JP2009240625A - Fundus camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To photograph using a simple configuration and taking astigmatic components of an eye to be photographed into consideration. <P>SOLUTION: A fundus camera icnludes a driving mechanism which moves a focusing lens in a direction of the optical axis; a fundus photographing optical system for photographing the fundus by an image pickup device; a measurement data obtaining unit to obtain measurement data including astigmatic power of the eye measured by an auto ref keratometer; a focus detection unit to receive luminous flux irradiating the fundus and to detect a focusing state of the fundus; and a control unit to display the focusing state obtained from results detected by the focus detection unit as first focusing information. When the focusing lens is driven using the obtained measurement data, the control unit is arranged to set a focusing completion position of the focusing lens at a position corresponding to spherical equivalent power of the eye, and changes displays of focusing information based on the set position as second focusing information which is different from the first focusing information. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fundus imaging apparatus that images the fundus of a subject's eye.

  Conventionally, a fundus photographing apparatus that photographs the fundus of the eye to be examined has been provided with a focusing lens for focusing on the fundus of the eye to be examined, and the focusing lens is moved in the optical axis direction manually or automatically (autofocus). As a result, the fundus of the eye to be examined and the image sensor are focused.

  In addition, as a configuration for notifying the examiner of the focus state with the fundus of the eye to be examined, a split index is projected onto the fundus of the eye to be examined, the reflected light is received by the image pickup device of the fundus observation optical system, and the image pickup signal is displayed on the monitor In general, a technique for notifying the examiner of the focus state from the split state of the split index when it is output to the subject (see Patent Document 1).

As another configuration, the focusing light beam is projected onto the fundus of the eye to be examined, the reflected light is received by the light receiving element, and the focus state with respect to the eye fundus of the eye to be examined is displayed on the display monitor based on the light reception signal from the light receiving element. An electronic display is known (see Patent Document 2). Patent Document 2 discloses a configuration for correcting astigmatism of an eye to be examined by an optical system that measures the refractive index of the eye to be examined in the two meridian directions and a cross cylinder.
JP 2007-202724 A Japanese Patent Laid-Open No. 9-66031

  By the way, in recent years, the fundus image of the subject's eye is often imaged by a two-dimensional image sensor with high pixels, and the acquired fundus image is often displayed on a large screen such as a personal computer display for observation. In such a case, for example, if a fundus image of an intense astigmatic eye is displayed, the fundus image that is not particularly noticeable on a small monitor screen may become noticeable and may be difficult to observe. Therefore, it is desired to correct a refractive error including an astigmatism component of the eye to be examined. However, in the apparatus of Patent Document 2, in order to correct astigmatism of the eye to be examined, a complicated focus detection system and a correction optical system are required, and the optical arrangement becomes complicated.

  In view of the above problems, an object of the present invention is to provide a fundus imaging apparatus that can perform imaging taking into account astigmatism components of an eye to be examined with a simple configuration.

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

(1) a fundus photographing optical system having a driving mechanism for moving the focusing lens in the optical axis direction and photographing the fundus of the eye to be examined by an image sensor;
Eye refractive power measurement data acquisition means for acquiring measurement data including the astigmatism power of the subject's eye measured by an eye refractive power measurement device in a separate housing;
A focus detection means for detecting a focus state with respect to the subject's eye fundus by receiving a focusing light beam irradiated to the subject's eye fundus;
Control means for displaying the focus state obtained based on the detection result from the focus detection means on the monitor as the first focus information,
When driving the focusing lens using the measurement data acquired by the data acquisition means, the control means sets the focus completion position of the focusing lens to a position corresponding to the equivalent spherical power of the eye to be examined, and the setting The focus information based on the position is switched and displayed on the monitor as second focus information different from the first focus information.
(2) The fundus imaging apparatus according to (1) includes second focus detection means for detecting a focus state with respect to the fundus of the eye to be examined based on a moving position of the focusing lens corresponding to the equivalent spherical power of the eye to be examined, and the data acquisition means When the focusing lens is driven using the measurement data acquired by the control unit, the control unit determines a focus shift amount and a shift direction with respect to the fundus of the eye to be inspected based on a detection result from the second focus detection unit. The second focus information is displayed on the monitor.
(3) In the fundus imaging apparatus according to (2), the fundus photographing apparatus includes: an autofocus unit that automatically moves the focusing lens by controlling driving of the drive mechanism based on a detection result from the focus detection unit; When the focusing lens is driven by the operation of the means, the control means displays the first focus information on a monitor.
(4) The control means in (3) displays two focus bars on the monitor as the first and second focus information, and drives the focusing lens by operating the autofocus means. While changing the separation direction and the separation amount of the two focus bars optically or electronically displayed on the monitor based on the detection result from the focus detection means, the measurement data acquired by the data acquisition means is changed. When the focusing lens is used to drive, the separation direction and the separation amount of the two focus bars electronically displayed on the monitor are changed based on the detection result from the second focus detection means. And
(5) The control means of (4) electronically displays two focus bars on the monitor as the first and second focus information, and drives the focusing lens by the operation of the autofocus means. The display mode of the two focus bars is switched between when the focusing lens is driven using the measurement data acquired by the data acquisition means.
(6) The control means of (5) is when the focusing lens is driven by the operation of the autofocus means and when the focusing lens is driven using the measurement data acquired by the data acquisition means. In addition, at least one of the color, display position, separation direction, and shape of the two focus bars electronically displayed on the monitor is changed.
(7) In the fundus imaging apparatus according to (6),
A first focus mode for setting a moving position of the focusing lens by the operation of the autofocus means as a focus completion position, and the focusing when the drive mechanism is driven and controlled based on the measurement data acquired by the data acquisition means It is characterized by comprising mode switching means for generating a mode switching signal for selectively switching between the second focus mode in which the lens movement position is set as the focus completion position.
(8) In the fundus imaging apparatus according to (7), the fundus imaging apparatus includes determination means for determining whether or not the astigmatism power of the eye to be examined in the measurement data acquired by the eye refractive power measurement data acquisition means is within a predetermined range,
When the determination means determines that the astigmatism power of the eye to be examined is within a predetermined range, the control means selects the first focus mode by the mode switching means, and the determination means determines the astigmatism power of the eye to be examined. Is determined to be outside the predetermined range, the mode switching means selects the second focus mode.

