JPH0310726Y2 - - Google Patents

Description

[Detailed explanation of the idea]

Industrial Application Fields This invention presents optotypes corresponding to each level of visual ability to the left and right eyes of the subject's eye independently or to both eyes at the same time, and has the examinee respond with the visual recognition status of the optotypes. Regarding the visual acuity meter that tests the visual acuity of the subject based on its accuracy,
In particular, it relates to improvements in the optical system. Technical background In recent years, the above-mentioned visual acuity meters have been developed to facilitate the presentation operation by electrically selecting a predetermined one from among a plurality of optotypes and presenting the optotype. In order to make it easy to electrically input the visual recognition status of the target, electrically judge whether the answer is correct, and further statistically process the judgment results, the visual target is formed by an electro-optical display means. There is. However, there is a limit to the size of the transparent electrode that is essential for optotypes using electro-optic display means, and it is not possible to create small optotypes that correspond to high visual acuity, and the accompanying optical system is also small. Therefore, it has been impossible to make the visual acuity meter smaller and lighter. Therefore, the present inventor created a visual target for high visual acuity by photoetching that can form a precise pattern, and placed an electro-optic shutter element just before this to stop selective presentation and presentation of the visual target by the shutter action. It is proposed to form a small and lightweight visual acuity meter by controlling the visual acuity and forming an optotype for low visual acuity by electro-optical means. Note that in this type of visual acuity test, a monocular visual acuity test is performed with both eyes open.
For example, while presenting an optotype to the right eye for a right eye visual acuity test, it is not allowed to close the left eye optical path or leave the left eye optotype plate unilluminated. By the way, in certain designs of visual acuity meters that have an optotype presentation means created by photoetching the above-mentioned precise pattern, when the optotype is presented to one eye to be examined, the optotype is not displayed to the other eye. The electro-optic shutter element that should be prevented from being presented is visually recognized by the subject's eye, and the subject observes the above-mentioned photoetching target image and the electro-optical shutter element image overlappingly due to the fusion effect, resulting in an inappropriate image. Accurate visual acuity measurements may not be performed. Purpose of the invention The present invention provides an optical acuity meter with an illumination light flux that enters the eye to which the optotype light flux is not projected.
It is an object of the present invention to provide a visual acuity meter capable of accurately determining visual acuity with both eyes open. Structure of the device The structure of the device is characterized by two projection optical systems that project the light from the optotype plate independently into the right and left eyes of the subject, and a light source that projects the light from the background light source. Projects independently to the right and left eyes 2
When the two background optical systems and the projection optical system project a target light beam onto one eye, the projection optical system and the background optical system are arranged so that the background optical system projects the background light beam onto the other eye. A control system was installed to control the Effects of the Invention According to the present invention having the above-described configuration, when an optotype is presented to one eye to be examined in the visual acuity meter, background light is incident on the other eye, and the eyes are opened in a state where both eyes are open, resulting in natural vision. This has the advantage that the influence of mechanical myopia is reduced, fusion of the subject's eye is prevented, and a proper visual acuity test can be performed. Embodiment (1) External configuration FIG. 1 is an external perspective view showing an embodiment of an automatic visual acuity testing device (hereinafter simply referred to as a visual acuity meter) according to the present invention. On the operation panel 11 located in front of the pedestal 10 on the subject's side, there is a start switch 12 consisting of a push button switch for starting the measurement.
and an answer switch 13 for answering the cut direction of the Landolt optotype visually recognized by the subject. An apparatus housing 15 stands upright on the pedestal 10, and two windows 16 are provided on the front side of the housing 15 on the subject's side to allow the subject to look at the optotype with both eyes.
a, 16b, and a forehead rest member 17 are provided. Furthermore, a printer 19 is attached to the housing 15 to print out the test results. This printer has a calendar input device 19a for inputting the year, month, and day of the inspection date. The answer switch 13 has a pyramid-shaped central projection 20, as shown in FIGS. 2A and 2B.
