JP2000245697A - Vision function measurement device and storage medium for visual function measurement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To objectively and automatically provide the accurate measured value of a visual function and to shorten measurement time simultaneously. SOLUTION: A graphic image display device 2 for generating/displaying a graphic image corresponding to the visual function to be inspected and an eyeball movement measurement device 10 for detecting the visual line movement of a patient are used. The level of visual stimulation presented by the graphic image display device 2 is controlled to be increased/decreased by judgment signals from the eyeball movement measurement device 10. The eyeball movement measurement device 10 obtains the presentation information of the graphic image by the graphic image display device 2, judges whether or not eyeball movement coincides with the presentation requirement corresponding to a predetermined reference and feeds back the judgment signal to the graphic image display device 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual function measuring device for automatically measuring a visual function of a subject to which a visual stimulus is given, and a program for automating the visual function measurement. The present invention relates to a stored visual function measurement storage medium.

[0002]

2. Description of the Related Art Conventionally, in the measurement of a visual function, the presence or absence of perception / recognition has been determined based on a response of a subject observing a visual stimulus. In other words, regarding the perception and recognition response to the visual stimulus level, the visual stimulus is presented to the subject at various levels and conditions,
According to the measurement task, the measurement is made by an oral answer such as “whether it is visible or not” or a subjective and conscious response such as a switch operation.

[0003]

However, the conventional measuring methods as described above rely on the subjective judgment of the subject, and therefore have the drawbacks that errors can occur and lack accuracy. Was done. Also, even if there is an intentional response that is different from the fact, it has been difficult to determine and eliminate this. Furthermore, this type of visual function measurement has a drawback that it generally requires a large amount of measurement time because it requires a visual stimulus presentation operation by an experimenter and a reaction operation of a subject.

Accordingly, an object of the present invention is to provide
A visual function measuring device capable of accurately and objectively obtaining a measured value of visual function and shortening the measurement time, and a program for automating such visual function measurement are stored. An object of the present invention is to provide a storage medium for visual function measurement.

[0005]

In order to achieve the above object, a visual function measuring apparatus according to the present invention comprises: an image display means for presenting a visual stimulus for measuring a visual function of a subject; Eye movement measuring means for detecting the eye movement of the subject gazing at the visual stimulus by the graphic display means, and presented by the graphic display means in response to a detection signal output from the eye movement measuring means. Based on level control means for controlling the level of the visual stimulus and presentation information including the presentation position and / or presentation time of the visual stimulus by the icon image display means, whether or not the eye movement of the subject satisfies predetermined requirements A visual function corresponding to each level of the visual stimulus based on the property that the visual response to the visual stimulus is specifically reflected in the eye movement of the subject. It is intended.

The storage medium for measuring visual function according to the present invention is adapted to correspond to each level of the visual stimulus based on the property that the visual response to the visual stimulus is specifically reflected in the eye movement of the subject. A storage medium storing a program for measuring the visual function of the subject, the image display step of presenting a visual stimulus for measuring the visual function of the subject, and a subject gazing at the visual stimulus. An eye movement measuring step of detecting eye movement of the subject; a level control step of controlling a level of a visual stimulus presented by the icon display step in response to a detection signal obtained by the eye movement measuring step; A determination step for determining whether or not the eye movement of the subject satisfies predetermined requirements based on presentation information including a presentation position and / or a presentation time of the visual stimulus in the step; And-up is obtained by storing in the form of readable program.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a prerequisite description for carrying out the present invention will be given.

[0008] The appearance of eyeball / eye movement differs depending on the level of perception / recognition. That is, when a certain visual stimulus is given to the eyeball of the subject, the visible result of the visual stimulus has a property of reacting specifically to the state of the eye movement, so in each of the embodiments described below, , Measures the level of the visual stimulus and the corresponding eye movement, and based on the measurement results,
A response corresponding to a predetermined visual stimulus level is determined.

For this purpose, an image display device for generating and displaying an image corresponding to the visual function to be inspected and an eye movement measuring device for detecting the gaze movement of the subject are used. The level of the visual stimulus presented by the iconic display device is controlled to increase or decrease by a determination signal from the eye movement measuring device.

On the other hand, the eye movement measuring apparatus obtains presentation condition information such as a presentation time or a presentation position of an icon image on the icon image display device, and determines whether or not the eye movement satisfies the presentation requirement by a predetermined reference. And the determination signal is fed back to the icon image display device. The icon display device uses the returned determination signal as a control signal for the level of the visual stimulus, and increases or decreases the level of the visual stimulus to be presented. The icon display device outputs the current level of the visual stimulus. Further, when the level of the visual stimulus has reached a predetermined value, it is notified that the level of the visual stimulus is a measurement value of the task.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1 In a first embodiment described here, a case of measuring the depth visual acuity of both eyes will be described with reference to FIGS.

