JPH10295645A - Eye ground photographing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an eyeground photographing device which can perform simple and accurate photographing of an afront eyeground portion and can produce an eyeground image vivid over the whole area. SOLUTION: An eyeground photographing device is configured so that the view line of the eye examined 1 is directed obliquely by allowing the subject to watch a fix watch light. In this condition, the X-Y alignment is made so that the photographing optical axis 4 of an eyeground photographing optical system passes the apex of the eye 1, and then an alignment correcting operation in the X-direction is conducted so that the optical-axis 4 passes the center of the pupil. The alignment correcting operation is performed by an X-direction corrective value sensing circuit 58 which senses the corrective value corresponding to the light-up position of the fix watch light out of a previously prepared look-up table and the second driving mechanism which moves the machine frame 3 of the eyeground photographing device in the X-direction for a certain distance on the basis of the signal given by the sensing circuit 58.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a fundus photographing apparatus. More specifically, the present invention relates to a fundus photographing apparatus capable of photographing a desired portion of the fundus.

[0002]

2. Description of the Related Art When photographing a fundus, an alignment operation for automatically or manually aligning the optical axis of the fundus photographing apparatus with the optical axis of the eye to be inspected, and the optical pupil of the fundus photographing apparatus coincides with the pupil of the eye to be examined. It is necessary to perform a working distance adjustment operation and a focusing operation to be performed. Conventionally, a fundus photographing apparatus disclosed in Japanese Patent Application Laid-Open No. 8-275921 is known as a fundus photographing apparatus that automatically performs such an operation.

In the alignment operation of this fundus photographing apparatus, first, the subject is fixed by fixing the subject's eye by staring a predetermined fixation lamp, and a parallel light (alignment index) is applied to the front eye of the subject's eye from the front. Light) and aligning the optical axis with the center of the cornea based on the Purkinje image as a corneal reflection image. Further, the working distance adjustment operation is performed by projecting the working distance detection index light obliquely to the center of the cornea of the subject's eye and obliquely detecting the index light reflected by the cornea from the front in parallel with the alignment operation. You. Thereafter, the automatic focus indicator light is projected on the fundus of the eye to be examined, and the reflected light is received by the television camera. Focusing is performed while moving a focus lens or the like along the optical path based on the reflected light. Then, at the same time that the focus is achieved, the stroboscopic discharge tube emits light and projects it on the fundus, and the fundus image is photographed by the photographing television camera.

In this fundus photographing apparatus, since the optical axis passes through the center of the pupil, a fundus portion near the point where the straight line passing through the center of the pupil and the rotation center of the eye to be examined intersects the fundus (hereinafter referred to as the front fundus portion) is photographed. Will be done.

By the way, in fundus photography, it may be necessary to photograph a fundus portion other than the front fundus portion (hereinafter referred to as a non-front fundus portion). In order to image the non-frontal fundus, first, a fixation lamp in an oblique direction as viewed from the eye to be examined is turned on, and the examiner stares at the fixation lamp, thereby rotating the eyeball by a predetermined angle. Next, alignment is performed so that the optical axis passes through the vertex of the eye to be examined (the portion closest to the fundus imaging optical system), and the vicinity of the point where the optical axis intersects the fundus (the non-frontal fundus portion) is photographed. You. In this case, the optical axis does not pass through the center of the pupil. Therefore, the optical axis passes near either the left or right iris of the optical axis in a cross-sectional view taken along a horizontal plane including the optical axis. For this reason, there is a problem that the iris portion blocks the illumination light from entering the fundus (so-called vignetting), so that a clear fundus image cannot be obtained as a whole.

[0006]

In order to obtain a clear image of the entire non-frontal fundus, a means for manually translating the optical axis so that the optical axis passes through the center of the pupil may be considered. However, this operation requires considerable skill and there is no guarantee that the movement will be accurate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a fundus photographing apparatus capable of easily and accurately photographing a non-frontal fundus portion and obtaining a clear fundus image as a whole. Its purpose is to provide.

