JP2008006105A - Fundus camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible capture a favorable fundus image by facilitating the alignment even for an examiner being unused to the operation. <P>SOLUTION: This fundus camera having a capturing section disposed with a fundus capturing optical system for capturing the image of the fundus of a subject's eye is provided with an alignment light projection means projecting an alignment light flux to the cornea of the subject's eye, a first detection means detecting a corneal reflex light by the alignment light flux and detecting the cornea apex position, an image pickup means for capturing the image of the anterior ocular segment of the subject's eye, a second detection means detecting the pupil center position by a signal from the image pickup means, and a guide means guiding the image pickup section based on the cornea apex position detected by the first detection means and the pupil center position detected by the second detection means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fundus camera that photographs the fundus of a subject's eye.

A fundus camera that photographs the fundus of the subject's eye is generally one that performs fundus photography by aligning the photographing optical axis with the corneal apex of the subject's eye (see Patent Document 1). Patent Document 2 also proposes a fundus camera that performs fundus photographing by aligning the photographing optical axis at the center of the pupil of the subject's eye.
Japanese Patent Laid-Open No. 8-27592 Japanese Patent Laid-Open No. 10-295644

  By the way, at the time of photographing around the fundus, the eccentricity between the corneal apex and the pupil center increases. For this reason, when aligning to the corneal apex, the fundus illumination light is likely to be blocked by the iris of the subject's eye, and a portion of the fundus image may become dark due to insufficient illumination light quantity. Further, when aligning with the center of the pupil, flare due to the reflection of the cornea or the crystalline lens is likely to occur in the fundus image as compared with the method of aligning with the apex of the cornea.

  In view of the above problems, it is an object of the present invention to provide a fundus camera that can easily perform alignment adjustment even for an examiner unfamiliar with operation and can capture a good fundus image.

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

(1) In a fundus camera having a photographing unit for arranging a fundus photographing optical system for photographing the fundus of a subject's eye,
Alignment light projection means for projecting an alignment beam onto the cornea of the subject's eye;
First detection means for detecting a corneal apex position by detecting corneal reflected light by the alignment light beam;
Imaging means for imaging the anterior segment of the subject's eye;
Second detection means for detecting a pupil center position based on a signal from the imaging means;
Guidance means for guiding the imaging unit based on a corneal apex position detected by the first detection means and a pupil center position detected by the second detection means;
It is characterized by providing.
(2) The fundus camera of (1)
A display means capable of switching and displaying a fundus image and an anterior ocular segment image;
The guiding means electronically displays an alignment mark indicating the corneal apex and an alignment mark indicating the pupil center on the screen on which the anterior segment image is displayed by the display means based on the detection results of the first detection means and the second detection means. Display simultaneously.
(3) In the fundus camera of (2),
A fixation target presenting means capable of changing the position of the fixation target for guiding the eye of the subject's eye;
The guide means electronically displays a reticle serving as a reference for performing alignment using the alignment mark, and the display shape of the reticle according to the fixation target presentation position changed by the fixation target presentation means It is characterized by changing.
(4) In the fundus camera of (1),
A position of a predetermined alignment reference point formed between the corneal apex position and the pupil center position based on the corneal apex position detected by the first detection means and the pupil center position detected by the second detection means. A reference point position detecting means for detecting,
The guiding means includes
An alignment mark indicating the alignment reference point is electronically displayed on a screen on which an anterior segment image is displayed by the display unit based on a detection result of the reference point position detection unit.
(5) In the fundus camera of (1),
Driving means for driving the imaging unit;
A position of a predetermined alignment reference point formed between the corneal apex position and the pupil center position based on the corneal apex position detected by the first detection means and the pupil center position detected by the second detection means. A reference point position detecting means for detecting,
The guiding means includes
Control means for controlling the drive means so that an alignment deviation amount between the position of the alignment reference point detected by the reference point position detection means and the imaging optical axis of the fundus imaging optical system satisfies a predetermined allowable range; It is characterized by providing.

