JP4774304B2 - Fundus camera - Google Patents

Description

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

  In the fundus camera for photographing the fundus of the eye to be examined, the following is an example in which the examiner determines whether the alignment state of the apparatus main body with respect to the eye to be examined is appropriate with the fundus image displayed on the screen of the display monitor. What is known.

  As a representative example, an index light source for projecting an index toward the cornea surface of the eye to be examined is arranged around the hole of the hall mirror that is substantially conjugated with the pupil of the eye to be examined, and the fundus image of the eye to be examined is obtained. There is one that allows the examiner to determine the alignment state of the apparatus main body with respect to the eye to be examined from the position of the corneal bright spot (working dot image) by the index light source observed by the observation optical system to be observed (see, for example, Patent Document 1).

  In addition, an index light source for projecting the index toward the corneal surface of the eye to be examined is arranged so as to be coaxial with the optical axis of the imaging optical system, and a working dot image (corneal bright spot) by this is arranged in the fundus observation optical system. There is known a technique that allows an examiner to determine an alignment state of an apparatus main body with respect to an eye to be examined by imaging with a provided imaging element (see Patent Document 2). Further, in Patent Document 2, when photographing the peripheral part of the fundus, the display position of the mark indicating the alignment reference position is changed, and the fundus camera main body of the fundus camera main body is matched so that the changed alignment reference reticle matches the working dot image. Adjusting the position is disclosed.

Further, an index light beam is projected onto the eye cornea to be examined, and the cornea reflection image is detected by a sensor for detecting cornea reflection light to generate an alignment signal. An alignment mark based on this signal is electronically displayed on the display monitor together with the fundus image. Is known (see Patent Document 3).
JP 53-49890 A Japanese Patent Laid-Open No. 11-4808 Japanese Patent Laid-Open No. 3-15438

  By the way, in the case of a non-mydriatic retinal camera that uses natural mydriasis, appropriate alignment is performed for both central position shooting (standard shooting) and peripheral position shooting (peripheral shooting) (for example, the apex of the cornea matches the shooting optical axis) If the image is aligned in such a manner, it is difficult to obtain a good image in peripheral photographing because the photographing light beam is easily shielded (vignetted) by the iris of the eye to be examined. For this reason, in the case of peripheral photographing, there is a technique for avoiding vignetting of the photographing light flux by performing alignment so that the photographing optical axis passes through the center of the pupil of the eye to be examined.

However, in imaging of the peripheral part, when alignment is performed on the subject eye so that the pupil center and the imaging optical axis substantially coincide with each other, the alignment with respect to the subject eye is appropriate,
Since the working dot image does not coincide with the predetermined reticle, alignment adjustment is difficult. Further, even if the position of the reticle is changed on the screen of the display monitor, the position of the reticle changes every time the present position of the fixation target is changed, which is troublesome for the examiner. FIG. 17 is a diagram illustrating an example of a fundus oculi observation screen at the time of proper alignment when imaging is performed at the standard site and the peripheral site using the alignment method as described above with an apparatus such as Patent Document 1. . FIG. 18 is a diagram illustrating an example of a fundus oculi observation screen at the time of proper alignment when the standard part and the peripheral part are photographed using the alignment method as described above with an apparatus such as Patent Document 2. is there.

  In view of the above-described problems of the prior art, the present invention facilitates alignment adjustment while observing the fundus image of the eye to be examined even when the position of the fixation target presented to the eye to be examined is changed. An object of the present invention is to provide a fundus camera that can perform the above.

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

(1) An apparatus main body having a fundus observation optical system for observing the fundus oculi fundus and a fundus photographing optical system for photographing the eye to be examined, display means for displaying a fundus image of the eye to be examined, and fixation for guiding the eye of the subject eye In a fundus camera equipped with a fixation target presenting means capable of changing a target presentation position, alignment detection means for detecting an alignment state of the apparatus main body with respect to the subject's eye by imaging the anterior eye portion of the subject, and the fixation Alignment reference position acquisition means for acquiring an alignment reference position corresponding to the present presentation position of the fixation target changed by the sign presentation means, the alignment reference position acquired by the alignment reference position acquisition means, and the alignment detection means Calculating means for calculating an alignment deviation amount of the apparatus main body with respect to the eye to be examined based on the detection result from the eye, and a fundus observation image of the eye to be examined Display control means for electronically displaying an alignment index on the displayed screen of the display means and controlling the display of the alignment index based on the alignment deviation amount calculated by the calculation means. And
(2) In the fundus camera according to (1), the fixation target presenting unit may change a fixation target presentation position between a standard position for photographing the fundus center and a peripheral position for photographing the fundus periphery. It is a sign presentation means.
(3) In the fundus camera of (2), the display control means sets a reticle used as a reference for the alignment to a predetermined position on the screen of the display means regardless of the standard position and the peripheral position of the fixation target. It is characterized by being fixedly displayed on the screen.
(4) In the fundus camera of (3), a spot mirror having an illumination optical system for illuminating the fundus of the eye to be examined, a spot mirror obliquely provided in the optical path of the illumination optical system, and a lever for fixing the spot mirror to the tip A focus index projection optical system for projecting a focus index onto the eye to be examined via the eye, and the illumination light beam appearing on the screen of the display means is shielded by inserting the lever into the illumination optical system during fundus observation The reticle is displayed in a light shielding area.
(5) In the fundus camera of (1), the fixation target presenting unit changes the positional relationship between the eye to be examined and the apparatus main body to a right image shooting position and a left image shooting position of a pair of left and right stereo fundus images. It is a possible fixation target presenting means.
(6) In the fundus camera of (1), the apparatus main body has a projection optical system that projects an index light beam onto the anterior ocular segment to be examined, and the fundus observation optical system is an anterior ocular segment to be inspected by the projection optical system. Then, an optical alignment index is displayed on the screen of the display means by guiding the reflected image from an image pickup device provided in the fundus oculi observation optical system.
(7) The fundus camera according to (1) includes an index projection unit that projects an alignment index beam onto the anterior eye portion of the eye to be examined, and the alignment detection unit is received by an image sensor that images the anterior eye portion of the eye to be examined. A light receiving position of reflected light from the anterior segment of the alignment index light beam is detected.
(8) In the fundus camera according to (7), the calculation unit includes a calculation unit that calculates an alignment deviation amount in the up / down / left / right direction and the working distance direction of the apparatus main body with respect to the eye to be examined, and the display control unit includes the calculation The alignment index is moved on the screen of the display means based on the vertical and horizontal alignment deviation amounts calculated by the means, and the working distance is calculated based on the alignment deviation amount in the working distance direction calculated by the calculation means. Electronically displaying a second alignment index representing the amount of alignment deviation in the direction, and controlling the display so that the second alignment index is similar to the alignment index moving on the screen of the display means, To do.
(9) In the fundus camera according to (7), the calculation unit includes a calculation unit that calculates an alignment deviation amount in the vertical and horizontal directions of the apparatus main body with respect to the eye to be examined and a working distance direction, and the display control unit includes the calculation The alignment index is moved on the screen of the display unit based on the alignment deviation amount in the vertical and horizontal directions calculated by the unit, and the alignment is based on the alignment deviation amount in the working distance direction calculated by the calculation unit. Indices are displayed separately in at least two.
(10) In the fundus camera of (1), the calculation unit includes a calculation unit that calculates an alignment deviation amount in the vertical and horizontal directions of the apparatus main body with respect to the eye to be examined. The display control unit is calculated by the calculation unit. The alignment index is displayed at a position away from the reticle used as a reference when the alignment index is displayed even when the alignment deviation amount in the vertical and horizontal directions exceeds a predetermined allowable deviation amount. It is characterized by that.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where the presentation position of the fixation target shown to a to-be-tested eye is changed, alignment adjustment can be performed easily, observing the fundus image of a to-be-tested eye.

