JP4705228B2 - Sight meter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a visual acuity meter, and more particularly to a visual acuity meter that can measure visual acuity in a situation of a background color different from normal.
[0002]
[Prior art]
Since it is necessary to quickly and accurately determine obstacles, signals, signs, and the like while driving a car, dynamic visual acuity is regarded as important and measurement is performed. In this case, dynamic visual acuity is the ability to see moving objects, that is, when you see things that are moving and stationary, or when you are stationary and seeing moving objects, or both are moving It is said that it is generally about 20-30% lower than static vision.
[0003]
Moreover, since the causes of traffic accidents increase due to a decrease in visual acuity at night, it is important to quantitatively measure how much visual acuity is at night. Therefore, a night vision test is performed to measure visual acuity under low illuminance after bright adaptation.
[0004]
[Problems to be solved by the invention]
Thus, in the past, vision meters that measure moving or night vision in addition to static vision have been proposed, but moving vision and night vision in the state of wearing sunglasses, that is, in a background color different from normal. No one has been proposed to measure
[0005]
Some visually handicapped people are difficult to adapt to darkness, and when these people move from outside to inside buildings, they will be unable to see anything for a while. In addition, people who work outdoors, such as athletes, may not be able to fully demonstrate their abilities due to glare. These people usually wear sunglasses that cut off a specific wavelength range, but the optimal color characteristics vary from person to person. For this reason, it was difficult to determine sunglasses suitable for individuals.
[0006]
The present invention has been made to solve such problems, and an object thereof is to provide a visual acuity meter capable of quantitatively measuring visual acuity at a specific wavelength light.
[0007]
[Means for Solving the Problems]
  The present invention that solves the above problems (Claim 1) includes a target display means for displaying a target, an eyepiece for observing the displayed target, and the size or direction of the target. And a means for setting a background color of the optotype, and selects one of a plurality of optotypes arranged along a circumference of a disc on which the optotype can rotate. Displayed byFurther, the background color is set by inserting one of a plurality of color filter units each having a different color filter into the optical path,It is characterized in that visual acuity can be measured by changing the background color of the target.In the invention of claim 8, the color filter unit that can be mounted by replacing color filters having different background color settings is inserted into the optical path.Thereby, the static visual acuity in a specific wavelength light can be measured.
[0008]
  In addition, the present invention(Claim 2)Is provided with means for changing the optical distance between the eyepiece and the visual target at a predetermined speed, whereby the background color and optical distance of the visual target can be changed. With such a configuration, it is possible to measure the dynamic visual acuity at a specific wavelength light.
[0009]
  In addition, the present invention(Claim 3)The illumination means for illuminating the subject's eyes for a predetermined time is provided, the background color of the target is changed, and after the subject's eyes are illuminated for a predetermined time, the set target is identified. Measure the time to do it. Such a configuration makes it possible to measure night vision at a specific wavelength.
[0010]
  Thus, the present invention(Claim 3)Now, it is possible to quantitatively measure the visual acuity at a specific wavelength of a visually impaired person who is weak in dark adaptation and feels inconvenient in daily life or who wants to reduce glare, It is effective in determining the optimal color characteristics of sunglasses.
  In the present invention (Claim 9), the setting is performed by inserting one of a plurality of color filter units, each having a different color filter set with a background color filter, into the optical path. A code for identifying the color of the color filter attached to the color filter unit is provided, and the color of the filter attached to the color filter unit inserted in the optical path is determined by reading the code; One of the color filter units is inserted into the optical path, and the visual acuity is measured by changing the background color of the target.
  In the present invention (Claim 10), the setting of the background color is performed by inserting a color filter unit that can be mounted by exchanging different color filters into the optical path, and mounting the different color filters on the color filter unit. The visual acuity is measured by changing the background color of the target.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.
[0012]
1A and 1B schematically show the front and side of a visual acuity meter according to an embodiment of the present invention. Reference numeral 1 denotes an eyepiece, and a subject can make contact with this eyepiece. A left eye is applied to the left eye 1a of the eye 1 and the right eye is applied to the right eye 1b to observe the target. The sight meter is provided with a dark curtain 3 that can expand and contract along the guide 2 so that the visual target can be observed favorably.
