and method of manufacturing
US5406341A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 23, 1992 |
| Grant date | Apr 11, 1995 |
| Priority date | — |
| Expiry date | Nov 23, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02C2202/20
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
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. 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. 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 designati…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.