  According to the present invention, it is possible to perform imaging taking into account the astigmatism component of the eye to be examined with a simple configuration.

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

  The fundus camera includes a base 1, a movable base 2 that can move in the left and right direction (X direction) and the front and rear (working distance) direction (Z direction) with respect to the base 1, and a three-dimensional direction with respect to the movable base 2. And a face support unit 5 fixed to the base 1 in order to support the face of the subject. The imaging unit 3 is moved in the left-right direction, the up-down direction (Y direction), and the front-rear direction with respect to the 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 presenting 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. An aperture mirror (hole mirror) 22 and an objective lens 25 disposed in front of the eye to be examined are included. 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. . Here, the perforated mirror 22 is disposed at a position substantially conjugate with the eye pupil to be examined with respect to the objective lens 25, and the imaging aperture 31 is disposed at a position substantially conjugate with the cornea 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 (first driving 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 diopter correction lens 32a (at least one of a plus lens and a minus lens) that can be inserted into and removed from the photographing optical path of the photographing optical system 30 is provided between the focusing lens 32 and the photographing diaphragm 31. A drive mechanism 89 that has a motor and inserts and removes the diopter correction lens 32a is inserted into the optical path when the eye to be examined has a strong refractive error.

  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 passed through the objective lens 25, the aperture of the perforated mirror 22, the photographing aperture 31, the focusing lens 32, and the imaging lens 33. The image is formed on the two-dimensional image sensor 35.

    <Focus Index Projection Optical System> Further, as a focus detection optical system for detecting a focus state with respect to the eye fundus of the subject by receiving the focus beam irradiated on the eye fundus of the subject, the focus light beam is applied to the eye fundus of the eye to be examined. An irradiation optical system (projection optical system) for irradiating (projecting) and a light receiving optical system for receiving a focusing light beam irradiated to the fundus of the eye to be examined by a light receiving element are provided.

  More specifically, the focus index projection optical system 40 as an irradiation optical system 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. A spot mirror 44 is provided obliquely in the optical path of the optical system 10. 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 deflection 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 on the fundus of the eye E are imaged together with the fundus image by the imaging device 38 for fundus observation and displayed on the monitor 8 (see FIG. 4). In this case, the fundus oculi observation optical system 30 is used as a light receiving optical system that receives a fundus reflected light beam by a focusing light beam projected onto the fundus of the subject's eye by a light receiving element.

  <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.

  Further, around the hole of the perforated mirror 22, two infrared light sources 55 (center wavelength 880 nm) for forming an optical alignment index (working dot W1) on the cornea of the eye to be examined are centered on the optical axis L1. Arranged symmetrically. 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> The fixation target presenting optical system 70 for guiding the line of sight of the eye to be examined includes a red light source 74, a light shielding plate 71 having an opening hole, and a relay lens 75, and a dichroic mirror 37. The optical path of the observation optical system 30 from the flip-up mirror 34 to the objective lens 25 is shared.

  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 the opening hole of the light shielding plate 71 as a fixation target.

