Visual field range determination device and visual field range determination method

Abstract

This visual field range determination device comprises a display, a display control unit, an electroencephalograph, a frequency component detection unit, and a determination unit. The display has a display screen including a plurality of display cells arranged in a two-dimensional array. The display control unit performs light emission control for the display screen. The electroencephalograph measures a brain wave signal of a subject induced by visual stimulation through light emission. The frequency component detection unit detects a frequency component of the brain wave signal. The determination unit determines a visual field range of the subject. The display control unit causes a first display cell to blink at a first blinking frequency and causes a second display cell, which is different from the first display cell, to blink at a second blinking frequency, which is different from the first blinking frequency, among the plurality of display cells. The determination unit determines the visual field range of the subject from a blinking frequency of a visual field determination light emission pattern in the plurality of display cells and the frequency component of the brain wave signal.

Description

Visual field range determination device and visual field range determination method

[0001] The present invention relates to a technique for determining a visual field range related to visual abnormalities and the like.

[0002] Various techniques for measuring visual fields have been put to practical use, such as Humphrey perimeters and Goldmann perimeters. Furthermore, as a device for measuring visual fields, for example, a perimeter as shown in Cited Document 1 has been devised.

[0003] The perimeter of the cited document 1 detects the subject's response to a visual stimulus by inputting a subject response switch. The perimeter of the cited document 1 includes a subject response detection device as an alternative to the subject response switch. The subject response detection device detects the subject's response to the visual stimulus by detecting a visual evoked potential.

[0004] Japanese Unexamined Patent Publication No. 4-285526

[0005] However, conventional perimeters such as those disclosed in the cited document 1 have problems such as erroneous determination of the position of visual abnormalities in visual field measurement and reduced measurement accuracy.

[0006] Therefore, the present invention aims to measure the visual field with higher accuracy.

[0007] A visual field range determination device according to one embodiment of the present invention includes a display, a display control unit, an electroencephalograph, a frequency component detection unit, and a determination unit. The display has a display screen configured with a plurality of display cells arranged two-dimensionally. The display control unit controls light emission of the display screen. The electroencephalograph measures electroencephalogram signals of a subject generated by visual stimulation using light emission. The frequency component detection unit determines the visual field range of the subject.

[0008] The display control unit causes a first display cell among the plurality of display cells to blink at a first blinking frequency, and causes a second display cell different from the first display cell to blink at a second blinking frequency different from the first blinking frequency. The determination unit determines the visual field range of the subject from the blinking frequency of the light emitting pattern for visual field determination in the plurality of display cells and the frequency component of the electroencephalogram signal.

[0009] In this configuration, the visual field range is determined based on the frequency components of the electroencephalogram signal that are potentially generated according to the frequency of the visual stimulus. At this time, since the blinking frequencies of at least consecutive display cells are different, the frequency components of the electroencephalogram signal corresponding to these are discriminated with high accuracy. Therefore, it is possible to accurately identify whether the subject was able to visually recognize the blinking of multiple display cells.

[0010] A visual field range determination device according to one embodiment of the present invention includes a display, a display control unit, an electroencephalograph, a time axis correlation coefficient calculation unit, and a determination unit. The display has a display screen configured with a plurality of display cells arranged two-dimensionally. The display control unit controls the light emission of the display screen. The electroencephalograph measures the electroencephalogram signal of the subject generated by the visual stimulus of light emission. The time axis correlation coefficient calculation unit calculates a correlation coefficient between the electroencephalogram signal and an expected time signal that serves as a basis for determining the visual field. The determination unit determines the visual field range of the subject.

[0011] The display control unit causes a first display cell among the plurality of display cells to blink at a first blinking frequency, and causes a second display cell different from the first display cell to blink at a second blinking frequency different from the first blinking frequency. The time axis correlation coefficient calculation unit calculates a correlation coefficient for each light emission pattern for visual field determination among the plurality of display cells. The determination unit determines the visual field range of the subject based on the correlation coefficient and the electroencephalogram signal.

[0012] In this configuration, the visual field range is determined based on a time-axis waveform including frequency components of electroencephalogram signals that are potentially generated in response to blinking visual stimuli. At this time, since the blinking frequencies of at least consecutive display cells are different, the waveforms of the electroencephalogram signals corresponding to these are also different, and these can be distinguished with high accuracy. Therefore, it is possible to accurately distinguish whether the subject was able to visually recognize the blinking of multiple display cells.

[0013] According to this invention, the visual field can be measured with higher accuracy.

[0014] FIG. 1 is a diagram showing an example of the physical configuration of a visual field range determination device according to a first embodiment. FIG. 2 is a diagram showing an example of functional blocks of the visual field range determination device according to the first embodiment. FIG. 3 is a diagram showing an example in which a plurality of display cells are assigned to a display screen. FIGS. 4A, 4B, and 4C are diagrams showing examples of blinking light emission patterns. FIG. 5 is a flowchart showing an example of a visual field range determination method according to the first embodiment. FIG. 6 is a flowchart showing an example of more specific processing of step S40 shown in FIG. 5. FIG. 7 is a flowchart showing another example of a visual field range determination method according to the first embodiment. FIG. 8 is a diagram showing an example of functional blocks of a visual field range determination device according to a second embodiment. FIG. 9 is a flowchart showing an example of a visual field range determination method according to the second embodiment. FIG. 10 is a flowchart showing another example of a visual field range determination method according to the second embodiment. FIG. 11 is a diagram showing an example of functional blocks of a visual field range determination device according to a third embodiment. FIG. 12 is a flowchart showing an example of a first visual field determination method performed by a processing device according to the third embodiment. FIG. 13 is a flowchart showing an example of a second visual field determination method performed by a processing device according to the third embodiment. Fig. 14 is a diagram showing an example of a concept for setting an area in a visual field range determination method according to a fourth embodiment. Figs. 15(A) and 15(B) are flowcharts showing an example of a visual field range determination method according to the fourth embodiment. Figs. 16(A), 16(B), and 16(C) are diagrams showing an example of a blinking switching pattern according to a fifth embodiment. Figs. 17(A) and 17(B) are diagrams showing an example of a blinking switching pattern in a visual field range determination method according to a sixth embodiment. Figs. 18(A) and 18(B) are diagrams showing an example of the structure of a visual field range determination device according to a seventh embodiment. Fig. 19 is a diagram showing an example of the structure of a visual field range determination device according to an eighth embodiment.