[0013]
An operation panel 5 as shown in detail in FIG. 2 is arranged on the side surface of the sight meter. The operation panel 5 is provided with a power switch 5a. When the power switch is turned on, the night vision measurement switch 5b, the moving object vision measurement switch 5b ', and the stationary vision measurement switch 5c are turned on. Furthermore, left eye, both eyes, and right eye selection switches 5d to 5f are provided, and by operating these switches, the left eye, both eyes, and the right eye of the eye to be examined can be brought into the target observation state. The visual target switches 5g to 5j are for switching the direction of the cuts of the known visual target (Landolt ring), and the visual acuity change switches 5m and 5n are for changing the visual target and changing the visual acuity value. The visual acuity value is displayed on the display unit 5q. The adaptation time display section 5p can display the progress of dark adaptation time.
[0014]
Further, the display panel 5 is provided with a lighting lamp 5x that displays an open or closed state of the eye to be examined, and a sensitivity adjustment button 5y that can change the detection sensitivity is disposed below the lighting lamp 5x. Further, a darkness filter of various densities can be inserted into the illumination optical path of the target by using the field density button 5k, whereby the background density of the target can be changed. The inserted filter density, that is, the target density, can be displayed on the display unit 5q 'as a glare output. When the density of the neutral density filter is high, a large glare output value is displayed.
[0015]
In addition, various color filters can be inserted into the illumination light path of the target by using the background color selection button 5r, thereby changing the background color of the target. Which color filter is selected is displayed by displaying the color of the filter on the display unit 5s.
[0016]
In FIG. 1A, what is indicated by reference numeral 6 is a response switch that is pressed when the subject recognizes the cut of the target and confirms the target.
[0017]
As shown in FIG. 1B, a printer connection terminal 7 for connecting a printer 65 as described later is provided on the side of the main body of the sight meter. It is possible to connect to a network computer 9 including a computer (PC) main body 9a, a monitor 9b, and a printer 9c in another network.
[0018]
FIG. 3A shows the optical arrangement of the vision meter and the arrangement of the control unit. In FIG. 3A, the left eye 10 and the right eye 10 ′ of the subject are the eyepiece 1a, It is located in front of the cover glasses 11, 11 ′ and shutters 12, 12 ′ arranged in 1b. When the left eye selection switch 5d is operated, the shutter 12 is operated by the CPU 40. When the right eye selection switch 5f is operated, the shutter 12 'is operated, and when the binocular selection switch 5e is further operated, both the shutters 12 and 12' are operated by the CPU 40. It is driven by the actuator 41 to be detached from the optical path.
[0019]
When the shutter 12 leaves the optical path, the target plate 17 disposed behind the reflective dome is passed through the window glass 16a of the reflective dome 16 through the mirrors 13 and 14, the half mirror 14 ', the movable prism 30, and the focusing lens 15. On the other hand, when the shutter 12 ′ is separated from the optical path, it is disposed behind the reflecting dome through the window glass 16 a of the reflecting dome 16 through the mirror 13 ′, the half mirror 14 ′, the movable prism 30 and the focusing lens 15. The observed target plate 17 can be observed.
[0020]
The movable prism 30 is moved at a predetermined speed along the optical path by a prism motor 33 controlled by the CPU 40, whereby the optical distance between the eyepiece and the visual target changes and is observed through the eyepiece. The size (magnification) of the target on the target plate changes according to the change. In this case, the moving speed can be changed in the range of 20 km / h to 60 km / h, for example.
[0021]
The reflection dome 16 is formed of a diffusive member inside, and is illuminated and diffusely illuminated by a moving object driven under the control of the CPU 40 or a dome illumination light source 42 for stationary vision. When the night vision is measured, the reflecting dome 16 is illuminated by using a dome illumination light source (halogen lamp) 46 for bright order in order to make the subject's eye brightly adapted.