  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-right direction (X direction) and the front-back (working distance) direction (Z direction) relative to the base 1, and a three-dimensional direction relative 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 eye E by an XYZ drive unit 6 provided on the movable 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 drive 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, a focus index projection optical system 40, an alignment index projection optical system 50, an anterior ocular segment observation optical system 60, and a fixation target presentation optical system 70. Has been.

  <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, and the photographing optical system and the fundus observation optical system share the objective lens 25 and the optical system from the photographing aperture 31 to the imaging lens 33. . The photographing aperture 31 is disposed at a position substantially conjugate with the pupil of the 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, and once converged in the vicinity of the pupil of the eye E by the objective lens 25, then diffuses to illuminate the fundus of the eye to be examined.

  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.

  <Focus Index Projection Optical System> The focus index projection optical system 40 includes an infrared light source 41, a slit index plate 42, two declination prisms 43 attached to the slit index plate 42, a projection lens 47, and an illumination optical system 10. A spot mirror 44 is provided obliquely in the optical path. The spot mirror 44 is fixed to the tip of the lever 45 and is normally provided obliquely on the optical axis, but is retracted out of the optical path by rotation of the rotary solenoid 46 during photographing. The spot mirror 44 is arranged at a position conjugate with the fundus of the eye to be examined. The light source 41, the slit indicator plate 42, the H declination prism 43, the projection lens 47, the spot mirror 44 and the lever 45 are moved in the optical axis direction by the moving mechanism 49 in conjunction with the focusing lens 32. Further, the light flux of the slit index plate 42 of the focus index projection optical system 40 is reflected by the spot mirror 44 via the deflection prism 43 and the projection lens 47, and then the relay lens 21, the perforated mirror 22, the dichroic mirror 24, The light is projected onto the fundus of the eye E through the objective lens 25. When the fundus is out of focus, the index images S1 and S2 of the slit index plate 42 are separated and projected in agreement when in focus. Then, the focus index images S1 and S2 projected onto the fundus of the eye E are imaged together with the fundus image by the fundus observation imaging element 38 (see FIG. 8).

  <Alignment Index Projection Optical System> An alignment index projection optical system 50 that projects an alignment index light beam includes an infrared light source 51 and a collimating lens 52 that are symmetrically arranged in the left-right direction around the photographing optical axis L1. A first index projection optical system, and a second index projection optical system that is disposed symmetrically with respect to a vertical plane that has an optical axis that is arranged at a narrower angle than the first index projection optical system and that passes through the optical axis L1. And 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 eye E, and the second index projection optical system projects a finite index on the cornea of the 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 eye to be examined.

  <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. In addition, the alignment index projected onto the anterior segment is received by the two-dimensional imaging element 65 by turning on the light source of the alignment index projection optical system 50. 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 eye to be examined.

  As shown in FIG. 3, two infrared light sources 55 (center wavelength 880 nm) for forming an optical alignment index (working dot W1) on the cornea of the eye to be inspected are provided around the hole of the perforated mirror 22. They are arranged symmetrically about the optical axis L1. 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 disposed at a substantially conjugate position with the fundus when the working distance between the eye E to be examined 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 eye to be examined. 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. As shown in FIG. 4, the eight light shielding plates 71 are each provided with opening holes 71 a to 71 h. 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 is formed in the opening holes 71a to 71h as shown in FIG. Correspondingly, eight positions 81L, 81R and 82 to 87 are presented with respect to the optical axis L2. The initial rotation position of the disk plate 72 is detected by an optical sensor 77 having a light shielding plate 76 and a light projecting / receiving unit, and the control unit 80 uses pulses to place the opening holes 71a to 71h in front of the light source 74, respectively. The rotation angle of the motor 73 is controlled. The number of pulses for arranging the opening holes 71a to 71h in front of the light source 74 is stored in the control unit 80 in advance.

