Visual inspection method, visual inspection system, and visual inspection program

Abstract

This visual inspection system comprises: a visual acuity inspection image presentation unit that presents, to a subject, a visual acuity inspection image including a visual target for measuring the visual acuity of the subject and a background region around the visual target; a visual acuity inspection image changing unit that changes at least one of the luminance or hue of the visual acuity inspection image; and a visual acuity measurement unit that measures the visual acuity of the subject by inspecting whether the subject can recognize the visual target when viewing the visual acuity inspection image.

Description

Visual inspection method, visual inspection system, and visual inspection program

[0001] The present invention relates to a visual inspection method, a visual inspection system, and a visual inspection program.

[0002] Human visual characteristics include visual acuity, which is the ability to recognize the presence and shape of objects and images, luminance sensitivity, and color vision, which indicates sensitivity to color. These visual characteristics vary from person to person and also change with age, environment, and other factors. Known disorders related to human visual characteristics include vision-related disorders such as myopia, presbyopia, and astigmatism; luminance-related disorders such as photosensitivity, which makes certain wavelengths of light dazzling; and color vision-related disorders such as color blindness and color weakness, which cause low sensitivity to light in certain wavelength bands. Decreased visual acuity can be corrected with glasses or contact lenses. Luminance and color vision disorders can be alleviated by using optical filters with adjusted light transmission characteristics.

[0003] Methods for testing human visual characteristics have been known for some time. Visual acuity can be tested by examining whether a subject can recognize the shapes of optotypes of various sizes (e.g., Landolt rings). A method for testing and correcting color vision characteristics is disclosed, for example, in Japanese Patent Laid-Open Publication No. 6-18819 (hereinafter referred to as Patent Document 1). In Patent Document 1, color vision characteristics are classified into 32 types based on the color vision characteristic test results of multiple patients. The color vision characteristics of the subject to be tested are then tested to determine which of the 32 types of color vision characteristics they fall into. The subject's color vision deficiency is alleviated by using an optical filter whose characteristics are determined based on the test results.

[0004] Japanese Unexamined Patent Publication No. 6-18819

[0005] The color vision testing method described in Patent Document 1 determines which of predetermined categories the subject's color vision characteristics fall into. Therefore, there is a problem that accurate test results cannot be obtained for subjects whose color vision characteristics do not fall into any of the predetermined categories or for subjects whose color vision characteristics are intermediate between multiple categories. Furthermore, the color vision testing method described in Patent Document 1 alleviates the subject's color vision characteristics, but does not correct their eyesight.

[0006] Furthermore, if a subject has photosensitivity, it may be difficult for the subject to see the optotype used to test their visual acuity, and their visual acuity may not be measured accurately. Furthermore, if a subject has color weakness or color blindness, they may have difficulty recognizing the color of the optotype, and their visual acuity may not be measured accurately. Therefore, even if the subject's visual acuity, the luminance of the optotype, and sensitivity to color are tested separately, the subject's visual acuity cannot be accurately tested, and the subject's visual acuity cannot be appropriately corrected.

[0007] The present invention has been made in consideration of the above circumstances, and its purpose is to provide a visual testing method, a visual testing system, and a visual testing program that can test the subject's visual acuity more accurately.

[0008] A visual acuity testing method for visual characteristics according to one embodiment of the present invention is a visual acuity testing method for measuring the visual acuity of a subject using a test image. Types of test images include visual acuity test images, which include a visual target for measuring the visual acuity of the subject and a background area surrounding the visual target, with the visual target having a color different from that of the background area. The visual acuity testing method includes a visual acuity test image presenting step of presenting the visual acuity test image to the subject, a visual acuity test image modifying step of modifying at least one of the brightness and color of the visual acuity test image, and a visual acuity measuring step of measuring the visual acuity of the subject by testing whether the subject can recognize the visual target when viewing the visual acuity test image.

[0009] A visual characteristics visual testing program according to one embodiment of the present invention causes a computer to execute a method including: a visual acuity test image presenting step of presenting to a subject a visual acuity test image including a visual target for measuring the visual acuity of the subject and a background area surrounding the visual target, wherein the visual target has a color different from the color of the background area; a visual acuity test image modifying step of modifying at least one of the brightness and color of the visual acuity test image; and a visual acuity measuring step of measuring the visual acuity of the subject by testing whether the subject can recognize the visual target when looking at the visual acuity test image.

[0010] A visual testing system for visual characteristics according to one embodiment of the present invention is a visual testing system that measures the visual acuity of a subject using test images. Types of test images include visual acuity test images, which include a visual target for measuring the visual acuity of the subject and a background area around the visual target, the visual target having a color different from that of the background area. The visual testing system includes a visual acuity test image presenting unit that presents the visual acuity test image to the subject, a visual acuity test image modifying unit that modifies at least one of the brightness and color of the visual acuity test image, and a visual acuity measuring unit that measures the visual acuity of the subject by testing whether the subject can recognize the visual target when viewing the visual acuity test image.

[0011] According to the embodiments of the present invention, a visual inspection method, a visual inspection system, and a visual inspection program are provided that are capable of more accurately inspecting the visual acuity of a subject.

[0012] FIG. 1 is a schematic diagram of a visual inspection system according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of the absorption spectra of human cone cells (S cone cells, M cone cells, and L cone cells) and rod cells. FIG. 3 is a diagram showing human photopic vision and scotopic vision. FIG. 4 is a diagram showing an example of a sensitivity test image according to an embodiment of the present invention. FIG. 5 is a diagram showing an example of a visual acuity test image according to an embodiment of the present invention. FIG. 6 is a flowchart of a visual inspection method according to an embodiment of the present invention. FIG. 7 is a diagram showing an example of a correction filter according to an embodiment of the present invention. FIG. 8 is a diagram showing the bandwidth of a correction filter according to an embodiment of the present invention. FIG. 9 is a diagram showing an example of the characteristics of a correction filter according to an embodiment of the present invention. FIG. 10 is a diagram showing an example of the characteristics of a correction filter according to an embodiment of the present invention. FIG. 11 is a diagram showing an example of the characteristics of a correction filter according to an embodiment of the present invention. FIG. 12 is a schematic diagram of a visual inspection system according to a modified embodiment of the present invention. FIG. 13 is a front view of an eye chart according to a modified embodiment of the present invention. FIG. 14 is a schematic diagram of a visual inspection system according to a modified embodiment of the present invention. FIG. 15 is a schematic diagram of a visual inspection system according to a modified embodiment of the present invention. FIG. 16 is a schematic diagram of a visual inspection system according to a modified embodiment of the present invention.

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0014] [Visual Inspection System] Fig. 1 is a schematic diagram of a visual inspection system 1 that performs a visual inspection in one embodiment of the present invention. The visual inspection system 1 is used to inspect the visual characteristics of a subject 2. The visual characteristics include visual acuity, color vision characteristics, and characteristics related to brightness. The visual inspection system 1 includes a display device 10, a phoropter 20, a control unit 30, and an operation unit 40.

[0015] The display device 10 is, for example, a liquid crystal display or a CRT (Cathode Ray Tube) display. The display device 10 displays test images such as a sensitivity test image 110 and a visual acuity test image 120. The display device 10 is not limited to a device that displays an image in response to an image signal, such as a liquid crystal display, as long as it can show the test image to the subject 2. For example, the display device 10 may include a film on which the test image is printed and a backlight that irradiates the film with illumination light, and present the test image to the subject 2 by irradiating the film with the illumination light. The test image may also be printed on paper or a board.

[0016] A known phoropter 20 is disposed between the subject 2 and the display device 10. The phoropter 20 is used to measure the subject's 2 visual acuity, degree of astigmatism, direction of the astigmatism axis, etc. An examiner who tests the visual characteristics attaches trial lenses 21 with different powers and degrees of astigmatism correction to the phoropter 20, and the subject 2 views a visual acuity test image 120 through the trial lenses 21. The subject 2 then views the visual acuity test image 120, thereby enabling the subject's 2 visual acuity and degree of astigmatism to be tested. The phoropter 20 is an example of a visual acuity measurement unit. The visual acuity test image 120 is an example of a visual acuity test image.

[0017] The control unit 30 includes a CPU 31, a memory area 32, and an image signal generation unit 33. The memory area 32 stores an inspection program used in the visual inspection and data on an inspection image to be displayed on the display device 10. The CPU 31 causes the image signal generation unit 33 to output an image signal for the inspection image based on the inspection image data stored in the memory area 32. The display device 10 displays the inspection image in accordance with the image signal output from the control unit 30. The operation unit 40 is operated by the inspector and accepts operations to specify or change the inspection image to be displayed on the display device 10. The CPU 31 is an example of a computer. The display device 10 is an example of a visual acuity inspection image presenting unit and a sensitivity inspection image presenting unit, and the control unit 30 is an example of a visual acuity inspection image changing unit and a sensitivity inspection image changing unit. The control unit 30 is also an example of a condition acquisition unit.

[0018] In a visual test, the examiner operates the operation unit 40 to sequentially display multiple test images on the display device 10. The subject 2 views the test images through the phoropter 20. The subject 2 is then tested to see how dazzling the sensitivity test image 110 is (i.e., the subject 2's level of photosensitivity), how the subject 2 perceives the color of the sensitivity test image 110 (i.e., the subject 2's color vision), and whether the subject 2 can recognize the presence and shape of the optotype 121 included in the visual acuity test image 120 (i.e., the subject 2's visual acuity). The test results may be stored in the memory area 32. These tests are preferably performed in a darkroom to prevent external light from illuminating the test image and hindering accurate testing. Alternatively, a cover (e.g., a curtain, cover, etc.) that blocks external light may be placed around the display device 10. The sensitivity test image 110 is an example of a sensitivity test image.

[0019] When the visual characteristics of the subject 2 are tested by a visual test, a correction filter that corrects the visual characteristics of the subject can be created based on the test results. This correction filter corrects the visual acuity of the subject 2. Furthermore, if the subject 2 has photosensitivity, color weakness, or color blindness, the correction filter not only corrects the subject's visual acuity but also makes corrections to reduce the effects of the photosensitivity, color weakness, or color blindness on the visual acuity of the subject 2.

[0020] Figure 2 shows an example of the absorption spectra of human cone cells (S cone cells, M cone cells, and L cone cells) and rod cells. The horizontal axis of Figure 2 represents the wavelength of light, and the vertical axis represents the absorption rate of each cone cell and rod cell. "S," "M," "L," and "Rod" in Figure 2 represent the absorption spectra of S cone cells, M cone cells, L cone cells, and rod cells, respectively. Each absorption spectrum shown in Figure 2 is normalized by the maximum absorption rate. The higher the absorption rate of each cone cell and rod cell, the higher its sensitivity (susceptibility) to that light. S cone cells have maximum sensitivity around 420 nm. M cone cells have maximum sensitivity around 534 nm. L cone cells have maximum sensitivity around 564 nm. Rod cells have maximum sensitivity around 498 nm. Note that the wavelengths at which each cone cell and rod cell is most sensitive vary from person to person.

[0021] FIG. 3 shows human photopic and scotopic vision. The horizontal axis of FIG. 3 represents the wavelength of light, and the vertical axis represents the human sensitivity to each wavelength. Furthermore, photopic vision is represented by a solid line, and scotopic vision by a dashed line. Human sensitivity to light differs between bright and dark places. Because photopic vision is primarily performed by cone cells, it is believed that in bright places, humans recognize color using M and L cone cells, while the remaining S cone cells recognize the brightness of light. On the other hand, because scotopic vision is primarily performed by rod cells, it is believed that in dark places, humans recognize the brightness of light using these rod cells. Therefore, people with high sensitivity of S cone cells and rod cells, which are used to recognize the brightness of light, experience symptoms of photosensitivity, in which light is perceived as dazzling. Furthermore, people with a difference in the sensitivity of M cone cells and L cone cells, which are used to recognize color (i.e., sensitivity to green light and sensitivity to red light), experience symptoms of color weakness and color blindness. Color weakness includes, for example, type 1 color weakness, which is a condition in which the sensitivity to red light is low, and type 2 color weakness, which is a condition in which the sensitivity to green light is low.

[0022] [Sensitivity Test Image Set] Next, a sensitivity test image set will be described. The sensitivity test image set is a set of a plurality of sensitivity test images 110 displayed on the display device 10. Fig. 4 shows an example of the sensitivity test image 110.

[0023] The sensitivity inspection image 110 has an inspection area 111 arranged near the center of the sensitivity inspection image 110, and a peripheral area 112 arranged around the inspection area 111. In FIG. 4, the inspection area 111 is an area surrounded by a dashed line. This dashed line is drawn for the purpose of explaining the inspection area 120 and is not included in the sensitivity inspection image 110. The inspection area 111 and the peripheral area 112 have different colors. In the example shown in FIG. 4, the peripheral area 112 has a circular shape. Furthermore, an outer area 140 further outside the peripheral area 112 is black.

[0024] The inspection area 111 is an area corresponding to the fovea centralis on a human retina. The size of the inspection area 111 is set so that light emitted from the inspection area 111 forms an image within the fovea centralis. For example, the size of the inspection area 111 is determined by the apex angle θ of a cone with the inspection area 111 as the base and the eye of the subject 2 as the apex. IN (See FIG. 1) is set to be approximately 2 degrees. IN corresponds to the width of the visual field (i.e., the visual field angle) of the fovea. The diameter of the inspection area 111 varies depending on the distance between the subject 2 and the display device 10 of the visual inspection system 1. The size of the inspection area 111 only needs to be set so that the light emitted from the inspection area 111 is imaged within the fovea, and the apex angle θ IN The apex angle θ does not have to be exactly 2 degrees. IN may be greater or less than 2 degrees.

