JP6060525B2 - Fundus examination device - Google Patents

Description

  The present invention relates to a fundus inspection apparatus that performs an inspection by projecting an inspection target on the fundus.

  As a fundus examination apparatus, an imaging unit for imaging the fundus of a patient is provided, and a visual target for visual field inspection is projected on the fundus of the patient imaged by the imaging unit to obtain a brightness discrimination threshold value of the target based on the response of the patient What performs a visual field inspection is known (for example, refer to Patent Document 1). In this type of fundus examination device, optic nerve head and optic nerve fiber bundle defects are observed from the obtained fundus image, and the visual function can be evaluated by quantifying the patient's photosensitivity from the measurement result of perimetry, glaucoma etc. Useful for diagnosis.

JP 2011-36273 A

By the way, the photoreceptor cells contained in the patient's fundus (retinal) are generally dense in the fundus center (macular region) and sparse as they reach the periphery, so the fundus center is detected against the stimulus target. While the threshold value is high, the threshold value tends to be low in the fundus periphery.
For this reason, if the size of the inspection target projected on the fundus central part and the peripheral part is the same as in the prior art, the number of photoreceptor cells contained in the stimulus target will change, especially the fundus center. There is a possibility that it is difficult to detect a decrease in visual function sensitivity.

  In view of the above-described problems of the prior art, an object of the present invention is to provide a fundus inspection apparatus that can accurately perform a visual field inspection of the fundus.

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

A fundus inspection apparatus for inspecting the fundus by projecting an inspection target on the inspection position of the fundus of the subject to be examined, comprising a fixation target forming means for forming a fixation target to be presented and guided to the subject eye, An inspection target setting means for setting an inspection position based on an inspection target with respect to the optometry eye fundus, and the inspection target can be projected on the inspection position of the eye fundus corresponding to the inspection position set by the inspection target setting means The inspection of the fixation target based on the coordinates of the fixation target formed by the target projection means , the coordinates of the fixation target formed by the fixation target formation means, and the coordinates of the inspection target set by the inspection target setting means In accordance with the radial distance of the target, the target projection is performed such that the projection diameter of the inspection target that is relatively far from the projection diameter of the inspection target that is relatively close to the radial direction is large. further comprising a control means for controlling the means, And features.

  According to the present invention, the visual field inspection of the fundus can be performed with high accuracy.

  Embodiments of the present invention will be described with reference to the drawings. In the following description, a fundus inspection apparatus capable of performing fundus observation and photographing and visual field inspection of the fundus will be described as an example. FIG. 1 is an external configuration diagram of a fundus examination apparatus. FIG. 2 is an explanatory diagram of an optical system and a control system of the fundus examination apparatus.

  In FIG. 1, a fundus examination apparatus 1 includes a base 1a, a moving base 2 provided so as to be movable in the left and right direction (X direction) and the front and rear (working distance) direction (Z direction) with respect to the base 1a. An imaging unit (apparatus) movably provided in the left / right direction (X direction), the up / down direction (Y direction), and the front / rear direction (X direction) with respect to the patient's eye (eye) E by the drive unit 6 provided on the table 2. Main body) 3 and a face support unit 5 fixed to the base 1a for supporting the patient's face. Note that an optical system and a control system, which will be described later, are housed inside the photographing unit 3.

A joystick 4, a control unit 7a, and a monitor 8 are provided on the examiner side of the imaging unit 3. The joystick 4 is used to move the photographing unit 3 relative to the eye E. When the joystick 4 is tilted, the moving base 2 slides in the XZ direction on the base 1a by the sliding mechanism, and when the rotary knob 4a provided on the side surface of the joystick 4 is rotated, the photographing unit 3 moves in the Y direction. . Note that the switch 4b at the top of the joystick 4 is used to input a trigger signal for photographing the fundus image. The control unit 7a is used for setting various imaging / inspection conditions. As the control unit 7a, a well-known input unit such as a mouse, a keyboard, a touch panel (attached to the monitor 8) or the like is used. In addition to the observation / photographed image of the eye E, various inspection results are displayed on the monitor 8. For example, a fundus observation screen, an anterior ocular segment observation screen, a visual field inspection screen, and the like are displayed on the monitor 8.
On the patient side of the imaging unit 3, there are an imaging window 9 for allowing the patient to look inside the apparatus, and a response button 7b for the patient to input a response signal at the time of visual function inspection of the eyes (retina).

