Optotype presentation device and optotype presentation program

Abstract

To provide a target presentation apparatus and a target presentation program, capable of mitigating a load on a subject at the time of inspection.SOLUTION: A target presentation apparatus for presenting a target to a subject's eye comprises: display control means for making an inspection target be displayed on display means; and target creation means that on the basis of a changeover signal for changing over the inspection target from a first inspection target to a second inspection target differing from the first inspection target, starts creation of the second inspection target. The display control means continues display of the first inspection target for a predetermined time even after acquiring the changeover signal and makes the second inspection target be displayed at any timing after completion of the creation of the second inspection target based on the changeover signal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an optotype presenting device and an optotype presenting program for presenting an optotype to an eye to be examined. [Background technology]

[0002] There is known an optotype presenting device for presenting an optotype to an eye to be examined. For example, in Patent Document 1, test optotypes displayed on a display are switched by an optotype switching signal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-233964 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned optotype presenting device, when switching test optotypes, the display of the test optotype is erased for a certain period of time and the next test optotype is displayed. Recently, it has become possible to employ high-resolution displays in devices. However, high-resolution displays can display test optotypes in greater detail, which can require more time to generate the test optotype. In this case, the time required to erase the current test optotype and switch to the next test optotype is longer, which may cause anxiety and inconvenience to the subject.

[0005] In view of the above-described conventional techniques, the present disclosure has as its technical object to provide an optotype presenting device and an optotype presenting program that can reduce the burden on a subject during an examination. [Means for solving the problem]

[0006] In order to solve the above problems, the present disclosure is characterized by having the following configuration.

[0007] (1) A visual target presenting device according to a first aspect of the present disclosure is a visual target presenting device for presenting a visual target to an eye to be examined, comprising: a display control means for causing a display means to display a test visual target; and a visual target generating means for starting generation of the second test visual target based on a switching signal for switching the test visual target from a first test visual target to a second test visual target different from the first test visual target. The display control means continues displaying the first test visual target for a predetermined time even after acquiring the switching signal, and starts displaying the second test visual target at any timing after completion of generation of the second test visual target based on the switching signal. Further, the display control means continues to display the first test optotype for a generation time required for the optotype generation means to generate the second test optotype, displays a background image after the generation of the second test optotype based on the switching signal is completed, and displays the second test optotype after the background image, while setting the generation time required for the optotype generation means to generate the second test optotype as the predetermined time. It is characterized by: (2) A second aspect of the present disclosure provides an optotype presenting device for presenting an optotype to an eye to be examined, comprising: a display control means for causing a display means to display a test optotype; and an optotype generating means for starting generation of the second test optotype based on a switching signal for switching the test optotype from a first test optotype to a second test optotype different from the first test optotype. The display control means continues displaying the first test optotype for a predetermined time even after acquiring the switching signal, and displays the second test optotype at any time after generation of the second test optotype based on the switching signal is completed. The display control means further displays a background image during generation of the second test optotype based on the switching signal after the predetermined time has elapsed, and displays the second test optotype after the background image. ( 3 ) the first aspect of this disclosure 3 A target presentation program according to an embodiment is a target presentation program used in a target presentation device for presenting a target to an eye to be examined, and when executed by a processor of the target presentation device, causes the target presentation device to execute a display control step of displaying a test target on a display means, and a target generation step of starting generation of the second test target based on a switching signal for switching the test target from a first test target to a second test target different from the first test target, in which the display control step continues displaying the first test target for a predetermined time even after acquiring the switching signal, and displays the second test target at any timing after completion of generation of the second test target based on the switching signal. Furthermore, the display control step continues displaying the first test optotype for a generation time required for generating the second test optotype in the optotype generating step as the predetermined time, displays a background image after generation of the second test optotype based on the switching signal is completed, and displays the second test optotype after the background image. It is characterized by: (4) A fourth aspect of the present disclosure provides an optotype presenting program for use in an optotype presenting device for presenting an optotype to an eye to be examined. The optotype presenting program, when executed by a processor of the optotype presenting device, causes the optotype presenting device to execute a display control step of displaying a test optotype on a display means, and an optotype generation step of starting generation of the second test optotype based on a switching signal for switching the test optotype from a first test optotype to a second test optotype different from the first test optotype. The display control step continues displaying the first test optotype for a predetermined time even after acquiring the switching signal, and displays the second test optotype at any time after generation of the second test optotype based on the switching signal is completed. The display control step further includes displaying a background image during generation of the second test optotype based on the switching signal after the predetermined time has elapsed, and displaying the second test optotype after the background image. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an external view of an optotype presenting device. [Figure 2] FIG. 2 is a schematic diagram of a control system of the optotype presenting device. [Figure 3] 10 is an example of an examination screen. [Figure 4] 10 is a diagram schematically showing the timing of acquiring an optotype switching signal for switching optotypes and switching of optotypes on an LCD. FIG. [Figure 5]FIG. 10 is a diagram schematically illustrating a case where the first test swatch is erased after the generation of the second test swatch is completed. [Figure 6] FIG. 10 is a diagram schematically illustrating a case where no disappearance time is provided in which only the background image is displayed. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Summary> An embodiment of a visual target presenting device according to the present disclosure will be described. The items grouped in < > below can be used independently or in conjunction with each other.