[0025] The peripheral region 112 corresponds to the region around the fovea centralis on the human retina. The size of the peripheral region 112 is set so that light emitted from the peripheral region 112 forms an image outside the fovea centralis on the human retina. For example, the size of the peripheral region 112 is determined by the apex angle θ of a cone with the peripheral region 112 as the base and the eye of the subject 2 as the apex. OUT (See FIG. 1) is set to be approximately 40 degrees (See FIG. 1). When the fovea is set to the center of the visual field (0 degrees), rod cells are mostly located around ±20 degrees. Therefore, the peripheral region 112 is set to have an apex angle θ OUTIt is desirable that the angle between the inspection area 111 and the peripheral area 112 is set to 40 degrees or more. The shape of the peripheral area 112 is not limited to a circle. If the display screen of the display device 10 is rectangular, the entire area of ​​the display screen other than the inspection area 111 may be the peripheral area 112.

[0026] The fovea of ​​the human retina contains many M cone cells, which are sensitive to green light, and many L cone cells, which are sensitive to red light. The fovea also contains very few S cone cells and rod cells. On the other hand, the area outside the fovea contains S, M, and L cone cells and rod cells.

[0027] Human visual acuity improves when the fovea is used. When viewing objects, images, or text, people primarily use the M and L cone cells located in the fovea to recognize the shape and color of the object. In other words, people can recognize color using only the M and L cone cells. Furthermore, people recognize not only color but also brightness by using the S and M cone cells and rod cells around the fovea. Therefore, it is possible to test a person's color vision by conducting a visual test targeting the M and L cone cells in the fovea. Furthermore, it is possible to test the degree of light sensitivity by conducting a test targeting the fovea and the S cone cells and rod cells around the fovea.

[0028] The test region 111 is an area used to test color vision using M and L cone cells in the fovea. The color of the test region 111 differs from the color of the peripheral region 112 in at least one of the R, G, and B components in the RGB color space. In this embodiment, the peripheral region 112 is achromatic. That is, the magnitudes of the R, G, and B components in the RGB color space are the same in the peripheral region 112. This is because if a chromatic color were used in the peripheral region 112, the color of the peripheral region 112 could affect the color vision test using the test region 111. The color of the peripheral region 112 must include a color to which rod cells are sensitive. For example, the color of the peripheral region 112 is a color other than black (i.e., the magnitudes of the R, G, and B components are zero). The color of the peripheral region 112 may also be white. The peripheral region 112 does not need to be a uniform color throughout, and may include areas of relatively low and high brightness.

[0029] The sensitivity test image set includes a plurality of sensitivity test images 110 whose test regions 111 or peripheral regions 112 have different colors. As an example, in this embodiment, the sensitivity test image set includes 345 types of sensitivity test images 110 whose colors are different from one another. Specifically, the set includes 115 types of sensitivity test images 110B whose blue component colors are different from one another, 115 types of sensitivity test images 110R whose red component colors are different from one another, and 115 types of sensitivity test images 110G whose green component colors are different from one another, relative to the peripheral region 112. The sensitivity test image 110B is a sensitivity test image for testing the sensitivity of the subject 2 to blue light. The sensitivity test image 110R is a sensitivity test image for testing the sensitivity of the subject 2 to red light. The sensitivity test image 110G is a sensitivity test image for testing the sensitivity of the subject 2 to green light.

[0030] The colors of the plurality of sensitivity test images 110B, each having a different color of the peripheral region 112, are set so that the brightness of the peripheral region 112 changes in increments of 5% or 10%, for example. The colors of the plurality of sensitivity test images 110G, each having a different color of the peripheral region 112, are set so that the brightness of the peripheral region 112 changes in increments of 5% or 10%, for example. The colors of the plurality of sensitivity test images 110R, each having a different color of the peripheral region 112, are set so that the brightness of the peripheral region 112 changes in increments of 5% or 10%. Note that the increments of the brightness of the peripheral region 112 are not limited to 5% or 10%, and may be continuously variable, for example.

[0031] Since the sensitivity test image 110 is displayed on the display device 10, the sensitivity test image 110 is displayed after undergoing gamma correction according to the gamma value of the display device 10. In more detail, when the input value of the image signal input to the display device 10 is x, the output value (luminance) is y, and the gamma value of the display device 10 is γ, y=x γ Therefore, the input value for changing the luminance y on the display device 10 is x=y １／γ In this embodiment, the RGB components of the sensitivity inspection image 110 are input values ​​(xR, xG, xB) to the display device 10, and each input value is expressed in 256 gradations from 0 to 255. The RGB components of the peripheral region 112 are calculated by the input values ​​(xR ＢＧ , xG ＢＧ , xB ＢＧ ) and each input value is expressed in 256 gradations from 0 to 255.

[0032] Table 1 shows the input values ​​(xR ＢＧ , xG ＢＧ , xB ＢＧ ) and the input values ​​(xR, xG, xB) of the inspection area 111.

[0033]

[0034] The "brightness [%] of the surrounding area" in Table 1 represents the brightness when the brightness when the surrounding area 112 is white (i.e., the input value is (255, 255, 255)) is set to 100%. The "color component of the surrounding area" represents the input value (xR ＢＧ , xG ＢＧ , xB ＢＧ ) are shown. In this embodiment, there are 11 types of surrounding regions 112B (5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100%). In this embodiment, the surrounding regions 112B are achromatic, so the RGB color components in each surrounding region 112B have the same size.

[0035] The "difference [%] of the blue component of the figure from the surrounding region" in the table represents the difference in the luminance of the blue component of the inspection region 111 from the luminance of the blue component of the surrounding region 112, assuming that the luminance of the blue component of the surrounding region 112 is 100%. In this embodiment, there are 12 different values ​​for the difference [%] of the blue component of the inspection region 111 from the surrounding region 112, in increments of 10%, ranging from -60% to +60%. Note that in this embodiment, the size of the red and green components of the surrounding region 112 is the same as the size of the red and green components of the inspection region 111, respectively. Therefore, when the difference in the blue component of the inspection region 111 from the surrounding region 112 is 0%, the inspection region 111 and the surrounding region 112 are the same color, and therefore are not included in the sensitivity inspection image 110B.

[0036] A sensitivity inspection image 110B is a combination of a peripheral region 112 and an inspection region 111 having an input value written in the same column as the peripheral region 112. For example, there are six types of sensitivity inspection images 110B in which the input values ​​of the peripheral region 112 are (255, 255, 255), and the red and green components of the inspection region 111 of these six types of sensitivity inspection images 110B are the same size as the red and green components of the peripheral region 112 (i.e., both are 255). Furthermore, the blue input values ​​of the inspection region 111 of these six types of sensitivity inspection images 110B are set so that their brightness changes in 10% increments from -60% to -10% relative to the blue input value of the peripheral region 112. The input values ​​of blue in the inspection area 111 of the six types of sensitivity inspection images 110B in which the input values ​​of the peripheral area 112 are (255, 255, 255) are 168, 186, 202, 217, 230, and 243, respectively.

[0037] In Table 1, when the input value of the surrounding area 112 is (255, 255, 255), the input value of the inspection area 111 where the difference [%] of the blue component from the surrounding area 112 is +10% or more is not listed because the maximum blue input value of the inspection area 111 is 255. Similarly, when the color components of the surrounding area 112 are (243, 243, 243), (230, 230, 230), or (217, 217, 217), no cases where the blue input value exceeds 255 are listed.

[0038] When the difference [%] of the blue component of the inspection area 111 from the surrounding area 112 is a positive value (+10% to +60), the magnitude of the blue component is greater than the red and green components, and therefore the inspection area 111 has a bluish color. The greater the difference [%] of the blue component from the surrounding area 112, the stronger the blueness, and the more distinct the color difference between the inspection area 111 and the surrounding area 112. On the other hand, when the difference [%] of the blue component of the inspection area 111 from the surrounding area 112 is a negative value (-10% to -60), the red and green components are greater than the blue component, and therefore the inspection area 111 has a yellowish color (a color with strong greenish and reddish hues). The smaller the difference [%] of the blue component from the surrounding area 112, the stronger the yellowness, and the more distinct the color difference between the inspection area 111 and the surrounding area 112.

[0039] A subject 2 with normal color vision can easily recognize the color difference between the test area 111 and the surrounding area 112 even when the absolute value of the difference [%] of the blue component from the surrounding area 112 is small. On the other hand, in order for a subject 2 with relatively low sensitivity to blue light to recognize the color difference between the test area 111 and the surrounding area 112, the absolute value of the difference [%] of the blue component from the surrounding area 112 needs to be large. A subject 2 with normal color vision can recognize the test area 111 within the surrounding area 112, for example, when the absolute value of the difference [%] of the blue component from the surrounding area 112 is 30% or more (i.e., −30% or less or +30% or more). On the other hand, subject 2 who has low sensitivity to blue light cannot recognize the test area 111 even if the absolute value of the difference [%] of the blue component from the surrounding area 112 is 30%, but can recognize the test area 111 within the surrounding area 112 when the absolute value of the difference [%] of the blue component from the surrounding area 112 is 40% or more. Furthermore, if subject 2 has photosensitivity, subject 2 has high sensitivity to blue light and can therefore recognize the test area 111 within the surrounding area 112 even if the absolute value of the difference [%] of the blue component from the surrounding area 112 is less than 30%.

[0040] Furthermore, for a subject 2 with normal color vision, the higher the luminance of the peripheral region 112 and the test region 111, the easier it is for the subject 2 to recognize the color difference between the peripheral region 112 and the test region 111. On the other hand, if the subject 2 has photosensitivity, which is sensitive to blue light, the high luminance of the peripheral region 112 and the test region 111 will cause the subject 2 to feel dazzled by the sensitivity test image 110B. Therefore, for a subject 2 with photosensitivity, if the "luminance [%] of the peripheral region" is lower than 100%, the subject 2 will be able to easily recognize the color difference between the peripheral region 112 and the test region 111 and the shape of the test region 111. Furthermore, even if the subject 2 has photosensitivity, if the luminance [%] of the peripheral region 112 is reduced, the subject 2 may have difficulty recognizing the test region 111 within the peripheral region 112 if the absolute value of the difference [%] of the blue component from the peripheral region 112 is less than 30%. In this case, if the brightness [%] of the peripheral region 112 is reduced, the subject 2 will be able to recognize the inspection region 111 within the peripheral region 112, so the absolute value of the difference [%] of the blue component from the peripheral region 112 must be changed to 30% or more.

[0041] Thus, the conditions for recognizing the difference in color between the peripheral region 112 and the inspection region 111 (in other words, for recognizing the inspection region 111 within the peripheral region 112) and the conditions for recognizing the shape of the inspection region 111 vary depending on the color vision characteristics of the subject 2. Therefore, by using a plurality of sensitivity test images 110B in which the brightness of the sensitivity test images 110B (brightness of the peripheral region 112 and the inspection region 111) and the color difference of the inspection region 111 from the peripheral region 112 are different, it is possible to determine the color vision characteristics of the subject 2 with respect to blue light. Note that Table 1 shows examples of sensitivity test images 110B in which the difference [%] of the blue component of the inspection region 111 from the peripheral region 112 ranges from −60% to +60%, but the sensitivity test images 110B are not limited to these. For example, a sensitivity inspection image 110B may be prepared in which the difference [%] of the blue component of the inspection area 111 from the surrounding area 112 is less than -60%, or a sensitivity inspection image 110B in which the difference [%] of the blue component of the inspection area 111 from the surrounding area 112 is greater than +60%.

[0042] Tables 2 and 3 show the input values ​​(xR ＢＧ , xG ＢＧ , xB ＢＧ ) and the input values ​​(xR, xG, xB) of the inspection area 111.

[0043]

[0044]

[0045] In the sensitivity inspection image 110R shown in Table 2, when the difference [%] of the red component of the inspection area 111 from the surrounding area 112 is a positive value (+10% to +60), the magnitude of the red component is greater than the green and blue components, and therefore the inspection area 111 has a reddish color. The greater the difference [%] of the red component from the surrounding area 112, the stronger the redness, and the more distinct the color difference between the inspection area 111 and the surrounding area 112. On the other hand, when the difference [%] of the red component of the inspection area 111 from the surrounding area 112 is a negative value (-10% to -60), the green and blue components are greater than the red component, and therefore the color of the inspection area 111 is cyan (a color with strong greenish and blueish hues). The smaller the difference [%] of the red component from the surrounding area 112, the more distinct the cyan color, and the more distinct the color difference between the inspection area 111 and the surrounding area 112.

[0046] In the sensitivity inspection image 110G shown in Table 3, when the difference [%] of the green component of the inspection area 111 from the surrounding area 112 is a positive value (+10% to +60%), the magnitude of the green component is greater than the red and blue components, and therefore the inspection area 111 has a greenish color. The greater the difference [%] of the green component from the surrounding area 112, the stronger the greenness, and the more distinct the color difference between the inspection area 111 and the surrounding area 112. On the other hand, when the difference [%] of the green component of the inspection area 111 from the surrounding area 112 is a negative value (-10% to -60%), the red and blue components are greater than the green component, and therefore the color of the inspection area 111 is magenta (a color with strong reddish and blueish hues). The smaller the difference [%] of the green component from the surrounding area 112, the more distinct the magenta color, and the more distinct the color difference between the inspection area 111 and the surrounding area 112.

[0047] As with the sensitivity test image 110B, in the sensitivity test images 110R and 110G, the subject 2 with normal color vision can easily recognize the color difference between the test area 111 and the surrounding area 112, even when the absolute values ​​of the difference [%] of the red component of the test area 111 from the surrounding area 112 and the difference [%] of the green component of the test area 111 from the surrounding area 112 are small (i.e., when the colors of the test area 111 and the surrounding area 112 are similar). On the other hand, in order for the subject 2 with relatively low sensitivity to red and green light to recognize the color difference between the test area 111 and the surrounding area 112, the absolute values ​​of the difference [%] of the red component of the test area 111 from the surrounding area 112 and the difference [%] of the green component of the test area 111 from the surrounding area 112 must be large. A subject 2 with normal color vision can recognize the inspection area 111 arranged within the surrounding area 112, for example, when the absolute value of the difference [%] of the red component of the inspection area 111 from the surrounding area 112 or the difference [%] of the green component of the inspection area 111 from the surrounding area 112 is 30% or more (i.e., −30% or less or +30% or more). On the other hand, a subject 2 with low sensitivity to red or green light cannot recognize the inspection area 111 even if the absolute value of the difference [%] of the red component of the inspection area 111 from the surrounding area 112 or the difference [%] of the green component of the inspection area 111 from the surrounding area 112 is 30%, but can recognize the inspection area 111 when the absolute value of the difference [%] of the red component of the inspection area 111 from the surrounding area 112 or the difference [%] of the green component of the inspection area 111 from the surrounding area 112 is 50% or more.