[0022]
The target plate 17 has a shaft 17a coupled to a shaft of a stepping motor 43 driven by the CPU 40, and a plurality of Landolt rings formed around the target plate 17 as shown in FIG. 3B. The visual target 17b is arranged as a black pattern (not transmitting light) on the transmission diffusive disc. Each optotype is composed of four optotypes whose cuts differ by 90 degrees, and the size of each opposition is different according to the visual acuity value. One of them is driven by driving the stepping motor 43. It is moved to the window 16b of the reflective dome. In order to measure night vision, for example, a target corresponding to a vision value of 0.2 is covered with a diffusion plate 17c.
[0023]
Furthermore, each target is illuminated from behind via a half mirror 18 with a target illumination light source 44 driven under the control of the CPU 40 when measuring moving or static visual acuity, and the night vision is measured. In this case, the target illumination light source 45 for night vision driven similarly under the control of the CPU 40 is illuminated through the half mirror 18. In this case, each light source 44 and 45 can adjust the light quantity.
[0024]
Furthermore, the indicator illuminated by each light source is dimmed by the density adjustment disk 32 so that the background density can be adjusted. The shaft 32 'of the density adjusting disk 32 is coupled to the shaft of the stepping motor 31, and there are a plurality of neutral density filters (ND filters) having different densities as shown in FIG. ) Are arranged along the circumference. For example, the filter 32a is through and is not dimmed, and the density gradually increases clockwise in the figure, and the filter 32b has the highest density and the dimming is strong. Since the stepping motor 31 rotates 45 degrees each time the visual field density button 5k is pressed, a neutral density filter having different densities can be sequentially inserted into the illumination optical path in accordance with the pressing of the visual field density button 5k.
[0025]
Further, a color filter disk 61 is disposed between the half mirror 14 'and the movable prism 30 so that the background color of the visual target can be changed. The color filter disk 61 is configured to be rotated around its axis by a stepping motor 60 controlled by the CPU 40. Various color filters are provided around the color filter disk 61 as shown in FIG. For example, the filter 61a is through and has no background color, the filter 61b is an A color filter, the filter 61c is a B color filter, the filter 61d is a C color filter, and the filter 61e is a D color filter. The filter 61f is an E-color filter or the like, and is a filter that transmits a wavelength corresponding to each color. Since the stepping motor 60 rotates 45 degrees each time the background color selection button 5r is pressed, color filters having different colors can be sequentially inserted into the illumination optical path in accordance with the pressing of the background color selection button 5r. Each target is black, and its wavelength characteristic is not substantially changed by the insertion of the color filter, so that it can be changed according to the color of the color filter into which the background color of the target is substantially inserted.
[0026]
Further, each displayed target can be set to an optimum optical distance for eyesight measurement with respect to the eyepiece by adjusting the focusing lens 15, and an apparent target of 5 m can be formed. . In addition, in order to prevent the measurement from being disturbed by blinking during measurement, a light receiving element 47 for receiving reflected light from the eye to be illuminated illuminated by the dome illumination light source 46 for bright order application is provided. The signal is input to the CPU 40. When the eyelid closes and the amount of light incident on the light receiving element 47 decreases, the lamp 5x is turned on. Note that the sensitivity with which the eyelid is closed and the lamp 5x is turned on can be adjusted with the sensitivity adjustment button 5y.
[0027]
The CPU 40 is driven by a clock 50, and the memory 51 stores programs and data necessary for visual acuity inspection. The CPU 40 can take in signals from various switches or buttons arranged on the operation panel 5 or the response switch 6 via the interface 52, and can also input various data to the displays 5p, 5q, 5q ′, 5s to the lamp 5x. Can be displayed. Further, voice guidance for guiding the program progress can be output from the voice guidance unit 53. Measurement results and the like can be output to the printer 65.
[0028]
Next, the flow of measuring night vision and moving or stationary vision will be described with reference to the flowchart of FIG. This program is stored in the memory 51 and executed under the control of the CPU 40.
[0029]
First, in step S1, the power switch 5a is turned on. As a result, the night vision measurement switch 5b, the stationary vision measurement switch 5c, and the moving body vision measurement switch 5b ′ are turned on, and each vision measurement state is established.
