JP2010233978A - Visual performance inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a visual performance inspection device by which visual performance can more exactly be obtained. <P>SOLUTION: The visual performance inspection device which inspects visual performances of a subject is provided with: a visual field measurement part which has a visual target presentation part for sequentially presenting stimulus visual targets to a plurality of measurement points at the fundus of an eye to be inspected, and obtains responses of visual recognition of the subject to the stimulus targets at each measurement point to subjectively measure a sensitivity threshold of the retina; a retina function measurement part which has a stimulus light irradiation part for irradiating the fundus with visible stimulus light, a fundus image photographing part for acquiring a first fundus image of the eye to be inspected before irradiation or in irradiation of the visible stimulus light, and acquiring a second fundus image after irradiation of the stimulus light, and an operation part for comparing the first and second fundus images with each other using image processing, and acquires retina function information of the eye to be inspected; and a control part which displays the sensitivity threshold obtained in the visual field measurement part and the retina function information obtained in the retina function measurement part on a monitor. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a visual function testing device that tests the visual function of an eye to be examined.

  As a method for obtaining the visual function of the eye to be examined, a visual field inspection is known in which a visual target is presented to the eye to be examined and a subjective visual field is measured. As a device for obtaining such a visual field of the eye to be examined, a stimulus target is presented on an electronic display panel such as an LCD (Liquid Crystal Display), the position and brightness of the stimulus target are changed, and the target is visually recognized. There is known a method of inspecting a threshold value of minimum luminance at which a visual target cannot be seen by obtaining a response of the subject whether or not it can be performed (for example, see Patent Document 1).

JP 2003-235800 A

  However, in visual field inspection, since visual function based on the subjective response of the subject is examined, it is difficult to perform objective evaluation. Even if an abnormal value is obtained at a certain measurement point, it is difficult to determine whether the cause is due to abnormalities in the retina, or whether there is an abnormality in the retina or the nervous system after the optic nerve (for example, the chiasm or brain). .

  An object of the present invention is to provide a visual function inspection device capable of obtaining the visual function of a subject more accurately in view of the above-described problems of the prior art.

In order to solve the above problems, the present invention is characterized by having the following configuration.
(1) In a visual function testing device for examining a visual function of a subject, the visual function testing device includes a target presentation unit that sequentially presents stimulus targets to a plurality of measurement points on the fundus of the subject's eye. A visual field measuring unit that subjectively measures a sensitivity threshold of the retina by obtaining a visual recognition response of the subject with respect to the stimulus target, a stimulus light irradiation unit that emits visible stimulus light to the eye fundus of the subject, A fundus image photographing unit that obtains a first fundus image of the subject eye before or at the time of irradiation of the visible stimulus light, and obtains a second fundus image of the subject eye after the irradiation of the visible stimulus light; A calculation unit that compares two fundus images using image processing, a retinal function measurement unit that acquires retinal function information of the eye to be examined, the sensitivity threshold obtained by the visual field measurement unit, and the The retinal function information obtained by the retinal function measurement unit is displayed on the monitor. And a control unit to be shown.
(2) In the visual function testing device of (1), the control unit acquires a plurality of local retinal function information corresponding to the plurality of measurement points from the retinal function information acquired by the retinal function measurement unit. The plurality of local retinal function information and the sensitivity threshold value at the plurality of measurement points are compared.
(3) In the visual function testing device according to (2), the control unit displays a comparison result between the plurality of local retinal function information and the sensitivity threshold values at the plurality of measurement points on a monitor. To do.
(4) In the visual function testing device according to (3), the control unit displays a sensitivity threshold for the plurality of measurement points and at least one of the retinal function information and the local retinal function information on the same screen of the monitor. It is characterized by being displayed.

  According to the present invention, the visual function of a subject can be obtained more accurately.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of an optical system of a visual function inspection device according to an embodiment of the present invention, and FIG. 2 is a block diagram of a control system. The apparatus of the embodiment includes a mechanism of a perimeter that subjectively inspects the visual field, and a mechanism for objectively measuring retinal function (retinal sensitivity).

