JP2018110691A - Ophthalmologic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new technique for alignment for an ophthalmologic apparatus.SOLUTION: An ophthalmologic apparatus of an embodiment is configured so that a data acquisition optical system acquires data of an eye to be examined. Two or more imaging parts are configured to image an anterior eye part of the eye to be examined from different directions, respectively. A first alignment part is configured to acquire first alignment information for performing alignment of the data acquisition optical system with a cornea of the eye to be examined as a reference. A second alignment part is configured to acquire second alignment information for alignment of the data acquisition optical system with a prescribed portion on the eye to be examined as a reference, based on two or more picked up images acquired by the two or more imaging parts. A position determination part is configured to determine a movement target position of the data acquisition optical system based on the first alignment information and the second alignment information.SELECTED DRAWING: Figure 4A

Description

  The present invention relates to an ophthalmic apparatus.

  The ophthalmologic apparatus includes an ophthalmologic photographing apparatus for obtaining an image of the eye to be examined and an ophthalmologic measuring apparatus for measuring the characteristics of the eye to be examined.

  As an example of an ophthalmologic photographing apparatus, an optical coherence tomography (Optical Coherence Tomography, OCT) is used to obtain a tomographic image, a fundus camera for photographing a fundus, a fundus image obtained by laser scanning using a confocal optical system. There is a scanning laser opthalmoscope (SLO).

  Examples of ophthalmic measuring devices include an ocular refraction examination device (refractometer, keratometer) that measures the refractive characteristics of the eye to be examined, a tonometer, a specular microscope that obtains corneal properties (corneal thickness, cell distribution, etc.), Hartmann There is a wave front analyzer that obtains aberration information of the eye to be examined using a shack sensor.

  In ophthalmic examination, alignment between the apparatus optical system and the eye to be examined is extremely important from the viewpoint of accuracy and accuracy of examination. This alignment is called alignment. The alignment includes an operation for aligning the optical axis of the apparatus optical system with the axis of the eye to be examined (xy alignment) and an operation for adjusting the distance between the eye to be examined and the apparatus optical system (z alignment).

  There are various methods for alignment. As a typical technique, a technique is known in which a light beam is projected onto the cornea, and a reflected image (Purkinje image) is detected to perform alignment (see, for example, Patent Document 1).

  As a technique realized in recent years, the three-dimensional position of the eye to be examined is specified from two or more photographed images obtained by photographing the anterior segment from different directions, and xy alignment and z alignment are performed based on the three-dimensional position. There is a method of performing both of these (for example, see Patent Document 2).

  On the other hand, in an ophthalmologic apparatus that projects illumination light over a relatively wide area of the fundus, such as a fundus camera, in order to prevent noise light (flares, ghosts, etc.) caused by reflection from the cornea or crystalline lens, A ring-shaped aperture stop for limiting the transmission area of the illumination light at the site is provided.

  For example, the fundus camera disclosed in Patent Document 3 includes a corneal diaphragm, an iris diaphragm (lens front diaphragm), and a lens rear diaphragm each having a ring-shaped opening. Further, the fundus camera is configured to detect the flare state in at least one of the cornea, the iris, and the rear surface of the lens and to control the movement of the diaphragm. According to this configuration, there is an advantage that noise light can be removed regardless of individual differences in the position of the cornea, iris, lens back surface, and the like. However, there is a demerit that it takes a relatively long time to guide all the apertures to a suitable position.

Japanese Patent Laid-Open No. 8-27592 JP 2013-248376 A JP 2002-224039 A

  Thus, when the conventional alignment method is used, the following problems may occur.

  For example, the Purkinje image is formed at a position displaced in the axial direction (z direction) from the corneal apex by a distance that is a half of the corneal curvature radius. In addition, the cornea and the pupil may be eccentric with respect to the visual axis (that is, the corneal apex position may not match the pupil center position in the xy direction). Therefore, depending on the degree of eccentricity between the cornea and the pupil, if the alignment is performed based on the Purkinje image (that is, the cornea), the light beam may be vignetted by the iris. On the other hand, when alignment is performed based on the pupil, there is a high possibility that noise light resulting from reflection at the cornea is mixed.

  Furthermore, in an ophthalmologic apparatus provided with a ring-shaped aperture stop corresponding to a cornea or a crystalline lens, it is difficult to suitably perform z alignment. For example, there are individual differences in the arrangement of the eye part, such as the depth of the anterior chamber. When z alignment is performed with reference to the cornea, the corneal diaphragm can effectively remove reflection from the cornea. However, the iris diaphragm and the lens rear diaphragm may not fully function. On the other hand, when the alignment is performed based on the pupil, the iris diaphragm can effectively remove reflection on the front surface of the lens. However, when the anterior chamber depth of the eye to be examined is unique, the corneal diaphragm may not fully perform its function. In addition, when the lens thickness of the eye to be examined is unique, the lens rear surface diaphragm may not fully perform its function. Although the position of each diaphragm can be adjusted as in the fundus camera disclosed in Patent Document 3, the structure is complicated and there is a possibility that the inspection may take a long time.

  An object of the present invention is to provide a new method of alignment for an ophthalmic apparatus.

The ophthalmologic apparatus according to the first aspect of the embodiment includes a data acquisition optical system, two or more imaging units, a first alignment unit, a second alignment unit, and a position determination unit. The data acquisition optical system is configured to acquire data of the eye to be examined. The two or more imaging units are configured to image the anterior segment of the eye to be examined from different directions. The first alignment unit is configured to acquire first alignment information for performing alignment of the data acquisition optical system with reference to the cornea of the eye to be examined. The second alignment unit acquires second alignment information for performing alignment of the data acquisition optical system with reference to a predetermined part of the eye to be examined based on two or more captured images acquired by the two or more imaging units. Configured. The position determination unit is configured to determine a movement target position of the data acquisition optical system based on the first alignment information and the second alignment information.
In the ophthalmologic apparatus according to the second aspect of the embodiment, the position determination unit is configured to compare the first alignment information and the second alignment information. Furthermore, the position determination unit is configured to determine a movement target position based on the first alignment information and the second alignment information when the comparison result satisfies a predetermined condition.
In the ophthalmic apparatus according to the third aspect of the embodiment, the first alignment information includes a first position acquired with reference to the cornea, and the second alignment information is a second position acquired with reference to a predetermined part. including. Further, the position determining unit is configured to calculate a difference between the first position and the second position, and to determine a movement target position based on the first position and the second position when the difference is larger than a predetermined threshold value. Is done.
In the ophthalmologic apparatus according to the fourth aspect of the embodiment, the position determination unit is configured to obtain a position between the first position and the second position. Further, the position determination unit is configured to determine a movement target position based on the position.
In the fifth aspect of the embodiment, the predetermined part is a pupil, and the ophthalmologic apparatus includes a pupil size information acquisition unit that acquires information indicating the pupil size of the eye to be examined. Further, the position determination unit is configured to move the data acquisition optical system based on the position corresponding to the second alignment information when the pupil size represented by the information acquired by the pupil size information acquisition unit is equal to or smaller than a predetermined threshold. Configured to determine a position.
In the ophthalmologic apparatus according to the sixth aspect of the embodiment, the pupil size information acquisition unit includes an anterior ocular segment imaging system and a pupil size calculation unit. The anterior segment imaging system is configured to capture the anterior segment of the eye to be examined. The pupil size calculating unit is configured to calculate the pupil size by analyzing the anterior segment image acquired by the anterior segment imaging system.
The ophthalmologic apparatus according to the seventh aspect of the embodiment includes a fixation optical system that outputs fixation light for rotating the eye to be examined from the central fixation position. The position determination unit is configured to determine a movement target position of the data acquisition optical system based on a position corresponding to the first alignment information when fixation light is output from the fixation optical system.
In the ophthalmologic apparatus according to the eighth aspect of the embodiment, the first alignment unit is configured to acquire first alignment information based on two or more captured images acquired by two or more imaging units.
In the ophthalmologic apparatus according to the ninth aspect of the embodiment, the first alignment unit includes a light beam projection optical system that projects an alignment light beam onto the cornea of the eye to be examined. Furthermore, the first alignment unit is configured to generate first alignment information by analyzing two or more captured images acquired by the two or more imaging units when the alignment light beam is projected onto the cornea. .
The ophthalmologic apparatus according to the tenth aspect of the embodiment includes a first drive unit and a first control unit. The first drive unit is configured to move the data acquisition optical system. The first control unit is configured to control the first drive unit based on the movement target position determined by the position determination unit.
The ophthalmologic apparatus according to the eleventh aspect of the embodiment includes a second control unit, an operation unit, and a second drive unit. The second control unit is configured to cause the display unit to display information based on the movement target position determined by the position determination unit. The operation unit is configured to receive an operation for moving the data acquisition optical system. The second drive unit is configured to move the data acquisition optical system in accordance with an operation performed using the operation unit.
In the ophthalmologic apparatus according to the twelfth aspect of the embodiment, the data acquisition optical system includes an illumination optical system and a photographing optical system. The illumination optical system includes a first diaphragm corresponding to the cornea and a second diaphragm corresponding to a predetermined intraocular region. Furthermore, the illumination optical system is configured to project illumination light onto the fundus of the eye to be examined. The imaging optical system is configured to guide the return light of the illumination light projected onto the fundus by the illumination optical system to the image sensor.
Any two or more of the above aspects can be combined. Further, any known technique can be combined with any of the above-described aspects, or at least a part of any of the above-described aspects can be replaced with any known technique.

  According to the present invention, it is possible to provide a new method of alignment for an ophthalmologic apparatus.

It is a schematic diagram showing an example of composition of an ophthalmology device concerning an embodiment. It is a schematic diagram showing an example of composition of an ophthalmology device concerning an embodiment. It is a schematic diagram showing an example of composition of an ophthalmology device concerning an embodiment. It is a schematic diagram showing an example of composition of an ophthalmology device concerning an embodiment. It is a schematic diagram showing an example of composition of an ophthalmology device concerning an embodiment. It is a schematic diagram showing an example of composition of an ophthalmology device concerning an embodiment. It is a schematic diagram showing an example of composition of an ophthalmology device concerning an embodiment. It is the schematic for demonstrating an example of the process which the ophthalmologic apparatus which concerns on embodiment can perform. It is the schematic for demonstrating an example of the process which the ophthalmologic apparatus which concerns on embodiment can perform. It is the schematic for demonstrating an example of the process which the ophthalmologic apparatus which concerns on embodiment can perform. It is a flowchart showing an example of the operation | movement which the ophthalmologic apparatus which concerns on embodiment can perform. It is a flowchart showing an example of the operation | movement which the ophthalmologic apparatus which concerns on embodiment can perform.

  An example of an embodiment of an ophthalmologic apparatus according to the present invention will be described in detail with reference to the drawings. The ophthalmologic apparatus according to the embodiment is used for optical examination of an eye to be examined. Such an ophthalmologic apparatus includes, for example, at least one of an ophthalmologic photographing apparatus and an ophthalmologic measurement apparatus. Examples of ophthalmic imaging apparatuses include an optical coherence tomometer, a fundus camera, and a scanning laser ophthalmoscope. Examples of the ophthalmologic measurement apparatus include an eye refraction inspection apparatus, a tonometer, a specular microscope, and a wave front analyzer. In the following embodiment, the ophthalmologic apparatus is a combined machine of an optical coherence tomography and a fundus camera. However, the same configuration can be applied to other ophthalmologic apparatuses. In addition, arbitrary well-known techniques including the technique disclosed by the literature referred by this specification can be combined with embodiment.

  In the following embodiments, a so-called Spectral Domain type optical coherence tomography equipped with a low-coherence light source and a spectroscope will be described. However, the OCT type applicable to the embodiment is not limited to the spectral domain type. For example, the same configuration can be applied to a swept source type optical coherence tomography.

