Aspheric toric lens designs
US5796462A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 4, 1996 |
| Grant date | Aug 18, 1998 |
| Priority date | — |
| Expiry date | Sep 4, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02C2202/02
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
Aspheric toric lens designs are disclosed which reduce the number of cylindrical axis locations required for stock keeping units in inventory by aspherizing the toric surface thereof. The present invention pertains to ophthalmic lenses, and in particular to contact lenses such as soft hydrogel contact lenses, particularly designed to fit astigmatic patients who are either non-presbyopic or presbyopic. One of the front and back surfaces of the aspheric toric lens defines a spherical surface corresponding at least to the patient's basic distance prescription Rx. The other of the front and back surfaces defines an aspheric toric curve, wherein the toric surface is constructed with aspheric radii, such that the aspheric curve desensitizes axial misalignment of the toric curve by providing an enhanced depth-of-focus. When the aspheric toric surface is on the back surface of the lens, the spherical curve on the front surface of the lens can comprise a single spherical curve corresponding to the patient's basic distance prescription Rx. When the aspheric toric curve is on the front surface of the lens, the spherical curve on the back surface of the lens can comprise a multifocus concentri…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.