[0048] Furthermore, for a subject 2 with normal color vision, the higher the luminance of the peripheral region 112 and the test region 111, the easier it is for the subject 2 to recognize the color difference between the peripheral region 112 and the test region 111 and the shape of the test region 111. On the other hand, if the subject 2 has photosensitivity, which is highly sensitive to blue light, the subject 2 will feel dazzled by the sensitivity test image 110B if the luminance of the peripheral region 112 and the test region 111 is high, making it difficult to recognize the test region 111. Therefore, for a subject 2 with photosensitivity, when the "luminance [%] of the peripheral region" is lower than 100%, the subject 2 will be able to easily recognize the color difference between the peripheral region 112 and the test region 111 and the shape of the test region 111.

[0049] Thus, the conditions for recognizing the difference in color between the peripheral region 112 and the inspection region 111 (in other words, the conditions for recognizing the inspection region 111 within the peripheral region 112) and the conditions for recognizing the shape of the inspection region 111 vary depending on the color vision characteristics of the subject 2. Therefore, by using a plurality of sensitivity inspection images 110R, 110G in which the brightness of the sensitivity inspection images 110R, 110G (the brightness of the peripheral region 112 and the inspection region 111) and the color difference of the inspection region 111 from the peripheral region 112 are different, it is possible to determine the color vision characteristics of the subject 2 with respect to red and green light. Note that Table 2 shows examples of sensitivity inspection images 110R in which the difference [%] of the red component of the inspection region 111 from the peripheral region 112 ranges from −60% to +60%, but the sensitivity inspection images 110R are not limited to these. For example, a sensitivity inspection image 110R in which the difference [%] of the red component of the inspection area 111 from the surrounding area 112 is less than −60% or a sensitivity inspection image 110R in which the difference [%] of the red component of the inspection area 111 from the surrounding area 112 is greater than +60% may be prepared. Also, Table 3 shows examples of sensitivity inspection images 110G in which the difference [%] of the green component of the inspection area 111 from the surrounding area 112 ranges from −60% to +60%, but the sensitivity inspection image 110G is not limited to these. For example, a sensitivity inspection image 110G in which the difference [%] of the green component of the inspection area 111 from the surrounding area 112 is less than −60% or a sensitivity inspection image 110G in which the difference [%] of the green component of the inspection area 111 from the surrounding area 112 is greater than +60% may be prepared.

[0050] [Vision Test Image Set] Next, a vision test image set will be described. A vision test image set is a set of a plurality of vision test images 120 displayed on the display device 10. Fig. 5 shows an example of the vision test image 120.

[0051] The vision test image 120 has a visual target 121 and a background region 122 surrounding the visual target 121. The visual target 121 and the background region 122 have different colors. The visual target 121 is used to test the visual acuity of the subject 2. The visual acuity of the subject 2 is tested by checking whether the subject 2 can recognize the presence and shape of the visual target 121. In the example shown in FIG. 5 , the visual target 121 is a Landolt ring that is commonly used in vision tests.

[0052] The visual acuity test image set includes a plurality of visual acuity test images 120 with different sizes of Landolt rings and different breaks in the Landolt rings. In the example shown in Fig. 5, one optotype 121 is arranged in one visual acuity test image 120, but the present invention is not limited to this configuration. A plurality of optotypes 121 may be arranged in one visual acuity test image 120.

[0053] [Visual Inspection Method] Next, a description will be given of a visual inspection method using the visual inspection system 1. Fig. 6 shows a flowchart of the visual inspection method using the sensitivity inspection image 110 and the visual acuity inspection image 120.

[0054] [Processing Step S101 in FIG. 6] In S101, an appropriate brightness B is determined, which is the brightness [%] of the peripheral region 112 of the sensitivity test image 110 that is appropriate for the subject 2. CENTER In S101, the sensitivity test image 110B is displayed on the display unit 10, and it is examined whether the subject 2 feels dazzled by the sensitivity test image 110B and whether the subject 2 can recognize the test area 111. At this time, the phoropter 20 does not need to be used.

[0055] In S101, first, a sensitivity inspection image 110B in which the difference [%] of the blue component of the inspection area 111 from the surrounding area 112 is −30% is sequentially displayed on the display device 10 while changing the brightness [%] of the surrounding area 112. The displayed sensitivity inspection images 110B may be displayed in ascending or descending order of the brightness [%] of the surrounding area 112. Alternatively, the sensitivity inspection images 110B may be displayed in descending order of the brightness [%] of the surrounding area 112, and then in descending order of the brightness [%] of the surrounding area 112. Alternatively, the brightness [%] of the surrounding area 112 may be changed randomly. When the brightness [%] of the surrounding area 112 changes, the color component of the inspection area 111 also changes accordingly, while the blue component of the inspection area 111 relative to the blue component of the surrounding area 112 remains at −30%. The time for which one sensitivity test image 110B is displayed is, for example, the time during which the subject 2 can respond with the results of confirmation after confirming whether or not the sensitivity test image 110B is dazzling and whether or not he or she can recognize the test area 111. For example, after one sensitivity test image 110B is displayed for one second or more, the next sensitivity test image 110B having a different brightness [%] of the surrounding area 112 is displayed.

[0056] If the subject 2 has normal visual characteristics for blue light, the subject 2 is likely to be able to recognize the test area 111 within the peripheral area 112, regardless of the brightness [%] of the peripheral area 112. If the subject 2 has photosensitivity, the subject 2 will feel dazzled by the sensitivity test image 110B when the brightness [%] of the peripheral area 112 is high. Therefore, the subject 2 with photosensitivity will have difficulty recognizing the test area 111 in the sensitivity test image 110B where the brightness [%] of the peripheral area 112 is relatively high, but will easily recognize the test area 111 in the sensitivity test image 110B where the brightness [%] of the peripheral area 112 is relatively low. On the other hand, if the subject 2 has low luminosity to blue light, the subject 2 will have difficulty recognizing changes in the blue component of the test area 111, and may not be able to recognize the test area 111 in the sensitivity test image 110B where the difference [%] of the blue component of the test area 111 from the peripheral area 112 is -30%. Therefore, by testing whether the subject 2 can recognize the test area 111 within the peripheral area 112, it is possible to test the subject 2's sensitivity to blue light, or the difference between the subject 2's sensitivity to blue light and that of a healthy person.

[0057] If the subject 2 can recognize the test area 111 of the sensitivity test image 110B in which the difference [%] of the blue component of the test area 111 from the surrounding area 112 is -30%, this means that the subject 2's sensitivity to blue light is at least as high as that of a healthy subject. On the other hand, if the subject 2 cannot recognize the test area 111 of the sensitivity test image 110B in which the difference [%] of the blue component of the test area 111 from the surrounding area 112 is -30%, this means that the subject 2's sensitivity to blue light is lower than that of a healthy subject. Furthermore, since the subject 2 who has photosensitivity has a high sensitivity to blue light, even when the brightness [%] of the peripheral area 112 is lower than 100% and the difference [%] of the blue component of the inspection area 111 from the peripheral area 112 is greater than -30% (i.e., the color of the inspection area 111 is closer to the color of the peripheral area 112), there is a possibility that the subject 2 will be able to recognize the inspection area 111 of the sensitivity inspection image 110B.

[0058] The subject 2 identifies the luminance [%] of the peripheral region 112 at which the test area 111 can be recognized while viewing the sensitivity test image 110B in which the luminance [%] of the peripheral region 112 changes. Then, the median (or a value close to the median) of the range of luminance [%] of the peripheral region 112 at which the subject 2 can recognize the test area 111 is designated as the appropriate luminance B CENTER The appropriate brightness B CENTER may be the maximum brightness value within the range of brightness [%] of the peripheral region 112 where the subject 2 can recognize the inspection region 111. If the subject 2 can recognize the inspection region 111 regardless of the brightness [%] of the peripheral region 112, 100% is set as the appropriate brightness B CENTER Note that the fact that the subject 2 is not dazzled by the sensitivity test image 110B and can recognize the test area 111 is an example of the first test condition.

[0059] If the subject 2 cannot recognize the inspection area 111 of the sensitivity inspection image 110B in which the difference [%] of the blue component of the inspection area 111 from the surrounding area 112 is -30%, a sensitivity inspection image 110B in which the difference [%] of the blue component of the inspection area 111 from the surrounding area 112 is -40% is displayed. Then, a test is performed to see if the subject 2 can recognize the inspection area 111 within the surrounding area 112 of the displayed sensitivity inspection image 110B. At this time, the brightness [%] of the surrounding area 112 of the displayed sensitivity inspection image 110B may be sequentially changed. If the subject 2 cannot recognize the inspection area 111 of the sensitivity inspection image 110B in which the difference [%] of the blue component of the inspection area 111 from the surrounding area 112 is -40%, the sensitivity inspection image 110B is displayed with the difference [%] of the blue component of the inspection area 111 from the surrounding area 112 set even lower. In this way, the difference [%] of the blue component of the test area 111 from the surrounding area 112 is changed until the test subject 2 can recognize the test area 111. This makes it possible to test the extent to which the test subject 2's sensitivity to blue light is lower than that of a healthy subject. If the test subject 2 can recognize the test area 111 in the sensitivity test image 110B in which the difference [%] of the blue component of the test area 111 from the surrounding area 112 is −30%, a sensitivity test image 110B in which the difference [%] of the blue component of the test area 111 from the surrounding area 112 is closer to 0 (for example, −20% or −10%) may be displayed to test whether the test subject 2 can recognize the test area 111.

[0060] In the process of S101, the sensitivity inspection image 110B in which the difference [%] of the blue component of the inspection area 111 from the surrounding area 112 is −30% is initially displayed, and the difference [%] of the blue component of the inspection area 111 from the surrounding area 112 is changed to a lower value depending on the inspection results. However, embodiments of the present invention are not limited to this process. For example, the sensitivity inspection image 110B in which the difference [%] of the blue component of the inspection area 111 from the surrounding area 112 is +30% may be initially displayed, and the difference [%] of the blue component of the inspection area 111 from the surrounding area 112 in the displayed sensitivity inspection image 110B may be changed to a higher value depending on the inspection results. Alternatively, the sensitivity inspection image 110B may be initially displayed with a small absolute value of the difference [%] of the blue component of the inspection area 111 from the surrounding area 112 (for example, −10% or +10%), and the absolute value of the difference [%] of the blue component of the inspection area 111 from the surrounding area 112 in the displayed sensitivity inspection image 110B may be changed to a larger value depending on the inspection results. Alternatively, the sensitivity inspection image 110B may be initially displayed with a large absolute value of the difference [%] of the blue component of the inspection area 111 from the surrounding area 112 (for example, -60% or +60%), and then, depending on the inspection results, the absolute value of the difference [%] of the blue component of the inspection area 111 of the displayed sensitivity inspection image 110B from the surrounding area 112 may be changed to a smaller value.

[0061] [Processing Step S102 in FIG. 6] In S102, the subject 2 uses a specific red component R that is a red component that allows the subject 2 to recognize the inspection area 111 in the peripheral area 112 of the sensitivity inspection image 110R. VALUE is measured. Specifically, the difference [%] of the red component from the surrounding area 112, at which the subject 2 can recognize the inspection area 111 within the surrounding area 112, is identified. Being able to recognize the inspection area 111 within the surrounding area 112 specifically means being able to recognize the difference in color between the inspection area 111 and the surrounding area 112, and being able to distinguish the inspection area 111 within the surrounding area 112. Note that the phoropter 20 does not need to be used in S102. Furthermore, the subject 2 being able to recognize the inspection area 111 is an example of a second inspection condition.

[0062] In S102, the sensitivity inspection image 110R is displayed on the display device 10 in sequence while changing the difference [%] of the red component of the inspection area 111 from the surrounding area 112 from -10% to -60%. At this time, the brightness [%] of the surrounding area 112 of the sensitivity inspection image 110R is adjusted to the appropriate brightness B specified in S101. CENTER is set to

[0063] In a sensitivity test image 110R in which the difference [%] of the red component of the test area 111 from the surrounding area 112 is -10%, the size of the red component of the test area 111 is 10% smaller than the size of the green component. As the red component of the test area 111 becomes smaller (as the difference [%] of the red component from the surrounding area 112 approaches -60%), the difference between the red component and the green component of the test area 111 increases, and the color difference between the test area 111 and the surrounding area 112 also increases. If the test subject 2 has normal visual characteristics for red and green light, the test subject 2 is likely to be able to recognize the test area 111 within the surrounding area 112 in a sensitivity test image 110R in which the difference [%] of the red component of the test area 111 from the surrounding area 112 is -30% or less. On the other hand, if the subject 2 has a relatively low sensitivity to red light, there is a possibility that the subject 2 will not be able to recognize the test area 111 in the sensitivity test image 110R in which the difference [%] of the red component of the test area 111 from the surrounding area 112 is −30%. Therefore, by testing whether the subject 2 can recognize the test area 111 within the surrounding area 112, it is possible to test the subject 2's sensitivity to red light, or the difference between the subject 2's sensitivity to red light and that of a healthy subject. In other words, it is possible to test the sensitivity of the L cone cells of the subject 2, or the difference between the sensitivity of the L cone cells of the subject 2 and that of a healthy subject.

[0064] If the subject 2 can recognize the test area 111 of the sensitivity test image 110R in which the difference [%] of the red component of the test area 111 from the surrounding area 112 is -30%, this means that the subject 2's sensitivity to red light is at least as high as that of a healthy subject. On the other hand, if the subject 2 cannot recognize the test area 111 of the sensitivity test image 110R in which the light color component of the test area 111 is -30%, this means that the subject 2's sensitivity to red light is lower than that of a healthy subject.