  Here, the swept source OCT is the interference light obtained by scanning the wavelength of the light projected on the object to be measured (wavelength sweep) and superimposing the reflected light of each wavelength and the reference light. Are sequentially detected to obtain a spectral intensity distribution, and a Fourier transform is performed on the spectral intensity distribution, thereby imaging the form of the object to be measured. In a typical swept source OCT, the light source is a tunable light source and the photodetector is a balanced photodiode.

<Constitution>
The ophthalmologic apparatus 1 illustrated in FIG. 1 includes a fundus camera unit 2, an OCT unit 100, and an arithmetic control unit 200. The retinal camera unit 2 has almost the same optical system as a conventional retinal camera. The OCT unit 100 is provided with an optical system for acquiring an OCT image of the fundus. The arithmetic control unit 200 includes a processor that executes various types of information processing.

  The “processor” is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), or a programmable logic device (for example, SPLD (Simple ProgramLD). Device), FPGA (Field Programmable Gate Array)) and the like. The processor implements the functions according to the embodiment by, for example, reading and executing a computer program stored in a storage circuit or a storage device.

<Fundus camera unit 2>
The fundus camera unit 2 shown in FIG. 1 is provided with an optical system for obtaining a two-dimensional image (fundus image) representing the surface form of the fundus oculi Ef of the eye E to be examined. The fundus image includes an observation image and a captured image. The observation image is, for example, a monochrome moving image formed at a predetermined frame rate using near infrared light. In addition, when the optical system is focused on the anterior segment Ea of the eye E, the fundus camera unit 2 can obtain an observation image of the anterior segment Ea. The captured image may be, for example, a color image obtained by flashing visible light, or a monochrome still image using near infrared light or visible light as illumination light. The fundus camera unit 2 may be configured to be able to acquire images other than these, for example, a fluorescein fluorescent image, an indocyanine green fluorescent image, a spontaneous fluorescent image, and the like.

  The retinal camera unit 2 is provided with a chin rest and a forehead support for supporting the subject's face. The chin rest and the forehead support correspond to the support portion 440 shown in FIGS. 5A and 5B. In FIG. 5A and FIG. 5B, reference numeral 410 denotes a drive system such as the optical system drive unit 2A and a base in which an arithmetic control circuit is stored. Reference numeral 420 denotes a housing provided on the base 410 and storing an optical system. Reference numeral 430 denotes a lens housing portion that is provided on the front surface of the housing 420 and accommodates the objective lens 22.

  The fundus camera unit 2 is provided with an illumination optical system 10 and a photographing optical system 30. The illumination optical system 10 projects illumination light onto the fundus oculi Ef. The imaging optical system 30 guides the return light of the illumination light to an imaging device (CCD image sensor (sometimes simply referred to as a CCD) 35, 38). The imaging optical system 30 guides the signal light from the OCT unit 100 to the fundus oculi Ef and guides the signal light passing through the fundus oculi Ef to the OCT unit 100.

  The illumination optical system 10 is provided with a stop for preventing noise light from being mixed due to reflection at a predetermined site of the eye E. In this example, similarly to Patent Document 3, a lens front diaphragm 23f, a lens rear diaphragm 23r, and a corneal diaphragm 23c are provided. The front lens diaphragm 23f spatially separates the light beam incident on the eye E and traveling toward the fundus Ef and the light beam reflected from the fundus Ef and emitted from the eye E on the front surface (corner side surface) of the lens. This is a stop for preventing the reflected light of the incident light beam from the front surface of the crystalline lens from entering the photographing optical system 30. The lens front diaphragm 23f is a diaphragm for preventing flare caused by the incident light beam projected on the iris. Similarly, the lens rear surface stop 23 r is a stop for preventing the reflected light from the rear surface (surface on the retina side) of the lens from entering the photographing optical system 30. The corneal stop 23 c is a stop for preventing the reflected light from the cornea from entering the photographing optical system 30.

  A ring-shaped (annular) opening is formed in each of the lens front diaphragm 23f, the lens rear diaphragm 23r, and the cornea diaphragm 23c. An example of the lens front diaphragm 23f is shown in FIG. The lens front diaphragm 23f is, for example, a plate-like member made of a light-shielding material, and includes a ring-shaped opening 23t through which light can pass. The ring-shaped opening 23t is, for example, a ring-shaped plate-shaped member formed of a ring-shaped through hole or a transparent material. In another example, the crystalline lens front stop 23f is a plate-like member formed of a light-transmitting material, and a surface treatment that imparts light shielding properties to a region other than the ring-shaped opening 23t is performed. The disc-shaped light shielding area provided inside the ring-shaped opening 23t and the ring-shaped light shielding area provided outside the ring-shaped opening 23t are configured to transmit light beams projected onto the corresponding light-shielding areas on the lens surface. Acts as a block. The configuration of the lens front diaphragm 23f is not limited to these examples. The lens rear diaphragm 23r and the corneal diaphragm 23c also have the same configuration as in FIG.

  The lens front diaphragm 23f is arranged so that the center of the disk-shaped light shielding region inside the ring-shaped opening 23t is positioned on the optical axis of the illumination optical system 10. The same applies to the lens rear diaphragm 23r and the cornea diaphragm 23c.

  The positional relationship among the lens front diaphragm 23f, the lens rear diaphragm 23r, and the cornea diaphragm 23c is designed according to the positional relationship between the cornea, the lens front surface, and the lens rear surface in a standard eye. For example, considering the optical conjugate relationship, the optical distance between the corneal diaphragm 23c and the lens front diaphragm 23f is designed according to the standard value of the anterior chamber depth, and between the lens front diaphragm 23f and the lens rear diaphragm 23r. The optical distance is designed according to the standard value of the lens thickness. The standard value is, for example, a model eye value, a clinically obtained value, or a statistically obtained value. The standard value of the anterior chamber depth is set to 3.0 millimeters or 3.1 millimeters, for example. The standard value of the lens thickness is set to, for example, 3.5 millimeters or 3.6 millimeters.

  When both the anterior chamber depth and the lens thickness of the eye E are close to the standard values, the corneal diaphragm 23c is substantially disposed at a position optically conjugate with the cornea of the eye E in an aligned state. The lens front diaphragm 23f is disposed at a position optically conjugate with the lens front surface of the eye E, and the lens rear diaphragm 23r is disposed at a position optically conjugate with the lens rear surface of the eye E.

  On the other hand, when at least one of the anterior chamber depth and the lens thickness of the eye E is deviated from the standard value, any one of the lens front diaphragm 23f, the lens rear diaphragm 23r, and the corneal diaphragm 23c is set to the corresponding portion. It deviates from the optically conjugate position. For example, when the difference between the anterior chamber depth of the eye E and the standard value is large, at least the lens front diaphragm 23f deviates from the conjugate position when the cornea is used as a reference. Further, when the difference between the anterior chamber depth of the eye E to be examined and the standard value is large, at least the corneal diaphragm 23c deviates from the conjugate position when the pupil (front surface of the crystalline lens) is aligned as a reference.

  The observation light source 11 of the illumination optical system 10 is composed of, for example, a halogen lamp. The light (observation illumination light) output from the observation light source 11 is reflected by the reflection mirror 12 having a curved reflecting surface, passes through the condensing lens 13, passes through the visible cut filter 14, and becomes near infrared light. , And projected onto the lens front diaphragm 23f. Part of the projected observation illumination light passes through the ring-shaped opening 23t of the lens front diaphragm 23f. The observation illumination light that has passed through the lens front diaphragm 23f is projected onto the lens rear diaphragm 23r. Part of the projected observation illumination light passes through the ring-shaped opening (23t) of the lens rear diaphragm 23r. The observation illumination light that has passed through the lens rear diaphragm 23r is reflected by the mirror 16 and is projected to the corneal diaphragm 23c via the relay lens 17, the relay lens 18, the diaphragm 19, and the relay lens 20. Part of the projected observation illumination light passes through the ring-shaped opening (23t) of the corneal stop 23c. The observation illumination light that has passed through the corneal stop 23c is reflected by the peripheral portion (region around the hole portion) of the aperture mirror 21, passes through the dichroic mirror 46, and is refracted by the objective lens 22 to illuminate the fundus oculi Ef. . An LED (Light Emitting Diode) can also be used as the observation light source.

  The return light of the observation illumination light projected on the fundus oculi Ef is refracted by the objective lens 22, passes through the dichroic mirror 46, passes through the hole formed in the central region of the aperture mirror 21, and passes through the focusing lens 31. And is reflected by the mirror 32. Further, the return light passes through the half mirror 39A, is reflected by the dichroic mirror 33, and forms an image on the light receiving surface of the CCD image sensor 35 by the condenser lens. The CCD image sensor 35 detects the return light at a predetermined frame rate, for example. The display device 3 displays an image (observation image) based on the return light detected by the CCD image sensor 35. When the photographing optical system is focused on the anterior segment, an observation image of the anterior segment Ea of the eye E is displayed. The observation image is an example of a front image obtained by photographing the anterior segment Ea from the front of the subject.

  The imaging light source 15 is constituted by, for example, a xenon lamp. The light (imaging illumination light) output from the imaging light source 15 is projected onto the fundus oculi Ef through the same path as the observation illumination light. The return light of the imaging illumination light projected on the fundus oculi Ef is guided to the dichroic mirror 33 through the same path as that of the observation illumination light, passes through the dichroic mirror 33, is reflected by the mirror 36, and is reflected by the condenser lens 37. An image is formed on the light receiving surface of the CCD image sensor 38. An image (captured image) based on the return light detected by the CCD image sensor 38 is displayed on the display device 3. An LED may be used as the photographing light source 15. If the CCD image sensor 38 is sensitive to near-infrared light and can shoot a moving image, the image sensor 38 can also obtain an observation image in the near-infrared. In this case, the half mirror 33, the imaging lens 34, and the CCD image sensor 35 may not be provided.

  An LCD (Liquid Crystal Display) 39 is illuminated by a backlight or the like provided on the back side, and displays a fixation target and an eyesight measurement index. The fixation target is an index for fixing the eye E to be examined, and is used at the time of fundus photographing or OCT measurement.

  A part of the light output from the LCD 39 is reflected by the half mirror 39A, reflected by the mirror 32, passes through the focusing lens 31, passes through the hole of the perforated mirror 21, and passes through the dichroic mirror 46. Then, the light is refracted by the objective lens 22 and projected onto the fundus oculi Ef.

  By changing the display position of the fixation target on the screen of the LCD 39, the projection direction of the fixation target with respect to the eye E, that is, the fixation position of the eye E can be changed. Thereby, the eye E can be rotated.

  The means for projecting the fixation target onto the eye E is not limited to this. For example, the fixation position can be changed by providing an LED group formed by arranging a plurality of LEDs and selectively lighting these LEDs. It is also possible to change the fixation position by providing one or more movable LEDs.

  The fundus camera unit 2 is provided with a light beam projection optical system 50 for projecting an alignment light beam onto the anterior eye portion Ea (cornea) of the eye E to be examined. The light beam projection optical system 50 projects a light beam for obtaining a Purkinje image onto the anterior eye portion Ea. The light beam projection optical system 50 includes an alignment light source 51. The alignment light source 51 is, for example, an LED, and is disposed near the focal position of the objective lens 22 or at a position optically conjugate with it.

  The alignment light beam output from the alignment light source 51 is reflected by the dichroic filter 52. The dichroic filter 52 is disposed between the relay lens 45 and the dichroic mirror 46 and synthesizes the optical path from the alignment light source 51 and the optical path of the signal light from the OCT unit 100. The dichroic filter 52 has a characteristic of reflecting the alignment light flux and transmitting signal light for OCT measurement.

  The alignment light beam reflected by the dichroic filter 52 travels along the optical path of the signal light, is reflected by the dichroic mirror 46, and is projected onto the anterior eye portion Ea via the objective lens 22. Thereby, a Purkinje image is formed in the anterior segment Ea.

