Multifocal ophthalmic lens
US6102544A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 29, 1999 |
| Grant date | Aug 15, 2000 |
| Priority date | — |
| Expiry date | Jun 29, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02C7/061
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In a multifocal ophthalmic lens comprising an aspherical surface having at every point thereon a mean sphere and a cylinder, a far vision region, a near vision region, and an intermediate vision region, the length of progression i.e. the length over which lens power varies by a set amount in different regions of the lens, is short. To avoid distortion at the periphery of the lens which this would otherwise occasion, the isosphere and isocylinder lines are distributed over the surface of the lens so as to ensure variations in sphere are not too sudden along a 20 mm radius circle centered on the geometric center of the lens and variations in cylinder on the surface of the lens inside this circle are also very small. The lens has an enlarged near vision region and progression is less perceptible to the wearer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.