[0010] The optotype presenting device of this embodiment is a device for presenting an optotype to an eye to be examined. The optotype presenting device may be capable of displaying a test optotype to be used in testing the eye to be examined. The optotype presenting device may also be capable of displaying a background image to be used as a background for the test optotype.

[0011] The optotype presenting device may be capable of displaying various types of test optotypes. For example, the test optotypes may be visual acuity test optotypes. Examples include directional optotypes (such as Landolt ring optotypes and tumbling E optotypes) that allow the subject to distinguish directions, character optotypes (such as hiragana optotypes, katakana optotypes, and alphabet optotypes) that allow the subject to read letters, and number optotypes that allow the subject to distinguish numbers. Note that these visual acuity test optotypes may also be single-character optotypes consisting of a single visual acuity test optotype, horizontal line optotypes, vertical line optotypes, and character-crowded optotypes that are composed of multiple visual acuity test optotypes, etc. Furthermore, for example, the test optotypes may be test optotypes different from visual acuity test optotypes. Examples include red-green optotypes, radiation optotypes, binocular vision function test optotypes, etc.

[0012] The optotype presenting device may be capable of displaying various background images. For example, the background image may be a white image. Of course, it may also be an image other than a white image. Furthermore, for example, the background image may be displayed over the entire display area of the display means. Of course, it may also be displayed in a part of the display area (for example, a predetermined number of pixels inward from the edge of the display area).

[0013] <Display control means> The optotype presenting device of this embodiment includes a display control means (e.g., a control unit 20). The display control means displays test optotypes on a display means (e.g., an LCD 3). The display control means also displays a background image on the display means. The display control means may display both the test optotypes and the background image (i.e., superimposing the test optotypes on the background image), or may display only the background optotype. The display control means may also switch between displaying a first test optotype currently displayed on the display means and a second test optotype to be displayed on the display means after the first test optotype.

[0014] The display control means may continue to display the first test optotype for a predetermined time even after receiving the test optotype switching signal. In this case, the first test optotype may be erased from the display means during the generation of the second test optotype. In this case, the first test optotype may be erased from the display means simultaneously (or substantially simultaneously) with the completion of the generation of the second test optotype. In this case, the first test optotype may be erased from the display means after the completion of the generation of the second test optotype.

[0015] The display control means may display the second test index at any timing after the generation of the second test index based on the test index switching signal is completed. In this case, the second test index may be displayed on the display means simultaneously (almost simultaneously) with or immediately after the completion of the generation of the second test index. In addition, in this case, the second test index may be displayed on the display means after a certain time has elapsed since the completion of the generation of the second test index.

[0016] The longer the time between erasing the first test optotype and displaying the second test optotype, the more likely the subject will feel anxiety, confusion, annoyance, etc. during the test. By continuing to display the first test optotype even after receiving a test optotype switching signal and displaying the second test optotype after the generation of the second test optotype is completed, it is possible to reduce such burden on the subject.

[0017] The display control means may continue displaying the first test optotype, with the generation time required for the optotype generation means to generate the second test optotype as the predetermined time. In other words, the display control means may continue displaying the first test optotype until the generation time for the second test optotype has elapsed (i.e., until generation of the second test optotype is completed). This eliminates the time gap between erasing the display of the first test optotype and starting to display the second test optotype, thereby reducing the burden that may be placed on the subject. Note that even if it takes time to generate the second test optotype, controlling the display of the test optotype in this manner can reduce the burden on the subject.

[0018] The display control means may display the background image after completing generation of the second test optotype based on the test optotype switching signal, and then display the second test optotype after the background image. For example, after a predetermined time has elapsed since the display of the first test optotype and generation of the second test optotype has been completed, the display control means may display the background image, and then the second test optotype after that. In other words, the background image may be displayed between the display of the first test optotype and the display of the second test optotype. This allows the subject to easily recognize the switching of the test optotype.

