JP2018051391A - Ophthalmologic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ophthalmologic apparatus capable of measuring intraocular distances with high accuracy and without increasing size and complexity of the apparatus.SOLUTION: A photographing part of an ophthalmologic apparatus in an embodiment photographs an eye to be inspected from two or more different directions. An optical system splits light from a light source into measurement light and reference light and detects interference light of returned light of the measurement light from the eye and the reference light. A changing part changes optical path length of the measurement light (reference light). A controller controls the photographing part to perform first photography and the optical system to perform first detection when first optical path length is set and controls the photographing part to perform second photography and the optical system to perform second detection when second optical path length is set. A calculator calculates a displacement between the first and second images, calculates a difference between the first and second optical path lengths, and calculates the distance based on the displacement and the difference, when each of the first and second sites corresponds to a coherence gate.SELECTED DRAWING: Figure 9

Description

  The present invention relates to an ophthalmologic apparatus for measuring a distance in an eye to be examined.

  In the diagnosis in the ophthalmic field, the distance within the eye to be examined is one of important parameters. For example, the axial length indicating the distance between the cornea and the retina is used for diagnosis of axial myopia and axial hyperopia. In addition, the position of the lesion (relative position with respect to the feature point of the eye to be examined) and the size (distance from one end to the other end) are also important diagnostic materials. Hereinafter, such a distance in the eye to be examined may be referred to as “intraocular distance”. As a method for measuring the intraocular distance, a method using an ultrasonic wave and a method using an optical coherence tomography (OCT) are known.

JP 2008-161218 A JP 2007-275375 A

  When measuring the intraocular distance using OCT, it is necessary to individually detect the return light of the measurement light from each of the two parts (referred to as the first part and the second part) at both ends of the distance. . This detection operation includes simultaneous detection and non-simultaneous detection.

  When simultaneous detection is applied, an optical configuration is required to form two reference light paths corresponding to the return light from the two parts. For example, this optical configuration includes a first reference mirror for forming a first reference optical path corresponding to the return light from the first part, and a second reference corresponding to the return light from the second part. A second reference mirror for forming a reference optical path; and a drive mechanism for independently moving the first reference mirror and the second reference mirror. Therefore, simultaneous detection has a disadvantage that the configuration of the apparatus becomes complicated and large.

  On the other hand, when non-simultaneous detection is applied, detection of the return light from the first part and detection of the return light from the second part are performed at different timings. And the orientation may change. Therefore, non-simultaneous detection has the disadvantage that the accuracy of measurement is reduced.

  An object of the present invention is to provide an ophthalmologic apparatus capable of measuring an intraocular distance with high accuracy without increasing the size and complexity of the apparatus.

The ophthalmologic apparatus according to the first aspect of the embodiment includes an imaging unit, an optical system, a changing unit, a control unit, and a calculation unit. The imaging unit images the eye to be examined from two or more different directions. The optical system divides the light from the light source into measurement light and reference light, and detects interference light between the return light of the measurement light from the eye to be examined and the reference light. The changing unit changes the optical path length of the measurement light and / or the reference light. The control unit causes the first imaging by the imaging unit and the first detection by the optical system to be executed when the first optical path length is set by the changing unit, and further, the second optical path length is set. The second imaging by the imaging unit and the second detection by the optical system are executed. The computing unit is configured to calculate the first image acquired by the first imaging, the second image acquired by the second imaging, the first optical path length, and the second optical path length. The distance between the first part of the eye to be examined through which the measurement light has passed in the first detection and the second part through which the measurement light has passed in the second detection is obtained. Further, when each of the first part and the second part corresponds to a coherence gate, the calculation unit calculates a displacement between the first image and the second image, and calculates the first optical path length and the first optical path length. 2 is calculated, and the distance is calculated based on the displacement and the difference.
The ophthalmologic apparatus according to the second aspect of the embodiment includes an imaging unit, an optical system, a changing unit, a control unit, and a calculation unit. The imaging unit images the eye to be examined from two or more different directions. The optical system divides the light from the light source into measurement light and reference light, and detects interference light between the return light of the measurement light from the eye to be examined and the reference light. The changing unit changes the optical path length of the measurement light and / or the reference light. The control unit causes the first imaging by the imaging unit and the first detection by the optical system to be executed when the first optical path length is set by the changing unit, and further, the second optical path length is set. The second imaging by the imaging unit and the second detection by the optical system are executed. The computing unit is configured to calculate the first image acquired by the first imaging, the second image acquired by the second imaging, the first optical path length, and the second optical path length. The distance between the first part of the eye to be examined through which the measurement light has passed in the first detection and the second part through which the measurement light has passed in the second detection is obtained. Furthermore, when at least one of the first part and the second part corresponds to a position away from the coherence gate, the calculation unit calculates a first displacement between the first image and the second image. , Calculating a second displacement between the position away from the coherence gate and the coherence gate, calculating a difference between the first optical path length and the second optical path length, and calculating the first displacement, the second displacement, and The distance is calculated based on the difference.