  The optical system in FIG. 2 includes an illumination optical system 10, an observation / imaging optical system 30 for observing and photographing the fundus and anterior eye, a focus index projection optical system 40 for projecting a focus index (focus index) on the fundus, and a patient. It is composed of a fixation target for guiding the line of sight of the eye E and a target presentation optical system 70 for presenting various inspection targets.

<Illumination Optical System> The illumination optical system 10 includes a photographing illumination optical system and an observation illumination optical system. The photographing illumination optical system includes a photographing light source 14 that emits a visible light beam, a condenser lens 15, a ring slit 17 having a ring-shaped opening, a relay lens 18, a mirror 19, a black spot plate 20 having a black spot at the center, a relay lens 21, A perforated mirror 22 and an objective lens 25 are provided.
The observation illumination optical system includes an illumination light source 11 that emits a near-infrared light beam, an infrared filter 12 that transmits near-infrared light, a condenser lens 13, and a dichroic disposed between the condenser lens 13 and the ring slit 17. An optical system from the mirror 16 and the ring slit 17 to the perforated mirror 22 and an objective lens 25 are provided.

<Observation / Photographing Optical System> The observation / photographing optical system 30 includes a fundus observation optical system, a fundus photographing optical system, and an anterior ocular segment observation optical system. The fundus oculi observation optical system includes an objective lens 25, a photographing aperture 31 located in the vicinity of the aperture of the perforated mirror 22, a focusing lens 32 movable in the optical axis direction, an imaging lens 33, and a flip-up mirror 34. In the optical path in the reflection direction of the flip-up mirror 34, a dichroic mirror 37 having infrared light reflection / visible light transmission characteristics, a relay lens 36, and an observation two-dimensional imaging device 38 having sensitivity in the infrared region are disposed. A fundus image illuminated with an infrared light source is captured by the image sensor 38. The flip-up mirror 34 is inserted into the optical path by the insertion / removal mechanism 39 when the fundus is observed, and is removed from the optical path when the fundus is photographed.
The fundus photographing optical system shares the objective lens 25 and the optical system from the photographing aperture 31 to the imaging lens 33 with the fundus observation optical system. The fundus photographing optical system includes a photographing two-dimensional imaging device 35 having sensitivity in the visible range, and the fundus image illuminated by the visible light source 14 is photographed by the imaging device 35. The photographing aperture 31 is placed at a position substantially conjugate with the pupil of the eye E. The focusing lens 32 is moved along the optical axis by a moving mechanism 49 including a motor.

  With the above configuration, when observing the fundus, the luminous flux emitted from the illumination light source 11 is once converged near the pupil of the eye E by the objective lens 25 and then diffused to illuminate the fundus. Reflected light from the fundus is obtained through an imaging element 38 via an objective lens 25, an aperture of a perforated mirror 22, a photographing aperture 31, a focusing lens 32, an imaging lens 33, a flip-up mirror 34, a dichroic mirror 37, and a relay lens 36. To form an image. At the time of photographing the fundus, the reflected light from the fundus illuminated by the photographing light source 14 passes through the objective lens 25, the aperture of the perforated mirror 22, the photographing aperture 31, the focusing lens 32, and the imaging lens 33 to the two-dimensional imaging device 35. Form an image.

  The anterior ocular segment observation optical system includes light sources 35 a and 35 b that emit infrared light, an objective lens 25, and an anterior ocular segment observation auxiliary lens 26 (hereinafter referred to as an auxiliary lens), from the perforated mirror 22 to the image sensor 38. This optical system is shared with the fundus observation optical system. The infrared light sources 35a and 35b are a pair of rectangular LED light sources symmetrically arranged with the photographing optical axis L1 in between, and a finite index (patient) by a divergent light beam at a predetermined projection angle toward the cornea of the eye E. A rectangular index extending in a direction perpendicular to the eye) is projected. That is, the entire anterior segment is illuminated by the light sources 35a and 35b, and the alignment state of the eye E and the imaging unit 3 in the three-dimensional direction is shown.