, push button switches 21 to 24 are arranged front to back, left and right around this center, and each switch is used to indicate to the subject which cut direction of the Landolt optotype each of these push button switches corresponds to. It is composed of Landolt marks 21a to 24a displayed close to each other. Even if the examinee constantly looks into the windows 16a and 16b,
With this configuration, it is possible to know the overall arrangement of the answer switch 13 and the positions of the push button switches 21 to 24 based on the tactile sensation of the central protrusion 20. At the rear of the upper surface 18 of the housing 15, an operator operation panel 30 shown in FIG. 3 is disposed. This operation panel 30 includes a power switch 301 consisting of a toggle switch with a built-in pilot lamp, a measurement sequence setting knob 302, an optotype presentation time setting knob 303, and examination menu setting switches 304 to 310 consisting of push button switches. A switch 311 for turning on the astigmatism chart, an optical path selection switch 312 for selecting whether to put the astigmatism chart into the left eye optical path or the right eye optical path, and a push-button end switch provided to end the measurement. 313, pilot lamps 304a to 310a for displaying the ON-OFF status of each test menu setting switch, pilot lamps 315a and 315b for indicating which of the left eye or right eye is being measured, and a visual acuity of 0.7. Judgment lamps 316a and 316b for indicating the judgment result of the measurement using the optotype as "pass" or "fail", and a liquid crystal display panel 320 for indicating the optotype presented to the subject during the measurement as a visual acuity value. is installed.
Here, each of the above-mentioned pilot lamps 304a to 316b is composed of an LED. (2) Optical system Figure 4 shows the optical layout of this visual acuity meter. The right eye optical path OR and the left eye optical path OL have the same configuration. The light emitted from the optotype illumination light sources 40R, 40L is reflected by the concave mirrors 41R, 41L, and then the light emitted from the optotype illumination light source 40R, 40L is reflected by the optotype plate 42.
Illuminate R and 42L. The optotype plates 42R, 42L are arranged at the focal positions of the distance lenses 43R, 43L arranged in the windows 16a, 16b. The light from the optotype plates 42R and 42L is passed through a half mirror 44.
After being reflected by R, 44L, mirrors 45R, 45
Reflected by L, 46R, 46L and lens 43R, 4
The light is made into a parallel light beam by 3L and enters the eye E to be examined. Normally, when testing the visual acuity of one eye, a visual target is not presented to the other eye, but it is said that it is necessary to provide a bright field similar to that of the eye to be measured. Therefore, in this embodiment, the bright field light sources 47R, 47
L and diffusion plates 48R and 48L. For example, when testing the right eye, the optotype plate 42R is illuminated with the light source 40R, and the optotype is presented to the subject's right eye ER.
At this time, the light source 47L of the left eye optical path OL is also turned on, and the light diffused by the diffuser plate 48L is transmitted through the half mirror 44L and then reflected by the mirrors 45L and 46L, giving a bright field to the subject's left eye EL. The distance lenses 43R and 43L have auxiliary lens groups 49R and 49L. These auxiliary lens group 4
9R and 49L are, for example, lenses 491R and 491L for farsightedness examination having a refractive power of +0.5D, for example, +
Near vision inspection lens 492R with 3.0D refractive power,
492L and pinhole plates 493R and 493L each having a large number of pinholes. These auxiliary lens groups 49R, 49L are mounted on turret plates 495R, 495L, as shown in FIG.
and selectively inserted into their respective optical paths. Transparent apertures 494R and 494L are also formed in the turret plates 495R and 495L, and are placed in the respective optical paths during long-distance inspection. These turret plates 495R, 495L have gears 4 on their rotating shafts 497R, 497L, respectively.
It has 98R and 498L. These gears 49
8R, 498L has tension belt 499R,
499L is hung, and two belts 499
R and 499L are connected to a gear 496a attached to one end of the rotating shaft of the pulse motor 496. With this configuration, the rotation of the motor 496 rotates the turret plates 495R and 495L. On the other hand, a slit plate 500 having a slit 500a is provided at the other end of the rotating shaft 496a of the motor 496.
is installed. This slit 500a corresponds to apertures 494R and 497L,
When this slit 500a is rotated to the position of the photo interrupter 501 which is its detector, the apertures 494R and 494L are set in the respective optical paths.
It is configured to be located within OR and OL. The optotype plates 42R and 42L each include a diffuser plate 421, a liquid crystal plate 422, and a mask plate 423, as shown in FIG. The diffusion plate 421 functions to diffuse the light from the light source 40. As shown in FIG. 6, various patterns 401 to 409 are formed on the liquid crystal plate 422, which turn black when energized. Landolt optotype pattern 401
Among patterns 409 to 409, patterns 401 to 405 corresponding to visual acuity of 0.1 to 0.5 have circular arc portions 40 so that cuts in four directions can be selectively switched and displayed.