  According to the present invention, even an examiner who is unfamiliar with the operation can easily perform alignment adjustment, and a good fundus image can be taken.

  Embodiments according to the present invention will be described below with reference to the drawings. FIG. 1 is an external configuration diagram of a fundus camera according to the present embodiment.

  The fundus camera includes a base 1, a movable base 2 that can move in the left and right direction (X direction) and the front and rear (working distance) direction (Z direction) with respect to the base 1, and a three-dimensional direction with respect to the movable base 2. And a face support unit 5 fixed to the base 1 in order to support the face of the subject. The imaging unit 3 is moved in the left-right direction, the up-down direction (Y direction), and the front-rear direction with respect to the subject eye E by an XYZ drive unit 6 provided on the moving table 2. The movable table 2 is moved in the XZ direction on the base 1 by operating the joystick 4. Further, by rotating the rotary knob 4a, the XYZ driving unit 6 is driven in the Y direction and the photographing unit 3 is moved in the Y direction. A monitor 8 that displays a fundus observation image or a fundus image is provided on the examiner side of the imaging unit 3.

  FIG. 2 is a schematic configuration diagram of an optical system and a control system housed in the photographing unit 3. The optical system is roughly divided into an illumination optical system 10, a fundus observation / photographing optical system 30, an alignment index projection optical system 50, an anterior ocular segment observation optical system 60, and a fixation target presenting optical system 70.

  <Illumination Optical System> The illumination optical system 10 includes an observation illumination optical system and a photographing illumination optical system. The photographing illumination optical system includes a photographing light source 14 such as a flash lamp, 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, and a hole. A perforated mirror 22 and an objective lens 25 are provided. The observation illumination optical system includes a light source 11 such as a halogen lamp, an infrared filter 12 that transmits near-infrared light having a wavelength of 750 nm or more, 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 objective lens 25 is provided. The dichroic mirror 16 has a characteristic of reflecting infrared light and transmitting visible light.

  <Fundus Observation / Shooting Optical System> The fundus oculi observation / shooting optical system 30 includes an objective lens 25, a photographing aperture 31 located near the aperture of the perforated mirror 22, a focusing lens 32 movable in the optical axis direction, and an imaging lens 33. When the fundus is photographed, a flip-up mirror 34 that can be inserted / removed from the optical path by the insertion / removal mechanism 39 is provided. . The photographing aperture 31 is disposed at a position substantially conjugate with the pupil of the subject eye E with respect to the objective lens 25. The focusing lens 32 is moved in the optical axis direction by a moving mechanism 49 including a motor. Reference numeral 35 denotes a photographing two-dimensional image sensor having sensitivity in the visible range. In the optical path in the reflection direction of the flip-up mirror 34, a dichroic mirror 37 having infrared light reflection and visible light transmission characteristics, a relay lens 36, and an observation two-dimensional imaging device 38 having sensitivity in the infrared region are arranged. .

  A dichroic mirror (wavelength selective mirror) 24 that can be inserted and removed as an optical path branching member is provided obliquely between the objective lens 25 and the perforated mirror 22. The dichroic mirror 24 reflects the wavelength light (center wavelength 940 nm) of the alignment index projection optical system 50 and the anterior segment illumination light source 58, and the wavelength light of the fundus observation illumination and the light source wavelength (center wavelength of the focus index projection optical system 40). 880 nm) and a wavelength of 900 nm or less. At the time of shooting, the dichroic mirror 24 is flipped up by the insertion / removal mechanism 66 and retracts out of the optical path. The insertion / removal mechanism 66 can be composed of a solenoid and a cam.

  The light beam emitted from the observation light source 11 is converted into an infrared light beam by the infrared filter 12 and reflected by the condenser lens 13 and the dichroic mirror 16 to illuminate the ring slit 17. The light transmitted through the ring slit 17 reaches the perforated mirror 22 through the relay lens 18, the mirror 19, the black spot plate 20, and the relay lens 21. The light reflected by the perforated mirror 22 is transmitted through the dichroic mirror 24, once converged near the pupil of the subject eye E by the objective lens 25, and then diffused to illuminate the subject eye fundus.

