JP2009207572A - Fundus camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To acquire an appropriate fundus image by correcting astigmatism of a subject eye with a simple configuration. <P>SOLUTION: A fundus camera is provided which comprises a fundus imaging optical system having a focusing lens and a first driving mechanism for moving the focusing lens in an optical axis direction, an astigmatism correcting means having an astigmatism correcting optical member arranged in the optical path of the fundus imaging optical system for correcting astigmatism of a subject eye and a second driving mechanism for rotating the astigmatism correcting optical member around the optical axis so as to achieve a predetermined astigmatism degree and a predetermined astigmatism axis angle, a measurement data acquiring means for acquiring measurement data including an astigmatic degree and an astigmatic angularity of the subject eye measured by an eye refractive power measuring apparatus of a different enclosure, a focus detecting means for detecting focusing condition of the fundus, and a control means for driving and controlling the second driving mechanism on the basis of the astigmatic degree and the astigmatic angularity of the measurement data acquired by the acquiring means before carrying out auto-focusing by driving and controlling the first driving mechanism on the basis of the detection result of the detecting means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  Conventionally, a fundus camera that images 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 such a fundus camera, autofocusing is performed by moving the focusing lens in the optical axis direction based on the spherical power of the eye to be examined, which is obtained by an eye refractive power measurement device that objectively measures the refractive power of the eye to be examined. A configuration for setting an initial position of a focusing lens before starting is disclosed (see Patent Document 1). Further, it is disclosed that the focusing lens is moved by using the cylindrical power and the cylindrical axis angle of the eye to be examined in addition to the spherical power of the eye to be examined.

As another configuration, in addition to the focusing lens, two cylindrical lenses for correcting astigmatism are arranged in the optical path of the fundus photographing optical system, and two slit indexes orthogonal to each other are arranged on the fundus of the eye to be examined. And a light receiving optical system having a light receiving element for receiving two slit indexes projected onto the fundus, and based on a light reception signal from the light receiving element of the light receiving optical system, Astigmatism of the eye to be examined is detected by detecting the focus state in at least two meridian directions between the imaging element and driving the two cylindrical lenses and the focusing lens so that the detected slit index is in a predetermined positional relationship. In addition, a fundus camera that corrects a refractive error is disclosed (see Patent Document 2).
JP 2000-116603 A Japanese Patent Laid-Open No. 3-7135

  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, when a fundus image of an intense astigmatism eye is displayed, a blur of the fundus image that is not particularly noticeable on a small monitor screen may be noticeable and difficult to observe. Therefore, it is desired to correct the refractive error of the eye to be examined with high accuracy.

  However, the apparatus of Patent Document 1 does not have an optical system for correcting astigmatism of the subject's eye, and the cylindrical power and the cylindrical axis angle obtained by the eye refractive power measuring apparatus are the initial values of the focusing lens before autofocusing is performed. It is only used for setting the position, and it is difficult to correct astigmatism of the eye to be examined. In addition, in the apparatus of Patent Document 2, it is necessary to provide a special focus index projection optical system and focus index light receiving optical system in order to detect the focus state in the two meridian directions of the eye to be inspected, and the optical arrangement becomes complicated. End up.

  In view of the above problems, an object of the present invention is to provide a fundus camera that can correct astigmatism of a subject's eye with a simple configuration and obtain a suitable fundus image.