[0030]
In step S2, when the night vision measurement switch 5b is pressed, night vision measurement is started. At this time, first, in step S3, the shutters 12, 12 'are separated from the optical path by the actuator 41. Night vision is usually measured with both eyes, but when measuring with either eye, the shutter corresponding to that is removed from the optical path. Further, in step S4, by driving the stepping motor 43, for example, a visual target having a cut in a predetermined direction corresponding to a visual acuity value of 0.2 is moved to the window 16b of the diffusion dome 16 together with the diffusion plate 17c thereon. . Further, by pushing the visual field density button 5k, the stepping motor 31 is driven and the density adjusting disk 32 is rotated, so that any one of the neutral density filters is inserted into the optical path. The density at this time, that is, the glare output value is displayed on the display 5q '.
[0031]
Further, by pushing the background color selection button 5r, the stepping motor 60 is driven, and by rotating the color filter disk 61, a predetermined color filter can be inserted into the optical path, and the background color of the target can be set. The color of the selected color filter at this time is displayed on the display 5s.
[0032]
At this time, the target illumination light source 45 for night vision is turned on in step S5, and the target is illuminated from behind (for example, illuminated with a dark luminance of 0.1 to 0.15 cd / square m).
[0033]
In the case of night vision measurement, since the subject's eye needs to be sufficiently brightly adapted, the dome illumination light source 46 of the bright order is turned on in step S6 to illuminate the dome and the subject's eye (for example, 5700 cd / square m). Lighting with brightness of). Since the light is adapted in about 30 seconds, the light source 46 is then turned off, and the response of the subject is waited in step S7. The subject is almost darkened by turning off the illumination light source 46, but the cut of the target displayed in accordance with dark adaptation can be confirmed. The subject responds with the response switch 6 when the cut of the target can be identified.
[0034]
The time until the response after the light source 46 is turned off is measured by a timer (not shown) in the CPU and displayed on the display 5p. This time quantitatively indicates the dark adaptability of the subject, that is, night vision, and is measured as night vision. In this case, since the glare output value is displayed on the display 5q ', it is possible to diagnose whether there is a glare sensitivity failure from the glare output value obtained in advance and the response time characteristic curve. Moreover, since the visual acuity value with the set background color can be measured, the night vision with the specific wavelength light can be quantitatively measured.
[0035]
It is to be noted that whether or not the eyelid of the eye to be examined is open while the illumination light source 46 is turned on and the eye to be examined is brightly adapted is measured using the light receiving element 47, and when the eye is closed by blinking or the like, the lamp 5x is Light up and inform the examiner of it.
[0036]
On the other hand, when the static visual acuity measurement switch 5c is selected in step S2, static visual acuity measurement is started. In step S13, the shutter 12 and / or 12 ′ or both are selected according to which eye is selected by the switches 5d to 5f. Is removed from the optical path. In step S <b> 14, the target is illuminated with the target illumination light source 44, and the reflective dome 16 is illuminated with the dome illumination light source 42. When a visual target corresponding to a predetermined visual acuity value is set using the visual acuity change switches 5m and 5n and the visual target switches 5g to 5j in step S15, the step target motor 43 rotates and the selected visual target is displayed in the window 16b. Moving. Further, by pushing the visual field density button 5k, the stepping motor 31 is driven and the density adjusting disk 32 is rotated, whereby any one of the neutral density filters is inserted into the optical path. The density at this time, that is, the glare output value is displayed on the display 5q ', and the visual acuity value set at this time is displayed on the display 5q.
[0037]
Similarly, the stepping motor 60 is driven by pressing the background color selection button 5r, and a predetermined color filter is inserted into the optical path by rotating the color filter disk 61, thereby setting the background color of the target. The color of the selected color filter at this time is displayed on the display 5s.
