JPH07171102A - Optometry device - Google Patents

Abstract

PURPOSE:To extinguish an unnecessary lighting light source at a prescribed optical measurement, and facilitate the measuring treatment. CONSTITUTION:An objective lens 1, a light dividing member 2, a diaphragm 3, and a two-dimensional optical sensor 4 are arranged in the front of a testee eye E successively from the eye E side along an optical axis 01. A ring light source 5 is arranged around the objective lens 1. A light source 6, an alignment target 7, a lens 8, the light dividing member 2, a lens 9, and a television camera 10 are successively arranged on an optical axis 02 crossing the optical axis 01 at a right angle and passing the light dividing member 2, and the output of the television camera 10 is connected to a television monitor 11. When the cornea diameter is measured, the ring light source 5 and the light source 6 are extinguished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optometry apparatus which is used in an ophthalmology clinic or the like and which performs an optical measurement on an eye to be examined.

[0002]

2. Description of the Related Art In an optometry apparatus, an optical measurement may be performed on an eye to be examined from an image of a television camera.

[0003]

However, if illumination unrelated to the measurement is applied to the anterior segment at that time, it may enter the image as noise, and the measurement process may become difficult.

It is an object of the present invention to provide an optometry apparatus that reduces the influence of ambient light during measurement.

[0005]

A specific invention for achieving the above object is to provide a measuring means for performing a predetermined optical measurement on an eye to be inspected, an irradiation light source for irradiating the anterior segment of the eye to be inspected with light, An optometry apparatus comprising: a control unit that turns off the irradiation light source when performing a predetermined optical measurement.

The present invention relating to the above specified invention, an image pickup means for observing the anterior segment of the eye, a measurement means for performing a predetermined optical measurement on the eye to be examined, and a projection means for projecting an alignment mark on the image pickup means. An optometry apparatus, comprising: a control unit that turns off the light source of the projection unit during the predetermined optical measurement.

[0007]

In the optometry apparatus having the above-mentioned structure, the illumination light source which is not required at the time of measurement is turned off to facilitate the processing in the measuring means.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail based on the illustrated embodiments. FIG. 1 is an optical configuration diagram. In front of the eye E to be inspected, the objective lens 1 is sequentially arranged along the optical axis O1 from the eye E side to be inspected.
The light splitting member 2, the diaphragm 3, and the two-dimensional photosensor 4 are arranged,
A ring-shaped light source 5 is arranged around the objective lens 1. Furthermore, an optical axis that is orthogonal to the optical axis O1 and passes through the light splitting member 2.
A light source 6, an alignment target 7, a lens 8, a light splitting member 2, a lens 9, and a television camera 10 are sequentially arranged on O2, and the output of the television camera 10 is connected to a television monitor 11.

A reflected image of the cornea Ec of the eye E to be examined of the ring-shaped light source 5 is formed on the two-dimensional optical sensor 4 through the objective lens 1, the light splitting member 2 and the diaphragm 3, and the size thereof will be described later. The radius of curvature of the cornea Ec can be obtained by measuring with a means. On the other hand, as shown in FIG. 2A, the anterior segment image of the subject's eye E is displayed on the television monitor 11 by the television camera 10, and the anterior segment is illuminated by an external eye illumination light source of visible light (not shown). ing. The alignment target 7 is the visible light source 6
Is illuminated by the television camera 1 through the lenses 8 and 9.
It is filmed at 0. An iris image Pi, an image Pr of the ring-shaped light source 5, an image Pa of the alignment target 7, a pupil image Pp, and an external eye illumination light source image Ps are displayed on the television monitor 11 in FIG. 2 (a).

When the video signal of the scanning line 1 is shown in FIG. 2 (b), the sclera Es has strong reflection and the iris Ei is dark and has a low level. The signal can be binarized by setting the level L in the middle, and the size of the iris image Pi can be found by finding the distance between the intersections a and b by means described later. The scanning line 1 is off the center of the eye E to avoid the light source image Ps, and can be converted into the diameter of the iris image Pi if the amount of deviation is determined in advance.

FIG. 3 shows an electrical block circuit configuration diagram.
First, the measurement unit of the radius of curvature of the cornea will be described. The analog signal read from the two-dimensional optical sensor 4 is amplified by the amplifier 20 and the signal level is temporarily held by the sample value hold circuit 21. The digital signal is converted by the A / D converter 22. The optical sensor 4 is controlled by the clock signal of the driver 23. A
The digital signal output from the / D converter 22 is passed through the interface 24 and RAM (Random Access Memory).
25. Reference numeral 26 is a ROM (Read Only Memory) in which a control program for operating the microprocessor 27 is written. The ring image position formed on the two-dimensional optical sensor 4 is obtained from the data in the RAM 25,
The radius of curvature of the cornea is obtained by fitting it to a general formula such as an ellipse, displayed on the result display 28, and output to the printer 29 as necessary.

