JP2013027672A - Fundus photography device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fundus photography device for performing focusing without having an examinee recognize a focus index.SOLUTION: The fundus photography device includes: an illumination optical system provided with an infrared light source for illuminating the fundus with infrared light; an imaging element having sensitivity to an infrared region; a visual target presentation optical system provided with a visual target presentation part for presenting a visible visual target to the fundus; a focus chart for forming a focus visual target of a prescribed shape on the fundus by shielding a part of the infrared light directing toward the eye in the irradiation optical path of the infrared light of the illumination optical system; a focusing lens which interlocks with the focus chart and moves to an optical axis; a focus adjustment means for performing focusing on the basis of brightness information about the focus index projected on the fundus; and a visible light illumination means for superimposing the illumination light by visible light on a position of the focus index formation on the fundus so as not to have the examinee perceive the focus index projected on the fundus when performing focusing by the focus adjustment means.

Description

  The present invention relates to a fundus imaging apparatus for observing and photographing the fundus of a subject's eye.

  A conventional fundus imaging apparatus causes a visual target such as a fixation target to be presented to a subject's eye with visible light using a visual target presentation unit such as a liquid crystal display. Further, fundus observation is performed by illuminating the fundus of a subject's eye with infrared light and photographing the fundus with an imaging element having sensitivity in the infrared region. Further, in order to perform focusing between the fundus and the photographing apparatus, there is known one using a focus index formed by shielding a part of infrared light from the infrared light source (for example, a patent). Reference 1).

International Publication No. 2008/062527

  However, when the center wavelength of the infrared light emitted from the infrared light source is longer than 900 nm, the light receiving sensitivity of the image sensor is low, and it is difficult to perform accurate detection. On the other hand, when using light in the near infrared region of about 700 nm or more and 900 nm or less, the required light receiving sensitivity of the image sensor can be obtained, but depending on the subject, illumination light in the near infrared region is perceived. The focus index may be recognized by the subject. As described above, when the focus target is recognized by the subject, the eye's adjustment force works, and it may be difficult to perform fundus photography and various examinations in an appropriate state.

  In view of the above-described problems of the prior art, the present invention provides a fundus imaging apparatus that can perform fundus imaging and various examinations in an appropriate state without the subject being aware of the focus index. To do.

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

(1) An illumination optical system including an infrared light source for illuminating the fundus of the subject's eye with infrared light, and sensitivity at least in the infrared region for photographing the fundus illuminated with the infrared light An imaging element, a target presentation optical system including a target presentation unit for presenting a visual target on the fundus, and a conjugate position with the fundus in the irradiation light path of the infrared light of the illumination optical system A focus chart that forms a focus target of a predetermined shape on the fundus by blocking a part of the infrared light directed to the eye of the subject, and in the optical axis direction in conjunction with the focus chart A focusing lens provided so as to be movable, and a focusing lens for moving the focusing lens based on luminance information of the focus index projected onto the fundus on the focus chart. In a fundus photographing apparatus comprising a focus adjusting means, a light source that emits light in the near-infrared region having a center wavelength of 700 nm to 900 nm as the infrared light source is used, and at the time of focusing by the focus adjusting means, In order to prevent the subject from perceiving the focus index projected onto the fundus, it is provided with visible light illumination means for superimposing illumination light by visible light on at least the focus index formation position on the fundus. Features.
(2) In the fundus imaging apparatus according to (1), the light amount of the visible light illumination unit that is turned on during the focusing is a light amount that does not cause a predetermined miosis in the subject's eye.
(3) In the fundus imaging apparatus according to (2), the focus chart transmits the visible light in the entire focus chart, blocks the infrared light in the focus index formation region, and transmits in the other region. It has the characteristic to make it have.
(4) The fundus imaging apparatus according to (3) includes a light flux limiting member for guiding only the infrared light of the infrared light and the visible light reflected from the fundus to the image sensor, and the light flux The focusing is performed by receiving the infrared light guided to the imaging element by a limiting member.
(5) In the fundus imaging apparatus according to (4), the visible light illuminating means is the optotype presenting unit.
(6) In the fundus imaging apparatus according to (5), the target presentation unit is a member for projecting a test target for performing a visual field test on the fundus of the subject's eye as the target. And
(7) In the fundus imaging apparatus according to (6), the target presentation unit is a liquid crystal display.