  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, and reaches the eye fundus. 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 81R corresponding to the opening hole 71b is used when photographing mainly in the vicinity of the posterior pole portion of the fundus including the right eye's macula and optic nerve head in a balanced manner. 81R is the standard position for right-eye photography. On the other hand, the fixation target position 81L corresponding to the opening hole 71a is used when photographing mainly in the vicinity of the posterior pole portion 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. Then, fixation target positions 82 to 87 corresponding to the opening holes 71c to 71h are set as positions for peripheral photographing. FIG. 5B is a diagram illustrating the state of the fundus image when the fixation target is photographed by changing the fixation target to the position 81R and the positions 82 to 87 in the right eye photographing, and regions 111R and 112 to 117 are respectively illustrated. It corresponds to position 81R and positions 82 to 87.

  <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. Note that the switch unit 84 includes a focus adjustment switch 84a for performing focus adjustment of the fundus image, a fixation target presentation switch 84b for changing the presentation position of the fixation target with respect to the eye to be examined, a stereoscopic photographing switch 84c, and the like. Has been placed.

  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.

  When photographing the fundus center, the examiner sets the fixation target presentation position for photographing the fundus center using the switch 84b. Here, the control part 80 arrange | positions the light-shielding plate 71 with the opening hole 71b in front of the light source 74, and makes a fixation target position the standard position (substantially center position) of a 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, as shown in FIG. 6A, four index images Ma, Mb, Mc, and Md also appear. At the center of the monitor 8 (the center of the screen), the control unit 80 electronically forms a reticle M and a circular mark P representing the smallest pupil diameter that can be photographed. Here, in the standard imaging alignment for imaging the center of the fundus (center of the posterior pole), as shown in FIG. 6 (b), the center of the reticle M in which the corneal apex of the eye to be inspected is a reference for alignment. The joystick 4 is operated so as to be positioned concentrically. In the front-rear direction (working distance direction), the photographing unit 3 is moved so that the index image is focused. At this time, the examiner confirms whether or not the pupil diameter of the eye to be examined is larger than the circular mark P representing the minimum pupil diameter.

When the four index images Ma to Md imaged by the two-dimensional image sensor 65 are input to the controller 80, the controller 80 sets the alignment reference position O ₁ ( For example, in the center imaging, the position where the corneal apex coincides with the imaging optical axis and the center position of the light receiving element is set as the alignment reference position O ₁ ), and the alignment detection result detected by these index images Based on this, an alignment deviation amount (positional deviation) of the apparatus main body with respect to the eye to be examined is calculated. The control unit 80 obtains an intermediate position C between the index images Ma and Mb, and obtains a deviation amount Δd ₁ with respect to the alignment reference position O _{1 in the} XY directions (see FIG. 7A). The intermediate position C can be regarded as the corneal apex position. Then, whether or not the alignment in the XY directions is appropriate is determined depending on whether or not the deviation amount Δd ₁ is within a predetermined allowable range A for completion of alignment for a certain period of time. Further, 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. Note that 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. Thus, the amount of alignment deviation in the working distance direction with respect to the eye to be examined is obtained (for details, refer to Japanese Patent Laid-Open No. 6-46999). Also in the Z direction, the amount of deviation with respect to the alignment reference position in the Z direction is obtained, and whether or not the alignment in the Z direction is appropriate is determined depending on whether the amount of deviation is within the allowable range for completion of alignment.

  Here, 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. The display can be switched between the anterior ocular segment image and the fundus oculi image of the monitor 8 by the switch operation of the switch unit 84. In the above operation, the imaging unit 3 may be automatically aligned with the eye to be examined by driving and controlling the XYZ driving unit 6 based on the alignment deviation amount calculated by the control unit 80 ( So-called auto alignment). In this case, the auto alignment may be executed until the alignment state in the XYZ directions satisfies a predetermined alignment completion condition.

  FIG. 8 is a screen example when the fundus image of the two-dimensional image sensor 38 is switched. When the alignment state is appropriately adjusted, the fundus image has two corneal reflection lights formed by the light source 55. An optical alignment index W1 (optical working dot) appears superimposed on the fundus observation image. FIG. 8A shows a screen example immediately after switching to the fundus image, and FIG. 8B shows a screen example after completion of fine adjustment. Here, reference numeral 145 denotes a light shielding area formed on the image sensor 38 by shielding the observation light beam by the lever 45 inserted in the optical path of the fundus illumination optical system 10. Note that focus index images S1 and S2 projected onto the fundus are formed at the tip (on the optical axis) of the light shielding region. In addition, you may make it provide the graphic display and LED lighting for alert | reporting to the examiner the present position of a fixation target.

  While viewing the fundus image (see FIG. 8A), the examiner matches the reticle M1 in which the optical alignment index W1 is formed electronically (electrically) symmetrically with respect to the center of the screen of the display monitor 8. As described above, the fine adjustment of the alignment in the XY directions is performed, and the fine adjustment of the alignment in the Z direction is performed so that the optical alignment index W1 is focused on the screen. Furthermore, the alignment state is further finely adjusted by operating the joystick 4 so that the flare etc. of the fundus image can be confirmed and photographing can be performed in a desired state.