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

(1) A fundus photographing optical system that includes a focusing lens for focusing on the fundus of the eye to be examined and a first drive mechanism that moves the focusing lens in the optical axis direction, and photographs the fundus of the eye to be examined by an image sensor. The system,
An optical member for correcting astigmatism for correcting astigmatism of the eye to be examined; Astigmatism correction means having a second drive mechanism that rotates
Eye refractive power measurement data for acquiring measurement data including at least the astigmatism power and the astigmatic axis angle of the subject eye measured by an eye refractive power measuring device that is a separate housing and objectively measures the eye refractive power of the eye to be examined. Acquisition means;
Focus detection means for detecting a focus state between the eye fundus to be examined and the image sensor;
Based on the detection result from the focus detection unit, the first drive mechanism is driven and controlled to perform autofocus on the fundus of the subject's eye, before the eye refractive power measurement data acquisition unit obtains the measurement data obtained by the eye refractive power measurement data acquisition unit. Control means for driving and controlling the second drive mechanism based on the astigmatism power and the astigmatism axis angle.
(2) In the fundus camera of (1),
The measurement data acquired by the eye refractive power measurement data acquisition means further includes the spherical power of the eye to be examined,
The control means controls the first driving mechanism based on the detection result from the focus detection means and performs autofocus on the eye to be examined before measuring the eye in the measurement data obtained by the measurement data acquisition means. Driving the second drive mechanism based on the astigmatism power and the astigmatic axis angle, and controlling the first drive mechanism based on the spherical power of the eye to be examined in the measurement data obtained by the eye refractive power measurement data acquisition means. It is characterized by drive control.
(3) In the fundus camera of (2),
Comprising identification information input means for inputting identification information for identifying the subject,
The measurement data is measurement data associated with the identification information,
The eye refractive power measurement data acquisition means acquires measurement data corresponding to identification information input from the identification information input means from among measurement data of a plurality of subjects.
(4) In the fundus camera of (3),
Comprising left and right eye discriminating means for discriminating the left and right eyes of a subject imaged by the fundus imaging optical system;
The measurement data acquired by the eye refractive power data acquisition means is measurement data obtained from each of the subject's left and right eyes, and is measurement data in which the left and right eyes of each measurement data are determined,
The control means drives and controls the second drive mechanism based on the astigmatism power and the astigmatic axis angle of the eye to be examined in the measurement data corresponding to the discrimination result by the left and right eye discrimination means.
(5) In the fundus camera of (4),
After taking a picture of one eye of the subject, when taking a picture of the other eye,
The control means detects the switching of the left and right eyes based on the output signal from the left and right eye discriminating means, and sets the astigmatism power and the astigmatic axis angle of the eye to be examined in the measurement data corresponding to the eye to be newly discriminated as the photographing eye. Based on this, the second drive mechanism is driven and controlled.

  According to the present invention, astigmatism of the eye to be examined can be corrected with a simple configuration, and a suitable fundus image can be obtained.

  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 / Photographing Optical System> The fundus oculi observation / photographing optical system 30 includes an objective lens 25, a photographing diaphragm 31 positioned near the aperture of the perforated mirror 22, and two cylindrical lenses 91 having the same absolute value of refractive power. , 92, a focusing lens 32 movable in the optical axis direction, an imaging lens 33, and a flip-up mirror 34 that can be inserted / removed from the optical path by an insertion / removal mechanism 39 when photographing the fundus. The photographing optical system and the fundus observation optical system are objectives. The optical system from the lens 25 and the photographing aperture 31 to the imaging lens 33 is shared. 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 imaging optical path of the imaging optical system 30 between the focusing lens 32 and the two cylindrical lenses 91 and 92. When the eye to be examined has a strong refractive error, it is inserted into the optical path by a drive mechanism 89 that has a motor and performs the insertion / removal operation of the diopter correction lens 32a.

  The two cylindrical lenses 91 and 92 provided in the optical path of the fundus photographing optical system are used as an astigmatism correction optical member for correcting astigmatism of the eye to be examined. The two cylindrical lenses 91 and 92 are independently rotated around the optical axis L1 by driving rotational drive mechanisms (second drive mechanisms) 93 and 94 each having a motor, and have a predetermined astigmatism power and Get the astigmatic axis angle.

  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 cylindrical lenses 91 and 92, the focusing lens 32, the imaging lens 33, the flip-up mirror 34, and the dichroic. An image is formed on the image sensor 38 via the mirror 37 and the relay lens 36.

  Further, the fundus is illuminated with visible light by the light emission of the photographing light source 14, and the reflected light from the fundus is reflected by the objective lens 25, the aperture of the perforated mirror 22, the photographing diaphragm 31, the cylindrical lenses 91 and 92, the focusing lens 32, and the connection lens. An image is formed on the two-dimensional image sensor 35 through the image lens 33 and the flip-up mirror 34.

  <Focus Index Projection Optical System> Further, as an optical system for detecting the focus state of the eye to be examined, a light source that emits a projection light beam for projecting a focus index to the fundus of the eye to be examined is emitted from the light source. An index projection optical system 40 for projecting the projected light beam onto the fundus of the subject's eye and a light receiving optical system (fundus observation) for receiving the fundus reflection light beam by the projection beam projected onto the eye fundus of the eye to be examined by the index projection optical system 40 An optical system 30) is provided.