[0008]

That is, the present invention provides an illumination optical system for illuminating the fundus of an eye to be examined with illumination light, a fundus imaging optical system for photographing the fundus based on the illumination light, and an alignment index light on the eye sphere. Index projection optical system for projecting an eye, an anterior ocular segment observation optical system for receiving the reflected alignment index light from the eye sphere, and a fundus image based on the position of the eye spherical reflection image observed by the anterior ocular segment observation optical system A first drive unit for guiding the fundus imaging optical system so that the optical axis of the optical system coincides with the vertex of the eye to be inspected; and a working distance adjustment unit for adjusting the working distance of the fundus imaging optical system. In a fundus imaging apparatus that fixes the line of sight of the subject's eye by illuminating the fixation lamp and shooting the fundus of the subject's eye, so that the optical axis of the fundus imaging optical system passes near the center of the pupil, Illuminated fixation Fundus imaging apparatus comprising an alignment correction means for guiding fundus photographing optical system in accordance with the position,
It is.

According to the present invention, there is provided an alignment correcting means for guiding the fundus photographing optical system so that the optical axis of the fundus photographing optical system passes near the center of the pupil in accordance with the position of the illuminated fixation lamp. Therefore, it is possible to easily and accurately photograph the non-frontal fundus, and to obtain a clear fundus image as a whole.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a fundus photographing apparatus according to the present invention, FIGS. 2 and 3 are flowcharts showing operation procedures of the fundus photographing apparatus shown in FIG. 1, and FIG. FIG. 5 is a horizontal cross-sectional view of the subject's eye showing a state in which the fundus is photographed using the fundus photographing apparatus shown in FIG. 1. FIG. 5 is a view for explaining the position of a fixation lamp of the fundus photographing apparatus shown in FIG. It is.

The fundus photographing apparatus shown in FIG. 1 has a direction of approaching / retreating with respect to the eye 1 to be examined (left-right direction in FIG.
It is called direction. ), A machine frame 3 that is movable in a horizontal direction (vertical direction in FIG. 1; hereinafter, referred to as X direction) and a vertical direction (vertical direction in FIG. 1, hereinafter referred to as Y direction). . Various devices to be described later are arranged on the machine frame 3.

To photograph the fundus using this fundus photographing apparatus, first, an alignment operation, a working distance adjustment operation, an alignment correction operation, and a focusing operation are performed. Next, the fundus is photographed by the fundus photographing optical system while the fundus is illuminated by the illumination optical system. First, the illumination optical system and the fundus imaging optical system will be described.

The illumination optical system comprises a strobe discharge tube 11, condenser lenses 12, 13, a circular slit 14, a mirror 15, a flat glass 17, a condenser lens 18, a condenser lens 20, and a perforated mirror 6. The visible light emitted from the strobe discharge tube 11 for photographing is focused by the condenser lenses 12 and 13 at the position of the circular slit 14,
14, is reflected by the mirror 15 and is reflected by the illumination optical axis 16.
The optical path can be bent upward. Further, this visible light travels on the illumination optical axis 16, passes through a flat glass 17, a condenser lens 18, a half mirror 19 of a focusing target projection optical system described later, and a condenser lens 20, and converges near the perforated mirror 6. , An image of the circular slit is formed on the perforated mirror 6. Further, this visible light is reflected by a perforated mirror 6, its optical path is bent on the photographing optical axis 4, passes through the objective lens 5 of the fundus photographing optical system, converges at the vertex position of the eye 1 to be examined, and the retinal surface of the fundus Is illuminated. The concave lens 26 and the mirror 25 are retracted from the photographing optical axis 4 at the time of this fundus illumination and during photographing described below.

The positions of the strobe discharge tube 11, the circular slit 14, and the vertex of the eye 1 are in a conjugate relationship.
That is, illumination light enters the eye 1 only through the ring-shaped passage of the circular slit 14 and illuminates the fundus through the pupil. At this time, the reflected light from the center of the cornea is cut and does not directly enter the objective lens.