  Reflected light from the fundus is obtained by the objective lens 25, the dichroic mirror 24, the aperture of the perforated mirror 22, the photographing aperture 31, the focusing lens 32, the imaging lens 33, the flip-up mirror 34, the dichroic mirror 37, and the relay lens 36. Then, an image is formed on the image sensor 38.

  Further, the fundus is illuminated with visible light by the light emission of the photographing light source 14, and the reflected light from the fundus is reflected by the objective lens 25, the aperture of the perforated mirror 22, the photographing aperture 31, the focusing lens 32, the imaging lens 33, and the jumping up. An image is formed on the two-dimensional image sensor 35 through the mirror 34.

  <Alignment Index Projection Optical System> An alignment index projection optical system 50 that projects an alignment beam onto the cornea of a subject's eye collimates with an infrared light source 51 that is symmetrically disposed in the left-right direction about the photographing optical axis L1. A first index projection optical system having a lens 52, and a second index disposed symmetrically across a vertical plane having an optical axis disposed at a narrower angle than the first index projection optical system and passing through the optical axis L1. A second index projection optical system having two infrared light sources 53. The first index projection optical system projects an infinite index on the cornea of the subject eye E, and the second index projection optical system projects a finite index on the cornea of the subject eye E. Note that the second index projection optical system is provided below the first index projection optical system so that the projected index beam does not reach the pupil of the subject's eye.

  <Anterior Eye Observation Optical System> The anterior eye observation optical system 60 includes a field lens 61, a mirror 62, a diaphragm 63, a relay lens 64, and a two-dimensional imaging element 65 having sensitivity in the infrared region on the reflection side of the dichroic mirror 24. Is provided. The two-dimensional imaging element 65 also serves as an imaging means for detecting an alignment index, and the anterior segment illuminated by the anterior segment illumination light source 58 that emits infrared light having a center wavelength of 940 nm and the alignment index are imaged. The anterior segment illuminated by the anterior segment illumination light source 58 is received by the two-dimensional imaging element 65 from the objective lens 25, the dichroic mirror 24, and the field lens 61 via the relay lens 64 optical system. Further, when the light source of the alignment index projection optical system 50 is turned on, the corneal reflected light by the alignment light beam is detected by the two-dimensional image sensor 65. The output of the two-dimensional image sensor 65 is input to the control unit 80, and the anterior eye image F captured by the two-dimensional image sensor 65 is displayed on the monitor 8 as shown in FIG. The anterior ocular segment observation optical system 60 also serves to detect the alignment state of the apparatus main body with respect to the subject eye.

  Further, around the hole of the perforated mirror 22, two infrared light sources 55 (center wavelength 880 nm) for forming an optical alignment index (working dot W1) on the cornea of the subject's eye are left and right about the optical axis L1. Arranged symmetrically. The light source 55 may be configured such that the end face of the optical fiber is disposed in the vicinity of the perforated mirror 22 and the infrared light is guided to the optical fiber. Here, the corneal reflected light from the light source 55 is reflected on the imaging surface of the imaging element 38 arranged at a substantially conjugate position with the fundus when the working distance between the subject eye E and the imaging unit 3 (apparatus body) becomes appropriate. An image is formed. The above configuration is used as an index projection optical system for finely adjusting the alignment while observing the fundus of the subject's eye. In this case, the fundus oculi observation optical system 30 also serves to guide the corneal reflection image from the light source 55 to the image sensor 38.