[0015] First Embodiment A visual field range determination device according to a first embodiment of the present invention will be described with reference to the drawings.

[0016] (Physical Configuration) FIG. 1 is a diagram showing an example of the physical configuration of a visual field range determination device according to the first embodiment.

[0017] As shown in FIG. 1, the visual field range determination device 10 includes a processing unit 20, a display 30, and an electroencephalograph 40.

[0018] The arithmetic processing device 20 is configured, for example, by a personal computer. The arithmetic processing device 20 is placed, for example, near the subject or the display device 30. The arithmetic processing device 20 may be configured, for example, by a cloud server connected via a network, or a portable information communication terminal such as a smartphone. In this case, the arithmetic processing device 20 is not limited to being placed near the subject or the display device 30, and may be placed remotely.

[0019] The display 30 is configured, for example, by a liquid crystal display. The display 30 has a display screen 300. The display 30 is positioned so that the display screen 300 is within the visual field of the subject. In this case, it is preferable that the display 30 is positioned so that the visual field and the display screen 300 are substantially the same.

[0020] The electroencephalograph 40 includes an electroencephalogram sensor and is attached to the head of the subject HM using a headband or the like.

[0021] The arithmetic processing device 20 and the display device 30 are connected in a wired manner, for example, via a communication cable. The arithmetic processing device 20 and the electroencephalograph 40 are connected in a wired manner, for example, via a communication cable. Note that communication between the arithmetic processing device 20 and the display device 30 and communication between the arithmetic processing device 20 and the electroencephalograph 40 may be wireless.

[0022] (Functional Configuration) Fig. 2 is a diagram showing an example of functional blocks of the visual field range determination device according to the first embodiment. As shown in Fig. 2, the visual field range determination device 10 includes a processing unit 20, a display 30, and an electroencephalograph 40.

[0023] The configuration of the display device 30 will be described. Fig. 3 is a diagram showing an example in which a plurality of display cells are assigned to a display screen. As shown in Fig. 3, the display screen 300 is composed of a plurality of display cells S arranged two-dimensionally. For example, in the case of Fig. 3, the display screen 300 is composed of display cells S in 15 rows and 20 columns.

[0024] Each of the plurality of display cells S is assigned an identification ID and position coordinates on the display screen 300. In the case of FIG. 3 , the upper left corner is display cell S(0,0), the lower left corner is display cell S(14,0), the upper right corner is display cell S(0,19), and the lower right corner is display cell S(14,19). For display cells S(m,n), m becomes a larger integer from top to bottom on the display screen 300, and n becomes a larger integer from left to right. This definition is an example, and is not limited to this as long as the plurality of display cells S can be individually identified. Furthermore, the number of display cells S constituting the display screen 300 is not limited to the example of FIG. 3 .

[0025] The arithmetic processing device 20 includes a display control unit 21, a signal processing unit 22, a frequency component detection unit 23, and a determination unit 24. The signal processing unit 22 includes an amplifier 221 and a filter 222.

[0026] The display control unit 21 sets a light emitting pattern for determining the visual field. The light emitting pattern for determining the visual field sets the blinking order, blinking duration, and blinking frequency of the plurality of display cells S.

[0027] The display control unit 21 sets the light emitting pattern for determining the visual field so that all display cells S are randomly selected and flash. The display control unit 21 sets different flashing frequencies for at least display cells S that flash consecutively among the plurality of display cells S. In other words, when flashing a first display cell and then a second display cell among the plurality of display cells in this order, the display control unit 21 causes the first display cell to flash at a first flashing frequency. Then, the display control unit 21 causes the second display cell, which is different from the first display cell, to flash at a second flashing frequency that is different from the first flashing frequency.

[0028] The blinking frequency is preferably, for example, 1 Hz to 50 Hz, and more preferably 10 Hz to 40 Hz. The lighting color is preferably colorless (a light color that appears white on the black display screen 300). The blinking duration of the blinking patterns PT of all display cells S is the same, and the time between adjacent blinking patterns PT (blinking interval time) is also the same.

[0029] 4A, 4B, and 4C are diagrams showing examples of blinking light emission patterns. Fig. 4A shows time T1, Fig. 4B shows time T2, and Fig. 4C shows time T3. Times T1, T2, and T3 are arranged in order with a predetermined time interval between each other.

[0030] As shown in Figures 4(A), 4(B), and 4(C), blinking pattern PT1 is set at time T1, blinking pattern PT2 is set at time T2, and blinking pattern PT3 is set at time T3.

[0031] The blinking pattern PT1 causes the display cell S(6,16) to blink at a blinking frequency F1. The blinking pattern PT2 causes the display cell S(12,3) to blink at a blinking frequency F2. The blinking pattern PT3 causes the display cell S(3,5) to blink at a blinking frequency F3.