  The position where the light beam projection optical system 50 is provided is not limited to the configuration shown in FIG. For example, a dichroic filter can be disposed between the perforated mirror 21 and the focusing lens 31, and an alignment light source can be provided in the optical path branched from the optical path of the imaging optical system 30 by the dichroic filter.

  The fundus camera unit 2 is provided with a focus optical system 60 as in a conventional fundus camera. The focus optical system 60 generates an index (split index) for focusing on the fundus oculi Ef. When performing the focus adjustment, the reflecting surface of the reflecting rod 67 is obliquely provided on the optical path of the illumination optical system 10. The light (focus light) output from the LED 61 of the focus optical system 60 passes through the relay lens 62, is separated into two light beams by the split indicator plate 63, passes through the two-hole aperture 64, and is reflected by the mirror 65, The light is focused on the reflecting surface of the reflecting bar 67 by the condenser lens 66 and reflected. Further, the focus light passes through the relay lens 20, passes through the ring-shaped opening (23 t) of the corneal diaphragm 23 c, is reflected by the perforated mirror 21, passes through the dichroic mirror 46, and is refracted by the objective lens 22 to be retinal fundus. Projected to Ef.

  The fundus reflection light of the focus light is detected by the CCD image sensor 35 through the same path as the return light of the illumination light projected on the fundus oculi Ef. A light reception image (split index) by the CCD image sensor 35 is displayed on the display device 3 together with the observation image. The arithmetic control unit 200 analyzes the position of the split index and moves the focusing lens 31 and the focus optical system 60 to perform focusing as in the conventional case (autofocus function). Alternatively, focusing may be performed manually while visually checking the split indicator.

  The dichroic mirror 46 branches the optical path for OCT measurement from the optical path for fundus imaging. The dichroic mirror 46 reflects the light in the wavelength band used for the OCT measurement and the light in the wavelength band used for the alignment light flux, and transmits the fundus photographing light. In this optical path for OCT measurement, a collimator lens unit 40, an optical path length changing unit 41, a galvano scanner 42, a focusing lens 43, a mirror 44, and a relay lens 45 are provided in this order from the OCT unit 100 side. It has been.

  The optical path length changing unit 41 is movable in the direction of the arrow shown in FIG. 1 and changes the optical path length of the optical path for OCT measurement. This change in the optical path length is used for correcting the optical path length according to the axial length of the eye E or adjusting the interference state. The optical path length changing unit 41 includes, for example, a corner cube and a mechanism for moving the corner cube.

  The galvano scanner 42 changes the traveling direction of light (signal light LS) passing through the optical path for OCT measurement. Thereby, the fundus oculi Ef can be scanned with the signal light LS. The galvano scanner 42 includes, for example, a galvanometer mirror that scans the signal light LS in the x direction, a galvanometer mirror that scans in the y direction, and a mechanism that drives these independently. Thereby, the signal light LS can be scanned in an arbitrary direction on the xy plane.

  The fundus camera unit 2 is provided with an anterior eye camera 300. The anterior eye camera 300 images the anterior eye part Ea from different directions. In this embodiment, two cameras are provided on the surface of the fundus camera unit 2 on the subject side (see anterior eye cameras 300A and 300B shown in FIG. 5A). Further, as shown in FIGS. 1 and 5A, the anterior eye cameras 300A and 300B are provided at positions deviated from both the optical path of the illumination optical system 10 and the optical path of the photographing optical system 30, respectively. Hereinafter, the two anterior eye cameras 300 </ b> A and 300 </ b> B may be collectively represented by reference numeral 300.

  In this embodiment, two anterior eye cameras 300A and 300B are provided, but the number of anterior eye cameras in the present invention is an arbitrary number of 2 or more. In consideration of the arithmetic processing described later, a configuration that can photograph the anterior segment from two different directions is sufficient.

  In this embodiment, the anterior segment camera 300 is provided separately from the illumination optical system 10 and the imaging optical system 30, but at least the imaging optical system 30 can be used to perform similar anterior segment imaging. . In other words, one of the two or more anterior segment cameras may include the photographing optical system 30. Anyway, this embodiment should just be comprised so that imaging | photography of the anterior eye part Ea is possible from two different (or more) directions.

  A configuration for illuminating the anterior segment Ea may be provided. This configuration includes, for example, one or more light sources. Typically, at least one light source (such as an infrared light source) can be provided in the vicinity of each of the two or more anterior segment cameras. In this embodiment, for example, a light source provided near the upper part of the anterior eye camera 300A and a light source provided near the lower part, and a light source provided near the upper part of the anterior eye camera 300B and provided near the lower part. And a light source.

  Two or more anterior segment cameras can photograph the anterior segment Ea substantially simultaneously from two or more different directions. “Substantially simultaneously” indicates that, for example, in photographing with two or more anterior segment cameras, a deviation in photographing timing that allows negligible eye movement is allowed. Thereby, an image when the eye E is substantially at the same position (orientation) can be acquired by two or more anterior segment cameras.

  Further, the shooting by two or more anterior segment cameras may be moving image shooting or still image shooting. In the case of moving image shooting, substantially simultaneous anterior ocular shooting as described above can be realized by controlling the shooting start timing to match or controlling the frame rate and shooting timing of each frame. . On the other hand, in the case of still image shooting, this can be realized by controlling to match the shooting timing.

<OCT unit 100>
An example of the configuration of the OCT unit 100 will be described with reference to FIG. The OCT unit 100 is provided with an optical system for acquiring an OCT image of the fundus oculi Ef. This optical system has the same configuration as a conventional spectral domain type optical coherence tomography. That is, this optical system divides the low-coherence light into reference light and signal light, projects the signal light onto the fundus oculi Ef, and returns the return light of the signal light projected onto the fundus oculi Ef and the reference light via the reference light path. Interference light is generated by causing interference, and the interference light is dispersed to detect the spectral component. A detection result (detection signal) by the optical system is sent to the arithmetic control unit 200.

  In the case of a swept source type optical coherence tomography, a wavelength swept light source is provided instead of a light source that outputs a low-coherence light source, and a photodetector such as a balanced photodiode is provided instead of a spectroscope. It is done. In general, for the configuration of the OCT unit 100, a known technique corresponding to the type of OCT can be arbitrarily applied.

  The light source unit 101 outputs a broadband low-coherence light L0. The low coherence light L0 includes, for example, a near-infrared wavelength band (about 800 nm to 900 nm) and has a temporal coherence length of about several tens of micrometers. Note that near-infrared light having a wavelength band that cannot be visually recognized by the human eye, for example, a center wavelength of about 1040 to 1060 nm, may be used as the low-coherence light L0.

  The light source unit 101 includes a light output device such as a super luminescent diode (SLD), an LED, or an SOA (Semiconductor Optical Amplifier).

  The low-coherence light L0 output from the light source unit 101 is guided to the fiber coupler 103 by the optical fiber 102 and split into the signal light LS and the reference light LR.

  The reference light LR is guided by the optical fiber 104 and reaches the optical attenuator (attenuator) 105. The optical attenuator 105 automatically adjusts the amount of the reference light LR guided to the optical fiber 104 under the control of the arithmetic control unit 200 using a known technique. The reference light LR whose light amount has been adjusted by the optical attenuator 105 is guided by the optical fiber 104 and reaches the polarization adjuster (polarization controller) 106. For example, the polarization adjuster 106 is a device that adjusts the polarization state of the reference light LR guided in the optical fiber 104 by applying external stress to the looped optical fiber 104. The configuration of the polarization adjuster 106 is not limited to this, and any known technique can be used. The reference light LR whose polarization state is adjusted by the polarization adjuster 106 reaches the fiber coupler 109.

  The signal light LS generated by the fiber coupler 103 is guided by the optical fiber 107 and converted into a parallel light beam by the collimator lens unit 40. Further, the signal light LS reaches the dichroic mirror 46 via the optical path length changing unit 41, the galvano scanner 42, the focusing lens 43, the mirror 44, the relay lens 45, and the dichroic filter 52. The signal light LS is reflected by the dichroic mirror 46, refracted by the objective lens 22, and projected onto the fundus oculi Ef. The signal light LS is scattered and reflected at various depth positions of the fundus oculi Ef. The backscattered light (return light) of the signal light LS from the fundus oculi Ef travels in the same direction as the forward path in the reverse direction, is guided to the fiber coupler 103, and reaches the fiber coupler 109 via the optical fiber.

  The fiber coupler 109 causes the backscattered light of the signal light LS to interfere with the reference light LR that has passed through the optical fiber 104. The interference light LC generated thereby is guided by the optical fiber 110 and emitted from the emission end 111. Further, the interference light LC is converted into a parallel light beam by the collimator lens 112, spectrally resolved by the diffraction grating 113, condensed by the condenser lens 114, and projected onto the light receiving surface of the photodetector 115. Although the diffraction grating 113 shown in FIG. 3 is a transmission type, other types of spectroscopic elements such as a reflection type diffraction grating can also be used.

  The photodetector 115 is, for example, a line sensor, and detects a plurality of spectral components of the split interference light LC and converts each of them into electric charges. The photodetector 115 accumulates electric charges to generate a detection signal, and sends it to the arithmetic control unit 200.

  In this embodiment, a Michelson interferometer is used, but any type of interferometer such as a Mach-Zehnder type can be appropriately used. Further, instead of the CCD image sensor, another form of image sensor such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor can be used.

<Calculation control unit 200>
The configuration of the arithmetic control unit 200 will be described. The arithmetic control unit 200 analyzes the detection signal input from the photodetector 115 and forms an OCT image of the fundus oculi Ef. The calculation process for this is the same as that of a conventional spectral domain type optical coherence tomography.

  The arithmetic control unit 200 controls each part of the fundus camera unit 2, the display device 3, and the OCT unit 100. For example, the arithmetic control unit 200 displays an OCT image of the fundus oculi Ef on the display device 3.

  As the control of the fundus camera unit 2, the arithmetic control unit 200 controls the operation of the observation light source 11, the imaging light source 15, the alignment light source 51, and the LED 61, the operation control of the LCD 39, and the focusing lenses 31 and 43. Movement control, movement control of the reflecting rod 67, movement control of the focus optical system 60, movement control of the optical path length changing unit 41, operation control of the galvano scanner 42, operation control of the anterior eye camera 300, and the like are performed. . When a light source for illuminating the anterior segment (anterior segment illumination light source: described above) is provided, the arithmetic control unit 200 controls the operation of the anterior segment illumination light source.

  As control of the OCT unit 100, the arithmetic control unit 200 controls the operation of the light source unit 101, the operation control of the optical attenuator 105, the operation control of the polarization adjuster 106, the operation control of the photodetector 115, and the like. I do.

  The arithmetic control unit 200 includes, for example, a processor, a RAM, a ROM, a hard disk drive, a communication interface, etc., as in a conventional computer. A computer program for controlling the ophthalmologic apparatus 1 is stored in a storage device such as a hard disk drive. The arithmetic control unit 200 may include various circuits, for example, a circuit for forming an OCT image. The arithmetic control unit 200 may include an operation device (input device) such as a keyboard and a mouse, and a display device such as an LCD.

  The fundus camera unit 2, the display device 3, the OCT unit 100, and the calculation control unit 200 may be configured integrally (that is, in a single housing) or separated into two or more housings. It may be.

<Control system>
The configuration of the control system of the ophthalmologic apparatus 1 will be described with reference to FIGS. 4A and 4B.

<Control unit 210>
The control system of the ophthalmologic apparatus 1 is configured around the control unit 210. The control unit 210 includes, for example, a processor, a RAM, a ROM, a hard disk drive, a communication interface, and the like. The control unit 210 includes a main control unit 211, a storage unit 212, and an optical system position acquisition unit 213.

<Main control unit 211>
The main control unit 211 performs the various operation controls described above. In the movement control of the focusing lens 31, the main control unit 211 controls a focusing driving unit (not shown) to move the focusing lens 31 in the optical axis direction. Thereby, the focus position of the photographic optical system 30 is changed. Similarly, in the movement control of the focusing lens 43, the main control unit 211 controls a focusing driving unit (not shown) to move the focusing lens 43 in the optical axis direction. Thereby, the focus position of the optical system that forms the optical path of the signal light is changed.