[0019] The display control means may display a background image during generation of the second test optotype based on the test optotype switching signal, after a predetermined time has elapsed since the display of the first test optotype, and may display the second test optotype after the background image. In this case, the background image may be displayed on the display means simultaneously (or substantially simultaneously) with or immediately after the end of the predetermined time for the first test optotype. In this case, the background image may be displayed on the display means a certain time has elapsed since the end of the predetermined time for the first test optotype. In this case, the second test optotype may be displayed on the display means simultaneously (or substantially simultaneously) with or immediately after the completion of generation of the second test optotype. In this case, the second test optotype may be displayed on the display means a certain time has elapsed since the completion of generation of the second test optotype. In other words, the end of display of the background image and the completion of generation of the second test optotype may occur at different times or may coincide (or substantially coincide).

[0020] This reduces the burden on the subject that may be caused by the prolonged generation of the test optotypes, while allowing the subject to easily recognize the change of the test optotypes. Also, by overlapping the display of the background image and the generation of the second test optotype at least partially in time, the test can be carried out efficiently.

[0021] The display control means may end the display of the background image to coincide with the completion of generation of the second test index, and display the second test index after the background image. In this case, the display control means may predict the completion timing of generation of the second test index. For example, the completion timing may be predicted based on test index information including at least one of the type, visual acuity value, etc. of the test index. For example, the completion timing of generation of the second test index may be acquired based on correspondence information (e.g., a correspondence table, an arithmetic expression, etc.) that associates test index information with the generation time required to generate the second test index based on experiments or simulations. Of course, the completion timing may also be predicted and acquired using test index information and information other than the test index information.

[0022] In this case, the display control means may set the timing for erasing the first test optotype (in other words, the timing for starting to display the background image) based on the timing for completing the generation of the second test optotype. For example, the predetermined time for the first test optotype may be the time from the start of displaying the first test optotype until the timing for the erasure is set. When the display of the first test optotype continues for the predetermined time, the first test optotype may be erased and the generation of the second test optotype may be completed, and then the background image and the second test optotype may be displayed in sequence.

[0023] For example, by predicting the timing of completion of generation of the second test optotype and setting the timing of erasing the first test optotype, even if the first test optotype is erased before the generation of the second test optotype is completed, the generation of the second test optotype is completed at the same time as the background image display has been running for a predetermined time. This allows the subject to easily recognize the change of test optotypes using the background image. Furthermore, because the first test optotype can be switched immediately after the generation of the second test optotype is completed, the time spent presenting the test optotypes throughout the entire test can be shortened.

[0024] In this embodiment, the background image displayed between the first and second test optotypes may be displayed for a period long enough to allow the subject to recognize the transition between the first and second test optotypes (i.e., long enough to recognize that the test optotype has disappeared). Because the human eye typically perceives changes continuously over a 1 / 30-second interval, a longer period of time, 0.05 seconds or longer, is preferable. On the other hand, if the background image is displayed for too long, the subject may feel that the transition from the first test optotype to the second test optotype is tedious. Therefore, the background image should be displayed for a period that takes into consideration both the ease of recognition by the subject and the potential inconvenience it may cause to the subject. By appropriately displaying the background image, the test can proceed smoothly and maintain a certain level of test accuracy.

[0025] <Optotype generation means> The optotype presenting device of this embodiment includes optotype generating means (e.g., control unit 20). The optotype generating means starts generating the second test optotype based on a switching signal for switching the test optotype from the first test optotype to the second test optotype. For example, the switching signal may be output by the examiner operating an operating means (e.g., controller 4). As an example, the switching signal may be output by specifying the visual acuity value of the test optotype. Furthermore, for example, the switching signal may be output according to a program that automatically progresses the test on the subject's eye. In this case, the subject may operate an operating means for the subject to output the switching signal. Furthermore, in this case, the switching signal may be output when a predetermined time has elapsed since the test optotype was displayed.

[0026] The optotype generating means may generate the second test optotype based on image processing of a reference image for the test optotype. For example, such image processing may be performed using at least the test optotype information. Furthermore, in addition to the test optotype information, the image processing may be performed using pixel information constituting the display means (e.g., the number of pixels, pixel density, etc.), display information of the test optotype on the display means (e.g., display position, display color, rotation angle, parameters for conversion processing or correction processing for the test optotype, etc.), etc. In this case, the optotype generating means may generate the second test optotype by calculating a magnification for enlarging or reducing the reference image from the test optotype information, pixel information, display information, etc.

[0027] Furthermore, the subjective optometry device may include a corrective optical system that changes the optical characteristics of a visual target light beam from a visual target presenting device and is arranged in the optical path of the light projecting optical system. In this case, the corrective optical system may change the optical characteristics of the visual target light beam by controlling an optical element arranged between the visual target presenting device and an optical member of the light projecting optical system. That is, the corrective optical system may be a phantom lens refractometer (phantom corrective optical system). The corrective optical system may also change the optical characteristics of the visual target light beam by controlling an optical element arranged in front of the subject's eye. That is, the corrective optical system may be an optometry unit (phoropter). For example, the optometry unit may have a lens disk on which multiple optical elements are arranged on the same circumference and a driving means (e.g., a motor) for rotating the lens disk, and the optical elements may be electrically switched by driving the driving means.