Further, in the present embodiment, alignment can be performed without using the optical alignment index W1. W2 shown in FIG. 8 is an electronic alignment index (electronic working dot) electronically displayed (superimposed) by the control unit 80, and the alignment deviation of the imaging unit 3 with respect to the eye to be calculated is calculated as described above. The display is controlled based on the quantity. M2 is a reticle that is electronically displayed on the screen of the display monitor 8 and used as a reference for alignment, and is fixedly displayed at a predetermined position on the screen. In the present embodiment, the alignment index W2 is calculated based on the deviation amount Δd ₁ with respect to the alignment reference position O _{1 in} the X and Y directions calculated as described above and the formation position of the reticle M2 electronically formed on the monitor 8. Control the display position. Note that the reticle M2 is fixedly displayed at a predetermined position on the screen of the monitor 8 regardless of whether the fixation target presentation position is the standard position or the peripheral position. Further, the reticle M2 may be formed anywhere on the screen as long as it is a position that can be visually recognized when performing alignment adjustment. In this embodiment, in order to facilitate fundus observation, avoid the center of the screen, It is formed in a shielding area slightly below the center of the screen.

In addition, the control unit 80 determines the position (display position) of the electronic alignment index W2 with respect to the reticle M2 based on the deviation amount Δd ₁ that changes as the apparatus main body moves relative to the eye to be examined in the XY direction. Sequentially correct and display again. For this reason, the examiner can finely adjust the alignment of the apparatus main body with respect to the eye to be examined in the XY directions by moving the apparatus main body in the XY directions so that the electronic alignment index W2 and the reticle M2 coincide with each other (FIG. 8 (b)).

  Reference numeral 100 denotes an indicator (alignment bar) electronically displayed by the control unit 80, which is an alignment target used to express the amount of alignment deviation in the working distance direction (Z direction) with respect to the eye to be examined. In the present embodiment, the control unit 80 performs display control of the number of indicators displayed based on the deviation amount with respect to the alignment reference position in the Z direction calculated as described above. In this case, display control is performed so that the indicator is extended upward with respect to the indicator 101a if there is a misalignment in the forward direction, and the indicator is displayed so as to extend downward with respect to the indicator 101a if there is a misalignment in the back direction. It is possible to control. Here, the examiner performs fine adjustment of the alignment of the apparatus main body in the Z direction with respect to the subject's eye by moving the apparatus main body in the Z direction so that only the indicator 101a is displayed (see FIG. 8B). .

  In the present embodiment, the optical alignment index W1 is used by displaying the optically generated optical alignment index W1 and the electronically generated electronic alignment index together with the fundus image. Fine adjustment of the alignment in the XY direction with respect to the eye to be examined can be performed, and fine adjustment of the alignment in the Z direction with respect to the eye to be examined can be performed using a change in the degree of blur of the optical alignment index W1.

  According to the above configuration, even when the alignment deviation amount in the X and Y directions calculated by the control unit 80 exceeds a predetermined allowable deviation amount, the position is away from the reticle M2. It is also possible to display the electronic alignment index W2. FIG. 9 is an example of a screen when the apparatus main body is displaced downward with respect to the eye to be examined during fundus observation. In this case, the optical alignment index W1 has disappeared from the display monitor 8 because the displacement amount due to the misalignment is large. In such a case, for example, by causing the control unit 80 to display the electronic alignment index W2 in the vicinity of the lower edge of the display monitor 8, the examiner shifts the alignment downward while observing the fundus image. I can confirm that. Here, when the examiner moves the apparatus main body upward using the joystick 4, the alignment can be adjusted while observing the fundus image. In other words, in the present embodiment, it is possible to detect misalignment information with respect to the anterior segment of the subject's eye even during fundus observation using the dedicated imaging element 65 for capturing the anterior segment image. Therefore, by using this detection result, the electronic alignment index W2 is displayed near the edge on the display screen of the display monitor 8 so as to correspond to a large misalignment in the XY direction, so that the fundus image is observed while observing the fundus image. It is possible to correct a large misalignment. If the amount of deviation is large even in the alignment in the Z direction, the optical alignment index W1 disappears from the display monitor 8. However, using the detection result of the alignment deviation information in the Z direction with respect to the anterior segment of the eye to be examined, Z When a large misalignment in the direction is detected, this is expressed by the indicator 100, whereby it is possible to correct the large misalignment in the Z direction while observing the fundus image.

  Next, focus adjustment of the fundus image is performed. In this case, the examiner performs focus adjustment by manual operation by operating the focus adjustment switch 84a while viewing the fundus image displayed on the monitor 8. Based on an input signal from the focus switch 84a, the control unit 80 drives the moving mechanism 49 to move the focusing lens 32 back and forth. If the desired part can be observed well, imaging is executed by pressing the imaging switch 4b. The controller 80 drives the insertion / removal mechanism 39 to detach the flip-up mirror 34 from the optical path, and drives the insertion / removal mechanism 66 to cause the dichroic mirror 24 to detach from the optical path and to emit the imaging light source 14. At this time, a fundus image is captured by the two-dimensional image sensor 35 and the captured image data is stored in the memory 85. Then, the control unit 80 switches the display screen of the monitor 8 to a color fundus image captured by the two-dimensional image sensor 35.

  Next, a case where the fundus periphery of the eye to be examined is imaged will be described. In this case, the examiner sets the presenting position of the fixation target to an arbitrary presenting position for the fundus periphery by using the switch 84b. In the case of peripheral shooting, the line of sight is guided in the direction of the fixation target for peripheral shooting. For this reason, in a state where alignment is performed so as to be suitable for peripheral imaging (for example, alignment is performed so that the vicinity of the center of the pupil of the eye to be inspected matches the imaging optical axis L1), the optical alignment index W1 in the fundus observation image and The position of the index image detected by the anterior ocular segment observation is also shifted from the position of the standard photographing (substantially central photographing) (see FIGS. 10 and 11).

