Adaption of lensmeter optics for minimizing contact lens spherical aberration
US5198867A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 7, 1991 |
| Grant date | Mar 30, 1993 |
| Priority date | — |
| Expiry date | May 7, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/255
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Adaptions of lensmeter optical trains are disclosed for enabling the measurement of contact lenses without the interference of spherical aberration from the highly meniscus lens formats of contact lenses. A generic system of measurement of the contact lenses when off of the eye is introduced by having light incident to or passing from the suspect contact lenses at an approximate aplanatic condition of the contact lens. The approximate aplanatic condition is determined by taking the average power of the posterior and anterior surfaces of the contact lenses for the general population--approximately 8 mm, assuming an index of refraction of approximately 1.5--calculating the aplanatic condition for such a "surface," and having light incident on the lenses for the interrogation of the lenses approximate the aplanatic condition. Modification of four optical trains for contact lens measurement is disclosed, including a Badal type optical train, a typical focusing lensmeter, an automated lensmeter utilizing mask pattern with photodetector array, and a lens system with a matrix of light focusing lenses.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.