  According to the present invention, it is possible to provide a fundus imaging apparatus that can perform fundus imaging and various examinations in an appropriate state without the subject being aware of the focus index.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a fundus photographing apparatus having a function of measuring a visual field (visual sensitivity distribution) of a subject's eye and a function of observing and photographing the fundus will be described as an example.

  FIG. 1 is an external configuration diagram of a fundus imaging apparatus. The fundus imaging apparatus 1 is movable in a three-dimensional direction (XYZ direction) with respect to the base 1a, a movable base 2 provided so as to be movable in the horizontal direction (XZ direction) with respect to the base 1a. And a face support unit 5 provided on the base 1a for supporting the face of the subject. The imaging unit 3 accommodates an optical system to be described later, and is moved by an electric drive unit 6 provided on the movable table 2.

  On the examiner side of the imaging unit 3, a joystick 4, a control unit 7a, and a monitor 8 for moving the imaging unit 3 relative to the subject's eye E are provided. The joystick 4 is used to adjust the position of the movable table 2 and the photographing unit 3. When the joystick 4 is tilted, the movable table 2 slides horizontally on the base 1a by a sliding mechanism (not shown). Further, when the rotary knob (not shown in the figure) of the joystick 4 is rotated, the photographing unit 3 is moved in the vertical direction by the drive of the driving unit 6. The control unit 7a is used as input means for various inspection conditions. For the control unit 7a, a known configuration such as a mouse, a keyboard, and a touch panel is used. On the monitor 8, various examination screens are displayed, and a fundus image taken by the photographing unit 3 is displayed. An imaging window 9 and a response button 7b are provided on the subject side of the imaging unit 3. The photographing window 9 is used for a subject to look into the apparatus during the examination. The response button 7b is used by the subject to input a response signal during the visual field inspection.

  Next, the optical system and control system of the fundus imaging apparatus 1 will be described with reference to FIG. A fundus illumination optical system 10 for illuminating the fundus includes a light source 11 that emits infrared light, a light source 12 that emits visible flash light during fundus photography, a collimator lens 13, a total reflection mirror 14, a focus chart 15, and a condenser lens 16. A ring slit 17 having a ring-shaped opening, a relay lens 18, a perforated mirror 19, and an objective lens 21. Note that the light source 11 used in the present embodiment is a light source that emits near-infrared light having a center wavelength of 840 nm, but is not limited thereto. Any light source that emits light in the near infrared region of 700 nm to 900 nm may be used. In order to prevent the subject from perceiving infrared light, it is preferable to use a light source that emits infrared light as close to 900 nm as possible (long wavelength).

  The ring slit 17 is placed at a conjugate position with the pupil of the eye E via the relay lens 18. The focus chart 15 includes a filter 15a that transmits visible light and infrared light, and a focus index 15b that is formed on the filter 15a by a coating process having a characteristic of transmitting visible light and blocking infrared light. . FIG. 3 is an example of a focus chart. Here, a ring-shaped focus target 15b is formed on the filter 15a. In this embodiment, the ring-shaped focus target 15b is used. However, the present invention is not limited to this, and any shape that can be used as a focus index may be used.

  During observation of the fundus, the infrared light from the light source 11 illuminates the focus chart 15 from behind through the collimator lens 13 and the total reflection mirror 14. Infrared light that has passed through the filter 15a excluding the position where the focus target 15b is formed forms an image at the pupil of the eye E from the condenser lens 16 through the objective lens 21, thereby illuminating the fundus. On the other hand, a part of the infrared light is shielded at the position where the focus target 15b is formed, so that the dark target focus target 15b is projected on the fundus. The focus index 15b is suitably distinguished from a blood vessel or the like by being formed by a line having a width sufficiently thicker than the thickness of the blood vessel.