Here, a case will be described in which an opening hole 71f is arranged in front of the light source 74 by the switch 84b to capture an area 115 centered on the nipple in the right eye as shown in FIG. At this time, even if an appropriate alignment state is maintained, the light receiving positions of the index images Ma, Mb, Mc, and Md imaged by the imaging element 65 of the anterior segment imaging optical system are standard as shown in FIG. The state is shifted from the state of shooting (center shooting). Therefore, in the present embodiment, when imaging the fundus periphery by performing alignment so that the imaging optical axis L1 passes in the vicinity of the center of the pupil of the eye to be examined as described above, the change in the line-of-sight direction of the eye to be examined is performed. Considering this, the alignment reference position used as a reference when calculating the amount of alignment deviation based on the anterior segment image is changed according to the fixation target presentation position to calculate the alignment deviation with respect to the eye to be examined. In FIG. 11, O ₁ is an alignment reference position at the time of standard photographing, and O ₂ is an alignment reference on the image sensor 65 when photographing the region 115 shown in FIG. The position is shown, and is at a position shifted by ΔD with respect to the alignment reference position O ₁ . That is, the control unit 80 calculates the alignment deviation of the apparatus main body with respect to the eye to be inspected by imaging the anterior eye part, and the corneal apex of the eye to be inspected is set to the alignment reference position set for each change in the fixation target presentation position. In order to detect that the alignment is appropriate when positioned, an offset process is applied to the calculation of the alignment deviation amount.

  In such a case, alignment reference positions are set in advance and stored in the memory 85 so as to correspond to the respective fixation target presentation positions (82 to 87) when photographing the fundus periphery. Then, the control unit 80 acquires the alignment reference position corresponding to the current presentation position of the fixation target from the memory 85 in which the alignment reference positions are stored as described above.

  The alignment reference position information stored in the memory 85 is set as one, and the alignment reference position corresponding to the changed fixation target presentation position is obtained by a predetermined calculation according to the different fixation target presentation positions, It can also be acquired. By using such a method, the alignment reference position can be obtained even when the fixation target presentation position is arbitrarily selected using a mechanism that arbitrarily moves the fixation target presentation position vertically and horizontally. it can.

  When the alignment reference position corresponding to the fixation target presentation position is set, the alignment reference is set so that the photographing optical axis L1 is positioned at a position where the desired fundus image can be properly photographed when the fine alignment adjustment is completed. What is necessary is just to set a position. In photographing the fundus center, for example, a point where the optical axis L1 of the photographing optical system intersects with the image pickup surface of the image pickup element 65 may be used as the alignment reference position in the XY direction. On the other hand, in photographing the fundus periphery, when the alignment is completed, the fundus image at a position desired by the examiner can be observed, and the photographing optical axis L1 is at a position where the vignetting of the observation light beam by the pupil is within the allowable range. The alignment reference position may be set so that is positioned.

Therefore, the control unit 80 acquires the alignment reference position corresponding to the present fixation target presenting position (opening hole 71 f) from the memory 85, and the alignment detection result detected by the acquired alignment reference position and the control unit 80. Based on the above, an alignment deviation amount of the apparatus main body with respect to the eye to be examined is calculated. That is, the control unit 80 obtains a deviation amount (a positional deviation) with respect to a new alignment reference position O ₂ that is determined when the region 115 in FIG. 5 is captured based on the four index images captured by the image sensor 65. ) Here, the control unit 80 obtains an intermediate position C between the index images Ma and Mb, and obtains a deviation amount Δd2 with respect to the alignment reference position O _{2 in the} XY direction (see FIG. 7B). Then, whether or not the alignment in the XY directions is appropriate is determined based on whether or not the deviation amount Δd2 is within a predetermined allowable range A for completion of alignment for a certain period of time. Also, with respect to the Z direction, a deviation amount with respect to the alignment reference position in the Z direction is obtained, and whether or not the alignment in the Z direction is appropriate is determined based on whether or not the deviation amount is within an allowable range for completion of alignment for a certain period of time.

  When the examiner first performs alignment in the anterior segment display state, for example, the examiner operates the joystick 4 so that the pupil center of the eye to be examined is positioned concentrically with the center of the reticle M.

  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.

  FIG. 12 is an example of a screen when the fundus image obtained by the two-dimensional image sensor 38 is switched, and shows a state where the alignment state is appropriate to some extent.

In the electronic alignment index W2, the control unit 80 controls the display position of the electronic alignment index W2 based on the alignment deviation amount Δd2 with respect to the alignment reference position O ₂ when photographing a predetermined region 115 in the fundus peripheral portion. That is, when the deviation amount Δd2 with respect to the alignment reference position O ₂ for photographing the fundus region 115 is detected within the allowable range, the control unit 80 detects the deviation amount Δd2 with respect to the reticle M2 that is fixedly displayed. The electronic alignment index W2 is electronically displayed at a position on the screen considering the above.

  The examiner adjusts the alignment in the XY directions so that the electronic alignment index W2 and the reticle M2 coincide with each other in the same manner as the alignment operation at the time of the above-described central photographing, thereby aligning the alignment of the apparatus main body with respect to the eye to be examined in the XY directions. Fine adjustments can be made (see FIG. 10).

  Further, the control unit 80 expresses the misalignment in the Z direction by the indicator 100 on the monitor 8, so that the examiner adjusts the alignment in the Z direction so that only the indicator 101 a is displayed. It is possible to finely adjust the alignment of the apparatus main body in the Z direction (see FIG. 10).

