JP4492854B2 - Fundus camera - Google Patents

Description

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

In a fundus camera, an illumination light beam that illuminates the fundus of the subject's eye is formed into a ring-shaped light beam by a ring slit arranged at a position substantially conjugate with the pupil of the subject's eye, and is incident on the subject's eye from the periphery of the pupil, and from the center of the pupil to the fundus The reflected light is taken out for observation or shooting. Also, in the fundus camera, in order to suppress the occurrence of ghosts and flares due to the reflected light from the cornea, etc., the size of the light shielding point corresponding to the inner diameter of the ring slit arranged in the illumination optical system corresponds to the size of the pupil diameter. There has been proposed an aperture that is variable and further changes the aperture for limiting the shootable range in conjunction with the size of the light shielding point (see, for example, Patent Document 1).
JP-A-5-199997

  However, the fundus camera of the above prior art has a problem that the examiner has to judge the pupil diameter and switch manually, and there is a problem that the diaphragm mechanism for limiting the photographing range becomes complicated. Also, when photographing the periphery of the fundus, since the eyeball tilts, the image formation performance of the ring slit is inferior to that of the center of the rear pole, so flare and ghosting are likely to occur. However, no response was taken into account.

  The present invention has been made in view of the above prior art, and an object of the present invention is to provide a fundus camera capable of obtaining a good fundus image according to the size of the pupil region of the eye to be examined without complicating the apparatus configuration. . It is another object of the present invention to provide a fundus camera capable of obtaining a good fundus image even when photographing the periphery of the fundus.

(1) An alignment index projection optical system that projects an alignment index toward the cornea of the eye to be examined , an illumination optical system that illuminates the fundus of the eye to be examined, and a fundus illuminated by the illumination optical system is photographed by an imaging device. an imaging optical system, and a display means for displaying the fundus image captured by the imaging device, the fundus camera for photographing a fundus aligns with the subject's eye using a corneal reflection image, an eye to be examined A determination means for setting a predetermined determination range centered on the imaging optical axis located on the pupil of the subject eye and determining whether or not the pupil edge of the subject eye photographed is located in the determination range; and the pupil of the subject eye and the inner diameter changing means for changing on the basis of the inner diameter of the ring slit provided in the illumination optical system to form an illumination light beam of the ring-shaped in a substantially conjugate position to the determination result of the determination means, by the inner diameter changing means Further been based on an inner diameter information of the ring slit, characterized in that it comprises, a mask changing means for changing the mask size of electronically limit the display area of the fundus image displayed on the display means.
(2) In a fundus camera including an illumination optical system that illuminates the fundus of the subject's eye and an imaging optical system that captures an image of the fundus illuminated by the illumination optical system, a fundus image captured by the imaging element is displayed. Display means, a ring slit with a variable inner diameter provided in the illumination optical system to form a ring-shaped illumination light beam at a position substantially conjugate with the pupil of the eye to be examined, and an inner diameter variable means for changing the inner diameter of the ring slit A fixation target presenting means capable of changing a fixation target presentation position for guiding the eye direction of the subject's eye, a reference position for photographing around the vicinity of the posterior pole of the fundus and a peripheral position for photographing the fundus periphery A fixation target presenting means capable of changing the fixation target presentation position, and a fixation direction in which the visual line direction of the subject eye is detected or detected by the fixation target presentation of the fixation target presentation means. Information on the target presentation position The display area of the fundus image displayed on the display means based on the gaze detection / input means to be input, the inner diameter information of the slit by the inner diameter variable means and the detection result or the input result by the gaze detection / input means And a mask changing means for changing the mask size to be limited to .

  According to the present invention, a good fundus image without flare can be obtained according to the size of the pupil region of the eye to be examined without complicating the apparatus configuration. In addition, a good fundus image can be obtained also when photographing the periphery of the eye to be examined.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a non-mydriatic retinal camera according to an embodiment.