The auxiliary lens 26 is inserted into and removed from the optical path by driving of the driving means 26a. When the auxiliary lens 20 is placed on the optical axis L1, the anterior segment and the image sensor 38 are in a substantially conjugate relationship. That is, at the time of observing the anterior segment, the anterior segment captured by the image sensor 38 with the auxiliary lens 26 placed on the optical axis L1 is displayed on the monitor 8. On the other hand, at the time of fundus observation, the auxiliary lens 26 is retracted from the optical path by driving of the driving unit 26 a, the imaging element 38 and the fundus are in a substantially conjugate relationship, and the photographed fundus image is displayed on the monitor 8.
In the present embodiment, the point light source 27 is provided in the vicinity of the aperture of the perforated mirror (substantially conjugate position of the fundus), and the working light W formed on the fundus is formed by turning on the point light source 27 during fundus observation. Alignment in the working distance direction is performed.

<Focus Index Projection Optical System> The focus index projection optical system 40 is provided obliquely on the optical path of the infrared light source 41, the slit index plate 42, the two declination prisms 43 attached to the slit index plate 42, and the illumination optical system 10. Lever 45, spot mirror 44 attached to lever 45 and placed at the conjugate position of the fundus, rotary solenoid 46, and projection lens 47.
The lever 45 is placed on the optical axis, and the spot mirror 44 is attached to the tip of the lever 45 so as to be placed at a position avoiding the optical axis. As a result, during observation of the fundus, the reflected light from the spot mirror 44 is projected to a position on the fundus that avoids the optical axis L1.

  The light flux of the slit indicator plate 42 is separated by the declination prism 43, reflected by the spot mirror 44 via the projection lens 47, and projected onto the fundus via the relay lens 21, the perforated mirror 22 and the objective lens 25. . When the fundus is out of focus, the index images (focus indices S1, S2) on the slit index plate 42 are not conjugated to the fundus and are projected separately on the fundus. In this case, the focusing lens 32 and the focus target projection optical system 40 are moved in the optical axis direction in conjunction with the drive of the drive mechanism 49 based on the detection result of the separation state of the focus targets S1 and S2. On the other hand, when the fundus is in focus, the focus indices S1 and S2 are in conjugate positions with the fundus. When fundus photographing is performed in a focused state, the lever 45 is retracted from the optical path by the rotation of the shaft of the rotary solenoid 46.

<Target Presentation Optical System> The target presentation optical system 70 has a target presentation unit 100 that presents a fixation target and a test target to the patient's eye, and is flipped up from the objective lens 25 of the observation / photographing optical system 30. Share up to 34. A known configuration described in, for example, Japanese Patent Application Laid-Open No. 2003-172974 is applied to the optotype presenting unit 100.
FIG. 3 shows an example of the optotype presenting unit 100. The optotype presenting unit 100 includes a light source 101, wavelength selection mirrors 102 and 103 as spectroscopic means, reflection mirrors 104 to 106, liquid crystal panels 110 to 112, a cross dichroic prism 120, and a beam splitter 130 for branching an optical path. As the light source 101, a white LED light source is used. In addition to this, a known thermal radiation light source such as a halogen lamp, a laser light source, or the like can be used as the light source 101.

The wavelength selection mirror 102 has a characteristic of reflecting a light beam in a red wavelength band and transmitting a light beam in another wavelength band. The wavelength mirror 103 has a characteristic of reflecting a light flux in the green wavelength band and transmitting a light flux in other wavelength bands. The reflection mirror 104 reflects the remaining light flux in the blue wavelength band. The liquid crystal panel 110 is illuminated with a red light beam reflected by the mirror 102. The liquid crystal panel 111 is illuminated with a green light beam reflected by the mirror 103. The liquid crystal panel 112 is illuminated with a blue light beam reflected by the mirror 104. Thereby, an image for each RGB is formed by each of the liquid crystal panels 110 to 112. That is, a red image is formed by driving the pixels of the liquid crystal panel 110, a green image is formed by driving the pixels of the liquid crystal panel 111, and a blue image is formed by driving the pixels of the liquid crystal panel 112.
The cross dichroic prism 120 makes the light beams transmitted through the liquid crystal panels 110 to 112 coaxial. As a result, the RGB images formed on the liquid crystal panels 110 to 112 are combined to form one image.

