JP2012050535A - Visual function inspecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a visual function inspection apparatus which can suitably evaluate sensitivity of the visual cell on the fundus.SOLUTION: The visual function inspection apparatus includes: a fundus imaging optical system which receives luminous flux from the fundus to be inspected by a light receiving element to pick up a fundus image; a stimulation light irradiation optical system which emits retina stimulation light so as to form a stimulation area and a non-stimulation area within the imaging range of the fundus imaging optical system in the fundus of a subject eye; an imaging control unit which controls the stimulation light irradiation optical system to irradiate the fundus with the stimulation light, to receive the light spontaneously emitted from the fundus using the light receiving element without irradiating the fundus with light after irradiation with the stimulation light, and to acquire a fundus image after irradiation of the stimulation light on the basis of output signals from the light receiving element; and a calculation means which analyzes luminance distribution of the fundus image picked up by the fundus imaging optical system to measure the visual function of the eye to be inspected.

Description

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

  2. Description of the Related Art Conventionally, there is known an apparatus that acquires fundus images before and after retinal stimulation by stimulation light, performs arithmetic processing on these fundus images, extracts an intrinsic signal of the retina, and measures a retinal function (see Patent Document 1). .

JP 2006-136379 A

  However, in the case of a conventional device, when obtaining a fundus image after stimulation, a reflection image is obtained when illumination light is irradiated on the entire fundus, so the intrinsic signal includes the effect of stimulation by illumination light. It was. Moreover, when acquiring an intrinsic signal, there was no choice but to use a temporal luminance change.

  An object of the present invention is to provide a visual function testing device capable of suitably evaluating the sensitivity of photoreceptor cells on the fundus in view of the above-described conventional technology.

  In order to solve the above problems, the present invention is characterized by having the following configuration.

(1)
A fundus imaging optical system that receives a light beam from the fundus of the subject's eye with a light receiving element and captures a fundus image;
A stimulation light irradiation optical system that irradiates retinal stimulation light so that a stimulation region and a non-stimulation region are formed within the imaging range of the fundus imaging optical system in the subject's eye fundus;
The stimulation light irradiation optical system is controlled to irradiate the fundus with the stimulation light. After the stimulation light is irradiated, light is emitted from the fundus without using the light receiving element. And an imaging control unit that acquires a fundus image after irradiation of stimulation light based on an output signal from the light receiving element;
Arithmetic means for analyzing the luminance distribution of the fundus image captured by the fundus imaging optical system and measuring the visual function of the eye to be examined;
It is characterized by providing.
(2)
The visual function testing device according to (1), wherein the stimulation light irradiation optical system irradiates a part of the fundus with retinal stimulation light so that stimulation regions and non-stimulation regions are alternately formed.
(3)
The visualizing device according to (2), wherein the calculation means acquires positional information of the stimulation region in a fundus image captured by the fundus imaging optical system, and obtains a relative luminance change in the stimulation region. Functional inspection device.
(4)
(3) The calculation unit obtains positional information of the non-stimulation region in a fundus image captured by the fundus imaging optical system, and calculates a relative luminance change in the non-stimulation region. Visual function testing device.
(5)
The stimulation light irradiation optical system has a light control device that is disposed at a position substantially conjugate with the fundus of the subject's eye and that controls the progress of light emitted from the light source,
The visual function testing device according to (4), wherein the imaging control unit controls the light control device to irradiate the fundus with stimulation light.
(6)
The optical function testing device according to (5), wherein the light control device is a micromirror device or a liquid crystal panel.
(7)
The light control device is disposed in a common optical path of the stimulation light irradiation optical system and the fundus imaging optical system, and combines light guide control from the light source to the fundus and light guide control from the fundus to the light receiving element. The visual function testing device according to (6).
(8)
The imaging function testing device according to (7), wherein the imaging control unit controls a stimulation light irradiation optical system to control an irradiation light amount of the stimulation light.
(9)
The optical control device according to (8), wherein the light control device has a curved shape corresponding to a fundus shape of an eye.

  According to the present invention, the sensitivity of photoreceptor cells can be suitably evaluated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an optical system and a control system of a visual function testing device according to this embodiment. FIG. 2 is a diagram showing an example of a two-dimensional pattern image irradiated on the fundus as retinal stimulation light. FIG. 3 is a diagram illustrating an example of a fundus image when the retina is stimulated. The figure numbers are reference numbers and are not limited to the illustrated configuration.