[0032] The blinking frequency F1 is different from the blinking frequency F2. The blinking frequency F2 is different from the blinking frequency F3. The frequency difference between adjacent blinks on the time axis is preferably 2 Hz or more.

[0033] Note that the blinking frequencies (blinking frequencies) that are not adjacent on the time axis may be the same, but are preferably different within the frequency band that the blinking frequencies can take. For example, in the cases of Figures 4(A), 4(B), and 4(C), the blinking frequencies F1 and F3 may be the same, but are preferably different.

[0034] The display control unit 21 controls the light emission of the display screen based on the light emission pattern for determining the view field, thereby changing the display pattern of the display screen 300, for example, to transition from Fig. 4(A) to Fig. 4(B) to Fig. 4(C) in that order.

[0035] The display control unit 21 outputs the blinking timing and blinking frequency of the plurality of display cells S set in the light emitting pattern for visual field determination to the determination unit 24 .

[0036] When the display screen 300 of the display device 30 flashes in accordance with the light-emitting pattern for determining the field of view, if the subject HM can see the flashing, brain waves with strong frequency components corresponding to the frequency of the flashing (flashing frequency F) are generated.

[0037] As a specific example of an electroencephalogram, a steady state visual evoked potential (SSVEP (Steady State Visual Evoked Potential)) is used. The steady state visual evoked potential is an electroencephalogram signal that is synchronized with a specific visual stimulus, and for example, when a visual stimulus of frequency F is received, a frequency component of frequency F is strongly generated as an electroencephalogram signal. The electroencephalogram signal of the steady state visual evoked potential is a continuous wave with a waveform that is continuous on the time axis.

[0038] SSVEP is an electroencephalogram (EEG) signal generated in response to a stimulus signal (having a constant frequency). On the other hand, for example, visual evoked potentials (VEP) are EEG signals whose amplitude changes in response to a momentary flashing stimulus. Therefore, SSVEP is easier to detect and distinguish than EEG signals such as VEPs, whose amplitude changes instantaneously and whose frequency is difficult to detect. Furthermore, the visual field range determination device 10 uses visual stimuli that flash at a predetermined frequency. Therefore, using SSVEP allows for more reliable and accurate detection of visual responses. The electroencephalograph 40 continuously measures EEGs and outputs an EEG signal (e.g., an electrical signal based on a steady-state visual evoked potential) consisting of an electrical signal corresponding to the measurement results.

[0039] Specifically, if the subject HM can see the blinking, the electroencephalograph 40 outputs an electroencephalogram signal having a high frequency component (signal level) corresponding to the frequency of the blinking (blinking frequency F).

[0040] On the other hand, if the subject HM does not see the blinking, the electroencephalograph 40 outputs an electroencephalogram signal that has almost no or low frequency components (signal level) corresponding to the frequency of the blinking (blinking frequency F).

[0041] The electroencephalograph 40 outputs an electroencephalogram signal to the signal processing unit 22 of the arithmetic processing device 20 .

[0042] An amplifier 221 in the signal processing unit 22 amplifies the EEG signal. A filter 222 in the signal processing unit 22 suppresses noise contained in the amplified EEG signal. The signal processing unit 22 outputs the amplified and filtered EEG signal to the frequency component detection unit 23. The signal processing unit 22 can be omitted, but since EEG signals are usually weak signals, it is preferable not to omit it.

[0043] The order in which the amplifier 221 and the filter 222 are connected is not limited to this. That is, the filter 222 may be connected to the input side of the amplifier 221. The amplifier 221 may also be provided in the electroencephalograph 40.

[0044] The frequency component detection unit 23 detects the frequency components of the EEG signal. For example, the frequency component detection unit 23 performs FFT processing on the time waveform EEG signal to detect the frequency components of the EEG signal. The frequency component detection unit 23 outputs the detection result of the frequency components of the EEG signal, for example, frequency spectrum data of the EEG signal, to the determination unit 24.

[0045] The determination unit 24 determines the visual field range of the subject based on the light emitting pattern for visual field determination input from the display control unit 21 and the frequency spectrum data (frequency components) of the electroencephalogram signal.

[0046] Specifically, the determination unit 24 acquires the frequency spectrum of the electroencephalogram signal at the detection timing corresponding to the blinking timing of the plurality of display cells S set in the light emitting pattern for visual field determination. The determination unit 24 measures the blinking frequency component in the acquired frequency spectrum.

[0047] If the measured flickering frequency component is at a level equal to or greater than the determination threshold, the determination unit 24 determines that the subject can see the flickering of the display cell S corresponding to the acquired frequency spectrum (normal). On the other hand, if the measured flickering frequency component is at a level less than the determination threshold, the determination unit 24 determines that the subject cannot see the flickering of the display cell S corresponding to the acquired frequency spectrum (abnormal).

[0048] The determination unit 24 performs this determination for each of the plurality of display cells S. The plurality of display cells S are distributed across the entire display screen 300 (the range of the subject's visual field). The determination unit 24 knows in advance the position coordinates of the plurality of display cells S on the display screen 300.

[0049] The determination unit 24 creates a distribution of the determination results on the display screen 300 from the determination results (determination results for each position) of the multiple display cells S. In this way, the determination unit 24 determines the positions within the visual field range that the subject can see and the positions that the subject cannot see.

[0050] This allows the visual field range determination device 10 to determine the visual field range of the subject. At this time, by using the electroencephalogram signal, the visual field range determination device 10 can automatically determine the visual field range without requiring any operation (such as pressing a button) by the subject.

[0051] Furthermore, the visual field range determination device 10 can distinguish between determinations for adjacent display cells on the time axis by varying the blinking frequency of adjacent blinks on the time axis. Therefore, the visual field range determination device 10 can suppress erroneous determination of the visual field range.

