Surgery – Truss – Pad
Patent
1991-05-21
1992-11-17
Cohen, Lee S.
Surgery
Truss
Pad
128691, A61B 502
Patent
active
051634376
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to an ophthalmic measuring device for measuring blood flow at a fundus to be subjected to ophthalmic examination.
When a laser beam is directed upon a tissue of a living body such as a fundus to illuminate thereon, the laser beam is scattered by particles which are present in the tissue of the living body, the scattered rays interfere with each other, causing a random pattern of the reflected scattered rays, i.e., a speckle pattern. On the other hand, as this speckle pattern varies momentarily with movement of blood cells as such particles in a blood capillary, by measuring change with time in light intensity at a certain point light signals are obtained including information concerning blood flow velocity, i.e., speckle signals. The present invention is directed to an ophthalmic measuring device for measuring a fundus with respect to blood flow velocity by utilizing the speckle pattern.
RELATED ART
Heretofore, there has been known an ophthalmic measuring device designed such that it illuminates a fundus to be examined with laser beam, photoelectrically detects the reflected light, and, based on the detected signals, measures blood flow velocity in a blood vessel at the fundus to be examined. A device of this type is arranged such that an illumination system and a detection system for a laser beam are incorporated into a conventional fundus camera, and, by means such as changing a direction of a visual axis of a subject while observing a fundus to be examined, a desired area of a blood vessel is illuminated with a laser beam to perform measurement.
Further, such a device is arranged such that the state of a fundus to be examined is photographed to record the state of the eye subjected to measurement.
However, as there are continual slight tremors of a collimation axis so-called flicks in an eye to be examined, an image of the fundus which an ophthalmic examiner observes always slightly oscillates. Consequently, it is difficult for such a conventional device to accurately identify the measured site at a moment when measurement has been conducted, so that there is adverse possibility of measurement at an area other than the intended site.
Further, in this conventional device, a photograph is taken after the measurement to record the area where measurement has been conducted. However, there is a problem in that because of the time lag between the recording and the moment of the measurement, it is difficult to record the exact measured site. Further, the conventional device separately requires the step of photographing besides the measurement, and therefore, the conventional devices are complicated in measuring procedure.
SUMMARY OF THE INVENTION
The present invention has been made in view of these problems. It is, therefore, an object of the present invention to provide an ophthalmic measuring device which is capable of recording an image of a fundus over which an image of an indication indicating a measured area is superimposed.
According to the present invention, there is provided an ophthalmic measuring device comprising:
an illumination system for illuminating a fundus to be examined,
a projection system for irradiating the predetermined area of the fundus to be examined with measuring a laser beam,
a detection means for detecting a reflected measuring laser beam from the irradiated area,
a storage means for storing signals obtained by means of the detection means, and
an arithmetic processing section for arithmetically processing state of blood flow in a blood vessel in the fundus on the basis of the stored signals;
Wherein the device indicates an area of the fundus to be examined, and a photograph of an image of the fundus, superimposed on an image of the indication, may be taken substantially simultaneously with the storage of signals into the storage means.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an optical view of a mydriatic fundus camera of the first embodiment of the present invention.
FIG. 2 is a plan view of a collimation.
FIG. 3
REFERENCES:
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patent: 4950070 (1990-08-01), Aizu et al.
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Fujii Hitoshi
Yokokura Takashi
Cohen Lee S.
Jastrzab J.
Topcon Corporation
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