[0065] If the subject 2 cannot recognize the inspection area 111 of the sensitivity inspection image 110R in which the difference [%] of the red component of the inspection area 111 from the surrounding area 112 is -30%, the difference [%] of the red component of the inspection area 111 of the sensitivity inspection image 110R from the surrounding area 112 is changed to -40% and displayed. Then, it is examined whether the subject 2 can recognize the inspection area 111 within the surrounding area 112 of the displayed sensitivity inspection image 110R. At this time, the brightness [%] of the surrounding area 112 of the displayed sensitivity inspection image 110R may be sequentially changed. If the subject 2 cannot recognize the inspection area 111 of the sensitivity inspection image 110R in which the difference [%] of the red component of the inspection area 111 from the surrounding area 112 is -40%, the sensitivity inspection image 110R is displayed with the red component of the inspection area 111 set even lower. In this way, the sensitivity test images 110R are sequentially displayed on the display device 10 while changing the difference [%] of the red component of the test area 111 from the surrounding area 112 from -10% to -60%, and among the differences [%] of the red component from the surrounding area 112 at which the test area 111 can be recognized by the test subject 2, the difference [%] of the red component from the surrounding area 112 with the smallest absolute value is identified. In other words, among the sensitivity test images 110R at which the test area 111 can be recognized by the test subject 2, the one in which the color of the surrounding area 112 is closest to that of the test area 111 is identified. This makes it possible to test the extent to which the test subject 2's sensitivity to red light differs from that of a healthy subject.

[0066] In the process of S102, the sensitivity inspection image 110R in which the difference [%] of the red component of the inspection area 111 from the surrounding area 112 is −10% is initially displayed, and the difference [%] of the red component of the inspection area 111 from the surrounding area 112 is changed to a lower value depending on the inspection results. However, embodiments of the present invention are not limited to this process. For example, the sensitivity inspection image 110R in which the difference [%] of the red component of the inspection area 111 from the surrounding area 112 is +10% may be initially displayed, and the difference [%] of the red component of the inspection area 111 from the surrounding area 112 in the displayed sensitivity inspection image 110R may be changed to a higher value depending on the inspection results. Alternatively, the sensitivity inspection image 110R may be initially displayed with a large absolute value of the red component of the inspection area 111 (for example, −60% or +60%), and the absolute value of the difference [%] of the red component of the inspection area 111 from the surrounding area 112 in the displayed sensitivity inspection image 110R may be changed to a lower value depending on the inspection results.

[0067] [Processing Step S103 in FIG. 6] In S103, the subject 2 selects a specific green component G, which is a green component that allows the subject 2 to recognize the inspection area 111 in the peripheral area 112 of the sensitivity inspection image 110G. VALUE Specifically, in S103, the sensitivity inspection image 110G is displayed on the display device 10 in sequence while changing the difference [%] of the green component of the inspection area 111 from the surrounding area 112 from -10% to -60%. At this time, the brightness [%] of the surrounding area 112 of the sensitivity inspection image 110R is measured by the appropriate brightness B specified in S101. CENTER is set to

[0068] In S103, similar to the test in S102, it is tested whether the subject 2 can recognize the test area 111 within the peripheral area 112 of the sensitivity test image 110G. Specifically, it is tested whether the subject 2 can recognize the difference in color between the test area 111 and the peripheral area 112 and whether he or she can distinguish the shape of the test area 111. Note that the phoropter 20 does not have to be used in S103.

[0069] The inspection method in S103 is the same as the inspection in S102, except that the sensitivity inspection image 110G is used instead of the sensitivity inspection image 110R, and the difference [%] of the green component of the inspection area 111 from the surrounding area 112 is changed instead of the difference [%] of the red component of the inspection area 111 from the surrounding area 112. Specifically, the sensitivity inspection images 110G are sequentially displayed on the display device 10 while the difference [%] of the green component of the inspection area 111 from the surrounding area 112 is changed from −10% to −60%, and the difference [%] of the green component from the surrounding area 112 with the smallest absolute value is identified among the differences [%] of the green component that allows the subject 2 to recognize the inspection area 111. This inspection makes it possible to inspect the subject 2's sensitivity to green light, or the difference between the subject 2's sensitivity to green light and that of a healthy subject. In other words, it is possible to examine the sensitivity of the M cone cells of the subject 2, or the difference between the sensitivity of the M cone cells of the subject 2 and the sensitivity of the M cone cells of a healthy subject.

[0070] Through the above processes from S101 to S103, the subject's sensitivity to each of the RGB light components is tested.

[0071] In the example shown in FIG. 6 , both the sensitivity of the subject 2 to red light and the sensitivity of the subject 2 to green light are tested in S102 and S103, but the processing of this embodiment is not limited to this. For example, if it is known in advance that the subject 2 has low sensitivity to either green light or red light, only a test (either S102 or S103) using only the sensitivity test image 110 that changes the color to which the subject 2 has low sensitivity may be performed. For example, if the subject 2 has type 1 color weakness, which means low sensitivity to red, the test in S102 may be performed, and the test in S103 may be omitted. Alternatively, if the subject 2 has type 2 color weakness, which means low sensitivity to green, the test in S103 may be performed, and the test in S102 may be omitted.

[0072] Furthermore, when only the degree of photosensitivity of the subject 2 is to be tested, only the test in S101 may be performed. The degree of photosensitivity is tested by determining the luminance [%] of the peripheral region 112 at which the subject 2 feels dazzled. Therefore, when testing the degree of photosensitivity, it is not necessarily necessary to use the sensitivity test image 110B, and the sensitivity test image 110R or the sensitivity test image 110G may also be used.

[0073] [Processing Step S104 in FIG. 6] In S104, the specific red component R VALUE and specific green component G VALUE The difference between the sensitivity to red light and the sensitivity to green light of the subject 2 is calculated using the following equation. In this embodiment, the ratio between the sensitivity to red light and the sensitivity to green light is calculated.

[0074] Specific red component R VALUE The absolute value of the specific green component G VALUE If the absolute value of |G| is greater than 1, the subject 2's sensitivity to red light is less than that to green light. In this case, the sensitivity ratio is |G| VALUE / R VALUE | (G VALUE / R VALUE On the other hand, the specific red component R VALUE The absolute value of the specific green component G VALUE If the absolute value of |R VALUE / G VALUE |(R VALUE / G VALUE The calculated sensitivity ratio is used to determine the characteristics of a correction filter that corrects the visual characteristics of the subject 2.

[0075] [Processing Step S105 in FIG. 6] In S105, the visual acuity of the subject 2 is measured using the phoropter 20 and the visual acuity test image 120.

[0076] The brightness [%] of the background region 122 of the visual acuity test image 120 is set to the appropriate brightness B 120 specified in S101 so that the subject 2 does not feel dazzled by the visual acuity test image 120. CENTERis set to

[0077] The color of the optotype 121 in the vision test image 120 is set so that the subject 2 can easily recognize the difference in color from the background region 122. The color of the optotype 121 is, for example, black. This increases the color difference between the background region 122 and the optotype 121, making it easier to measure the visual acuity of the subject 2. Furthermore, by making the optotype 121 black, if the subject 2 has photosensitivity, the subject 2 is less likely to feel dazzled by the optotype 121, and visual acuity can be measured accurately.

[0078] The color of the vision test image 120 may also be adjusted based on the ratio of sensitivity to red light to sensitivity to green light calculated in S104.

[0079] For example, if the subject 2 has a lower sensitivity to red light than to green light, the colors of the background region 122 and the visual target 121 in the vision test image 120 may be set to correct the ratio of these sensitivities. Specifically, the green components of the background region 122 and the visual target 121 are expressed as |G VALUE / R VALUE Alternatively, the red components of the background region 122 and the target 121 may be set lower by |R VALUE / G VALUE Alternatively, both the red and green components of the background region 122 and the target 121 may be adjusted so that the sensitivity ratio is corrected.

[0080] On the other hand, if the subject 2 has a higher sensitivity to red light than to green light, the colors of the background region 122 and the visual target 121 of the visual acuity test image 120 may be set to correct the ratio of these sensitivities. Specifically, the red components of the background region 122 and the visual target 121 are expressed as |R VALUE / G VALUE Alternatively, the green components of the background region 122 and the target 121 may be set lower by |G VALUE / R VALUE Alternatively, both the red and green components of the background region 122 and the target 121 may be adjusted so that the sensitivity ratio is corrected.

[0081] The subject 2 views the visual acuity test image 120 through the trial lens 21 attached to the phoropter 20. Then, a test is performed to see if the subject 2 can recognize the existence and shape of the optotype 121. Specifically, the visual acuity of the subject 2 can be tested by changing the type of trial lens 21 (power, direction of astigmatism axis, etc.) and the size of the optotype 121 when the subject 2 can recognize the existence and shape of the optotype 121.

[0082] If the subject 2 has poor eyesight, the subject 2 may not be able to grasp the shape of the optotype 121 in the vision test image 120 even through the trial lens 21. Therefore, in the vision measurement in S105, the size of the optotype 121 is not limited, and the optotype 121 may be set large according to the visual acuity of the subject 2, or the distance between the subject 2 and the display device 10 may be narrowed.

[0083] As described above, in the visual acuity measurement in S105, if the subject 500 has photosensitivity, the luminance is adjusted so that the subject 2 does not perceive the visual acuity test image 120 as too dazzling. Furthermore, if the subject 2 has a difference in sensitivity to red light and a difference in sensitivity to green light that differs from the sensitivity of a normal person, the color of the visual acuity test image 120 is adjusted according to the color vision characteristics of the subject 2. This prevents the subject 2 from having difficulty recognizing the optotype 121 due to his or her photosensitivity or color vision characteristics, which would result in an inaccurate measurement of visual acuity.

[0084] [Correction Filter] When the visual characteristics of the subject 2 are tested by the visual testing method shown in Fig. 6, the test results are used to create a correction filter that corrects the visual characteristics of the subject 2. The correction filter corrects the visual acuity of the subject 2 and also corrects the photosensitivity and color vision characteristics of the subject 2. The material of the correction filter and the principle by which the transmission spectrum is changed are not particularly limited. Furthermore, the correction filter is worn by the subject 2, for example, like glasses. However, the shape of the correction filter is not particularly limited. The correction filter may be in the shape of a contact lens.

[0085] 7 shows an example of a glasses-like correction filter 300. The correction filter 300 includes a lens that corrects the visual acuity of the subject 2, and a filter provided on the surface of the lens that changes the spectrum of light that passes through. The shape of the lens is determined based on the results of the visual acuity measurement in S105, and is configured to correct the visual acuity of the subject 2. The filter includes, for example, a filter 300B for light in the blue region, a filter 300G for light in the green region, and a filter 300R for light in the red region. Each of the filters 300B, 300G, and 300R has a band B that changes the light transmittance. B , B G , B R It has the following characteristics.

[0086] Filter 300B changes the transmittance of light in the blue region (in other words, it absorbs or reflects a portion of the blue light) but transmits green and red light unchanged (in other words, it has low absorptance and reflectance for green and red light). Filter 300G changes the transmittance of light in the green region (in other words, it absorbs or reflects a portion of the green light) but transmits blue and red light unchanged (in other words, it has low absorptance and reflectance for blue and red light). Filter 300R changes the transmittance of light in the red region (in other words, it absorbs or reflects a portion of the red light) but transmits green and blue light unchanged (in other words, it has low absorptance and reflectance for green and blue light). Therefore, by combining the three filters 300B, 300G, and 300R, it is possible to individually adjust the transmittance for light in the three RGB wavelength bands.

[0087] 8A to 8C show bands B and B in which the light transmittance of the three filters 300B, 300G, and 300R can be changed. B , B G , B R The horizontal axis of Figures 8(a) to (c) indicates the wavelength of light, and the vertical axis indicates the normalized transmittance of each filter. In Figures 8(a) to (c), the absorption spectra of each cone cell and rod cell are shown superimposed, and the vertical axis of Figures 8(a) to (c) indicates the normalized absorption rate of each cell. S Peak wavelength P of the sensitivity of cone cells Sis approximately 420 nm, the peak wavelength of sensitivity of M cone cells P Ｍ is approximately 534 nm, the peak wavelength of sensitivity of L cone cells P Ｌ is approximately 564 nm, the peak wavelength of sensitivity of rod cells P Rod is approximately 498 nm, the wavelength at which photopic vision is at its maximum sensitivity P Pho is approximately 570 nm (see FIG. 3).

[0088] The filter 300B is designed to focus on the peak wavelength P of the sensitivity of the S cone cells, as shown by the solid arrow in FIG. S (approximately 420 nm) or more, and the peak wavelength P of the sensitivity of rod cells Rod In other words, the transmittance of light having a wavelength of about 498 nm or less can be changed. Ｂ The lower limit of P S and the upper limit is the wavelength P Rod The band B of the filter 300B is Ｂ The lower limit of P S Not limited to band B Ｂ The lower limit of P S The wavelength band may be set to a shorter wavelength band than the wavelength band of the reference wavelength.

[0089] The filter 300B only needs to be able to change the transmittance of light in the blue wavelength band. Ｂ The upper limit of the peak wavelength P Rod (approximately 498 nm). Ｂ Another example of the upper limit of the band B Ｂ is indicated by a dotted arrow.

[0090] For example, the band B of the filter 300B Ｂ The upper limit of is the wavelength X where the absorption spectrum of rod cells and the absorption spectrum of M cone cells intersect. Rod-M (approximately 515 nm). Rod-M The wavelength is the peak wavelength P Rod and the peak wavelength P M Wavelength X is shorter than (approximately 534 nm). Rod-MIn the band with wavelengths longer than , the sensitivity of rod cells is relatively low and the sensitivity of M cone cells is relatively high. Ｂ The upper limit of wavelength X Rod-M If the setting is longer than this, the transmittance of light absorbed by the M cone cells (light in the green wavelength band) may be changed, which may make it impossible to properly correct the visual characteristics of the subject 2.