Next, the corneal diameter measuring unit will be described. The video signal of the anterior ocular segment image of the subject's eye E captured by the television camera 10 is supplied to the television monitor 11 and the amplifier 30,
It is input to the cycle separation circuit 31, and the scanning line counter 32 is operated. The output c from the scanning line counter 32 is connected to the interface 24. The video signal amplified by the amplifier 30 is input to the comparators 34 and 35 and the sample value hold circuit 36, and the comparator 35
Is output to the sample value hold circuit 36 via the monostable multivibrator 37. Comparator 3
The other input of 5 is connected to the pupil level setting signal d, its output e drives the monostable multivibrator 37, and its output f is its sample value hold circuit 3
Then, the output voltage h is added to the predetermined voltage signal g via the adder 38 and the output signal h is connected to the input terminal of the comparator 34. The output i of the comparator 34 is connected to the gate input of the counter 39, and count control is performed by the clock output j of the oscillator 40. The count output k of the counter 39 is input to the interface 24, and the control signal m of the counter 39 is sent from the interface 24 to the counter 39. Further, the ring-shaped light source 5 and the light source 6 are connected to the interface 24, and the turning on / off control is performed, and the ring light source 5 and the light source 6 are turned off when measuring the corneal diameter.

The operation of the measuring unit of the keratometer will be described with reference to FIG. 4. Since the pupil image Pp is close to the black level and there is no individual difference, the pupil level setting signal d may be constant. If the monostable multivibrator 37 is driven by the fall of the output signal e from the comparator 35 and the video signal at the time of the fall of the signal e is held as a sample value, the level Li of the iris image Pi is determined and the individual difference Can be suppressed. A predetermined level g is added to this level Li, and the level h and the output signal of the TV camera 10 are compared by the comparator 34.
The iris signal i can be extracted by comparing with. The signal h from the adder 38 is output for each scanning line while the pupil of the screen of the television monitor 11 is included. Based on the output c from the scanning line counter 32, when a predetermined scanning line is reached, a counter control signal m is output, the width of the iris signal i is counted by the clock output j, and the output k is read to determine the scanning line. The corneal diameter can be obtained by converting the diameter of the iris image Pi on l.

The measurement operation procedure is as follows:
First, while aligning the ring image Pr with the target image Pa with good focus while pressing the measurement button (not shown), the light sources 5 and 6 are turned off and the iris diameter, that is, the cornea diameter is measured. The light is turned on to measure the radius of curvature of the cornea, but the measurement procedure may be reversed. Further, since the iris has a high reflectance with respect to infrared light, it is desirable to use visible light for external eye illumination. Furthermore, if the observation optical system of the television camera 10 is a telecentric system, it is preferable because even if the image is blurred, the accuracy is not affected.

As another measuring means, a television monitor 1
A ring-shaped corneal reflection image Pr by the light source 5 is projected on the surface 1, and this image Pr is generally represented by an ellipse. This ellipse can be calculated by calculating the intersection of the rings by using at least three scanning lines of the ring-shaped image Pr.
Thereby, the radius of curvature of the cornea in each radial direction can be calculated.

Further, the microprocessor 27 may calculate the base curve of the contact lens based on the measurement results of the radius of curvature of the cornea and the diameter of the cornea, and output the result to the result display 28 and the printer 29.

[0017]

As described above, according to the eye examination apparatus of the present invention, in the optical measurement of the eye to be inspected, the unnecessary illumination light source is turned off to prevent the disturbance from being mixed in and facilitate the processing.

[Brief description of drawings]

FIG. 1 is an optical configuration diagram of a first embodiment.

FIG. 2 is a front view of a television monitor and a waveform diagram of a video signal of a specific scan line.

FIG. 3 is a block circuit configuration diagram.

FIG. 4 is a signal waveform diagram of a block circuit configuration diagram.

[Explanation of symbols]

 1 Objective Lens 2 Light Splitting Member 3 Aperture 4 Optical Sensor 5 Ring Light Source 6 Light Source 7 Alignment Target 11 TV Monitor 21, 36 Sample Value Hold Circuit 22 A / D Converter 25 RAM 26 ROM 27 Microprocessor 34, 35 Comparator 37 Single Stable multivibrator 38 Adder 39 Counter

Claims (2)

[Claims] 1. A measuring unit for performing a predetermined optical measurement on an eye to be inspected, and an irradiation light source for irradiating an anterior segment of the eye to be inspected with light.
An optometry apparatus comprising: a control unit that turns off the irradiation light source during the predetermined optical measurement. 2. An image pickup means for observing an anterior segment of the eye, a measurement means for performing a predetermined optical measurement on an eye to be examined, a projection means for projecting an alignment mark on the image pickup means, and a predetermined optical measurement. An optometry apparatus, further comprising: a control unit that turns off the light source of the projection unit.