  <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 a moving mechanism 49, an insertion / removal mechanism 39, an insertion / removal mechanism 66, a drive mechanism 89, a rotary knob 4a provided on the joystick 4, a photographing switch 4b for generating a photographing start trigger, and various switches. Are connected to a switch unit 84, a memory 85 as a storage means, a connector 86, each light source, and the like. Further, the control unit 80 detects the focus state with respect to the fundus of the eye to be examined based on the detection position of the focus index received by the image sensor 38, and controls the driving of the moving mechanism 49 based on the detection result to focus the lens 32. Autofocus control that automatically moves the camera. Further, in this apparatus, the moving mechanism 49 is driven based on the first focus mode in which the moving position of the focusing lens 32 by the operation of the autofocus control is set as the focus completion position and the measurement data acquired from the eye refractive power measurement apparatus. The second focus mode in which the moving position of the focusing lens 32 when controlled is set as the focus completion position can be selectively switched. The switch unit 84 includes a focus adjustment switch 84a for performing focus adjustment of the fundus image, a changeover switch 84b for switching the observation image displayed on the monitor 8 between the anterior eye image and the fundus image, and the diopter correction lens 32a. A diopter correction switch 84c for inserting / removing the lens, a mode switch 84d for switching between the first focus mode and the second focus mode, and the like are disposed. The memory 85 stores a control program for the control unit 80 to perform various controls.

  The control unit 80 is connected to a left / right eye discriminating unit 110 for discriminating whether or not the eye to be inspected by the imaging unit 3 is either the left eye or the right eye. The left and right eyes of the subject are discriminated based on the output signal output from the eye discriminating unit 110. For example, the left and right eye discriminating unit 110 discriminates the left and right eyes by detecting whether the imaging unit 3 is positioned on the left or right with respect to the center of the left and right by a position detection sensor such as a micro switch or a potentiometer. Configuration is conceivable.

  The operation of the apparatus having the above configuration will be described below. Next, the examiner supports the subject's face by the face support unit 5. In the initial stage, the dichroic mirror 24 is inserted in the optical path of the fundus oculi observation / imaging optical system 30, and the anterior segment image captured by the image sensor 65 is displayed on the monitor 8. The examiner observes the anterior ocular segment image displayed on the monitor 8 and adjusts the joystick 4 so that the anterior ocular segment image of the subject's eye to be imaged (for example, the right eye) is positioned at the display center of the monitor 8. As a result of the above operation, the apparatus main body incorporating the above-mentioned optical system is moved up and down and up and down. Further, the apparatus main body is moved back and forth so that the anterior segment image is in focus.

  Here, when the imaging unit 3 is placed to the left of the center of the apparatus as viewed from the examiner, the control unit 80 captures an image by the imaging unit 3 based on a signal from the left and right eye determination unit 110. The eye to be examined (photographed eye) is determined to be the right eye, and the determination result is displayed on the monitor 8. In addition, when the imaging unit 3 is placed on the right side of the center of the apparatus as viewed from the examiner, the control unit 80 causes the subject to be imaged by the imaging unit 3 based on a signal from the left and right eye discrimination unit 110. It is determined that the optometry (photographed eye) is the left eye, and the determination result is displayed on the monitor 8.

  In addition, the examiner selects the focus mode using the mode switch 84d. Hereinafter, a case where the first focus mode is set will be described.

  Here, when the alignment with respect to the eye to be examined is completed and the changeover switch 84b is operated, the display screen of the monitor 8 is switched to the fundus image captured by the image sensor 38 (see FIG. 4). FIG. 4 shows an example of a screen when the fundus image of the image sensor 38 is switched by the operation of the changeover switch 84b. When the alignment state is made appropriate to some extent, the fundus image shows the corneal reflection formed by the light source 55. Two working dots W appear. While examining the fundus image, the examiner confirms the focus of the working dot W, the flare of the fundus image, and the like, and further finely adjusts the alignment state by manual operation of the joystick so that photographing can be performed in a desired state.

  Here, the control unit 80 issues a switching signal to the first focus mode based on the operation signal from the mode switching switch 84d, and the focus on the fundus obtained based on the detection result from the focus detection optical system. The state is displayed on the monitor 8 as the first focus information. More specifically, when the alignment with respect to the eye to be examined is performed, the focus indicators S1 and S2 are detected on the image sensor 38, and the focus indicators S1 and S2 are also displayed on the display screen on the monitor 8. That is, the control unit 80 displays the first focus information on the fundus of the eye to be examined on the display monitor 8 by displaying the imaging signal output from the imaging element 38 on the display monitor 8. In this case, the index images S1 and S2 are displayed separately when the fundus is out of focus, and are displayed in agreement when the fundus is in focus.

  Further, when the focus index S1 or S2 is detected on the image sensor 38 as described above, the controller 80 controls the driving of the moving mechanism 49 based on the light reception signal from the image sensor 38, Start autofocus on the fundus of the eye to be examined. In this case, the focus index images S1 and S2 acquired by the image sensor 38 are detected by the control unit 80, and the separation information is acquired. The control unit 80 detects the focus state between the eye to be examined and the imaging device 35 (imaging device 38) based on the separation information of the focus index images S1 and S2, and drives and controls the moving mechanism 49 so that the two coincide with each other. Automatically adjust the fundus focus. And the control part 80 will stop the action | operation of the moving mechanism 49, if the position of focus parameter | index S1 * S2 corresponds. Thereby, the focusing lens 32 is arranged at the moving position of the focusing lens 32 by the autofocus control set as the focus completion position in the first focus mode. In this case, the control unit 80 displays on the monitor 8 that autofocus has been performed.