The fundus photographing optical system comprises an objective lens 5, a focus lens 7, a relay lens 8, and a television camera (color television camera for photographing the fundus) 10. The objective lens 5 is for forming an optical pupil in the pupil of the eye 1 to be examined. The fundus image passes through the objective lens 5, the perforated mirror 6 of the illumination optical system, the focus lens 7, and the relay lens 8, is formed on the CCD light receiving surface 9 of the television camera 10, and is photographed. An image signal of the fundus from the television camera 10 is transmitted to the frame memory 4 via the image input / output control circuit 45.
6 and the fundus image is recorded (written).
The image is sent to the monitor display 47 and the fundus image is displayed. If necessary, the fundus image can be read from the frame memory 46 by the image input / output control circuit 45 and can be shot out from the video printer 48, so that an image print of the eye 1 to be examined can be attached to a medical chart.

The alignment operation performed prior to the fundus photographing is mainly performed by the alignment index projection optical system and the anterior ocular segment observation optical system.

The alignment index projection optical system includes an alignment light emitting diode 21, a mirror 22, and a condenser lens 2.
3, a mirror 25 and a concave lens 26. The concave lens 26 is for performing correction for canceling out the strong power of the objective lens, and a lens having a strong canceling power is used. The near-infrared light, which is the alignment index light emitted from the alignment light emitting diode 21, is reflected by the mirror 22.
And the optical path is bent on the alignment index optical axis 27a. This alignment index light passes through the condenser lens 23 and the half mirror 24 of the anterior ocular segment observation optical system, and is reflected by the mirror 25 (which is inserted on the imaging optical axis 4 during the alignment operation). The optical path can be bent upward. Further, the alignment index light passes through the concave lens 26 (inserted on the photographing optical axis 4 at the time of the alignment operation) and the objective lens 5 of the fundus photographing optical system, and is projected on the eye spherical surface 2 of the eye 1 to be examined.

The anterior eye observation optical system includes a half mirror 24,
It comprises an anterior segment observation lens 28 and an alignment television camera 30. Eye 2 of alignment index light
Is reflected by the mirror 25, and the optical path is bent on the alignment index optical axis 27a. Further, the reflected light is reflected by the half mirror 24, and the anterior ocular segment observation optical axis 27b
The optical path can be bent upward. And an anterior eye observation lens 2
8 is reflected by the alignment television camera 3
The light reaches the CCD light receiving surface 29 of 0 and forms an image. Note that the anterior eye image observed by the natural light or the illumination light such as the infrared LED is also input to the alignment television camera 30 along the same route as the reflected light.

A signal from the alignment television camera 30 is sent to the monitor display 4 via an image input / output control circuit 45.
7 is displayed on the screen of the monitor display 47.
A light spot and an anterior ocular segment image due to the reflected alignment index light from the camera are displayed, so that the alignment situation at the initial stage of the mechanical operation can be visually checked.

The XY direction position detection control circuit 49, which has received the electric signal from the image input / output control circuit 45, detects the position of the light spot on the image pickup screen due to the reflected light from the eye spherical surface 2. Then, a shift between the position of this light spot and the optical axis of the anterior ocular segment observation optical system (coincident with the imaging optical axis 4 of the fundus imaging optical system) is detected, and the gantry on which the machine frame 3 is mounted is moved to the first position. It is moved in the X and Y directions by an XY-axis driving mechanism 50 as a driving means, and guidance is made to eliminate this deviation. This completes the alignment operation.

Next, the working distance adjusting operation will be described. The working distance adjusting operation is performed by a working distance adjusting means including a working distance index projection optical system, a working distance detecting optical system, and a third drive mechanism.

The working distance index projection optical system includes a light emitting diode (infrared LED) 31 for adjusting the working distance and a condenser lens 3.
2. Working distance detection index slit 33 and projection lens 3.
4 Light emitting diode 31 for adjusting working distance
Is traveling on the working distance detection index optical axis 35a, the condenser lens 32, the working distance detection index slit 3
3. The light passes through the projection lens 34 sequentially and is incident on the ocular sphere 2. The light is incident at an angle of 45 degrees with respect to the photographing optical axis 4.