1a and each cut portion 401b are formed independently. Then, for example, the rightward Landolt optotype is obtained by energizing and blackening everything except the right cut portion 416b. On the other hand, patterns 406 to 409 corresponding to a visual acuity of 0.6 to 0.9 are configured as a group of four Landolt optotypes whose cut directions are vertical, horizontal, and vertical. Further, a sunburst type astigmatism table pattern 410 is formed on the liquid crystal panel 422, and a clock time display pattern 411 is formed on each meridian so that the direction thereof can be easily determined. Below the astigmatism table pattern 410 are 16 rectangular patterns 412a.
Shutter row pattern 41 formed by arranging in a row
2 is formed. Shutter row pattern 41
Further below 2, a shutter group 413 for stereoscopic viewing charts is formed to control the presentation of stereoscopic viewing charts, which will be described later. The mask plate 423, as shown in FIG.
Visual acuity 1.0, 1.2, 1.5 and
A total of 16 Landolt optotypes 415 in four directions (up, down, left, and right) corresponding to 2.0 are arranged in groups of four. In this example, from the right side of the figure, 1.0, 1.2,
Visual targets corresponding to visual acuity of 1.5 and 2.0 are arranged. Below the Landolt optotype column 416, there is a diamond-shaped 5
Openings 416a, 416b, 416c, 41
A mask portion 417 is formed in which 6d and 416e are formed to correspond to the above-described shutter group 413 for stereoscopic viewing charts. Four small diamond shapes 418 are formed in each of the openings, one of which is shifted in position from the other small diamond shapes in the horizontal direction. For example, the small diamond shape 419a within the opening 416a has a center-to-center distance of D ₁ (D ₁ >S) with respect to the reference center-to-center distance S of other small diamond shapes.
One of the diamond shapes 419b to 419e in the other openings 416b to 416e also has a center-to-center distance of D ₂ to D ₅ , respectively. Here D ₁ > D ₂ >
There is a relationship of D ₃ >D ₄ >s>D ₅ , and the deflection directions in this embodiment are all in the right horizontal direction. In this embodiment, the stereoscopic chart 416a represents a parallax of 4', and the chart 416b represents a parallax of 1'.
16c has a parallax of 3', and chart 416d has a parallax of 3.
0'', and the chart 416e is configured to give a parallax of 2'. The embodiment shown in FIG. 7 is a mask plate for the right eye, and the mask plate for the left eye is the same as the mask plate shown in FIG. The patterns 415 and 415 described above are formed mirror-symmetrically.
417 is formed by depositing chromium on a glass substrate. (3) Electrical system Figure 8 is a block diagram showing the electrical system of this vision meter. The electrical system is a ROM (read-only) that stores the inspection sequence program described later.
memory) 606 and RAM (random access
to control the entire electrical system according to the sequence stored in memory) 608 and ROM 606.
CPU (Central Processing Unit)
607 and a drive system 60 for each of the aforementioned components.
0 and an interface 605 that communicates between the drive system 600 and the CPU 607. The CPU607 has a CTC (counter timer)
circuit) 609 is connected. CTC6
09 is a pulse for controlling the rotation of the pulse motor 496 and a liquid crystal plate 4 of the optotype plates 42R and 42L.
The CPU sends pulses to select the cut direction of the Landolt optotype presented by 22R and 422L.
607. That is, the CTC 609 is configured as a down counter whose lower four digits decrease sequentially from "1111" to "0000" as shown in Table 1. This down counter starts at the same time as the power is turned on and is constantly executed.

[Table] The CPU 607 uses CTC 6 immediately before the visual target presentation step.
