Method for measuring the rotation of an assymetric contact lens and lenses for practicing the method
US4976533A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1988 |
| Grant date | Dec 11, 1990 |
| Priority date | — |
| Expiry date | Jun 7, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02C7/048
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A contact lens comprising a corneal section, a vertical axis, and a shape adapted to maintain the lens at an intended orientation. The improvement comprises either a visible horizontal line segment located in the corneal section perpendicular to the vertical axis and/or three visible radial line segments in the corneal section, the first of the line segments located on the vertical axis, and the second and third segments located on either side of the first segment such that the extension of the segments would pass through a geometric center of the corneal section forming two 20.degree. angles. The lens is useful for measuring the rotation of an assymetric lens. Methods for measuring lens rotation using the invention lenses are also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.