  Further, the visible light irradiated by turning on the light source 12 at the time of photographing the fundus follows the same optical path as the infrared light, and illuminates the fundus. Since the filter 15a and the focus target 15b transmit visible light, the fundus is uniformly illuminated by the visible light emitted from the light source 12 without forming a ring-shaped focus index. The focus chart 15 is moved on the optical axis together with the focusing lens 24 by the driving means 24a. Thus, focusing is performed using the focus index projected as a shadow on the fundus.

  The fundus oculi observation / imaging optical system 20 includes an objective lens 21, an imaging aperture 23, a focusing lens 24, a relay lens 25, a total reflection mirror 26, a relay lens 27, a beam splitter 33a as an optical branching member, an imaging lens 28, a two-dimensional image. An image sensor 29 is provided. The diaphragm 23 is placed in a conjugate position with the pupil via the objective lens 21. The focusing lens 24 is moved along the optical axis L2 together with the focusing chart 15 by the driving means 24a. The two-dimensional image sensor 29 is placed at a conjugate position with the fundus and has sensitivity in the wavelength band from infrared light to visible light. The beam splitter 33a as a light beam limiting member reflects infrared light (light source 11, light beams from infrared light sources 35a and 35b of the anterior ocular segment illumination optical system 30 described later), and visible light (light source 12; And has a characteristic of transmitting a light beam from the sign presentation optical system 40.

  Thereby, at the time of observation of the fundus, infrared light from the fundus and reflected light by visible light are incident on the beam splitter 33a from the objective lens 21 through the relay lens 27, so that visible light is transmitted and infrared light is transmitted. Is reflected. Thereby, focusing using the focus index is preferably performed by the infrared light received by the image sensor 29.

  The beam splitter 33a is switched to the beam splitter 33b having infrared light transmission / visible light reflection characteristics when photographing the fundus. Thereby, the reflected light from the fundus illuminated with visible light is suitably received by the image sensor 29 through the objective lens 21 to the imaging lens 18.

  In the above description, the single image sensor 29 is used to perform both fundus observation using infrared light and fundus photographing using visible light. In addition to this, a two-dimensional image sensor having sensitivity in the wavelength band of infrared light and a two-dimensional image sensor having sensitivity in the wavelength band of visible light are separately provided, and fundus observation using infrared light and visible light are used. The fundus photographing may be performed by a different image sensor.

  Further, in the above description, infrared light from the fundus and reflected light from visible light are branched by the beam splitter, so that infrared light is guided to the image sensor 29. In addition to this, infrared light is suitable for the image sensor 29 by providing a filter having a characteristic of transmitting infrared light and blocking visible light during observation of the fundus on the optical path of the fundus observation / imaging optical system 20. You may be made to guide to. On the other hand, in the case of providing such a filter, when photographing the fundus, the filter is retracted from the optical path using a known drive mechanism. As a result, visible light is received by the image sensor 29 and the fundus is photographed.

  The anterior ocular segment observation optical system 30 includes light sources 35 a and 35 b that emit infrared light, an objective lens 21, and an anterior ocular segment observation auxiliary lens 22, and the imaging element 29 from the perforated mirror 19 of the fundus oculi observation / imaging optical system 20. Share the optical system up to. The infrared light sources 35a and 35b are composed of a pair of rectangular LEDs arranged symmetrically with respect to the photographing optical axis L1. By projecting a finite index (a rectangular index extending in a direction perpendicular to the subject's eye) with a divergent light beam at a predetermined projection angle toward the cornea of the eye E, the eye E, the imaging unit 3, The alignment state in the three-dimensional direction is shown. In addition, the entire anterior segment is illuminated. The anterior ocular segment observation auxiliary lens 22 is disposed so as to be detachable with respect to the optical path by driving of the driving means 22a. At the time of observing the anterior ocular segment image by the anterior ocular segment observation optical system 30, the anterior ocular segment observation auxiliary lens 22 is placed on the optical axis L2 by driving of the driving means 22a comprising a motor or the like. 29 is a substantially conjugate relationship. On the other hand, at the time of fundus observation / photographing, the anterior ocular segment observation auxiliary lens 22 is removed from the optical path, so that the fundus and the image sensor 29 are in a substantially conjugate relationship.