  Infrared light that illuminates the fundus of the eye E is emitted from the light source 1. It is also possible to obtain an infrared light beam using a halogen lamp and an infrared light transmission filter. The infrared light beam from the light source 1 illuminates the ring slit 4 via the condenser lens 2 and the cold mirror 3 placed on the optical axis L1. The light flux from the ring slit 4 forms an intermediate image near the opening of the perforated mirror 6 through the relay lens 5 and is reflected by the peripheral surface of the perforated mirror 6 placed on the optical axis L2. The ring slit light beam reflected by the perforated mirror 6 is once imaged in the vicinity of the pupil of the eye E by the objective lens 7, and then diffused to uniformly illuminate the fundus of the eye to be examined. The cold mirror 3 has a characteristic of reflecting visible light and transmitting infrared light. Further, flash light (visible light) emitted from a light source 8 composed of a xenon flash lamp passes through a condenser lens 9 and then is reflected by a cold mirror 3 to be ring slit 4, relay lens 5, perforated mirror 6, objective lens. 7 illuminates the fundus of the eye E to be examined. With such a configuration, an illumination optical system is configured. In this embodiment, the optical system from the light source 8 to the objective lens 7 includes an optical system that irradiates the eye fundus with visible stimulus light when measuring objective retinal functions, and an illumination optical system for color photography. Doubles as

  A reflected light beam (infrared light beam) from the fundus of the eye E passes through the objective lens 7, the perforated mirror 6, and the lenses 10, 11, and 12 disposed on the optical axis L 2, and then reflects the infrared light to be visible. The light is reflected by a beam splitter 13 having a property of transmitting light. Then, the light is guided to the lens 14 and imaged on the light receiving surface of the observation CCD camera 15 having sensitivity in the infrared region. The hole of the perforated mirror 6 is at a position conjugate with the pupil of the eye to be examined and has a role of an imaging aperture. The lens 11 is a focusing lens that can be driven in the optical axis direction. By changing the position of the lens 11 on the optical axis L2, the fundus of the subject eye E and the light receiving surface of the camera 15 can be in a conjugate relationship. it can. An infrared imaging optical system that also serves as an observation optical system is configured by the camera 15 from the objective lens 7.

  The imaging optical system using visible light shares the objective lens 7 to the beam splitter 13 of the observation optical system. The visible reflected light beam from the fundus that has passed through the beam splitter 13 is reflected by the mirror 17 via the lens 16 and then enters the CCD camera 18 for imaging having sensitivity in the visible range, and the fundus image is formed on the light receiving surface. Imaged. The light receiving surface of the camera 15 is placed so as to be optically conjugate with the light receiving surface of the camera 18 and the fundus of the eye to be examined. The shooting angle of view for visible imaging and infrared imaging is 45 degrees.

  The visual target presenting optical system for performing the subjective visual field measurement is an electronic display panel that shares the objective lens 7 to the lens 16 used as the imaging optical system and presents the reduction lens 19 and the visual target for visual field measurement. It is composed of an LCD 20. Note that the presentation of the target is not limited to the LCD. A liquid crystal projector or the like may be used as long as it is an electronic display panel. In addition, the display panel is not limited to an electronic display panel, and a display plate in which a plurality of light emitting elements are arranged in an array may be used. The reduction lens 19 is used to project the entire target display area of the LCD 20 onto the eye E. At the time of visual field measurement (at the time of target presentation), the mirror 17 is retracted out of the optical path. The target formed on the LCD 20 is projected onto the fundus of the eye E through the reduction lens 19, the lens 16, the beam splitter 13, the lenses 10, 11, 12, the perforated mirror 6, and the objective lens 7. A fixation target (for example, a cross shape) that is a fixation target of the eye to be examined is formed at the center (optical axis L2) of the LCD 20. The fixation target is not limited to the configuration displayed at the center of the LCD 20, and may be configured to display a visual target for inducing fixation at the periphery of the LCD 20. In addition, the inspection target (stimulus target) for visual field measurement can be configured to change its presentation position, target luminance, target size, target color (red, green, blue, etc.). The Such an optotype presenting optical system constitutes an optotype presenting unit in cooperation with the control unit.