  The fundus camera includes a base 1, a movable base 2 that can be moved in the left and right direction (X direction) and the front and rear direction (Z direction) with respect to the base 1 by operating the joystick 4, An imaging unit 3 that can be moved three-dimensionally in the vertical and front-rear directions (Z direction) and a face support unit 5 that is fixed to the base 1 to support the face of the subject. Reference numeral 6 denotes a Y drive unit that moves the photographing unit 3 in the vertical direction, and reference numeral 7 denotes an XZ drive unit that moves the photographing unit 3 back and forth. The XZ drive unit 7 arranges a Z table movable in the Z direction on the Y table, arranges an X table movable in the X direction on the Z table, and arranges the photographing unit 3 on the X table. Then, the photographing unit 3 is moved in the XY directions by driving the Z table and the X table by motors. The Y drive unit 6 moves the photographing unit 3 in the Y direction by driving the Y table up and down by a motor. This type of three-dimensional drive mechanism can be a known mechanism. The photographing unit 3 is moved up and down by the Y drive unit 6 being operated by rotating the joystick 4. A monitor 8 for displaying an observation image or a photographed image is provided on the examiner side of the photographing 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 optical system 70. ing.

  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 large ring slit 17a having a ring-shaped opening, a relay lens 18, a mirror 19, a black spot plate 20 having a black spot at the center, a relay lens 21, A perforated mirror 22 and an objective lens 25 are provided. The large ring slit 17a is provided at a conjugate position with the eye pupil to be examined. Further, the large ring slit 17a is disposed so as to be replaceable by a small ring slit 17b in which the inner diameter of the ring-shaped light beam is smaller than that of the large ring slit 17a by driving the solenoid 26. The small ring slit 17b is used to increase the luminous flux passing through the pupil when the eye to be examined is a small pupil. In this embodiment, the ring slit having a variable inner diameter is selectively switched from one having a different inner diameter. However, the ring slit itself is one, and the size of the light-shielding point placed at the conjugate position with the crystalline lens. Configurations that change the height are also included.

  The observation illumination optical system is arranged between 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 condenser lens 13 and a ring slit 17a (17b). The optical system from the dichroic mirror 16 and the ring slit 17a (17b) to the objective lens 25 is provided. The dichroic mirror 16 has a characteristic of reflecting infrared light and transmitting visible light.

  The fundus oculi observation / imaging 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, an imaging lens 33, infrared light reflection, and visible light. A dichroic mirror 34 having transmission characteristics 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 39 including a motor. In the transmission direction of the dichroic mirror 34, a color CCD camera 35 for photographing having sensitivity in the visible range is arranged. In the optical path in the reflection direction of the dichroic mirror 34, an infrared reflection and visible light transmission dichroic mirror 37, a relay lens 36, and an observation CCD camera 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 obliquely disposed between the objective lens 25 and the perforated mirror 22, and further, the dichroic mirror 24 and the perforated mirror 22 are provided. Between them, a parallel plate glass 23 for correcting an optical axis shift by the dichroic mirror 24 is obliquely installed so as to be detachable. 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 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. The parallel plate glass 23 has substantially the same thickness as the dichroic mirror 24 and almost the same refractive index. Further, as shown in FIG. 3, the dichroic mirror 24 and the parallel plate glass 23 are disposed so as to have the same inclination angle θ as a contrast with respect to the optical axis L1 of the fundus oculi observation / photographing optical system. At the time of photographing, the dichroic mirror 24 and the parallel plate glass 23 are flipped up by the insertion / removal mechanism 66 and retracted out of the optical path. The insertion / removal mechanism 66 can be composed of a solenoid and a cam.

  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, and a half mirror 44 obliquely provided in the optical path of the illumination optical system 10. . The light source 41 and the slit index plate 42 are moved in the optical axis direction by the moving mechanism 39 in conjunction with the focusing lens 32.