  The optotype presenting optical system 40 shares the objective lens 21 to the relay lens 27 of the fundus oculi observation / photographing optical system 20, and is a well-known optotype presenting unit that forms a visual target with the imaging lens 42 and visible light. LCD display (hereinafter referred to as a display) 41. The display 41 is placed at a conjugate position with the fundus oculi, and the display state of various targets such as a fixation target and a visual field inspection target is controlled by the control unit 50 described later. Further, when focusing on the fundus, a predetermined area of the display 41 is lit with visible light, so that visible light is superimposed on the focus index projected onto the fundus so that the subject does not perceive the focus index. Various visual targets displayed on the display 41 pass through the imaging lens 42, the lens 27, the mirror 26, the lens 25, the focusing lens 24, and the perforated mirror 19, and then are projected onto the fundus through the objective lens 21.

  In this embodiment, the relay lenses 25 and 27 and the imaging lens 42 constitute a telecentric side. Thereby, the light beam irradiated from the display 41 is projected uniformly on the fundus of the subject's eye.

  In addition to the display described above, a known configuration that projects the target on the fundus with visible light is used as the target presentation unit. For example, a projector that forms various visual targets by two-dimensionally scanning laser light emitted from a visible laser light source on the fundus may be used.

  In the above description, the display for presenting various visual targets is used as the visible light illumination unit for preventing the subject from perceiving the shadow of the focus chart. However, the present invention is not limited to this. For example, a visible point light source with a sufficient divergence angle is provided on the pupil conjugate plane of the fundus observation / imaging optical system to illuminate a focus index formed by the shadow of infrared light projected on the fundus during focusing of the fundus You may do it. In addition to this, a visible light illuminator that can superimpose visible light on the focus index is placed in the optical path of the fundus observation / imaging optical system so that the focus index projected using the focus chart is not perceived by the subject. It should just be provided in.

  The control unit 50 controls the operation of the entire fundus imaging apparatus 1. For example, the control unit 50 detects an alignment index from the anterior segment image captured by the imaging element 29 when observing the anterior segment. Further, during observation of the fundus, the focus state of the fundus is detected from the focus index projected onto the fundus, and the focusing lens 24 is moved on the optical axis L2 by driving of the driving unit 24a. As a result, the focus of the fundus image captured by the image sensor 29 is adjusted. In addition, a memory 51 as a storage unit 51 is connected to the control unit 50. In the memory 51, various inspection conditions are stored in advance, and information on various inspection results is stored.

  By the way, in the fundus imaging apparatus 1 having the above-described configuration, the infrared light source 11 is assumed to have as high a light receiving sensitivity as possible in accordance with the infrared sensitivity characteristic of the known image sensor 29 from the viewpoint of detection accuracy. It is preferable to select one that emits light in the infrared region (near infrared). However, depending on the wavelength of the infrared light emitted from the infrared light source 11, the subject may perceive it, and as a result, the focus index may be recognized. In such a case, the subject's ability to adjust the eye works because the subject sees the focus index. In this way, the state where the adjustment force is acting on the eye is likely to fluctuate (is unstable), and there is a high possibility that the examination cannot be performed accurately. In addition, when performing fundus photographing, there is a high possibility that the accuracy of the photographed image is lowered.

  Therefore, in the present invention, a light source that emits light having an infrared wavelength (700 nm to 900 nm) as a central wavelength so that the light receiving sensitivity of the image sensor can be suitably obtained is used, and a focus index as a shadow is projected onto the fundus In this case, the entire display 41 (at least the projection area of the focus index) of the target presentation device 40 is uniformly lit with visible light so that the subject does not recognize the focus index. Furthermore, by performing such irradiation of visible light with a target display unit (LCD display in the present embodiment) that presents a fixation target or a target for visual field inspection, a new ophthalmic photographing apparatus of the prior art is added. Without adding a configuration, the fundus is more suitably focused, and various photographing and inspection can be performed more accurately.

