JP7639495B2 - Visual Field Assessment Device - Google Patents

Description

The present invention relates to a visual field evaluation device.

A visual field evaluation device is known that displays an index on a display unit to detect the subject's line of sight and evaluates the subject's visual field based on the detection results (see, for example, Patent Document 1).

Patent No. 6606264

When using a visual field evaluation device like the one described above for evaluation, even accidentally reaching a displayed target is considered gazing at the target, making it difficult to obtain an appropriate evaluation.

The present invention has been made in consideration of the above, and aims to provide a visual field assessment device that can appropriately assess a subject's visual field.

The visual field evaluation device according to the present invention includes a display unit, a viewpoint detection unit that detects the position of the subject's viewpoint on the display unit, a display control unit that causes the display unit to display a reference indicator and a target indicator at a position away from the reference indicator, an area setting unit that sets a movement determination area between the reference indicator and the target indicator on the display unit, and an evaluation unit that evaluates the visual field of the subject based on the positional relationship between the reference indicator and the target indicator, and the evaluation unit evaluates the visual field of the subject based on whether the subject's viewpoint has moved through the movement determination area.

The present invention provides a visual field assessment device that can appropriately assess a subject's visual field.

FIG. 1 is a diagram showing an example of a visual field evaluation device according to the present embodiment. FIG. 2 is a functional block diagram illustrating an example of a visual field evaluation device. FIG. 3 is a diagram showing an example of the display content on the display unit. FIG. 4 is a diagram showing an example of the display content on the display unit. FIG. 5 is a diagram showing another example of the display content on the display unit. FIG. 6 is a diagram showing another example of the display content on the display unit. FIG. 7 is a flowchart showing an example of a visual field evaluation method according to this embodiment. FIG. 8 is a flowchart showing an example of the visual field detection process in this embodiment. FIG. 9 is a flowchart showing an example of the visual field evaluation process according to this embodiment.

Below, an embodiment of the visual field assessment device according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to this embodiment. Furthermore, the components in the following embodiment include those that are easily replaceable by a person skilled in the art, or those that are substantially the same.

Figure 1 is a diagram showing an example of a visual field assessment device 100 according to this embodiment. The visual field assessment device 100 shown in Figure 1 detects the gaze of a subject and evaluates the subject's visual field by using the detection result. The visual field assessment device 100 can detect the gaze of a subject using various methods, such as a method of detecting the gaze based on the position of the subject's pupil and the position of the corneal reflection, or a method of detecting the gaze based on the position of the subject's inner corner of the eye and the position of the iris.

As shown in FIG. 1, the visual field evaluation device 100 includes a display device 10, an eyeball imaging device 20, a control device 30, an output device 40, and an input device 50.

The display device 10 includes a flat panel display such as a liquid crystal display (LCD) or an organic electroluminescence display (OLED). In this embodiment, the display device 10 has a display unit 11. The display unit 11 displays information such as images. The display device 10 may be a head-mounted display device. When the display device 10 is a head-mounted display device, a configuration such as an eye imaging device 20 is disposed within a head-mounted module.

The eyeball photographing device 20 photographs the left and right eyeballs EB of the subject to obtain eyeball images, and transmits the obtained eyeball images to the control device 30. The eyeball photographing device 20 obtains image data by photographing the left and right eyeballs EB of the subject. The eyeball photographing device 20 has various cameras according to the method of detecting the subject's line of sight. For example, in the case of a method of detecting the line of sight based on the position of the subject's pupil and the position of the corneal reflection image, the eyeball photographing device 20 has an infrared camera, and has an optical system that can transmit near-infrared light with a wavelength of 850 [nm], for example, and an image sensor that can receive the near-infrared light. Note that this configuration may be configured to include an irradiation device that irradiates the subject's eyeball EB with infrared rays. Also, in the case of a method of detecting the line of sight based on the position of the subject's inner corner and the position of the iris, for example, the eyeball photographing device 20 has a visible light camera. The eyeball photographing device 20 outputs a frame synchronization signal. The period of the frame synchronization signal can be, for example, 20 [msec], but is not limited to this. The eyeball imaging device 20 can be configured as, for example, a stereo camera having two cameras, but is not limited to this.