  The optical system of this apparatus receives stimulation light irradiation optical system 100 that irradiates a fundus oculi Ef of a subject's eye E with a two-dimensional pattern image as retinal stimulation light, and a light beam from the fundus oculi Ef is received by a light receiving element 206. A fundus imaging optical system 200 that captures an image. The light guide optical system 300 (for example, a dichroic mirror, an objective lens, etc.) guides light from the irradiation optical system 100 to the fundus and guides light from the fundus to the imaging optical system 200.

  The arithmetic control unit 80 controls the irradiation optical system 100 to project a pattern image on the fundus oculi Ef. In addition, the arithmetic control unit 80 controls the imaging optical system 200 to acquire a fundus image based on an output signal from the light receiving element 206.

  For example, the irradiation optical system 100 includes a light control device 104 (for example, a micromirror device or a liquid crystal panel) that controls the traveling state of light emitted from the light source 102, and the arithmetic control unit 80 includes the light control device 104. The pattern image is irradiated onto the fundus oculi Ef by controlling. Moreover, the structure by which the light-shielding plate in which the opening corresponding to a pattern image was formed in the optical path of the irradiation optical system 100 may be arrange | positioned.

  The imaging optical system 200 includes a light receiving optical system that causes a light beam from the fundus to enter the light receiving element 206. For example, the imaging optical system 200 is provided with an optical scanner 204 that changes the traveling direction of the light flux from the fundus. As the optical scanner 204, for example, a galvano mirror, a polygon mirror, a micro mirror device, an acousto-optic deflection element, or the like can be considered. In such a case, for example, a light receiving element having a single light receiving surface (a one-dimensional CCD is used in the case of line scanning) is provided as the light receiving element 206. Note that a fundus image may be acquired using a two-dimensional image sensor without using an optical scanner. In addition, the imaging optical system 200 may be provided with a liquid crystal panel.

  The imaging optical system 200 receives the light spontaneously emitted from the fundus by the stimulation light without emitting the illumination light to the fundus after the irradiation of the stimulation light. Thereby, since a retina is not stimulated when obtaining a fundus image, a reaction due to stimulation light is detected with high accuracy. The imaging optical system 200 is appropriately provided with an optical filter that selectively transmits light having a predetermined wavelength.

  For the index projected on the fundus, for example, an index such as a vertical stripe pattern in FIG. 2A and a geometric pattern such as a multiple ring pattern in FIG. 2B is projected. Also, an inspection target (for example, a Landolt ring) used for the subjective visual acuity test may be projected. That is, in the region corresponding to the imaging range of the imaging optical system 200 in the fundus oculi Ef, the stimulation light is irradiated to a part on the fundus so that the stimulation region and the non-stimulation region are formed.

  In addition, the projection target may be a dynamic index that changes with time, or may be a static index. In the case of a dynamic index, the position, color, brightness, shape, and the like of the index change with time. For example, the brightness of the index is alternately changed, or the projection position of the index is sequentially changed. The indicator is changed continuously or stepwise or intermittently. Thereby, the irradiation region and non-irradiation region of the stimulation light on the fundus oculi Ef are temporally changed. In this case, the projection position is controlled such that the fundus region corresponding to the imaging range by the imaging optical system 200 is irradiated with the stimulation light, and as a result, a wide range of examinations can be performed.

  By controlling the irradiation wavelength of the stimulation light and changing the color of the index, it is possible to stimulate specific photoreceptor cells that are sensitive to a certain wavelength. For example, when red light is irradiated, cells having sensitivity to red (long wavelength cones) are stimulated. In this case, as the light source 202, a light source corresponding to each wavelength is arranged. Alternatively, the index color is set by a combination of white light and a wavelength selection filter.

  By controlling the irradiation light quantity of the stimulating light and changing the brightness of the index, the difference in photoreceptor response due to the change in brightness is measured. The brightness is adjusted according to the sensitivity of the photoreceptor cells. For example, the viability of a photoreceptor cell is examined in more detail by irradiating intense stimulating light in a photoreceptor cell region where reaction is poor.