The working distance detecting optical system includes a condenser lens 36 and a working distance detecting light receiving element (PSD) 37. As described above, the index light is incident on the eye sphere 2 and is reflected there. In the stage after the working distance is adjusted, the reflection is made in the direction of 45 degrees with respect to the photographing optical axis 4, and the reflected light travels on the working distance detecting optical axis 35b, passes through the condenser lens 36, and passes through the working lens 36. The light is incident on the light receiving element 37 for detection.

Before the working distance is adjusted, the machine frame 3 is arranged so that the fundus photographing optical system and the eyeball are located at a distance greater than a predetermined distance. At this stage, the index light from the working distance adjusting light emitting diode 31 is
Is not incident on the vertex (the vertex of the eye to be inspected), so that the reflected light is not reflected in the 45-degree direction. Therefore, the reflected light is not caught by the light receiving element 37 for detecting the working distance. When the machine frame 3 is moved in the direction approaching the eye sphere 2 by the Z-axis drive mechanism 52 as the third drive means, and the index light is incident on the vertex of the eye to be examined, the reflected light is reflected in the 45 ° direction, and the working distance The detection light receiving element 37 catches the reflected light. At this time, the Z-axis drive mechanism 52 is stopped by the working distance detection control circuit 51, and the working distance adjustment operation is completed.

The alignment light emitting diode 21
Is turned on, and the working distance adjusting operation performed by turning on the working distance adjusting light emitting diode 31 proceeds simultaneously. At this time, in order to prevent the index light of the alignment light emitting diode 21 and the index light of the working distance adjusting light emitting diode 31 from interfering with each other, they are repeatedly blinked so as to be alternately turned on.

Next, the fixation lamp will be described with reference to FIGS. The first fixation lamp group S1 including the right-eye fixation lamp group SR and the left-eye fixation lamp group SL is located at the same position in the Y direction and the Z direction as the alignment light emitting diode 21 and is shifted in the X direction. Are arranged. That is, a plurality of fixation lamps S (three on each side in the embodiment of FIG. 5) are arranged side by side in the X direction. A predetermined fixation light S is turned on from among the fixation lights SR for the right eye when photographing the right eye and from the fixation lights SL for the left eye when photographing the left eye. By causing the examiner to fixate the fixation lamp S, the subject's eye rotates by a predetermined angle, and a desired non-frontal fundus portion is photographed.

By selecting and turning on a desired fixation lamp S from the fixation lamp group S1 in this manner, for example, in the case of a periodic examination in which the non-frontal fundus portion to be photographed is predetermined, the fixation is performed. The operation for selecting the lamp S and the alignment correction operation described later can be easily performed. Needless to say, instead of the type of selecting the desired fixation light S from the fixation light group S1 as described above, for example, a fundus imaging apparatus of a type that can change the fixation light position steplessly by, for example, a sliding operation, The present invention can be applied.

The first fixation lamp group S1 shown in FIG.
Is provided on the alignment index projecting optical system and is turned on during the alignment operation. A second fixation lamp group (not shown) having the same configuration as the first fixation lamp group
Is provided on a focusing index projection optical system described later, and this second fixation lamp group is turned on at the time of focusing and at the time of photographing the fundus.
Both fixation lamps are aligned so that they can be seen at the same position from the subject's eye. Even if the optical axis is switched from the alignment index projection optical system to the fundus imaging optical system, the fixation lamp viewed from the subject's eye The position does not change.

Next, the alignment correction operation, which is the greatest feature of the present invention, will be described with reference to FIGS. The alignment correction operation is performed after the alignment operation and the working distance adjustment operation are completed.

In FIG. 4, a point S indicates the position of the fixation lamp. This fixation lamp S is, as described above, a fixation lamp group S for the right eye.
A predetermined one is selected from R and the fixation group SL for the left eye. By causing the subject to stare at the fixation lamp S, the line of sight of the subject's eye 1 is directed obliquely. A two-dot chain line from the pupil center PC to the point S substantially coincides with the line of sight of the subject's eye 1. Symbols Ia and Ib are iris parts. Although the iris has an annular shape, for convenience, the left iris portion is the iris portion Ia and the right iris portion is the iris portion Ib when viewed from the subject.
Called.