The control device 30 comprehensively controls the operation of the visual field evaluation device 100. The control device 30 includes a calculation processing device such as a CPU (central processing unit) and a storage device such as a memory or storage device, such as a ROM (read only memory) and a RAM (random access memory). The control device 30 causes the calculation processing device to carry out calculations according to a computer program stored in the storage device.

In the visual field evaluation device 100 according to this embodiment, the display device 10 and the control device 30 are separate devices. The display device 10 and the control device 30 may be integrated. For example, the visual field evaluation device 100 may include a tablet-type personal computer. In this case, the tablet-type personal computer may be equipped with a display device, an eyeball imaging device, a computer system, an input device, an output device, etc.

The output device 40 includes a display device such as a flat panel display. The output device 40 may also include an audio output device and a printing device. The input device 50 generates input data when operated. The input device 50 includes a keyboard or a mouse for a computer system. The input device 50 may also include a touch sensor provided on the display unit of the output device 40, which is a display device.

Figure 2 is a functional block diagram showing an example of a visual field evaluation device 100. As shown in Figure 2, the control device 30 has a display control unit 31, a viewpoint detection unit 32, a region setting unit 33, a determination unit 34, a calculation unit 35, an evaluation unit 36, an input/output control unit 37, and a memory unit 38.

The display control unit 31 causes the display unit 11 to display an index for the subject to gaze at. The display control unit 31 causes the display unit 11 to display a reference index. The reference index indicates the position that is the center of the visual field when evaluating the visual field of the subject. The display control unit 31 can display the reference index, for example, at the center of the display unit 11 or at an end such as a corner. The display control unit 31 causes the display unit 11 to display a target index at a position away from the reference index. The display control unit 31 displays an index at an appropriate position when evaluating the visual field of the subject. The display control unit 31 may calculate an appropriate position based on evaluation information that has been measured in the past and stored in the storage unit 38, for example. After displaying the reference index, if the subject gazes at the reference index for a predetermined period of time or more, that is, if the subject's gaze is on the reference index for a predetermined period of time or more. The display control unit 31 may display the reference index and the target index on the display unit 11 by playing back the evaluation content.

The viewpoint detection unit 32 detects the position of the subject's viewpoint. In this embodiment, the viewpoint detection unit 32 detects the subject's gaze vector defined in a three-dimensional global coordinate system based on images of the subject's left and right eyes EB acquired by the eyeball imaging device 20. The viewpoint detection unit 32 detects the position of the intersection between the detected gaze vector of the subject and the display unit 11 of the display device 10 as the position of the subject's viewpoint. In other words, in this embodiment, the position of the viewpoint is the position of the intersection between the gaze vector of the subject defined in a three-dimensional global coordinate system and the display unit 11 of the display device 10. The viewpoint detection unit 32 detects the position of the subject's gaze position at every specified sampling period. This sampling period can be, for example, the period of the frame synchronization signal output from the eyeball imaging device 20 (for example, every 20 [msec]).

The area setting unit 33 sets a movement judgment area between the reference index and the target index on the display unit 11. The movement judgment area is set to a portion that is the shortest path for moving the viewpoint from the reference index to the target index when a subject gazing at the reference index can visually recognize the target index. The area setting unit 33 also sets a reach judgment area in the portion where the target index is displayed. The area setting unit 33 also sets a gaze judgment area in the portion where the reference index is displayed. Hereinafter, the movement judgment area, reach judgment area, and gaze judgment area may be collectively referred to as a "judgment area." In this embodiment, the judgment area set by the area setting unit 33 is not displayed on the display unit 11 as a general rule. Note that the judgment area may be displayed on the display unit 11, for example, under the control of the display control unit 31.