Read the count of 09, and if the last two digits of the count value are "11", the break of the Landolt optotype is on the "top", and if it is "10", it is on the "bottom", so it is "01". If "right" is "00"
In this case, select each Landolt optotype as shown on the "left". With this configuration, the direction of the break in the Landolt optotype is randomly presented due to the randomness of both the time from power-on until the test subject turns on the start switch 12 and the time from power-on to the response time from the answer switch 13. The drive system 600 includes the operation panel 30, a driver circuit 601 for driving the liquid crystal panel 320,
Driver circuit 602 for lighting the light sources 40R, 40L, 47L, 47R, optotype plates 42R, 42
It is roughly composed of driver circuits 603 and 604 for driving the liquid crystal panels 422R and 422L, respectively, and a speaker 610 and its driver circuit 611 for producing sound when an answer is input by the answer switch. Measuring Method and Operation of the Apparatus (1) Overall Measurement Flow FIG. 9 shows a flowchart showing the entire measurement procedure by this visual acuity meter, which will be explained in detail below. Step 1-1: Switch the power switch 301 on the operation panel 30 to "on" to turn on the power. Step 1-2: The CPU 607 communicates with the photo interrupter 5 via the interface 605.
01 detects the slit 500a, that is, whether the transparent aperture 494
It is determined whether R, 494L is located within the optical path. Photo interrupter 50
1 does not detect the slit 500a, the pulse motor 496 is
The apertures 494R and 494L are positioned within the optical path by rotating with the pulse output from the aperture 494R and 494L. Also, CPU607 is RAM60
Delete the previous data saved in 8. Step 1-3: The examiner uses the operation panel 30 to select and set the measurement sequence, examination menu, and optotype presentation time. In other words, the measurement sequence is set using the setting knob 30.
2, and in the case of a naked eye or correction test, the knob 302 is set to the "naked eye" or "correction" position. If it is desired to automatically perform the correction examination after the naked eye examination, the knob 302 is set to the "naked eye+correction" position. Next, the optotype presentation time is determined by the knob 303 in consideration of the subject's age, test experience, familiarity, etc. In this example,
When set to "1", a visual target presentation time of 3 seconds, when set to "2", 5 seconds, and when set to "3", 7 seconds is obtained. Timing is performed by the CTC 609, and when a desired time has arrived, the CPU 607 controls the driver circuit 603 to erase the visual target. The inspection menu is a push button switch 30.
Set by pressing 4 through 310. The "binocular" menu (switch 310) automatically shifts to binocular testing after the right eye test and left eye test. If this "binocular" menu is not selected, a monocular examination will be performed for each of the left and right eyes. Step 1-4: The CPU 607 executes the measurement sequence, inspection menu, and
The optotype presentation time is read, and then the light source 40R of the right eye optical path and the light source 47b of the left eye optical path are turned on to complete measurement preparation. Step 1-5: The CPU 607 determines whether or not the start switch 12 has been turned on by the subject. If it has been turned on, the process proceeds to the next step 1-6. If it remains OFF, return to the previous step 1-3 so that you can respond to changes in the measurement sequence or inspection menu. Step 1-6: A measurement processing subroutine to be described later is executed based on the setting measurement sequence, setting inspection menu, etc. read in step 1-4. Step 1-7: The CPU 607 counts the number of times the set inspection menu is passed, that is, the number of times it is executed. Step 1-8: The CPU 607 determines whether or not it is necessary to proceed to step 1-9, which determines the number of passes in the previous step 1-7, according to the set measurement sequence. Measurement sequence is "naked eye + correction"
If it is set to , proceed to the next step 1.
Proceed to -9. If it is set to "Naked eye" or "Correction", proceed to the next step 1-9.
Skip over this and move on to step 1-10. Step 1-9: Check whether the number of passes counted in Step 1-7 is 2 or more. That is, two tests are performed: an inspection of the all-settings test menu with the naked eye, and an test of the all-settings test menu in the correction state. Determine whether or not it has been executed. If two tests have been performed, the process moves to the next step 1-10. If it is less than twice, the process moves to step 1-11, where the subject is made to wear glasses or contact lenses and prepare for a vision test in a corrected state. After completing the preparations, the subject turns on the start switch 12 again (step 1-1).
2) Perform steps 1-6 and subsequent steps again to test the effectiveness of the correction state. Step 1-10: Number of passes N in steps 1-9
If it is determined that ≧2, the measurement result, that is, the subject's visual acuity is printed out using the printer 19. In addition to visual acuity values for the left and right eyes, the printout also includes binocular visual acuity, 0.7 precision test pass/fail judgment results, stereoscopic vision ability results, etc. depending on the setting test menu. The examination date set by the calendar input device 19a is also printed. When the printout is completed, the apparatus returns to step 1-2 and enters the initial state for the next patient. (2) Measurement processing subroutine FIG. 10 is a subroutine flowchart showing steps 1-6 of the above-mentioned measurement processing in more detail. Based on the inspection menu read in step 1-4, the CPU 607 determines whether or not to execute the measurement processing steps (steps 2-1 to 2-6), and if the determination result is "YES", each test ( Step 2-7 or Step 2
-12) is executed. The subroutines of each test will be explained below. Note that when the hyperopia check test (step 2-9) or pinhole check test (step 2-10) is selected alone,
The CPU607 first performs a distance visual acuity test (Step 2).