When the alignment operation is completed, the photographing optical axis 4 of the fundus photographing optical system passes through the vertex ER of the eye to be examined. That is, the imaging optical axis 4 coincides with the two-dot chain line m passing through the vertex ER of the eye to be inspected in FIG. If you do fundus photography as it is,
Since the photographing optical axis 4 is close to the iris portion Ia, incidence of illumination light to the fundus is blocked by the iris portion Ia, and a clear fundus image cannot be obtained as a whole.

In the alignment correction operation, the fundus photographing optical system is moved by a distance L so that the photographing optical axis 4 passes through the pupil center PC. That is, the photographing optical axis 4 after the alignment correction operation is made to coincide with the two-dot chain line n passing through the pupil center PC in FIG. As a result, the photographing optical axis 4 is located at the same distance from both the iris portions Ia and Ib, so that the entrance of illumination light is not blocked, and a clear fundus image can be obtained as a whole. In this alignment correction operation, the photographing optical axis 4 does not necessarily have to completely coincide with the pupil center PC, and may deviate from the pupil center PC and pass therearound in a range where a clear fundus image can be obtained as a whole. . The non-frontal fundus near the point A where the photographing optical axis 4 intersects the fundus G after the alignment correction operation is the fundus to be photographed.

Such an alignment correction operation is performed by an alignment correction unit including an X-direction correction value detection circuit 58 (see FIG. 1) and an XY-axis driving mechanism 50 as a second driving unit. The X direction correction value detection circuit 58
An appropriate moving distance L of the photographing optical axis 4 corresponding to the position of the fixation lamp S is read from a look-up table prepared in advance and recorded in the memory. Then, the signal of the moving distance L is sent to the XY-axis driving mechanism 50. The XY-axis driving mechanism 50 moves the machine frame 3 in the X direction by a moving distance L based on the transmitted signal. This completes the alignment correction operation. Since the movement of the photographing optical axis 4 is automatically performed in this manner, the alignment correction operation is simply and accurately performed.

In the present embodiment, the first driving means during the alignment operation is used as the second driving means during the alignment correction operation.
Driving means is used. That is, the XY-axis drive mechanism 50 plays both roles of the first drive mechanism and the second drive mechanism. Of course, both drive mechanisms may be configured by separate members.

In this embodiment, the alignment correction operation is performed in the X direction. However, the direction of the correction operation may be performed in the Y direction or in both the X and Y directions according to the location to be photographed. .

Next, the focusing operation will be described. After the alignment operation, the working distance adjustment operation, and the alignment correction operation are completed, the focusing operation is performed by a focusing unit including a focusing target projection optical system and a focusing control mechanism.

The focusing index projection optical system includes a halogen lamp 3
8, condensing lens 39, slit 40 for automatic focus index, projection lens 41, split prism 42, condensing lens 4
4 and a half mirror 19. Among them, a halogen lamp 38, a condenser lens 39, a slit 40 for an automatic focus index, a projection lens 41, and a split prism 42
Form the movable part 60 integrally.

The light from the halogen lamp 38 is condensed by a condenser lens 39, a slit 40 for an automatic focus index, and a projection lens 41.
And the split mirror 42 and the half mirror 1
The light path is reflected on the illumination optical axis 16. Further, this light beam is reflected by the perforated mirror 6 through the condenser lens 20, the optical path is bent on the photographing optical axis 4, and the corneal reflection light is eliminated and incident on the eye 1 to be examined through the objective lens 5. And reach the fundus. At the time of focusing, the concave lens 26 and the mirror 25 are retracted from the photographing optical axis 4.

The fundus image formed by the light from the halogen lamp 38 travels along the photographing optical axis 4 from the subject's eye 1 and forms a fundus image on the CCD light receiving surface 9 of the television camera 10. The movable unit 60 of the focusing index projection optical system and the focus lens 7 of the fundus photographing optical system are linked together so that the fundus image is in a focused state.
The lens moves in the axial direction, and focusing is performed. In the present embodiment, the focus detection of the fundus and the imaging of the fundus are performed by the same television camera 10. However, the optical path of the fundus photographing optical system is branched behind the focus lens 7 and arranged on the branched optical axis. The focus may be detected by the focused focus detection CCD or PSD.