  <Fixation Target Presenting Optical System> A fixation target presenting optical system 70 for guiding the line of sight of a subject's eye includes a red light source 74, a light shielding plate 71 having eight light shielding plates 71 in which aperture holes are formed, and a relay. A lens 75 is provided, and the optical path of the observation optical system 30 from the flip-up mirror 34 to the objective lens 25 is shared through the dichroic mirror 37. The eight light shielding plates 71 are each provided with opening holes 71a to 71h. When the disk plate 72 is rotationally driven by a pulse motor 73 and each light shielding plate 71 is selectively disposed in front of the light source 74, the fixation target corresponds to the opening holes 71a to 71h as shown in FIG. Are presented at eight positions 91L, 91R, 92 to 97 with respect to the optical axis L2. Refer to Japanese Patent Application Laid-Open No. 2004-290535 for the detailed configuration of the above configuration.

  The light flux from the fixation target passes through the relay lens 75, the dichroic mirror 37, the flip-up mirror 34, the imaging lens 33, the focusing lens 32, the perforated mirror 22, the dichroic mirror 24, and the objective lens 25. The light is collected and the subject visually recognizes the light flux from any one of the predetermined opening holes 71a to 71h as a fixation target.

  The fixation target presentation optical system 70 is configured to be able to change the fixation target presentation position between a standard position for photographing the fundus central part and a peripheral position for photographing the fundus peripheral part. That is, the fixation target position 91R corresponding to the opening hole 71b is used when photographing the vicinity of the posterior pole of the fundus including the right eye's macular and optic nerve head in a balanced manner. 91R is the standard position for right-eye photography. On the other hand, the fixation target position 91L corresponding to the opening hole 71a is used when photographing mainly in the vicinity of the posterior pole of the fundus including the left eye's macular and optic nerve head in a balanced manner. Is the standard position for left-eye photography. The fixation target positions 92 to 97 corresponding to the opening holes 71c to 71h are set as positions for peripheral photographing.

  <Control System> Outputs of the two-dimensional imaging elements 65, 38, and 35 are connected to the control unit 80. The control unit 80 detects the alignment index from the anterior segment image captured by the two-dimensional image sensor 65 and detects the focus index from the fundus image captured by the two-dimensional image sensor 38. The control unit 80 is connected to the monitor 8 and controls the display image. In addition, the control unit 80 includes an XYZ driving unit 6, a moving mechanism 49, an insertion / removal mechanism 39, an insertion / removal mechanism 66, a pulse motor 73, a rotary knob 4a, a photographing switch 4b, a switch unit 84 having various switches, and a memory. A memory 85 as a means, each light source, and the like are connected. The switch unit 84 is provided with a focus adjustment switch 84a for adjusting the focus of the fundus image, a fixation target presentation switch 84b for changing the position of the fixation target for the subject's eye, and the like.

  The operation of the fundus camera having the above configuration will be described separately for the case of photographing the center position of the fundus (standard photographing) and the case of photographing the peripheral position of the fundus (peripheral photographing). The following description is for the case where the right eye is photographed.

  Here, the examiner sets the fixation target presentation position by the switch 84b. FIG. 4 is an example of an anterior ocular segment observation screen displayed on the display screen of the monitor 8 when photographing the fundus center. FIG. 5 is an example of an anterior segment image observation screen displayed on the monitor 8 when photographing the fundus periphery, and is a diagram in the case of photographing a region around the nipple in the right eye. First, the face of the subject is supported by the face support unit 5. At the initial stage, the dichroic mirror 24 is inserted in the optical path of the photographing optical system 30, and the anterior segment image captured by the two-dimensional image sensor 65 is displayed on the monitor 8. The examiner moves the imaging unit 3 left and right and up and down by operating the joystick 4 so that the anterior segment image appears on the monitor 8. When the anterior segment image appears on the monitor 8, four index images Ma, Mb, Mc, and Md also appear as shown in FIG. 4 (a) or FIG. 5 (a).

  At the center of the screen of the monitor 8, a reticle LT serving as a reference for alignment is electronically formed by the control unit 80, and the cross mark M at the center of the reticle LT represents the position of the photographing optical axis L1 (alignment). Center), and a circular mark (reticle LT) represents an allowable range of alignment. Note that the diameter of the reticle LT may represent a pupil diameter (required pupil diameter) necessary for causing the illumination light beam to enter the fundus.

