Visual examination tools

Abstract

To provide a visual testing tool that enables accurate testing in visual examinations for infants and children, such as the visual examination during the 3-year-old health checkup. [Solution] A visual examination device 1 for use in visual examinations, comprising at least two surfaces, wherein one surface 10 has a target 11 for visual acuity testing, and the other surface 20 has a target 21 for binocular vision testing. Preferably, the target for binocular vision testing is made by attaching alternating strip-shaped images for the right eye and left eye to a lenticular lens, and more preferably, the target for visual acuity testing and the target for binocular vision testing are made such that the testing distance for visual acuity testing using the target for visual acuity testing is the same as the testing distance for binocular vision testing using the target for binocular vision testing, in which case the testing distance is preferably 30 cm to 40 cm.

Description

Technical Field

[0001] The present invention relates to a visual inspection tool used in visual inspection.

Background Art

[0002] In the primary examination of the 3-year-old child health check (3-year-old child health examination), vision tests and the like are carried out in each household. The vision test in the primary examination (hereinafter referred to as "primary vision test") usually uses visual targets such as Landolt rings and pictures, and the distance between the 3-year-old child as the subject and the visual target (examination distance) is set to 2.5 m, and it is examined whether the visual acuity of the left and right eyes is 0.5. This primary vision test must be carried out at home with the guardian as the examiner, but there are problems such as the child's concentration not lasting, not being able to properly cover one eye (removing tissues or gauze for covering, etc.), and the child not being able to understand the examination method, so accurate implementation may be difficult in some cases.

[0003] As one of the visual inspections for inspecting visual functions including vision tests, there is binocular vision inspection (binocular vision function inspection). Binocular vision inspection examines the binocular vision function, which is the ability to see an object with both eyes simultaneously, and examines whether the separate information entering from the left and right eyes is fused into one in the brain. Binocular vision inspection is not carried out in the primary examination of the 3-year-old child health check, but by carrying out binocular vision inspection in combination with the vision test, the vision test can be strengthened. For example, when the vision test cannot be accurately carried out, by carrying out binocular vision inspection, it is possible to determine whether the visual acuity of the left and right eyes is normal.

[0004] Since vision tests and binocular vision tests are usually carried out using separate devices and instruments, when both tests are carried out simultaneously, it takes time and cost. In order to solve such problems, technologies for efficiently carrying out both tests have been proposed.

[0005] For example, Japanese Patent Publication No. 2013-208191 (Patent Document 1) proposes a test target for examining visual function using multiple targets having right-eye and left-eye images arranged horizontally apart. In the test target described in Patent Document 1, targets such as Landolt rings are stereoscopically perceptible, and stereoscopic parallax and visual acuity can be measured.

[0006] Japanese Patent Publication No. 11-225961 (Patent Document 2) proposes a visual function measuring device that can measure stereoscopic vision function along with visual acuity by presenting a directional stereoscopic target and having the user respond with its direction. The visual function measuring device described in Patent Document 2 measures stereoscopic vision function by, for example, alternately displaying a target mark consisting of two diagonally shaped roughly E letters that are shifted left and right to the left and right eyes, and by sequentially presenting target marks with different amounts of shift and having the user respond with their direction. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2013-208191 [Patent Document 2] Japanese Patent Application Publication No. 11-225961 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, since the test targets in Patent Document 1 and the visual function measuring device in Patent Document 2 use one or a set of test targets to perform visual acuity tests and binocular vision tests, there is a possibility that the tests may not be accurately performed for infants and children, especially for the visual tests in the first stage of the 3-year-old health checkup (hereinafter referred to as "first stage visual tests"), due to a lack of understanding of the testing method. Furthermore, due to the scale of the tests, it may be difficult for parents to perform them at home.

[0009] This invention was made in light of the circumstances described above, and its purpose is to provide a visual examination tool that enables accurate examinations even in visual examinations targeting infants and children, such as visual examinations during health checkups for three-year-olds. [Means for solving the problem]

[0010] The present invention relates to a visual testing device having at least two surfaces, used in visual examinations, and the above-mentioned objective of the present invention is achieved by having a visual target for visual acuity testing on one surface and a visual target for binocular vision testing on the other surface.