  According to the ophthalmologic apparatus of the present invention, the intraocular distance can be measured with high accuracy without increasing the size and complexity of the 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 the schematic for demonstrating the operation example of the ophthalmologic apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the ophthalmologic apparatus which concerns on embodiment. It is a flowchart showing the operation example of the ophthalmologic apparatus which concerns on embodiment. It is a flowchart showing the operation example of the ophthalmologic apparatus which concerns on embodiment. It is a flowchart showing the operation example of the ophthalmologic apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the ophthalmologic apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the ophthalmologic apparatus which concerns on embodiment. It is a flowchart showing the operation example of the ophthalmologic apparatus which concerns on embodiment. It is a schematic diagram showing an example of composition of an ophthalmology device concerning an embodiment. It is a flowchart showing the operation example of the ophthalmologic apparatus which concerns on embodiment.

  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 has a function of measuring an intraocular distance using OCT. In this specification, images acquired by OCT may be collectively referred to as OCT images. Further, a measurement operation for forming an OCT image may be referred to as OCT or OCT measurement. In addition, it is possible to use suitably the description content of the literature described in this specification as the content of the following embodiment.

  In the following embodiment, a coherence tomometer using a so-called Spectral Domain type OCT equipped with a low-coherence light source and a spectroscope will be described. However, types other than the spectral domain, for example, a swept source type and an infath type are described. The present invention can also be applied to an optical coherence tomography using the OCT method. Note that the swept source OCT scans (wavelength sweeps) the wavelength of the light irradiated to the object to be measured, and the interference light obtained by superimposing the reflected light of each wavelength and the reference light. This is a technique for obtaining a spectral intensity distribution by sequentially detecting and imaging the form of an object to be measured by applying a Fourier transform thereto. Further, in-face OCT is to irradiate the object to be measured with light having a predetermined beam diameter and analyze the component of the interference light obtained by superimposing the reflected light and the reference light. This is a method of forming an image of the object to be measured in a cross section (C cross section) orthogonal to the traveling direction of light, and is also called a full-field type.

  Moreover, although the following embodiment demonstrates the apparatus which combined the OCT apparatus and the fundus camera, the application object of this invention is not limited to such a multifunctional machine. For example, the present invention can also be applied to a multi-function machine composed of other combinations or an ophthalmic optical coherence tomography as a single machine. In addition, as an example of a complex machine, a complex machine composed of a combination of an OCT apparatus and a scanning laser optometry apparatus (SLO), a complex machine composed of a combination of an OCT apparatus and a slit lamp microscope, and a combination of an OCT apparatus and a surgical microscope There is a multi-function machine. In addition, the present invention can be applied to a multi-function machine composed of a combination of three or more types of devices.

<First Embodiment>
[Constitution]
As shown in FIG. 1, the ophthalmologic apparatus 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 computer that executes various arithmetic processes and control processes.

[Fundus camera unit]
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, such as 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. 4A and 4B. In FIG. 4A and FIG. 4B, 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 irradiates the fundus oculi Ef with illumination light. The photographing optical system 30 guides the fundus reflection light of the illumination light to an imaging device (CCD image sensor (sometimes simply referred to as a CCD) 35, 38). Further, the imaging optical system 30 guides the measurement light from the OCT unit 100 to the fundus oculi Ef and guides the measurement light passing through the fundus oculi Ef to the OCT unit 100.

  The observation light source 11 of the illumination optical system 10 is configured by, for example, an LED (Light Emitting Diode) or 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 reflection surface, passes through the condensing lens 13, passes through the visible cut filter 14, and is converted into near infrared light. Become. Further, the observation illumination light is once converged in the vicinity of the photographing light source 15, reflected by the mirror 16, and passes through the relay lenses 17 and 18, the diaphragm 19 and the relay lens 20. Then, the observation illumination light is reflected at 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.