  The control unit 80 obtains the coordinate positions of the four index images Ma to Md from the image pickup signal from the image sensor 65, and uses the coordinates of the intermediate point between the index image Ma and the index image Mb formed by an infinite light beam as the corneal vertex position. Detect as coordinates. In addition, the control unit 80 extracts the pupil part of the subject's eye from the imaging signal from the imaging element 65, and detects the pupil center from the extracted pupil part. Then, the coordinates of the pupil center position are detected. In this case, since the pupil portion of the subject's eye is imaged darker than the other portions, for example, extraction can be performed by comparing the amount of light with the surrounding (iris). The pupil center can be detected, for example, by obtaining the center of gravity of the extracted pupil portion.

  When the position of the corneal apex is detected, the control unit 80 electronically displays an alignment index (mark) C1 at the position of the monitor 8 corresponding to the position. When the apparatus main body moves relative to the subject's eye in the XY directions, the coordinate positions of the index images Ma and Mb move accordingly. Therefore, the alignment index C1 is always the intermediate point between the index images Ma and Mb, that is, the monitor. 8 is moved and displayed so as to be positioned approximately at the apex of the cornea in the anterior segment image on the upper side.

  Further, when the position of the pupil center is detected, the control unit 80 electronically displays an alignment index (mark) P1 at the position of the monitor 8 corresponding to the position. When the apparatus main body moves relative to the subject's eye in the X and Y directions, the pupil center position moves accordingly, so that the alignment index P1 is always located substantially at the center of the pupil in the anterior segment image on the monitor 8. Moved and displayed.

  Further, the control unit 80 changes the display shape of the reticle LT that is electronically displayed according to the fixation target presentation position. In this case, when the subject's eye is fixed to the periphery, the amount of eccentricity between the corneal apex of the subject's eye and the pupil center increases in accordance with the amount of shake in the line of sight. Therefore, the reticle according to the line-of-sight direction in which the eye to be examined is guided so that the alignment index C1 and the alignment index P1 are positioned within the frame of the reticle LT when the alignment deviation amount satisfies a predetermined alignment allowable range. The display shape of LT is increased. More specifically, when the line of sight of the subject's eye is shaken in the left-right direction, the circular mark of the reticle LT has an elliptical shape having a major axis in the left-right direction (see FIG. 5) and is longer than the other directions. In addition, when the line of sight of the subject's eye is shaken in the vertical direction, the circular mark of the reticle LT has an elliptical shape having a major axis in the vertical direction (see FIG. 5) and is longer than the other directions.

  When the alignment is performed in the state in which the anterior eye image, the alignment indices C1, P1, the reticle LT, and the like are displayed on the monitor 8 as described above, the examiner, as shown in FIG. 4B or FIG. The imaging unit 3 is placed on the subject's eye so that the space between the alignment index C1 indicating the corneal apex position and the alignment index P1 indicating the pupil center position (preferably near the intermediate position) is positioned at the cross mark of the reticle LT. XY alignment is performed by moving. In this case, the alignment may be performed so that the alignment index C1 and the alignment index P1 are positioned within the mark of the reticle LT.

  The alignment deviation amount in the Z direction is calculated by comparing the interval between the index images Ma and Mb and the interval between the index images Mc and Md. Here, when the photographing unit 3 is displaced in the working distance direction, the control unit 80 changes the image interval between the index images Mc and Md while the interval between the infinity indexes Ma and Mb hardly changes. The amount of alignment deviation in the working distance direction with respect to the subject's eye is obtained using the characteristic of performing (for details, refer to JP-A-6-46999).

  Then, the control unit 80 displays an indicator or the like representing the misalignment in the Z direction based on the Z-direction alignment deviation detected as described above (not shown). Here, the examiner performs alignment in the Z direction so as to display that the proper working distance has been reached.

Here, when the alignment in the X, Y, and Z directions in the observation state of the anterior segment image is completed, the examiner presses the display changeover switch provided in the switch unit 84 to change the observation image displayed on the monitor 8 from the anterior segment image. Switch to the fundus image.
FIG. 6 is an example of a fundus image displayed on the monitor 8 when photographing the fundus periphery, and is a diagram in the case of photographing an area centered on the nipple in the right eye.