-7), each test step is executed, and the test results of the two are compared. (3) Screening test Figure 11 shows a flowchart of the screening test. This screening test includes the distance visual acuity test (step 2-7), the near visual acuity test (step 2-8), and the hyperopia check test (step 2-7) of the measurement processing subroutine described above.
9) and pinhole check test (Step 2)
-10) are commonly performed for testing the left eye, right eye, and both eyes. However, lenses 492R and 492L are used during the near vision test, while lenses 491R and 491L are used during the far vision check test.
However, the difference is that pinhole plates 493R and 493L are each inserted into the optical path during the pinhole check test. Insertion of these lenses is
CPU607 has ROM60 in advance corresponding to each lens.
The motor 496 is rotated by matching the number of pulses stored in the CTC 609 with the number of pulses input from the CTC 609. The operation of each step will be explained below using a distance visual acuity test as an example. Step 3-1: The CPU 607 first uses the pilot lamp 304 to indicate to the examiner that the distance visual acuity test will be performed from the subject's right eye.
Turn on a and 315b. Next CPU60
7 clears the previous data stored in the failure number storage area of the RAM 608.
Reset to . Step 3-2: The CPU 607 controls the visual acuity of the liquid crystal panel 422R via the driver circuit 603.
Among the Landolt optotypes 407 of 0.7, a Landolt optotype in either the left, right, upper or lower cut direction is presented based on the combination of the last two digits of the count value of the CTC 609 at that time, and the response switch 13 receives an answer from the test subject. wait. When switch 13 is pressed, speaker 61
1 says "Pitsu" and confirms the switch response. At the same time, the visual acuity value of 0.7 of the presented optotype is digitally displayed on the liquid crystal panel 320. Here, each Landolt optotype is displayed within a predetermined time period, for example, 0.5 at the initial stage of presentation.
The optotype is blinked for a few seconds to make it easier for the subject to visually recognize the presentation position. This is CTC6
In this embodiment, the counter from 09 is read by the CPU 607, the CTC 609 counts every 0.1 msec, and when the last digit of the count value is "1", the LCD screen 42
The driver circuit 6 is configured by the CPU 607 to drive 2R to present the visual target, and to stop driving and not present the visual target when the last digit is "0".
This is achieved by controlling 03. If the answer from the subject matches the cut direction of the presented Landolt optotype, the CPU 607 causes the process to proceed to step 3-4. If the answers do not match or there is no answer within the visual target presentation time, proceed to step 3-
Move to 3. When the answers do not match, the speaker 611 utters "Peets" to warn the subject. Step 3-3 and Step 3-11: CPU6
07 is CTC60 at the start of execution of this step
The cutting direction of the Landolt optotype is determined from the last two digits of the count value of 9, and the driver circuit 603 is controlled to present the Landolt optotype 401 with visual acuity of 0.1. FIG. 12 shows an example of the presentation. At the same time, the display on the liquid crystal board 320 is changed to 0.1. The CPU 607 determines whether or not there is an answer from the subject within the presentation time and whether the response matches the cut direction of the presented Landolt optotype. If "YES", the process moves to step 3-4, and if there is a mismatch or If no answer is given, proceed to step 3-11, and the test subject's visual acuity is 0.1.
The following information is stored in the RAM 608, and the process proceeds to the next step 3-12. Step 3-4: The optotype presented last time (if the previous step was Step 3-2, the optotype with visual acuity of 0.7,
If the previous step is step 3-3, visual acuity
(0.1 visual target), that is, a visual target one step higher in visual acuity (0.8 visual target if the previous step is step 3-2, 0.2 visual target if the previous step is step 3-3) )
have them present. At this time, the cut direction of the Landolt optotype presented is the same as that at that time.