[0052] The visual field range determination device 10 can improve the accuracy of visual field tests by suppressing erroneous determination of the visual field range. By improving the accuracy of visual field tests, the visual field range determination device 10 can lead to early detection of eye diseases. Furthermore, by improving the accuracy of visual field tests, the visual field range determination device 10 can reduce the number of visual field tests, shorten the test time, and improve usability.

[0053] In the above description, an example has been shown in which all of the display cells S on the display screen 300 are blinked at the same number of times. However, if a specific disease or the like is known, the blinking pattern may be adjusted depending on the disease. For example, the blinking pattern may be adjusted so that more blinking occurs at a specific position in the field of view depending on the disease.

[0054] (Field of View Range Determination Method 1-1) Fig. 5 is a flowchart showing an example of a field of view range determination method according to the first embodiment. Fig. 6 is a flowchart showing an example of more specific processing of step S40 shown in Fig. 5. Note that for specific explanations of each process in the flowcharts of Figs. 5 and 6, the explanation of the configurations described above can be referred to, and only the parts that require additional information will be described below.

[0055] 5, the display control unit 21 controls the illumination of a plurality of display cells S on the display screen 300 of the display device 30 based on the illumination pattern for visual field determination (S10). The electroencephalograph 40 measures electroencephalogram signals (S20). This process is repeated until the display control unit 21 causes all display cells S to blink and the electroencephalograph 40 measures electroencephalogram signals (S29: NO).

[0056] When the display control unit 21 causes all display cells S to blink and the electroencephalograph 40 measures the electroencephalogram signal (S29: YES), the frequency component detection unit 23 detects the frequency components of the electroencephalogram signal so as to include at least the blinking timing of each display cell S (S30).

[0057] The determination unit 24 determines the visual field range based on the light emitting pattern for visual field determination and the frequency components of the electroencephalogram signal (S40). More specifically, the determination unit 24 performs the process shown in FIG.

[0058] The determination unit 24 acquires the position coordinates, blinking timing, and blinking frequency of each display cell S from the light emitting pattern for visual field determination (S401). The determination unit 24 compares the blinking frequency at the blinking timing of each display cell with the frequency component of the electroencephalogram signal (S402).

[0059] If there is a frequency component with a level equal to or higher than the determination threshold (S403: YES), the determination unit 24 determines that the position of the target display cell is visible (visually confirmed normal cell) (S404).If there is no frequency component with a level equal to or higher than the determination threshold (S403: NO), the determination unit 24 determines that the position of the target display cell is not visible (visually confirmed abnormal cell) (S405).

[0060] The determining unit 24 determines the field of view range from the distribution of normal cells and abnormal cells (S406).

[0061] (Field of View Range Determination Method 1-2) Fig. 7 is a flowchart showing another example of the field of view range determination method according to the first embodiment. Note that for a specific explanation of each process in the flowchart of Fig. 7, the explanation of the configuration described above can be referred to, and only the parts that require additional information will be described below.

[0062] 7, the display control unit 21 controls the light emission of the display cells S on the display screen 300 of the display device 30 based on the light emission pattern for determining the visual field (S10A). The electroencephalograph 40 measures an electroencephalogram signal (S20A).

[0063] The frequency component detection unit 23 detects frequency components of the electroencephalogram signal so as to include at least the blinking timing of the display cell S (S30A).

[0064] The determination unit 24 determines the visual field range based on the light emitting pattern for visual field determination and the frequency components of the electroencephalogram signal (S40A).

[0065] The visual field range determination device 10 (display control unit 21 (display 30), electroencephalograph 40, frequency component detection unit 23, and determination unit 24) repeats this process until determination of all display cells S is completed (S29A: NO). When determination of all display cells S is completed (S29: YES), the visual field range determination device 10 ends the visual field determination.

[0066] [Second Embodiment] A visual field range determination device according to a second embodiment of the present invention will be described with reference to the drawings. Fig. 8 is a diagram showing an example of functional blocks of the visual field range determination device according to the second embodiment.

[0067] 8, the visual field range determination device 10A according to the second embodiment differs from the visual field range determination device 10 according to the first embodiment in that the frequency component detection unit 23 is replaced with a time axis correlation coefficient calculation unit 23A, and in the method of visual field determination in a determination unit 24A. The other configurations and processes of the visual field range determination device 10A are the same as those of the visual field range determination device 10, and descriptions of similar parts will be omitted.

[0068] The visual field range determination device 10A includes a processing device 20A, a display 30, and an electroencephalograph 40. The processing device 20A includes a display control unit 21, a signal processing unit 22, a time axis correlation coefficient calculation unit 23A, and a determination unit 24.

[0069] The time axis correlation coefficient calculation unit 23A stores multiple expected time signals that are likely to be waveforms of EEG signals of a predetermined time length that include the timing of blinking. Specifically, when visual recognition is possible, an EEG signal of a time axis that includes a blinking frequency component on the frequency axis is obtained. Such an EEG signal of a time axis that includes a blinking frequency component on the frequency axis is stored as an expected time signal. In this way, the multiple expected time signals are signals of a time axis that include a frequency component of the blinking frequency, and therefore serve as a reference for visual field determination.

[0070] The time axis correlation coefficient calculation unit 23A calculates a correlation coefficient using the waveform of the acquired electroencephalogram signal and the expected time signal.

[0071] The determining unit 24A determines whether the subject is seeing the flickering (normal) or not (abnormal) based on the magnitude of the correlation coefficient.