FIG. 1 is an overall configuration diagram of a visual function measuring apparatus to which the present invention is applied. In the figure, reference numeral 2 denotes an icon display device for presenting a stereoscopic image described later to the subject, and includes a display 4 and a stereoscopic image display control device 6. Reference numeral 8 denotes an eyeball imaging camera for imaging the eyeball of the subject. Reference numeral 10 denotes an eye movement measuring device, which includes a gaze movement measuring circuit 12 and a determination circuit 14. Reference numeral 20 denotes a control circuit for controlling the icon image display device 2 and the eye movement measuring device 10 described above.
The operation of the visual function measuring device is controlled according to a control program stored in the OM (or a storage medium such as a RAM) 22.

FIG. 2 is a diagram schematically illustrating the operation in the first embodiment.

FIG. 3 is a flowchart showing a control procedure stored in the ROM 22 of FIG.

In the first embodiment, a dynamic random icon three-dimensional shape display device is used as the icon display device 2 for displaying the visual inspection icon. That is, as shown in FIG. 2, there is a random image in the form of a noise (dynamic random dot pattern: referred to as DRDP) on the entire screen, and a specific shape having binocular parallax that is a key to stereoscopic perception (here, Circle and square) and arrange them on the left and right, respectively.

In the display case 1, the binocular parallax is given so that the quadrangular shape protrudes toward the viewer, and the binocular parallax is not given to the circular shape. In the next display case 2, binocular parallax is not given to the quadrangle, but binocular parallax is given so that a circle pops out, and this is alternately repeated. As described above, in order to display a three-dimensional shape in DRDP, Japanese Patent No. 2,746,671 by the present applicant.
The technique described in Japanese Patent Publication No. 5 (image display device for binocular inspection) may be used. That is, each time the stereoscopic state changes as in the display case 1 and the display case 2, binocular parallax of a predetermined shape is given to a random image having a different pattern. In addition,
The image memory described in the above-mentioned Japanese Patent No. 2746715 can be integrated with a part of the image generating device without being particularly configured separately from the image generating device. Therefore, in the present embodiment, the ROM shown in FIG.
22 is used.

The repetition period of the display case 1 and the display case 2 is appropriately selected from 0.5 Hz to 1 Hz at which the line of sight easily moves.

It is also possible to move one shape left and right without alternately popping out two solid shapes at two positions.

An eye movement measuring circuit 12 included in the eye movement measuring apparatus 10 includes an eyeball imaging camera (TV camera) 8.
The movement of the pupil image of the subject's eyeball is detected based on the video signal output from. Then, the determination circuit 14 determines whether the subject's line of sight is directed to a three-dimensional circular or square shape. This can be easily determined by calibrating the index position and the eye movement position in the screen in advance.

The judgment signal output from the judgment circuit 14 is
It is fed back to the icon display 2 which is a dynamic random icon three-dimensional shape display. On the other hand, the stereoscopic image display control device 6 outputs time information (presentation information) representing the two shapes to the determination circuit 14.

Next, the operation of the first embodiment will be described with reference to FIG.

In the three-dimensional image display control device 6, first, the value of the binocular disparity is sequentially increased from 0 (step S1), and each of the circular shape and the square shape is alternately displayed on the near side (step S1).
2). At this time, the determination circuit 14 of the eye movement measuring device 10
Thus, a determination signal is obtained as to whether or not the line of sight always faces the three-dimensional shape that has been revealed (step S3). In FIG. 2, if the display case 1 is to the right and the display case 2 is to the left, it is “true”.

At this time, in order to avoid erroneous determination due to accidental movement of the line of sight, the determination is made in several states. At first, due to binocular parallax equal to or less than depth visual acuity, no three-dimensional shape is recognized, and the line of sight is directed regardless of the appearance of the three-dimensional shape. The determination signal at that time has a value of “false”, and at this time, the binocular parallax is slightly increased (Step S
1). Thus, the binocular parallax is sequentially increased until a three-dimensional shape is recognized. Then, the line of sight naturally turns to the expressed three-dimensional shape, and a value of “true” is obtained from the determination circuit 14. The value of the binocular disparity at this time is the binocular depth visual acuity of the subject to be obtained, which is output to the outside (step S
4).