  Note that the visible light of the display 41 at this time is a light amount that does not cause a predetermined miosis in the subject's eye, and is set to a light amount that does not recognize a focus index projected as a shadow. The predetermined miosis in the present embodiment is a state in which a fundus image with a predetermined accuracy cannot be obtained due to a lack of the amount of light incident on the pupil of the subject's eye, and a predetermined examination target is projected onto the fundus This indicates that the pupil is mitochonded to such an extent that various photographing and examinations using the fundus photographing apparatus 1 cannot be performed with a predetermined accuracy, such as a state where it becomes impossible or a flare is extremely likely to occur.

  In this embodiment, the entire display 41 is lit uniformly, but it is sufficient to irradiate the focus index with visible light so that the subject does not recognize the focus index projected on the fundus, For example, only a predetermined area of the display 41 corresponding to the projection position of the focus index on the fundus may be lit uniformly with visible light. Alternatively, only a predetermined area of the display 41 corresponding to the projection position of the focus index may be turned on with a relatively large amount of light, and the display 41 may be turned on so as to reduce the surrounding light amount. However, in this case, a predetermined miosis is not generated in the subject's eye by visible light irradiated from the entire display 41.

  Next, the operation of the fundus imaging apparatus having the above configuration will be described. Here, an example will be described in which the visual field inspection is performed by the response of the subject after the fundus is focused. First, the subject's face is brought close to the apparatus and the inside of the apparatus is looked through the photographing window 9. As a result, the eye E is photographed by the image sensor 29. First, alignment (alignment) between the apparatus using the anterior segment image and the eye E is performed.

  The controller 50 drives the driving means 22a to position the anterior ocular segment observation auxiliary lens 22 on the optical axis L2 and turn on the light sources 35a and 35b. Thereby, the anterior segment of the eye E is illuminated and a rectangular alignment index is projected on the cornea. Further, the control unit 50 turns on the center position of the display 41 corresponding to the optical axis L2 (here, it is assumed to be turned on in a cross shape). The light flux from the display 41 is projected onto the fundus through the imaging lens 42, the beam splitter 33, and the relay lens 27 through the objective lens 21. The examiner instructs the subject to look at the fixation target.

  FIG. 4 shows an example of the anterior segment image A displayed on the monitor 8. When rectangular alignment indexes M1 and M2 formed by the light sources 35a and 35b appear on the anterior segment image A captured by the image sensor 29, the control unit 50 captures images based on the light reception results of the alignment indexes M1 and M2. Positioning (alignment) between the unit 3 and the eye E is performed. The control unit 50 controls the drive of the drive unit 6 so that the intermediate position between the alignment indices M1 and M2 and the pupil center obtained from the anterior segment image A coincide with each other so that the imaging unit 3 is moved toward the eye E. To move up, down, left and right (XY). In addition, the control unit 50 performs alignment by moving the imaging unit 3 in the front-rear (Z) direction with respect to the eye E so that the interval between the alignment indexes M1 and M2 is a predetermined interval.

  When the alignment in the three-dimensional direction is within the allowable range, the control unit 50 determines completion of the alignment. Then, focusing of the fundus is started. The control unit 50 turns off the light sources 35a and 35b, and retracts the anterior ocular segment observation auxiliary lens 22 from the optical path L2 by driving the driving unit 22a. Then, the infrared light source 11 is turned on. Thereby, infrared light passes through the focus chart 15 and is projected onto the fundus. On the other hand, a part of the infrared light is shielded at the position of the focus index 15b, so that a ring-shaped focus index as a shadow is formed on the fundus. On the other hand, the control unit 50 superimposes visible light on the focus index projected on the fundus by lighting the entire display 41 with a uniform light amount so that the subject does not perceive the focus index projected on the fundus. I will let you. As described above, the light amount of the display 41 is a light amount that does not cause the subject to have a predetermined miosis, and is a light amount that the focus index projected as a shadow is not recognized by the subject. Thus, the focus index is prevented from being recognized by the subject while suppressing miosis due to stimulation of the fundus (retinal) by visible light. On the other hand, in order to present a fixation target to the subject's eye, the control unit 50 lights the center of the display 41 (a position corresponding to the optical axis L2) with an amount of light that can be recognized by the subject. Thus, the subject recognizes only the fixation target presented on the display 41.

