Objective refractor
US5157427A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 16, 1990 |
| Grant date | Oct 20, 1992 |
| Priority date | — |
| Expiry date | Apr 16, 2010 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B3/103
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
An objective refractor having no moving parts is disclosed. The refractor, which can be either a hand held or table mounted instrument, includes a reference array and an interrogating array projected onto the eye fundus. The reference array is projected from light sources and the interrogating array is projected to light detectors. Both the reference array and the interrogating array are projected onto the fundus of the eye through preselected spaced apart regions of the eye lens. The movement of the reference array with respect to the interrogating array is observed. By the expedient of making at least two sequential observations utilizing at least three separate regions of the eye lens, the amount of relative pattern displacements can be reduced to a requisite optical prescription for the eye.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.