Optics: eye examining – vision testing and correcting – Eye examining or testing instrument – Objective type
Reexamination Certificate
2000-02-24
2001-03-27
Manuel, George (Department: 3737)
Optics: eye examining, vision testing and correcting
Eye examining or testing instrument
Objective type
Reexamination Certificate
active
06206523
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an eye refractive power measurement apparatus for measuring refractive power of an eye to be examined.
2. Description of Related Art
Widely known is an eye refractive power measurement apparatus comprises a measuring optical system which projects measurement light onto a fundus of an eye to be examined and receives the light reflected therefrom with a photodetector in order to obtain the refractive power based on output signals from the photodetector. In the measurement with this apparatus, a measurement error often occurs due to partial opacity of ocular media (crystalline lens and the like) caused by cataract and the like.
In order to carry out measurement on this type of the eye that often causes a measurement error, a measurement optical system needs to be re-aligned at such a position to avoid an opaque area and the like, a part that interferes with the measurement while observing the eye to be examined.
However, it is difficult especially for an examiner who is unfamiliar with the examination to find such an appropriate position.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above circumstances and has an object to overcome the above problems and to provide an eye refractive power measurement apparatus with which an examiner can carry out measurement easily in such a position to avoid a part such as opacity and the like.
Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, an eye refractive power measurement apparatus for measuring refractive power of an eye to be examined, the apparatus comprises a measurement unit including a projecting optical system for projecting measurement light onto a fundus of the eye, and a detecting optical system for receiving the reflected light of the measurement light reflected from the fundus, an arithmetic unit for obtaining the refractive power based on an output signal from the photodetector, a moving unit for moving the measurement unit relative to the eye, and a control unit for detecting an interfering part that interferes with the reflected light passing through the eye based on the output signal from the photodetector and for driving and controlling the moving unit based on the detected results.
In another aspect of the present invention, an eye refractive power measurement apparatus for measuring refractive power of an eye to be examined, the apparatus comprises measurement means for projecting measurement light onto a fundus of the eye, and thereby receiving the reflected light of the measurement light reflected from the fundus with a photodetector, arithmetic means for obtaining the refractive power based on an output signal from the photodetector, moving means for moves the measurement means relative to the eye, detecting means for detecting an interfering part that interferes with the reflected light passing through the eye based on the output signal from the photodetector, and control means for driving and controlling the moving means based on the detected results obtained by the detecting means.
REFERENCES:
patent: 5751396 (1998-05-01), Masuda et al.
patent: 5907388 (1999-05-01), Fujieda
patent: 3-128034 (1991-05-01), None
patent: 6-245909 (1994-09-01), None
patent: 7-222716 (1995-08-01), None
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Manuel George
Nidek Co. Ltd.
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