  In other words, inspection targets having different diameters can be formed by driving the pixels of the liquid crystal panels 110 to 112, and an inspection target having a size (size) corresponding to the inspection region is projected onto the fundus. Further, by adjusting the pixel transmittance and the like of each of the liquid crystal panels 110 to 112, it is possible to project an inspection target having an arbitrary color (having a wavelength band) on the fundus. As a result, it is possible to project an inspection target in a wavelength band corresponding to the type of photoreceptor cell (cone or rod) to be inspected on the fundus.

  <Control System> The control unit 80 is connected to the above-described optical system and control system and performs various operation controls. The control unit 80 is connected with a memory 83 as a storage unit, and stores information such as various programs in advance. The memory 83 stores cell density change information relating to the visual function of the human eye and information on the projection diameter (size) of the test visual target acquired in advance in association with the presentation position of the test visual target. For example, information relating to the projection diameter of the inspection target is stored so that the diameter of the inspection target is determined according to the radial distance of the inspection target relative to the fixation target.

Accordingly, the control unit 80 determines the fixation target from the coordinates of the fixation target (the coordinates of the liquid crystal panels 110 to 112) acquired from the target presentation unit 100 and the coordinates of the inspection target (the coordinates of the liquid crystal panels 110 to 112). The radial distance of the inspection target with respect to is obtained. Then, based on the information regarding the projection diameter of the inspection target stored in the memory 83, the projection diameter of the inspection target is set according to the approach state between the fixation target and the inspection target. Specifically, as the distance between the fixation target and the inspection target increases, the diameter of the inspection target projected onto the fundus is set larger.
Cells related to visual function include ganglion cells, photoreceptor cells, and the like. Hereinafter, an example in which a visual function test based on the number (density) of photoreceptor cells is performed will be described.

  FIG. 4 shows an example of photoreceptor cell density distribution (change information). FIG. 4 was calculated based on the equation (1) modeled in the literature (A Photo Accurate Model of the Human Eye OCT.2.2005 Micheal F. Deering).

式（１）において、Ｒ［cones/mm2］は単位平方mmに含まれる視細胞（錐体細胞）密度であり、θは黄斑部（原点）からの離心率［rad］である。図４ではθ＝０．１［rad］で規格化したグラフを示している。なお図中において縦軸が視細胞密度Ｒ[comes/mm2]、横軸が離心率θ［rad］である。つまり図４から眼底中心部（黄斑部）からのラジアル方向の距離（離心率θ）が大きくなる（周辺部に到る）に伴い、視細胞（錐体細胞）密度が低下することが分かる。

In equation (1), R [cones / mm2] is the density of photoreceptor cells (cone cells) contained in the unit square mm, and θ is the eccentricity [rad] from the macula (origin). FIG. 4 shows a graph normalized by θ = 0.1 [rad]. In the figure, the vertical axis represents the photoreceptor density R [comes / mm2], and the horizontal axis represents the eccentricity θ [rad]. That is, it can be seen from FIG. 4 that the density of photoreceptor cells (cone cells) decreases as the radial distance (eccentricity θ) from the center of the fundus (macular region) increases (goes to the periphery).

  The control unit 80 changes the size of the examination target according to the examination site of the fundus based on the change information of the photoreceptor cell density. For example, the reciprocal of the decrease rate (change rate) of the change information of the photoreceptor cell density shown in FIG. 4 is obtained, and the diameter of the inspection target is set large in proportion to the reciprocal of the decrease rate. In this way, the influence of the difference in photoreceptor cell density between the fundus central part and the peripheral part is removed, and detection of a local threshold value change is suitably performed. In particular, a decrease in visual function due to deterioration of ganglion cells is suitably detected at the center of the fundus where the photoreceptor cells are dense.

  In other words, in the prior art, the inspection target of the same size is projected onto the fundus regardless of the characteristic that the photoreceptor density of the human eye is dense at the center of the retina and sparse at the periphery as shown in FIG. Therefore, the number of photoreceptor cells with respect to the examination target varies depending on the examination site of the fundus. That is, the density of photoreceptor cells decreases in the peripheral area, and the overlap between the receptive fields of each photoreceptor cell becomes sparse, and the probability that a test target of the same size can stimulate the photoreceptor cell field is reduced. On the other hand, since the density of photoreceptor cells increases in the central part, it may be difficult to detect even if a decrease in visual function due to deterioration of ganglion cells occurs.

