Multifocal contact lens
US5691797A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 19, 1996 |
| Grant date | Nov 25, 1997 |
| Priority date | — |
| Expiry date | Jan 19, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02C7/043
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A multifocal contact lens customized for a patient has an anterior side with a power curve defined in part by (i) a central spheric aspheric surface, (ii) an inner annular spheric surface contiguous with the central aspheric surface, (iii) a second annular spheric surface contiguous along a radially inner periphery with the inner annular spheric surface, and (iv) an outer annular spheric surface contiguous along a radially inner periphery with the second annular spheric surface. Each of the annular spheric surfaces is concentric or coaxial with the central aspheric surface. The central aspheric surface corresponds to a distance vision correction zone. The inner annular spheric surface is an spheric surface corresponding to an intermediate vision correction zone. The second annular spheric surface corresponds to a near vision correction zone, and the outer annular spheric surface corresponds to a distant vision correction zone.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.