[0091] Furthermore, the band B of the filter 300B Ｂ The upper limit of the peak wavelength P of the sensitivity of the rod cells Rod For example, the band width B of the filter 300B may be shorter than about 498 nm. Ｂ The upper limit of is the wavelength X where the absorption spectrum of S cone cells and the absorption spectrum of rod cells intersect. S-Rod (approximately 453 nm). S-Rod The wavelength is the peak wavelength P S and the peak wavelength P Rod Wavelength X is shorter than S-Rod In a band having a wavelength shorter than , the sensitivity of rod cells is relatively low and the sensitivity of S cone cells is relatively high. Ｂ The upper limit of wavelength X S-Rod If the wavelength is set shorter than this, a larger proportion of light will be absorbed by the S cones, and light sensitivity may not be adequately compensated for.

[0092] In addition, in order to appropriately correct the influence of rod cells on photosensitivity, the band B of the filter 300B is Ｂ The peak wavelength of sensitivity of rod cells is P Rod Therefore, the band B of the filter 300B is Ｂ The upper limit of the peak wavelength P of the sensitivity of the rod cells Rod may be shorter than the peak wavelength P Rod For example, the sensitivity peak wavelength P Rod and the wavelength X at which the absorption spectrum of rod cells intersects with the absorption spectrum of M cone cells. Rod-MWhen the difference between the band widths is Δ, the band width B of the filter 300B is Ｂ The upper limit of P Rod By setting the range within ±Δ, the influence of rod cells on photosensitivity can be appropriately corrected.

[0093] As shown by the solid line in FIG. 8(b), the filter 300G has a peak sensitivity wavelength P Rod (approximately 498 nm) or more, and the wavelength X at which the absorption spectrum of the M cone cell intersects with the absorption spectrum of the L cone cell M-L The transmittance of light with a wavelength of less than or equal to this wavelength X (approximately 548 nm) is changed. M-L The wavelength is the peak wavelength P M and the peak wavelength P L (approximately 564 nm). In other words, the bandwidth B of the filter 300G is Ｇ The lower limit of the wavelength P Rod and the upper limit is wavelength X M-L is.

[0094] In order to increase the proportion of light in the wavelength band to which M cone cells are sensitive among the light transmitted through the filter 300G, the band B of the filter 300G is Ｇ The lower limit of is the wavelength X where the absorption spectrum of rod cells and the absorption spectrum of M cone cells intersect. Rod-M In this case, the band width B of the filter 300G may be set to about 515 nm. Ｇ is shown by the dotted line in Fig. 8(b) . As a result, only light in the wavelength band to which M cone cells are relatively more sensitive than rod cells and other cone cells is absorbed or reflected by filter 300G.

[0095] Rod cells are cells that respond to the intensity of light and do not affect the subject's color perception (color vision). Ｇ The lower limit of the sensitivity peak wavelength P Rod Even if you set it to , you can still correct for green light.

[0096] The filter 300R is a filter that changes the transmittance of red light of the subject 2, and has the property of absorbing or reflecting light in the wavelength band to which the L cone cells are sensitive.

[0097] As shown by the solid line in FIG. 8(c), the filter 300R is configured to have a wavelength X at which the absorption spectrum of the M cone cell intersects with the absorption spectrum of the L cone cell. M-L In other words, the band B of the filter 300R is Ｒ The lower limit of wavelength X M-L is.

[0098] Wavelength M-L In the band with wavelengths shorter than , the sensitivity of the L cone cells is low and the sensitivity of the M cone cells is dominant. Ｒ The lower limit of wavelength X M-L If the wavelength is set shorter than 1000 nm, not only red light but also green light may be absorbed or reflected by the L cones.

[0099] In addition, the band B of the filter 300R Ｒ The lower limit of the wavelength X M-L Instead, the wavelength P at which photopic vision is most sensitive Pho (approximately 570 nm) may also be used.

[0100] [Example 1 of Correction Filter] Next, an example of the correction filter will be described. Ｂ The transmittance of the appropriate brightness B CENTER For example, the appropriate brightness B CENTER If the ratio is 70%, the band B Ｂ The transmittance of the lens is set to 70%. This compensates for the photosensitivity of the subject 2.

[0101] Filter 300G band B Ｇ and the band width B of the filter 300R. Ｒ The transmittance of the specific red component R is set based on the test results of S102 and S103. VALUEis determined to be −30%, the sensitivity of the subject 2 to red light is approximately the same as the sensitivity of a healthy person to red light. VALUE is specified as −50%, the sensitivity of the subject 2 to green light is lower than the sensitivity of a normal person to red light. In this case, the band B of the filter 300R Ｒ The transmittance of the filter 300G is the band B Ｇ than the transmittance of |R VALUE / G VALUE This corrects for the difference between the sensitivity of the subject 2 to red light and the sensitivity of the subject 2 to green light.

[0102] 9 shows an example of the characteristics of the correction filter 300 in the above example. The horizontal axis of FIG. 9 shows wavelength [nm], and the vertical axis shows transmittance [%] of the correction filter 300. In this example, the band B of the filter 300B Ｂ The transmittance of the filter 300G is set to 70%. Ｇ The transmittance of the filter 300R is set to 100%, and the transmittance of the filter 300R is set to 100%. Ｒ The transmittance of the filter 300G is the band B Ｇ than the transmittance of |R VALUE / G VALUE | times lower (i.e., 30 / 50 = 60%). The correction filter 300 has characteristics that combine the characteristics of the three filters 300R, 300G, and 300B. By using this correction filter 300, it is possible to suppress the subject 2 from feeling glare, and also to correct the difference in sensitivity between the subject 2 to red light and the subject 2 to green light.

[0103] In the example shown in FIG. Ｂ The transmittance in the region with wavelengths shorter than 10 ... Ｂ Since the transmittance is reduced in the band B Ｂ The transmittance in the region having a wavelength shorter than 1000 Hz may not be 0%. For example,Ｂ In the example shown in FIG. Ｒ So, wavelength X M-L (approximately 548 nm) or greater is set to 60%. However, light with wavelengths longer than approximately 650 nm has low absorption in both cone cells and rod cells and has almost no effect on human color vision. Therefore, the transmittance of the correction filter 300 for light with wavelengths longer than approximately 650 nm may be set to any value.

[0104] [Example 2 of Correction Filter] Bandwidth B of Filter 300G Ｇ and the band width B of the filter 300R. Ｒ The transmittance of the filter 300B is Ｂ For example, the transmittance of the appropriate brightness B CENTER If the ratio is 70%, the band B Ｂ The transmittance of the specific red component R is set to 70%. VALUE is specified as -30%, and the specific green component G VALUE is specified as −50%, the band B of the filter 300R Ｒ The transmittance of the band B Ｂ Transmittance of 70% |R VALUE / G VALUE | times (70% × 60% = 42%). Ｇ The transmittance of the band B Ｂ The transmittance is set to 70%, which is the same as the transmittance of the

[0105] 10 shows an example of the characteristics of the correction filter 300 in the above example. The horizontal axis of FIG. 10 shows wavelength [nm], and the vertical axis shows transmittance [%] of the correction filter 300. In this example, the band B of the filter 300B Ｂ Transmittance of filter 300G and band width B Ｇ The transmittance of the filter 300R is set to 70%, and the band B ＲThe transmittance of the correction filter 300 is set to 42% (70% x 60%). By using this correction filter 300, it is possible to suppress the subject 2 from feeling glare, and also to correct the difference in sensitivity between the subject 2 to red light and the subject 2 to green light.

[0106] [Example 3 of Correction Filter] Next, an example of the correction filter 300 when the subject 2 does not have photosensitivity will be described. When the subject 2 does not have photosensitivity and has low sensitivity to blue light, the band B of the filter 300B is Ｂ Transmittance of filter 300G, band B Ｇ transmittance of the filter 300R, band width B Ｒ The transmittance of is set based on the test results of S101 to S103. For example, in the test of S101, if the subject 2 can recognize the test area 111 within the peripheral area 112 of the sensitivity test image 110B, where the difference [%] of the blue component of the test area 111 from the peripheral area 112 is -40%, the subject 2's sensitivity to blue light is 75% (30 / 40) of that of a healthy subject. Also, for example, in the test of S102, if the subject 2 can recognize the test area 111 within the peripheral area 112 of the sensitivity test image 110R, where the difference [%] of the red component of the test area 111 from the peripheral area 112 is -30%, the subject 2's sensitivity to red light is approximately the same as that of a healthy subject. Also, for example, in the test in S103, if the subject 2 can recognize the test area 111 in the peripheral area 112 of the sensitivity test image 110G where the difference [%] of the green component of the test area 111 from the peripheral area 112 is -50%, the sensitivity of the subject 2 to green light is 60% (30 / 50) of that of a healthy subject. In this way, by testing how much the sensitivity of the subject 2 differs from that of a healthy subject to each color of RGB light, the ratio of the sensitivity of the subject 2 to RGB light can be found. In the above example, the band B of the filter 300B is Ｂ The transmittance of the filter 300G is the band B Ｇ The transmittance of the filter 300R is set to 75% of the band B. Ｒ The transmittance of the filter 300G is the band B ＧThe transmittance is set to 60% of the transmittance of the original.

[0107] 11 shows an example of the characteristics of the compensation filter 300 in the above example. The horizontal axis of FIG. 11 shows wavelength [nm], and the vertical axis shows transmittance [%] of the compensation filter 300. In this example, of the three colors of light, RGB, the subject 2 has the lowest sensitivity to green light, so the band B of the filter 300G is Ｇ The transmittance of the band B of the filter 300B is set to 100%. Ｂ The transmittance of the filter 300G is the band B Ｇ The transmittance of the filter 300R is set to 75% of the band B Ｒ The transmittance of the filter 300G is the band B Ｇ The correction filter 300 has a relatively high transmittance for green light, to which the subject 2 has low sensitivity, and a relatively low transmittance for red light, to which the subject 2 has high sensitivity (i.e., similar to that of a healthy person). This makes it possible to correct differences in the subject 2's sensitivity to RGB light.

[0108] 6 is not limited to the above embodiment. For example, the characteristics of the correction filter 300 may be determined using only one or two of the test results S101 to S103 rather than using all of them. Alternatively, the characteristics of the filters 300B, 300G, and 300R may be determined using each of the test results S101 to S103 individually, rather than using the difference or ratio of the sensitivity of the subject 2 to RGB light.

[0109] The correction filter 300 may also be designed to match the visual characteristics of the subject 2. Alternatively, color filters with various characteristics may be prepared in advance, and the correction filter 300 may be produced by combining a plurality of color filters in accordance with the visual characteristics of the subject 2.

[0110] [Effect] According to this embodiment, the sensitivity test image 110 has a peripheral region 112 and a test region 111 provided in the center of the peripheral region 112. By using this sensitivity test image 110, it is possible to test the visual acuity of the subject 2 taking into account the sensitivity to luminance and color vision characteristics.

[0111] For example, according to this embodiment, the brightness of the sensitivity test image 110 is measured so that the subject 2 does not feel dazzled, and the visual acuity of the subject 2 is tested using the visual acuity test image 120 whose brightness has been adjusted based on the measurement result. This prevents the subject 2 from feeling dazzled and being unable to focus on the optotype 121, which makes it impossible to accurately measure the visual acuity.

[0112] Furthermore, according to this embodiment, the color vision characteristics of the subject 2, i.e., the difference between sensitivity to red light and sensitivity to green light, are tested in a state where the luminance of the sensitivity test image 110 is adjusted so that the subject 2 does not perceive the sensitivity test image 110 as being dazzling. This prevents the subject 2 from being unable to gaze at the test area 111 due to perceiving the sensitivity test image 110 as being dazzling, and thus prevents the color vision characteristics of the subject 2 from being unable to be measured accurately.

[0113] Furthermore, according to this embodiment, the visual acuity of the subject 2 is tested in a state where the difference between the sensitivity of the subject 2 to red light and the sensitivity of the subject 2 to green light is adjusted. This prevents the subject 2 from having difficulty recognizing the color of the optotype 121 in the visual acuity test image 120, and allows for accurate measurement of visual acuity.

[0114] According to this embodiment, the colors of the peripheral region 112 and the test region 111 of the sensitivity test image 110 have the same magnitude of any two of the RGB components. Therefore, when testing the visual characteristics of the subject 2 to light of the remaining component, it is possible to prevent the difference in sensitivity of the subject 2 to light of the other two components from affecting the test.

[0115] According to this embodiment, the sensitivity test image set includes a plurality of sensitivity test images 110 in which the colors of the peripheral regions 112 are the same and the colors of the test regions 111 are different from one another. Therefore, when visual characteristics are tested using the colors of the sensitivity test images 110, it is possible to suppress the color of the peripheral regions 112 from affecting the test results of the visual characteristics.

[0116] According to this embodiment, the sensitivity test image set includes a plurality of sensitivity test images 110 that differ from one another in the color or brightness of the peripheral region 112. Therefore, by changing the color or brightness of the peripheral region 112 of the sensitivity test image 110, the degree of photosensitivity of the subject 2 can be tested.

[0117] In this embodiment, the sensitivity test image 110B is used when testing the sensitivity of the subject 2 to blue light, the sensitivity test image 110G is used when testing the sensitivity of the subject 2 to green light, and the sensitivity test image 110R is used when testing the sensitivity of the subject 2 to red light. Therefore, it is possible to test only a specific color that is to be tested out of the three colors RGB.

[0118] The above is a description of exemplary embodiments of the present invention. The embodiments of the present invention are not limited to those described above, and various modifications are possible within the scope of the technical concept of the present invention. For example, the embodiments of the present invention also include appropriate combinations of embodiments explicitly shown as examples in the specification or obvious embodiments.

[0119] [Variant Example] In the above-described embodiment, test images such as the sensitivity test image 110 and the visual acuity test image 120 are displayed on the display device 10, and in the above-described processing steps S101 to S105, the brightness and color of the test images can be changed by changing the image signal input to the display device 10, but the embodiment of the present invention is not limited to this configuration.

[0120] The brightness and color of the test image may be changed by inserting a filter that changes the spectrum of transmitted light or a filter that changes the intensity of transmitted light between the subject 2 and the test image. In this case, multiple color filters with different transmittances for each wavelength band or gray filters that reduce the intensity of light in the visible light band are prepared. These filters are inserted into and removed from the phoropter 20 together with the ophthalmic lens, for example. By inserting one or more color filters or gray filters into the phoropter 20, the brightness and color of the test image seen by the subject 2 can be changed.