  More specifically, the focus index projection optical system 40 includes an infrared light source 41, a slit index plate 42, two deflection prisms 43 attached to the slit index plate 42, a projection lens 47, and an optical path of the illumination optical system 10. A spot mirror 44 is provided obliquely. 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 fundus observation imaging element 38 (see FIG. 4).

  <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 cylindrical lenses 92 and 91, the perforated mirror 22, the dichroic mirror 24, and the objective lens 25. Then, the light is condensed on the fundus of the eye to be examined, 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 emits a moving mechanism 49, an insertion / removal mechanism 39, an insertion / removal mechanism 66, rotation drive mechanisms 93, 94, a drive mechanism 89, a rotation knob 4a provided on the joystick 4, and a shooting start trigger. A photographing switch 4b, a switch unit 84 having various switches, a memory 85 as a storage means, a connector 86, each light source, and the like are connected. 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 changeover switch 84c for inserting / removing the lens is 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. First, the examiner objectively measures the eye refractive power of the subject's eye objectively before starting imaging of the fundus of the subject's eye (hereinafter abbreviated as “autoref”). To obtain the eye refractive power measurement data (for example, spherical power (S), astigmatism power (C), astigmatism axis angle (A)) of the corresponding eye, and use the acquired measurement data before fundus photography. Input to this device.

  Here, the control unit 80 acquires measurement data input to the apparatus and stores the measurement data in the memory 85. For example, when a portable storage medium (for example, a USB memory, an IC card, or the like) storing measurement data measured by auto-ref is connected to the connector unit 86 as a measurement data input unit of the present apparatus, the control is performed. The unit 80 performs a measurement data reading operation and stores the measurement data in the memory 85. In addition, measurement data is transmitted from the auto reflex to the device by wired communication (for example, connecting the auto reflex to the device with a LAN cable) or wireless communication (for example, providing a wireless LAN transmission / reception unit for exchanging information). The measurement data transferred from the auto-ref may be stored in the memory 85 with a transferable configuration.

  The input measurement data is associated with an ID number used as identification information for identifying the subject, and when a plurality of measurement data is input, the measurement data for each subject is It is stored in the memory 85 in a format that can be discriminated. Furthermore, measurement data that can be discriminated for each subject has measurement data obtained from the left and right eyes of the subject, and is stored in the memory 85 in a format in which the left and right eyes of each measurement data are discriminated.

  Next, 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. When there is no eye refractive power measurement data of the eye to be examined, the control unit 80 keeps the focusing lens 32 and the cylindrical lenses 90 and 91 in an initial state (a state where S = 0 and C = 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.

  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.

  Then, the control unit 80 moves the focusing lens 32 and the cylindrical lenses 91 and 92 based on the measurement data corresponding to the left and right eye discrimination result based on the discrimination result discriminated by the left and right eye discrimination unit 110. More specifically, when the eye to be examined is determined to be the right eye by the left and right eye determination unit 110, the control unit 80, based on the measurement data of the right eye, outputs a driving signal (for example, a moving mechanism 49 corresponding to the right eye). The movement amount from the reference position) and the driving signals of the rotation mechanisms 93 and 94 (for example, the rotation amount from the reference position) are acquired from the memory 85. Then, the controller 80 controls the movement mechanism 49 and the rotation mechanisms 93 and 94 based on the acquired drive signals to move the focusing lens 32 and the cylindrical lenses 91 and 92 in each direction.

  Here, the control unit 80 drives the rotation driving mechanisms 93 and 94 so that the astigmatism state of the subject eye is corrected based on the astigmatism power and the astigmatic axis angle of the subject eye (right eye) included in the measurement data. Control. For example, in the acquired eye refractive power measurement data (hereinafter abbreviated as measurement data), when the astigmatism power of the eye to be examined is C = −2.0D and the astigmatism axis angle is A = 90 °, the cylindrical lens 91 and 92 may have optical characteristics of C = −2.0D and A = 90 °.

  Further, the control unit 80 operates the moving mechanism 49 so that the spherical refraction error of the eye to be examined is corrected based on the spherical power of the eye to be examined included in the measurement data. For example, in the acquired measurement data, when the spherical power of the eye to be examined is S = −3.0D, the control unit 80 sets the focusing lens 32 arranged at the position corresponding to 0D as the reference position to −3.0D. Move to the corresponding position.