  The light flux of the slit index plate 42 of the focus index projection optical system 40 is reflected by the half mirror 44 via the deflection prism 43, and then the relay lens 21, the perforated mirror 22, the parallel plate glass 23, the dichroic mirror 24, the objective lens. 25 and projected onto the fundus of the eye E to be examined. When the fundus is out of focus, the index image of the slit index plate 42 is separated and projected in agreement when in focus.

  The alignment index projection optical system 50 includes two sets of first index projection optical systems disposed symmetrically about the optical axis of the objective lens 25, and an optical axis disposed at a narrower angle than the first index projection optical system. And two sets of second index projection optical systems arranged symmetrically with respect to a vertical plane through which the optical axis L1 passes. The two sets of first index projection optical systems each have a light source 51 and a collimating lens 52 that emit infrared light having a center wavelength of 940 nm, and project an infinite target on the eye to be examined by light of a substantially parallel light beam. On the other hand, the two sets of second index projection optical systems have a light source 52 that emits infrared light having a center wavelength of 940 nm, and project a target at a finite distance onto the eye to be examined by a divergent light beam. 2 shows the optical system as viewed from the side, but the alignment index projection optical system 50 is actually arranged in the left-right direction. FIGS. 5A and 5B show the state of the index image formed on the anterior segment image F by the alignment index projection optical system 50. The index images Ma and Mb are the first index projection optical system ( An index image at infinity by the light source 51 and the collimating lens 52), and the index images Mc and Md are index images at a finite distance by the second index projection optical system (light source 53). The second index projection optical system is configured so that the index images Mc and Md are formed below the index images Ma and Mb.

  Further, around the hole of the perforated mirror 22, two infrared light sources 55 (center wavelength: 880 nm) for forming working dots 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. The light source 55 is disposed such that when the working distance between the eye E and the objective lens 25 is appropriate, a distance that is ½ of the radius of curvature of the cornea is a conjugate position.

  The anterior ocular segment observation optical system 60 includes a field lens 61, a mirror 62, a diaphragm 63, a relay lens 64, and a CCD camera 65 having sensitivity in the infrared region on the reflection side of the dichroic mirror 24. The CCD camera 65 also serves as an alignment index detection unit, and the anterior segment illuminated by the anterior segment illumination light source 58 that emits infrared light having a center wavelength of 940 nm is imaged. The alignment index detecting means is advantageously used also for anterior segment imaging, but a dedicated means may be provided.

  The fixation target presenting optical system 70 includes a red light source 74, a target plate 72 having eight fixation targets 71 formed with opening holes, and a relay lens 75. From the dichroic mirror 34 via the dichroic mirror 34. The optical path of the observation optical system 30 up to the objective lens 25 is shared. The fixation target 71 includes a fixation target 71a having an opening hole that leads the vicinity of the posterior pole portion of the right eye to the photographing center, a fixation target 71b having an opening hole that leads the vicinity of the posterior pole portion of the left eye to the photographing center, and a peripheral portion. Is composed of six fixation targets 71c to 71h having an opening hole that guides the line of sight so as to photograph (see FIG. 4). The fixation targets 71 a to 71 h are selectively arranged in front of the light source 74 by the motor 73.

  In the above optical system, the anterior segment illuminated by the anterior segment illumination light source 58 is received by the CCD camera 65 from the objective lens 25, the dichroic mirror 24, and the field lens 61 via the relay lens 64 optical system. 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 passes through the parallel plate glass 23 and the dichroic mirror 24, and once converges near the pupil of the eye E by the objective lens 25, and then diffuses to illuminate the fundus of the eye to be examined. The luminous flux emitted from the imaging illumination light source 14 passes through the condenser lens 15 and then illuminates the fundus of the eye to be examined through the same optical path as the observation illumination luminous flux.