It is determined from the last two digits of the count value of CTC 609. FIG. 12B shows an example of presentation of a Landolt target of 0.6. LCD board 3
20 displays 0.8 or 0.2. Step 3-5: Determine whether or not the subject answers the direction of the cut in the Landolt optotype via the answer switch 13 within the optotype presentation time, and whether the answer matches the cut in the Landolt optotype that was presented. The CPU 607 determines whether or not it was. If the determination is ``YES'', the process moves to step 3-6, and if the determination is ``NO'', the process moves to step 3-7. Step 3-6 and Step 3-8: Step 3
It is determined whether the Landolt optotype presented in step -4 is the minimum optotype, that is, the Landolt optotype with a visual acuity of 2.0. If "YES", the process moves to step 3-8, and the RAM 608 records the visual acuity of the subject's eye as 2.00. This is stored and the process proceeds to the next step 3-12. If the determination is "NO", the process returns to step 3-4 and a Landolt optotype that is one step smaller than the previously presented optotype is presented. FIG. 12C is an example of presentation of the Landolt optotype for a visual acuity of 1.5. 1.0,
For the optotypes 1.2, 1.5, and 2.0, not the Landolt optotype itself but the corresponding Landolt optotype on the mask plate 423 can be observed by erasing the rectangular pattern 412a of the shutter row pattern. Step 3-7: Since the determination of “NO” was made in the previous step 3-5, the CPU 607
608, 1 is stored in the failure number storage area. If the number of failures N is already stored in the failure memory area, 1 is added to it. Step 3-9 and Step 3-10: Number of failures N
If it is ``YES'', proceed to step 3-10, and use the visual acuity value of the presented optotype immediately before the presented optotype for which the number of failures was 2 as the visual acuity of the eye to be examined. The data is stored in the RAM 308, and the process proceeds to the next step 3-12. If the judgment is “NO”, step 3
Returning to -4, a visual target one step smaller than the currently presented visual target is presented. Step 3-12: Execute the next inspection program. For example, if the main screening is the right eye test of the distance visual acuity test (step 2-7), the next test program will be the left eye test, turning on the light sources 40L, 47R and the pilot lamp 315a, and proceeding to step 3-7 described above. Execute steps 1 to 3-12. If the main screening is a left eye test and the binocular mode (switch 310) is selected, the next test will be a binocular test using light sources 40R, 40.
L, pilot lamp 315a, 315b
Turn on the light and follow steps 3-1 to 3-
11. If the binocular examination is the main screening test, the next step will be step 2-2. In the distance visual acuity test, near visual acuity test, hyperopia check test, and pinhole check test described above, if an astigmatism check is necessary, press the astigmatism chart light switch 31 on the operation panel 30.
1 and the optical path selection switch 312, the astigmatism chart can be presented to the subject at any time (even during the measurement). FIG. 12D is an example of presenting an astigmatism table. The subject is asked to judge whether each meridian of the presented astigmatism chart can be seen with uniform shading. If there is a difference in shading depending on the direction of the meridian, have the students verbally answer in which direction the meridian appears darker using the ``time'' written on the meridian. This invention has the advantage that the astigmatism test is not incorporated into the measurement routine and can be inserted at any time during the measurement, allowing the tester to perform the test whenever they suspect astigmatism. be. Furthermore, if the test subject's answer, which is the basis for the judgment in step 3-2 above, is based on estimation rather than visual recognition, even if it is determined to be a correct answer, in the flow of Figure 11, it is less than 0.7. should not be recognized as true vision. As a countermeasure for this, the first
It is recommended to add step 3-2b, which is indicated by a broken line in Figure 1. In step 3-2b, as shown in Fig. 13, if the answer is ``YES'' in step 3-2, the visual acuity is the same as the previous time until the number of correct answers Y becomes Y=2.
Present the Landolt optotype, which is 0.7 but whose cut direction is different from the previous optotype, and have the child answer again. The purpose of using an optotype with a cut in a direction different from the previous one is to make it easier to detect the effects of astigmatism. In addition, the number of correct answers Y is
When =2, proceed to the next step. If it is desired to add a measurement exclusion step due to coincidence, the step 3-2b-1 described above can be added after step 3-6. In addition, there are lenses 491R and 49 for farsightedness inspection in the optical path.