  Therefore, in the present invention, the target size for visual field inspection is normalized according to the rate of change in the photoreceptor cell distribution density, and the visual function characteristics are evaluated by measuring the retinal sensitivity characteristics of the examination area under the flattened condition. To do. This facilitates detection of a minute sensitivity change in the local region of the fundus. In the present invention, since the inspection result at each inspection position is quantified, it is possible to extract a portion where the visual function is relatively lowered by one inspection.

Next, the operation of the fundus imaging apparatus having the above configuration will be described.
The apparatus is activated, the patient's face is brought close to the apparatus 1, the imaging eye (patient eye E) is aligned with the imaging window 9, the inside of the apparatus is looked into, and then alignment (alignment) using the anterior segment image is performed. Start. When the driving unit 26a is driven by the control unit 80, the anterior ocular segment observation auxiliary lens 26 is placed on the optical axis L1, and when the light sources 35a and 35b are turned on, the anterior segment of the patient's eye E is illuminated and aligned on the cornea. A mark is projected. Further, the control unit 80 causes the patient eye E to present the fixation target with the optotype presenting unit 100. Specifically, the control unit 80 drives the pixels of each of the liquid crystal panels 110 to 112 with the light source 101 turned on, and the light beam transmitted through each of the liquid crystal panels 110 to 112 is fixed at a position corresponding to the optical axis L2. Form a target.

  When the eye E is guided by a fixation target, an anterior segment image appears on the monitor 8. FIG. 5 shows an example of an anterior segment image displayed on the monitor 8. In FIG. 5, rectangular alignment targets M <b> 1 and M <b> 2 appear in the anterior segment image F <b> 1 captured by the image sensor 38. The controller 80 aligns the imaging unit 3 and the patient's eye E based on the light reception results of the alignment targets M1 and M2.

  The control unit 80 drives the driving unit 6 so that the intermediate position obtained from the alignment index images M1 and M2 imaged by the image sensor 38 and the pupil center obtained from the anterior eye image detected by the image sensor 38 coincide. Then, the entire photographing unit 3 is moved in the up / down / left / right (XY) directions. Further, the driving unit 6 moves the photographing unit 3 in the front-rear (Z) direction with respect to the eye E so that the alignment targets M1 and M2 are at a predetermined interval. For a detailed description of the alignment operation of this embodiment, refer to International Publication No. 2008/062527.

When the alignment in the three-dimensional direction falls within the allowable range, focusing on the fundus is started. The control unit 80 turns off the light sources 35a and 35b, drives the driving unit 22a to retract the anterior ocular segment observation auxiliary lens 22 from the optical path, and turns on the light source 11.
6A and 6B are examples of a fundus image displayed on the monitor 8. FIG. 6A shows a state where the fundus is not focused, and FIG. 6B shows a state where the fundus is focused. . The control unit 80 specifies the positions of the focus indexes S1 and S2 based on the luminance distribution of the imaging range of the image sensor 38, obtains the distance (separation state) between the detected focus indexes S1 and S2, and based on the detection result. Adjust the focus.

When the focus is not achieved as shown in FIG. 6A, the control unit 80 moves the focusing lens 32 on the optical axis L1 so that the focus targets S1 and S2 are matched. When the control unit 80 determines that the focus is appropriate, the focus adjustment is completed.
When the fundus image F2 is clearly displayed on the monitor 8, the control unit 80 corrects the positional deviation between the eye E and the photographing unit 3 (optical axis L1) caused by the movement and rotation of the eye E that occurs during visual field measurement. The tracking for correcting the positional deviation of the presented visual target is performed. Refer to Japanese Patent Application Laid-Open No. 2011-255045 for a detailed description of auto alignment and tracking.

Next, the control unit 80 causes the eye E to present the visual field inspection target according to the visual field measurement program stored in the memory 83 in advance. For example, the presentation position of the visual field inspection target is set manually by the examiner, and the control unit 80 automatically switches according to a program (order) stored in advance in the memory 83.
For example, when the test target presentation position is manually set, the control unit 80 obtains the selected test target presentation position (coordinates) based on the input signal from the control unit 7a. Then, a visual target presentation is performed so as to form an inspection visual target having a predetermined projection diameter (size) with respect to the selected presentation position (coordinates) by performing change information on the visual cell density stored in the memory 83 or a predetermined calculation. The drive of the unit 100 is controlled.