[0121] It is desirable that the color filter or gray filter be placed between the test image and the trial lens 21 that corrects the visual acuity of the subject 2. This is because, if a color filter or gray filter is placed between the subject 2 and the trial lens 21, the distance from the subject-side surface of the trial lens 21 to the corneal vertex of the subject (vertex distance) may change from the design value of the vertex distance of the trial lens 21, which may make it impossible to accurately measure the visual acuity of the subject 2. It is also possible to place a color filter or gray filter between the subject 2 and the trial lens 21, and correct the visual acuity by taking into account the change in the vertex distance.

[0122] Furthermore, in the processes of S101, S102, and S103 of the visual inspection method, the sensitivity test image 110 displayed on the display device 10 is manually switched by the examiner operating the operation unit 40, but the embodiment of the present invention is not limited to this configuration. The displayed sensitivity test image 110 may be manually switched by the examiner or the subject 2, or may be partially or completely switched automatically according to a preset program. Furthermore, the visual acuity test image 120 displayed in the process of S105 may also be manually switched by the examiner or the subject 2, or may be partially or completely switched automatically.

[0123] For example, in the process of S101, sensitivity test images 110B having different luminances of the peripheral region 112 are sequentially switched and displayed, and the luminance of the peripheral region 112 at which the subject 2 can recognize the test region 111 without feeling dazzled by the sensitivity test image 110B is identified. At this time, the sensitivity test images 110 may be switched at regular time intervals. Alternatively, the displayed sensitivity test image 110 may be switched in response to an input into the operation unit 40 of whether the subject 2 feels dazzled by the sensitivity test image 110 or whether the subject 2 can recognize the test region 111.

[0124] [Other Variation 1] In the above-described embodiment, both the sensitivity test image 110 and the visual acuity test image 120 are displayed on the display device 10, but the present invention is not limited to this configuration. Fig. 12 is a schematic diagram of a visual inspection system 1A according to a variation of the present invention. In this visual inspection system 1A, the test of the subject 2's sensitivity to brightness and color (i.e., measurements S101 to S104) and the visual acuity measurement of the subject 2 (i.e., measurement S105) are performed using separate devices.

[0125] The visual inspection system 1A includes a display device 10, a control unit 30, and an operation unit 40. The display device 10, the control unit 30, and the operation unit 40 are the same as those shown in FIG. 1. A sensitivity inspection image 110 is displayed on the display device 10. Using this sensitivity inspection image 110, the processes of S101 to S104 of the visual inspection shown in FIG. 6 are executed, and the appropriate luminance B CENTER The ratio of the subject's sensitivity to red light to that to green light is measured.

[0126] The vision testing system 1A further includes a phoropter 20 and an eye chart 130. The phoropter 20 is the same as that shown in FIG. 1 and can be fitted with a trial lens 21. FIG. 14 is a front view of the eye chart 130 as viewed from the subject 2. The eye chart 130 is commonly used for eye tests and has at least one black eye chart 131 arranged on a white background 132. The eye chart 131 is, for example, a Landolt ring, a letter, or a figure, and multiple eye charts 131 of different sizes and shapes are arranged on the eye chart 130. The eye chart 130 is an example of an eye chart image for a vision test.

[0127] When the subject 2 looks directly at the eye chart 130 from a predetermined distance, the subject 2's visual acuity can be measured by checking whether the subject 2 can recognize the presence and shape of each optotype 131. In addition, when the subject 2 looks at the eye chart 130 through the phoropter 20 fitted with the trial lenses 21, the power and type of lens for correcting the subject 2's visual acuity can be identified.

[0128] The visual inspection system 1A includes an inspection filter 22 that is disposed between the trial lens 21 and the visual acuity chart 130 and is capable of changing the intensity and spectrum of light that passes through it. In this embodiment, the inspection filter 22 can be attached to the phoropter 20. The characteristics of the inspection filter 22 are determined by the appropriate luminance B CENTER and the ratio of the subject's sensitivity to red light to that to green light. For example, if the subject 2 has a higher sensitivity to blue light than a healthy person, a test filter 22 with a low transmittance of blue light is used. Furthermore, if there is a difference between the subject 2's sensitivity to red light and that to green light, a test filter 22 with adjusted transmittance for one or both of red light and green light is used to correct this difference. In other words, the characteristics of the test filter 22 are determined in the same manner as the characteristics for correcting photosensitivity and color vision characteristics among the characteristics of the correction filter 300 described above.

[0129] In this way, the sensitivity of the subject 2 to light intensity and color is tested using the sensitivity test image 110, and by using this test result to correct the sensitivity of the subject 2 to light intensity and color using the test filter 22, it is possible to prevent the subject 2's sensitivity to light intensity and color from affecting the test of vision characteristics using the optometric filter 21, making it impossible to test vision accurately.

[0130] [Other Variation 2] In the vision chart 130 of the vision testing system 1A, the background 132 is white and the optotype 131 is black, but the embodiment of the present invention is not limited to this configuration. For example, the vision chart 130 may be displayed on a display device that displays an image based on an image signal. The vision chart 130 displayed on the display device may be able to change the brightness or color of the background 132 or the optotype 131 by changing the image signal. This configuration eliminates the need to insert or remove the test filter 22 used in the vision testing system 1A into or from the phoropter 20.

[0131] [Other Modification 3] Furthermore, the visual acuity measurement of the subject 2 may be performed using a configuration of the visual inspection system 1A excluding the display device 10, the control unit 30, and the operation unit 40. In other words, the visual inspection system 1A may be configured to include an eye chart 130 and a phoropter 20 to which the trial lens 21 and the test filter 22 can be attached. In this case, because the visual inspection system 1A does not include the display device 10, the subject 2's sensitivity to luminance and color is not measured using the sensitivity test image 110.

[0132] In this configuration, the test filter 22 attenuates the light that passes through so that the subject 2 does not feel dazzled by the eye chart 130. The test filter 22 also changes the spectrum of the light that passes through so that the subject 2 can clearly recognize the difference in color between the background 132 and the eye chart 131. In this state, the subject 2 is tested to see if he or she can recognize the presence and shape of the eye chart 131, thereby measuring the visual acuity of the subject 2. According to this configuration, the brightness and color of the eye chart 130 as seen by the subject 2 are changed by the test filter 22, making it possible to set conditions that make it easy for the subject 2 to take the eye chart 130. This eliminates the need to prepare a sensitivity test image 110, thereby simplifying the configuration of the visual inspection system 1A.

[0133] [Other Modification 4] Furthermore, in the above-described embodiment, the visual characteristics of the subject 2 are measured using the sensitivity test image 110 and the visual acuity test image 120, but the embodiment of the present invention is not limited to this configuration. Fig. 14 is a schematic diagram of a visual inspection system 1B in a modification of the embodiment of the present invention. This visual inspection system 1B includes a display device 10B, a control unit 30, an operation unit 40, and a phoropter 20. The control unit 30, the operation unit 40, and the phoropter 20 are the same as those shown in Fig. 1. An eye chart 130B is displayed on the display device 10B. The eye chart 130B is used to test the visual acuity of the subject 2.

[0134] The eye chart 130B displayed on the display device 10B has a background 132B and at least one optotype 131B, similar to the eye chart 130 shown in Fig. 13. Unlike the visual inspection system 1A shown in Fig. 12, in the visual inspection system 1B, the brightness and color of the background 132B and the optotype 131B can be adjusted by changing the image signal output from the control unit 30.

[0135] In the vision testing system 1B, the luminance of the background 132B and the optotype 131B is changed so that the subject 2 does not feel dazzled by the eye chart 130B. Furthermore, the color of at least one of the background 132B and the optotype 131B is changed so that the subject 2 can clearly recognize the difference in color between the background 132B and the optotype 131B. In this state, the visual acuity of the subject 2 is measured by testing whether the subject 2 can recognize the presence and shape of the optotype 131B. According to this configuration, by changing the luminance and color of the eye chart 130B, conditions that make it easy for the subject 2 to take the visual acuity test can be set. This eliminates the need to prepare a sensitivity test image 110, simplifying the configuration of the vision testing system 1B and the program for testing vision.

[0136] [Other Variation 5] The visual inspection system 1 may also be connected to a server via a network. FIG. 15 is a schematic diagram of a visual inspection system 1C according to a variation of the embodiment of the present invention. The visual inspection system 1C shown in FIG. 15 is identical to the visual inspection system 1 shown in FIG. 1 except that the control unit 30 includes a communication interface 34 and is connected to the server 50 via the communication interface 34. The communication interface 34 may be configured for either wired or wireless communication. For example, the control unit 30 and the server 50 are connected via a network. The server 50 stores a test program for the visual inspection method, sensitivity test images 110, and visual acuity test images 120. The control unit 30 of the visual inspection system 1 can receive the test program and test image data from the server and use them in the visual inspection. The control unit 30 can also store the results of the visual inspection of the subject 2 and transmit them to the server. The server 50 is an example of an external information processing device.

[0137] The server 50 can be connected to multiple vision testing systems 1C via a network and can collect visual test results from each of the vision testing systems 1C. The visual test results collected by the server can be used to improve the visual test. For example, if it is known in advance that the visual characteristics of a subject to be tested are similar to the visual characteristics of subjects who have previously undergone visual tests, the burden of the test can be reduced by omitting some or all of the subject's visual test. In addition, the results of multiple visual tests can be used to update the test program, sensitivity test images 110, and visual acuity test images 120, or to develop new test programs, sensitivity test images 110, and visual acuity test images 120 to perform more accurate visual tests.

[0138] 1 is configured such that the sensitivity test image 110 and the visual acuity test image 120 are displayed on the display device 10, and the subject 2 observes the sensitivity test image 110 and the visual acuity test image 120 via the phoropter 20, but the embodiments of the present invention are not limited to this configuration. For example, the vision test system 1 may include a display device that can be worn by the subject 2. The display device that can be worn by the subject 2 is, for example, a head-mounted display or VR (Virtual Reality) goggles that can be worn with a mobile device such as a smartphone.

[0139] 16 is a schematic diagram of a vision inspection system 1D according to a modified embodiment of the present invention. In this vision inspection system 1D, a subject 2 wears a head-mounted display device 10D as an example of a wearable display device.

[0140] The display device is connected to the server 50D via a wired or wireless connection, and receives the test program to be displayed and data on the sensitivity test image 110 and the visual acuity test image 120 from the server 50D. The subject 2 can take the visual test by looking at the sensitivity test image 110 and the visual acuity test image 120 displayed on the display device 10D. The subject 2 inputs information into the display device, such as whether the subject 2 finds the sensitivity test image 110 too dazzling and whether the subject 2 can recognize the optotype 121 in the visual acuity test image 120. The method of inputting information into the display device 10D by the subject is not particularly limited, and may be via an operation unit connected to the display device, or may be input by detecting voice or the subject's head movement.

[0141] 16, the visual examination of the subject can be easily performed because the examiner does not need to operate the display device. Furthermore, when the subject's smartphone is used as the display device, the visual examination can be easily performed because there are no restrictions on the location where the visual examination can be performed.

[0142] The above is a description of exemplary embodiments of the present invention. The embodiments of the present invention are not limited to those described above, and various modifications are possible within the scope of the technical concept of the present invention. For example, the embodiments of the present invention also include appropriate combinations of embodiments explicitly shown as examples in the specification or obvious embodiments.

[0143] [Technical idea disclosed in this specification] [Item 1] A visual testing method for measuring the visual acuity of a subject using test images, wherein the types of test images include visual acuity test images, the visual acuity test images include an optotype for measuring the visual acuity of the subject and a background area around the optotype, and the optotype has a color different from that of the background area, the visual testing method comprising: a visual acuity test image presenting step for presenting the visual acuity test image to the subject; a visual acuity test image modifying step for modifying at least one of the brightness and color of the visual acuity test image; and a visual acuity measuring step for measuring the visual acuity of the subject by testing whether the subject can recognize the optotype when looking at the visual acuity test image.

[0144] [Item 2] The type of test image includes a sensitivity test image, the sensitivity test image including a test area and a peripheral area around the test area, the test area having a color different from that of the peripheral area, and the visual inspection method further includes a sensitivity test image presenting step of presenting the sensitivity test image to the subject, a sensitivity test image modifying step of changing at least one of the luminance and color of the sensitivity test image, and a condition obtaining step of obtaining at least one of the luminance and color of the sensitivity test image that satisfies predetermined test conditions when the subject views the sensitivity test image, and in the visual acuity test image modifying step, at least one of the luminance and color of the visual acuity test image is modified in a state so as to satisfy the predetermined test conditions, based on at least one of the luminance and color obtained in the condition obtaining step.

[0145] [Item 3] The visual inspection method described in Item 2, wherein in the sensitivity inspection image changing step, the luminance of at least the peripheral area out of the inspection area and the peripheral area is changed, and the predetermined inspection conditions include a first inspection condition that is a condition under which the subject does not feel dazzled by the sensitivity inspection image when viewing the sensitivity inspection image.

[0146] [Item 4] The visual inspection method according to Item 3, wherein, in the condition acquisition step, if there are multiple luminances of the peripheral region that satisfy the first inspection condition, one of the multiple luminances of the peripheral region that satisfy the first inspection condition is acquired.

[0147] [Item 5] The visual inspection method according to Item 3 or Item 4, wherein in the sensitivity test image changing step, a filter that changes the intensity of transmitted light is inserted or removed between the subject and the sensitivity test image, thereby changing the brightness of the sensitivity test image.

[0148] [Item 6] The visual inspection method described in Item 2, wherein in the sensitivity inspection image changing step, the difference in color between the peripheral region and the inspection region is changed, and the predetermined inspection conditions include second inspection conditions that allow the subject to recognize the difference in color between the peripheral region and the inspection region when viewing the sensitivity inspection image.

[0149] [Item 7] The visual inspection method according to Item 6, wherein in the condition acquisition step, if there are multiple differences between the color of the surrounding area and the color of the inspection area that satisfy the second inspection condition, one of the multiple differences between the color of the surrounding area and the color of the inspection area that satisfy the second inspection condition is acquired.