If the far vision check test performed by inserting the 1L or the pinhole check test performed by inserting the pinhole plates 493R and 493L into the optical path is selected, the results of the distance vision test stored in the RAM 608 and Each test result
The CPU 607 compares the visual acuity values, and if the visual acuity value improves, the printer 19 prints out, for example, "Shiriyoku Koujiyou". (3) 0.7 precision test This 0.7 precision test is used to test visual acuity for the issuance of a driver's license, and uses 0.3 optotypes and 0.7 optotypes as shown in Figure 14. That is, in the 0.7 precision test, first, in step 4-1, 0.3 optotypes are displayed for the right eye in four directions, and it is determined whether or not the correct answer has been given in three or more directions. Step 4-
If a correct answer is given in 3 or more directions in step 1, the process advances to step 4-2. In step 4-2, 0.3 optotypes for the left eye are displayed in four directions, and it is determined whether or not a correct answer has been given in three or more directions. Step 4-
If a correct answer is given in 3 or more directions in step 2, the process advances to step 4-3. In step 4-3, 0.7 optotypes are displayed for both eyes in 4 directions, and 3
It is determined whether a correct answer has been given regarding the direction or more. If the correct answer is given in three or more directions in step 4-3, the process proceeds to step 4-4, where it is determined that the 0.7 precision test has passed, and the pass judgment lamp 31
6a, and step 4-1, 4-2,
If no correct answer is given in any of the three directions in step 4-3, the process proceeds to step 4-5, where it is determined that the 0.7 precision test has failed, and the failure determination lamp 316b is turned on. Each step 4- of the flowchart in Figure 14
The flow common to 1, 4-2 and 4-3 is the 15th flow.
As shown in the figure, it consists of the following steps. Step 5-1: Reset the number of failures N in the failure number storage area in the RAM 608 to 0. At the same time, the number of correct answers Y in the correct answer number storage area in the RAM 608 is also reset to zero. Since the measurement starts from the right eye (step 4-1), the light sources 40R and 47L are turned on.
Further, the CPU 607 confirms that the transparent apertures 494R and 494L are located in the optical path based on the ON signal from the photo interrupter 501. Step 5-2: The CPU 607 determines the cut direction of the Landolt optotype from the last two digits of the count value from the CTC 609 at the time of transition to this step, and sets visual acuity 0.3 in the cut direction (visual acuity 0.7 in step 4-3). ) is presented as the Landolt optotype 403 (407). 0.3 or 0.7 is displayed on the liquid crystal board 320. RAM the cut direction of this presented Landolt optotype.
608. Step 5-3: Check whether the subject answered within the visual target presentation time or whether the answer was correct.
The CPU 607 makes a determination. Judgment is "YES"
If , go to step 5-4, the judgment is "NO"
In each case, the process moves to step 5-5. Step 5-4: Add 1 to the number of correct answers Y in the correct answer number storage area of the RAM 608 and store it again. Step 5-5: Add 1 to the failure number N in the failure number storage area of the RAM 608 and store it again. Step 5-6: CPU 60 determines whether Y+N=4 or not.
7 is judged. That is, it is determined whether the Landolt optotype of 0.3 (or the optotype of 0.7 in the case of step 4-3) has been presented to the subject for all four types of breaks. If the number of presentations Y+N is determined to be Y+N<4, proceed to step 5-7.
If it is determined that this is the case, the process moves to step 5-8. Step 5-7: A Landolt optotype having a cut direction other than the Landolt optotype stored in the RAM 608, that is, a cut direction that has not been presented yet, is presented. Then, the process returns to step 5-3 again. Step 5-8: Determine whether the number of correct answers Y is Y≧3. When Y≧3, it is judged as a failure and the process proceeds to step 5-10, and immediately proceeds to step 4-1.
5, and the judgment lamp 316b is turned on. If the number of correct answers Y is Y≧3, the process moves to step 4-2 and steps 5-1 to 5-8 are executed again for the left eye. if,
If the actual step is step 4-3, that is, a test step for a 0.7 optotype in binocular vision, the process moves to step 4-4 based on the determination at step 5-9, and the determination lamp 316a is turned on. (4) Stereoscopic vision test The stereoscopic vision test 2-12 consists of the following steps, as shown in FIG. Step 6-1: The CPU 607 controls the driver circuit 602 to turn on the light sources 40R and 40L and turn off the light sources 47R and 47L.