[0011] The above objective of the present invention is more effectively achieved by having a visual acuity test target on the front surface and a binocular vision test target on the back surface, or by having the binocular vision test target made by attaching alternating strip-shaped right-eye and left-eye images to a lenticular lens, or by having the visual acuity test target and the binocular vision test target made such that the testing distance for the visual acuity test using the visual acuity test target and the testing distance for the binocular vision test using the binocular vision test target are the same, or by having the testing distance be between 30 cm and 40 cm. [Effects of the Invention]

[0012] According to the visual examination device of this invention, since it has a side with a target for visual acuity testing and a side with a target for binocular vision testing, visual acuity testing and binocular vision testing can be performed simply by switching between the two sides, so that visual examinations can be accurately performed for infants and children. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows an example of a visual inspection tool according to the present invention, where Figure 1(A) shows the front surface of the visual inspection tool and Figure 1(B) shows the back surface of the visual inspection tool. [Figure 2]These are schematic diagrams illustrating the method for creating visual targets for binocular vision testing. Figure 2(A) is a schematic diagram illustrating the basic shape of the visual target, Figures 2(B) and (C) are schematic diagrams illustrating the shape obtained by shifting the shape shown in Figure 2(A), and Figures 2(D) and (E) are schematic diagrams illustrating the shapes obtained by dividing the shapes shown in Figures 2(B) and (C), respectively, into strips. [Figure 3] This is a schematic diagram illustrating the method for creating visual targets for binocular vision testing, and is a schematic diagram illustrating the figures created from the figures shown in Figures 2(D) and (E). [Figure 4] This is a schematic diagram illustrating the method for creating visual targets for binocular vision testing, specifically a diagram illustrating a visual target composed of a lenticular lens and a geometric shape. [Modes for carrying out the invention]

[0014] In this invention, the visual examination tool has at least two sides, with a visual acuity target for visual acuity testing (hereinafter referred to as "visual acuity target") on one side and a visual target for binocular vision testing (hereinafter referred to as "binocular vision target") on the other side. By having both a visual acuity target and a binocular vision target, it is possible to perform tests using the visual acuity target (visual acuity test) and tests using the binocular vision target (binocular vision test) simultaneously. By using different targets for the visual acuity test and the binocular vision test, the tests can be performed simply, and visual examinations for infants and children, such as the visual examination in the first stage of the 3-year-old health checkup (first visual examination), can be performed accurately.

[0015] In visual acuity tests, Landolt rings are often used as visual acuity targets, and in this invention, Landolt rings can also be used as visual acuity targets. However, other targets such as pictures or hiragana characters may also be used. In addition, in visual acuity tests, visual acuity charts with multiple targets corresponding to visual acuity are often used, and in this consideration, it is also possible to have multiple visual acuity targets on one surface. However, this may result in the visual acuity test tool becoming larger and more difficult to point to, so it is preferable to have one visual acuity target on each surface. In particular, when using the visual acuity test tool of this invention in the first stage of the 3-year-old health checkup (first stage visual acuity test), since this test checks whether the visual acuity of both eyes is 0.5, it is preferable to use a visual acuity target corresponding to a visual acuity of 0.5.

[0016] Binocular vision testing includes tests that use additional tools in addition to the visual target, such as the Titmus stereo test using polarized glasses and the TNO stereo test using red-green glasses. While this invention can accommodate such tests, it is preferable to use it for tests that closely resemble natural vision, using only binocular visual targets without the use of additional tools. For example, the visual testing tool of this invention is preferable for binocular vision tests such as the Lang stereo test using lenticular lenses.

[0017] In this invention, the visual examination tool can be made flat, with a visual acuity target on the front surface and binocular visual targets on the back surface. By making the visual examination tool flat, operability and storage can be improved.

[0018] This invention makes it possible to manufacture visual acuity targets and binocular vision targets so that the distance between the subject and the target (test distance) during visual examination is the same for both visual acuity and binocular vision tests. By making the test distances the same, the examiner or subject of the visual examination can avoid the trouble of changing the test distance for each test, and the inaccuracy of the test distance can be suppressed.

[0019] Furthermore, in the present invention, it is possible to set the inspection distance in visual acuity tests and binocular vision tests between 30 cm and 40 cm. Usually, the inspection distance in visual acuity tests is 5 m, and the inspection distance in the primary visual acuity test is as short as 2.5 m. However, even then, for a caregiver to conduct a visual acuity test 2.5 m away from a child, problems may occur such as the child being unable to concentrate on the test due to uneasiness, or removing tissues, gauze, etc. used to cover one eye, making it impossible to accurately conduct the test. There may also be cases where it is difficult to ensure a 2.5 m inspection distance due to the structure of the room where the visual acuity test is conducted. By shortening the inspection distance to 30 - 40 cm, these problems can be solved.