Next, the operation procedure of the fundus photographing apparatus will be described with reference to the flowcharts of FIGS. Note that FIG.
The end point M in the flowchart of FIG. 3 matches the start point M in the flowchart of FIG.

First, when the photographing button of the fundus camera which is turned on and is in a standby state is pressed, an external image by the anterior ocular segment observation optical system is displayed on the monitor display 47. The subject fixes his / her head on the jaw table and looks at the fixation lamp S through the objective lens 5 according to the doctor's instructions. At this time, the objective lens 5
Detects whether the subject's eye is the right eye or the left eye. A predetermined fixation light selected from the fixation light group for the left eye SR and the fixation light group for the right eye SL is turned on based on a signal from the jaw table.

Next, the doctor operates the jaw table, adjusts the monitor display 47 so that the anterior segment of the subject's eye 1 is displayed on the monitor display 47, and presses the photographing button again. By this second button pressing operation, the alignment light emitting diodes 21 as the alignment index and the working distance adjusting light emitting diodes 31 as the working distance detection index are alternately turned on.
Next, the doctor sets the Z axis until the image (light spot) of the alignment index light by the reflected light from the eyeball 2 of the alignment index light can be recognized in the anterior eye image captured on the imaging screen of the alignment television camera 30. By driving, the machine frame 3 is advanced in the Z direction.

When an image (light spot) of the alignment index light is recognized on the imaging screen of the television camera 30 for alignment, the position of this light spot is automatically adjusted until it enters a predetermined range of XY alignment at the center of the imaging screen. Then, the X axis and the Y axis are driven, and the machine frame 3 moves. This state is displayed on the screen of the monitor display 47.

When the light spot of the alignment index light comes within a predetermined range at the center of the image pickup screen in this way, the alignment is performed while following the light spot within the predetermined range, and the machine frame 3 driven by the Z axis is driven. Is started. Z of this machine frame 3
When the working distance detection index image (eyeball reflected light) is detected by the working distance detection control circuit 51 during forward movement in the direction, the driving operation of the X axis, Y axis, and Z axis is stopped.

Next, the X-direction correction value detection circuit 58 reads an appropriate moving distance L of the photographing optical axis 4 corresponding to the position of the fixation lamp S from the lookup table. Then, the signal of the moving distance L is sent to the XY-axis driving mechanism 50. The XY-axis driving mechanism 50 moves the machine frame 3 in the X direction by the moving distance L based on the transmitted signal (alignment correction operation).

When the alignment correcting operation is completed, the alignment light emitting diode 21 and the working distance adjusting light emitting diode 31 are turned off. Next, the optical path switching mechanism 54 receiving the signal from the optical path switching control mechanism 53 retreats the concave lens 26 and the mirror 25 from above the photographing optical axis 4, and moves the concave lens 26 and the mirror 25 to the optical path between the anterior ocular segment observation optical system and the fundus imaging optical system. Can be switched. Further, a halogen lamp 38 which is an automatic focus index light source (AF index) of the focus index projection optical system is turned on,
The focus lens 7 and the movable unit 60 move and scan on their optical axes in conjunction with each other, and the focus of the fundus image is detected.

When the in-focus state is detected, the halogen lamp 38 is turned off, the stroboscopic discharge tube 11 emits light, and the fundus image is photographed by the fundus imaging color television camera 10. After the photographed fundus image is recorded in the frame memory 46 and displayed on the monitor display 48, the machine frame system 3 returns to the initial standby position and enters the standby state.

When operating the fundus photographing apparatus,
The image from the television camera 10 of the anterior ocular segment observation optical system may be displayed on the monitor by pressing the photographing button even after the subject's head is fixed to the jaw base.