  Reflected light from the fundus illuminated by the observation illumination light is the objective lens 25, the dichroic mirror 24, the parallel plate glass 23, the aperture of the perforated mirror 22, the photographing aperture 31, the focusing lens 32, the imaging lens 33, and the dichroic mirror 34. The image is formed on the CCD camera 38 via the dichroic mirror 37 and the relay lens 36. At this time, as shown in FIG. 3, the optical axis L1 of the fundus oculi observation / photographing optical system becomes an optical axis L1a which is deviated by the insertion of the dichroic mirror 24. The place is returned. For this reason, the imaging of the anterior segment by the CCD camera 65 and the imaging of the fundus by the CCD camera 38 can be performed satisfactorily at the same time.

  Here, when there is no parallel plate glass 23, the displaced optical axis L1a does not pass through the center of the photographing aperture 31. In this case, the center of the ring illumination light reflected by the anterior segment and the center of the photographing aperture 31 are shifted, and even when the alignment is completed, the CCD camera 38 for fundus observation reflects from the anterior segment. Light enters. For this reason, flare light tends to occur in the observation elephant, a good fundus observation image cannot be obtained, and the focus index cannot be detected accurately.

  At the time of photographing, the dichroic mirror 24 and the parallel plate glass 23 are retracted out of the optical path by the insertion / removal mechanism 66, and the reflected light from the fundus illuminated by the photographing illumination light includes the objective lens 25, the perforated mirror 22, the photographing aperture 31, An image is formed on a CCD camera 35 for photographing through a focusing lens 32 and a dichroic mirror 34. The CCD camera 35 can also be used as an observation camera.

  The outputs of the CCD cameras 65, 38, and 35 are connected to the image processing unit 80. The image processing unit 80 detects the alignment index and the pupil region from the anterior segment image captured by the CCD camera 65 and detects the focus index from the fundus image captured by the CCD camera 38. The image processing unit 80 is connected to the monitor 8 and controls the display image. The control unit 81 includes an image processing unit 80, a Y driving unit 6, an XZ driving unit 7, a joystick 4, a solenoid 26, a moving mechanism 39, an insertion / removal mechanism 66, a motor 73, a photographing switch 83, and a switch unit having various operation switches. 84, each light source etc. is connected.

  The operation of the apparatus having the above configuration will be described. At the time of alignment, the dichroic mirror 24 and the parallel plate glass 23 are inserted into the optical path of the fundus oculi observation / imaging optical system 30. The anterior segment illuminated by the anterior segment illumination light source 58 is received by the CCD camera 65 from the objective lens 25, the dichroic mirror 24 and the field lens 61 via the optical system of the relay lens 64. An anterior segment image captured on the screen is displayed. The examiner observes the anterior segment image displayed on the monitor 8, and adjusts the imaging unit 3 roughly with respect to the subject's eye by operating the joystick 4. When the anterior segment image appears on the monitor 8, four index images Ma, Mb, Mc, and Md also appear as shown in FIG. In FIG. 5, Na, Nb, Nc, and Nd are line-shaped reticle marks, and Ne is a ring mark that indicates a pupil diameter necessary for imaging. These are electrically formed by the image processing unit 80. It is a thing. As shown in FIG. 5B, the photographing unit 3 is moved left and right and up and down so that the index images Ma, Mb, Mc, and Md are positioned on the reticle marks Na, Nb, Nc, and Nd. In the front-rear direction (working distance direction), the photographing unit 3 is moved so that the index image is focused.

  When the four index images Ma to Md picked up by the CCD camera 65 are detected by the image processing unit 80, the control unit 81 obtains a deviation amount (positional deviation) with respect to the alignment reference based on these index images. . The control unit 81 obtains the deviation amount Δd with respect to the alignment reference position O in the XY directions, with the intermediate position between the index images Ma and Mb as the corneal apex position Mo. Then, the automatic alignment by the drive control of the XZ drive unit 7 and the Y drive unit 6 is operated so that the deviation amount Δd falls within the allowable range for completion of alignment.

