Apparatus for measuring the refractive power of the eye
US4376573A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 18, 1980 |
| Grant date | Mar 15, 1983 |
| Priority date | — |
| Expiry date | Mar 18, 2000 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B3/103
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
In an apparatus having a ray generator for directing measuring rays through a first optical path, a light-receiving portion for receiving the measuring rays reflected by the eye fundus through a second optical path, and a uniting device for uniting the first and second optical paths to form a third optical path, and also having movable lens groups in each of the first and second optical paths or a movable lens group in the third optical path, and wherein the movable lens groups or group is moved along the optical path to measure the refractive power of the eye from signals corresponding to the positions of the movable lens groups or group and the signal of the light-receiving portion, the movable lens groups or group is made into an afocal system to prevent the dimensions of the pupil from being varied and a collimator for collimating the principal rays is fixedly disposed on that side of the movable lens groups or group which is adjacent to the eye to be examined.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.