[0028] The present disclosure is not limited to the devices described in the present embodiment. For example, terminal control software (programs) that perform the functions of the following embodiments may be supplied to a system or device via a network or various storage media, and a control device (e.g., a CPU) of the system or device may read and execute the program.

[0029] <Example> An example of the optotype presenting device according to this embodiment will be described.

[0030] <Device configuration> FIG. 1 is an external view of an optotype presenting device 1. A liquid crystal display (LCD) 3 for presenting optotypes is disposed on the front (front face) of a housing 2 of the optotype presenting device 1. A receiving unit 5 for receiving operation signals transmitted from a controller 4 is disposed below the front face of the housing 2. The optotypes displayed on the LCD 3 can be switched by operating the controller 4. The controller 4 has a plurality of switches 40 for operating the device body, a liquid crystal display (LCD) 41 for displaying the status of operations performed by each switch, and a transmitting unit 49 for transmitting operation signals based on the operation of each switch. The LCD 41 may be a touch panel that also functions as the switch unit 40. Alternatively, the housing 2 and the controller 4 may be located separately, and various operation signals may be transmitted by remote control.

[0031] In this embodiment, the optotype A displayed on the LCD 3 is composed of a background image a1 and a test optotype a2. For example, the background image a1 is a white image and is displayed across the entire LCD 3. For example, the test optotype a2 is a Landolt ring optotype, and is displayed in the center of the LCD 3 at a size corresponding to the visual acuity value. Note that the test optotype a2 is a single-letter optotype composed of a single Landolt ring optotype, but it may also be a horizontal row optotype, a vertical row optotype, a compact optotype, or the like, composed of multiple Landolt ring optotypes. Furthermore, the test optotype a2 does not necessarily have to be positioned in the center and may be repositioned as appropriate.

[0032] FIG. 2 is a schematic diagram of the control system of the optotype presenting device 1. A control unit 20 is stored inside the housing 2. For example, the control unit 20 includes a CPU (processor), RAM, ROM, etc. The CPU controls the driving of each unit in the optotype presenting device 1. Various types of information are temporarily stored in the RAM. The ROM stores various programs executed by the CPU, a decoder circuit that decodes operation signals from the controller 4, an arithmetic formula for calculating the display size of the test optotype, etc. The control unit 20 may be composed of multiple control units (i.e., multiple processors).

[0033] The control unit 20 is connected to an LCD 3, a receiving unit 5, a non-volatile memory 21 (hereinafter referred to as memory 21), etc. The receiving unit 5 provided in the housing 2 and a transmitting unit 49 provided in the controller 4 are connected via wired or wireless communication. The memory 21 is a non-transitory storage medium that can retain its stored contents even when the power supply is cut off. For example, the memory 21 stores a reference image (vector image) of the test optotype, etc. For example, the memory 21 can be a hard disk drive, a flash ROM, a USB memory, an SD card, etc.

[0034] <Control action> The control operation of the optotype presenting device 1 will be described using an example of a visual acuity test for the subject's eyes.

[0035] The examiner operates the switch unit 40 of the controller 4 to call up an examination screen for specifying the test optotype to be displayed on the LCD 3. In response to an operation signal from the switch unit 40, the control unit 20 causes the LCD 41 to display the examination screen.

[0036] 3 is an example of the test screen 9. The examiner operates the LCD 41 to specify a test optotype (in other words, the type and visual acuity value of the test optotype a2) to be presented to the subject's eye from among the optotype specification buttons 91 that specify the test optotype to be displayed on the LCD 3. For example, the examiner specifies a Landolt ring optotype with a visual acuity value of 1.0 as the test optotype a2.

[0037] The control unit 20 displays the background image a1 and the test optotype a2 on the LCD3 based on an operation signal from the LCD 41. For example, the control unit 20 acquires the display size of the test optotype a2 on the LCD3 by performing a calculation using the specified visual acuity value, the resolution of the LCD3, the size of the reference image of the Landolt ring optotype stored in the memory 21, etc. The control unit 20 also enlarges or reduces the reference image of the Landolt ring optotype according to the display size of the test optotype a2. As a result, the Landolt ring optotype (test optotype a2) corresponding to a visual acuity value of 1.0 is displayed on the LCD3 together with the background image a1. Note that the same Landolt ring optotype and its visual acuity value as specified by the examiner may be displayed on the LCD 41.

[0038] The examiner asks the subject about the orientation of the slits in the Landolt ring displayed on the LCD 3, and changes at least one of the orientation of the slits in the Landolt ring or the visual acuity value depending on the subject's answer.