  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.

  Note that the drive signals (drive information) of the moving mechanism 49 and the rotating mechanisms 93 and 94 corresponding to the eye refractive power measurement data of the eye to be examined are calculated in advance and stored in the memory 85. In this case, because of the characteristics of the cylindrical lenses 91 and 92, the spherical power of the cylindrical lenses 91 and 92 varies depending on the astigmatic power (cylindrical power) of the cylindrical lenses 91 and 92. Therefore, in addition to the spherical power of the eye to be examined, astigmatism. It is necessary to set the drive signal of the moving mechanism 49 in consideration of the amount of change in spherical power of the cylindrical lenses 91 and 92 due to the change in power.

  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. 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.

  After finely adjusting the alignment by observing the fundus image, as shown in FIG. 4, focus index images S1 and S2 by the focus index projection optical system 40 are projected at the center. Then, the focusing lens 32 and the slit indicator plate 42 are moved in the optical axis direction to focus the fundus. 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. Focusing can be done manually by the examiner's operation, but in this apparatus, the autofocus mode is set.

  Here, when the driving of the moving mechanism 49 and the rotation driving mechanisms 93 and 94 based on the above-described eye refractive power measurement data is stopped, the control unit 80 issues a permission signal that permits execution of autofocus 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. In this case, the focus index images S1 and S2 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. To focus the fundus.

  As described above, the control unit 80 drives the rotation drive mechanisms 93 and 94 based on the astigmatism power and the astigmatism axis angle of the eye to be examined in the measurement data acquired from the auto-ref before performing autofocus on the eye fundus. Control is set to correct astigmatism of the eye to be examined. In addition, in the present embodiment, in addition to this, before performing autofocus on the fundus of the eye to be examined, the movement mechanism 49 is driven and controlled based on the spherical power of the eye to be examined in the measurement data to refract the spherical component of the eye to be examined. It is set to correct the abnormality.

  In this case, since the diopter correction of the eye to be examined is performed in advance by the movement of the focusing lens 32 and the rotational movement of the cylindrical lenses 91 and 92 based on the above-described eye refractive power data, the autofocus control is performed by the eye refractive power measuring device. The remaining refractive error of the eye to be examined is corrected by the measurement error in the lens and the error in the optical characteristics of the photographing optical system of the fundus camera.

  In addition, after the focusing is completed as described above, the examiner presses the photographing switch 84b to perform photographing. When the trigger signal of the photographing switch 4b is input, the control unit 80 drives the insertion / removal mechanism 66 to detach the dichroic mirror 24 from the optical path and emit the photographing light source 14. 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. Here, when photographing the left eye after photographing the right eye of the eye to be examined, the control unit 80 detects the switching of the left and right eyes based on the output signal from the left and right eye discriminating unit 110 and newly creates a photographing eye. The movement mechanism 49 and the rotation mechanisms 93 and 94 are driven and controlled based on the measured data corresponding to the determined eye to be examined.

  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 drives and controls the moving mechanism 49 and the rotation mechanisms 93 and 94 based on the measurement data of the left eye acquired from the memory 85, as in the case of the right eye, so that the focusing lens 32 and the cylinder are driven. The lenses 91 and 92 are moved. The following description is performed by the same method as that for right-eye photography, and thus the description thereof is omitted.

  With the above-described configuration, the astigmatism state of the eye to be examined can be corrected by a simple focus index projection optical system, so that a clear fundus image can be taken even if the eye to be examined is an astigmatic eye. In addition, by performing astigmatism correction of the eye to be examined by the cylindrical lenses 91 and 92 before performing autofocus, the focus state can be detected in a state in which the distortion of the focus index due to the effect of astigmatism is removed. Focus can be done. In addition, if the cylindrical lenses 91 and 92 are rotated around the optical axis L1 and the astigmatism correction is performed after the autofocus is performed, the focusing lens 32 needs to be moved again (since the cylindrical lens has an S value), the focusing is performed. Although there is a possibility that the focus may be shifted due to an error in the movement amount of the lens 32, such a problem can be avoided if the astigmatism correction by the cylindrical lenses 91 and 92 is executed in advance.

