JPH03188826A - Measuring device for adjusting power of eye - Google Patents

Abstract

PURPOSE:To accurately and promptly measure changes in the refractive power of an eye by using as a target for inducing adjustment a pattern having plural rectilinear components extending in the same direction. CONSTITUTION:Movement of a target 19 as stimulus for adjustment is added by a microcomputer circuit 121 to a microcomputer circuit 111 as a signal 1 following preset conditions of the amount, the starting point and the speed of movement of the target toward and away from an eye and the number of times that this movement is repeated. A driver 212 and a motor 213 then drive a third relay lens 17. A potentiometer 215 directly connected to the third relay lens 17 and a buffer amplifier 214 are provided and the signal is returned as a position signal of actual movement to the microcomputer circuit 121 through an A/D converter 105 by analog output (2) indicating the position of the target 19. The eye 6 to be tested is fixed on movement of the target 19 toward and away from it whereby changes in the refractive power of the eye can be measured succesively as movement of a spot diaphragm 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an accommodative power measuring device having an optotype suitable for measuring accommodative power.

[Prior art] In recent years, word processors, computers, etc.
Although DT work is on the rise, it is possible to quantitatively understand eye strain and physical fatigue by measuring fluctuations in the eye accommodation power of workers before and after work.

To measure eye accommodation, the position of a visible visual target is controlled to move from far to near and from near to far using an external signal, and the change in eye refractive power induced by this fixation target is measured. There are known devices that continuously measure over time.

By the way, in conventional eye accommodation measuring devices, when measuring eye refractive power, the subject is made to gaze at the center, and an index using a radial pattern such as a starburst that fixes the eye to be examined is also used for measuring eye accommodation. I am using it.

[Problems to be Solved by the Invention] However, when an optotype having such a radial shape is moved from the far point direction to the near point direction or in the opposite direction, the following problems occur.

Figure 5 shows constant refractive power change rate (unit: drop%c)
Locus a when the visual target is moved from the far point direction to the periapsis direction
and its opposite trajectory, and the change in eye refractive power induced by that stimulus is shown as ASB. Here, shifts c and d in A and B occur because the subject changes the direction in which he or she fixates the radial visual target.

This is because if the eye to be examined has astigmatism, there are two focal points, so there are two positions in each direction of the radiation where the lines appear darker, and the examinee unconsciously fixates the eye. It changes the direction of vision. Generally, these two directions are 9
It is a direction that forms an angle of 0 degrees, and is the direction of the puncture meridian and strong principal meridian.

The present invention was devised in view of the above-mentioned drawbacks, and an object of the present invention is to provide an accommodative power measuring device that can accurately and quickly measure changes in eye refractive power.

[Means for Solving the Problems] The ocular accommodation power measurement device of the present invention measures the ocular accommodation power of the eye to be examined by having the test subject fixate on a first visual target that moves in the optical axis direction. In the measuring device, the first optotype that induces accommodation is a pattern having a plurality of linear components extending in the same direction, and the direction of the straight line is determined by the astigmatism axis measured in advance using an input measurement means having a second optotype. The present invention is characterized by comprising an optotype presenting means that rotates so as to have a constant positional relationship with the target.

The input measuring means may be a known automatic eye refractometer built into the apparatus or attached externally, or may be other means for measuring the astigmatic axis.

[Operation: As in the above configuration, by making the optotype that induces accommodation into a pattern with multiple linear components extending in the same direction, the optotype is rotated to extract only the change in eye refractive power in a certain meridian direction. be able to.

Here, the specific meridian is either the puncturing meridian or the strong principal meridian of the eye to be examined, and the direction of the optotype can be rotated in these directions. Note that FIG. 4-1 is a graph showing changes in eye accommodation, and shows the case where the astigmatism axis is 30 degrees. In this case, when the visual target is near the far point, when viewed from the subject, a line in the 60 degree direction is clearly visible as shown in Figure 4-2. Subsequently, when the optotype is moved from far to near as shown in a of FIG. 5, the eye refractive power changes from el to e2. It can be said that the larger the distance between these 8102, the better the eye accommodation ability.