[0039] For example, the examiner may select the direction switch button 92 to switch only the direction of the slits without switching the visual acuity value of the Landolt ring, regardless of whether the answer is correct or incorrect. In this case, the control unit 20 can switch the direction of the slits by rotating the Landolt ring and displaying it on the LCD 3.

[0040] Furthermore, for example, if the answer is correct, the examiner may select the optotype designation button 91 and change the visual acuity value of the Landolt ring optotype to a visual acuity value one level higher. In other words, the increments of the visual acuity value of the Landolt ring optotype may be increased, and the value may be changed to a value larger than the current value. Furthermore, for example, if the answer is incorrect, the examiner may select the optotype designation button 91 and change the visual acuity value of the Landolt ring optotype to a visual acuity value one level lower. In other words, the increments of the visual acuity value of the Landolt ring optotype may be decreased, and the value may be changed to a value smaller than the current value. At this time, the control unit 20 executes the above-described calculation again because the visual acuity value designated by the examiner has changed, and can change the visual acuity value by displaying the Landolt ring optotype (test optotype a2) corresponding to the designated visual acuity value together with the background image a1 on the LCD 3.

[0041] In the optotype presenting device 1, the control unit 20 receives an operation signal (optotype switching signal) from the LCD 41, thereby generating the next test optotype a2 and displaying it on the LCD 3. The test optotype a2 that the LCD 3 can display is limited depending on the number of pixels constituting the LCD 3. For example, the greater the number of pixels in the LCD 3, the higher the resolution, and the more detailed and smooth the test optotype a2 can be displayed. However, when the test optotype a2 is displayed using a larger number of pixels (i.e., the greater the number of pixels used for the test optotype a2 in the LCD 3), the time required to generate the next test optotype a2 may increase. In particular, complex test optotypes a2, such as a vertical line optotype, a horizontal line optotype, or a crowded optotype, that are composed of multiple Landolt rings, tend to take a long time to generate.

[0042] Therefore, even if the display of the current test optotype a2 is erased based on the optotype switching signal from the LCD 41, if the next test optotype a2 has not yet been generated, only the background image a1 will be displayed on the LCD 3 until the generation of the next test optotype a2 is completed. Note that, although there are individual differences between subjects, if only the background image a1 is displayed for more than a certain period of time, it may cause anxiety or annoyance to the subject. In other words, the longer it takes to generate the next test optotype a2, the more burden it may place on the subject.

[0043] In this embodiment, the burden on the subject can be reduced by controlling the timing of switching between the current test optotype a2 and the next test optotype a2. In the following, the current test optotype a2 will be referred to as the first test optotype a21, and the next test optotype a2 will be referred to as the second test optotype a22, and the details will be explained.

[0044] 4 is a diagram schematically illustrating the timing of acquiring an optotype switching signal for switching optotypes (test optotypes) and switching of the optotypes on the LCD 3. The widths of the background image a1, the first test optotype a21, and the second test optotype a22 represent the length of time they are displayed on the LCD 3. The arrows represent the timing T1 when the control unit 20 acquires the optotype switching signal, the timing T2 when the display of the first test optotype a21 is erased, the timing T3 when generation of the second test optotype a22 is completed, and the timing T4 when display of the second test optotype a22 is started.

[0045] The LCD 3 displays both the background image a1 and the first test optotype a21. Even if the control unit 20 acquires an optotype switching signal at timing T1 during the test, the control unit 20 continues to display the first test optotype a21. The acquisition of this optotype switching signal triggers the control unit 20 to start generating the second test optotype a22. For example, a predetermined generation time G is required until the generation of the second test optotype a22 is completed.

[0046] The control unit 20 generates the second test optotype a22 while predicting the timing T3 at which the generation of the second test optotype a22 will be completed. For example, the control unit 20 may predict the timing T3 by using a correspondence table that associates the type of test optotype and visual acuity value with the corresponding generation time G. Such a correspondence table may be created in advance based on the results of experiments or simulations and stored in the memory 21.

[0047] Next, the control unit 20 sets timing T2 for erasing the first test optotype a21, taking into consideration a disappearance time D (e.g., 0.2 seconds) for allowing the subject to recognize the change from the first test optotype a21 to the second test optotype a22 and for which only the background image a1 is displayed on the LCD 3. For example, the time T2 is the time preceding timing T3 by the disappearance time D.

