Bifocal contact lens with toric transition
US6176579A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 7, 1999 |
| Grant date | Jan 23, 2001 |
| Priority date | — |
| Expiry date | Jul 7, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02C7/042
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Bifocal contact lenses are lenses with two zones having different optical powers, or more than two zones in which case they are also called multifocal lenses. Concentric bifocal contact lenses have two or more annular power zones with a connection that presents optical problems. These optical problems are solved in my invention by connecting the spherical power zones for far and near viewing by a unique toric transition zone. The toric transition zone provides a smooth and continuous slope that will not produce visual jump where it joins with the power zones. There is only one toric curve with the correct properties for each pair of bifocal power zone parameters, consisting of the power zone radii and widths.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.