[0072] For example, the time axis correlation coefficient calculation unit 23A sets waveform pattern 1 as the expected time signal for the first blink. The time axis correlation coefficient calculation unit 23A sets waveform pattern 2 as the expected time signal for the second blink, which is different from the first blink. The time axis correlation coefficient calculation unit 23A calculates the correlation coefficient between waveform pattern 1 and waveform pattern 2 for the waveform of the electroencephalogram signal acquired in response to the first blink signal.

[0073] If the correlation coefficient is "Pattern 2<Pattern 1", the judgment unit 24A judges that the subject sees Pattern 1 correctly (normal). If the correlation coefficient is "Pattern 1≦Pattern 2", the judgment unit 24A judges that the subject does not see Pattern 1 correctly (abnormal).

[0074] In this way, visual field range assessment device 10A can assess the visual field range based on the time-axis electroencephalogram signal without detecting frequency components of the electroencephalogram signal. Furthermore, with this configuration, visual field range assessment device 10A does not use an absolute threshold, which can reduce errors due to differences in how people see things.

[0075] (Field of View Range Determination Method 2-1) Fig. 9 is a flowchart showing an example of a field of view range determination method according to embodiment 2. Note that for specific explanations of each process in the flowchart of Fig. 9, the explanation of the configuration described above can be referred to, and only the parts that require additional explanation will be described below.

[0076] 9, the display control unit 21 controls the illumination of a plurality of display cells S on the display screen 300 of the display device 30 based on the illumination pattern for visual field determination (S10). The electroencephalograph 40 measures electroencephalogram signals (S20). This process is repeated until the display control unit 21 causes all display cells S to blink and the electroencephalograph 40 measures electroencephalogram signals (S29: NO).

[0077] When the display control unit 21 blinks all display cells S and the EEG meter 40 measures the EEG signal (S29: YES), the time axis correlation coefficient calculation unit 23A calculates the correlation coefficient between the EEG signal and the expected time signal at the blinking timing of each display cell (S30t).

[0078] The determination unit 24A determines the field of view range based on the correlation coefficient (S40t).

[0079] (Field of View Range Determination Method 2-2) Fig. 10 is a flowchart showing another example of a field of view range determination method according to the second embodiment. Note that for specific explanations of each process in the flowchart of Fig. 10, the explanation of the configuration described above can be referred to, and only the parts that require additional explanation will be described below.

[0080] 10, the display control unit 21 controls the light emission of the display cells S on the display screen 300 of the display device 30 based on the light emission pattern for determining the visual field (S10A). The electroencephalograph 40 measures an electroencephalogram signal (S20A).

[0081] The time axis correlation coefficient calculation unit 23A calculates the correlation coefficient between the electroencephalogram signal and the expected time signal at the timing of blinking of the display cell (S30tA).

[0082] The determination unit 24A determines the field of view range based on the correlation coefficient (S40tA).

[0083] The visual field range determination device 10A (display control unit 21 (display 30), electroencephalograph 40, time axis correlation coefficient calculation unit 23A, and determination unit 24A) repeats this process until determination of all display cells S is completed (S29A: NO). When determination of all display cells S is completed (S29: YES), the visual field range determination device 10A ends the visual field determination.

[0084] [Third Embodiment] A visual field range determination device according to a third embodiment of the present invention will be described with reference to the drawings. Fig. 11 is a diagram showing an example of functional blocks of the visual field range determination device according to the third embodiment. As shown in Fig. 11, the visual field range determination device 10B according to the third embodiment differs from the visual field range determination device 10 according to the first embodiment in that it includes a storage unit 25 and in part of the method of visual field determination. The other configurations and processes of the visual field range determination device 10B are the same as those of the visual field range determination device 10, and descriptions of similar parts will be omitted.

[0085] The visual field range determination device 10B includes a processing device 20B. The processing device 20B includes a storage unit 25 in addition to the configuration of the processing device 20. The storage unit 25 is configured by a storage medium such as an HDD or SSD.

[0086] The storage unit 25 stores the result of the determination of the visual field range output from the determination unit 24 .

[0087] In this configuration, the processor 20B adjusts the light emitting pattern for determining the field of view based on the determination result of the field of view range. Specifically, the following process is performed.

[0088] (A) Process for re-determination when there is a visually abnormal cell in the current determination result of the visual field range Fig. 12 is a flowchart showing an example of the first visual field determination method performed by the arithmetic processing device according to the third embodiment. Steps S10, S20, S29, S30, and S40 in Fig. 12 according to the third embodiment are the same as steps S10, S20, S29, S30, and S40 in Fig. 5 according to the first embodiment, and description of these processes will be omitted.

[0089] The display control unit 21 acquires the current judgment result of the field of view range stored in the storage unit 25. The display control unit 21 detects whether or not there is a visually abnormal cell in the judgment result of the current field of view range. If the display control unit 21 detects that there is a visually abnormal cell (S50: YES), it adjusts the light emitting pattern for field of view judgment so that the visually abnormal cell flashes again.

[0090] Specifically, for example, in a re-inspection, only the visually abnormal cells are flashed again. Alternatively, for example, in a re-inspection, only the area around the visually abnormal cells is flashed again, including the visually abnormal cells. Alternatively, for example, in an area around the visually abnormal cells, including the visually abnormal cells, the area is flashed with high position resolution, and in an area far from the visually abnormal cells, the area is flashed with low resolution.

[0091] The determination unit 24 determines the visual field range based on the adjusted light emission pattern for visual field determination and the frequency components of the electroencephalogram signal reacting thereto (S61). Then, the determination unit 24 updates the determination result of the visual field determination (S62).

[0092] Such a configuration and processing can further reduce erroneous determination of visually abnormal cells.