The determination unit 34 determines whether or not the viewpoint is present in the determination area corresponding to the index based on the position of the viewpoint during the period in which the index is displayed by the display control unit 31, and outputs the determination result. The determination unit 34 determines whether or not the viewpoint is present in the determination area at each specified determination cycle. The determination cycle can be, for example, the cycle of the frame synchronization signal output from the eye imaging device 20 (e.g., every 20 msec). In other words, the determination cycle of the determination unit 34 is the same as the sampling cycle of the viewpoint detection unit 32. The determination unit 34 makes a determination about the viewpoint each time the viewpoint position is sampled by the viewpoint detection unit 32, and outputs the determination result.

Based on the judgment result of the judgment unit 34, the calculation unit 35 performs calculations on the progress of the movement of the viewpoint during the period in which the judgment area is set. The calculation unit 35 has a timer that detects the elapsed time from a predetermined point in time, and a counter that counts the number of judgments that the judgment unit 34 judges that the viewpoint exists in the judgment area. As for the timers, for example, a timer T0 that manages the playback time of the evaluation content on the display unit 11, and a timer T1 that detects the elapsed time since the target indicator is displayed on the display unit 11 are provided. A counter is set for each judgment area. In this embodiment, a counter (CNT0) that counts the number of judgments of the viewpoint in the gaze judgment area, a counter (CNT1) that counts the number of judgments of the viewpoint in the movement judgment area, and a counter (CNT2) that counts the number of judgments of the viewpoint in the arrival judgment area are provided. The count values of the counters CNT0, CNT1, and CNT2 indicate the time during which the viewpoint exists in each judgment area. A larger count value indicates a longer time that the viewpoint was in the judgment area, and a smaller count value indicates a shorter time that the viewpoint was in the judgment area.

When the value of counter CNT0 for the gaze determination area is equal to or greater than a predetermined value, it can be determined that the subject has gazed at the reference indicator. Furthermore, when the value of counter CNT1 for the movement determination area is equal to or greater than a predetermined value, it can be determined that the subject's gaze has moved through the movement determination area. Furthermore, when the value of counter CNT2 for the reach determination area is equal to or greater than a predetermined value, it can be determined that the subject's gaze has reached the target indicator.

The evaluation unit 36 evaluates the subject's visual field based on the subject's viewpoint data. In this embodiment, the subject's visual field is the visible area of the subject. For example, when the subject's viewpoint moves from the reference indicator through the movement determination area to reach the target indicator, that is, when the values of counters CNT1 and CNT2 are each equal to or greater than a predetermined value, the evaluation unit 36 evaluates that the display position of the target indicator is included in the subject's visible area centered on the reference indicator.

In addition, for example, if the subject's gaze point does not reach the target indicator, that is, if the value of counter CNT2 is not equal to or greater than a predetermined value, the evaluation unit 36 evaluates that the display position of the target indicator is not included in the visible area.

Furthermore, if the subject's viewpoint reaches the target indicator without moving through the movement determination area, that is, if the value of counter CNT1 is not equal to or greater than a predetermined value but the value of counter CNT2 is equal to or greater than a predetermined value, the evaluation unit 36 evaluates that there is a possibility that the display position of the target indicator is not included in the visible area. Note that, if the subject's viewpoint reaches the target indicator without moving through the movement determination area, the evaluation unit 36 may perform an evaluation based on viewpoint data when, for example, the target indicator is displayed again at the same position.

In the second evaluation, if the subject's viewpoint moves from the reference indicator through the movement determination area to the target indicator, the evaluation unit 36 evaluates that the display position of the target indicator is included in the subject's visible area centered on the reference indicator. If the subject's viewpoint does not move to the target indicator, the evaluation unit 36 evaluates that the display position of the target indicator is not included in the visible area. If the subject's viewpoint reaches the target indicator without moving through the movement determination area, the evaluation unit 36 evaluates that there is a possibility that the display position of the target indicator is not included in the visible area.

The input/output control unit 37 acquires data (image data of the eye EB, input data, etc.) from at least one of the eyeball imaging device 20 and the input device 50. The input/output control unit 37 also outputs data to at least one of the display device 10 and the output device 40. The input/output control unit 37 may output the evaluation results from the output device 40.

