Method and apparatus for measuring retinal blood flow
US4346991A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 22, 1980 |
| Grant date | Aug 31, 1982 |
| Priority date | — |
| Expiry date | Oct 22, 2000 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/0261
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
Blood flow in a retinal blood vessel is measured by detecting the doppler shift imparted to two laser beams intersecting on a portion of the retinal vessel. Twin beams of laser radiation are directed along an optical path into an eye and scattered radiation returned along the path into two photo-multipliers. The twin beams are passed through a beam rotator so that the plane containing them can be aligned along the retinal vessel under measurement. A local oscillator signal for homodying with the doppler shifted laser radiation is obtained from reflections from the eye itself or a separate reflector. This reflector can be moved to impart a frequency shift to the local oscillator signal to remove ambiguities in the doppler measurements. Automatic tracking of small eye movements is provided by a beam deflector and servo motor controlled by a detector. Width of the retinal vessel under measurement is obtained by deflecting returning scattered laser radiation and determining the width of the detector signal change.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.