[0093] In the above description, the display control unit 21 acquires the visual field range determination result stored in the storage unit 25, but it is also possible to directly input information about visually abnormal cells from the determination unit 24 to the display control unit 21. In this case, the display control unit 21 can, for example, interrupt the currently executed light-emitting pattern for visual field determination with a process for re-flashing the visually abnormal cells.

[0094] (B) Visual Field Range Determination Process Based on Past Visual Field Range Determination Results FIG. 13 is a flowchart showing an example of a second visual field determination method performed by the arithmetic processing device according to the third embodiment.

[0095] The display control unit 21 acquires past visual field range determination results stored in the storage unit 25 (S71). Past visual field range determination results include, for example, the previous visual field range determination result, the visual field range determination result before that, and the visual field range determination results of multiple past visual field range determinations.

[0096] If a visually abnormal cell is present in the visual field range measurement results (S72: YES), the display control unit 21 sets a visual field determination light-emitting pattern in which a detailed determination area including the visually abnormal cell is set as the visual field determination light-emitting pattern for determining the current visual field range. The detailed determination area is an area in which blinking is set with higher positional resolution than other areas. The determination unit 24 determines the visual field range based on the visual field determination light-emitting pattern in which the detailed determination area is set and the frequency components of the electroencephalogram signal reacting to it (S74).

[0097] If there are no visually abnormal cells in the visual field range measurement results (S72: NO), the display control unit 21 uses the default visual field determination light-emitting pattern. The default visual field determination light-emitting pattern is a visual field determination light-emitting pattern that has a constant positional resolution across the entire display screen 300, and corresponds to the visual field determination light-emitting pattern shown in the first embodiment. The determination unit 24 determines the visual field range based on the default visual field determination light-emitting pattern and the frequency components of the electroencephalogram signal that reacts to it (S73).

[0098] With this configuration and processing, the arithmetic processing device 20B can refer to past judgment results of the field of view range, and if there was a visually abnormal cell in the past, it can focus on the position and surrounding area to judge the field of view range. If there was no visually abnormal cell in the past, the arithmetic processing device 20B can uniformly judge the entire field of view range.

[0099] [Fourth embodiment] A visual field range determination device according to a fourth embodiment of the present invention will be described with reference to the drawings. The functional configuration of the visual field range determination device according to the fourth embodiment is the same as that of the visual field range determination device according to the third embodiment, and therefore a description thereof will be omitted.

[0100] Fig. 14 is a diagram showing an example of a concept of setting areas in the visual field range determination method according to the fourth embodiment. Fig. 15(A) and Fig. 15(B) are flowcharts showing an example of the visual field range determination method according to the fourth embodiment.

[0101] 14, the display control unit 21 sets a plurality of first regions RE on the display screen 300, each including a plurality of display cells S. The plurality of first regions RE are set so as to be distributed over the entire display screen 300. The sizes (areas) of the plurality of first regions RE are the same, but may be different. The display control unit 21 sets representative display cells SR in the plurality of first regions.

[0102] (Field of View Range Determination Method α) As shown in FIG. 15A, the arithmetic processing device determines the field of view range using representative positions of a plurality of first regions (S81).

[0103] More specifically, the display control unit 21 sets the light emitting pattern for visual field determination so as to sequentially blink the representative display cells SR of the plurality of first regions RE. The determination unit 24 determines the visual field range in the first stage based on the light emitting pattern for visual field determination using the first regions RE and the frequency components of the electroencephalogram signal reacting to the light emitting pattern.

[0104] The method of determining the visual field range is the same as in the first and second embodiments, and the blinking order of the representative display cell SR in the first region is random. The region where it is determined that the subject cannot see the representative display cell SR (when the representative display cell is the abnormal display cell) is determined to be an abnormal region, and the region where it is determined that the subject can see the representative display cell SR is determined to be a normal region.

[0105] If there is an abnormal region (S82: YES), the arithmetic processing unit determines the field of view range of the abnormal region in display cell units (S83A).

[0106] More specifically, the display control unit 21 acquires the result of the determination of the field of view range in the first stage. If an abnormal area is present in the result of the determination of the field of view range in the first stage, the display control unit 21 sets a light emitting pattern for determining the field of view so that all display cells in the abnormal area are randomly selected and flashed in units of display cell S.

[0107] The determination unit 24 performs a second stage determination of the visual field range based on this light emitting pattern for visual field determination and the frequency components of the electroencephalogram signal in response thereto.

[0108] By this process, the arithmetic processing device can roughly determine the entire visual field, and then determine in more detail the partial areas where there is a high possibility of visual abnormality. As a result, for example, the arithmetic processing device can reduce the total time required to determine the visual field range while suppressing a decrease in the accuracy of the determination of the visual field range.

[0109] (Field of View Range Determination Method β) As shown in FIG. 15B, the arithmetic processing device determines the field of view range using representative positions of a plurality of first regions (S81).

[0110] If there is an abnormal region (S82: YES), the arithmetic processing unit increases the blinking frequency of the display cells in the abnormal region and determines the visual field range (S83B).

[0111] Steps S81 and S82 in FIG. 15B are the same as those in FIG. 11A, and a description thereof will be omitted.

[0112] More specifically, in step S83B, the display control unit 21 acquires the determination result of the field of view range in the first stage.

[0113] If an abnormal region is present in the visual field range determination result in the first stage, the display control unit 21 increases the blinking frequency of the display cells S in the abnormal region compared to the blinking frequency of the display cells S in other regions (normal regions). Then, the display control unit 21 sets a light-emitting pattern for visual field determination so that all display cells are randomly selected and blink. The determination unit 24 performs a second-stage visual field range determination based on this light-emitting pattern for visual field determination and the frequency components of the electroencephalogram signal reacting to it.