  The arithmetic control unit 80 measures the visual function of the eye E by analyzing the luminance distribution of the fundus image captured by the imaging optical system 200. The relationship between the irradiation position of the stimulation light by the light control device 104 and the scanning position by the optical scanner 204 is set in advance, and the position information (irradiation position information) of the stimulation area and the position information of the non-stimulation area in the captured fundus image Is obtained. In addition to the configuration of the optical system, the arithmetic control unit 80 is connected to a memory 72, an operation unit 74, a display monitor 75, and the like. For example, the memory 72 can continuously accumulate acquired fundus images. The operation unit 74 outputs an operation signal corresponding to the operation of the examiner, for example, between a mode in which a fundus projection index is set or a fundus image is obtained through stimulation and a mode in which a fundus image is obtained without stimulation. The mode is switched. The monitor 75 displays an alignment screen, a visual function test result, and the like.

  For example, the arithmetic control unit 80 obtains the relative luminance of the stimulation area and the non-stimulation area in the captured fundus image.

  In addition, the arithmetic control unit 80 acquires a fundus image over time, and obtains a relative luminance change in the stimulation region. In addition, the arithmetic control unit 80 acquires the fundus image over time and obtains a relative luminance change in the non-stimulus region.

  The arithmetic control unit 80 identifies a region where the luminance changes or a region where there is no change. At this time, the arithmetic control unit 80 analyzes, for example, time-series luminance information. For example, a time-series change amount, change rate, and change speed relating to the luminance distribution are measured. For example, the arithmetic control unit 80 graphically displays the luminance level in a plurality of stages, and simultaneously displays luminance information at different times (see FIG. 3).

  FIG. 3 is an example showing a temporal change of the luminance distribution when the vertical stripe pattern of FIG. 2A is projected as stimulation light. Note that the spontaneous fluorescence due to the stimulation light is generated for several seconds to several tens of seconds. In FIG. 3, the portion (H1) where the number of hatching pitches is large indicates a portion where the luminance level is abnormally large compared to the region (Hs) showing a normal reaction. This occurs when the photoreceptor cells react greatly due to eye disease (eg, edema).

  On the other hand, the portion (H2) where the hatching pitch is small indicates a portion where the luminance level is smaller than the region (Hs) showing a normal reaction. This occurs when the response of the photoreceptor cells is low due to an eye disease (eg, visual field defect).

  Further, the portion without hatching (H0) indicates that the luminance level is zero or the luminance is close to the background. This occurs when the photoreceptor cells are dead for some reason.

  The arithmetic control unit 80 detects the luminance level of the non-stimulation region in the acquired fundus image and compares it with the luminance level of the stimulation region. Thereby, a relative luminance change between the stimulation area and the non-stimulation area is detected. That is, the luminance level in the non-stimulated region can be used as a determination material as the luminance level in the region where the retina is not stimulated.

  Further, it can be used to acquire the intrinsic signal of the photoreceptor cell in the non-stimulation area when the photoreceptor cell reacts in the stimulation light area. In this case, as shown in FIG. 2, in the case of the stimulation light in which the stimulation area and the non-stimulation area are alternately formed, a signal in the non-stimulation area sandwiched between the stimulation areas is obtained. Note that the luminance information in the stimulation area and the non-stimulation area adjacent to each other is compared, so that a local analysis in a portion with the fundus is possible.

  Regarding the relative luminance change, the change amount in the normal eye may be stored in advance in the memory 72 as a database, the change amount in the normal eye and the change amount in the eye E may be compared, and the comparison result may be output. . The arithmetic control unit 80 may perform image processing such as addition averaging on a plurality of captured fundus images to improve the contrast of the image.

  As described above, the retinal stimulation light is irradiated so that the stimulation region and the non-stimulation region are formed, and then the light spontaneously emitted from the fundus is received by the imaging optical system 200, whereby one fundus In the image, information on the area where the retina is stimulated and the area where the retina is not stimulated are acquired. For this reason, an objective examination of the visual function can be performed without acquiring images over time.

<Use of micromirror device or liquid crystal panel>
Below, an example of the irradiation optical system 100 and the imaging optical system 200 is shown. FIG. 4 is a view when a micromirror device is arranged at the fundus conjugate position. The irradiation optical system 100 includes a light source 10 (laser diode, LED, etc.), a condenser lens 12, a micromirror device 14, and an objective lens 16.