  When fine alignment adjustment is completed by such an operation, focus adjustment of the fundus image is performed. If the desired part can be observed well, imaging is executed by pressing the imaging switch 4b. The controller 80 drives the insertion / removal mechanism 39 to detach the flip-up mirror 34 from the optical path, and drives the insertion / removal mechanism 66 to cause the dichroic mirror 24 to detach from the optical path and to emit the imaging light source 14. The display on the monitor 8 is switched by the control unit 80 to a color fundus image photographed by the two-dimensional image sensor 35.

  With the configuration described above, alignment adjustment can be easily performed while observing the fundus image of the eye to be inspected even when photographing the fundus periphery.

  In the above description, the alignment deviation in the working distance direction is expressed by the indicator 100 fixedly displayed on the focus bar in the alignment adjustment in the Z direction while observing the fundus image. However, it is not limited to this. As another method, an alignment index for expressing the amount of alignment deviation in the Z direction is electronically displayed, and is associated with an electronic alignment index W2 that moves on the monitor 8 in order to express an alignment shift in the XY direction. Such display control can be considered. In this way, when checking the alignment deviation in the XY directions by the positional relationship between the electronic alignment index W2 and the reticle M2, the examiner can check the alignment deviation in the Z direction without moving the line of sight. The examiner can smoothly and quickly finely adjust the alignment in the three-dimensional direction. An example is shown below.

  For example, the electronic alignment index W2 that moves on the monitor 8 based on the amount of alignment deviation in the Z direction calculated by the control unit 80 may be displayed separately in at least two (see FIG. 13). . In this case, display control of the separation degree of the two electronic alignment indexes W2a and W2b is performed according to the alignment deviation amount in the Z direction, and the two separated when the deviation amount in the Z direction alignment deviation is within an allowable range. It is conceivable that the electronic alignment indices W2a and W2b are matched and displayed as one electronic alignment index W2. Further, according to the amount of alignment deviation in the Z direction, one of the two electronic alignment indexes W2a and W2b displayed separately may be enlarged and the other may be reduced.

  Further, display of the degree of blur of the electronic alignment index W2 may be controlled according to the amount of alignment deviation in the Z direction. That is, the display control of the electronic alignment index W2 is performed in the same manner as the degree of blur of the optical alignment index W1 changes according to the change of the working distance with respect to the eye to be examined. In this case, it is conceivable to display and control the brightness and size of the electronic alignment index W2 in accordance with the amount of alignment deviation in the Z direction. In this case, when the amount of alignment deviation in the Z direction is large, the brightness of the electronic alignment index W2 is reduced and the diameter of the electronic alignment index W2 is increased. When the amount of alignment deviation in the Z direction is small, it is conceivable to increase the brightness of the electronic alignment index W2 and decrease the diameter of the electronic alignment index W2.

  Moreover, it is good also as a structure by which the alignment parameter | index like the above-mentioned indicator 100 is displayed near the electronic alignment parameter | index W2 which moves on the monitor 8 (refer FIG. 14). That is, the control unit 80 controls the number of indicators displayed so as to be associated with the electronic alignment index W2 in accordance with the amount of alignment deviation in the Z direction. In this case, if there is a misalignment in the front direction, display control is performed so that the indicator 102 extends downward with respect to the electronic alignment index W2, and if there is a misalignment in the back direction, the indicator 103 is moved upward with respect to the indicator 101a. It may be possible to control the display so as to extend. Then, display control can be considered such that when the alignment deviation in the Z direction falls within an allowable range, the indicators 102 and 103 are erased from the screen and the electronic alignment index W2 is displayed. In this way, when the examiner confirms the alignment deviation in the XY direction based on the positional relationship between the electronic alignment index W2 and the reticle M2, the examiner determines whether the alignment deviation in the Z direction is the forward direction or the backward direction. Since it can also be confirmed, the examiner can finely adjust the alignment in the three-dimensional direction more smoothly and quickly.

  Further, the control unit 80 may change the color of the electronic alignment index W2 that moves on the monitor 8 based on the calculated amount of alignment deviation in the Z direction. In this case, when the amount of alignment deviation in the Z direction is large, the color of the electronic alignment index W2 is gray, and when the misalignment in the Z direction is within the allowable range, the color of the electronic alignment index W2 is white. Such display control can be considered.

  In the above description, the optical alignment index W1 generated optically and the electronic alignment index W2 generated electronically are displayed together with the fundus image. However, the present invention is not limited to this. The alignment deviation amount with respect to the eye to be examined at the time of fundus observation may be expressed only by display control of the electronic alignment index W2. In addition, the optical alignment index light source 55 is turned on when the position of the fixation target presented to the eye to be examined is for photographing the central part of the fundus, and the light source 55 is turned off for photographing the peripheral part. It is also good.

  In the above description, since the electronic alignment index W2 reticle M2 and the indicator are displayed on the light shielding area by the lever 45 displayed on the monitor 8, these displays obstruct the fundus observation. Can be avoided. Further, since the light shielding region 145 is displayed in black, the reticle M2 is easy to see. In addition, it is not restricted to said display position, For example, displaying on the mask displayed on the monitor 8 is also considered.