  Further, the alignment state in the Z direction is detected by comparing the interval between the index images Ma and Mb and the interval between the index images Mc and Md. This is because when the corneal reflection image is formed by an infinite light source and a finite light source, the image height of the corneal reflection image by the infinite light source does not change even if the working distance changes, but the image height by the finite light source does not change. This utilizes the characteristic that it changes as the working distance changes (refer to Japanese Patent Laid-Open No. 6-46999 for details). In the Z direction, based on the same idea as the XY direction, the amount of deviation with respect to the alignment reference position in the Z direction is obtained, and automatic alignment by drive control of the XZ drive unit 7 is performed so that the amount of deviation falls within the allowable range of alignment completion. Operate.

  When the alignment state in the XYZ directions satisfies the alignment completion condition, the control unit 81 stops the automatic alignment operation. At this time, the size and line-of-sight direction of the pupil region is detected from the anterior segment image captured by the CCD camera 65, and switching of the ring slits 17a and 17b is controlled based on the size information of the pupil region. Further, the size of the mask for electronically limiting the display area of the fundus image displayed on the monitor 8 is controlled based on the switching of the ring slits 17a and 17b and the information on the line of sight.

  FIG. 6 is an example of an anterior segment image captured by the CCD camera 65 when the alignment of the right eye is completed. First, switching of the ring slits 17a and 17b is determined based on whether or not the pupil edge (that is, the pupil region) Pu detected from the anterior eye image F is outside the determination area T2. For the pupil edge Pu, four pupil edges detected in the horizontal direction and the vertical direction with reference to the center of the image that is the imaging optical axis may be used. The determination area T2 is set, for example, as a diameter of 4 mm around the center of the optical axis. If the pupil edge Pu is outside the determination area T2, it is determined that the large ring slit 17a is used because the ring illumination light beam sufficiently enters the eye through the pupil even in the large ring slit 17a. On the other hand, when the pupil edge Pu is inside the determination area T2, if the large ring slit 17a remains, the center of the fundus image becomes dark. This occurs because the illumination light component is not illuminated on the fundus near an angle of view of 0 °. Therefore, in this case, it is determined that the small ring slit 17b is used.

  The ring slits 17a and 17b are switched automatically by detecting the pupil region as described above, and by the switches 84a and 84b for switching the ring slits 17a and 17b according to the size of the pupil diameter. The ring slits 17a and 17b can be switched.

  With regard to the line-of-sight direction, whether the distance R between the pupil center P1 detected from the anterior segment image F and the corneal apex position Mo, which is an intermediate position between the index images Ma and Mb, exceeds the line-of-sight determination distance T1, It is determined whether the image is taken around the area or the surrounding area. The line-of-sight determination distance T1 is a value indicating the boundary between the direction of the subject's line-of-sight and the imaging optical axis direction or the peripheral direction, and is stored in the memory 85 in advance. The pupil center P1 is obtained, for example, as the barycentric position of the pupil edge. In a simple manner, the pupil edge can be detected in the horizontal direction and the vertical direction with reference to the center of the image, and can be obtained as the detected barycentric positions. If the distance R between the pupil center P1 and the corneal apex position Mo does not exceed the line-of-sight determination distance T1, it is determined that the line-of-sight direction is guided to the imaging optical axis and the imaging is performed around the rear pole. The That is, the fixation target 71a is presented. On the other hand, when the distance R between the pupil center P1 and the corneal apex position Mo exceeds the line-of-sight determination distance T1, it is determined that the peripheral portion is captured. In this case, one of the fixation targets 71c to 71h is presented for peripheral photographing.

  The size of the image mask that electronically restricts the display area of the fundus image displayed on the monitor 8 is controlled as shown in FIG. 7 based on the determination of switching the ring slits 17a and 17b and the detection of the line of sight. . In the case of imaging centered around the rear pole (when the distance between the pupil center P1 and the corneal apex position Mo does not exceed the line-of-sight determination distance T1) and the large ring slit 17a is used, FIG. As shown in a), the mask size is a large mask 90a corresponding to an angle of view of 45 °. In the case of photographing centering on the vicinity of the rear pole and using the small ring slit 17b, the mask size is set to a small mask 90b corresponding to an angle of view of 37 ° as shown in FIG. 7B.