Thereafter, the binocular parallax is further increased sequentially (step S5), and each of the circular shape and the square shape is brought forward (step S2 '). Then, the binocular parallax exceeds the fusion limit, so that stereoscopic vision can no longer be performed, and a stereoscopic shape cannot be recognized. At this time, the line of sight does not turn to the three-dimensional shape as in the beginning, and the determination signal outputs "false" (step S6). The value of the binocular parallax at this time is called a fusion limit value of the convergence motility (step S7). In this way, the range of the binocular disparity value during which the determination of the eyeball measuring device is “true” is automatically and objectively obtained as the stereoscopic region of the subject.

When the position of one icon is moved instead of two icons, the eyeball has the property of being unconsciously guided by the movement of the perceived icon. It may be determined whether or not it is done.

Second Embodiment Next, a second embodiment will be described with reference to FIGS. Here, instead of the depth binocular parallax described above, luminance and color contrast (perception of rectangular map)
Threshold, contrast spatial frequency (perception of striped pattern image) threshold,
A description will be given of a case where a perception level for a change in an element of various dimensions such as a flicker frequency (perception of an image in which uniform brightness changes on a time axis) threshold is measured.

As the icon display device (visual inspection icon display device) 2 shown in FIG. 1, a device that presents an icon image corresponding to the above problem is used. The background element of the target icon is placed in the same state as the state where the icon cannot be perceived, which does not reach or exceeds the perception threshold of the icon. Among them, specific shapes, for example, a circular shape and a square shape as shown in FIG. 2 are selected and arranged on the left and right, respectively. In the display case 1, the change of the preceding element is given in the square, and no change of the element is given in the circle. In the display case 2, the change of the element is not given in the square, and the change of the element is given in the circle. This is alternately repeated.

Here, one shape may be moved right and left without alternately changing the two shapes.

The eye movement measuring circuit 12 included in the eye movement measuring device 10 detects the movement of the pupil image of the eye taken by the eye photographing camera (TV camera) 8 as in the first embodiment. Then, the determination circuit 14 determines whether the subject's line of sight is directed to the circle or the square where the element changes. The determination signal output from the determination circuit 14 is input to the three-dimensional image display control device 6.

On the other hand, the icon image display device 2 outputs time information (presentation information) representing the two shapes to the determination circuit 14.

Next, the operation of the second embodiment will be described with reference to FIG.

Elements required for the visual function include luminance and color contrast changes that are perceived when the value of the element is increased, and spatial and frequency flicker frequencies that cannot be perceived when the element value is increased. This differs only in the direction in which the value is increased or decreased, so that the former example will be described here.

In the image display device 2 for visual inspection, first, the element changes are sequentially increased from a position lower than the perception threshold, so that a circle and a square are alternately displayed (step S).
21). At that time, the judgment circuit 14 of the eye movement measuring device 10
Thus, a determination signal is obtained as to whether or not the line of sight always faces the exposed shape (step S22). In the example of FIG. 2, the result is “true” when viewed to the right in the display case 1 and to the left in the display case 2. At first, the shape is not recognized because it is equal to or less than the threshold, and the line of sight is directed regardless of the appearance of the shape. The determination signal at that time has a value of "false", and at this time, the element change is further increased (step S21).

The elements are sequentially increased until the shape is recognized. Then, the line of sight turns to the exposed shape, and a “true” value is obtained from the eye movement measuring device. The value of the element at this time is the subject's perception threshold to be obtained, and this is output to the outside (step S23).

In this way, the boundary between the determination of "true" and "false" by the eyeball measuring device is automatically and objectively recognized as the perception threshold for the visual element.

Embodiment 3 Embodiment 3 relates to a case where the fusion limit of binocular stereopsis is measured by a method different from that of Embodiment 1, and will be described with reference to the explanatory diagram of FIG. 5 and the flowchart of FIG. I do.

If the respective images projected to the left and right eyes are slightly shifted to the left and right positions, a stereoscopic view is obtained by a function of uniting the images and viewing them. However, there is a limit at which fusion does not occur when the deviation increases, and this is called the fusion limit (width). This is an important value both for an ophthalmologic function test and for a design standard for stereoscopic images.

In this embodiment, a stereoscopic video display is used as the visual inspection icon display. This uses left and right eye images ( _AL , _AR ) to present one stereoscopic image. Then, A _L and A _R are moved at a period opposite to each other, and a binocular parallax corresponding to a longitudinal vibration having a constant depth is given. The binocular parallax variation width is slightly larger than the retinal (sensory) fusion range and is set to the value of the convergence (motor) fusion range.