  The main control unit 211 can move the optical system provided in the fundus camera unit 2 three-dimensionally by controlling the optical system driving unit 2A. This control is executed in auto alignment and tracking. Tracking is a function that maintains a suitable positional relationship in alignment (and focus) by causing the position of the apparatus optical system to follow the eye movement.

  In this embodiment, the anterior eye camera 300 is provided in the housing of the fundus camera unit 2. Therefore, the main control unit 211 can move the anterior eye camera 300 by controlling the optical system driving unit 2A. Further, it is possible to provide a photographing moving unit that can independently move two or more anterior eye camera 300. For example, the imaging movement unit may include a driving mechanism (an actuator, a power transmission mechanism, etc.) provided for each anterior eye camera 300. Alternatively, the photographing moving unit is configured to move two or more anterior eye cameras 300 by transmitting power generated by a single actuator by a power transmission mechanism provided for each anterior eye camera 300. May be.

  The main control unit 211 performs a process of writing data to the storage unit 212 and a process of reading data from the storage unit 212. The main control unit 211 also controls the user interface 240.

<Storage unit 212>
The storage unit 212 stores various data. Examples of the data stored in the storage unit 212 include image data of an OCT image, image data of a fundus image, and eye information to be examined. The eye information includes information about the subject such as patient ID and name, and information about the eye such as left / right eye identification information. The storage unit 212 stores a computer program and data for operating the ophthalmologic apparatus 1.

  In the storage unit 212, aberration information (not shown) is stored in advance. In the aberration information, information on distortion aberration generated in the captured image due to the influence of the optical system mounted on each anterior segment camera 300 is recorded. Here, the optical system mounted on the anterior segment camera 300 includes an optical element that generates distortion, such as a lens. The aberration information can be said to be a parameter obtained by quantifying the distortion that these optical elements give to the photographed image.

  An example of a method for generating aberration information will be described. Taking the instrumental difference (difference in distortion) of the anterior segment camera 300 into consideration, the following measurement is performed for each anterior segment camera 300. The operator prepares a predetermined reference point. The reference point is an imaging target used for detecting distortion. The operator performs multiple shootings while changing the relative position between the reference point and the anterior eye camera 300. Thereby, a plurality of captured images of the reference point captured from different directions are obtained. The operator generates aberration information of the anterior eye camera 300 by analyzing a plurality of acquired captured images with a computer. The computer that performs the analysis processing may be the data processing unit 230 or any other computer (such as an inspection computer or a maintenance computer before product shipment).

The analysis process for generating aberration information includes, for example, the following steps:
An extraction step of extracting an image region corresponding to the reference point from each captured image;
A distribution state calculation step of calculating a distribution state (coordinates) of an image area corresponding to a reference point in each captured image;
A distortion aberration calculating step of calculating a parameter representing distortion based on the obtained distribution state;
A correction coefficient calculation step of calculating a coefficient for correcting distortion based on the obtained parameter.

  Parameters relating to distortion aberration given to an image by the optical system include principal point distance, principal point position (vertical direction, horizontal direction), lens distortion (radiation direction, tangential direction), and the like. The aberration information is configured as information (for example, table information) in which the identification information of each anterior eye camera 300 is associated with the correction coefficient corresponding thereto. The aberration information generated in this way is stored in the storage unit 212 by the main control unit 211. Such generation of aberration information and aberration correction based on the aberration information are referred to as camera calibration.

<Optical system position acquisition unit 213>
The optical system position acquisition unit 213 acquires the current position of the data acquisition optical system mounted on the ophthalmologic apparatus 1. The data acquisition optical system is an optical system for optically acquiring data of the eye E. The data acquisition optical system of the ophthalmologic apparatus 1 (combined machine of fundus camera and optical coherence tomography) includes a configuration for acquiring an image of the eye E (fundus Ef, anterior segment Ea, etc.).

  For example, the optical system position acquisition unit 213 receives information representing the content of movement control of the optical system drive unit 2A from the main control unit 211, and acquires the current position of the data acquisition optical system. A specific example of this process will be described. The main control unit 211 controls the optical system driving unit 2A at a predetermined timing (when the apparatus is activated, when patient information is input, etc.) to move the data acquisition optical system to a predetermined initial position. Thereafter, each time the optical system driving unit 2A is controlled, the main control unit 211 records the control contents. Thereby, a history of control contents is obtained. The optical system position acquisition unit 213 acquires the control content up to the present with reference to this history, and obtains the current position of the data acquisition optical system based on the control content.

  Further, whenever the main control unit 211 controls the optical system driving unit 2A, the control content is transmitted to the optical system position acquisition unit 213, and each time the optical system position acquisition unit 213 receives the control content, the data acquisition optical system. The current position may be obtained sequentially.

  In another example, the optical system position acquisition unit 213 includes a position sensor that detects the position of the data acquisition optical system.

  The main control unit 211 can control the optical system driving unit 2A based on the current position acquired by the optical system position acquisition unit 213 and the movement target position determined by the data processing unit 230. Thereby, the data acquisition optical system can be moved to the movement target position. Specifically, the main control unit 211 obtains a difference between the current position and the movement target position. This difference value is, for example, a vector value having a current position as a start point and a movement target position as an end point. This vector value is, for example, a three-dimensional vector value expressed in an xyz coordinate system.

<Image forming unit 220>
The image forming unit 220 forms tomographic image data of the fundus oculi Ef based on the detection signal from the photodetector 115. This process includes processes such as noise removal (noise reduction), filter processing, and FFT (Fast Fourier Transform) as in the conventional spectral domain type optical coherence tomography. In the case of another type of optical coherence tomography, the image forming unit 220 executes a known process corresponding to the type.

  The image forming unit 220 includes a processor. The “image data” and the “image” based on the “image data” may be identified.

<Data processing unit 230>
The data processing unit 230 performs image processing and analysis processing on the image formed by the image forming unit 220. For example, the data processing unit 230 executes correction processing such as luminance correction and dispersion correction. Further, the data processing unit 230 performs image processing and analysis processing on images (fundus image, anterior eye image, etc.) obtained by the fundus camera unit 2. Further, the data processing unit 230 performs image processing and analysis processing on the image acquired by the anterior eye camera 300. The data processing unit 230 includes a processor.

  The data processing unit 230 acquires a first alignment information for performing alignment with the cornea as a reference (corneal alignment function) and a function for acquiring second alignment information for performing alignment with the pupil as a reference (pupil alignment). Function) and a function (position determination function) for determining a movement target position of the data acquisition optical system based on the first alignment information and the second alignment information.

  In order to implement these functions, the exemplary data processing unit 230 includes the following elements. The configuration for realizing the corneal alignment function includes at least a Purkinje image specifying unit 2321 and a first position calculation unit 2322, and may optionally include an image correction unit 231. Elements for realizing the pupil alignment function include at least a pupil center specifying unit 2331 and a second position calculation unit 2332, and may optionally include an image correction unit 231. The configuration for realizing the position determination function includes a movement target position determination unit 235. The movement target position is a position representing the movement destination of the data acquisition optical system in alignment.

  Further, the data processing unit 230 has a function for acquiring information indicating the size of the pupil of the eye E. A configuration for realizing this function includes at least a pupil size calculation unit 234 and may optionally include an image correction unit 231. The size of the pupil (pupil size) includes, for example, any of a pupil diameter, a pupil area, and a pupil circumference. The movement target position determination unit 235 can determine the movement target position based on the pupil size calculated by the pupil size calculation unit 234. Further, the movement target position determination unit 235 can determine the movement target position based on the fixation state of the eye E.

<Image Correction Unit 231>
The image correction unit 231 corrects the distortion of the captured image obtained by the anterior eye camera 300 based on the aberration information stored in the storage unit 212. This process is executed by, for example, a known image processing technique based on a correction coefficient for correcting distortion. Note that the aberration information and image correction unit 231 may not be provided when the distortion aberration given to the captured image by the optical system of the anterior segment camera 300 is sufficiently small.

  The captured image corrected by the image correcting unit 231 is sent to at least one of the Purkinje image specifying unit 2321, the pupil center specifying unit 2331, and the pupil size calculating unit 234. For example, the main control unit 211 can switch the transmission destination of the captured image corrected by the image correction unit 231 according to the operation mode and the processing phase.

<Purkinje image identification part 2321>
The main control unit 211 turns on the alignment light source 51 of the light beam projection optical system 50. Thereby, the alignment light beam is projected onto the anterior eye portion Ea, and a Purkinje image is formed. The Purkinje image is formed at a position displaced in the axial direction (z direction) from the apex of the cornea by a distance that is a half of the radius of curvature of the cornea. In a standard living eye, the corneal curvature is about 7.8 to 8.0 millimeters, and the Purkinje image is formed at a position displaced about 3.9 to 4.0 millimeters from the apex of the cornea to the retinal side. Thus, the position of the Purkinje image is a typical example of the position with reference to the cornea.

  The anterior segment Ea on which the alignment light flux is projected is photographed substantially simultaneously by the two anterior segment cameras 300. Two captured images acquired substantially simultaneously by the two anterior eye cameras 300 are corrected by the image correction unit 231 as necessary, and input to the Purkinje image specifying unit 2321.

  The Purkinje image specifying unit 2321 specifies a Purkinje image (an image region corresponding to the Purkinje image) by analyzing each of the two captured images. This specifying process includes, for example, a threshold process related to a pixel value for searching for a bright spot (high luminance pixel) corresponding to the Purkinje image, as in the conventional case. Thereby, an image region in the captured image corresponding to the Purkinje image is specified.

  The Purkinje image specifying unit 2321 can obtain the position of the representative point in the image area corresponding to the Purkinje image. The representative point may be, for example, the center point or barycentric point of the image area. In this case, for example, the Purkinje image specifying unit 2321 can obtain an approximate circle or approximate ellipse around the periphery of the image region, and can determine the center or center of gravity of the approximate circle or approximate ellipse.

  The processing result acquired by the Purkinje image specifying unit 2321 is input to the first position calculating unit 2322.

<First position calculation unit 2322>
The first position calculation unit 2322 obtains a position (first position) with reference to the cornea based on the information input from the Purkinje image specifying unit 2321. The first position represents the position of the Purkinje image specified by the Purkinje image specifying unit 2321. The first position may include at least a position in the x direction (x coordinate value) and a position in the y direction (y coordinate value), and may further include a position in the z direction (z coordinate value).

  As described above, the Purkinje image specifying unit 2321 specifies a Purkinje image from each of two captured images acquired substantially simultaneously. FIG. 6 shows an outline of two exemplary captured images (anterior eye image). The captured image 400A is an anterior segment image acquired by the anterior segment camera 300A, and the captured image 400B is an anterior segment image acquired by the anterior segment camera 300B. Here, the captured images 400 </ b> A and 400 </ b> B may be anterior segment images corrected by the image correcting unit 231.

  The photographed image 400A is an image obtained by photographing the anterior segment Ea from an oblique direction. In the captured image 400A, a pupil region 401A and a Purkinje image 402A are depicted. The Purkinje image specifying unit 2321 specifies the Purkinje image 402A in the captured image 400A.

  Similarly, the captured image 400B is an image obtained by capturing the anterior segment Ea from an oblique direction different from that of the captured image 400A. In the photographed image 400B, a pupil region 401B and a Purkinje image 402B are depicted. The Purkinje image specifying unit 2321 specifies the Purkinje image 402B in the captured image 400B.

  The captured images 400A and 400B are images acquired by capturing from a direction different from the optical axis of the objective lens 22. Further, when the xy alignment is substantially matched, Purkinje images 402A and 402B are formed on the optical axis of the objective lens 22, as shown in FIG.