  Note that after the autofocus control is executed as described above, the examiner observes the observation desired by the examiner while confirming the deviation amount and the deviation direction of the focus indicators S1 and S2 optically displayed on the monitor 8. You may make it focus on a site | part (for example, nipple site | part).

  The focus indices S1 and S2 displayed on the monitor 8 are projected onto the fundus of the eye to be examined through the meridian direction in the vertical direction of the eye pupil area to be examined. Therefore, the state in which the above-described focus indicators S1 and S2 match indicates that the eye is in focus in the vertical direction (90-degree direction), and the state in which the focus indicators S1 and S2 are separated is as follows: This means that the focus in the vertical direction (90-degree direction) of the eye to be examined is shifted. Therefore, when the eye to be examined has astigmatism, even if the focus indices S1 and S2 are in agreement, the refractive error is not corrected in other meridian directions. There is a possibility that the fundus image picked up by the image pickup device 35 is totally blurred. When the subject's eye does not have astigmatism or when the astigmatism power is small, it can be considered that the refractive error of the subject's eye is almost corrected and the focus adjustment on the fundus of the subject's eye is properly performed.

  Next, a case where the second focus mode is set using the mode changeover switch 84d will be described. Here, the control unit 80 issues a switching signal to the second focus mode based on the operation signal from the above-described mode switching switch 84d, and drives the focusing lens 32 using the measurement data acquired by the auto reflex. In this case, the control unit 80 sets the focus completion position of the focusing lens 32 to a position corresponding to the equivalent spherical power of the eye to be examined, and sets the focus information based on the set position to the second focus information different from the first focus information. Is switched and displayed on the monitor 8.

  More specifically, when performing the second focus mode, it is necessary to obtain measurement data from the eye refractive power measurement device in advance. That is, the examiner inputs an ID number previously assigned to each subject using a predetermined switch provided in the switch unit 84. The control unit 80 acquires measurement data corresponding to the input ID number from the memory 85 from among a plurality of measurement data stored in the memory 85. In addition, when there is no data corresponding to the input ID number among the plurality of measurement data stored in the memory 85, the control unit 80 displays on the monitor 8 to that effect. Then, when there is no eye refractive power measurement data of the eye to be examined, the control unit 80 keeps the focusing lens 32 in an initial state (a state of S = 0). However, if the examiner can know the measurement data of the eye to be examined, the measurement data may be input using a numeric keypad provided on the switch unit 84 or the like.

  Then, the control unit 80 moves the focusing lens 32 based on the measurement data corresponding to the left / right eye discrimination result based on the discrimination result discriminated by the left / right eye discrimination unit 110. In this case, the control unit 80 controls the driving of the moving mechanism 49 to place the focusing lens 32 at a position corresponding to the equivalent spherical power of the eye to be calculated that is calculated based on the spherical power and astigmatism power of the eye to be measured in the measurement data. The astigmatism state of the eye to be examined is corrected by automatically moving it.

  Here, when the left eye discriminating unit 110 determines that the eye to be examined is the right eye, the control unit 80 determines the eye to be examined based on the spherical power and astigmatism power of the eye to be examined (right eye) included in the measurement data of the right eye. The equivalent spherical power (SE: SE = S + 1 / 2C) is calculated. Then, the control unit 80 acquires a drive signal (for example, a movement amount from the reference position (position corresponding to 0D)) of the moving mechanism 49 corresponding to the calculated equivalent spherical power from the memory 85, and the acquired driving Based on the signal, the moving mechanism 49 is driven and controlled so that the focusing lens 32 is moved to a position corresponding to the equivalent spherical power. By such astigmatism correction control, the focusing lens 32 is moved to a position corresponding to (corresponding to) the equivalent spherical power of the eye to be examined, and astigmatism of the eye to be examined is corrected. Note that each drive signal (drive information) of the moving mechanism 49 corresponding to the equivalent spherical power of the eye to be examined is calculated in advance by calculation or the like and stored in the memory 85. In this case, the correspondence between the moving position of the focusing lens 32 and the eye refractive power value of the eye to be examined may be obtained in advance. In the above control, the focusing lens 32 may be moved based on the equivalent spherical power calculated on the auto reflex side. As a result, the focusing lens 32 is positioned at an intermediate position between the refractive abnormality in the strong main meridian direction and the refractive abnormality in the weak main meridian direction of the eye to be examined. Therefore, the refractive abnormality in each meridian direction of the eye to be examined is detected. Can be suppressed overall.

