Optics: eye examining – vision testing and correcting – Eye examining or testing instrument – Objective type
Reexamination Certificate
1999-02-26
2001-02-20
Manuel, George (Department: 3737)
Optics: eye examining, vision testing and correcting
Eye examining or testing instrument
Objective type
Reexamination Certificate
active
06190011
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ophthalmic apparatus which obtains characteristics of an eye to be examined and a method for storing ophthalmic information therefor.
2. Description of Related Art
It is known for apparatuses which obtain characteristics of the eye to be examined, such as a corneal shape analyzing apparatus, a sectional view analyzing apparatus for analyzing a degree of opacities of a cornea or a crystalline lens and a shape of each part of an anterior part of the eye based on an image of a sectional view thereof.
For example, it is known for the corneal shape analyzing apparatus which projects a placido ring target onto a cornea, then photographing an image of the target by using a photographing camera, thereby calculating a curvature distribution over a wide range of the cornea, based on the obtained image data of the eye. The curvature distribution is visualized as the topography.
On calculating a corneal curvature, firstly, a plurality of standard balls having a known curvature are photographed whereby the image data are obtained. A calibration data is obtained based on the image data and the curvature of respective balls. Thereby, based on both of the calibration data and the image data of the eye, an analyzed result converted to an absolute value is calculated. The calibration data is intrinsic for the apparatus, therefore it is not shared by the same model apparatus due to the intrinsic difference. In the case of above mentioned corneal shape analyzing apparatus, the following are listed as the intrinsic difference: dispersion, displacement or the like of a placido ring, its mounting position and a photographing camera provided for a photographing optical system. The calibration data is used for the purpose that the analyzed result may not involve the intrinsic difference. The calibration data is usually stored in a memory of the apparatus in the form of a calibration data file.
Certainly, although the calibration data is intrinsic for the apparatus, if the obtained and analyzed result is stored, and the topography is re-displayed on another apparatus, then there is no difference between contents of displays.
In contrast, an apparatus which has a re-analysis function is known. The function is such as to store a raw image data of an eye which is obtained by using the photographing camera, then calling the raw image data and obtaining an analyzed result based on a calibration data.
However, referring to such apparatus that use calibration data as described above, there are problems as follows.
Firstly, such apparatus that stores only an analyzed result converted to an absolute value can not utilized for a new analyzing method. For example, in the case of examining variation of the analyzed result by way of obtaining results at a fixed period of time extending over a long period of time in order to carry out a historical observation, even if an operator makes an effort to interrupt the analysis and to adopt a new analyzing method, the operator can not use the new analyzing method with respect to such data as obtained in the past.
There is such possibility that an apparatus which has a function for storing a raw image data may adopt a new analyzing method by way of calling the raw image data, provided the identical apparatus is used. If the raw image data, obtained by using another apparatus, is analyzed by mistake, then reliability of the analyzed result is deteriorated due to the different calibration data. In addition, even if the identical apparatus is used, once the calibration data is changed by way of re-calibrating the apparatus, the re-analyzed result of the raw image data, obtained before or after calibration, can not achieve high accuracy.
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 ophthalmic apparatus which can ensure the accuracy of the analyzed result with respect to each raw data. The raw data may be such as to be obtained by using different apparatus, or as to be obtained before and after re-calibration. In the specification, a raw data may be a raw data literally, a part of which may undergo image processing.
Another object of the present invention is to provide a method for storing an ophthalmic information therefor such as the raw data.
To achieve the objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, an ophthalmic apparatus comprises detecting device for detecting information of an eye to be examined, first memory which is capable of storing a plurality of calibration information which is used for calibrating a result detected by the detecting device, and second memory for storing the eye information, and an associating device for associating the calibration information at the time of detection with the eye information which is detected by the detecting device.
The ophthalmic apparatus of the present invention may further comprise input device for inputting an analyzing program, and analyzing device for calculating or analyzing characteristics of the eye by using the eye information and the associated calibration information, based on the inputted analyzing program.
According to the present invention, the accuracy and the reliability of the analyzed result with respect to both of each raw data obtained by a different apparatus and each raw data obtained before and after re-calibration may be ensured.
Another aspect of the present invention is a method for storing an ophthalmic information utilized for an ophthalmic apparatus, the method comprising the steps of (1) detecting information of an eye to be examined, (2) obtaining calibration information which is used for calibrating a result detected by the detecting step, a plurality of the calibration information being capable of being stored, and (3) storing the eye information detected by the detecting step, and associating the calibration information at the time of detection eye information.
Further another aspect of the present invention is a, ophthalmic apparatus that comprises a projecting device for projecting a target pattern for measurement onto a cornea of an eye to be examined and a standard ball, photographing device for photographing an image of the target pattern for measurement, the image being formed onto the cornea and standard ball, calculating means for calculating calibration data based on image data and a curvature of the standard ball which is photographed by the photographing device, first memory which is capable of storing a plurality of the calibration data obtained by the calculating device, and second memory for storing image data of the eye, and an associating device for associating the calibration data at the time of photographing with the image data of the eye which is photographed by the photographing device.
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Finnegan Henderson Farabow Garrett & Dunner
Manuel George
Nidek Co. Ltd.
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