Fundus blood flowmeter
AssigneeCanon Kabushiki Kaisha
InventorShinya Tanaka
Life of this patent
Estimating the term…
Abstract
When a blood flow velocity in a blood vessel on the fundus is to be measured, a cofocal aperture is inserted to eliminate the influence of scattered light from regions other than a measurement region, thereby obtaining a measurement result with a high S/N. When a blood flow velocity in the papilla is to be measured, a light shielding aperture is inserted in place of the cofocal aperture to eliminate a regularly reflected component from the papilla, thereby obtaining a measurement result with a high S/N. A fundus blood flowmeter can select one of the two measuring modes and can switch the above apertures in accordance with each mode.
Claims4
An ophthalmologic measurement apparatus comprising:
- irradiation means for irradiating a fundus of an eye to be examined with coherent blood flow measurement beam;
- detection means for detecting scattered light of the measurement beam from the fundus;
- arithmetic means for calculating a blood flow velocity on the basis of a signal from said detection means;
- and
- a light shielding aperture for covering a region irradiated with the measurement beam at a position, substantially conjugate to the fundus, of said detection means.
An ophthalmologic measurement apparatus comprising:
- irradiation means for irradiating a fundus of an eye to be examined with coherent measurement beam;
- detection means for detecting scattered light of the blood flow measurement light from the fundus;
- arithmetic means for calculating a blood flow velocity on the basis of a signal from said detection means;
- a light shielding aperture for covering a region irradiated with the measurement beam at a position, substantially conjugate to the fundus, of said detection means,
- a cofocal aperture for shielding light other than scattered light from the irradiated region irradiated with the measurement beam at the position substantially conjugate to the fundus;
- and
- mode switching means for switching between a first measuring mode of measuring a blood flow velocity in an optical nerve head and a second measuring mode of measuring a blood flow velocity in a blood vessel on the fundus,
- wherein said light shielding aperture and said cofocal aperture are switched in accordance with switching by said mode switching means.
Dependencies are inferred from the claim text.