The storage unit 38 stores the above-mentioned judgment results and evaluation results. The storage unit 38 also stores a visual field evaluation program that causes a computer to execute the following processes: detecting the position of the subject's viewpoint on the display unit 11; displaying a reference indicator on the display unit 11 and a target indicator at a position away from the reference indicator; setting a movement determination area on the display unit 11 between the reference indicator and the target indicator; and evaluating the subject's visual field based on whether the subject's viewpoint has moved through the movement determination area.

Next, a visual field evaluation method according to this embodiment will be described. In the visual field evaluation method according to this embodiment, the visual field evaluation device 100 described above is used to evaluate the visual field of the subject.

3 and 4 are diagrams showing an example of the display contents on the display unit 11. As shown in FIG. 3, the display control unit 31 displays the reference index P so that the subject's gaze is directed to the center of the display unit 11, for example. The reference index P is the center of the visual field when evaluating the visual field of the subject. The dashed line portion in FIG. 3 is an example of the display position of the target index Q displayed with the reference index P as the reference position. At the stage shown in FIG. 3, the target index Q is not displayed. The area setting unit 33 sets the gaze determination area S0 in the part where the reference index P is displayed. The gaze determination area S0 may be a shape corresponding to the shape of the reference index P, such as a shape along the outline of the reference index P, or may be a shape different from the shape of the reference index P, such as a circle or a rectangle. After the gaze determination area S0 is set, the gaze detection unit 32 detects the position of the subject's gaze. The determination unit 34 determines whether the detected gaze of the subject is present in the gaze determination area S0. The calculation unit 35 determines that the subject is gazing at the reference index P when the subject's gaze is present in the gaze determination area S0 for a predetermined period of time or more, that is, when the value of the counter CNT0 is equal to or greater than a predetermined threshold value.

When the calculation unit 35 determines that the gaze point is in the gaze determination area S0 for a predetermined period of time or more, the display control unit 31 displays the target index Q at a position away from the position of the reference index P, as shown in FIG. 4. The display control unit 31 can, for example, randomly select one position from the positions indicated by the dashed lines in FIG. 3 and display the target index Q.

When the target indicator Q is displayed, the region setting unit 33 sets a movement determination region S1 extending in a linear direction between the reference indicator P and the target indicator Q. The movement determination region S1 is formed, for example, in a band shape with a uniform dimension in the width direction (direction perpendicular to the linear direction). Note that the width direction dimension of the movement determination region S1 is not limited to a configuration with a uniform configuration in the linear direction. The width direction dimension of the movement determination region S1 is set, for example, to correspond to the dimensions in the same direction of the reference indicator P and the target indicator Q. For example, the width direction dimension of the movement determination region S1 can be set based on the trajectory of the subject's movement of the viewpoint in a past evaluation. In addition, the region setting unit 33 sets a reach determination region S2 in the part where the target indicator Q is displayed. The reach determination region S2 may be a shape corresponding to the shape of the reference indicator P, such as a shape following the outline of the target indicator Q, or may be a shape different from the shape of the target indicator Q, such as a circle or a rectangle.

After the movement determination area S1 and the arrival determination area S2 are set, the viewpoint detection unit 32 detects the position of the subject's viewpoint. The determination unit 34 determines whether the detected subject's viewpoint is in the movement determination area S1 and the arrival determination area S2. The calculation unit 35 calculates the time the subject's viewpoint is in the movement determination area S1 and the arrival determination area S2 based on the determination result. If the subject's viewpoint is in the arrival determination area S2 for a predetermined time or more, that is, if the value of the counter CNT2 is equal to or greater than a predetermined threshold, the calculation unit 35 determines that the subject's viewpoint has reached the target index Q. In addition, if the calculation unit 35 determines that the subject's viewpoint has reached the target index Q, it determines whether the movement determination area S1 has moved. If the subject's viewpoint is in the movement determination area S1 for a predetermined time or more, that is, if the value of the counter CNT2 is equal to or greater than a predetermined threshold, the calculation unit 35 determines that the subject has moved the movement determination area S1.