The eye movement measuring apparatus uses the same apparatus 10 as in the first embodiment (see FIG. 1), and determines whether the gaze movements of the right and left eyes are opposite “true” or in-phase “false”. Is output from the determination circuit 14.

Next, the operation of the third embodiment will be described with reference to FIG.

In the image display device 2, first, the average value of the binocular parallax is set to 0, and the position of the stereoscopic image is moved back and forth (step S31). At this time, a determination signal is obtained from the determination circuit 14 of the eye movement measuring apparatus 10 as to whether the line of sight of both eyes is in phase or out of phase (step S32).

When viewing with one eye (when viewing with one eye alone), it is possible to follow the index with each eye, but with binocular vision, each of the left and right eyes independently follows the index. It is impossible to see. Therefore, the eyeball movement when seeing the index moving forward and backward in the stereoscopic image is either the convergence movement when stereoscopic vision is occurring, or the non-stereoscopic vision is followed by either the left or right eye, and the other eye is synchronized with it. To either.
As for the direction of eye movement, the former is binocular out-of-phase movement, and the latter is binocular in-phase movement. Based on this property,
Automatic and objective measurement can be performed by judging whether or not stereoscopic vision is used.

First, assuming that the average value of the binocular parallax is 0,
As shown in the display case 1 in FIG. 5, normal stereoscopic vision is possible, and in the eyeball movement, an antiphase movement occurs according to the fluctuation of the binocular parallax, and the determination signal from the determination circuit 14 becomes a value of “true”. . Further, the average value of the binocular parallax is sequentially increased until convergence fusion cannot be performed and convergence cannot be obtained. Then, as shown in the display case 2 in FIG. 5, the binocular movement becomes the in-phase movement, and a value of “false” is obtained. The average value of the binocular parallax at this time is the binocular fusion limit of the subject to be obtained, and this is output to the outside (step S33).

[0045]

As described above, according to the present invention, accurate measurement values of visual functions can be obtained objectively and automatically, and the measurement time can be shortened.

That is, in the conventional method of measuring the perceptual / cognitive response to the level of the visual stimulus by the subjective / conscious response, it is performed by the subject's subjective judgment or intentional response. Therefore, in some cases, errors and inaccuracies were lacking, but in the present invention, based on the property that the appearance of eyeballs and gaze movements that are difficult to intervene differ depending on the level of perception and recognition, the level of visual stimulation By measuring the corresponding eye movement, an effect is obtained that an objective response can be obtained.

In the conventional method, the measurement time may be long due to the need for the operation of the experimenter and the subject. However, according to the present invention, the measurement is performed by automatic control. Measurement time can be shortened.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a visual function measuring device to which the present invention is applied.

FIG. 2 is an operation explanatory diagram of the first and second embodiments.

FIG. 3 is a flowchart showing a control procedure according to the first embodiment.

FIG. 4 is a flowchart showing a control procedure according to the second embodiment.

FIG. 5 is an operation explanatory diagram of the third embodiment.

FIG. 6 is a flowchart illustrating a control procedure according to the third embodiment.

[Explanation of symbols]

 2 icon image display device 4 display device 6 stereoscopic image control device 8 eyeball imaging camera 10 eye movement measurement device 12 eye movement measurement circuit 14 judgment circuit 20 control circuit 22 ROM (or RAM: program memory)

Claims (2)

[Claims] 1. An image display means for presenting a visual stimulus for measuring a visual function of a subject, and an eye movement measurement for detecting an eye movement of the subject gazing at the visual stimulus by the image display means. Means, in response to a detection signal output from the eye movement measuring means, a level control means for controlling a level of a visual stimulus presented by the icon display means, and a presentation position of the visual stimulus by the icon display means and And / or determining means for determining whether or not the eye movement of the subject satisfies predetermined requirements based on presentation information including the presentation time, and wherein the visual response to the visual stimulus is the eye movement of the subject. A visual function measuring device that measures a visual function corresponding to each level of the visual stimulus based on a property of being reflected specifically to the visual stimulus. 2. A program for measuring a visual function corresponding to each level of the visual stimulus based on a property that a visual response to the visual stimulus is specifically reflected in an eye movement of the subject. A storage medium, an image display step of presenting a visual stimulus for measuring the visual function of the subject, and an eye movement measuring step of detecting an eye movement of the subject gazing at the visual stimulus, A level control step of controlling a level of a visual stimulus presented by the icon display step in response to a detection signal obtained by the eye movement measuring step; and a presentation position and / or a presentation time of the visual stimulus by the icon display step Determining whether or not the eye movement of the subject satisfies predetermined requirements based on the presentation information including Function measuring storage medium vision, characterized in that has been stored in.