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each figure, the same reference numerals are assigned to the same components, and the description may be omitted. Also, the structures, shapes, numerical values, etc. in the following description are examples, and the present invention is not limited thereto. Furthermore, in the following, the description is centered on the main structures for implementing the present invention, and the description of general-purpose structures, etc. required for implementing the present invention may be simplified or omitted.

[0021] An example of the vision testing device according to the present invention is shown in FIG. 1. The vision testing device 1 has a flat plate shape with two square sides. FIG. 1(A) shows the front surface of the vision testing device 1, and FIG. 1(B) shows the back surface of the vision testing device 1.

[0022] Visual Acuity Testing Device 1 is designed for use in primary vision tests conducted at home and allows for both visual acuity and binocular vision tests. Primary visual acuity tests are usually conducted at a testing distance of 2.5m, but if the examiner (parent / guardian) is far from the child being tested, it may not be possible to conduct an accurate test. Therefore, the testing distance is set to 40cm, and Visual Acuity Testing Device 1 is designed to accommodate this distance. Shortening the testing distance to 40cm has several advantages, including allowing the test to be conducted while the parent / guardian is close to the child, making it easier for the child to concentrate because the target is close, and allowing the parent / guardian to provide support such as covering one of the child's eyes, thus enabling an accurate test. Visual Acuity Testing Device 1 may also be used for vision tests other than primary vision tests. In addition, the testing distance may be other than 40cm, but for primary vision tests, a testing distance of 30-40cm is preferable for the reasons mentioned above.

[0023] The visual examination device 1 is sized and weighted so that the examiner can hold it in their hand and perform the examination. For example, it has a square shape with sides of 80 mm, and the base to which the visual acuity target 11 and the binocular visual acuity target 21 described later are attached is made of a lightweight material with appropriate strength, such as plastic.

[0024] A visual acuity target 11, which is a visual acuity test target, is attached to the surface 10 of the visual acuity testing device 1. The visual acuity testing device 1 uses a Landolt ring as the visual acuity target 11.

[0025] In the primary visual acuity test, the visual acuity of both eyes is checked to see if they have a visual acuity of 0.5. Therefore, a Landolt ring corresponding to a visual acuity of 0.5 is attached to surface 10 as a visual acuity target 11. Specifically, in a typical visual acuity test at a test distance of 5m, a Landolt ring with a visual acuity of 0.5 has an outer diameter of approximately 14.5mm and a gap width of approximately 2.9mm. The size of the Landolt ring can be calculated as "size ≈ test distance × angle (radians)". Therefore, if the test distance is 40cm, the outer diameter will be approximately 1.16mm and the gap width will be approximately 0.23mm. A Landolt ring of this size is used as the visual acuity target 11.

[0026] A binocular vision target 21, which is a visual target for binocular vision testing, is attached to the back surface 20 of the visual examination device 1. The visual examination device 1 uses a Lang stereo test target that utilizes lenticular lenses as the binocular vision target 21.

[0027] The Lang Stereo Test is a binocular vision test that uses a combination of random dots with a sandstorm pattern and lenticular lenses (lenses with cylindrical lenses arranged in a grid) to create a three-dimensional image. If a three-dimensional image is visible, binocular vision is judged to be normal.

[0028] Here, the method for preparing the binocular target 21 will be explained with reference to Figures 2-4. Figures 2-4 are schematic diagrams illustrating the method for preparing the binocular target 21. In Figure 2, the left and right sides are designated as the "left" and "right" of the figure, respectively, as indicated by the solid arrows, and the same applies to Figure 3. In Figures 2(A), (B), and (C), the center line in the left-right direction is indicated by a dashed line. Note that in Figures 2-4, the scale differs from the actual scale in some cases for the sake of clarity.

[0029] For example, a binocular target 21 is created in which a sector-shaped figure 22 with a central angle of approximately 300°, as shown in Figure 2(A), appears to float and be perceived three-dimensionally. The size of the figure 22 can be set arbitrarily as long as it is recognizable, for example, with a diameter of 2 inches (50.8 mm). Note that the figure that forms the basis of the binocular target 21 is not limited to a sector-shaped figure like figure 22, but can be any figure such as an illustration of an animal or letters, however, for a primary vision test, a figure that a child can understand is preferable.