  The size of the image mask in the case of peripheral photographing (when the distance R between the pupil center P1 and the corneal apex position Mo exceeds the line-of-sight determination distance T1) will be described. In normal photographing around the rear pole portion, the axis L1 of the photographing optical system coincides with the axis of the eye as shown in FIG. 8A, but in the case of peripheral photographing, FIG. The eyeball tilts like this, and the imaging performance of the ring slit is inferior compared to the imaging at the center of the rear pole. For this reason, compared with photographing at the center of the rear pole part, flare due to the reflected light of the crystalline lens is likely to occur in the outer peripheral part of fundus photographing. As a countermeasure for this, in the case of peripheral photographing, the ring slits 17a and 17b are switched according to the size of the pupil region, and the size of the image mask is further reduced with respect to photographing around the rear pole portion. That is, in the case of peripheral photographing and when the large ring slit 17a is used, as shown in FIG. 7C, the mask size is set to the middle mask 90c corresponding to an angle of view 42 ° slightly smaller than the large mask 90a. . In the case of peripheral photographing and when the small ring slit 17b is used, the mask size is set to a mask 90d corresponding to an angle of view 34 ° smaller than that of the small mask 90a as shown in FIG. FIGS. 7C and 7D show examples in which the fixation target 71 for peripheral photographing is selected so that the nipple is located on the left side.

  In the above description, the image processing unit 80 determines whether the peripheral photographing or the center of the vicinity of the posterior pole is detected based on the anterior ocular segment image. Of course, the fixation is an input signal of the fixation target presenting position. The selection signals of the marks 71a to 71h may be used as they are.

  In the above description, when alignment completion is detected, switching of the ring slit and the mask size is determined by comparing the pupil area imaged by the CCD camera 65 with the determination area T2. However, the present invention is not limited to this. By binarizing by the image processing unit 80, the pupil diameter is measured from the binarized image, and compared with the threshold of the pupil diameter stored in the memory or the like, thereby determining the size of the pupil diameter, The mask size may be changed.

  The operation after the alignment is completed will be described. When the alignment is completed by the movement of the photographing unit 3, the display image on the monitor 8 is automatically switched from the anterior ocular segment image to the fundus oculi image. At this time, as described above, the illumination optical system 10 is provided with the ring slit 17a or 17b based on the detection information of the size of the pupil region, and the switching determination of the ring slits 17a and 17b and the detection of the gaze direction The mask size of the fundus observation image displayed on the monitor 8 is changed to any one of FIGS. 7A to 7D based on (input information on the fixation target presenting position). Further, autofocus is executed based on detection of a focus index image picked up by the CCD camera 38.

  FIG. 9 is an example of a fundus image captured by the CCD camera 38, and focus index images S 1 and S 2 by the focus target projection optical system 40 are projected on the center of the fundus image R. The focus index images S1 and S2 are separated when they are not in focus, and are projected in agreement when they are in focus. The focus index images S <b> 1 and S <b> 2 are detected and processed by the image processing unit 80, and the separation information is sent to the control unit 81. Based on the separation information of the focus index images S1 and S2, the control unit 81 controls the movement of the moving mechanism 39 so that the two coincide with each other, thereby focusing the fundus. Focusing can be done manually by the examiner.