  Further, the control unit 80 drives the driving mechanism 89 when the eye to be inspected is a refractive anomaly eye that exceeds a predetermined value, and the corresponding diopter correction lens 32a (in the case of intensity myopia,-lens, intensity). In the case of hyperopia, the + lens) is inserted into the imaging optical path of the imaging optical system 30.

As described above, when the diopter correction of the eye to be examined and the alignment with respect to the eye to be examined are completed and the changeover switch 84b is operated, the display screen of the monitor 8 is switched to the fundus image captured by the image sensor 38 (FIG. 5).
FIG. 5 is a diagram when the second focus information is displayed together with the fundus observation image, and FIG. 6 is a diagram illustrating the second focus information in an enlarged manner. As described above, when the focusing lens 32 is moved to a position corresponding to the equivalent spherical power of the eye to be examined, the control unit 80 is based on the movement position of the focusing lens 32 corresponding to the equivalent spherical power of the eye to be examined. The focus state with respect to, and the focus shift amount and shift direction with respect to the fundus of the eye to be examined obtained based on the detection result are displayed as second focus information. Further, when displaying the above-described second focus information, the control unit 80 hides the above-described first focus information.

  In FIG. 6A, the indicator is increased or decreased in either plus or minus directions based on the equivalent spherical power SE according to the amount of movement of the focusing lens 32 from the position corresponding to the equivalent spherical power. It has become. Further, in FIG. 6B, the position of the focusing lens 32 is replaced with the refractive power of the eye to be examined, and the equivalent spherical power of the eye to be examined is indicated in the gauge display in which the eye refractive power value is described. The amount of movement of the focusing lens 32 from the movement position corresponding to the equivalent spherical power is displayed.

  When the second focus information is displayed, the control unit 80 detects, for example, the movement amount or movement position of the focusing lens 32 and uses the movement position of the focusing lens 32 corresponding to the equivalent spherical power of the eye to be examined as a reference. The amount of movement of the focusing lens 32 is displayed as second focus information. In this case, as a detection mechanism for detecting the movement amount or movement position of the focusing lens 32, a pulse motor is used as the drive motor of the movement mechanism 49, and a pulse is generated based on the origin position set by the origin position detection unit such as a photosensor. The amount of movement of the focusing lens 32 from the position corresponding to the equivalent spherical power of the eye to be examined is detected by measuring the number of pulses supplied to the motor, and this may be displayed as the second focus information.

  Further, the present invention is not limited to the above configuration, and the separation state of the focus indicators S1 and S2 received by the image sensor 38 in a state where the focusing lens 32 is moved to a position corresponding to the equivalent spherical power of the eye to be examined is used as a reference. The movement position of the focusing lens 32 corresponding to the equivalent spherical power of the eye to be examined by detecting the movement direction and the movement amount (for example, the movement amount of the focus index) of the focus indicators S1 and S2 from the reference separation state by image processing. The focus state with respect to the fundus of the eye to be examined may be detected based on the above, and this may be displayed as the second focus information.

  Further, when the first focus information is not displayed, the control unit 80 performs a blacking process on the display positions of the focus indicators S1 and S2, or causes the rotary solenoid 46 to retract the lever 45 from the illumination optical path. Can be considered.

  Here, the examiner checks the focus shift amount and the shift direction from the focus position corresponding to the equivalent spherical power of the eye to be examined by using a focus index (see FIG. 6) electronically displayed on the monitor 8. It is possible to focus on the observation site desired by the person (for example, the nipple site).

  In this way, the examiner can perform focus adjustment on the fundus of the eye to be examined with reference to the focus position corresponding to the equivalent spherical power of the eye to be examined set for correcting astigmatism of the eye to be examined. In addition, when the focusing lens 32 is moved to a position corresponding to the equivalent spherical power of the eye to be examined, when the focus indicators S1 and S2 received by the image sensor 38 are displayed on the monitor 8, the focus indicators S1 and S2 are shifted. However, by displaying the second focus information based on the focus position corresponding to the equivalent spherical power of the eye to be examined as described above, the examiner unexpectedly adjusts the focus. Therefore, it can be avoided that the focus on the fundus of the subject's eye is shifted.

  As described above, after the focus adjustment on the eye to be examined is completed in either the first focus mode or the second focus mode, photographing is performed by the examiner pressing the photographing switch 4b. When the trigger signal of the photographing switch 4b is input, the control unit 80 drives the insertion / removal mechanism 66 to remove the dichroic mirror 24 from the optical path and drives the insertion / removal mechanism 39 to remove the flip-up mirror from the optical path. The photographing light source 14 emits light. The fundus is illuminated with visible light by the light emitted from the imaging light source 14, and the reflected light from the fundus forms an image on the image sensor 35. The display on the monitor 8 is switched to a color fundus image captured by the image sensor 35. The fundus image captured by the image sensor 35 is stored in the memory 85.