[0048] If the subject's visual acuity is not sufficiently high for the first test optotype a21 and the second test optotype a22 (in other words, if the subject's ability to interpret each test optotype is close to its limit), the subject may have difficulty recognizing the change in test optotype. For example, if the subject cannot clearly recognize the change in test optotype, they may be confused by the orientation of the gaps in the Landolt ring, which may hinder the test from proceeding smoothly. Furthermore, for some subjects, when the orientation of the gaps in the Landolt ring is changed, the sudden appearance of a white gap between the black lines may allow them to predict the orientation of the gaps, leading to a decrease in test accuracy. For this reason, in this embodiment, when the test optotype is changed, only the background image a1 is displayed on the LCD 3. By providing a disappearance time D, the change can be easily recognized even for test optotypes with high visual acuity values (i.e., small-sized test optotypes).

[0049] The disappearance time D is set to a length that allows the subject to recognize the disappearance of the test target without causing confusion or bother. For example, the disappearance time D may be 0.05 to 1.0 seconds, and preferably 0.1 to 0.5 seconds.

[0050] The control unit 20 displays the background image a1 and the first test optotype a21 in parallel with the generation of the second test optotype a22. When the set timing T2 arrives, the control unit 20 erases the first test optotype a21 and continues to display only the background image a1. The timing (timing T2) for erasing the display of the first test optotype a21 is set based on the timing (timing T3) at which the generation of the second test optotype a22 is completed. Therefore, the passage of the disappearance time D and the completion of the generation of the second test optotype a22 coincide (or nearly coincide) with timing T3. When the generation of the second test optotype a22 is completed, a completion signal indicating the completion of the generation of the second test optotype a22 is generated, and the second test optotype a22 is stored in RAM. The second test optotype a22 may be stored in another storage unit (e.g., memory 21).

[0051] When the control unit 20 receives a completion signal indicating that generation of the second test optotype a22 is completed, the control unit 20 causes the second test optotype a22 to be displayed on the LCD 3. For example, in this embodiment, the display of the second test optotype a22 starts immediately after the generation of the second test optotype a22 is completed. In this case, the timing T3 at which generation of the second test optotype a22 is completed and the timing T4 at which display of the second test optotype a22 starts coincide (or approximately coincide).

[0052] The same can be said for the case where the second test optotype a22 is switched to a third test optotype (not shown) and displayed on the LCD 3 based on an optotype switching signal from the LCD 41.

[0053] The above example illustrates that it takes a long time to generate a horizontal line optotype, a vertical line optotype, or a compacted optotype, etc., composed of multiple Landolt ring optotypes. However, it also takes a long time to generate a horizontal line optotype, a vertical line optotype, or a compacted optotype, etc., composed of multiple hiragana optotypes or multiple number optotypes. This is because, depending on the combination of hiragana optotypes and number optotypes, it is necessary to perform calculations to enlarge or reduce the reference images for multiple reference images. Even in such cases, the burden on the subject can be reduced by controlling the timing of switching between the current test optotype a2 and the next test optotype a2.

[0054] As described above, for example, the optotype presenting device of this embodiment continues to display the current first test optotype even after receiving a switching signal for switching from the first test optotype to the second test optotype, and displays the second test optotype after completing generation of the next second test optotype based on the switching signal. This shortens the non-display time during which neither the first test optotype nor the second test optotype is displayed on the LCD, thereby reducing the possibility of causing anxiety, confusion, annoyance, etc. to the subject.

[0055] Furthermore, for example, the optotype presenting device of this embodiment may display a background image after a predetermined time has elapsed since the first test optotype was displayed while the second test optotype was being generated based on a switching signal, and then display the second test optotype after the background image. For example, this may reduce the burden on the subject that may be caused by the prolonged generation of the test optotype, while allowing the subject to easily recognize the change in the test optotype. Furthermore, by temporally overlapping at least a portion of the generation of the second test optotype and the display of the background image, the test can be carried out efficiently.

[0056] Furthermore, for example, the optotype presenting device of this embodiment displays the background image after a predetermined time has elapsed since the first test optotype was displayed while the second test optotype was being generated based on the switching signal, and the timing at which the generation of the second test optotype is completed coincides with the timing at which the display of the background image is terminated, thereby displaying the second test optotype after the background image. This allows the subject to easily recognize the change in the test optotype using the background image, and can switch from the first test optotype to the second test optotype immediately after the generation of the second test optotype is completed. Therefore, there is no time when the LCD is not displayed, and there is no need to provide a separate time for displaying only the background image, making the test more efficient.

[0057] <Example of transformation> In this embodiment, an example has been described in which an optotype switching signal for switching the test optotype is output by the examiner operating the LCD 41 in the controller 4, but this is not limiting. In this embodiment, an optotype switching signal may be output based on the operation of the switch unit 40 in the controller 4. Of course, an optotype switching signal based on the operation may be output from either the LCD 41 or the switch unit 40.