[Example] Hereinafter, the invention will be explained in detail with reference to the drawings.

FIG. 1 shows an example of the arrangement of the measurement optical system of the ocular accommodation measuring device according to the present invention, in which 1 is a measurement light source having a wavelength in the infrared region, which is placed approximately at the focal point of the condenser lens 2. has been done. 3 is a movable spot aperture so as to be placed at a position conjugate with the fundus of the eye 6 to be examined; 4 is an objective lens; and 5 is a beam splitter. 7 is an objective lens, 8 is a beam splitter, 19 is a first relay lens, and 10 is a corneal reflection removal mask disposed at a position conjugate with the cornea of the eye 6 to be examined. 12 is a second relay lens, 13 is a moving lens that moves together with the spot diaphragm 3, and 14 is an imaging lens. Reference numeral 15 denotes a measurement light receiving element, which rotates around the optical axis in synchronization with the measurement light source 1 and the corneal reflection removal mask 10. 16 is a reflecting mirror. A third relay lens 17 is movable in the axial direction. 18
is the fourth relay lens. 19 is a fixation target projected onto the fundus of the eye 6 to be examined. This optotype 19 is No. 4-2
As shown in the figure, the pattern includes a linear component extending in one direction, and can be rotated by a drive unit, which will be described later. 21
is a condensing lens, and 22 is a visible light source.

FIG. 2 shows the overall system components for eye accommodation measurement.

Reference numeral 101 denotes an optotype presentation unit that includes an optotype 19 that rotates around the optical axis and moves in the far/near direction on the optical axis; I10 circuit 104;
It is controlled by the microcomputer circuit 121- via the microcomputer circuit 121-. 102 is a part of an optometer that detects the eye refractive power, and the eye refractive power change signal obtained as an analog voltage is connected to the microcomputer circuit 121 via the A/D circuit 105. Reference numeral 103 is an observation system for aiming between the eye to be examined and the apparatus. 111 is a microcomputer circuit, which includes an optometrist part 101 and an optometa part 10.
2 to satisfy the eye refractometer function and the eye refractometer function. The microcomputer circuit 121 has a built-in program that simultaneously displays the movement change (stimulus) of the optotype 19 and the eye refractive power change (reaction) on the display 122, and stores it in the external storage device 123 as a time-varying waveform. 124 is a printer.

FIG. 3 is a block diagram showing the signal processing system of the automatic eye refractometer section of this apparatus.

The function as an automatic eye refractometer will be omitted, and the measurement of eye accommodation power will be explained below according to the procedure.

Obtain the values of spherical surface, cylindrical refractive power, and astigmatic axis by measuring with an eye refractometer. Next, the device is switched to a measurement mode selector switch (not shown) or a signal (1) from the microcomputer circuit 121.
Switch to accommodative power measurement mode. The microcomputer circuit 111 connects the motor 2 via the driver 208.
09, measurement light source 1, corneal reflection removal mask 10
Then, the light receiving element 15 is rotated in alignment with the astigmatic axis. Also, based on the angle of the astigmatic axis, the microcomputer circuit 111
drives the motor 211 via the driver 210 to rotate the optotype 19 in the principal meridian direction perpendicular to the astigmatism axis when expressing astigmatism in a negative form.

Next, the signal from the microcomputer circuit 121 (
1) The measurement start signal is sent to the microcomputer circuit 11.
1, the driver 201 outputs the measurement light source 1.
is caused to emit light at a predetermined pulse cycle, and the image of the spot aperture 3 is projected into the eye and onto the fundus. The reflected light is detected by the light receiving element 15. Then, the phase detection circuit 202 converts it into a DC voltage proportional to the focus quality of the image projected on the fundus, and the voltage is passed through the A/D converter 203 to the microcomputer circuit 1.
Added to 11. The microcomputer circuit 111 moves the position of the spot diaphragm 3 by driving a motor 205 via a driver 204 until the best focus is achieved. The position of the spot diaphragm 3 corresponds to the eye refractive power value, and a potentiometer 20 connected to the spot diaphragm 3 corresponds to the eye refractive power value.
The eye refractive power value is obtained as the voltage output (3) of 7. Then, until the measurement stop signal (1) is received from the microcomputer circuit 121, the change in the eye refractive power of the eye 6 to be examined is always output as an analog signal to the microcomputer circuit 121.
Output to. Note that 206 is a buffer amplifier.