  When the fundus imaging of the right eye is completed as described above, the examiner operates the joystick 4 to move the imaging unit 3 in the left eye direction. When the second focus mode is set and the left eye is photographed after the right eye of the subject's eye is photographed, the control unit 80 determines the left and right eyes based on the output signal from the left and right eye discrimination unit 110. The switching is detected, and the moving mechanism 49 is driven and controlled based on the measurement data corresponding to the eye to be newly determined as the photographing eye.

  More specifically, since the imaging unit 3 is moved to the right side with respect to the center of the apparatus as viewed from the examiner, the control unit 80 determines that the imaging eye is left based on the input signal input from the left and right eye determination unit 110. The eye is discriminated and the discrimination result is displayed on the monitor 8. Then, the control unit 80 controls the movement of the moving mechanism 49 based on the measurement data of the left eye acquired from the memory 85 and moves the focusing lens 32 as in the case of the right eye. The following description is performed by the same method as that for right-eye photography, and thus the description thereof is omitted.

  Hereinafter, a case where a mode switching signal for switching between the first focus mode and the second focus mode is automatically issued will be described. Here, the control unit 80 determines whether or not the astigmatism power of the eye to be examined in the measurement data acquired from the auto-ref is within a predetermined range, and it is determined that the astigmatism power of the eye to be examined is within the predetermined range. When the first focus mode is selected, the second focus mode is selected when it is determined that the astigmatism power of the eye to be examined is out of the predetermined range.

  For example, when it is determined that the absolute value of the astigmatism power of the eye to be examined in the measurement data is smaller than 1.0, the control unit 80 issues a permission signal that permits execution of autofocus control in advance. When the focus indicators S1 and S2 are detected on the image sensor 38 in the state where the permission signal is issued, the control unit 80 drives and controls the movement mechanism 49 based on the light reception signal from the image sensor 38, Start autofocus on the fundus of the eye to be examined. And the control part 80 will stop the action | operation of the moving mechanism 49, if the position of focus parameter | index S1 * S2 corresponds. In this case, the control unit 80 displays on the monitor 8 that autofocus has been performed. As described above, autofocus control is performed on an eye to be examined having a small astigmatism power or no astigmatism due to the influence of the condition of the eye to be examined, the measurement error at the auto reflex, the optical arrangement on the fundus camera side, and the like. The position corresponding to the equivalent spherical power of the optometry (spherical power if there is no astigmatism) may not be the proper focus position, and it is more likely that a correct fundus image will be obtained if autofocusing is performed by optical detection. It is.

  On the other hand, when the absolute value of the astigmatism power of the eye to be examined in the measurement data is determined to be 1.0 or more, the focusing lens 32 is driven using the measurement data acquired from the autoref and corresponds to the equivalent spherical power of the eye to be examined. The focusing lens 32 is moved to the position. When the astigmatism power of the eye to be examined is large, even if the refractive error in the predetermined meridian direction is corrected by autofocus, a large refractive error remains in the other meridian direction, and the entire fundus image to be captured is blurred. There is a possibility that. Therefore, it is more likely that a fundus image with less blur is obtained when autofocus is not performed on the eye to be examined.

  As described above, by selecting the driving control of the focusing lens 32 according to the presence / absence of astigmatism of the eye to be examined, it is time-consuming to drive and control the focusing lens by the operation of the autofocus control for the refractive abnormal eye having no astigmatism. Astigmatism can be achieved by controlling the focusing lens based on the spherical power and astigmatism power of the subject's eye measured by the auto-ref for an astigmatism eye with astigmatism. Even an eye can perform astigmatism correction without providing a cylindrical lens mechanism.

  In the initial setting, the second focus mode may be set, and a switching signal from the second focus mode to the first focus mode may be issued only when the astigmatism power of the eye to be examined is within a predetermined range. .

  In the above description, when it is determined that the astigmatism power of the eye to be examined is out of the predetermined range, it corresponds to the equivalent spherical power of the eye to be examined based on the spherical power of the eye to be examined and the astigmatism power obtained from the autoref. Although the focusing lens 32 is moved to a position, the focusing lens 32 can also be moved to a position corresponding to the equivalent spherical power of the eye to be examined based on the astigmatism power and the astigmatic axis angle of the eye to be examined obtained from the auto-ref. It is. In this case, the control unit 80 corrects the refractive error in the vertical direction of the subject eye by autofocus control, and then determines the refractive power in the vertical direction of the subject eye and the astigmatism based on the astigmatic power and the astigmatic axis angle of the subject eye. It is conceivable that the amount of deviation between the intermediate value (1/2 value) of the frequency is obtained and the focusing lens 32 is moved by the amount of deviation. For example, in the case of an eye to be examined (negative reading) with spherical power S = −1.0D (diopter), astigmatism power C = −3.0D, and astigmatic axis angle A = 90 °, the refractive power in the vertical direction of the eye to be examined is − Since it is 1.0D and the intermediate value of the astigmatism power is −2.0D, first, the control unit 80 corrects the refractive error in the vertical direction by autofocus control, and then + 1D minutes from the autofocus end position. The focusing lens 32 is moved (for 1D toward the objective lens 25) to be a focus completion position in the second focus mode.