[0058] In this embodiment, the first test target a21 is erased during the generation of the second test target a22, and the elapse of the disappearance time D in the background image a1 coincides with the timing T3 at which the second test target a22 is completed. However, the present invention is not limited to this. The first test target a21 may be erased after the generation of the second test target a22 is completed. Furthermore, the disappearance time D does not necessarily have to be set.

[0059] 5 and 6 are diagrams showing examples of variations in the timing of acquiring the optotype switching signal and switching the test optotype. Fig. 5 shows a case where the first test optotype a21 is erased after the generation of the second test optotype a22 is completed. Fig. 6 shows a case where no disappearance time D is provided during which only the background image a1 is displayed.

[0060] First, Fig. 5 will be described. When the control unit 20 receives a target switching signal at timing T1 during the test, it continues to display the first test target a21 and starts generating the second test target a22. When the generation of the second test target a22 is completed after the generation time G has elapsed (timing T3), it erases the display of the first test target a21 (timing T2) and displays only the background image a1 on the LCD 3. When the display of the background image a1 has elapsed for the disappearance time D, it starts displaying the second test target a22 (timing T4). In this configuration, timing T2 and timing T3 coincide (or approximately coincide).

[0061] For example, in the optotype presenting device of this embodiment, the display of the first test optotype a21 continues for the generation time G required to generate the second test optotype a22, and the background image a1 is displayed after the generation of the second test optotype a22 based on the optotype switching signal for switching the test optotype is completed. Furthermore, the second test optotype a22 is displayed after the display of the background image a1 has been displayed for the disappearance time D. This prevents the LCD 3 from being hidden during the generation of the test optotype, even if the generation of the test optotype takes time, thereby reducing the burden on the subject. Furthermore, by displaying only the background image a1 for the optimal disappearance time D after the generation of the second test optotype a22 is completed, the subject can easily recognize the change of the test optotype. Furthermore, since it is not necessary to predict the timing T3 at which the second test optotype a22 is completed and to set the timing T2 at which the display of the first test optotype a21 is erased, the complexity of the control performed by the control unit 20 is reduced. Although the configuration described above with reference to FIG. 3 requires complicated control, it can shorten the examination time, especially when the test optotypes for the subject's eye are frequently switched and displayed.

[0062] Next, Fig. 6 will be described. When the control unit 20 receives a target switching signal at timing T1 during the test, it continues to display the first test target a21 and starts generating the second test target a22. When the generation of the second test target a22 is completed after the generation time G has elapsed (timing T3), it erases the display of the first test target a21 (timing T2) and instantly starts displaying the second test target a22 (timing T4). In this configuration, timing T2, timing T3, and timing T4 coincide (or nearly coincide).

[0063] For example, when the first test optotype a21 and the second test optotype a22 are both Landolt ring optotypes, it is difficult for the subject to recognize the change in the test optotype. However, when either the first test optotype a21 or the second test optotype a22 is not a Landolt ring optotype (for example, a red-green optotype, a radiation optotype, a binocular vision function test optotype, etc.), the shape and size of the test optotype before and after the change are significantly different, making it easy for the subject to recognize the change in the test optotype.

[0064] Therefore, in the case of a combination in which the subject can easily recognize the change of the test optotype, the disappearance time D may not be set and the second test optotype a22 may be displayed on the LCD 3 immediately (in other words, for a time shorter than the disappearance time D). Of course, the disappearance time D may be set even for such an easy-to-recognize combination, and the second test optotype a22 may be displayed on the LCD 3 immediately even for a difficult-to-recognize combination. For example, the examiner may be allowed to arbitrarily select whether or not to set the disappearance time D. Alternatively, it may be determined in advance for each test optotype.

[0065] In the present embodiment, a configuration has been described in which the memory 21 built into the optotype presenting device 1 stores a reference image of the test optotype, an arithmetic expression for calculating the display size of the test optotype, and the like. However, the present invention is not limited to this. For example, the reference image and the arithmetic expression may be read from an external memory connectable to the optotype presenting device 1 (e.g., an SD card detachable from the device, a cloud capable of communicating with the device, etc.). In this case, the control unit 20 may read this data from the external memory and perform calculations based on the specified visual acuity value, the resolution of the LCD 3, the size of the reference image, and the like to generate the test optotype a2. The control unit 20 may also load the test optotype a2 into RAM or the memory 21 and display it on the LCD 3.

[0066] Although the present embodiment has been described with reference to a configuration in which a test optotype to be presented to the subject's eye is generated by enlarging or reducing a reference image of the test optotype, this is not limiting. In this embodiment, the test optotype a2 may be generated by further performing conversion and correction processes on the test optotype. For example, the conversion process may adjust the contrast of the test optotype, invert the background image a1 and the test optotype a2, or the like. For example, the correction process may take into account distortions and aberrations that may occur when light passes through an optical element, particularly in a configuration in which an optical element is disposed between the subject's eye and the LCD 3. Data such as correspondence tables and arithmetic expressions required for the conversion and correction processes may be read from the internal memory 21 or an external memory, and each process may be executed. The generation of the test optotype in the control unit 20 takes longer if additional conversion and correction processes are performed. However, even in such cases, the application of the present technology can reduce the burden on the subject.