[0030] In preparing the binocular target 21, first, the figure 22 shown in Figure 2(A) is shifted to the left by a predetermined width (hereinafter referred to as "shift width") as shown in Figure 2(B) to prepare the figure 22a for the right eye, and then the figure 22b for the left eye is prepared by shifting it to the right by the same shift width as shown in Figure 2(C). The shift width is set according to the desired parallax. In other words, the shift width is calculated as "shift width ≈ examination distance × parallax (radians) ÷ 2". For example, when preparing a binocular target 21 with an examination distance of 40 cm and a parallax of 240 arcseconds (approximately 0.00116 radians), the shift width is set to approximately 0.233 mm.

[0031] Next, as shown in Figures 2(D) and (E), shapes 22a and 22b are divided into strips at equal intervals in the left-right direction (hereinafter referred to as "step width"). The step width is set so that two strips fit into one lens that constitutes the lenticular lens 23 (see Figure 4), which will be described later. The setting of the step width will be described later.

[0032] Figure 22c is created by taking strips from figures 22a and 22b that are divided with the same step width, taking every other strip from figures 22a and 22b that are in different positions, and arranging them alternately, as shown in Figure 3. For example, if the strips of figures 22a and 22b are numbered from 1 starting from left to right, figure 22c is created by arranging the odd-numbered strips of figure 22a and the even-numbered strips of figure 22b alternately.

[0033] Then, as shown in Figure 4, the fabricated figure 22c is attached to the lenticular lens 23 to create the binocular target 21. The lenticular lens 23 is a lens in which identical, semi-cylindrical lenses (finely shaped, semi-circular lenses) are arranged regularly in a sheet, and is made of a transparent material such as PET (polyethylene terephthalate), PMMA (polymethyl methacrylate), or polycarbonate. The figure 22c is attached to the side of the lenticular lens 23 opposite to the semi-cylindrical side. At this time, the two strips that make up the figure 22c are attached so that they match on each lens that makes up the lenticular lens 23. In other words, the strip of figure 22a for the right eye and the strip of figure 22b for the left eye are attached as a pair to one lens. Cylindrical lenses have curvature in only one direction and have the characteristic of converging or diffusing light in a straight line. By configuring the binocular target 21 in this way, light from the figure for the right eye of figure 22c enters only the right eye, and light from the figure for the left eye enters only the left eye, so that figure 22 is perceived three-dimensionally.

[0034] Lenticular lenses are standardized by the number of lenses that fit into one inch width, known as LPI (Lines Per Inch). For example, if a 60 LPI lenticular lens is used as lenticular lens 23, there are 60 lenses in one inch width, so the width of one lens is approximately 0.0167 inches (0.423 mm). In this case, the width of the strips in figures 22a and 22b, i.e., the groove width, is approximately 0.00833 inches (0.212 mm). Note that a lenticular lens other than 60 LPI may be used as lenticular lens 23.

[0035] A visual examination method using the visual examination device 1 configured in this way will be described.

[0036] First, a visual acuity test is performed using a visual acuity target 11, which is a Landolt ring corresponding to a visual acuity of 0.5 and is attached to the surface 10 of the visual acuity testing device 1.

[0037] Since the test distance is 40 cm, the visual acuity test tool 1 is placed 40 cm away from the subject. The test distance is measured accurately using a ruler or the like, and the visual acuity test tool 1 is placed so that its surface 10 faces the subject at eye level, is not tilted, and is parallel to the vertical direction. The visual acuity test tool 1 may also be placed by being held by the examiner's hand. Then, the subject or the examiner covers one of the subject's eyes, for example, the left eye, with their palm, and the visual acuity target 11 is presented with the direction of the gap in the Landolt ring fixed in one of the four directions: up, down, left, or right, and the subject is asked to indicate the direction of the gap. In the case of a child subject, as in a primary visual acuity test, instead of having the subject indicate the direction of the gap, a model of the Landolt ring may be given to the subject, and they may be asked to indicate the direction by aligning the orientation of the model with the direction of the gap in the visual acuity target 11.