  Similar to the fixation target presentation method described above, the control unit 80 controls the driving of the pixels of each of the liquid crystal panels 110 to 112 in accordance with the presentation position of the test target, and the transmitted light corresponds to the photoreceptor cell density. The test target of the size of the period is presented. Further, the luminance of the visual field inspection target (in other words, contrast with the background luminance) is changed in a predetermined step by controlling the output of the light source 101 or the pixels of the liquid crystal panels 110 to 112 (for example, 1 dB step).

Here, as shown in the schematic diagram of the inspection target projected onto the fundus in FIG. 7, the projection diameter D of the visual field inspection target is, for example, D = d1 at the center of the fundus (macular region) M, and the peripheral portion. As it goes away in the radial direction, the diameter D = d2 is set at a position p2 at a distance w2 from the macula M, and the diameter D = d3 is set to be gradually increased at a position p3 at a distance w3 from the macula M. Are stored in the memory 83. Note that distance w2 < w3 and diameter d1 < d2 < d3.
Note that a graphic of the inspection target may be displayed on the monitor 8 in order to easily show the size of the inspection target to the examiner.

  By the drive control of the visual target presenting unit 100 as described above, the presentation position of the visual inspection target is randomly switched and the luminance of the visual inspection target is changed. At this time, the patient presses the response button 7b when recognizing the visual field inspection target while maintaining fixation with the fixation target. Based on the input signal, the control unit 80 stores the luminance of the visual field inspection target at that time in the memory 83 as response information of the sensitivity that the patient can recognize at the measurement point. On the other hand, when there is no input of the response button 7b for the visual field inspection target, the luminance of the visual field inspection target at that time is stored in the memory 83 as response information of sensitivity that cannot be recognized by the patient at the measurement point.

  In this embodiment, since the projection diameter D of the test target is changed according to the examination site of the fundus, the dependence on the change in the photoreceptor cell density is removed, and the state closer to normalization (flattened state) A visual field inspection result can be obtained. Therefore, the examiner can easily obtain the local sensitivity change of the fundus by comparing the test result of the entire fundus and the test result of the local region.

  When the visual field inspection is completed at all measurement points, the control unit 80 causes the monitor 8 to display the distribution state of the sensitivity threshold value of the fundus visual field. FIG. 8 shows an example of the inspection result of the visual field sensitivity distribution. The examiner confirms the inspection result of the entire retina from the distribution state of the visual field sensitivity displayed on the monitor 8. At this time, in this embodiment, the visual function is evaluated based on the same determination criterion regardless of the examination site of the fundus. In other words, even if the threshold value of the visual field sensitivity is the same in the prior art, since the test result includes a difference depending on the number of photoreceptor cells, it is not the true sensitivity of each part. On the other hand, in the present invention, by removing the influence due to the change in the photoreceptor cell density, the examiner can grasp the difference in local sensitivity change based on the measurement result (numerical value) of the visual field sensitivity displayed on the monitor 8. ing.

  In the above description, an example is shown in which the examiner's manual display position of the test target is selected. On the other hand, also when the test target is automatically switched and presented, the control unit 80 calls information on the test target stored in the memory 83 according to the distance (coordinates) from the macular part of the presented target. Thus, it is possible to present an inspection target having a desired size according to the position of the inspection target.

  Note that photoreceptor cell density change information may be input for each patient. In this case, input means for inputting the visual function density distribution is provided in the fundus examination apparatus. For example, a known medium such as USB or LAN is used as the input means. On the other hand, photoreceptor cell density information acquired for each patient is obtained by, for example, a fundus photographing image photographed by a fundus photographing apparatus having a wavefront compensation unit for removing aberrations of a patient's eye and capable of photographing the fundus at a high magnification of a cell level. It is calculated using.

  With the above configuration, the control unit 80 causes the memory 83 to store the change information of the photoreceptor cell density for each patient (or an approximation of the reciprocal change rate of the decrease rate of photoreceptor cells in the fundus) input from the input unit. When the visual field inspection is performed, the size of the stimulus target to be projected onto the fundus central part and the peripheral part of the patient's eye is set based on the photoreceptor cell density change information input for each patient. In this way, more accurate test results can be obtained for each patient.