  In the above description, the index projection optical system 50 for projecting the alignment index light beam to the anterior eye part to be examined is provided, and the image of the alignment index light beam received by the image sensor 65 for imaging the anterior eye part to be examined is received. Although the configuration is such that the alignment state of the apparatus main body with respect to the eye to be examined is detected by detecting the light receiving position of the reflected light from the anterior optometry part, the present invention is not limited to this. For example, the alignment state of the apparatus main body with respect to the eye to be examined may be detected by extracting the pupil center of the eye to be examined by image processing from the position of the pupil imaged by the image sensor 65 and the light amount level. In this case, the alignment reference position may be kept constant regardless of the change in the fixation target presentation position, and the alignment deviation amount may be detected. Note that the present invention can also be applied to the case where stereoscopic imaging of the fundus of the eye to be examined is performed. In stereoscopic imaging, the main body of the apparatus is moved to the left and right by a predetermined amount (for example, 1 mm from the center to the left and right respectively), and a pair of left and right stereoscopic fundus images are captured to display the fundus image in a stereoscopic manner. The fundus image can be acquired. In this case, since the image is taken with the apparatus main body shifted to the right or left with respect to the eye to be examined, the line-of-sight direction of the eye to be examined guided by the fixation target is shaken to the left and right. . Therefore, the alignment reference position for photographing the fundus image by shifting the apparatus main body to the right with respect to the eye to be examined and the alignment reference position for photographing the fundus image by shifting the apparatus main body to the left with respect to the eye to be examined, respectively. It is stored in the memory 85. In this case, the alignment reference position when the apparatus main body is shifted to the right with respect to the eye to be examined (right image capturing position) is shifted leftward with respect to the alignment reference position for standard imaging. In addition, the alignment reference position when the apparatus main body is shifted to the left with respect to the eye to be examined (imaging position in the left image) is shifted to the right with respect to the alignment reference position in standard imaging.

  The operation will be briefly described below (see FIG. 15). In this case, the fixation target presentation position is set for central photographing. First, alignment adjustment is performed by the same procedure as the above-described photographing of the fundus center until the reticle M2 and the electronic alignment index W2 match as shown in FIG. When the alignment adjustment is completed and the three-dimensional imaging switch 84c is pressed by the examiner, the control unit 80 shifts the alignment reference position for standard imaging to the right side to capture the fundus image. Change to Thereby, the control unit 80 calculates the alignment displacement amount in the XY directions based on the changed alignment reference position, and controls the display position of the electronic alignment index W2 based on the displacement amount. FIG. 15A is a display screen of the monitor 8 when the stereoscopic shooting switch 84c is pressed. Here, the examiner moves the apparatus main body to the right side with respect to the eye to be examined so that the working dots W2 are accommodated in the reticle M2 while looking at the monitor 8. When the alignment adjustment is completed in this way, fundus photographing is performed by pressing the photographing button 4b. When the photographing is completed, the control unit 80 changes the alignment reference position to the alignment reference position for photographing the fundus image by shifting the apparatus main body to the left side. Thereby, the control unit 80 calculates the alignment displacement amount in the XY directions based on the changed alignment reference position, and controls the display position of the electronic alignment index W2 based on the displacement amount. FIG. 15B is a display screen of the monitor 8 immediately after the fundus image is taken by shifting the apparatus main body to the right side. Here, the examiner moves the apparatus main body to the left side with respect to the subject's eye so that the electronic alignment index W2 is within the reticle M2 while looking at the monitor 8, and performs imaging when the alignment is completed. With the configuration as described above, alignment adjustment can be easily performed while observing the fundus image of the eye to be examined even when performing stereoscopic imaging of the fundus.

  Note that when the electronic alignment index W2 is moved on the monitor 8 based on the calculated vertical and horizontal alignment deviation amounts, the control unit 80 expresses changes in the vertical and horizontal alignment deviation amounts that change over time. For this purpose, the electronic alignment index W2 may be displayed as an afterimage (see FIG. 16). In this case, the control unit 80 calculates the alignment deviation calculated a predetermined time before the calculation of the current alignment deviation amount calculated in real time (0.2 seconds, 0.4 seconds, 0.6 seconds, etc.). The amount is stored in the memory 85, and the electronic alignment index W2 is displayed at the display position on the monitor 8 corresponding to the stored alignment deviation amount before a predetermined time, and the monitor according to the current alignment deviation amount. It is conceivable that the electronic alignment index W2 is displayed at the display position on the display 8. In this way, the examiner can confirm the temporal change in the amount of alignment deviation in the vertical and horizontal directions from the monitor 8, so that the movement of the eye to be examined can be easily grasped and the fundus image is observed. However, it is possible to easily perform alignment.

  In the above description, when display control of an electronic alignment index electronically displayed based on the alignment deviation amount calculated by the control unit 80 is performed, the display setting of the alignment index (color, brightness, shape) By displaying the optical alignment index (optical working dot W1) in a pseudo manner as displayed on the screen of the display monitor 8, the examiner is displayed electronically. Even with an electronic alignment index, alignment adjustment can be performed without a sense of incongruity. The electronic alignment index displayed electronically is not limited to this, and the display setting of the alignment index can be arbitrarily set.

It is an external appearance block diagram of the fundus camera which concerns on this embodiment. It is a schematic block diagram of the optical system and control system accommodated in an imaging | photography part. It is a figure explaining the structure around the hole of a perforated mirror. It is a figure explaining the structure of a light-shielding plate. It is a figure which shows the presentation position of a fixation target, and the fundus imaging position corresponding thereto. It is a figure when the anterior eye part to be examined is displayed on the screen of the display monitor. It is a figure explaining calculation of the amount of alignment deviation of the device main part to the eye to be examined. It is an example which shows the fundus observation screen in standard imaging. It is an example of a screen when the apparatus main body has shifted downward with respect to the eye to be examined during fundus observation. It is a figure when alignment is performed appropriately in peripheral photographing. It is a figure explaining the state which the position of the index image on the to-be-examined eye part shifted | deviated in periphery imaging | photography. It is a screen example of a fundus observation screen when switched to a fundus image, and shows a state in which the alignment state is made appropriate to some extent. It is a figure in the case of separating and displaying the electronic alignment parameter | index which moves on a monitor based on the amount of alignment deviation of a Z direction into at least 2 or more. It is a figure in case an alignment parameter | index like an indicator is displayed near the electronic alignment parameter | index which moves on a monitor. It is a figure which shows the fundus observation screen in the case of performing stereoscopic photography. It is a figure in the case of displaying an afterimage display of an electronic alignment index. It is a figure which shows an example of the fundus observation screen at the time of alignment appropriate in the case where imaging is performed at the standard part and the peripheral part using the alignment method as described above with an apparatus such as Patent Document 1. It is a figure which shows an example of the fundus oculi observation screen at the time of alignment appropriate when imaging | photography of a standard site | part and a peripheral site | part is performed using the above alignment methods with apparatuses like patent document 2. FIG.

