Procedure and device for automatic refractometric measurement of the degree of ametropia of a human eye
US4673265A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 5, 1986 |
| Grant date | Jun 16, 1987 |
| Priority date | — |
| Expiry date | Sep 5, 2006 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B3/103
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
This invention concerns a procedure and device for refractometric measurement of the degree of ametropia of a human eye. The device for this invention comprises a light-emitting source combined with a focusing lens, which produces an image of this source on the retina of the eye to be tested, a succession of test lenses which are placed in turn between the eye and the focussing lens, so that the optical axis of the relevant test lens coincides with the optical axis of the eye, and a light-intensity detector placed on this same axis at a fixed distance from the eye, together with means of identifying which test lens causes the detector to emit a signal of minimum intensity. The invention applies to instruments to measure visual acuity, more specifically in handicapped or very young patients.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.