Progressive multifocal ophthalmic lens
US5272495A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 28, 1992 |
| Grant date | Dec 21, 1993 |
| Priority date | — |
| Expiry date | Oct 28, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02C7/061
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The lens has an aspherical surface having a zone for far vision, a zone for near vision, and between these two zones, a zone for intermediate vision, with a meridian curve along which the curvature of the surface varies progressively and which is inclined from top to bottom towards the nose side of the lens, at least in the intermediate zone. The portion of the meridian curve situated in the intermediate and near zones includes a segment at an angle .alpha. to the vertical where the value of .alpha. is an increasing function of the power addition A of the lens. In a horizontal and vertical system of coordinates, a point of the segment has an ordinate whose value is also an increasing function of the power addition A. At said point, the mean sphere value of the surface corresponds to a power addition lying in the range 0.8 to 0.92 times the nominal power addition of the lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.