  Since the expected angles (angles with respect to the optical axis of the objective lens 22) of the anterior eye cameras 300A and 300B are known and the photographing magnification is also known, the position of the Purkinje image 402A in the photographed image 400A and the Purkinje in the photographed image 400B. Based on the position of the image 402B, the relative position (three-dimensional position in real space) of the Purkinje image formed on the anterior segment Ea with respect to the ophthalmologic apparatus 1 (anterior segment cameras 300A and 300B) can be obtained.

  Further, based on the relative position (deviation amount) between the pupil region 401A and the Purkinje image 402A in the photographed image 400A and the relative position (deviation amount) between the pupil region 401B and the Purkinje image 402B in the photographed image 400B. The relative position between the pupil of the optometry E and the Purkinje image formed on the anterior segment Ea can be obtained.

  The calculation of the relative position exemplified above can be performed on the same principle as the calculation of the pupil center position (described later), for example.

  The processing result (first position, first alignment information) acquired by the first position calculation unit 2322 is input to the movement target position determination unit 235.

<Pupil center identification unit 2331>
The pupil center specifying unit 2331 specifies each position in the captured image corresponding to a predetermined feature point of the anterior segment Ea by analyzing each captured image (with the distortion corrected by the image correcting unit 231). . In this embodiment, the pupil center of the eye E is specified. Note that the center of gravity of the pupil may be obtained as the pupil center. Moreover, it can also be configured to specify feature points other than the pupil center (pupil centroid).

  First, the pupil center specifying unit 2331 specifies an image region (pupil region) corresponding to the pupil of the eye E based on the distribution of pixel values (such as luminance values) of the captured image. In general, since the pupil is expressed with lower luminance than other parts, the pupil region can be specified by searching for a low luminance image region. At this time, the pupil region may be specified in consideration of the shape of the pupil. That is, the pupil region can be specified by searching for a substantially circular and low luminance image region.

  Next, the pupil center specifying unit 2331 specifies the center position of the specified pupil region. Since the pupil is substantially circular as described above, the contour of the pupil region can be specified, the center position of the approximate ellipse of this contour can be specified, and this can be used as the pupil center. Further, the center of gravity of the pupil region may be obtained, and the center of gravity position may be used as the center of the pupil.

  Even when other feature points are applied, the position of the feature points can be specified based on the distribution of pixel values of the captured image as described above.

<Second position calculation unit 2332>
The second position calculation unit 2332 determines the pupil based on the positions (and photographing magnifications) of the two anterior eye cameras 300 and the positions of the pupil centers in the two captured images specified by the pupil center specifying unit 2331. A reference position (second position) is obtained. The second position is, for example, a three-dimensional position of the pupil center of the eye E. Processing for obtaining the second position will be described with reference to FIGS. 7A and 7B.

  FIG. 7A is a top view showing the positional relationship between the eye E and the anterior eye cameras 300A and 300B. FIG. 7B is a side view showing the positional relationship between the eye E and the anterior eye cameras 300A and 300B. The distance (baseline length) between the two anterior eye cameras 300A and 300B is represented by “B”. A distance (imaging distance) between the baselines of the two anterior eye cameras 300A and 300B and the pupil center P of the eye E is represented by “H”. A distance (screen distance) between each anterior eye camera 300A and 300B and its screen plane is represented by “f”.

  In such an arrangement state, the resolution of the image captured by the anterior eye cameras 300A and 300B is expressed by the following equation. Here, Δp represents pixel resolution.

Resolution in xy direction (planar resolution): Δxy = H × Δp / f
Resolution in the z direction (depth resolution): Δz = H × H × Δp / (B × f)

  The second position calculation unit 2332 is illustrated in FIGS. 7A and 7B with respect to the positions (known) of the two anterior eye cameras 300A and 300B and the position corresponding to the pupil center P in the two captured images. The three-dimensional position of the pupil center P is calculated by applying a known trigonometric method considering the arrangement relationship.

  The processing result (second position and second alignment information) acquired by the second position calculation unit 2332 is input to the movement target position determination unit 235.

<Pupil size calculator 234>
The pupil size calculation unit 234 acquires information representing the pupil size of the eye E. For example, the pupil size calculation unit 234 calculates the pupil size based on an image acquired by photographing the anterior segment Ea of the eye E. Therefore, the pupil size calculation unit 234 is acquired by the anterior ocular segment image acquired by the illumination optical system 10 and the imaging optical system 30, the anterior ocular segment image acquired by the anterior ocular camera 300, and other ophthalmologic apparatuses. At least one of the obtained anterior segment images can be analyzed.

  The pupil size calculation unit 234 executes, for example, processing for specifying a pupil region and processing for specifying a peripheral edge (contour) of the pupil region in the same manner as the pupil center specifying unit 2331. The pupil size calculation unit 234 may execute processing for approximating the periphery of the pupil region with a closed curve (circle, ellipse, etc.).

  In a typical example, the pupil size calculation unit 234 can execute processing for calculating the periphery of the pupil region or the diameter of the approximate closed curve thereof. This diameter may be, for example, the diameter of an approximate circle, or the major axis and / or minor axis of an approximate ellipse. Alternatively, the diameter may be a maximum value, a minimum value, an average value, a median value, or the like of a plurality of diameters calculated for the approximate closed curve.

  In another example, the pupil size calculation unit 234 can execute processing for calculating the area of the pupil region. Or the pupil size calculation part 234 can perform the process which calculates the area of the area | region enclosed by the approximate closed curve of the periphery of a pupil area | region.

  The processing executed by the pupil size calculation unit 234 is not limited to the processing illustrated here. For example, as shown in FIGS. 7A and 7B and the like, when the anterior eye cameras 300A and 300B look at the anterior eye part Ea from an oblique direction, the pupil size calculation unit 234 determines the imaging magnification and expectation of the anterior eye cameras 300A and 300B. Based on the angle, the value of the diameter and the value of the area can be corrected. Moreover, when the measurement result of the pupil size of the eye E is stored in a medical database such as an electronic medical record system, the ophthalmologic apparatus 1 can acquire the pupil size of the eye E from this medical database.

  The processing result (pupil size information) acquired by the pupil size calculation unit 234 is input to the movement target position determination unit 235.

<Movement target position determination unit 235>
The movement target position determination unit 235 determines the movement target position of the data acquisition optical system based on the processing result acquired by the first position calculation unit 2322 and the processing result acquired by the second position calculation unit 2332. .

  The processing result acquired by the first position calculation unit 2322 is, for example, first alignment information including the position (first position) of the eye E measured with reference to the cornea, or information obtained from the first position. May be included in the first alignment information. Examples of information obtained from the first position include a relative position between the current position and the first position of the data acquisition optical system and a relative position of the first position with respect to an arbitrary position.

  The processing result acquired by the second position calculation unit 2332 is, for example, second alignment information including the position (second position) of the eye E measured with reference to the pupil, or information obtained from the second position. May be included in the second alignment information. Examples of information obtained from the second position include a relative position between the current position and the second position of the data acquisition optical system and a relative position of the second position with respect to an arbitrary position.

  In one example, the movement target position determination unit 235 may be configured to determine a movement target position based on the first alignment information and the second alignment information when a predetermined condition is satisfied. In other words, conditions that serve as a trigger for determining the movement target position based on the first alignment information and the second alignment information can be set in advance.

  For example, the movement target position determination unit 235 is configured to execute a process of comparing the first alignment information and the second alignment information and a process of determining whether or not the comparison result satisfies a predetermined condition. . When it is determined that the comparison result satisfies the predetermined condition, the movement target position determination unit 235 is configured to determine the movement target position based on the first alignment information and the second alignment information.

  The first alignment information includes a first position (Purkinje image position) acquired with reference to the cornea, and the second alignment information includes a second position (position of the pupil center) acquired with reference to the pupil. In the case where it is included, as a process of comparing the first alignment information and the second alignment information, the movement target position determination unit 235 can calculate the difference between the first position and the second position.

  This difference process may include a process of calculating a difference between the first position and the second position in the x direction and a process of calculating a difference between the first position and the second position in the y direction. The process of calculating the difference between the first position and the second position in the x direction includes, for example, a process of subtracting the x coordinate value of the second position from the x coordinate value of the first position, and a process of calculating the difference between the x coordinate value of the second position. A process of subtracting the x-coordinate value at one position, and the difference between the x-coordinate value at the first position with respect to a predetermined x-coordinate value (reference x-coordinate value) and the difference between the x-coordinate values at the second position with respect to the reference x-coordinate value; May include any of the processes for obtaining. The process for calculating the difference between the first position and the second position in the y direction may be the same.

  When both the first position and the second position include a position in the z direction (z coordinate value), this difference process may include a process of calculating a difference between the first position and the second position in the z direction. The process of calculating the difference between the first position and the second position in the z direction may be performed in the same manner as the process of calculating the difference between the first position and the second position in the x direction.

  After the process of comparing the first alignment information and the second alignment information, the movement target position determination unit 235 can execute a process of determining whether or not the comparison result satisfies a predetermined condition. When the difference between the first position and the second position is calculated, the movement target position determination unit 235 compares the calculated difference with a predetermined threshold value. The threshold may be set clinically and / or theoretically, for example.

  The difference compared to the threshold may be any one of a one-dimensional difference between the first position and the second position, a two-dimensional difference, and a three-dimensional difference. The one-dimensional difference may be any of a difference in the x direction, a difference in the y direction, a difference in the z direction, and a difference in an arbitrary direction. The two-dimensional difference may be any of a difference on the xy plane, a difference on the yz plane, a difference on the zx plane, and a difference on an arbitrary plane. A three-dimensional difference is a difference defined by the xyz coordinate system.

The threshold value of the difference (absolute value) in the x direction is d _x (d _x > 0), and the threshold value of the difference (absolute value) in the y direction is _dy (d _y > 0). Here, it may be equal to the d _x and d _y, may not be equal. The unit of the threshold _values d _x and dy is, for example, millimeter.

In one example of when comparing 1-dimensional differences in the x-direction, the movement target position determination unit 235, the difference between the x-coordinate values U _x and x coordinate value V _x of the second position V of the first position U Δ _x = abs (U _x −V _x ) is calculated. Furthermore, the movement target position determination unit 235 compares the calculated difference Δ _x with the threshold value d _x . At this time, the movement target position determination unit 235 may be configured to determine whether the difference Δ _x and the threshold value d _x satisfy the condition “Δ _x > d _x ”. Similar processing can also be performed when comparing one-dimensional differences in arbitrary directions within the xy plane.

In one example when comparing two-dimensional differences on the xy plane, the movement target position determination unit 235 includes the x coordinate value U _x and the y coordinate value U _{y of} the first position U and the x of the second position V. based on the coordinate values _{V x} and y-coordinate value _{V y,} the distance _{D xy} = √ between the first position U and the second position V in the xy plane _{[(U x -V x) ^} 2 + (U y - V _y ) ^ 2] is calculated. Further, the movement target position determination unit 235 compares the calculated distance D _xy with a predetermined threshold value d _xy . At this time, the movement target position determination unit 235 may be configured to determine whether the distance D _xy and the threshold value d _xy satisfy the condition “D _xy > d _xy ”.

The threshold value of the difference (absolute value) in the z direction is defined as d _z (d _z > 0). In one example, as described above, the anterior chamber depth of a standard living eye is about 3.0 millimeters, and the standard living eye is positioned about 4.0 millimeters from the corneal apex to the retina side. Considering the formation of a Purkinje image, the difference threshold in the z direction can be expressed as d _z = 1 ± ε (for example, 0 <ε <1). Here, “1” in the first term on the right side represents the difference between the position where the Purkinje image is formed and the corneal-pupil distance approximated by the anterior chamber depth. Units of this threshold d _z is in millimeters.

In one example of when comparing 1-dimensional differences in the z-direction, the movement target position determination unit 235, the difference between the z-coordinate value V _z of the z-coordinate values U _z and the second position V of the first position U Δ _z = abs (U _z −V _z ) is calculated. Furthermore, the movement target position determination unit 235 compares the calculated difference delta _z and threshold d _z. In this case, the movement target position determination unit 235 may be configured such that the difference delta _z and the threshold value d _z to determine whether to satisfy the condition "delta _z> d _z".