[0150] [Item 8] The visual inspection method according to Item 6 or Item 7, wherein in the sensitivity test image changing step, a filter that changes the spectrum of transmitted light is inserted or removed between the subject and the sensitivity test image, thereby changing the color of the sensitivity test image.

[0151] [Item 9] A visual inspection method according to any one of Items 3 to 5, wherein in the sensitivity inspection image changing step, the color of the sensitivity inspection image is changed while satisfying the first inspection condition, and the predetermined inspection condition includes a second inspection condition that allows the subject to recognize a difference in color between the surrounding area and the inspection area when looking at the sensitivity inspection image.

[0152] [Item 10] The visual acuity testing method according to Item 9, wherein in the visual acuity measuring step, the visual acuity test image whose luminance satisfies the first test condition and whose color satisfies the second test condition is presented to the subject.

[0153] [Item 11] The visual acuity testing method according to any one of Items 2 to 10, wherein in the visual acuity measuring step, a plurality of visual acuity test images that satisfy the predetermined test conditions are presented to the subject sequentially or simultaneously, and when the subject looks at the presented plurality of visual acuity test images, it is measured whether the subject can recognize the presence and shape of the visual target in the visual acuity test images.

[0154] [Item 12] The visual acuity testing method according to Item 11, wherein in the visual acuity measuring step, at least one of the size and shape of the optotype is changed while the predetermined test conditions are satisfied, and whether the subject can visually recognize the presence and shape of the optotype is measured.

[0155] [Item 13] A visual inspection method according to Item 11 or Item 12, wherein in the visual acuity measurement step, a trial lens for correcting the visual acuity of the subject is inserted and removed between the subject and the visual acuity test image, and the visual acuity of the subject is measured based on the characteristics of the trial lens when the subject can recognize the presence and shape of the visual target in the visual acuity test image.

[0156] [Item 14] The visual inspection method according to any one of Items 1 to 13, wherein in the visual acuity test image presenting step, the visual acuity test image is displayed on a display device based on an image signal, and in the visual acuity test image changing step, at least one of brightness and color of the visual acuity test image is changed by changing the image signal.

[0157] [Item 15] The visual inspection method according to any one of Items 1 to 13, wherein in the visual acuity test image changing step, a filter that changes at least one of the intensity and spectrum of transmitted light is inserted or removed between the subject and the visual acuity test image, thereby changing at least one of the brightness and color of the visual acuity test image.

[0158] [Item 16] The visual testing method according to any one of Items 2 to 16, wherein in the condition acquisition step, the test area is positioned so that when the subject looks at approximately the center of the sensitivity test image, light emitted from the visual target is imaged in an area inside the fovea centralis on the subject's retina, and the color of the visual target is different from the color of the peripheral area in at least one of the R component, G component, and B component in RGB space.

[0159] [Item 17] The visual inspection method according to any one of Items 2 to 16, wherein in the condition acquisition step, the inspection area is positioned so that when the subject looks at approximately the center of the sensitivity inspection image, light emitted from the visual target is imaged within a range of 2 degrees from the center of the subject's retina.

[0160] [Item 18] A visual acuity test program for causing a computer to execute a method including: a visual acuity test image presenting step of presenting to a subject a visual acuity test image including a visual target for measuring the visual acuity of the subject and a background area surrounding the visual target, wherein the visual target has a color different from the color of the background area; a visual acuity test image modifying step of modifying at least one of the brightness and color of the visual acuity test image; and a visual acuity measuring step of measuring the visual acuity of the subject by testing whether the subject can recognize the visual target when looking at the visual acuity test image.

[0161] [Item 19] A visual inspection program according to Item 18, further comprising: a sensitivity test image presenting step of presenting to the subject a sensitivity test image including a test area and a peripheral area surrounding the test area, wherein the test area has a color different from that of the peripheral area; a sensitivity test image modifying step of changing at least one of the brightness and color of the sensitivity test image; and a condition obtaining step of obtaining at least one of the brightness and color of the sensitivity test image that satisfies predetermined inspection conditions when the subject views the sensitivity test image, wherein in the visual acuity test image modifying step, at least one of the brightness and color of the visual acuity test image is modified so as to satisfy the predetermined inspection conditions based on at least one of the brightness and color obtained in the condition obtaining step.

[0162] [Item 20] The visual inspection program described in Item 19, wherein in the sensitivity inspection image changing step, the brightness of at least the peripheral area of ​​the inspection area and the peripheral area is changed, and the predetermined inspection conditions include a first inspection condition under which the subject does not feel dazzled by the sensitivity inspection image when viewing the sensitivity inspection image.

[0163] [Item 21] The visual inspection program according to Item 20, wherein in the condition acquisition step, if there are multiple luminances of the peripheral region that satisfy the first inspection condition, one of the multiple luminances of the peripheral region that satisfy the first inspection condition is acquired.

[0164] [Item 22] The visual inspection program described in Item 19, wherein in the sensitivity inspection image changing step, the difference in color between the peripheral area and the inspection area is changed, and the predetermined inspection conditions include second inspection conditions that allow the subject to recognize the difference in color between the peripheral area and the inspection area when viewing the sensitivity inspection image.

[0165] [Item 23] The visual inspection program according to Item 22, wherein in the condition acquisition step, if there are multiple differences between the color of the surrounding area and the color of the inspection area that satisfy the second inspection condition, one of the multiple differences between the color of the surrounding area and the color of the inspection area that satisfy the second inspection condition is acquired.

[0166] [Item 24] A visual inspection program as described in Item 20 or Item 21, wherein in the sensitivity inspection image changing step, the color of the sensitivity inspection image is changed while satisfying the first inspection condition, and the predetermined inspection condition includes a second inspection condition that allows the subject to recognize the color difference between the surrounding area and the inspection area when looking at the sensitivity inspection image.

[0167] [Item 25] The vision testing program according to Item 24, wherein in the visual acuity measuring step, the visual acuity test image whose luminance satisfies the first test condition and whose color satisfies the second test condition is presented to the subject.

[0168] [Item 26] A visual inspection program according to any one of Items 19 to 25, wherein in the visual acuity measurement step, a plurality of visual acuity test images that satisfy the predetermined test conditions are presented to the subject sequentially or simultaneously, and when the subject looks at the presented plurality of visual acuity test images, it is measured whether the subject can recognize the presence and shape of the visual target in the visual acuity test images.

[0169] [Item 27] ​​The visual acuity testing program according to Item 26, wherein in the visual acuity measuring step, at least one of the size and shape of the optotype is changed while the predetermined test conditions are satisfied, and whether the subject can visually recognize the presence and shape of the optotype is measured.

[0170] [Item 28] A visual testing program according to any one of Items 19 to 27, wherein in the condition acquisition step, the test area is positioned so that when the subject looks at approximately the center of the sensitivity test image, light emitted from the visual target is imaged in an area inside the fovea centralis on the subject's retina, and the color of the visual target differs from the color of the peripheral area in at least one of the R component, G component, and B component in RGB space.

[0171] [Item 29] A visual testing program according to any one of Items 19 to 27, wherein in the condition acquisition step, the test area is positioned so that when the subject looks at approximately the center of the sensitivity test image, light emitted from the visual target is imaged within a range of 2 degrees from the center of the subject's retina.

[0172] [Item 30] A visual testing system that measures the visual acuity of a subject using test images, wherein types of the test images include visual acuity test images, the visual acuity test images including an optotype for measuring the visual acuity of the subject and a background area around the optotype, the optotype having a color different from that of the background area, the visual testing system comprising: a visual acuity test image presenting unit that presents the visual acuity test image to the subject; a visual acuity test image modifying unit that modifies at least one of the brightness and color of the visual acuity test image; and a visual acuity measuring unit that measures the visual acuity of the subject by testing whether the subject can recognize the optotype when looking at the visual acuity test image.

[0173] [Item 31] The type of test image includes a sensitivity test image, the sensitivity test image including a test area and a peripheral area around the test area, the test area having a color different from that of the peripheral area, and the visual inspection system further includes a sensitivity test image presenting unit that presents the sensitivity test image to the subject, a sensitivity test image modifying unit that changes at least one of the brightness and color of the sensitivity test image, and a condition acquiring unit that acquires at least one of the brightness and color of the sensitivity test image that satisfies predetermined test conditions when the subject views the sensitivity test image, and the visual acuity test image modifying unit changes at least one of the brightness and color of the visual acuity test image based on at least one of the brightness and color acquired by the condition acquiring unit, so as to satisfy the predetermined test conditions.

[0174] [Item 32] The visual inspection system described in Item 31, wherein the sensitivity inspection image modification unit changes the brightness of at least the peripheral area out of the inspection area and the peripheral area, and the predetermined inspection conditions include a first inspection condition under which the subject does not feel dazzled by the sensitivity inspection image when viewing the sensitivity inspection image.

[0175] [Item 33] The visual inspection system according to Item 32, wherein, when there are multiple luminances of the surrounding area that satisfy the first inspection condition, the condition acquisition unit acquires one of the multiple luminances of the surrounding area that satisfy the first inspection condition.

[0176] [Item 34] The visual inspection system described in Item 32 or Item 33, further comprising a filter that can be inserted or removed between the subject and the sensitivity test image to change the intensity of the transmitted light, and the sensitivity test image changing unit changes the brightness of the sensitivity test image by inserting or removing the filter between the subject and the sensitivity test image.

[0177] [Item 35] The visual inspection system described in Item 31, wherein the sensitivity inspection image modification unit modifies the difference in color between the surrounding area and the inspection area, and the predetermined inspection conditions include second inspection conditions that allow the subject to recognize the difference in color between the surrounding area and the inspection area when viewing the sensitivity inspection image.

[0178] [Item 36] The visual inspection system according to Item 35, wherein, when there are multiple differences between the color of the surrounding area and the color of the inspection area that satisfy the second inspection condition, the condition acquisition unit acquires one of the multiple differences between the color of the surrounding area and the color of the inspection area that satisfy the second inspection condition.

[0179] [Item 37] The visual inspection system described in Item 35 or Item 36, further comprising a filter that can be inserted or removed between the subject and the sensitivity test image to change the spectrum of the transmitted light, and the sensitivity test image changing unit changes the color of the sensitivity test image by inserting or removing the filter between the subject and the sensitivity test image.

[0180] [Item 38] A visual inspection system described in any one of Items 32 to 34, wherein the sensitivity inspection image modification unit changes the color of the sensitivity inspection image while satisfying the first inspection condition, and the predetermined inspection condition includes a second inspection condition that allows the subject to recognize the color difference between the surrounding area and the inspection area when looking at the sensitivity inspection image.

[0181] [Item 39] The visual acuity testing system according to Item 38, wherein the visual acuity testing unit presents to the subject the visual acuity test image whose luminance satisfies the first test condition and whose color satisfies the second test condition.

[0182] [Item 40] A visual inspection system described in any one of Items 31 to 39, wherein the visual acuity test image changing unit sequentially or simultaneously presents to the subject a plurality of visual acuity test images that satisfy the specified test conditions, and the visual acuity measuring unit measures whether the subject can recognize the presence and shape of the visual target in the visual acuity test images when the subject looks at the presented plurality of visual acuity test images.

[0183] [Item 41] The visual acuity test system described in Item 40, wherein the visual acuity test image changing unit changes at least one of the size and shape of the optotype while the predetermined test conditions are satisfied, and the visual acuity measuring unit measures whether the subject can see the existence and shape of the optotype.

[0184] [Item 42] A visual inspection system described in any one of Items 31 to 41, wherein the sensitivity test image presenting unit is a display device that displays the inspection image based on an image signal, and the sensitivity test image changing unit causes the sensitivity test image presenting unit to display the sensitivity test image by outputting the image signal, and changes at least one of the brightness and color of the sensitivity test image by changing the image signal to be output.

[0185] [Item 43] A visual inspection system according to any one of items 31 to 41, further comprising: a communication interface communicably connected to an external information processing device; and a memory unit that stores information indicating at least one of the brightness and color values ​​of the sensitivity inspection image that satisfies the specified inspection conditions and information indicating the visual acuity of the subject, and the information stored in the memory unit is transmitted to the external information processing device via the communication interface.

[0186] [Item 44] The visual inspection system according to Item 43, wherein information indicating the inspection image is received from the external information processing device via the communication interface.

[0187] [Item 45] The visual inspection system according to any one of Items 31 to 41, wherein the sensitivity inspection image presentation unit is a display device that displays the inspection image based on an image signal, and the visual inspection system is wearable on the head of the subject.

[0188] [Item 46] The visual acuity test system described in any one of Items 30 to 45, wherein the visual acuity test image presentation unit is a display device that displays the visual acuity test image based on an image signal, and the visual acuity test image modification unit causes the visual acuity test image presentation unit to display a visual acuity test image by outputting the image signal, and modifies at least one of the brightness and color of the visual acuity test image by modifying the image signal to be output.

[0189] [Item 47] The visual inspection system described in any one of Items 30 to 45, further comprising a filter that can be inserted or removed between the subject and the visual acuity test image to change the intensity of the light that passes through, and the visual acuity test image modification unit changes at least one of the brightness and color of the visual acuity test image by inserting or removing the filter between the subject and the visual acuity test image.

[0190] 1 Visual inspection system 2 Subject 10 Display device 110 Sensitivity inspection image 120 Visual acuity inspection image

Claims

1. A visual testing method for measuring the visual acuity of a subject using test images, wherein types of test images include visual acuity test images, the visual acuity test images including a visual target for measuring the visual acuity of the subject and a background area around the visual target, the visual target having a color different from that of the background area, the visual testing method comprising: a visual acuity test image presenting step for presenting the visual acuity test image to the subject; a visual acuity test image modifying step for modifying at least one of the brightness and color of the visual acuity test image; and a visual acuity measuring step for measuring the visual acuity of the subject by testing whether the subject can recognize the visual target when looking at the visual acuity test image.