In the present invention, the fundus photographing apparatus is provided with the alignment correcting means. However, such an alignment correcting means is not limited to the fundus photographing apparatus. The present invention can be applied to all devices for observing and photographing a deep part.

[0051]

As described above, in the fundus imaging apparatus according to the present invention, the alignment in the X and Y directions is performed so that the imaging optical axis of the fundus imaging optical system passes through the vertex of the eye to be inspected. Automatically performs an alignment correction operation in the X direction so that the image passes near the center of the pupil, so that a non-frontal fundus can be easily and accurately photographed, and a clear fundus image can be obtained as a whole. .

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an embodiment of a fundus imaging apparatus according to the present invention.

FIG. 2 is a flowchart illustrating an operation procedure of the fundus imaging apparatus illustrated in FIG. 1;

FIG. 3 is a flowchart illustrating an operation procedure of the fundus imaging apparatus illustrated in FIG. 1;

FIG. 4 is a horizontal cross-sectional view of an eye to be inspected, showing a state of photographing a fundus using the fundus photographing apparatus shown in FIG. 1;

FIG. 5 is a diagram illustrating the position of a fixation lamp of the fundus imaging apparatus illustrated in FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Eye to be examined 2 ... Eye spherical surface 3 ... Machine frame 4 ... Photographing optical axis 5 ... Objective lens 6 ... Perforated mirror 7 ... Focus lens 8 ... Relay Lens 9, 29: CCD light receiving surface 10, 30, Television camera 11: Strobe discharge tube 12, 13, 18, 20, 23, 32, 36, 39, 4
DESCRIPTION OF SYMBOLS 4 ... Condensing lens 14 ... Circular slit 15, 22, 25 ... Mirror 16 ... Illumination optical axis 17 ... Flat glass 21 ... Alignment light emitting diode 24 ... Half mirror 26 ... Concave lens 27a ... Alignment index optical axis 27b ... Anterior eye observation optical axis 28 ... Anterior eye observation lens 31 ... Working distance adjusting light emitting diode 33 ... Working distance detection index Slits 34 and 41 Projection lens 35a Working distance detection index optical axis 35b Working distance detection optical axis 37 Light receiving element for working distance detection 38 Halogen lamp 40 Automatic Focus index slit 42: Split prism 45: Image input / output control circuit 46: Frame memory 47: Monitor display 48: Video printer 49 · XY direction position detection control circuit 50 ··· XY axis drive mechanism 51 ··· working distance detection control circuit 52 ··· Z axis drive mechanism 53 ··· optical path switching control circuit 54 ··· optical path switching mechanism 58. · Y direction correction value detection circuit 60 ··· movable part S · · · fixation lights SR · · · right eye fixation lights SL · · · left eye fixation lights S1 · · · fixation lights Ia, Ib: Iris part PC: Center of pupil ER: Apex of eye to be examined

Claims (2)

[Claims] 1. An illumination optical system for illuminating the fundus of an eye to be examined with illumination light, a fundus imaging optical system for photographing the fundus based on the illumination light, and an alignment index projection optical system for projecting alignment index light onto the eye spherical surface. The optical axis of the fundus imaging optical system is based on the anterior eye observation optical system that receives the reflected light of the alignment index light from the eye sphere, and the fundus imaging optical system based on the position of the eye spherical reflection image observed by the anterior eye observation optical system. First driving means for guiding the fundus photographing optical system so as to coincide with the working distance, and working distance adjusting means for adjusting the working distance of the fundus photographing optical system. In a fundus imaging apparatus that fixes the line of sight of the subject's eye by staring, the fundus imaging apparatus captures the fundus of the subject's eye, according to the position of the fixed fixation lamp so that the optical axis of the fundus imaging optical system passes near the center of the pupil. Optics Fundus photographing apparatus comprising the alignment correcting means for guiding. 2. A fixation lamp group comprising a plurality of fixation lamps, wherein one fixation lamp is selected from the fixation lamp group and turned on, thereby rotating the subject's eye by a desired angle. The fundus imaging apparatus according to claim 1, wherein the fundus imaging apparatus captures a desired portion of the fundus.