  Reflected light (infrared light and reflected light) from the fundus enters the beam splitter 33a from the objective lens 21 through the relay lens 27. Since the beam splitter 33a has the characteristics of visible light transmission and infrared light reflection, the visible light component of the reflected light from the fundus is transmitted and only the infrared light component is reflected and imaged by the imaging device 29. . As a result, fundus observation and focusing are performed by infrared light received by the image sensor 29.

  FIG. 5 shows an example of a fundus image displayed on the monitor 8. Here, a state in which the focus target R, the fundus image F, and the fixation target T appear on the monitor 8 is shown. The control unit 50 performs focusing by controlling the driving unit 24a so that the focus index R is in focus (so that the width of the index R is the narrowest) from the light receiving state of the focus index R detected by the image sensor 29. The lens 24 is moved.

  In addition, when the focus index R is in a state perceived by the subject at the time of focusing, the subject can recognize the focus index R so that the focus adjustment in a state in which the eye's adjustment force is applied can be performed. As a result, accurate fundus photographing and various examinations cannot be performed. On the other hand, in the present embodiment, visible light is superimposed on the focus index R by turning on the display 41. As a result, the focus index R is not perceived by the subject and can be focused with high accuracy.

  Next, in order to perform the visual field inspection, tracking is set to correct the deviation of the presentation position of the target on the fundus caused by the rotation of the eye while the fundus image F is clearly visible. Thereby, even if the eye rotates during the examination, the visual function at each part of the fundus can be correctly recorded.

  For detailed description of the alignment operation, focusing, and tracking as described above, refer to International Publication No. 2008/062527.

  Next, the control unit 50 retracts the focus chart from the optical path using a driving unit (not shown), and uniformly illuminates the fundus with infrared light from the light source 11. That is, since focusing is not performed at the time of visual field inspection, the entire fundus image is displayed on the monitor 8 without forming a focus index. Further, the fixation target is turned on in a state where the entire display 41 is turned on with a predetermined luminance value serving as a reference on the perimeter side. Then, in accordance with the visual field measurement program stored in the memory 51 in advance, the control unit 50 sequentially changes the presentation position of the examination target by the drive control of the display 41 and changes the luminance value. In addition, the presentation position and luminance value of the inspection target may be set by an operator's manual operation.

  The subject presses the response button 7b after recognizing the examination target while maintaining the fixation. Based on the input signal from the response button 7b, the control unit 50 stores the luminance value of the test target at that time in the memory 51 as response information of sensitivity that can be recognized by the subject at the measurement point. On the other hand, when the subject does not respond to the presented target, the luminance value of the test target at that time is stored in the memory 51 as response information of unrecognizable sensitivity at the measurement point.

  When the measurement of sensitivity at all measurement points is completed, the control unit 50 causes the monitor 8 to display the distribution of sensitivity at all measurement points in association with the fundus image as shown in FIG. The visual field inspection result is obtained based on the difference between the background luminance of the display 41 and the luminance of the presented visual target. For example, the retinal sensitivity S at each measurement site of the fundus can be obtained based on, for example, the well-known arithmetic expression (1).

なお、式（１）において、Ｌmaxはディスプレイの最大輝度、Ｌｔは被検者が認識可能な輝度値（閾値）、Ｌｂはディスプレイの背景輝度である。
以上のようにすることで、眼底撮影装置と眼Ｅとのフォーカス合わせをより簡単な構成で精度良く行えるようになる。これにより、鮮明な眼底撮影像を好適に得ることが出来ると共に、各種検査をより正確に行えるようになる。

In Equation (1), Lmax is the maximum luminance of the display, Lt is a luminance value (threshold) that can be recognized by the subject, and Lb is the background luminance of the display.
By doing as described above, the fundus photographing apparatus and the eye E can be accurately focused with a simpler configuration. As a result, a clear fundus image can be suitably obtained and various inspections can be performed more accurately.