  In FIG. 2, the control unit 30 drives and controls the entire system of the ophthalmologic apparatus. The control unit 30 is connected to the observation light source 1, the light source 8, the LCD 20, the image processing unit 32, the image switching unit 33, the memory 34 as a storage unit, and the response button 35. The response button 35 is used (responds) when the subject can visually recognize the presented target at the time of visual field measurement. The control unit 30 includes a photographing button 37a, a fundus photographing mode, a visual field measurement mode, a mode switching button 37b for switching modes such as a retinal function measurement mode, a start button 37c for starting measurement, and the like. The part 37 is also connected. Note that a fixation target and an inspection target in the LCD 20 can also be set using the control unit 37.

  An image processing unit 32 is connected to the cameras 15 and 18. The image processing unit 32 performs image processing on an image obtained by the camera 18. Further, the image processing unit 32 is configured to perform image processing on an image obtained by the camera 15. The image switching unit 33 is connected to the monitor 31 and switches the display on the monitor 31 to a moving image observation image of the camera 15 or a still image from the camera 18 in response to an instruction from the control unit 30. In the memory 34, images taken by the cameras 15 and 18, field-of-view data as response information of the subject obtained in field-of-view measurement, and objective retinal functions obtained by calculating the photographed images Information is stored. In addition, the memory 34 stores setting information of the presentation position, brightness, and size of the presentation target in the visual field measurement. Furthermore, a program for presenting a visual target to the subject and allowing the control unit 30 to automatically perform visual field measurement based on information from the response button 35 is stored. In addition, the control unit 30 performs arithmetic processing for retinal function and arithmetic processing during subjective visual field measurement.

  In this way, the visual field measuring unit is configured by the optotype presenting optical system, the response button, the control unit, and the like. The illumination optical system (stimulation light illumination unit), imaging optical system (fundus image imaging unit), control unit (calculation unit), and the like constitute a retinal function measurement unit.

  The operation of the visual function testing device having the above configuration will be described. In this embodiment, after measuring the subject's subjective visual field, the objective retinal function measurement of the subject is performed, and whether or not the subject's disease or symptom is caused by the fundus is confirmed from the information To do. Specifically, by comparing the visual field data, which is the response information of visual field measurement, with the retinal function information, it is estimated whether the subject's symptom or disease is a fundus symptom or disease, and the examiner determines Make it easy to do.

  With the switching button 37b, an objective retinal function measurement mode, a subjective visual field measurement mode, and a fundus photographing mode can be selected. Hereinafter, a case where the objective retinal function measurement mode is executed following the subjective visual field measurement mode will be described.

  When the subjective visual field measurement mode is set by the switching button 37b, the light source 1 is turned on by the control unit 30. The fundus of the eye to be examined illuminated with infrared light is imaged by the camera 15. While observing the fundus image displayed on the monitor 31, the examiner operates a joystick (not shown) to move the optical system with respect to the eye to be examined, and aligns the apparatus with respect to the eye to be examined. Further, the examiner performs focusing on the fundus by focusing the fundus image by moving the lens 11 in the optical axis direction. The mirror 17 is placed at a position off the optical path, and a fixation target is formed at the center of the LCD 20 (on the optical axis L2). The eye to be examined is caused to fixate the fixation target of the LCD 20.

  After alignment and focusing, the examiner presses the measurement start button 37c to perform subjective visual field measurement. Here, the control unit 30 executes the visual field measurement program stored in the memory 34 to obtain visual field data of the eye to be examined.

  The control unit 30 determines the luminance, size, and position of the stimulus target to be presented on the LCD 20 based on the settings on the perimeter side stored in the memory 34. FIG. 3 is a diagram showing visual field data 50 obtained by visual field measurement. The response sensitivity to the target presented for each measurement point of the fundus is displayed. The target presentation positions (measurement points) are, for example, 76 locations from the center of the fundus to the periphery. For convenience of explanation, in FIG. 3, the response sensitivity (threshold value) of each measurement point with respect to the visual target is indicated by a numerical value. The target luminance is set with the brightest luminance being set to 0 db as a reference, and the relative luminance is indicated by a numerical value from this value.