[0038]
If the subject can confirm the target, the response is made with the response switch 6 (step S16). If the target cannot be confirmed, the subject returns to step S15 and the subject switches the target switches 5g to 5j or the visual acuity change switches 5m, 5n. Or the background density of the visual field is changed by pressing the visual field density button 5k or the background color of the visual target is changed by pressing the background color selection button 5r, and this is repeated. When there is a response, the value displayed on the display 5q is measured as a static visual acuity (step S17). In this case, since the glare output value is displayed on the display 5q ', it is possible to diagnose whether there is a glare sensitivity failure from the characteristic curve of the glare output value and the static visual acuity value obtained in advance. Moreover, since the visual acuity value with the set background color can be measured, the static visual acuity with the specific wavelength light can be quantitatively measured.
[0039]
In addition, when the moving object visual acuity measurement switch 5b ′ is selected in step S2, the moving object visual acuity measurement is started. Both are removed from the optical path. In step S 24, the target is illuminated with the target illumination light source 44, and the reflective dome 16 is illuminated with the dome illumination light source 42. In step S25, a visual target corresponding to a predetermined visual acuity value is set using the visual acuity change switches 5m and 5n and the visual target switches 5g to 5j. Then, according to the set value, the stepping motor 43 rotates and the selected target moves to the window 16b. Further, when the visual field density button 5k is pressed, the stepping motor 31 is driven to rotate the density adjustment disk 32, whereby any one of the neutral density filters is inserted into the optical path. The density at this time, that is, the glare output value is displayed on the display 5q '.
[0040]
Similarly, the stepping motor 60 is driven by pressing the background color selection button 5r, and a predetermined color filter is inserted into the optical path by rotating the color filter disk 61, thereby setting the background color of the target. The color of the selected color filter at this time is displayed on the display 5s.
[0041]
Subsequently, in step S26, the movable prism 30 is moved to change the optical distance between the eyepiece and the visual target, thereby changing the magnification of the visual target. The subject observes the ring of the target that gradually increases through the eyepiece, and responds with the response switch 6 when the direction in which the ring is broken is known (step S27). The CPU 40 calculates the moving visual acuity based on the position of the prism 30 at this time from this information taken in via the interface 52 (step S28), and displays it on the display 5q. In this case, since the glare output value is displayed on the display 5q ', it is possible to diagnose whether there is a glare sensitivity failure from the characteristic curve of the glare output value and the dynamic visual acuity value obtained in advance. In addition, since the visual acuity value with the set background color can be measured, the dynamic visual acuity with the specific wavelength light can be quantitatively measured.
[0042]
If there is no response from the response switch 6 during the above-mentioned night vision or moving body vision measurement, the measurement can be advanced by changing the measurement program such as automatically changing the vision value. Further, when the eyelid is closed during the night vision measurement, it is possible to notify the examiner of that fact by the lamp 5x or to inform the examiner and the subject by voice. Further, when the eyelid is closed, the measurement program can be changed so that the detection level for automatically detecting that the eyelid is closed is changed and the measurement is performed again. Further, the progress of each measurement or the like can be output as needed by the voice guidance 53, and the subject can be guided by voice according to a preset program.
[0043]
In the above-mentioned stationary, moving and night vision measurement, when the background color of the target is changed, the background density of the target becomes deep and it becomes difficult to measure the visual acuity at the predetermined background color, or purely the background In order to measure the influence of color, the background density of the target is set to 0, that is, the through filter 32a is selected with the density adjustment disk 32, and various background colors are selected with the background color selection button. The visual acuity is measured by changing the size or direction of the visual target in the background color.
[0044]
In FIG. 5, for example, a target with a cut in a predetermined direction corresponding to a visual acuity value of 0.2 has no background density (the through filter 32a is selected), and the color filters 61b to 61f are selected. The response time is shown, which can be printed via the printer 65, for example, or transferred to another computer 9a on the network and printed out by the printer 9c connected thereto.
[0045]
In the above-described embodiment, since the number of color filters that can be arranged on the color filter disk 61 is limited, it is difficult to use various color filters. Therefore, various color filters can be used instead of the color filter disk. An embodiment using this will be described with reference to FIG.