Explanation of symbols

3 Shooting unit (device main unit)
DESCRIPTION OF SYMBOLS 8 Display monitor 10 Fundus illumination optical system 30 Fundus observation / imaging optical system 38 Image sensor 45 Lever 50 Alignment target projection optical system 55 Light source 60 Anterior eye observation optical system 65 Two-dimensional image sensor 70 Fixation target presentation optical system 80 Control Part 145 Shielding area O ₁ Alignment reference position for standard imaging Δd ₁ Alignment deviation amount O ₂ Alignment reference position for peripheral imaging Δd ₂ Alignment deviation amount C Corneal apex position W1 Optical alignment index W2 Electronic alignment index M2 Reticle M3 mark

Claims (10)

An apparatus main body having a fundus observation optical system for observing the fundus oculi observation eye and a fundus photographic optical system for photographing the eye to be examined, a display means for displaying a fundus image of the eye to be examined, and a fixation target for guiding a gaze of the eye to be examined A fundus camera comprising: a fixation target presenting means capable of changing a position;
An alignment detection means for detecting an alignment state of the apparatus main body with respect to the eye to be examined by imaging the anterior eye portion of the eye to be examined;
Alignment reference position acquisition means for acquiring an alignment reference position corresponding to the current presentation position of the fixation target changed by the fixation target presentation means;
Calculation means for calculating an alignment deviation amount of the apparatus main body with respect to the eye to be examined based on the alignment reference position acquired by the alignment reference position acquisition means and the detection result from the alignment detection means;
Display control means for electronically displaying an alignment index on the screen of the display means on which the fundus observation image of the eye to be examined is displayed, and controlling the display of the alignment index based on the alignment deviation amount calculated by the calculation means And a fundus camera. 2. The fundus camera according to claim 1, wherein the fixation target presenting means is capable of changing a fixation target presenting position between a standard position for photographing the fundus central part and a peripheral position for photographing the fundus peripheral part. A fundus camera characterized by 3. The fundus camera according to claim 2, wherein the display control means fixedly displays a reticle used as a reference for performing the alignment at a predetermined position on the screen of the display means regardless of a standard position and a peripheral position of the fixation target. A fundus camera characterized by 4. The fundus camera according to claim 3, further comprising: an illumination optical system that illuminates the fundus of the eye to be examined; a spot mirror that is obliquely provided in the optical path of the illumination optical system; and a lever that fixes the spot mirror to the tip. A focus index projection optical system for projecting a focus index onto the eye to be examined is provided in a light shielding area where the illumination light beam appearing on the screen of the display means is shielded by inserting the lever into the illumination optical system during fundus observation. A fundus camera in which the reticle is displayed. 2. The fundus camera according to claim 1, wherein the fixation target presenting means can change a positional relationship between the eye to be examined and the apparatus main body to a right image shooting position and a left image shooting position of a pair of left and right stereo fundus images. A fundus camera characterized by being a target presentation means. 2. The fundus camera according to claim 1, wherein the apparatus main body has a projection optical system that projects an index light beam onto the anterior ocular segment to be examined, and the fundus observation optical system is a reflected image from the anterior ocular segment to be examined by the projection optical system. A fundus camera characterized in that an optical alignment index is displayed on the screen of the display means by guiding the lens to an image sensor provided in the fundus observation optical system. The fundus camera of claim 1 has an index projection means for projecting an alignment index beam onto the anterior eye portion of the eye to be examined,
The fundus camera characterized in that the alignment detection means detects a light receiving position of reflected light from the anterior segment of the alignment index light beam received by an image sensor that images the anterior segment of the eye to be examined. The fundus camera according to claim 7, wherein the calculation means includes calculation means for calculating an alignment deviation amount in the working distance direction of the apparatus body with respect to the eye to be examined.
The display control means moves the alignment index on the screen of the display means based on the vertical and horizontal alignment deviation amounts calculated by the calculation means,
Based on the alignment deviation amount in the working distance direction calculated by the calculating means, a second alignment index representing the alignment deviation amount in the working distance direction is electronically displayed, and the second alignment index is displayed on the display means. A fundus camera, characterized in that display control is performed so as to follow the alignment index moving on the screen. The fundus camera according to claim 7, wherein the calculation means includes calculation means for calculating an alignment deviation amount in the working distance direction of the apparatus body with respect to the eye to be examined.
The display control means moves the alignment index on the screen of the display means based on the vertical and horizontal alignment deviation amounts calculated by the calculation means,
A fundus camera, wherein the alignment index is separated into at least two and displayed based on the alignment deviation amount in the working distance direction calculated by the calculating means. The fundus camera according to claim 1, wherein the calculation means includes calculation means for calculating an alignment deviation amount in the vertical and horizontal directions of the apparatus main body with respect to the eye to be examined.
The display control means is provided on a reticle used as a reference for displaying the alignment index even when the alignment deviation amount in the vertical and horizontal directions calculated by the calculation means exceeds a predetermined allowable deviation amount. A fundus camera, wherein the alignment index is displayed at a position away from the fundus camera.

Images