Compact subjective refractive instrument
US4179196A · kind A · utility
12Cited by
3References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 30, 1977 |
| Grant date | Dec 18, 1979 |
| Priority date | — |
| Expiry date | Sep 30, 1997 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B3/13
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A compact ophthalmic instrument for refraction of patient's eyes is obtained by substantial folding of the optical system. The optical system is folded in one location using a reflection means that moves to vary the location of a target image being viewed by a patient for identifying the spherical power of a corrective lens, if any, required by the patient. A second folded portion of the optical system contains a cylinder means for cylindrically varying the target image.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.