In one example when comparing three-dimensional differences, the movement target position determination unit 235 includes a three-dimensional coordinate value (U _x , U _y , U _z ) of the first position U and 3 of the second position V. Based on the dimensional coordinate values (V _x , V _y , V _z ), the distance D _xyz = √ [(U between the first position U and the second position V in the three-dimensional space defined by the xyz coordinate system. _{x -V x) ^ 2 + (} U y -V y) ^ 2 + (U z -V z) ^ 2] is calculated. Furthermore, the movement target position determination unit 235 compares the calculated distance D _xyz with a predetermined threshold value d _xyz . At this time, the movement target position determination unit 235 may be configured to determine whether the distance D _xyz and the threshold value d _xyz satisfy the condition “D _xyz > d _xyz ”.

  When it is determined that the difference between the first position and the second position is greater than the threshold value, the movement target position determination unit 235 can determine the movement target position based on the first position and the second position. For example, the movement target position determination unit 235 can obtain a position between the first position and the second position, and can determine the movement target position based on this position.

  Typically, the movement target position can be set based on a position between the first position and the second position. In one example, the movement target position can be set based on an intermediate position between the first position and the second position (the midpoint of a line segment connecting the first position and the second position). In another example, the movement target position can be set based on a position displaced from the intermediate position toward the first position or the second position. For example, in consideration of reflection at the cornea, the movement target position can be set at a position displaced from the intermediate position to the first position side (corneal side).

  The ophthalmologic apparatus 1 can switch the alignment mode according to the pupil size of the eye E. In this embodiment, information indicating the pupil size of the eye E is provided by the pupil size calculator 234 or from a medical database.

  In one example, the movement target position determination unit 235 can determine whether the pupil size of the eye E is equal to or smaller than a predetermined threshold value. This process may be a determination of whether or not the eye E is a small pupil eye. For example, a clinically obtained threshold value is set in advance. When it is determined that the pupil size is equal to or smaller than the threshold, the movement target position determination unit 235 may determine the movement target position based on a position corresponding to the second alignment information (second position with reference to the pupil). it can. For example, when it is determined that the pupil size is equal to or smaller than the threshold value, the ophthalmologic apparatus 1 executes alignment in a mode based on the second alignment information.

  The movement target position determination unit 235 can switch the alignment mode according to the rotation state (fixation position) of the eye E. In this embodiment, the alignment mode is switched based on the presentation state of the fixation target. It is also possible to obtain the rotation state by analyzing the anterior segment image acquired by photographing the anterior segment Ea of the eye E.

  In one example, the main control unit 211 sends a predetermined control signal to the movement target position determination unit 235 when the LCD 39 is controlled to apply a fixation target for rotating the eye E to be rotated by a predetermined angle or more. The movement target position determination unit 235 that has received this control signal can determine the movement target position based on the position corresponding to the first alignment information (the position of the Purkinje image). For example, when a fixation target for rotating the subject eye E by a predetermined angle or more is applied, or when it is determined that the subject eye E is rotated by a predetermined angle or more based on the anterior segment image, ophthalmology The apparatus 1 performs alignment in a mode based on the first alignment information.

  The movement target position determined by the movement target position determination unit 235 is sent to the control unit 210. The control unit 210 controls the optical system driving unit 2A based on the movement target position.

  The data processing unit 230 includes, for example, a processor, a RAM, a ROM, a hard disk drive, and the like. A storage device such as a hard disk drive stores in advance a computer program that causes the processor to execute the above-described processing.

<User interface>
The user interface 240 includes a display unit 241 and an operation unit 242. The display unit 241 includes the display device of the arithmetic control unit 200 and the display device 3 described above. The operation unit 242 includes the operation device of the arithmetic control unit 200 described above. The operation unit 242 may include various buttons and keys provided on the housing of the ophthalmologic apparatus 1 or outside. For example, when the fundus camera unit 2 has a housing similar to that of a conventional fundus camera, the operation unit 242 may include a joystick or an operation panel provided on the housing. Further, the display unit 241 may include various display devices such as a touch panel provided in the housing of the fundus camera unit 2.

  The display unit 241 and the operation unit 242 do not need to be configured as individual devices. For example, a device in which a display function and an operation function are integrated, such as a touch panel, can be used. In that case, the operation unit 242 includes the touch panel and a computer program. The operation content for the operation unit 242 is input to the control unit 210 as an electrical signal. Further, operations and information input may be performed using the graphical user interface (GUI) displayed on the display unit 241 and the operation unit 242.

  At least a part of the user interface 240 may be provided outside the ophthalmologic apparatus 1. For example, in another embodiment, the ophthalmologic apparatus may be configured not to include a display device and to be able to transmit a signal to an external display device.

<Operation>
The operation of the ophthalmologic apparatus 1 will be described. An operation example of the ophthalmologic apparatus 1 is shown in FIGS. 8A and 8B. In addition, input of patient information (patient ID, patient name, etc.) of the subject, selection of examination type (examination mode), and the like are performed in advance.

(S1: Turn on the alignment light source)
The main control unit 211 turns on the alignment light source 51. Thereby, the alignment light beam is projected onto the anterior segment Ea.

(S2: Start photographing with the anterior segment camera)
The main control unit 211 starts imaging of the anterior segment Ea using the anterior segment cameras 300A and 300B. When the ophthalmologic apparatus 1 includes the anterior segment illumination light source, the main control unit 211 also performs control for turning on the anterior segment illumination light source.

  Each of the anterior eye cameras 300 </ b> A and 300 </ b> B repeats image acquisition at predetermined time intervals, and sequentially sends the acquired images to the control unit 210. The main control unit 211 sequentially sends a pair of anterior segment images acquired substantially simultaneously by the anterior segment cameras 300 </ b> A and 300 </ b> B to the data processing unit 230.

  The data processing unit 230 sequentially applies the following processing to a pair of anterior segment images that are sequentially input. Although optional, the image correction unit 231 can correct distortion of the anterior segment image based on the aberration information.

(S3: Purkinje image is detected)
The Purkinje image specifying unit 2321 analyzes the anterior ocular segment image (corrected for distortion) in order to specify the Purkinje image.

(S4: Was the Purkinje image detected successfully?)
When the Purkinje image is detected from the anterior segment image (for example, when the Purkinje image is detected from both of the pair of anterior segment images) (S4: Yes), the process proceeds to step S5. In this case, the Purkinje image specifying unit 2321 can obtain the position of the representative point in the image region corresponding to the Purkinje image.

  When the Purkinje image is not detected from the anterior segment image (for example, when the Purkinje image is not detected from at least one of the pair of anterior segment images) (S4: No), the process proceeds to step S10.

(S5: execute corneal alignment)
When a Purkinje image is detected from the anterior segment image in step S4 (S4: Yes), the first position calculation unit 2322 uses the detected Purkinje image as a reference for the position of the eye E (the first one) 1 position). In this example, the first position calculation unit 2322 calculates the three-dimensional position (x coordinate value, y coordinate value, z coordinate value) of the Purkinje image based on the pair of Purkinje images detected from the pair of anterior eye image. Can be sought.

  The main control unit 211 sets the optical axis of the objective lens 22 (the optical axis of the illumination optical system 10 and the imaging optical system) at a position corresponding to the x coordinate value and the y coordinate value of the Purkinje image obtained by the first position calculation unit 2322. The optical system driving unit 2A is controlled such that 30 optical axes and the optical axis of the optical system that guides the signal light LS are arranged. This corresponds to xy alignment with reference to the cornea.

  Furthermore, although it is optional, the main control unit 211 places the objective lens 22 (illumination optics) at a position away from the z coordinate value of the Purkinje image obtained by the first position calculation unit 2322 by a preset working distance. The optical system driving unit 2A can be controlled so that the system 10, the photographing optical system 30, and the optical system that guides the signal light LS) are arranged. This corresponds to z alignment with the cornea as a reference.

(S6: Was corneal alignment completed?)
Steps S3 to S6 are repeatedly executed until the cornea alignment in step S5 is completed. When the cornea alignment in step S5 is completed (when the optical axis of the objective lens 22 is arranged at a position corresponding to the x-coordinate value and the y-coordinate value of the Purkinje image) (S6: Yes), the process proceeds to step S20. .

(S10: detect pupil area)
If no Purkinje image is detected from the anterior segment image (S4: No), the pupil center specifying unit 2331 analyzes the anterior segment image (with distortion corrected) in order to detect the pupil region.

(S11: Has the pupil region been successfully detected?)
When the pupil region is detected from the anterior segment image (for example, when the pupil region is detected from both of the pair of anterior segment images) (S11: Yes), the process proceeds to step S12. In this case, the pupil center specifying unit 2331 can obtain a position (pixel) corresponding to the pupil center.

  When the pupil region is not detected from the anterior segment image (for example, when the pupil region is not detected from at least one of the pair of anterior segment images) (S11: No), the process proceeds to step S13.

(S12: Perform pupil alignment)
When the pupil region is detected from the anterior segment image (S11: Yes), the second position calculation unit 2332 determines the position of the eye E to be examined with reference to the pupil based on the detected pupil region (pupil center) ( 2nd position) is obtained. In this example, the second position calculation unit 2332 determines the three-dimensional position (x coordinate value, y coordinate value) of the pupil center based on a pair of pupil regions (a pair of pupil centers) detected from the pair of anterior segment images. , Z coordinate value).

  The main control unit 211 arranges the optical axis of the objective lens 22 at a position corresponding to the x-coordinate value and the y-coordinate value of the pupil center obtained by the second position calculation unit 2332, and the z-coordinate of the pupil center. The optical system driving unit 2A is controlled so that the objective lens 22 is arranged at a position away from the value by a preset working distance. This corresponds to xyz alignment with the pupil as a reference. When the pupil alignment is completed, the process returns to step S3.

(S13: Perform manual alignment)
When the pupil region is not detected from the anterior segment image (S11: No), the alignment mode is switched to the manual alignment mode. In the manual alignment mode, the main control unit 211 observes the anterior segment image acquired by the anterior segment camera 300A and / or 300B or the anterior segment Ea acquired by the observation optical system 10 and the imaging optical system 30. The image is displayed on the display unit 241 as a moving image in real time. The user operates the operation unit 242 to move the data acquisition optical system. At this time, the main control unit 211 controls the optical system driving unit 2 </ b> A according to the operation signal input from the operation unit 242. When manual alignment is completed, the process returns to step S3.

(S20: The position of the pupil is detected)
When the corneal alignment in step S5 is completed (S6: Yes), the pupil center specifying unit 2331 and the second position calculating unit 2332 analyze the pair of anterior eye images acquired after the completion of the corneal alignment, thereby obtaining the pupil center. Is obtained. At this time, the Purkinje image specifying unit 2321 and the first position calculating unit 2322 may obtain a three-dimensional position of the Purkinje image by analyzing a pair of anterior eye images acquired after completion of corneal alignment.

(S21: The relative position between the Purkinje image and the pupil is calculated)
The movement target position determination unit 235 obtains a relative position between the Purkinje image and the pupil center after completion of corneal alignment. The obtained relative position includes, for example, a relative position in the x direction (difference in x coordinate value), a relative position in the y direction (difference in y coordinate value), and a relative position in the z direction (difference in z coordinate value). .

(S22: Is the relative position within the allowable range?)
The movement target position determination unit 235 determines whether or not the relative position obtained in step S21 is included in a preset allowable range. In an exemplary embodiment, the allowable range may be defined using the threshold _values d _x , _dy , d _xy , d _{z, and the} like described above, and the determination process may be performed as described above.

  When it is determined that the relative position is included in the allowable range (S22: Yes), the process proceeds to step S23. When it is determined that the relative position is not included in the allowable range (S22: No), the process proceeds to step S30.