  In the above description, the second focus information is displayed by increasing or decreasing the indicator, but the present invention is not limited to this. An electronic graphic simulating the two focus bars (focus indicators S1 and S2) displayed as the first focus information in FIG. 4 may be displayed as the second focus information. In this case, for example, as shown in FIG. 7, the control unit 80 is a focus index that is electronically displayed on the monitor 8 in accordance with the amount of movement of the focusing lens 32 from the position corresponding to the equivalent spherical power of the eye to be examined. It is conceivable to change the separation direction and the separation amount of D1 and D2. In this case, when the focusing lens 32 is at a movement position corresponding to the equivalent spherical power of the eye to be examined, the electronic focus indices D1 and D2 are displayed so as to coincide with each other, and from the movement position corresponding to the equivalent spherical power of the eye to be examined. When the focusing lens 32 is moved, the electronic focus indexes D1 and D2 are displayed in a shifted manner according to the moving direction.

  In the above description, the first focus information for the eye fundus to be examined is optically displayed by displaying on the monitor 8 a captured image output from the image sensor 38 that images the focus index projected onto the eye fundus to be examined. However, the present invention is not limited to this, and the first focus information for the eye fundus of the eye to be examined is detected based on the detection result based on the detection result based on the detection result. May be displayed electronically.

  For example, the control unit 80 electronically displays two focus bars on the monitor as the first focus information, and electronically displays on the monitor 8 based on the focus detection result detected from the imaging signal from the image sensor 38. It is conceivable to change the separation direction and the separation amount of the two focus bars displayed on the screen (see FIG. 8). In this case, the control unit 80 uses the separation direction of the focus index images S1 and S2 based on the state where the focus index images S1 and S2 in the captured image acquired based on the light reception signal from the image sensor 38 match. By detecting the separation amount, a focus shift amount and a shift direction with respect to the fundus of the eye to be examined are detected, and a focus state with respect to the fundus of the eye to be examined is electronically displayed. In this case, when the focus index images S1 and S2 in the captured image match, the control unit 80 is displayed so that the electronic focus index images E1 and E2 match, and the focus index image in the captured image is displayed. When S1 and S2 are deviated, the focus index images E1 and E2 are deviated and displayed according to the amount and direction of the deviation.

  Note that two focus bars are optically or electronically displayed as the first focus information, and the first focus detection result (for example, the focus index images S1 and S2 received by the image sensor 38 coincide with each other). The separation direction and the separation amount of the two focus bars are changed based on the state (the focus state with respect to the fundus of the eye to be inspected based on the state), while the two focus bars are electronically displayed as the second focus information. The two focus bars are displayed based on the second focus detection result (for example, the focus state with respect to the fundus of the eye to be detected, which is detected based on the moving position of the focusing lens 32 corresponding to the equivalent spherical power of the eye to be examined). Thus, the examiner can check the focus state and adjust the focus without feeling uncomfortable.

  In this case, two focus bars are electronically displayed on the monitor as the first and second focus information, and the focusing lens 32 is driven by the operation of autofocus control, and the measurement data acquired from the autoref is used. Thus, the difference between the first focus mode and the second focus mode may be easily discriminated by switching the display form of the two focus bars when the focusing lens 32 is driven. More specifically, it may be possible to change at least one of the color, display position, separation direction, and shape of the two focus bars (see FIG. 9).

  In addition, regarding the acquisition of the eye refractive power measurement data of the eye to be examined, in the above description, the measurement data of a plurality of subjects obtained by the auto reflex is stored in the memory 85 of the fundus camera. However, the present invention is not limited to this. However, even when the autoref and the fundus camera are connected via a predetermined server via a network and the measurement data for each subject acquired by the autoref is stored in a database on the server, Applicable. In this case, when the ID number of the subject is input by the examiner, the control unit 80 acquires measurement data corresponding to the input ID number from the server, and based on the acquired measurement data, the focusing lens as described above. 32 moves.

  In the above description, the focusing lens 32 is automatically moved to a predetermined focus completion position by controlling the driving of the moving mechanism 49 based on a predetermined focus signal. The focus information and the second focus information are switched and displayed on the monitor 8 and the focusing lens 32 is moved to a predetermined focus completion position by a manual operation of an examiner who confirms the focus information. Good.

  In the above description, the fundus camera which is one of the fundus photographing apparatuses for photographing the fundus of the subject's eye has been described as an example. However, a scanning laser that obtains a fundus image by scanning the fundus of the subject's eye with laser light. The present invention can also be applied to an optometry apparatus, an optical coherence tomography (OCT) or the like that obtains a tomographic image of the fundus of the eye to be examined by irradiating measurement light onto the fundus of the eye to be examined and causing the reflected light to interfere with reference light.