  When the alignment state is appropriately adjusted, two working dots W of corneal reflection formed by the light source 55 appear in the fundus image. While examining the fundus image, the examiner confirms the focus of the working dot W, the flare of the fundus image, and the like, and further finely adjusts the alignment state by manual operation of the joystick 4 so that photographing can be performed in a desired state. Further, since focus index images S1 and S2 are projected at the center by a focus index projection optical system (not shown), the focus adjustment switch 84a is operated on the basis of the index image to focus the fundus. Then, after the fine alignment adjustment and the focus adjustment are completed, the examiner presses the photographing switch 83 to perform photographing.

  With the configuration as described above, the photographing optical axis L1 is easily aligned near the middle position between the corneal apex of the subject's eye and the center of the pupil. Therefore, it is possible to perform alignment at a position suitable for photographing by a simple alignment operation, and a good fundus image can be photographed even if it is not an expert. In the above description, the imaging unit 3 is guided so that the imaging optical axis L1 is aligned near the middle position between the corneal vertex of the subject's eye and the center of the pupil. The imaging unit 3 may be guided so that the imaging optical axis L1 is aligned between the center of the pupil and the center of the pupil.

  In the display control as described above, the position of a predetermined alignment reference point formed between the corneal apex position and the pupil center position is detected based on the position of the corneal apex and the pupil center detected as described above. Then, the alignment index K1 may be electronically displayed at the position of the monitor 8 corresponding to the position. More specifically, as shown in FIG. 7, the coordinates of the intermediate position K between the corneal apex position C and the pupil center position P are detected, and the alignment index K1 is electronically placed at the position of the monitor 8 corresponding to that position. You may make it display (refer FIG. 8). When the apparatus main body moves relative to the subject's eye in the XY directions, the intermediate position K between the corneal apex position and the pupil center position moves accordingly, so that the alignment index K1 is always the anterior segment image on the monitor 8. And moved so as to be positioned at an intermediate position between the corneal apex position and the pupil center position. Here, the examiner performs alignment in the XY directions by moving the imaging unit 3 with respect to the subject's eye so that the alignment index K1 is positioned at the cross mark of the reticle LT. In the above description, the display control related to the alignment is performed in a state where the anterior segment image is displayed on the monitor 8, but the imaging is performed even in a state where the fundus image is displayed on the monitor 8 by a signal from the image sensor 38. Based on the signal from the element 65, the coordinate of the intermediate position K between the corneal apex position C and the pupil center position P is detected, and the alignment index K1 is electronically displayed at the position of the monitor 8 corresponding to the position. Also good.

  The second embodiment of the present invention will be described below. In the second embodiment, the control unit 80 determines a predetermined alignment reference point formed near an intermediate position between the corneal apex position and the pupil center position based on the position of the corneal apex and the pupil center detected as described above. , And the amount of alignment deviation between the detected position of the alignment reference point and the photographing optical axis L1 of the photographing optical system is calculated. Then, the control unit 80 drives and controls the XYZ driving unit 6 so that the alignment deviation amount satisfies a predetermined allowable range. More specifically, in the anterior ocular segment observation state as shown in FIGS. 4 and 5, the control unit 80 coordinates the intermediate position K between the corneal apex position C and the pupil center position P as shown in FIG. 7. Is detected, and a deviation amount Δd of the intermediate position K with respect to the alignment reference position O1 is obtained. Then, the control unit 80 automatically moves the photographing unit 3 in the XY directions so that the deviation amount Δd satisfies the allowable range A. Further, in the Z direction, the control unit 80 satisfies the predetermined aptitude working distance based on the amount of alignment deviation in the Z direction detected by the method as described in the first embodiment. Is moved in the Z direction.