2. The visual inspection method of claim 1, wherein the type of test image includes a sensitivity test image, the sensitivity test image including a test area and a peripheral area around the test area, the test area having a color different from that of the peripheral area, and the visual inspection method further includes a sensitivity test image presenting step of presenting the sensitivity test image to the subject, a sensitivity test image modifying step of changing at least one of the brightness and color of the sensitivity test image, and a condition acquisition step of acquiring at least one of the brightness and color of the sensitivity test image that satisfies predetermined test conditions when the subject views the sensitivity test image, and wherein in the visual acuity test image modifying step, at least one of the brightness and color of the visual acuity test image is modified so as to satisfy the predetermined test conditions based on at least one of the brightness and color acquired in the condition acquisition step.

3. A visual inspection method as described in claim 2, wherein in the sensitivity inspection image changing step, the brightness of at least the peripheral area out of the inspection area and the peripheral area is changed, and the predetermined inspection conditions include a first inspection condition under which the subject does not feel dazzled by the sensitivity inspection image when viewing the sensitivity inspection image.

4. The visual inspection method according to claim 3, wherein in the condition acquisition step, if there are multiple luminances of the surrounding area that satisfy the first inspection condition, one of the multiple luminances of the surrounding area that satisfy the first inspection condition is acquired.

5. A visual inspection method as described in claim 3 or claim 4, wherein in the sensitivity test image changing step, the brightness of the sensitivity test image is changed by inserting or removing a filter that changes the intensity of the light that passes through between the subject and the sensitivity test image.

6. A visual inspection method as described in claim 2, wherein in the sensitivity inspection image modification step, the difference in color between the surrounding area and the inspection area is modified, and the predetermined inspection conditions include a second inspection condition that allows the subject to recognize the difference in color between the surrounding area and the inspection area when viewing the sensitivity inspection image.

7. A visual inspection method as described in claim 6, wherein in the condition acquisition step, if there are multiple differences between the color of the surrounding area and the color of the inspection area that satisfy the second inspection condition, one of the multiple differences between the color of the surrounding area and the color of the inspection area that satisfy the second inspection condition is acquired.

8. A visual inspection method as described in claim 6 or claim 7, wherein in the sensitivity test image changing step, the color of the sensitivity test image is changed by inserting or removing a filter that changes the spectrum of transmitted light between the subject and the sensitivity test image.

9. A visual inspection method as described in claim 3, wherein in the sensitivity inspection image changing step, the color of the sensitivity inspection image is changed while satisfying the first inspection condition, and the predetermined inspection condition includes a second inspection condition that allows the subject to recognize the difference in color between the surrounding area and the inspection area when looking at the sensitivity inspection image.

10. The visual inspection method according to claim 9, wherein in the visual acuity measurement step, the visual acuity test image whose luminance satisfies the first test condition and whose color satisfies the second test condition is presented to the subject.

11. A visual inspection method as described in claim 2, wherein in the visual acuity measurement step, a plurality of visual acuity test images that satisfy the specified test conditions are presented to the subject sequentially or simultaneously, and when the subject looks at the presented plurality of visual acuity test images, it is measured whether the subject can recognize the existence and shape of the visual target in the visual acuity test images.

12. A visual inspection method as described in claim 11, wherein in the visual acuity measurement step, at least one of the size and shape of the optotype is changed while the specified test conditions are met, and it is measured whether the subject can see the existence and shape of the optotype.

13. A visual inspection method as described in claim 11 or claim 12, wherein in the visual acuity measurement step, a trial lens for correcting the visual acuity of the subject is inserted and removed between the subject and the visual acuity test image, and the visual acuity of the subject is measured based on the characteristics of the trial lens when the subject can recognize the presence and shape of the visual target in the visual acuity test image.

14. A visual testing method as described in claim 1, wherein in the visual acuity test image presenting step, the visual acuity test image is displayed on a display device based on an image signal, and in the visual acuity test image changing step, at least one of the brightness and color of the visual acuity test image is changed by changing the image signal.

15. A visual inspection method as described in claim 1, wherein in the vision test image changing step, a filter that changes at least one of the intensity and spectrum of the transmitted light is inserted or removed between the subject and the vision test image, thereby changing at least one of the brightness and color of the vision test image.

16. A visual inspection method as described in claim 2, wherein in the condition acquisition step, the inspection area is positioned so that when the subject looks at approximately the center of the sensitivity inspection image, light emitted from the visual target is imaged in an area inside the fovea centralis on the subject's retina, and the color of the visual target differs from the color of the peripheral area in at least one of the R component, G component, and B component in RGB space.

17. A visual inspection method as described in claim 2, wherein in the condition acquisition step, the inspection area is positioned so that when the subject looks at approximately the center of the sensitivity inspection image, light emitted from the visual target is imaged within a range of 2 degrees from the center of the subject's retina.

18. A visual acuity testing program for causing a computer to execute a method including: a visual acuity test image presenting step of presenting to the subject a visual acuity test image including a visual target for measuring the subject's visual acuity and a background area surrounding the visual target, wherein the visual target has a color different from the color of the background area; a visual acuity test image modifying step of modifying at least one of the brightness and color of the visual acuity test image; and a visual acuity measuring step of measuring the subject's visual acuity by testing whether the subject can recognize the visual target when looking at the visual acuity test image.

19. A visual inspection program as described in claim 18, further comprising: a sensitivity test image presenting step of presenting to the subject a sensitivity test image including a test area and a peripheral area surrounding the test area, the test area having a color different from that of the peripheral area; a sensitivity test image modifying step of modifying at least one of the brightness and color of the sensitivity test image; and a condition obtaining step of obtaining at least one of the brightness and color of the sensitivity test image that satisfies predetermined test conditions when the subject views the sensitivity test image, wherein in the visual acuity test image modifying step, at least one of the brightness and color of the visual acuity test image is modified so as to satisfy the predetermined test conditions based on at least one of the brightness and color obtained in the condition obtaining step.

20. A visual inspection program as described in claim 19, wherein in the sensitivity inspection image changing step, the brightness of at least the peripheral area out of the inspection area and the peripheral area is changed, and the predetermined inspection conditions include a first inspection condition under which the subject does not feel dazzled by the sensitivity inspection image when looking at the sensitivity inspection image.

21. A visual inspection program as described in claim 20, wherein in the condition acquisition step, if there are multiple luminances of the peripheral area that satisfy the first inspection condition, one of the multiple luminances of the peripheral area that satisfy the first inspection condition is acquired.

22. A visual inspection program as described in claim 19, wherein in the sensitivity inspection image modification step, the difference in color between the surrounding area and the inspection area is modified, and the predetermined inspection conditions include a second inspection condition that allows the subject to recognize the difference in color between the surrounding area and the inspection area when viewing the sensitivity inspection image.

23. A visual inspection program as described in claim 22, wherein in the condition acquisition step, if there are multiple differences between the color of the surrounding area and the color of the inspection area that satisfy the second inspection condition, one of the multiple differences between the color of the surrounding area and the color of the inspection area that satisfy the second inspection condition is acquired.

24. A visual inspection program as described in claim 20, wherein in the sensitivity inspection image changing step, the color of the sensitivity inspection image is changed while satisfying the first inspection condition, and the predetermined inspection condition includes a second inspection condition that allows the subject to recognize the difference in color between the surrounding area and the inspection area when looking at the sensitivity inspection image.

25. The visual acuity testing program according to claim 24, wherein in the visual acuity measuring step, the visual acuity test image whose luminance satisfies the first test condition and whose color satisfies the second test condition is presented to the subject.

26. A visual acuity testing program as described in claim 19, wherein in the visual acuity testing step, a plurality of visual acuity test images that satisfy the specified test conditions are presented to the subject sequentially or simultaneously, and when the subject looks at the presented plurality of visual acuity test images, it is measured whether the subject can recognize the presence and shape of the visual target in the visual acuity test images.

27. A visual acuity testing program as described in claim 26, wherein in the visual acuity measuring step, at least one of the size and shape of the optotype is changed while the specified test conditions are met, and it is measured whether the subject can see the presence and shape of the optotype.

28. A visual testing program as described in claim 19, wherein in the condition acquisition step, the test area is positioned so that when the subject looks at approximately the center of the sensitivity test image, light emitted from the visual target is imaged in an area inside the fovea centralis on the subject's retina, and the color of the visual target differs from the color of the peripheral area in at least one of the R component, G component, and B component in RGB space.

29. A visual testing program as described in claim 19, wherein in the condition acquisition step, the test area is positioned so that when the subject looks at approximately the center of the sensitivity test image, light emitted from the visual target is imaged within a range of 2 degrees from the center of the subject's retina.

30. A visual testing system that measures the visual acuity of a subject using test images, wherein types of the test images include visual acuity test images, the visual acuity test images including an optotype for measuring the visual acuity of the subject and a background area around the optotype, the optotype having a color different from that of the background area, the visual testing system comprising: a visual acuity test image presenting unit that presents the visual acuity test image to the subject; a visual acuity test image modifying unit that modifies at least one of the brightness and color of the visual acuity test image; and a visual acuity measuring unit that measures the visual acuity of the subject by testing whether the subject can recognize the optotype when looking at the visual acuity test image.

31. The visual inspection system described in claim 30, wherein the type of test image includes a sensitivity test image, the sensitivity test image including a test area and a peripheral area around the test area, the test area having a color different from that of the peripheral area, and the visual inspection system further includes: a sensitivity test image presenting unit that presents the sensitivity test image to the subject; a sensitivity test image modifying unit that changes at least one of the brightness and color of the sensitivity test image; and a condition acquiring unit that acquires at least one of the brightness and color of the sensitivity test image that satisfies predetermined test conditions when the subject views the sensitivity test image, and the visual acuity test image modifying unit changes at least one of the brightness and color of the visual acuity test image based on at least one of the brightness and color acquired by the condition acquiring unit, so as to satisfy the predetermined test conditions.

32. A visual inspection system as described in claim 31, wherein the sensitivity inspection image modification unit modifies the brightness of at least the peripheral area out of the inspection area and the peripheral area, and the predetermined inspection conditions include a first inspection condition under which the subject does not feel dazzled by the sensitivity inspection image when viewing the sensitivity inspection image.

33. The visual inspection system according to claim 32, wherein, when there are multiple luminances of the surrounding area that satisfy the first inspection condition, the condition acquisition unit acquires one of the multiple luminances of the surrounding area that satisfy the first inspection condition.

34. A visual inspection system as described in claim 32 or claim 33, further comprising a filter that can be inserted or removed between the subject and the sensitivity test image to change the intensity of the light that passes through, and the sensitivity test image changing unit changes the brightness of the sensitivity test image by inserting or removing the filter between the subject and the sensitivity test image.

35. A visual inspection system as described in claim 31, wherein the sensitivity inspection image modification unit modifies the difference in color between the surrounding area and the inspection area, and the predetermined inspection conditions include a second inspection condition that allows the subject to recognize the difference in color between the surrounding area and the inspection area when viewing the sensitivity inspection image.

36. A visual inspection system as described in claim 35, wherein, when there are multiple differences between the color of the surrounding area and the color of the inspection area that satisfy the second inspection condition, the condition acquisition unit acquires one of the multiple differences between the color of the surrounding area and the color of the inspection area that satisfy the second inspection condition.

37. A visual inspection system as described in claim 35 or claim 36, further comprising a filter that can be inserted or removed between the subject and the sensitivity test image to change the spectrum of the transmitted light, and the sensitivity test image changing unit changes the color of the sensitivity test image by inserting or removing the filter between the subject and the sensitivity test image.

38. A visual inspection system as described in claim 32, wherein the sensitivity inspection image modification unit modifies the color of the sensitivity inspection image while satisfying the first inspection condition, and the predetermined inspection condition includes a second inspection condition that allows the subject to recognize the difference in color between the surrounding area and the inspection area when looking at the sensitivity inspection image.

39. The visual acuity testing system according to claim 38, wherein the visual acuity testing unit presents to the subject the visual acuity test image whose luminance satisfies the first test condition and whose color satisfies the second test condition.

40. The visual inspection system described in claim 31, wherein the visual acuity test image modification unit sequentially or simultaneously presents a plurality of visual acuity test images that satisfy the specified test conditions to the subject, and the visual acuity measurement unit measures whether the subject can recognize the presence and shape of the visual target in the visual acuity test image when viewing the plurality of visual acuity test images presented to the subject.

41. The visual acuity test system of claim 40, wherein the visual acuity test image modification unit modifies at least one of the size and shape of the target while the specified test conditions are met, and the visual acuity measurement unit measures whether the subject can see the presence and shape of the target.

42. A visual inspection system as described in claim 31, wherein the sensitivity test image presenting unit is a display device that displays the inspection image based on an image signal, and the sensitivity test image changing unit causes the sensitivity test image presenting unit to display the sensitivity test image by outputting the image signal, and changes at least one of the brightness and color of the sensitivity test image by changing the image signal to be output.

43. A visual inspection system as described in claim 31, further comprising: a communication interface communicably connected to an external information processing device; and a memory unit that stores information indicating at least one of the brightness and color values ​​of the sensitivity inspection image that satisfies the specified inspection conditions and information indicating the subject's visual acuity, and the information stored in the memory unit is transmitted to the external information processing device via the communication interface.

44. The visual inspection system according to claim 43, wherein information representing the inspection image is received from the external information processing device via the communication interface.

45. The visual inspection system according to claim 31, wherein the sensitivity inspection image presentation unit is a display device that displays the inspection image based on an image signal, and the visual inspection system is mountable on the head of the subject.

46. ​​The visual acuity test system of claim 30, wherein the visual acuity test image presentation unit is a display device that displays the visual acuity test image based on an image signal, and the visual acuity test image modification unit causes the visual acuity test image presentation unit to display a previous visual acuity test image by outputting the image signal, and modifies at least one of the brightness and color of the visual acuity test image by modifying the image signal to be output.

47. A visual inspection system as described in claim 30, further comprising a filter that can be inserted or removed between the subject and the visual acuity test image to change the intensity of the light that passes through, and the visual acuity test image modification unit changes at least one of the brightness and color of the visual acuity test image by inserting or removing the filter between the subject and the visual acuity test image.

Images