Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
1998-04-02
2001-11-27
Smith, Ruth S. (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
C600S504000, C351S206000, C351S209000, C351S221000
Reexamination Certificate
active
06324420
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fundus blood vessel monitoring or observing apparatus for measuring a blood-flow velocity or speed in the blood vessel in an eye fundus.
2. Description of the Related Art
Hitherto, there has been known a laser doppler fundus blood-flow meter or velocimeter as an apparatus for tracking of a blood vessel in an eye fundus. In the case of the fundus blood-flow meter, it is important that a blood vessel, through which a blood flow having a blood flow velocity to be measured flows, is selected, that the tracking of the selected blood vessel is performed, and that the selected blood vessel is irradiated, with measurement beams during the measurement of the blood flow velocity. Thus, there has been proposed a system which is provided with a detection mechanism for detecting a nictitation (or blink) of an eye to be examined. This system is adapted so that the tracking of the blood vessel is temporarily interrupted when nictitation of the eye occurs during the measurement of the blood flow velocity, and so that the tracking of the blood vessel is resumed by calculating a restart position when nictitation of the eye is finished and the system is brought into a condition in which the tracking thereof is enable to be performed. Further, there has been known another fundus blood-flow meter adapted so that the tracking of a blood vessel ceases when detecting an abnormality in a value represented by a tracking-position signal.
However, the aforementioned conventional system that is adapted to interrupt the tracking of a blood vessel has the drawback that, when resuming the tracking thereof, it cannot determine whether or not the tracking is performed on the same blood vessel as before the interruption of the tracking. Further, the blood flow meter adapted to detect an abnormality in a tracking-position signal has the following defect. Namely, in the case where another (adjacent) blood vessel is present in the vicinity of a blood vessel on which the tracking is performed, according to the conditions of eyelashes, tears, and fixation (of an eye), no abnormality is detected in the tracking position signal, so that it is erroneously determined that the measurement of a blood-flow velocity is normally finished.
SUMMARY OF THE INVENTION
The present invention aims at eliminating the aforementioned drawback and defect of the conventional art.
To achieve the foregoing object, in accordance with the present invention, there is provided an eye fundus blood-vessel observing apparatus having tracking means for performing tracking of a blood vessel in an eye fundus, which further comprises: blood-vessel image recording means for recording images of a plurality of blood vessels in an eye fundus obtained during tracking; blood-vessel-diameter calculating means for calculating blood-vessel diameters from the images of the aforesaid plurality of blood vessels; blood-vessel-diameter recording means for recording the calculated blood-vessel diameters; and computing means for computing a variation in the plural calculated blood vessel diameters.
Accordance to one aspect, the present invention relates to a blood-vessel tracking apparatus comprising an illumination light source for emitting light and illuminating a blood vessel with the light; a light-receiving sensor for receiving a blood-vessel image comprising light from the illumination light source reflected by the blood vessel, optical-path changing means for changing an optical path of the light emitted from the illumination light source, calculation means for calculating the blood-vessel diameter of the illuminated blood vessel based on an output of the light-receiving sensor, a plurality of times, and measurement means for measuring a change in blood vessel diameter based on the calculating performed by the calculating means. The apparatus can also comprise comparison means for comparing the change in blood vessel diameter, obtained by the measuring means, with a predetermined value. In addition, the apparatus can also comprise display means for displaying a result of the comparison made by the comparison means. Further, the device can include a detection sensor for detecting a nictitation of an eye to be examined. The calculation means in this embodiment calculates the blood vessel diameter before the nictitation detected by the detection sensor is performed and calculates the blood vessel diameter after the nictitation detected by the detection sensor is performed.
REFERENCES:
patent: 4830483 (1989-05-01), Kohayakawa et al.
patent: 4866243 (1989-09-01), Sakane et al.
patent: 5129400 (1992-07-01), Makino et al.
patent: 5270749 (1993-12-01), Okumura
patent: 5500696 (1996-03-01), Masuda et al.
patent: 5630179 (1997-05-01), Kishida
patent: 5751396 (1998-05-01), Masuda et al.
patent: 5844658 (1998-12-01), Kishida et al.
patent: 5976096 (1999-11-01), Shimizu et al.
Iwanaga Tomoyuki
Kishida Nobuyoshi
Numajiri Yasuyuki
Okumura Toshiaki
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Smith Ruth S.
LandOfFree
Blood vessel tracking apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Blood vessel tracking apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Blood vessel tracking apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2618526