[0046]
In this embodiment, as shown in FIG. 6A, the eyepiece 1 is provided with a filter insertion groove 1c, and the insertion groove 1c has an A color filter 70a and a B color filter 71a, C, respectively. The color filter units 70, 71, 72,. . . . . Can be inserted, and the wavelength characteristics of the light incident on the left eye 1a and the right eye 1b can be changed. Each target is black, and its wavelength characteristic is not substantially changed by the insertion of the color filter unit. Therefore, the target can be changed according to the color of the color filter into which the background color of the target is inserted.
[0047]
In this case, in order to identify the color filter of the inserted color filter unit, each color filter unit is provided with a color identification code as shown in FIGS. . In the example shown in FIG. 6B, the color filter 70a of the color filter unit 70 is provided with a plurality of small windows 70b in the lower part that can block light or switch light, and each small window is blocked by a small window (black). The color of the color filter is coded by using a small window or a transparent small window (white mark).
[0048]
In the example shown in FIG. 6C, a mark 70c having a reflectance different from that of the main body of the color filter unit 70 is attached. In the example shown in FIG. 70d is provided to code the color of the color filter. These color codes are read by the read color code discriminating means 80 that optically reads the color codes as shown by dotted lines in FIG. 3, and the CPU 40 recognizes the target background color set.
[0049]
In the above-described embodiment, a plurality of color filter units are provided. However, as shown in FIG. 6E, a plurality of color filters 91, 92, 93,. . . . . It is also possible to set the background color of the visual target using a single color filter unit 90 that can be mounted by exchanging. The color filter unit 90 can be inserted into the insertion groove 1 c of the eyepiece 1, and the color filter unit 90 is formed with a transmission portion 90 a, and various color filters 91, 92, 93,. . . . . An insertion groove 90b is formed in which can be inserted. When it is desired to set a desired background color, a color filter having the same color as the background color to be set is attached to the color filter unit 90. As a result, a color filter of that color appears in the transmissive part 90a, so that the background color of the visual target can be set to the color filter color by inserting the color filter unit 90 into the insertion groove 1c of the eyepiece part 1. it can. Also by this method, the same effect as that of the embodiment shown in FIG.
[0050]
Further, as in the embodiment illustrated in FIG. 7A, for example, a color filter unit 100 equipped with an A color filter 100a, and a density filter having a predetermined density for changing the background density of A color. The density filter units 100 ′ fitted with 100a ′ may be stacked as a set and inserted into the filter insertion groove 1c of the eyepiece 1. When changing the density of the A color to a different density, the density filter unit to which the density filter of another density is attached and the color filter unit 100 to which the A color filter 100a is attached may be combined. When it is desired to create a background color having a predetermined density of a certain color, a filter unit with a filter of another color and a density filter unit with a density filter of a predetermined density are inserted into the filter insertion groove 1c as a set. . In the case of this embodiment, the color filter disk 61 and the density adjustment disk 32 can be omitted, and the number of background colors and background densities is made larger than that which can be realized by the color filter disk 61 and the density adjustment disk 32. It is possible to measure visual acuity with various background colors having various densities.
[0051]
Further, as shown in FIG. 7B, using a single filter unit 110 having a transmission part 110a and an insertion groove 110b, a color filter 120 of a predetermined color and a density filter 120 'of a predetermined density are provided. Alternatively, the filter unit 110 may be inserted into the insertion groove 1 c of the eyepiece 1 by inserting the filter unit 110 into the insertion groove 110 b. When it is desired to set a desired background color at a desired density, a color filter having the same color as the background color to be set and a density filter having the density to be set are combined and attached to the filter unit 110. Also in the embodiment shown in FIG. 7B, the same effect as that in the embodiment shown in FIG. 7A can be obtained.
[0052]
【The invention's effect】
As described above, according to the present invention, the visual acuity can be measured by setting various background colors of the visual target, so that the visual acuity with a specific wavelength light can be quantitatively measured.
[Brief description of the drawings]
FIG. 1A is a front view of a sight meter according to an embodiment of the present invention, and FIG. 1B is a side view thereof.
FIG. 2 is a layout diagram illustrating a layout of various switches on an operation panel.