[0038] The above test is performed on the same eye of the subject, changing the orientation of the gap in the Landolt ring. After performing the test four times in all orientations, if the subject gets three or more correct answers, the visual acuity of that eye is considered to be 0.5 and is judged as "good visual acuity." If the subject gets fewer than three correct answers, the visual acuity of that eye is considered not to be 0.5 and is judged as "poor visual acuity."

[0039] Once the visual acuity test for one eye (e.g., the left eye) is completed, the visual acuity test for the other eye (e.g., the right eye) is performed in the same manner to determine whether the visual acuity is "good" or "poor."

[0040] Next, a binocular vision test is performed using the binocular target 21 attached to the back surface 20 of the visual examination device 1. In cases where the subject is a child, such as in a primary vision test, it is preferable to present the figure 22, which is the basis of the binocular target 21, before performing the binocular vision test, so that the subject can understand that this figure 22 appears three-dimensional.

[0041] The examination distance for the binocular vision test is 40 cm, the same as for the visual acuity test. After the visual acuity test is completed, the visual examination tool 1 is placed upside down in the same position. As with the visual acuity test, the examiner may hold the visual examination tool 1 in their hand. First, the visual examination tool 1 is tilted, and the subject is asked to confirm that they cannot see the figure 22c of the binocular vision target 21. Then, the visual examination tool 1 is positioned parallel to the vertical, and the subject is asked to confirm whether the figure 22c appears to pop out in three dimensions. If the figure 22c appears in three dimensions, the subject's binocular vision function is considered normal, and the result is judged as "good binocular vision." If the figure is not visible, the subject's binocular vision function is considered abnormal, and the result is judged as "poor binocular vision."

[0042] Furthermore, if the visual acuity test results are "poor vision" in both eyes, even if the visual examination device 1 is positioned so that the figure 22c of the binocular target 21 appears to stand out in three dimensions, the figure itself may not be visible. Therefore, it is acceptable to choose not to perform the binocular vision test.

[0043] In the aforementioned visual examinations, even if a visual acuity test cannot be accurately performed, information about the subject's visual acuity can be obtained by conducting a binocular vision test. That is, if the results of the binocular vision test are "good binocular vision" even though the results of the visual acuity test cannot be obtained, it can be inferred that there is no problem with the subject's visual acuity. If the results of the visual acuity test are not obtained and the results of the binocular vision test are "poor binocular vision", it can be inferred that there is a problem with the subject's vision.

[0044] In the above-described embodiment, the visual examination tool 1 is a flat plate with two square faces, but it may have a shape other than a square, or a shape with three or more faces instead of being flat. In the latter case, it is sufficient that at least two faces have visual acuity targets and binocular targets, respectively, and the other faces may have visual acuity targets and / or binocular targets of different sizes and shapes.

[0045] Although the visual examination device 1 is designed for use in primary visual examinations, it may also be designed for use in general visual examinations for adults, etc. In this case, the test distance may be set to a typical 5m, for example, and the visual targets may be prepared with multiple visual acuity targets corresponding to visual acuity values ​​and multiple binocular visual targets corresponding to parallax, and multiple visual examination devices may be created by combining these.

[0046] Furthermore, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention. In addition, matters not explicitly disclosed in the above embodiments, such as the weight of the visual inspection device, do not deviate from what is normally practiced by those skilled in the art, and values ​​that can be easily anticipated by those skilled in the art may be adopted. [Explanation of Symbols]

[0047] 1. Visual examination tools 10 surface 11 Visual optotype 20 Back side 21 Binocular target Figures 22, 22a, 22b, 22c 23 Lenticular lenses

Claims

1. A visual testing device having at least two surfaces, used in visual testing, One side has a visual acuity test target, A visual testing device characterized by having a target for binocular vision testing on the other side.

2. The surface has the aforementioned visual acuity test target, The visual testing device according to claim 1, having a visual target for binocular vision testing on its reverse side.

3. The visual testing device according to claim 1 or 2, wherein the visual target for binocular vision testing is made by attaching strip-shaped images for the right eye and left eye, which are arranged alternately, to a lenticular lens.

4. The visual acuity testing device according to claim 1 or 2, wherein the visual acuity test target and the visual acuity test target are manufactured such that the testing distance for visual acuity testing using the visual acuity test target is the same as the testing distance for binocular vision testing using the visual acuity test target.

5. The visual inspection device according to claim 4, wherein the inspection distance is 30 cm to 40 cm.

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