[0114] By this process, the arithmetic processing device can roughly determine the entire visual field, and then determine in more detail the partial areas that are likely to have visual abnormalities. Furthermore, the arithmetic processing device can measure the visual field range on a display cell-by-cell basis for areas other than the abnormal area.

[0115] [Fifth Embodiment] A visual field range determination device according to a fifth embodiment of the present invention will be described with reference to the drawings. The functional configuration of the visual field range determination device according to the fifth embodiment is the same as that of the visual field range determination device according to the first embodiment, and therefore a description thereof will be omitted.

[0116] 16A, 16B, and 16C are diagrams showing examples of blinking switching patterns according to the fourth embodiment.

[0117] As shown in Figures 16(A), 16(B), and 16(C), the display control unit of the processing unit changes the blinking interval time, in other words, the blinking switching speed, as the light-emitting pattern for determining the field of view range.

[0118] 16(A), 16(B), and 16(C), blinking interval time TC12 is the time from the end of blinking pattern PT1 to the start of blinking pattern PT2. Blinking interval time TC23 is the time from the end of blinking pattern PT2 to the start of blinking pattern PT3. Blinking interval time TC34 is the time from the end of blinking pattern PT3 to the start of blinking pattern PT4.

[0119] 16A, the blinking interval time gradually becomes shorter, in other words, the blinking switching speed gradually becomes faster.

[0120] In the case of Fig. 16(B), the blinking interval time gradually becomes longer, in other words, the blinking switching speed gradually becomes slower.

[0121] In the case of Fig. 16(C), the blinking interval time is random, in other words, the blinking switching speed is random.

[0122] With this configuration, the visual field range determination device can measure the visual field range, as well as train dynamic visual acuity and contract / relax muscles required for vision.

[0123] [Sixth embodiment] A visual field range determination device according to a sixth embodiment of the present invention will be described with reference to the drawings. The functional configuration of the visual field range determination device according to the sixth embodiment is the same as that of the visual field range determination device according to the first embodiment, and therefore a description thereof will be omitted.

[0124] 17A and 17B are diagrams showing an example of a blinking switching pattern in the visual field range determination method according to the fifth embodiment. Fig. 17A shows a blinking state for a plurality of periods in one diagram.

[0125] 17A, the blinking pattern PT1A at time T1 is located near the left edge of the display screen 300 and has a blinking frequency F1. The blinking pattern PT2A at time T2, which follows time T1, is located near the right edge of the display screen 300 and has a blinking frequency F2.

[0126] By using such a blinking pattern, the subject sees the light moving in the horizontal direction, which can be used to train, for example, DVA dynamic visual acuity. Note that when the focus is primarily on training dynamic visual acuity, the blinking frequency of blinking pattern PT1A and the blinking frequency of blinking pattern PT2A may be the same.

[0127] 17B, ​​the blinking pattern PT1B at time T1 is a blinking pattern with a small diameter and a blinking frequency of F1. The blinking pattern PT2B at time T2 following time T1 is located near the right edge of the display screen 300 and has a blinking frequency of F2.

[0128] By using such a blinking pattern, the subject will see blinking of different sizes, which can be used to train, for example, KVA dynamic visual acuity. Note that when training dynamic visual acuity is the main focus, the blinking frequency of blinking pattern PT1B and the blinking frequency of blinking pattern PT2B may be the same.

[0129] [Seventh embodiment] A visual field range determination device according to a seventh embodiment of the present invention will be described with reference to the drawings. The functional configuration of the visual field range determination device according to the seventh embodiment is the same as that of the visual field range determination device according to the first embodiment, and therefore a description thereof will be omitted.

[0130] 18A and 18B are diagrams showing an example of the structure of a visual field range determination device according to the seventh embodiment.

[0131] 18A, the visual field range determination device 10G according to the seventh embodiment is a pair of goggles worn by the subject HM. The above-described arithmetic processing device 20, display device 30, and electroencephalograph 40 are integrally provided in the goggle-type visual field range determination device 10G.

[0132] 18B, the visual field range determination device 10S according to the seventh embodiment is a pair of smart glasses worn by the subject HM. The above-described arithmetic processing device 20, display device 30, and electroencephalograph 40 are integrally provided in the smart glasses-type visual field range determination device 10S.

[0133] In this way, visual field range determination device 10G and visual field range determination device 10S are wearable by subject HM, so the devices can be made smaller and restrictions on the location where the visual field range can be measured can be alleviated.

[0134] [Eighth embodiment] A visual field range determination device according to an eighth embodiment of the present invention will be described with reference to the drawings. The functional configuration of the visual field range determination device according to the eighth embodiment is the same as that of the visual field range determination device according to the first embodiment, and therefore a description thereof will be omitted.

[0135] FIG. 19 is a diagram showing an example of the structure of a visual field range determination device according to the eighth embodiment.

[0136] 19, the visual field range determination device 10I according to the eighth embodiment is a stationary device. The above-described arithmetic processing device 20, display device 30, and electroencephalograph 40 are integrally provided in the stationary type visual field range determination device 10I. The visual field range determination device 10I includes a cylinder through which the subject HM looks, and an electroencephalogram sensor is installed at the open end of the cylinder.

[0137] With this configuration, the visual field range can be measured without the subject HM having to wear an electroencephalograph.

[0138] The above-described embodiments can be combined as needed, and effects according to each combination can be achieved.

[0139] In the above explanation, one display cell S is blinked at one blinking timing, but it is also possible to blink a plurality of display cells S with different blinking frequencies. In this case, for example, it is also possible to make the blinking times overlap.