  The examiner observes the fundus image displayed on the monitor 8, confirms the presence or absence of flare, etc., and performs fine adjustment of alignment by operating the joystick 4 or the like as necessary. Thereafter, shooting is performed by pressing the shooting switch 83. The controller 81 drives the insertion / removal mechanism 66 to detach the dichroic mirror 24 and the parallel plate glass 23 from the optical path, and emits the photographing light source 14. The fundus is illuminated with visible light by the light emission of the imaging light source 14, and the reflected light from the fundus occupies the objective lens 25, the aperture of the perforated mirror 22, the imaging aperture 31, the focusing lens 32, the imaging lens 33, and the dichroic mirror 34. Then, an image is formed on the CCD camera 35. The display on the monitor 8 is switched to a color fundus image captured by the CCD camera 35 by the image processing unit 80. Also in the fundus image displayed at this time, the mask size is changed to any one of FIGS. The fundus image captured by the CCD camera 35 is stored in the memory 85 together with mask size data. When outputting fundus image data to the outside, it is sent together with mask size data. For this reason, when displaying on another monitor, it is possible to obtain a fundus image in a state where the mask is electronically masked using the mask size data in the same manner as the monitor 8. The fundus image itself stored in the memory 85 may be trimmed based on the mask size data.

It is a block diagram of a non-mydriatic type fundus camera according to the present invention. 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 correction | amendment of the optical axis offset produced by an optical path branching member, and the optical axis offset by a parallel plate glass. It is a figure explaining the composition of a fixation target. It is a figure which shows the anterior ocular segment image imaged with the CCD camera for anterior ocular segment observation. It is a figure explaining determination of a look direction and a pupil diameter. It is a figure explaining the size of the image mask which restrict | limits the display area of a fundus image. It is a figure explaining the relationship between the axis | shaft of an imaging optical system, and the axis | shaft of an eye. It is a figure which shows the fundus image displayed on the monitor.

Explanation of symbols

8 monitor 10 illumination optical system 17a large ring slit 17b small ring slit 26 solenoid 35 CCD camera 38 CCD camera 71 fixation target 71a-h fixation target 72 target plate 73 motor 80 image processing unit 81 control unit

Claims (2)

An alignment index projection optical system for projecting an alignment index toward the cornea of the eye to be examined, an illumination optical system for illuminating the fundus of the eye to be examined, and an imaging optical system for photographing the fundus illuminated by the illumination optical system with an imaging device And a display means for displaying a fundus image photographed by the photographing element, in a fundus camera for photographing the fundus of the eye to be examined by aligning with the eye to be examined using a cornea reflection image, on the pupil of the eye to be examined A determination means for determining whether or not a pupil edge of the eye to be inspected is set in the determination range by setting a predetermined determination range centering on the imaging optical axis located at a position substantially conjugate with the pupil of the eye to be inspected change of the inner diameter changing means for changing on the basis of the inner diameter of the ring slit provided in the illumination optical system on a determination result of said determining means for generating an illumination light beam of the ring, by the inner diameter changing means It said ring fundus camera based on the inner diameter information of the slit, characterized in that it comprises, a mask changing means for changing the mask size of electronically limit the display area of the fundus image displayed on the display means is. In a fundus camera comprising an illumination optical system that illuminates the fundus of the subject's eye and an imaging optical system that captures an image of the fundus illuminated by the illumination optical system, display means for displaying a fundus image captured by the imaging element An inner diameter variable ring slit provided in the illumination optical system for forming a ring-shaped illumination light beam at a position substantially conjugate with the pupil of the eye to be examined, inner diameter variable means for changing the inner diameter of the ring slit, Fixation target presenting means capable of changing the position of the fixation target that guides the eye-gaze direction of the optometry, and is fixed to a reference position for photographing around the posterior pole of the fundus and a peripheral position for photographing the periphery of the fundus. Fixation target presenting means capable of changing the presentation position of the visual target, and a fixation target in which the visual line direction of the subject eye is detected or the visual line direction of the subject eye is induced by the fixation target presentation of the fixation target presentation unit Enter presentation position information A display area of the fundus image displayed on the display means based on the inner diameter information of the slit by the gaze detection / input means and the detection result or the input result by the gaze detection / input means. A fundus camera comprising: a mask changing unit that changes a mask size to be restricted .