Ophthalmic diagnostic method and apparatus
US4938584A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 9, 1989 |
| Grant date | Jul 3, 1990 |
| Priority date | — |
| Expiry date | Jun 9, 2009 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B3/1005
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
An ophthalmic diagnostic method and apparatus measures the distance between the corneal surface and the fundus of an eye being examined by projecting a beam of coherent light at the eye and varying the wavelength of the coherent light while observing differences between the optical paths of two light waves reflected by the cornea and the eye fundus. The differences are based on the length of the optical axis of the eye and observed as a phase difference between the two light waves. The length of the optical axis of the eye being examined can be measured from the amount of change in the measured phase difference corresponding to the variation in wavelength, enabling the length of the optical axis of the eye to be measured without mechanical control.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.