Next, by controlling the driver circuits 603 and 604 to open the shutter 413 at a position corresponding to the stereoscopic chart 416a of the parallax 4' of the mask plate 423 for the left and right eyes, the image of the stereoscopic chart is shown to the subject. 416a' is presented. Figure 17 shows a stereoscopic chart image 416 with a parallax of 4'.
a' indicates the presented state. Step 6-2 and Step 6-4: The subject:
Among the charts presented, the answer switch 13 is used to answer whether the diamond-shaped image 419', which appears to stand out from the other diamond-shaped images 418 in stereoscopic vision, is located in the left, right, top, or bottom. 1st
In the example of FIG. 7, the diamond on the left appears to be floating, so the switch 21 is pressed.
CPU607 receives answers from the test subject and ROM6
The answer is compared with the answer stored in advance in 06, and it is determined whether the answer is correct or not. If the answer is correct, proceed to step 6-3. If the answer is incorrect, the process moves to step 6-4, where the printer 19 prints out the discrimination ability with a parallax of 4' or more, that is, level 0, and the test ends. Steps 6-3 to 6-15: Stereoscopic chart 416c with parallax 3',
Stereoscopic chart 416e for parallax 2', stereoscopic chart 416b for parallax 1', parallax 3
0'' stereoscopic charts 416d are presented sequentially depending on whether the examinee's answers are correct or incorrect, and level 1 is determined from the disparity value of the stereoscopic chart with the incorrect answer.
to level 4, and the result is printed by the printer 19. When the end switch 313 of the operation panel 30 is pressed to cancel an erroneous test during any of the above-mentioned tests, the CPU 607 cancels the subsequent test and returns to the initial state (step 1-1 in FIG. 9).
2). In addition, if there is a possibility that a person who is taking a test using this vision meter for the first time may not understand how to answer and may receive an incorrect test result, a "Practice" switch can be installed as shown by the broken line in Figure 3. By turning ON, a program is activated that presents the Landolt optotype with visual acuity of 0.1 in a binocular distance visual acuity test and allows the user to practice answering methods using the answer switch 13.

[Brief explanation of the drawing]

Fig. 1 is an external perspective view showing an embodiment of an automatic visual acuity meter according to the present invention, Fig. 2A is a plan view showing the configuration of an answer switch, and Fig. 2B is a B--B in Fig. 2A.
B' cross-sectional view, Figure 3 is a plan view showing the configuration of the operation panel, Figure 4 is a perspective view showing the optical arrangement, Figure 5 is a plan view showing the configuration of the auxiliary lens group, and Figure 6 is the liquid crystal panel. 7 is a plan view showing an example of a mask plate pattern, FIG. 8 is a block diagram showing the configuration of the electrical system, FIG. 9 is a flowchart showing the overall flow of the inspection routine, and FIG. Figure 10 is a flowchart showing the measurement processing subroutine, No. 11.
The figure is a flowchart showing a screening routine, Figures 12A to 12D are diagrams showing examples of visual target presentation, Figure 13 is a flowchart showing a subroutine for preventing erroneous measurements due to coincidence, and Figure 14 is a flowchart showing a subroutine for preventing erroneous measurements due to coincidence.
0.7 A flowchart showing a precision test subroutine. FIG. 15 is a flowchart showing a routine within each step common to each step in FIG. 14. FIG. 16 is a flowchart showing a stereoscopic vision test routine. FIG. 17 FIG. 3 is a diagram showing an example of stereoscopic presentation. 10...Pedestal, 11...Operation panel, 12...
Start switch, 13...Answer switch, 30
...Operation panel, 40R, 40L...Light source for illuminating the optotype board, 42R, 42L...Target board, 43R, 4
3L...Lens, 47R, 47L...Background light source, 48R, 48L...Diffusion plate.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) Two projection optical systems that project the light from the optotype plate independently to the right and left eyes of the subject, and the light that becomes the background light to the right and left eyes. Two background optical systems project independently to each eye, and when the projection optical system projects a visual target beam to one eye, the projection optical system projects the background beam to the other eye. A visual acuity meter comprising an optical system and a control system for controlling a background optical system. (2) Each of the projection optical meters includes a light source for transmitting illumination of the optotype plate, and a lens for projecting light from the optotype plate toward the eye to be examined, and Each of the background optical systems includes the background light source, a diffusion plate for converting the emitted light from the background light source into diffused light, and a half mirror for merging with the corresponding projection optical system. The visual acuity meter set forth in claim (1) of the utility model registration claim.