As shown in FIG. 4, when a subject gazing at the reference index P can visually recognize the target index Q, the subject tends to move the viewpoint from the reference index P to the target index Q along a trajectory R1 along the shortest route. In contrast, when a subject gazing at the reference index P cannot visually recognize the target index Q, the subject either barely moves the viewpoint from the reference index P or tries to move the viewpoint in an arbitrary direction in search of the target index Q. When the subject is able to visually recognize the target index Q as a result of moving the viewpoint in an arbitrary direction, the subject tries to move the viewpoint from the destination to the target index Q as shown by the trajectory R2. A subject who moves the viewpoint as shown by the trajectory R2 may be able to move the viewpoint to the target index Q, but may not be able to visually recognize the target index Q when the reference index P is the center of the visual field. By determining whether the subject's viewpoint has moved through the movement determination area S1, it is possible to highly accurately evaluate a subject who cannot visually recognize the target index Q when the reference index P is the center of the visual field.

The movement determination area S1 may be divided into a plurality of areas in a linear direction, and the time during which the subject's gaze was present may be determined for each divided area. In this configuration, the movement of the subject's gaze along the movement determination area S1 from the reference index P to the target index Q can be detected with higher accuracy. When the movement determination area S1 is divided into a plurality of areas in a linear direction, the movement determination area S1 may be weighted for each area, for example, by placing emphasis on the gaze's presence time in an area close to the reference index P, or on the gaze's presence time in an area close to the target index Q. The movement determination area S1 may be set in a part of the area between the reference index P and the target index Q. The movement determination area S1 may be set in an area of the display unit 11 excluding the movement determination area S1, and when the time during which the subject's gaze is present in the determination area is less than a predetermined time, it may be determined that the subject's gaze has moved through the movement determination area S1.

When the values of counters CNT1 and CNT2 are equal to or greater than a predetermined value, such as when the subject moves the viewpoint along trajectory R1, the evaluation unit 36 evaluates that the display position of target index Q is included in the visible area. In addition, when the value of counter CNT2 is not equal to or greater than the predetermined value, the evaluation unit 36 evaluates that the display position of target index Q is not included in the visible area.

In addition, if the value of counter CNT1 is not equal to or greater than a predetermined value but the value of counter CNT2 is equal to or greater than a predetermined value, for example when the subject moves the viewpoint along trajectory R2, the evaluation unit 36 evaluates that there is a possibility that the display position of target indicator Q is not included in the viewable area of the subject. In addition, if the value of counter CNT1 is not equal to or greater than a predetermined value but the value of counter CNT2 is equal to or greater than a predetermined value, the evaluation unit 36 performs evaluation based on the viewpoint data when target indicator Q is displayed again at the same position.

When the target index Q is displayed and the evaluation is performed again, if the values of counters CNT1 and CNT2 are each equal to or greater than a predetermined value, the evaluation unit 36 can evaluate that the display position of the target index Q is included in the visible area. Furthermore, if the value of counter CNT2 is not equal to or greater than the predetermined value, the evaluation unit 36 can evaluate that the display position of the target index Q is not included in the visible area. Furthermore, if the value of counter CNT1 is not equal to or greater than the predetermined value but the value of counter CNT2 is equal to or greater than the predetermined value, the evaluation unit 36 evaluates that there is a possibility that the display position of the target index Q is not included in the subject's visible area.

After evaluating one target index Q, the display control unit 31 displays the reference index P again, and displays the target index Q in another position. Then, in the same manner as above, the viewpoint detection unit 32 detects the subject's viewpoint, the area setting unit 33 sets a judgment area, and the judgment unit 34 judges whether the viewpoint is present in the judgment area. The calculation unit 35 also calculates the subject's viewpoint data, and the evaluation unit 36 evaluates whether the display position of the target index Q is included in the visible area based on the viewpoint data.