  If the alignment state in the XYZ directions satisfies a predetermined alignment completion condition, the control unit 80 switches the display on the monitor 8 from the anterior ocular segment image to the fundus oculi image. In this case, the monitor 8 or the like may be notified that the anterior eye portion is switched to the fundus image. Then, after switching to the display of the fundus image, fine adjustment of the alignment is performed by the same operation as in the first embodiment, and a fundus image is captured. In this case, in the fundus observation state, automatic alignment may be operated using an allowable range wider than the above-described allowable range A.

FIG. 1 is an external configuration diagram of a fundus camera according to the present embodiment. 2 is a schematic configuration diagram of an optical system and a control system housed in a photographing unit 3. FIG. It is a figure explaining the presentation position of a fixation target. It is an example of the anterior ocular segment observation screen displayed on the display screen of the monitor when photographing the fundus center. It is an example of the anterior ocular segment image observation screen displayed on the monitor when photographing the fundus periphery. It is a figure at the time of a fundus image being displayed on the screen of a monitor. It is a figure explaining the detection method of the coordinate of the intermediate position K of the cornea vertex position C and the pupil center position P. FIG. It is an example of the anterior segment image observation screen displayed on the monitor when photographing the fundus periphery, and is an observation screen when the alignment index K1 is displayed electronically.

Explanation of symbols

3 Shooting unit (device main unit)
30 fundus observation / imaging optical system 8 display monitor 50 alignment index projection optical system 60 anterior ocular segment observation optical system 65 two-dimensional imaging device 70 fixation target presentation optical system 80 control unit C corneal vertex position P pupil center position K intermediate position Δd Alignment deviation amount A Alignment allowable range C1 Alignment index indicating corneal apex position P1 Alignment index indicating pupil center position K1 Alignment index indicating intermediate position LT reticle Ma to Md Alignment index image

Claims (5)

In a fundus camera having a photographing unit for arranging a fundus photographing optical system for photographing the fundus of a subject's eye,
Alignment light projection means for projecting an alignment beam onto the cornea of the subject's eye;
First detection means for detecting a corneal apex position by detecting corneal reflected light by the alignment light beam;
Imaging means for imaging the anterior segment of the subject's eye;
Second detection means for detecting a pupil center position based on a signal from the imaging means;
Guidance means for guiding the imaging unit based on a corneal apex position detected by the first detection means and a pupil center position detected by the second detection means;
A fundus camera comprising: The fundus camera of claim 1 comprises:
A display means capable of switching and displaying a fundus image and an anterior ocular segment image;
The guiding means electronically displays an alignment mark indicating the corneal apex and an alignment mark indicating the pupil center on the screen on which the anterior segment image is displayed by the display means based on the detection results of the first detection means and the second detection means. A fundus camera that displays images simultaneously. The fundus camera of claim 2,
A fixation target presenting means capable of changing the position of the fixation target for guiding the eye of the subject's eye;
The guide means electronically displays a reticle serving as a reference for performing alignment using the alignment mark, and the display shape of the reticle according to the fixation target presentation position changed by the fixation target presentation means A fundus camera characterized by changing the eye. The fundus camera of claim 1,
A position of a predetermined alignment reference point formed between the corneal apex position and the pupil center position based on the corneal apex position detected by the first detection means and the pupil center position detected by the second detection means. A reference point position detecting means for detecting,
The guiding means includes
A fundus camera characterized in that an alignment mark indicating the alignment reference point is electronically displayed on a screen on which an anterior segment image is displayed by the display unit based on a detection result of the reference point position detection unit. The fundus camera of claim 1,
Driving means for driving the imaging unit;
A position of a predetermined alignment reference point formed between the corneal apex position and the pupil center position based on the corneal apex position detected by the first detection means and the pupil center position detected by the second detection means. A reference point position detecting means for detecting,
The guiding means includes
Control means for controlling the drive means so that the alignment deviation amount between the position of the alignment reference point detected by the reference point position detection means and the imaging optical axis of the fundus imaging optical system satisfies a predetermined allowable range; A fundus camera comprising:

Images