  In the visual field measurement, the control unit 30 first sets the target luminance of each measurement point presented on the LCD 20 as described above, and starts the target presentation. When there is a response signal of the response button 35 from the subject (when it has been viewed), the control unit 30 sequentially lowers the luminance presented at the measurement point by a predetermined luminance (4 db) (darker). To do). If the response from the subject cannot be obtained after lowering the luminance of the target, the target is increased (increased) by a predetermined luminance. Before and after the presence or absence of the visual response, the luminance is increased or decreased by 1 db, and the darkest luminance that is finally visually recognized is set as a threshold value at the measurement point. This is performed for each measurement point. When the visual field measurement at all measurement points on the fundus is completed, the response sensitivity (threshold value) at each measurement point is stored in the memory 34 as visual field data 50 as shown in FIG. At this time, the control unit 30 causes the memory 34 to store information obtained by superimposing the threshold values of all measurement points on the fundus image obtained by the camera 15. The visual field measurement may be performed manually by the examiner. By operating the buttons of the control unit 37, the target luminance, the presentation position, and the like are changed, and the threshold value is obtained for each measurement point as described above.

  When the subjective visual field measurement is completed, the examiner switches to the objective retinal function measurement mode by the mode switching button 37b. In retinal function measurement started by pressing the measurement start button 37c, at least two fundus images, an observation image A and an observation image B, are acquired before and after light emission from the light source 8, as shown in FIG. It should be noted that the visual target presented by the visual field measurement does not have luminance, size, or the like that hinders dark adaptation of the eye to be examined. For this reason, retinal function measurement requiring dark adaptation can be performed with the eye to be examined in a state in which alignment and focusing are performed by visual field measurement.

  In response to the trigger signal from the measurement start button 37 c, the control unit 30 captures the fundus image illuminated by the infrared light with the camera 15 and stores this observation image (first fundus image) A in the memory 34. After acquiring the image A, the light source 8 emits light after a certain time (0.5 seconds later), and the eye to be examined is irradiated with visible stimulus light. At this time, the control unit 30 also performs visible imaging of the fundus of the eye to be examined. By inserting the mirror 17 in the photographing optical path in synchronization with the light emission of the light source 8, the visible reflected light beam from the fundus is guided to the camera 18, and a visible fundus image is captured. The visible fundus image (color fundus image) captured by the camera 18 is stored in the memory 34. When the visible imaging is completed, the control unit 30 retracts the mirror 17 out of the optical path again. Subsequently, the fundus image illuminated again with infrared light after a certain time from the light emission of the light source 8 (0.5 seconds to 3 seconds, preferably 0.5 seconds, which is a short time after the stimulation light emission). Is captured by the camera 15, and this observation image (second fundus image) B is stored in the memory 34.

  When the fundus images A and B can be acquired, the control unit 30 calculates the intrinsic signal change amount indicating the retinal function information by comparing the luminance data of the images A and B before and after the stimulation using image processing. When stimulating retinal cells with visible light, nerve cell activity occurs, oxygen consumption and cellular tissue changes occur, and the intensity of infrared reflected light before and after visible stimulating light changes. For this reason, by comparing the luminances of the two images before and after the irradiation of the visible stimulus light, an endogenous signal change amount indicating the retinal function information can be obtained. At this time, the control unit 30 acquires a plurality of local retinal function information corresponding to the measurement points in the visual field data based on the visual field data (or information on the target presentation position) stored in the memory 34.

  In one example of this embodiment, a value (Pb / Pa) obtained by dividing the luminance Pb of the observation image B by the luminance Pa of the observation image A is obtained as the intrinsic signal change amount S1. The intrinsic signal change amount S1 is determined at each measurement point (76 sites) on the fundus shown in FIG. 3 in correspondence with each measurement point of subjective visual field measurement, and is stored in the memory 34 (retina) Enter feature information). When comparing the two images A and B, since there is a minute movement of the eye to be examined, the deviation between both is corrected by a method of matching the feature points (for example, optic nerve head and blood vessels) common to both eyes. It is preferable to align.

