Ophthalmological measurement method and apparatus
US5129400A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 9, 1990 |
| Grant date | Jul 14, 1992 |
| Priority date | — |
| Expiry date | Apr 9, 2010 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B3/1225
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
In an ophthalmological measurement method and apparatus, a laser beam of predetermined diameter is projected to the eye fundus and movement of a speckle pattern formed by light scattered by blood cells in blood vessel is detected by a photosensor as fluctuation in speckle light intensity to produce a speckle signal. The speckle light intensity will fluctuate more rapidly with a smaller output from the photosensor when cell velocities are high, while a low cell travel speed will decrease the lowering of the output therefrom. The speckle signal thus mirrors the travel speed of the blood cells in the eye tissues. The differences in the speckle signal are used to identify the blood vessel for automatic tracking of the blood vessel or for measurement of its diameter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.