Figure 5 is a diagram showing another example of the display contents on the display unit 11. As shown in Figure 5, when displaying the reference indicator P, the display control unit 31 may display the reference indicator P not only at the center of the display unit 11, but also at the end of the display unit 11, such as the corner 11a of the display unit 11. The dashed line portion in Figure 5 is an example of the display position of the target indicator Q displayed with the reference indicator P as the reference position. In the example shown in the dashed line portion in Figure 5, the target indicator Q is set to be displayed at a position farther away from the center in the left-right direction and the up-down direction than the reference indicator P displayed at the corner 11a of the display unit 11. When the reference indicator P is placed at the end of the display unit 11, a larger distance can be secured in the direction opposite the end compared to the case where the reference indicator P is displayed at the center of the display unit 11 and its vicinity. Therefore, it is possible to perform evaluation on a wider range of the visible area of the subject.

Figure 6 is a diagram showing another example of the display content on the display unit 11. As shown in Figure 6, when displaying the reference index P, the display control unit 31 is not limited to displaying it at the center or end of the display unit 11, but can display it at any position on the display unit 11, for example. For example, if it is difficult for a subject to look at the center for some reason but the subject is gazing at a point on the screen, the point on the screen that the subject is gazing at can be set as the reference optotype P1, and a target optotype Q1 can be displayed relative to the reference optotype P1, thereby making it possible to perform visual field measurement even for subjects who have difficulty gazing intently at the center of the screen.

Next, an example of a visual field evaluation method according to this embodiment will be described with reference to Figs. 7 to 9. Figs. 7 to 9 are flowcharts showing an example of a visual field evaluation method according to this embodiment. The display control unit 31 starts playing the evaluation content (step S101). The evaluation content including the reference index P is displayed on the display unit 11 of the display device 10 as shown in Fig. 3. The calculation unit 35 resets a timer T0 that manages the playback time of the evaluation content (step S102).

The calculation unit 35 resets the count values of the counters CNT0, CNT1, and CNT2 to 0, and the area setting unit 33 sets the gaze determination area S0 on the reference index P (step S103). The viewpoint detection unit 32 detects the position data of the subject's viewpoint on the display unit 11 of the display device 10 at a specified sampling period (e.g., 20 msec) (step S104).

The calculation unit 35 determines whether or not the detection of the gaze point has failed, taking into consideration cases where the gaze point cannot be detected due to blinking, etc. (step S105). If the calculation unit 35 determines that the detection of the gaze point has failed (Yes in step S105), it resets the value of counter CNT0 to 0 (step S106) and proceeds to step S118, which will be described later. If the calculation unit 35 determines that the detection of the gaze point has not failed (No in step S105), it proceeds to step S107.

When it is determined that the detection of the viewpoint has not failed (No in step S105), the calculation unit 35 determines whether the count value of the counter CNT0 is equal to or greater than a threshold value (step S107). When it is determined that the count value of the counter CNT0 is equal to or greater than a predetermined value (Yes in step S107), the calculation unit 35 resets the count value of the counter CNT0 to 0 (step S108), resets the timer T1 (step S109), displays the target index Q on the display unit 11 (step S110), starts the timer T1 (step S111), and proceeds to step S118.

When it is determined that the count value of counter CNT0 is not equal to or greater than the threshold value (No in step S107), the calculation unit 35 determines whether timer T1 is greater than 0 and within a predetermined value (step S112). When it is determined that timer T1 is greater than 0 and within a predetermined value (Yes in step S112), the calculation unit 35 performs a visual field detection process (described later) (step S113) and then proceeds to step S118.

When the calculation unit 35 determines that the timer T1 is 0 or exceeds a predetermined value (No in step S112), it determines whether or not the visual field detection process described below is being performed (step S114). When the calculation unit 35 determines that the visual field detection process is being performed (Yes in step S114), it performs the visual field evaluation process (step S115) and then proceeds to step S118.

When the calculation unit 35 determines that visual field detection processing has not been performed (No in step S114), it determines whether or not the subject's gaze is present in the gaze determination area S0 (step S116). When the calculation unit 35 determines that the subject's gaze is present in the gaze determination area S0 (Yes in step S116), it increments the count value of the counter CNT0 by +1 (step S117) and proceeds to step S118.

If the calculation unit 35 determines that the subject's gaze point is not present in the gaze determination area S0 (No in step S116), the calculation unit 35 proceeds to step S118.