  When the retinal function measurement is completed, the control unit 30 analyzes the visual function of the subject. FIG. 5 is a schematic diagram illustrating a method for analyzing visual function. The control unit 30 aligns the visual field data 50 and the retinal function information 60, and compares the threshold value of the visual field data with the retinal function information corresponding to the part of the threshold value.

  In a region where the retinal cells are not active, the value of the endogenous signal change amount S1 approaches 1 (the luminance change of the images A and B is small). On the other hand, at a site where nerve cells are active, the endogenous signal S1 shows a low value (close to 0). Therefore, at the measurement point where the value of the intrinsic signal change amount S1 is close to 1, the sensitivity to the light of the retina is low, in other words, the threshold value of the visual field data is low. In addition, the threshold value of the visual field data becomes high at the measurement point at the part where the endogenous signal change amount S1 is lower than a certain threshold value.

  However, for example, when attention is paid to a certain measurement point, the numerical value (endogenous signal change amount S1) of the retinal function information is low (the retinal function is high) even though the threshold value of the visual field data is low (the sensitivity is low). Contrary to the above description. In such a case, in this embodiment, the retinal function is normal at the measurement point, but there is a possibility that the threshold value of the visual field data has become low due to the functional deterioration of the retinal and later (optic nerve, chiasm, brain). In addition, when the threshold value of the visual field data is high (high sensitivity), but the numerical value of the retinal function information is high (low retinal function), the subject erroneously presses the response button 35 and performs inaccurate visual field measurement. It may have become. In such a comparison between the visual field data and the retinal function information, a reference value is stored in the memory 34 as a reference for a comparison difference, and the control unit 30 calculates based on the reference value. The control unit 30 sets each measurement point of the visual field data image 50 in which the visual field data is superimposed on the fundus image and the retinal function image 60 in which the retinal function information (endogenous signal change amount S1) is superimposed on the fundus image. When the numerical values are compared, and there is a large difference between the compared numerical values, a mark for prompting the examiner's attention is displayed at the corresponding measurement point on the visual field data image. For example, when it is suspected that the function of the part after the retina is deteriorated, the control unit 30 surrounds the corresponding measurement point with a mark 75a having a predetermined shape (for example, a circular shape), and the measurement in which the subject is suspected to be wrong. The point is displayed so as to be surrounded by a mark 75b (for example, a square shape) having a different shape from the mark 75a. Such visual field data image 50 and retinal function image 60 are displayed side by side on the same screen of the monitor 31, thereby making it easier to confirm. In the present embodiment, the mark for caution is displayed on the visual field data image 50. However, the present invention is not limited to this, and the mark can be formed on the retinal function image 60 or another new fundus image. . Further, the mark for calling attention may be displayed on a fundus image different from the visual field data image or the retinal function image, or may be displayed on an image obtained by comparing the visual field data image and the retinal function image.

  In this way, the examiner can easily grasp the visual function of the subject, and can obtain the visual function of the subject more accurately. Since the calculation of the control unit 30 estimates the measurement points of the subjective examination and the objective examination, it becomes easy for the examiner to determine whether the subject's symptom or disease is caused by the fundus symptom or disease. . In addition, the accuracy of the subject's perimeter can be confirmed.

  Note that the above embodiment can be variously modified. For example, as for the endogenous signal change amount by objective measurement, it is only necessary to obtain information indicating the change amount between the intrinsic signal in the fundus image before stimulation and the intrinsic signal in the fundus image after stimulation. For example, a value (Pb−Pa) obtained by subtracting the light amount Pa of the observation image A from the light amount Pb of the observation image B stored in the memory 34 may be used. In addition, by incorporating the optical system and arithmetic processing system for objectively measuring the retinal function as described above into the perimeter device, it is possible to share the optical system and the like, saving space and economically. Can also be an advantageous device.

  In the present embodiment described above, the processing for comparing the measurement points corresponding to the visual field data and the retinal function information is performed. However, the present invention is not limited to this. Any configuration that can easily determine whether the subject's symptom or disease is caused by a fundus symptom or disease may be used. For example, either the visual field data or the retinal function information may be displayed as an image display such as gradation display (gradation display) based on numerical values, and the other numerical information may be aligned and displayed. For example, when the visual field data is displayed as a grayscale image, if the numerical value of the retinal function information of the part having the visual field defect is low, it becomes easy for the examiner to determine the functional deterioration of the part after the retina.