[0140] Furthermore, in the above description, an embodiment using only white light has been shown, but other colors may also be used, and multiple colors may also be used.

[0141] T1, T2, T3: time TC12, TC23, TC34: blinking interval time 10, 10A, 10B, 10G, 10I, 10S: visual field range determination device 20, 20A, 20B: arithmetic processing device 21: display control unit 22: signal processing unit 23: frequency component detection unit 23A: time axis correlation coefficient calculation unit 24, 24A: determination unit 25: memory unit 30: display unit 40: electroencephalograph 221: amplifier 222: filter 300: display screen F1, F2, F3: blinking frequency HM: subject PT1, PT1A, PT1B, PT2, PT2A, PT2B, PT3, PT4: blinking pattern RE: first region S: display cell SR: representative display cell

Claims

1. A visual field range determination device comprising: a display having a display screen composed of a plurality of display cells arranged two-dimensionally; a display control unit that controls the light emission of said display screen; an electroencephalograph that measures the electroencephalogram (EEG) signal of a subject generated by visual stimulation caused by light emission; a frequency component detection unit that detects the frequency components of said EEG signal; and a determination unit that determines the visual field range of said subject, wherein said display control unit causes a first display cell of said plurality of display cells to blink at a first blinking frequency and causes a second display cell different from said first display cell to blink at a second blinking frequency different from said first blinking frequency, and said determination unit determines the visual field range of said subject from the blinking frequency of the light emission pattern for visual field determination of said plurality of display cells and the frequency components of said EEG signal.

2. The visual field range determination device of claim 1, wherein the determination unit determines that the subject's visual recognition of the first display cell is normal if the first flickering frequency among the frequency components of the electroencephalogram signal of the subject is at a level equal to or higher than a determination threshold, determines that the subject's visual recognition of the first display cell is abnormal if the first flickering frequency among the frequency components of the electroencephalogram signal of the subject is at a level below the determination threshold, and determines the range of the plurality of display cells determined to be normal as the visual field range of the subject.

3. A visual field range determination device comprising: a display having a display screen composed of a plurality of display cells arranged two-dimensionally; a display control unit that controls the light emission of said display screen; an electroencephalograph that measures the electroencephalogram signal of a subject generated by visual stimulation by light emission; a time axis correlation coefficient calculation unit that calculates a correlation coefficient between an expected time signal that serves as a reference for visual field determination and said electroencephalogram signal; and a determination unit that determines the visual field range of said subject, wherein said display control unit causes a first display cell of said plurality of display cells to blink at a first blinking frequency, and causes a second display cell different from said first display cell to blink at a second blinking frequency different from said first blinking frequency, said time axis correlation coefficient calculation unit calculates a correlation coefficient for each light emission pattern for visual field determination in said plurality of display cells, and said determination unit determines the visual field range of said subject based on said correlation coefficient and said electroencephalogram signal.

4. A visual field range determination device according to any one of claims 1 to 3, wherein the display control unit sets the light emitting pattern for determining the visual field so that all display cells are randomly selected and flashed.

5. A visual field range determination device according to any one of claims 1 to 4, wherein the display control unit adjusts the light emitting pattern for determining the visual field based on the determination result of the visual field range.

6. The visual field range determination device according to claim 2, wherein the display control unit adjusts the light emitting pattern for determining the visual field so that, if there is a display cell determined to be abnormal based on the determination result of the visual field range, the display cell determined to be abnormal flashes again.

7. The visual field range determination device of claim 2, wherein the display control unit sets a plurality of first regions on the display screen, each containing a plurality of display cells, and causes representative display cells in the plurality of first regions to blink as the light-emitting pattern for determining the visual field, and when the representative display cell is determined to be abnormal, all display cells in the first region including the representative display cell determined to be abnormal are randomly selected and set to blink.

8. A visual field range determination device according to any one of claims 1 to 7, wherein the display control unit changes the switching speed of the blinking as the light emitting pattern for determining the visual field.

9. A visual field range determination device according to any one of claims 1 to 8, comprising a storage unit for storing the results of the visual field range determination.

10. A visual field range determination device according to any one of claims 1 to 9, wherein the electroencephalogram signal is an electrical signal based on a steady-state visual evoked potential.

11. A visual field range determination method, wherein a display control unit controls the light emission of a display screen, a display unit flashes the display screen, an electroencephalograph measures the subject's electroencephalogram signal generated by visual stimulation caused by light emission, a frequency component detection unit detects the frequency component of the electroencephalogram signal, a determination unit determines the visual field range of the subject, the display control unit flashes a first display cell of the plurality of display cells at a first flashing frequency and flashes a second display cell different from the first display cell at a second flashing frequency different from the first flashing frequency, and the determination unit determines the visual field range of the subject from the flashing frequency of the light emission pattern for visual field determination of the plurality of display cells and the frequency component of the electroencephalogram signal.

12. A visual field range determination method, in which a display control unit controls the light emission of a display screen, a display unit flashes the display screen, an electroencephalograph measures the subject's electroencephalogram signal generated by visual stimulation caused by light emission, a time axis correlation coefficient calculation unit calculates a correlation coefficient between the electroencephalogram signal and an expected time signal serving as a reference for visual field determination, and a determination unit determines the visual field range of the subject, the display control unit flashes a first display cell of the plurality of display cells at a first flashing frequency and flashes a second display cell different from the first display cell at a second flashing frequency different from the first flashing frequency, the time axis correlation coefficient calculation unit calculates a correlation coefficient for each light emission pattern for visual field determination in the plurality of display cells, and the determination unit determines the visual field range of the subject based on the correlation coefficient and the electroencephalogram signal.

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