In step S118, the calculation unit 35 determines whether or not the time for completing the playback of the evaluation content has arrived based on the detection result of the timer T0 (step S118). If the calculation unit 35 determines that the time for completing the playback of the evaluation content has not arrived (No in step S118), the process from step S104 onwards is repeated.

When the calculation unit 35 determines that the time for completing the playback of the evaluation content has arrived (Yes in step S118), the display control unit 31 stops the playback of the evaluation content (step S119). The evaluation unit 36 outputs the evaluation result based on the viewpoint data obtained from the above processing result (step S120). This ends the processing.

Figure 8 is a flowchart showing an example of visual field detection processing. As shown in Figure 8, in the visual field detection processing, the calculation unit 35 sets a movement determination area S1 and a reach determination area S2 (step S201). The calculation unit 35 determines whether the subject's viewpoint is in the movement determination area S1 (step S202). If the calculation unit 35 determines that the subject's viewpoint is in the movement determination area S1 (Yes in step S202), it increments the count value of the counter CNT1 by +1 (step S203) and ends the processing.

The calculation unit 35 determines whether the subject's viewpoint is in the reach determination area S2 (step S204). If the calculation unit 35 determines that the subject's viewpoint is in the reach determination area S2 (Yes in step S204), it increments the count value of the counter CNT2 by +1 (step S205) and ends the process. If the calculation unit 35 determines that the subject's viewpoint is not in the reach determination area S2 (No in step S204), it ends the process.

Figure 9 is a flowchart showing an example of visual field evaluation processing. As shown in Figure 9, in the visual field evaluation processing, the evaluation unit 36 determines whether or not the evaluation result has been calculated (step S301). When the evaluation unit 36 determines that the evaluation result has been calculated (Yes in step S301), it ends the processing.

When the evaluation unit 36 determines that the evaluation result has not been calculated (No in step S301), it determines whether the count value of the counter CNT2 is equal to or greater than a predetermined value (step S302). When the evaluation unit 36 determines that the count value of the counter CNT2 is not equal to or greater than the predetermined value (No in step S302), it evaluates that the display position of the target index Q is not included in the visible area (indicated as "evaluation ×" in FIG. 9) (step S303), and ends the process.

When the evaluation unit 36 determines that the count value of the counter CNT2 is equal to or greater than a predetermined value (Yes in step S302), it determines whether the count value of the counter CNT1 is equal to or greater than a predetermined value (step S304). When the evaluation unit 36 determines that the count value of the counter CNT1 is not equal to or greater than the predetermined value (No in step S304), it evaluates that there is a possibility that the display position of the target index Q is not included in the visible area (indicated as "evaluation △" in FIG. 9) (step S305), and ends the process. Note that when the evaluation is △, the target index Q is displayed at the same position and the visual field detection process is performed again, and when the visual field evaluation process for the second visual field detection process is △, when the evaluation result is output in step S120 in FIG. 7, a note may be displayed indicating that the target index Q was able to be gazed at, but that there is a high possibility that the display position of the target index Q is not included in the visible area.

When the evaluation unit 36 determines that the count value of the counter CNT1 is equal to or greater than a predetermined value (Yes in step S304), it evaluates that the display position of the target indicator Q is included in the visible area (indicated as "evaluation good" in FIG. 9) (step S306), and ends the process.

As described above, the visual field evaluation device 100 according to this embodiment includes a display unit 11, a viewpoint detection unit 32 that detects the position of the subject's viewpoint on the display unit 11, a display control unit 31 that causes the display unit 11 to display a reference index P and a target index Q at a position away from the reference index P, an area setting unit 33 that sets a movement determination area S1 between the reference index P and the target index Q on the display unit 11, and an evaluation unit 36 that evaluates the subject's visual field based on the positional relationship between the reference index P and the target index Q, and the evaluation unit 36 evaluates the subject's visual field based on whether the subject's viewpoint has moved through the movement determination area S1.

With this configuration, the subject's field of view is evaluated based on whether the subject's viewpoint has moved through the movement determination area S1, which reduces the influence of chance and makes it possible to appropriately evaluate the subject's field of view.