  In the above-described embodiment, the retinal function measurement is performed after the visual field measurement. However, the present invention is not limited to this. Any structure that can easily determine the visual function of the subject may be used, and the order of measurement may be reversed. However, in retinal function measurement, since there is optical stimulation by visible light, it is necessary to perform visual field measurement after dark adaptation of the subject. Therefore, the visual function test is more efficient when the retinal function measurement is performed after the visual field measurement.

  Further, in the present embodiment described above, the patient's eye is aligned using a fixation lamp to perform retinal function measurement and visual field measurement, but the present invention is not limited to this. The configuration is not limited to using a fixation lamp. For example, in retinal function measurement, a feature may be added in which feature points of the fundus are extracted, and movements such as eye movements of the eye to be examined are monitored and tracked in real time. Thereby, the change of the same part on the retina can be measured in the comparison of different fundus images. In the visual field measurement, the threshold value of a specific measurement point can be measured by changing the position of the target to be presented on the LCD in accordance with the movement of the fundus.

  In the above-described retinal function measurement according to the present embodiment, a fundus image illuminated with infrared light is acquired and compared. However, the present invention is not limited to this. Any configuration that can measure the retinal function is acceptable. For example, a color fundus image illuminated with visible light is acquired before or after irradiation with visible stimulus light, or after photographing using visible illumination light for photographing as visible stimulus light. A method of acquiring a fundus image (after stimulation light irradiation) and performing a comparison operation may be used. Specifically, a color fundus image is acquired simultaneously with the irradiation of visible stimulus light (flash light), and the color fundus image is acquired by irradiating flash light again after photographing. Thereafter, the retinal function information is obtained by performing a comparison operation on the color fundus image. In this case, the photobleaching reaction of the retina can be measured, and the function of photoreceptor cells can be mainly measured.

It is the figure which showed the optical system of the visual function test | inspection apparatus in this embodiment. It is the block diagram which showed the control system of the visual function test | inspection apparatus in this embodiment. It is the figure which showed visual field data. It is a timing chart explaining retinal function measurement. It is a schematic diagram explaining the method of analyzing a visual function.

1, 8 Light source 15 Observation camera 19 Reduction lens 20 LCD
30 Control Unit 31 Monitor 32 Image Processing Unit 34 Memory 35 Response Button

Claims (4)

In a visual function testing device for examining the visual function of a subject,
A visual target presenting unit for sequentially presenting a stimulus target to a plurality of measurement points on the fundus of the subject's eye, and obtaining a response of visual recognition of the subject to the stimulus target at each measurement point to obtain sensitivity of the retina A visual field measurement unit for measuring the threshold value,
A stimulation light irradiating unit configured to irradiate the fundus of the subject's eye with visible stimulus light; and a first fundus image of the eye to be examined before or during the irradiation of the visible stimulus light; A fundus image capturing unit that acquires a second fundus image of the optometry, and a calculation unit that compares the first and second fundus images using image processing, and acquires retinal function information of the eye to be examined A retinal function measuring unit;
A control unit that causes the monitor to display the sensitivity threshold obtained in the visual field measurement unit and the retinal function information obtained in the retinal function measurement unit;
A visual function testing device comprising: 2. The visual function testing device according to claim 1, wherein the control unit acquires a plurality of local retinal function information corresponding to the plurality of measurement points from the retinal function information acquired by the retinal function measurement unit. A visual function testing device that compares local retinal function information with the sensitivity thresholds at the plurality of measurement points. The visual function testing device according to claim 2,
The control unit displays a comparison result between the plurality of local retinal function information and the sensitivity threshold values at the plurality of measurement points on a monitor. The visual function testing device according to claim 3,
The visual function inspection device, wherein the control unit displays a sensitivity threshold for the plurality of measurement points and at least one of the retinal function information and the local retinal function information on the same screen of a monitor.

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