(S23: Execute focus adjustment etc.)
When it is determined that the relative position between the Purkinje image and the pupil center is included in the allowable range (S22: Yes), the main control unit 211 adjusts the focus of the imaging optical system 30 (adjusts the position of the focusing lens 31). ), Adjustment of predetermined conditions for fundus OCT and / or fundus imaging, such as focus adjustment of the optical system that guides the signal light LS (adjustment of the position of the focusing lens 43).

(S24: Execute fundus OCT)
The main control unit 211 performs an OCT scan of the fundus oculi Ef by controlling the OCT unit 100, the galvano scanner 42, and the like. Data collected thereby is sent to the image forming unit 220. The image forming unit 220 forms an OCT image of the fundus oculi Ef based on the collected data. The main control unit 211 can display the formed OCT image on the display unit 241 and / or store it in the storage unit 212.

(S25: Execute fundus imaging)
The main control unit 211 performs color photographing of the fundus oculi Ef by controlling the illumination optical system 10 and the photographing optical system 30. The main control unit 211 can display the acquired color fundus image on the display unit 241 and / or store the acquired color fundus image in the storage unit 212. This is the end of the processing related to this operation.

(S30: The movement target position is determined)
If it is determined in step S22 that the relative position between the Purkinje image and the pupil center is not included in the allowable range (S22: No), the data processing unit 230 performs a predetermined process for determining the movement target position. Run.

  In one example of the processing executed in step S30, the data processing unit 230 can refer to the pupil size of the eye E. For example, the pupil size calculation unit 234 analyzes the anterior ocular segment image (distortion corrected by the image correction unit 231) or the anterior ocular segment image acquired by the observation optical system 10 and the imaging optical system 30. Then, information indicating the pupil size of the eye E is obtained.

  The movement target position determination unit 235 determines whether the pupil size of the eye E is equal to or smaller than a predetermined threshold value. That is, the movement target position determination unit 235 determines whether or not the eye E is a small pupil eye.

  When it is determined that the eye E is a small pupil eye, the movement target position determination unit 235 can set the movement target position based on, for example, the second position with reference to the pupil. Here, the second position may be a position acquired in a step before step S30, or may be a position newly acquired in step S30. Further, the movement target position is, for example, a position corresponding to the same x coordinate value and y coordinate value as the second position, and is deviated by a predetermined distance from the second position in a direction opposite to the fundus oculi Ef (−z direction). It is the position that was placed. This predetermined distance is, for example, a distance corresponding to the sum of the cornea-pupil distance and the predetermined working distance.

  When it is determined that the eye E is not a small pupil eye, the movement target position determination unit 235, for example, a position (intermediate position) between a first position with reference to the cornea and a second position with reference to the pupil. The movement target position can be set based on the above. Here, the first position may be a position acquired in a step before step S30, or may be a position newly acquired in step S30. Similarly, the second position may be a position acquired in a step before step S30, or may be a position newly acquired in step S30. Further, the movement target position is, for example, a position corresponding to the same x coordinate value and y coordinate value as the intermediate position, and is displaced from the intermediate position by a predetermined distance in a direction opposite to the fundus oculi Ef (−z direction). Position. The predetermined distance is, for example, a distance corresponding to the sum of the distance between the intermediate position and the cornea and the working distance.

  In another example of the process executed in step S30, the data processing unit 230 can refer to the rotation state of the eye E. For example, the main control unit 211 sends information representing the fixation state of the eye E to the data processing unit 230.

  The information indicating the fixation state may be, for example, the above-described predetermined control signal, information indicating the control content of the LCD 39, information indicating the imaging region (imaging mode setting information or the like), and the like. The movement target position determination unit 235 determines whether or not the eye E is rotated by a predetermined angle or more based on information input from the main control unit 211.

  When it is determined that the eye E has been rotated by a predetermined angle or more, the movement target position determination unit 235 can set the movement target position based on, for example, the first position with reference to the cornea. Here, the first position may be a position acquired in a step before step S30, or may be a position newly acquired in step S30. The movement target position is, for example, a position corresponding to the same x-coordinate value and y-coordinate value as the first position, and a predetermined working distance from the first position in the direction opposite to the fundus oculi Ef (−z direction). It is a position that is only deviated.

  When it is determined that the eye E is not rotated by a predetermined angle or more, the movement target position determination unit 235, for example, a position between a first position with reference to the cornea and a second position with reference to the pupil ( The movement target position can be set based on the intermediate position. Here, the first position may be a position acquired in a step before step S30, or may be a position newly acquired in step S30. Similarly, the second position may be a position acquired in a step before step S30, or may be a position newly acquired in step S30. Further, the movement target position is, for example, a position corresponding to the same x coordinate value and y coordinate value as the intermediate position, and is displaced from the intermediate position by a predetermined distance in a direction opposite to the fundus oculi Ef (−z direction). Position. The predetermined distance is, for example, a distance corresponding to the sum of the distance between the intermediate position and the cornea and the working distance.

  Before being acquired by photographing the anterior eye portion Ea of the eye E instead of referring to the information indicating the fixation state of the eye E or in addition to referring to the information indicating the fixation state of the eye E An eye image can be referred to. In this case, the data processing unit 230 identifies the direction of the eye E (that is, the rotation angle of the eye E) by analyzing the anterior segment image. For example, a known gaze detection technique is applied to this process. The movement target position determination unit 235 can determine whether the rotation angle of the eye E is equal to or greater than a predetermined angle, and can set the movement target position according to the determination result.

  The movement target position determined in step S30 is sent to the control unit 210.

(S31: execute correction alignment)
The main control unit 211 controls the optical system driving unit 2A based on the movement target position determined in step S30 in order to correct the alignment state of the data acquisition optical system with respect to the eye E. Thereby, the data acquisition optical system is arranged at the movement target position determined in step S30.

  When such correction alignment is completed, the process proceeds to step S23. In step S23, focus adjustment or the like is executed. Next, in step S24, fundus OCT is executed. Subsequently, in step S25, fundus imaging is performed. The main control unit 211 can display an OCT image and / or a color fundus image on the display unit 241. Further, the main control unit 211 can store the OCT image and / or the color fundus image in the storage unit 212. This is the end of the processing related to this operation.

<Action and effect>
Several actions and effects of the ophthalmologic apparatus according to the embodiment will be described.

  The ophthalmologic apparatus according to the embodiment includes a data acquisition optical system, two or more imaging units, a first alignment unit, a second alignment unit, and a position determination unit.

  The data acquisition optical system has a configuration for acquiring data of the eye to be examined. In the ophthalmologic apparatus 1, the illumination optical system 10, the imaging optical system 30, the OCT optical system, and the like function as a data acquisition optical system.

  The illumination optical system 10 and the photographing optical system 30 have a configuration for performing digital photography of the fundus oculi Ef and the anterior segment Ea. Typically, the illumination optical system 10 includes a first diaphragm (corneal diaphragm 23c) corresponding to the cornea and a second diaphragm (crystal front diaphragm 23f, lens rear diaphragm 23r) corresponding to a predetermined intraocular region. . Here, the number of the second diaphragms is arbitrary, and may be one or two, for example. The photographing optical system 30 is configured to guide the return light of the illumination light projected onto the fundus oculi Ef by the illumination optical system 10 to the image sensor (CCD image sensors 35 and 38).

  The OCT optical system has a configuration for performing OCT of the fundus oculi Ef. Specifically, the OCT optical system includes an optical system that forms an optical path (signal optical path) of the signal light LS and an optical system that forms an optical path (reference optical path) of the reference light LR.

  The data acquisition optical system is not limited to these examples. In general, the data acquisition optical system may include at least one of an optical system of any ophthalmic imaging apparatus and an optical system of any ophthalmic measurement apparatus.

  The two or more imaging units have a configuration for imaging the anterior segment of the eye to be examined from different directions. In the ophthalmologic apparatus 1, the anterior eye cameras 300A and 300B function as two or more imaging units.

  The first alignment unit has a configuration for acquiring first alignment information for performing alignment of the data acquisition optical system with reference to the cornea of the eye to be examined.

  In the ophthalmologic apparatus 1, the first alignment unit may be configured to acquire first alignment information based on two or more captured images acquired by two or more imaging units.

  In the ophthalmologic apparatus 1, the first alignment unit may include a Purkinje image specifying unit 2321 and a first position calculating unit 2322. In this example, the first alignment information includes the processing result (first position) acquired by the first position calculation unit 2322. Note that the first alignment unit may include other elements of the data processing unit 230. For example, the first alignment unit may include an image correction unit 231.

  The ophthalmologic apparatus 1 may include a light beam projection optical system (50) that projects an alignment light beam onto the cornea of the eye to be examined. In this case, the first alignment unit can generate the first alignment information by analyzing two or more captured images acquired by the two or more capturing units when the alignment light beam is projected onto the cornea.

  The second alignment unit acquires second alignment information for performing alignment of the data acquisition optical system with reference to the pupil of the eye E based on two or more captured images acquired by the two or more imaging units. It has the composition of.

  In the ophthalmologic apparatus 1, the second alignment unit may include a pupil center specifying unit 2331 and a second position calculating unit 2332. In this example, the second alignment information includes the processing result (second position) acquired by the second position calculation unit 2332. Note that the second alignment unit may include other elements of the data processing unit 230. For example, the second alignment unit may include an image correction unit 231.

  The position determination unit determines a movement target position of the data acquisition optical system based on the first alignment information acquired by the first alignment unit and the second alignment information acquired by the second alignment unit. In the ophthalmologic apparatus 1, the movement target position determination unit 235 functions as a position determination unit.

  In the ophthalmologic apparatus 1, the movement target position determination unit 235 (position determination unit) may be configured to execute a process of comparing the first alignment information and the second alignment information. Furthermore, the movement target position determination unit 235 may be configured to determine a movement target position based on the first alignment information and the second alignment information when the result of the comparison process satisfies a predetermined condition. On the other hand, when the result of the comparison process does not satisfy the predetermined condition, the movement target position determination unit 235 can execute a predetermined process to determine the movement target position.

  As an example of the comparison process, a difference between the position of the eye to be examined obtained with reference to the cornea and the position obtained with reference to the pupil can be obtained. In this case, the first alignment information includes a first position (Purkinje image position, etc.) acquired with reference to the cornea, and the second alignment information is a second position (pupil center) acquired with reference to the pupil. Position). The movement target position determination unit 235 can calculate the difference between the first position and the second position. Here, the difference between the first position and the second position includes, for example, at least a difference in the xy direction, and may optionally include a difference in the z direction. Furthermore, the movement target position determination unit 235 can determine whether the calculated difference is larger than a predetermined threshold. Then, the movement target position determination unit 235 is controlled to determine the movement target position based on the first position and the second position when it is determined that the difference is larger than the predetermined threshold.

  As a typical example of the process of determining the movement target position based on the first position and the second position, the movement target position determination unit 235 of the ophthalmologic apparatus 1 uses the first position (Purkinje image of the Purkinje image) acquired with reference to the cornea. Position) and a second position (position of the center of the pupil, etc.) acquired with the pupil as a reference, and the movement target position can be determined based on this position. The position between the first position and the second position may be the position of the midpoint of the line segment connecting the first position and the second position, and from this midpoint to the first position side or the second position side It may be a position deviated to.

  In general, the position of the eye E based on the first position and the second position is not limited to the internal dividing point connecting the first position and the second position, and is not limited to the first position or the second position. There may also be an outer dividing point of the line segment. Further, the position of the eye E based on the first position and the second position is not limited to a position on a straight line passing through the first position and the second position, and may be a position deviating from the straight line. .

  The movement target position can be determined according to the pupil size of the eye to be examined. Typically, this processing can be applied when the result of the comparison between the first alignment information and the second alignment information does not satisfy a predetermined condition. When this example is applied, the position determination unit includes a pupil size information acquisition unit that acquires information indicating the pupil size of the eye to be examined. When the pupil size shown in the information acquired by the pupil size information acquisition unit is equal to or smaller than the predetermined threshold, the position determination unit moves the target position based on the position corresponding to the second alignment information (the position of the pupil center, etc.) Can be determined. Thereby, when the eye to be examined is a small pupil eye, it is possible to reduce the possibility that the light beam for acquiring the data of the eye to be vignetted by the iris.