  The micromirror device 14 is a device in which micromirrors are separated and arranged in units of hundreds of thousands to millions on a semiconductor substrate, and each micromirror is driven independently. At this time, the micromirror deflects light in a predetermined direction by controlling the applied voltage to each drive unit that drives each micromirror. Then, the arithmetic control unit 80 controls the driving of the micromirror device 14 and controls whether or not the light from the light source 10 is guided to the fundus in each micromirror.

  Each micromirror of the micromirror device 14 is disposed at a position substantially conjugate with the fundus oculi Ef with respect to the objective lens 16. Here, a configuration in which the reflection surface of each micromirror is arranged flat may be used, or a configuration in which the reflection surface of each micromirror is arranged in a curve according to the curved shape of the fundus may be used. Here, since each micromirror is disposed at the fundus conjugate position, the irradiation position and irradiation pattern of the stimulation light on the fundus are directly and arbitrarily controlled by controlling the reflection angle of each micromirror. As a result, a two-dimensional pattern as shown in FIG. 2 is simultaneously projected onto the fundus and retinal stimulation is performed simultaneously. Moreover, a dynamic index is projected on the fundus as stimulation light by changing the reflection angle of each micromirror with time.

  The imaging optical system 200 includes an objective lens 16, a micromirror device 14, a beam splitter 18 (for example, a half mirror), a lens 20, a pinhole plate 22, a lens 23, and a light receiving element 24 (for example, APD: avalanche photodiode). .

  After the stimulation light irradiation, the arithmetic control unit 80 controls the driving of the micromirror device 14 and controls whether or not the light from the fundus is guided to the light receiving element 24 in each micromirror. The arithmetic control unit 80 uses the micromirror device 14 to two-dimensionally control light from the fundus to obtain a fundus image. For example, the position at which light from the fundus is acquired is scanned in the X direction by sequentially controlling the reflection angles of the mirrors arranged in the X direction. When the scanning of the mirrors arranged at a certain position in the Y direction (main scanning) is completed, the control position of the mirror in the Y direction is changed to the next position (sub scanning). Then, main scanning is similarly performed on the mirrors arranged at the next position in the Y direction. In this way, the mirror control position in the Y direction is sequentially changed from the upper direction to the lower direction, and a fundus image for one frame is acquired. And when acquiring a fundus image continuously, the above operation is repeated.

  Since the operation after acquiring the fundus image is the same as the above method, the description thereof is omitted. In the above configuration, the micromirror device 14 is disposed in the common optical path of the irradiation optical system 100 and the imaging optical system 200, and the micromirror device combines the irradiation control of the stimulation light and the acquisition control of the light from the fundus. Thereby, for example, the apparatus is miniaturized. In addition, it becomes easy to associate the irradiation position of the stimulation light with the fundus image. However, the present invention is not limited to the above, and the micromirror device may be used only at least for irradiation with stimulation light.

  FIG. 4 is a view when the liquid crystal panel is arranged at the fundus conjugate position. The irradiation optical system 100 includes a light source 10 (laser diode, LED, etc.), a condenser lens 12, a liquid crystal panel 26, and an objective lens 16.

  In the liquid crystal panel 26, pixels (dots) are two-dimensionally arranged, and the operation control unit 80 controls the shielding and transmission of light incident from the back for each pixel. By controlling the applied voltage corresponding to each pixel of the liquid crystal panel 26, light shielding and transmission are controlled. The arithmetic control unit 80 controls driving of the liquid crystal panel 26 and controls whether or not light from the light source 10 is guided to the fundus in each pixel.

  The liquid crystal panel is disposed at a position substantially conjugate with the fundus oculi Ef with respect to the objective lens 16. Similar to the micromirror device, the liquid crystal panel may have a flat shape or a curved shape.

  Here, since the liquid crystal panel is disposed at the fundus conjugate position, the irradiation position and irradiation pattern of the stimulation light on the fundus are directly and arbitrarily controlled by the control of each pixel. As a result, a two-dimensional pattern as shown in FIG. 2 is simultaneously projected onto the fundus and retinal stimulation is performed simultaneously. In addition, when the light shielding / transmission position is changed with time, a dynamic index is projected on the fundus as stimulation light.

  The imaging optical system 200 includes an objective lens 16, a liquid crystal panel 26, a beam splitter 18 (for example, a half mirror), a lens 20, a pinhole plate 22, a lens 23, and a light receiving element 24 (for example, APD: avalanche photodiode).