  Note that the diopter correction control based on the eye refractive power measurement data of the eye to be examined uses the spherical power, astigmatism power, and astigmatic axis angle of the eye to be examined in the above description, but at least the astigmatism power of the eye to be examined and What is necessary is just to correct the astigmatic state of the eye to be examined by rotating the cylindrical lenses 91 and 92 around the optical axis L1 based on the astigmatic axis angle. For example, the focus index projected on the subject's eye while the cylindrical lenses 91 and 92 are rotated around the optical axis L1 based on the astigmatism power and the astigmatic axis angle of the subject's eye and the astigmatism state of the subject's eye is corrected in advance. The refractive error of the spherical power component of the eye to be inspected may be corrected by detecting autofocus control.

  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 and cylindrical lenses 91 and 92 are moved.

  In the above configuration, the control unit 80 determines whether or not the astigmatism power of the eye to be inspected input from the auto reflex is equal to or greater than a predetermined value (for example, equal to or greater than −1D), and is determined to be equal to or greater than the predetermined value. In this case, the cylindrical lenses 91 and 92 may be rotated about the optical axis L1 based on the astigmatism power and the astigmatic axis angle.

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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 30 Fundus observation / imaging optical system 32 Focusing lens 40 Focus index projection optical system 49 Moving mechanism 80 Control unit 91, 92 Cylindrical lens 93, 94 Rotation drive mechanism 110 Left and right eye discrimination unit

Claims (5)

A fundus photographing optical system that has a focusing lens for focusing on the fundus of the eye to be examined, and a first drive mechanism that moves the focusing lens in the optical axis direction, and photographs the fundus of the eye to be examined by an image sensor;
An optical member for correcting astigmatism for correcting astigmatism of the eye to be examined; Astigmatism correction means having a second drive mechanism that rotates
Eye refractive power measurement data for acquiring measurement data including at least the astigmatism power and the astigmatic axis angle of the subject eye measured by an eye refractive power measuring device that is a separate housing and objectively measures the eye refractive power of the eye to be examined. Acquisition means;
Focus detection means for detecting a focus state between the eye fundus to be examined and the image sensor;
Based on the detection result from the focus detection unit, the first drive mechanism is driven and controlled to perform autofocus on the fundus of the subject's eye, before the eye refractive power measurement data acquisition unit obtains the measurement data obtained by the eye refractive power measurement data acquisition unit. A fundus camera comprising: control means for driving and controlling the second drive mechanism based on an astigmatism power and an astigmatism axis angle. The fundus camera of claim 1,
The measurement data acquired by the eye refractive power measurement data acquisition means further includes the spherical power of the eye to be examined,
The control means controls the first driving mechanism based on the detection result from the focus detection means and performs autofocus on the eye to be examined before measuring the eye in the measurement data obtained by the measurement data acquisition means. Driving the second drive mechanism based on the astigmatism power and the astigmatic axis angle, and controlling the first drive mechanism based on the spherical power of the eye to be examined in the measurement data obtained by the eye refractive power measurement data acquisition means. Fundus camera characterized by driving control. The fundus camera of claim 2,
Comprising identification information input means for inputting identification information for identifying the subject,
The measurement data is measurement data associated with the identification information,
The fundus camera, wherein the eye refractive power measurement data acquisition unit acquires measurement data corresponding to identification information input from the identification information input unit from among measurement data of a plurality of subjects. The fundus camera of claim 3.
Left and right eye discriminating means for discriminating the left and right eyes of a subject imaged by the fundus imaging optical system,
The measurement data acquired by the eye refractive power data acquisition means is measurement data obtained from each of the subject's left and right eyes, and is measurement data in which the left and right eyes of each measurement data are determined,
The fundus camera characterized in that the control means drives and controls the second drive mechanism based on the astigmatism power and the astigmatism axis angle of the eye to be examined in the measurement data corresponding to the discrimination result by the left and right eye discrimination means. The fundus camera of claim 4,
After taking a picture of one eye of the subject, when taking a picture of the other eye,
The control means detects the switching of the left and right eyes based on the output signal from the left and right eye discriminating means, and sets the astigmatism power and the astigmatic axis angle of the eye to be examined in the measurement data corresponding to the eye to be newly discriminated as the photographing eye. A fundus camera characterized in that the second drive mechanism is driven based on the control.

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