  In a typical example, the pupil size information acquisition unit calculates the pupil size by analyzing the anterior segment imaging system that images the anterior segment of the eye to be examined and the anterior segment image acquired by the anterior segment imaging system. A pupil size calculation unit.

  For example, in the ophthalmologic apparatus 1, at least one of the anterior segment cameras 300A and 300B can be used as the anterior segment imaging system. Alternatively, in the ophthalmologic apparatus 1, the illumination optical system 10 and the photographing optical system 30 can be used as an anterior ocular segment photographing system. As another example, in an ophthalmologic apparatus capable of performing an anterior segment OCT measurement, the anterior segment OCT function can be used as an anterior segment imaging system.

  Further, in the ophthalmologic apparatus 1, the pupil size calculation unit 234 provided in the data processing unit 230 is acquired by at least one of the anterior eye cameras 300A and 300B (or the illumination optical system 10 and the imaging optical system 30). By analyzing the eye image, the pupil size of the eye E can be calculated. Note that the pupil size information acquisition unit may include other elements of the data processing unit 230. For example, the pupil size information acquisition unit may include an image correction unit 231.

  The movement target position can be determined according to the rotation state of the eye to be examined. Typically, this processing can be applied when the result of the comparison between the first alignment information and the second alignment information does not satisfy a predetermined condition. When this example is applied, the ophthalmologic apparatus may include a fixation optical system that outputs fixation light for rotating the eye to be examined. When the fixation light for rotating the eye to be examined from the central fixation position (for example, fixation light for rotating the eye to be examined by a predetermined angle or more from the central fixation position) is output, The movement target position can be determined based on the position corresponding to one alignment information (such as the position of the Purkinje image). Thereby, when the eye to be examined is rotated, it is possible to reduce the possibility that a light beam for acquiring data of the eye to be examined is projected to a position deviating from the corneal apex. Note that the central fixation position indicates, for example, a fixation position corresponding to a position on the optical axis of the fixation optical system. In the above embodiment, the fixation position when the fixation target is displayed at the position where the optical axes intersect on the screen of the LCD 39 (screen center position) corresponds to the central fixation position. The above-mentioned “fixation light for rotating the eye to be examined from the center fixation position” is, for example, from a fixation target displayed at a position separated from the screen center position of the LCD 39 by a predetermined distance (a predetermined number of pixels) or more. It is the output light.

  The ophthalmologic apparatus according to the embodiment can perform an alignment operation based on the movement target position determined by the position determination unit. The alignment mode may be, for example, auto alignment or manual alignment.

  When auto-alignment is performed, the ophthalmologic apparatus includes a first drive unit that moves the data acquisition optical system, and a first control unit that controls the first drive unit based on the movement target position determined by the position determination unit. including.

  In the ophthalmologic apparatus 1, the optical system drive unit 2A functions as a first drive unit, and the main control unit 211 functions as a first control unit.

  When manual alignment is executed, the ophthalmologic apparatus performs a second control unit that displays information based on the movement target position determined by the position determination unit on the display unit, an operation unit, and an operation performed using the operation unit. And a second drive unit that moves the data acquisition optical system according to the above. The display means may be included in the ophthalmologic apparatus or an external display connected to the ophthalmologic apparatus.

  In the ophthalmologic apparatus 1, the main control unit 211 functions as a second control unit, the operation unit 242 functions as an operation unit, and the optical system drive unit 2A functions as a second drive unit. In the ophthalmologic apparatus 1, the display unit 241 is used as a display unit.

  According to the ophthalmologic apparatus according to the embodiment, even if the cornea and pupil of the eye to be examined are eccentric, the position actually measured with reference to the cornea of the eye to be examined and the pupil of the eye to be examined are actually used as a reference. The movement target position of the data acquisition optical system can be determined based on both the measured position and alignment can be performed based on the movement target position. Therefore, it is possible to reduce the possibility that the light beam will be vignetted by the iris by performing alignment with the cornea as a reference, and the possibility that noise light caused by corneal reflection will be mixed by performing alignment with the pupil as a reference.

  Moreover, according to the ophthalmologic apparatus which concerns on embodiment, optimization of z alignment can be aimed at in the ophthalmologic apparatus provided with the ring-shaped aperture stop corresponding to a cornea or a crystalline lens. In conventional ophthalmic devices, when the z alignment is performed based on the cornea due to individual differences such as the anterior chamber depth, the aperture corresponding to the crystalline lens cannot sufficiently perform its function, and conversely, the z alignment is performed based on the pupil. When the operation was performed, the diaphragm corresponding to the cornea could not fully perform its function.

  On the other hand, in the ophthalmologic apparatus according to the embodiment, the alignment (xy alignment and xy alignment) is based on both the position actually measured with reference to the cornea of the eye to be examined and the position actually measured with respect to the pupil of the eye to be examined. z alignment) can be performed. Therefore, regardless of individual differences such as anterior chamber depth, the alignment can be suitably performed based on the position of the cornea of the eye to be examined and the position of the pupil, so that the function of the diaphragm corresponding to the cornea (corneal diaphragm 23c etc.) is also provided. The functions of the diaphragms corresponding to the crystalline lens (the crystalline lens front diaphragm 23f, the crystalline lens rear diaphragm 23r, etc.) can be sufficiently exhibited.

<Modification>
The aspects described above are merely examples for carrying out the present invention. A person who intends to implement the present invention can make arbitrary modifications (omission, replacement, addition, etc.) within the scope of the present invention.

  Although the ophthalmologic apparatus according to the above-described embodiment can execute alignment based on the cornea and alignment based on the pupil, the present invention is not limited to this. In general, the ophthalmologic apparatus according to the embodiment may be configured to be able to execute alignment based on the cornea and alignment based on a predetermined part (part other than the cornea) of the eye to be examined. The predetermined part may be a pupil as in the above embodiment, or may be a part other than the pupil (for example, an iris). The predetermined part may include two or more parts. For example, in the embodiment, the ophthalmologic apparatus may be able to perform alignment based on the cornea, alignment based on the pupil, and alignment based on the iris. In this case, it may be configured to selectively perform alignment based on the pupil and alignment based on the iris.

  Anterior eye cameras 300 </ b> A and 300 </ b> B (two or more photographing units) can be disposed below the lens center of the objective lens 22 (−y direction). Thereby, it is possible to reduce the possibility that the subject's eyelashes or eyelashes appear in the captured images acquired by the anterior eye cameras 300A and 300B. Moreover, even if the subject has a deep eye depression (orbit), anterior segment imaging can be suitably performed.

  In the above-described aspect, the optical path length difference between the optical path of the signal light LS and the optical path of the reference light LR is changed by changing the position of the optical path length changing unit 41. A method of changing this optical path length difference Is not limited to this. For example, it is possible to change the optical path length difference by arranging a reflection mirror (reference mirror) in the optical path of the reference light and moving the reference mirror in the traveling direction of the reference light to change the optical path length of the reference light. Is possible. Further, the optical path length difference may be changed by moving the fundus camera unit 2 or the OCT unit 100 with respect to the eye E to change the optical path length of the signal light LS.

  A computer program for realizing the above-described aspect can be stored in any recording medium readable by a computer. Examples of the recording medium include a semiconductor memory, an optical disk, a magneto-optical disk (CD-ROM / DVD-RAM / DVD-ROM / MO, etc.), a magnetic storage medium (hard disk / floppy (registered trademark) disk / ZIP, etc.), and the like. Can be used.

  It is also possible to send and receive computer programs via a network such as the Internet or a LAN.

DESCRIPTION OF SYMBOLS 1 Ophthalmology apparatus 2 Fundus camera unit 2A Optical system drive part 10 Illumination optical system 23c Corneal diaphragm 23f Lens front diaphragm 23r Lens rear diaphragm 30 Imaging optical system 100 OCT unit 200 Arithmetic control unit 210 Control part 211 Main control part 220 Image formation part 230 Data processing unit 231 Image correction unit 2321 Purkinje image identification unit 2322 First position calculation unit 2331 Pupil center identification unit 2332 Second position calculation unit 234 Pupil size calculation unit 235 Movement target position determination unit 241 Display unit 242 Operation units 300, 300A, 300B Anterior Eye Camera E Eye Ea Anterior Eye Ef Fundus

Claims (12)

A data acquisition optical system for acquiring data of the eye to be examined;
Two or more imaging units for imaging the anterior segment of the eye to be examined from different directions;
A first alignment unit that acquires first alignment information for performing alignment of the data acquisition optical system with reference to the cornea of the eye to be examined;
Based on two or more captured images acquired by the two or more imaging units, a second alignment unit that acquires second alignment information for performing alignment of the data acquisition optical system with reference to a predetermined part of the eye to be examined When,
An ophthalmologic apparatus comprising: a position determining unit that determines a movement target position of the data acquisition optical system based on the first alignment information and the second alignment information. The position determination unit compares the first alignment information with the second alignment information, and when the result of the comparison satisfies a predetermined condition, the position determination unit is based on the first alignment information and the second alignment information. The ophthalmologic apparatus according to claim 1, wherein a movement target position is determined. The first alignment information includes a first position acquired with reference to the cornea,
The second alignment information includes a second position acquired with reference to the predetermined part,
The position determination unit calculates a difference between the first position and the second position, and determines the movement target position based on the first position and the second position when the difference is larger than a predetermined threshold. The ophthalmic apparatus according to claim 2. The ophthalmologic apparatus according to claim 3, wherein the position determination unit obtains a position between the first position and the second position, and determines the movement target position based on the position. The predetermined part is a pupil;
Including a pupil size information acquisition unit that acquires information representing the pupil size of the eye to be examined;
When the pupil size represented in the information acquired by the pupil size information acquisition unit is equal to or smaller than a predetermined threshold, the position determination unit is configured to use the data acquisition optical system based on a position corresponding to the second alignment information. The movement target position is determined. The ophthalmologic apparatus according to claim 1. The pupil size information acquisition unit
An anterior segment imaging system for imaging the anterior segment of the eye to be examined;
The ophthalmologic apparatus according to claim 5, further comprising: a pupil size calculation unit that analyzes an anterior segment image acquired by the anterior segment imaging system and calculates a pupil size. A fixation optical system that outputs fixation light for rotating the eye to be examined from a central fixation position;
When the fixation light is output by the fixation optical system, the position determination unit determines a movement target position of the data acquisition optical system based on a position corresponding to the first alignment information. The ophthalmic apparatus according to claim 1. The ophthalmology according to any one of claims 1 to 7, wherein the first alignment unit acquires the first alignment information based on two or more captured images acquired by the two or more imaging units. apparatus. The first alignment unit includes:
Including a light beam projection optical system that projects an alignment light beam to the cornea of the eye to be examined,
The first alignment information is generated by analyzing two or more photographed images acquired by the two or more photographing units when the alignment light beam is projected onto the cornea. The ophthalmic device described. A first drive unit for moving the data acquisition optical system;
The ophthalmologic apparatus according to claim 1, further comprising: a first control unit that controls the first drive unit based on the movement target position determined by the position determination unit. A second control unit that causes a display unit to display information based on the movement target position determined by the position determination unit;
An operation unit;
The ophthalmologic apparatus according to claim 1, further comprising: a second drive unit that moves the data acquisition optical system in accordance with an operation performed using the operation unit. Data acquisition optics
An illumination optical system including a first diaphragm corresponding to the cornea and a second diaphragm corresponding to a predetermined intraocular region, and projecting illumination light onto the fundus;
The ophthalmologic apparatus according to claim 1, further comprising: an imaging optical system that guides the return light of the illumination light projected onto the fundus by the illumination optical system to an image sensor.

Images