In the visual field evaluation device 100 according to this embodiment, the area setting unit 33 sets the arrival determination area S2 in the portion where the target index Q is displayed, and the evaluation unit 36 evaluates that, when the subject's viewpoint moves through the movement determination area S1 and reaches the arrival determination area S2 within a predetermined time, the display position of the target index Q is included in the subject's visible area centered on the reference index P. With this configuration, in addition to the subject's viewpoint reaching the arrival determination area S2 within the predetermined time, the display position of the target index Q is evaluated to be included in the subject's visible area when the movement determination area S1 is moved, so that evaluation can be performed except when the arrival determination area S2 is reached by chance. This allows the subject's visual field to be evaluated with high accuracy.

In the visual field evaluation device 100 according to this embodiment, the evaluation unit 36 evaluates that if the subject's viewpoint reaches the reach determination area S2 within a predetermined time without moving through the movement determination area S1, the display position of the target index Q may not be included in the visible area of the subject. With this configuration, even if the subject's viewpoint reaches the reach determination area S2 within a predetermined time, if the movement determination area S1 is moved, the display position of the target area is evaluated as being included in the visible area, whereas if the movement determination area S1 is not moved, the reach determination area S2 may have been reached by chance, and the display position of the target index Q may not be included in the visible area, making it possible to differentiate between evaluations. This allows the subject's visual field to be evaluated with high accuracy.

In the visual field evaluation device 100 according to this embodiment, the area setting unit 33 sets a gaze determination area S0 in the portion where the reference index P is displayed, and the display control unit 31 displays the target index Q when the subject's gaze is in the gaze determination area S0 for a predetermined period of time or more. With this configuration, the target index Q is displayed after it is detected that the subject has gazed at the reference index P, so that the subject's visual field can be evaluated with high accuracy.

In the visual field evaluation device 100 according to this embodiment, the display control unit 31 displays a reference index P at an end of the display unit 11, and displays a target index Q at a position away from the end of the display unit 11 relative to the reference index P. With this configuration, when the display unit 11 is used, the range of the visual field that can be evaluated can be expanded.

The technical scope of the present invention is not limited to the above-described embodiments, and appropriate modifications can be made without departing from the spirit of the present invention.

CNT0, CNT1, CNT2...counter, EB...eyeball, P...reference index, Q...target index, R1, R2...trajectory, S0...gaze determination area, S1...movement determination area, S2...reach determination area, T0, T1...timer, 10...display device, 11...display unit, 11a...corner, 20...eyeball imaging device, 30...control device, 31...display control unit, 32...viewpoint detection unit, 33...area setting unit, 34...determination unit, 35...calculation unit, 36...evaluation unit, 37...input/output control unit, 38...storage unit, 40...output device, 50...input device, 100...visual field evaluation device

Claims (4)

A display unit;
a viewpoint detection unit that detects a position of a viewpoint of a subject on the display unit;
a display control unit that causes the display unit to display a reference indicator and a target indicator at a position spaced apart from the reference indicator;
a region setting unit that sets a movement determination region between the reference index and the target index in the display unit and sets an arrival determination region in a portion where the target index is displayed;
an evaluation unit that evaluates the visual field of the subject based on a positional relationship between the reference index and the target index,
A visual field evaluation device, wherein the evaluation unit evaluates that, if the subject's viewpoint reaches the reach determination area within a predetermined time without moving through the movement determination area, there is a possibility that the display position of the target indicator is not included in the subject's visible area centered on the reference indicator. The visual field evaluation device of claim 1, wherein the evaluation unit evaluates that, when the subject's viewpoint moves through the movement determination area and reaches the reach determination area within a predetermined time, the display position of the target indicator is included in the subject's visible area centered on the reference indicator. The region setting unit sets a gaze determination region in a portion where the reference indicator is displayed,
The visual field evaluation device according to claim 1 , wherein the display control unit causes the target indicator to be displayed when the gaze point of the subject is present in the gaze determination area for a predetermined period of time or more. The visual field evaluation device according to claim 1 , wherein the display control unit displays the reference index at an end of the display unit, and displays the target index at a position away from the end of the display unit with respect to the reference index.

Images