[0067] In this embodiment, the optotype presenting device 1 is described as having a housing 2 and a controller 4, but the present invention is not limited to this. The optotype presenting device 1 may be used as a part of a subjective optometry device. That is, the optotype presenting device 1 may be used as an optotype presenting unit in a subjective optometry device. For example, the subjective optometry device may include a corrective optical system for correcting the subject's eye, and may be able to subjectively measure the optical characteristics of the subject's eye.

[0068] In this embodiment, an example has been described in which an optotype switching signal for switching the test optotype is issued based on the examiner's operation of the controller 4, but the present invention is not limited to this. For example, an optotype switching signal may be issued as appropriate in accordance with the progress of a visual acuity test program that automatically measures the visual acuity of the subject's eye, a self-eye examination program that automatically measures the optical characteristics of the subject's eye (e.g., spherical power, cylindrical power, astigmatism axis angle, etc.). In this case, the control unit 20 generates the test optotype a2 based on each optotype switching signal, and by appropriately controlling the timing of displaying the test optotype a2 on the LCD 3 (i.e., switching to the test optotype a2) relative to the timing of acquiring the optotype switching signal, the burden on the subject can be reduced. [Explanation of symbols]

[0069] 1. Visual target presentation device 2. Case 3 LCD 4 Controller 9 Inspection screen 20 Control Unit a1 background image a21 First test target a22 Second test target

Claims

1. An optotype presenting device for presenting an optotype to an eye to be examined, a display control means for displaying the test optotype on the display means; optotype generating means that starts generating the second test optotype based on a switching signal that switches the test optotype from the first test optotype to a second test optotype different from the first test optotype; Equipped with the display control means continues to display the first test optotype for a predetermined time even after acquiring the switching signal, and causes the second test optotype to be displayed at any timing after completion of generation of the second test optotype based on the switching signal; moreover, the display control means continues displaying the first test optotype for a generation time required for the optotype generation means to generate the second test optotype, displays a background image after generation of the second test optotype based on the switching signal is completed, and displays the second test optotype after the background image, the optotype presenting device being characterized in that

2. An optotype presenting device for presenting an optotype to an eye to be examined, comprising: a display control means for displaying the test optotype on the display means; optotype generating means that starts generating the second test optotype based on a switching signal that switches the test optotype from the first test optotype to a second test optotype different from the first test optotype; Equipped with the display control means continues to display the first test optotype for a predetermined time even after acquiring the switching signal, and causes the second test optotype to be displayed at any timing after completion of generation of the second test optotype based on the switching signal; moreover, the display control means, during generation of the second test optotype based on the switching signal, causes a background image to be displayed after the predetermined time has elapsed, and causes the second test optotype to be displayed after the background image.

3. 3. The optotype presenting device according to claim 2, the display control means causes the timing of ending the display of the background image to coincide with the timing of completion of generation of the second test optotype, and causes the second test optotype to be displayed after the background image.

4. An optotype presentation program for use in an optotype presentation device for presenting an optotype to an eye to be examined, comprising: When executed by a processor of the visual target presenting device, a display control step of displaying the test optotype on a display means; an optotype generating step of starting generation of the second test optotype based on a switching signal for switching the test optotype from the first test optotype to a second test optotype different from the first test optotype; causing the target presenting device to execute the display control step continues displaying the first test optotype for a predetermined time even after the switching signal is acquired, and displays the second test optotype at any timing after generation of the second test optotype based on the switching signal is completed; moreover, the display control step continues displaying the first test optotype for a generation time period that is a generation time required for the optotype generation step to generate the second test optotype, displays a background image after generation of the second test optotype based on the switching signal is completed, and displays the second test optotype after the background image.

5. An optotype presentation program for use in an optotype presentation device for presenting an optotype to a subject's eye, comprising: When executed by a processor of the visual target presenting device, a display control step of displaying the test optotype on a display means; an optotype generating step of starting generation of the second test optotype based on a switching signal for switching the test optotype from the first test optotype to a second test optotype different from the first test optotype; causing the target presenting device to execute the display control step continues displaying the first test optotype for a predetermined time even after the switching signal is acquired, and displays the second test optotype at any timing after generation of the second test optotype based on the switching signal is completed; moreover, the display control step is performed during generation of the second test optotype based on the switching signal, and after the predetermined time has elapsed, a background image is displayed, and the second test optotype is displayed after the background image.

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