3A is a configuration diagram showing the configuration of an optical system and a control system of a vision meter, FIG. 3B is a front view of a target plate, FIG. 3C is a front view of a density adjustment disk, and FIG. ) Is a front view of the color filter disk.
FIG. 4 is a flowchart showing a flow of visual acuity measurement.
FIG. 5 is a diagram showing a result of measuring visual acuity (response time) by changing a color filter;
FIG. 6 is an explanatory diagram showing another embodiment for selecting a color filter.
FIG. 7 is an explanatory diagram showing another embodiment for selecting a color filter and a density filter.
[Explanation of symbols]
6 Response switch
12, 12 'shutter
16 Diffusion dome
17 Target plate
30 Movable prism
32 Density adjustment disc
61 color filter disc
70, 71, 72 color filter unit

Claims (10)

A target display means for displaying the target;
An eyepiece for observing the displayed target;
Means for setting the size or direction of the target;
Means for setting a background color of the target;
One of a plurality of color filter units, each of which is displayed by selecting one of a plurality of targets arranged along the circumference of a rotatable disc , and each having a different color filter. A visual acuity meter capable of measuring the visual acuity by changing the background color of the visual target by setting the background color by inserting the light into the optical path . A target display means for displaying the target;
An eyepiece for observing the displayed target;
Means for setting the size or direction of the target;
Means for setting a background color of the target;
Means for changing the optical distance between the eyepiece and the visual target at a predetermined speed,
The visual target is displayed by selecting one of a plurality of visual targets arranged along the circumference of a rotatable disc, and the visual acuity can be measured by changing the background color of the visual target and the optical distance. Sight meter characterized by. A target display means for displaying the target;
An eyepiece for observing the displayed target;
Means for setting the size or direction of the target;
Means for setting a background color of the target;
Illuminating means for illuminating the subject's eyes for a predetermined time,
The target is displayed by selecting one of a plurality of targets arranged along the circumference of a rotatable disc,
A visual acuity meter that measures visual acuity by changing a background color of a visual target, illuminating a subject's eyes for a predetermined time, and measuring a time until the set visual target can be identified.   The sight meter according to claim 1, wherein the target is a Landolt ring. The background color is set by selecting a color filter corresponding to one of the different background colors arranged along the periphery of the rotatable disc and inserting the color filter into the optical path. The visual acuity meter according to claim 2 or 3 , wherein 4. The visual acuity meter according to claim 2, wherein the background color is set by inserting one of a plurality of color filter units each having a different color filter into the optical path. Each color filter unit is provided with a code that can identify how many color filters are attached to the unit, and the color of the filter attached to the color filter unit inserted in the optical path reads the code. The visual acuity meter according to claim 1 or 6, characterized in that the visual acuity is discriminated. A target display means for displaying the target ;
An eyepiece for observing the displayed target ;
Means for setting the size or direction of the target;
Means for setting a background color of the target;
A color filter unit that is displayed by selecting one of a plurality of targets arranged along the circumference of a rotatable disc and that can be mounted by exchanging different color filters in the optical path. A visual acuity meter capable of measuring the visual acuity by changing the background color of the target by setting the background color by being inserted into the visual field. A target display means for displaying the target;
An eyepiece for observing the displayed target;
Means for setting the size or direction of the target;
Means for setting a background color of the target;
The setting of the background color is performed by inserting one of a plurality of color filter units equipped with different color filters into the optical path,
Each color filter unit is provided with a code that can identify how many color filters are mounted on the color filter unit, and the color of the filter mounted on the color filter unit inserted in the optical path reads the code. Is determined by
A visual acuity meter capable of measuring visual acuity by inserting one of the plurality of color filter units into an optical path and changing a background color of a visual target. A target display means for displaying the target;
An eyepiece for observing the displayed target;
Means for setting the size or direction of the target;
Means for setting a background color of the target;
The setting of the background color is performed by inserting a color filter unit that can be mounted by exchanging different color filters into the optical path,
A visual acuity meter, wherein a different color filter is attached to the color filter unit, and the visual acuity can be measured by changing the background color of the visual target.

Images