  Further, the change information of the photoreceptor cell density may be held for each photoreceptor cell type. For example, information on changes in photoreceptor cell density of cone cells and rod cells is stored in the memory 83. When inspecting the sensitivity (retinal sensitivity) of the pyramidal cells, the luminance of the visual target presenting unit 100 is set so that the background luminance becomes a light-adapted environment, and the size of the visual inspection target is set to the cone cell distribution density. The rate of change is changed according to the reciprocal model curve. When inspecting the retinal sensitivity of rod cells, the luminance of the target presentation unit 100 is set so that the background luminance becomes a dark adaptation environment, and the size of the inspection target is the reciprocal model curve of the rate of change of rod cell density distribution. Change according to. In this way, improvement in visual function inspection accuracy according to the type of photoreceptor cell is expected.

  Note that the change in the projected diameter of the inspection target based on the change information of the photoreceptor cell density may be changed in at least two stages. For example, as shown in FIG. 9, in a range D1 where the distance from the macular portion M is closer than the distance threshold value wp, an inspection target having a diameter d1 is projected, and the distance from the macular portion M is larger than the distance threshold value wp. However, an inspection visual target having a diameter d2 may be presented in the farther range D2 (diameter d1 <d2).

  Further, in the above, the diameter of the inspection target is changed based on the change information of the photoreceptor density so that the projection condition of the inspection target on the photoreceptor is constant. In addition to this, it is also possible to change the density of the inspection target without changing the diameter of the inspection target so that the projection condition of the inspection target is constant between the central portion and the peripheral portion of the fundus. For example, in this embodiment, the density of the inspection target can be changed by switching the pixels of the liquid crystal panels 110 to 112 on and off. For example, as shown in the schematic diagram of FIG. 10, in the vicinity of the macular portion M, pixels that form the test target having a diameter d <b> 1 are turned OFF in a predetermined step, so that the photoreceptor cells stimulated by the test target are turned off. Limit the number. On the other hand, in the part away from the macular part M, the number of photoreceptor cells that are stimulated by the examination target is increased by increasing the number of pixels that are turned on in each pixel as compared with the central part of the macula. This makes it possible to make the stimulation conditions for the photoreceptor cells constant at the center and the peripheral part of the fundus.

  Furthermore, in the above description, an example in which the threshold value of a photoreceptor cell is obtained as a cell related to visual function has been described. By changing the projected diameter of the inspection target to be performed, the visual function characteristics can be evaluated in a state where the influence of the difference in the number of cells is suppressed.

It is an external appearance block diagram of a fundus inspection apparatus. It is explanatory drawing of the optical system and control system of a fundus examination apparatus. It is an example of a target presentation part. It is an example of photoreceptor density distribution (change information). An example of an anterior segment image displayed on a monitor is shown. It is an example of the fundus oculi image displayed on the monitor. It is a schematic diagram of the test | inspection target projected on a fundus. It is an example of the inspection result of visual field sensitivity distribution. It is an example of a change of the projection pattern of an inspection target. It is an example of a change of the projection pattern of an inspection target.

DESCRIPTION OF SYMBOLS 1 Fundus examination apparatus 8 Monitor 10 Illumination optical system 30 Observation / photographing optical system 40 Focus index projection optical system 70 Target presentation optical system 80 Control unit 83 Memory 100 Target presentation unit 110, 111, 112 Liquid crystal panel

Claims (2)

A fundus examination apparatus that inspects the fundus by projecting an examination target on the examination position of the fundus of the subject eye,
Fixation target forming means for forming a fixation target to be presented and guided to the eye to be examined;
An inspection target setting means for setting an inspection position by an inspection target for the fundus of the eye to be examined ;
A target projecting means capable of projecting the test target on the test position of the fundus of the eye corresponding to the test position set by the test target setting unit;
The distance in the radial direction of the inspection target relative to the fixation target based on the coordinates of the fixation target formed by the fixation target forming unit and the coordinates of the inspection target set by the inspection target setting unit And a control means for controlling the target projection means so that a projection diameter of the inspection target that is relatively far from a projection diameter of the inspection target that is relatively close to the radial direction is large. ,
A fundus examination apparatus comprising: The fundus examination apparatus according to claim 1,
The inspection target setting means is further a fundus inspection apparatus that sets projection conditions of the inspection target according to the cell type relating to the inspection position and visual function on the fundus.

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