  The present invention is not limited to the above configuration. A focus index presenting optical system for projecting a focus index as a shadow formed by shielding part of infrared light from an infrared light source onto the fundus, and a visible light illuminating unit for illuminating visible light on the fundus The configuration of the present invention can be applied to a fundus photographing apparatus provided.

  For example, the configuration of the present invention in a combined machine of a laser treatment apparatus and a fundus photographing apparatus that performs treatment by photocoagulation by irradiating the fundus with a therapeutic laser beam while observing a fundus image observed by a fundus photographing optical system Is applicable. In addition, the above-described imaging apparatus that can observe a fundus image at a cell level by two-dimensionally scanning the fundus with the laser light as illumination light condensed on the observation surface of the fundus The configuration of the present invention can be applied to such a multifunction machine with the fundus imaging apparatus. Furthermore, the configuration of the present invention is applied to a combined machine of an imaging apparatus and an ocular fundus imaging apparatus that performs optical cross-sectional image imaging of a subject's eye by optical coherence tomography (OCT) using spectral interference. Focusing can be performed with high accuracy with a simple configuration, and various examinations can be suitably performed in addition to fundus observation and imaging.

It is an external appearance block diagram of a fundus imaging apparatus. It is explanatory drawing of the optical system and control system of a fundus imaging apparatus. It is an example of a focus chart. It is an example of the anterior segment image displayed on a monitor. It is an example of the fundus oculi image displayed on the monitor. It is an example of the measurement result of the retinal sensitivity displayed on a monitor.

DESCRIPTION OF SYMBOLS 1 Fundus photographing apparatus 10 Fundus illumination optical system 11 Infrared light source 15 Focus chart 24 Focusing lens 24a Driving means 33a, 33b Beam splitter 40 Visual target presentation optical system 41 LCD display 50 Control unit

Claims (7)

An illumination optical system including an infrared light source for illuminating the fundus of the subject's eye with infrared light;
An image sensor having sensitivity at least in the infrared region for photographing the fundus illuminated with the infrared light;
An optotype presenting optical system comprising an optotype presenting unit for presenting a visible optotype on the fundus;
In the irradiation optical path of the infrared light of the illumination optical system and placed in a conjugate position with the fundus, by blocking a part of the infrared light toward the subject's eye, the fundus has a predetermined shape A focus chart that forms a focus target, and a focusing lens that is provided so as to be movable in the optical axis direction in conjunction with the focus chart. The brightness of the focus index projected onto the fundus using the focus chart A focus adjusting means for moving the focusing lens based on the information to perform focusing;
A fundus photographing apparatus comprising:
A light source that emits near-infrared light having a center wavelength of 700 nm to 900 nm as the infrared light source is used.
Further, in order to prevent the subject from perceiving the focus index projected onto the fundus during focus adjustment by the focus adjusting means, at least the focus index formation position on the fundus is illuminated with visible light. A fundus photographing apparatus comprising: visible light illuminating means for superimposing the light. The fundus imaging apparatus according to claim 1,
The fundus imaging apparatus according to claim 1, wherein the amount of light of the visible light illuminating means that is turned on during the focusing is an amount of light that does not cause a predetermined miosis in the subject's eye. The fundus photographing apparatus according to claim 2,
The focus chart has a characteristic that allows the visible light to pass through the entire area of the focus chart, and shields the infrared light from the focus index formation region and allows the infrared light to pass through other regions. . The fundus imaging apparatus according to claim 3 comprises:
Of the infrared light and the visible light reflected from the fundus, there is provided a light flux limiting member for guiding only the infrared light to the imaging device, and the red light guided to the imaging device by the light flux limiting member A fundus photographing apparatus that performs the focusing by receiving external light. The fundus imaging apparatus according to claim 4,
The fundus imaging apparatus, wherein the visible light illuminating means is the optotype presenting unit. The fundus imaging apparatus according to claim 5, wherein
The fundus imaging apparatus, wherein the target presentation unit is a member for projecting an inspection target for performing a visual field inspection on the fundus of a subject's eye as the target. The fundus imaging apparatus according to claim 6, wherein
The fundus photographing apparatus, wherein the target presentation unit is a liquid crystal display.

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