  A method other than the method of switching and displaying the first focus information and the second focus information is also conceivable. As an example, even when the focusing lens 32 is driven using the measurement data acquired from the auto reflex, the first focus information is displayed at a position corresponding to the equivalent spherical power of the eye to be examined. By displaying on the monitor 8 that the focus adjustment has been performed (for example, focus adjustment based on the SE value of the eye to be examined has been performed) or that the focus adjustment has already been completed (for example, display of focus OK or the like). There may be a method of notifying the examiner that the focus adjustment has been made.

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 an example of a screen when the anterior ocular segment image imaged by the two-dimensional image sensor is displayed on the monitor. It is an example of a screen when the fundus image imaged by the two-dimensional image sensor is displayed on the monitor. It is a figure at the time of displaying 2nd focus information with a fundus observation image. It is a figure which expands and demonstrates 2nd focus information. It is a figure in the case of displaying the electronic graphic imitating two focus bars as 2nd focus information. It is a figure in the case of displaying the electronic graphic imitating two focus bars as 1st focus information. This is an example of switching the display form of two focus bars between the first focus mode and the second focus mode.

Explanation of symbols

8 monitor 30 fundus observation / imaging optical system 32 focusing lens 40 focus index projection optical system 49 moving mechanism 80 control unit 110 left and right eye discrimination unit

Claims (8)

A fundus photographing optical system having a drive mechanism for moving the focusing lens in the optical axis direction and photographing the fundus of the eye to be examined by an image sensor;
Eye refractive power measurement data acquisition means for acquiring measurement data including the astigmatism power of the subject's eye measured by an eye refractive power measurement device in a separate housing;
A focus detection means for detecting a focus state with respect to the subject's eye fundus by receiving a focusing light beam irradiated to the subject's eye fundus;
Control means for displaying the focus state obtained based on the detection result from the focus detection means on the monitor as the first focus information,
When driving the focusing lens using the measurement data acquired by the data acquisition means, the control means sets the focus completion position of the focusing lens to a position corresponding to the equivalent spherical power of the eye to be examined, and the setting A fundus photographing apparatus characterized in that focus information based on a position is switched and displayed on the monitor as second focus information different from the first focus information. The fundus imaging apparatus according to claim 1, further comprising: a second focus detection unit configured to detect a focus state with respect to the fundus of the subject's eye based on a moving position of the focusing lens corresponding to the equivalent spherical power of the subject's eye, and acquired by the data acquisition unit. When the focusing lens is driven using the measured data, the control means determines the amount of focus shift and the shift direction with respect to the fundus of the subject's eye obtained based on the detection result from the second focus detection means. A fundus imaging apparatus characterized by displaying information on a monitor. 3. The fundus imaging apparatus according to claim 2, further comprising an autofocus unit that automatically moves the focusing lens by controlling driving of the drive mechanism based on a detection result from the focus detection unit, and operating the autofocus unit. When the focusing lens is driven by the control unit, the control means displays the first focus information on a monitor. The control means according to claim 3 displays the two focus bars on the monitor as the first and second focus information, and drives the focusing lens by operating the autofocus means. While changing the separation direction and the separation amount of the two focus bars optically or electronically displayed on the monitor based on the detection result from the above, using the measurement data acquired by the data acquisition means When the focusing lens is driven, the fundus is characterized in that the separation direction and the separation amount of the two focus bars electronically displayed on the monitor are changed based on the detection result from the second focus detection means. Shooting device. 5. The control means according to claim 4, wherein two focus bars are electronically displayed on the monitor as the first and second focus information, and the focusing lens is driven by the operation of the auto focus means, and the data A fundus imaging apparatus, wherein the display mode of the two focus bars is switched between when the focusing lens is driven using measurement data acquired by an acquisition means. The control means according to claim 5 includes a case where the focusing lens is driven by the operation of the autofocus means and a case where the focusing lens is driven using the measurement data acquired by the data acquisition means. A fundus photographing apparatus characterized by changing at least one of the color, display position, separation direction, and shape of two focus bars electronically displayed on the screen. The fundus imaging apparatus according to claim 6, wherein
A first focus mode for setting a moving position of the focusing lens by the operation of the autofocus means as a focus completion position, and the focusing when the drive mechanism is driven and controlled based on the measurement data acquired by the data acquisition means A fundus photographing apparatus comprising: mode switching means for generating a mode switching signal for selectively switching between a second focus mode in which a lens movement position is set as a focus completion position. The fundus imaging apparatus according to claim 7, further comprising a determination unit that determines whether or not the astigmatism power of the eye to be examined in the measurement data acquired by the eye refractive power measurement data acquisition unit is within a predetermined range,
When the determination means determines that the astigmatism power of the eye to be examined is within a predetermined range, the control means selects the first focus mode by the mode switching means, and the determination means determines the astigmatism power of the eye to be examined. When it is determined that is out of a predetermined range, the second focus mode is selected by the mode switching means.

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