Movement of the optotype 19 as an accommodation stimulus (in this embodiment, an optical system is used in which an equivalent effect can be obtained by moving the third relay lens 17. There are two methods: one is to gradually move the point further to the minus side, and the other is to instantly move the point between the far point and the near point in a stepwise manner at regular intervals. , the microcomputer circuit 111 as a signal (1) according to setting conditions such as the start position of movement, speed of movement, and number of repetitions.
It is done by being added to.

Here, the driver 212 and motor 213 drive the third relay lens 17. Further, 215 is a potentiometer directly connected to the third relay lens 17, 214 is a buffer amplifier, and (2) is an analog output indicating the position of the visual target 19, which is sent as an actual position signal through the A/D circuit 105. It is returned to the microcomputer circuit 121.

As a result of the subject's eye 6 fixating on the movement of the optotype 19 from far to near, it is possible to continuously perceive the change in the eye's refractive power as the movement of the spot diaphragm 3.

Here, the optotype 19 is made circular so that it can be rotated, and the group of straight lines has an appropriate area so that its presence can be recognized even when it is moved to a distance and becomes blurred. Specifically, the width of the lines and the spacing between the lines are, for example, 1:1, and the visual acuity is equivalent to 0.7.

The area should be large enough to limit the fixation position and should be as required by the eye refractometer. In this embodiment, it is from 1 degree to 2 degrees.

Although this embodiment has been explained using optotypes 0 to 19 built into an automatic eye refractometer, it is also possible to similarly provide a function as an input measurement means to an optotype manufactured to be installed externally. . On the other hand, a plurality of optotypes may be arranged on the disk by separately providing optotypes for canceling accommodation used in the automatic eye refractometer function.

All you have to do is rotate and switch between each measurement.

Furthermore, although the microcomputer circuit is divided into 111 and 121, they may be unified into one microcomputer circuit.

[Effects of the Invention] According to the accommodative power measurement device of the present invention, the accommodative power of a subject can be easily and quickly measured accurately without changing the direction in which the subject fixates the visual target. .

[Brief explanation of drawings]

FIG. 1 is an optical layout diagram showing the main optical system of the embodiment. FIG. 2 is a block diagram showing the system components of the eye accommodation measuring device. FIG. 3 is a block diagram of the signal processing system. FIG. 4-1 is a graph showing changes in the eye refractive power of the subject. Figure 4-2 1 is a diagram showing optotypes. FIG. 5 is a graph showing the constant refractive power change rate. 6...Eye to be examined 19...Optotype 101...Optotype presentation section 102...Optometer part 103...Observation system 111.121...Microcomputer circuit

Claims (4)

[Claims] (1) In an accommodative power measurement device that measures the accommodative power of the eye to be examined by having the subject fixate on a first optotype moving in the optical axis direction, the first optotype is arranged in a plurality of eyes extending in the same direction. a pattern having a straight line component, and includes a first optotype presenting means for rotating the direction of the straight line so as to have a constant positional relationship with an astigmatism axis measured in advance using an input measuring means having a second optotype. An accommodative power measuring device characterized by: (2) The accommodative power measuring device according to item 1, wherein the input measuring means is an automatic eye refractometer capable of measuring an astigmatic axis. (3) The eye accommodation power measuring device according to item 2, wherein the optical system of the first optotype is the same as the optical system of the second optotype. (4) The eye accommodation power measuring device according to item 3, wherein the first optotype shares the second optotype.