  After the stimulation light irradiation, the arithmetic control unit 80 controls the driving of the liquid crystal panel 26 and controls whether or not the light from the fundus is guided to the light receiving element 24 in each pixel. Then, the arithmetic control unit 80 two-dimensionally controls light from the fundus using a liquid crystal panel to obtain a fundus image. For example, by sequentially controlling the pixels arranged in the X direction, the position for acquiring light from the fundus is scanned in the X direction. When the scanning of the pixels arranged at a certain position in the Y direction (main scanning) is completed, the control position of the pixel in the Y direction is changed to the next position (sub scanning). Then, main scanning is similarly performed on the pixels arranged at the next position in the Y direction. In this manner, the pixel control position in the Y direction is sequentially changed from the upper direction to the lower direction, and a fundus image for one frame is acquired. And when acquiring a fundus image continuously, the above operation is repeated.

  Since the operation after acquiring the fundus image is the same as the above method, the description thereof is omitted. In the above configuration, the liquid crystal panel 26 is disposed in the common optical path of the irradiation optical system 100 and the imaging optical system 200, and the liquid crystal panel 26 combines the irradiation control of the stimulation light and the acquisition control of the light from the fundus. Thereby, the apparatus is miniaturized. In addition, it becomes easy to associate the irradiation position of the stimulation light with the fundus image. However, the present invention is not limited to the above, and the liquid crystal panel may be used only at least for the irradiation of the stimulation light.

It is a schematic block diagram shown about the optical system and control system of the visual function inspection apparatus which concern on this embodiment. It is a figure which shows an example of the two-dimensional pattern image irradiated to a fundus as retinal stimulation light. It is a figure which shows an example of the brightness | luminance change of a fundus image when stimulating the retina. It is a figure at the time of arrange | positioning a micromirror device in a fundus conjugate position. It is a figure at the time of arrange | positioning a liquid crystal panel in a fundus conjugate position.

DESCRIPTION OF SYMBOLS 14 Micromirror device 26 Liquid crystal panel 80 Operation control part 100 Stimulation light irradiation optical system 200 Fundus imaging optical system 206 Light receiving element

Claims (9)

A fundus imaging optical system that receives a light beam from the fundus of the subject's eye with a light receiving element and captures a fundus image;
A stimulation light irradiation optical system that irradiates retinal stimulation light so that a stimulation region and a non-stimulation region are formed within the imaging range of the fundus imaging optical system in the subject's eye fundus;
The stimulation light irradiation optical system is controlled to irradiate the fundus with the stimulation light. After the stimulation light is irradiated, light is emitted from the fundus without using the light receiving element. And an imaging control unit that acquires a fundus image after irradiation of stimulation light based on an output signal from the light receiving element;
Arithmetic means for analyzing the luminance distribution of the fundus image captured by the fundus imaging optical system and measuring the visual function of the eye to be examined;
A visual function testing device comprising:   The visual function testing device according to claim 1, wherein the stimulation light irradiation optical system irradiates a part of the fundus with retinal stimulation light so that stimulation regions and non-stimulation regions are alternately formed.   3. The visual field according to claim 2, wherein the calculation unit obtains positional information of the stimulation region in a fundus image captured by the fundus imaging optical system and obtains a relative luminance change in the stimulation region. Functional inspection device.   The said calculating means acquires the positional information on the said non-stimulation area | region in the fundus image imaged by the said fundus imaging optical system, and calculates | requires the relative luminance change in the said non-stimulation area | region. Visual function testing device. The stimulation light irradiation optical system has a light control device that is disposed at a position substantially conjugate with the fundus of the subject's eye and that controls the progress of light emitted from the light source,
5. The visual function testing device according to claim 4, wherein the imaging control unit controls the light control device to irradiate the fundus with stimulation light.   6. The visual function testing device according to claim 5, wherein the light control device is a micromirror device or a liquid crystal panel.   The light control device is disposed in a common optical path of the stimulation light irradiation optical system and the fundus imaging optical system, and combines light guide control from the light source to the fundus and light guide control from the fundus to the light receiving element. The visual function testing device according to claim 6.   The visual function inspection device according to claim 7, wherein the imaging control unit controls an irradiation light amount of stimulation light by controlling a stimulation light irradiation optical system.   The visual function testing device according to claim 8, wherein the light control device has a curved shape corresponding to a fundus shape of an eye.

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