  The fundus reflection light of the observation illumination light is refracted by the objective lens 22, passes through the dichroic mirror 46, passes through the hole formed in the central region of the perforated mirror 21, passes through the dichroic mirror 55, and is a focusing lens. It is reflected by the mirror 32 via 31. Furthermore, the fundus reflection 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 fundus reflected light at a predetermined frame rate, for example. On the display device 3, an image (observation image) based on fundus reflection light detected by the CCD image sensor 35 is displayed. When the photographing optical system is focused on the anterior segment, an observation image of the anterior segment of the eye E is displayed.

  The imaging light source 15 is constituted by, for example, an LED or a xenon lamp. The light (imaging illumination light) output from the imaging light source 15 is applied to the fundus oculi Ef through the same path as the observation illumination light. The fundus reflection light of the imaging illumination light 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 of the CCD image sensor 38. An image is formed on the light receiving surface. On the display device 3, an image (captured image) based on fundus reflection light detected by the CCD image sensor 38 is displayed. Note that the display device 3 that displays the observation image and the display device 3 that displays the captured image may be the same or different. In addition, when similar imaging is performed by illuminating the eye E with infrared light, an infrared captured image is displayed.

  An LCD (Liquid Crystal Display) 39 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 and the dichroic mirror 55, passes through the hole of the perforated mirror 21, and reaches the dichroic. The light passes through the mirror 46, is refracted by the objective lens 22, and is projected onto the fundus oculi Ef.

  By changing the display position of the fixation target on the screen of the LCD 39, the fixation position of the eye E can be changed. As the fixation position of the eye E, for example, a position for acquiring an image centered on the macular portion of the fundus oculi Ef, or a position for acquiring an image centered on the optic disc as in the case of a conventional fundus camera And a position for acquiring an image centered on the fundus center between the macula and the optic disc (intersection between the fundus Ef and the eye axis). It is also possible to arbitrarily change the display position of the fixation target.

  Further, the fundus camera unit 2 is provided with an alignment optical system 50 and a focus optical system 60 as in a conventional fundus camera. The alignment optical system 50 generates an index (alignment index) for performing alignment (alignment) of the apparatus optical system with respect to the eye E. The focus optical system 60 generates an index (split index) for focusing on the fundus oculi Ef.

  The light (alignment light) output from the LED 51 of the alignment optical system 50 is reflected by the dichroic mirror 55 via the apertures 52 and 53 and the relay lens 54, passes through the hole of the perforated mirror 21, and reaches the dichroic mirror 46. And is projected onto the cornea of the eye E by the objective lens 22.

  The corneal reflection light of the alignment light passes through the objective lens 22, the dichroic mirror 46 and the hole, part of which passes through the dichroic mirror 55, passes through the focusing lens 31, is reflected by the mirror 32, and is half mirror The light passes through 39A, is reflected by the dichroic mirror 33, and is projected onto the light receiving surface of the CCD image sensor 35 by the condenser lens. The light reception image (alignment index) by the CCD image sensor 35 is displayed on the display device 3 together with the observation image. The user performs alignment by performing the same operation as that of a conventional fundus camera. Further, the arithmetic control unit 200 may perform alignment by analyzing the position of the alignment index and moving the optical system (auto-alignment function). In this embodiment, since auto-alignment can be performed using an anterior segment camera 300 described later, it is not essential that auto-alignment using an alignment index is possible. However, the auto-alignment using the alignment index can be performed when the auto-alignment using the anterior segment camera 300 is not successful, or the auto-alignment using the anterior segment camera 300 and the alignment index are used. It is also possible to configure such that automatic alignment can be selectively used.

  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, is reflected by the perforated mirror 21, passes through the dichroic mirror 46, is refracted by the objective lens 22, and is projected onto the fundus oculi Ef.

  The fundus reflection light of the focus light is detected by the CCD image sensor 35 through the same path as the cornea reflection light of the alignment light. 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 and 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 photography. The dichroic mirror 46 reflects light in a wavelength band used for OCT measurement and transmits light for fundus photographing. 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 measurement light LS. This change in the optical path length is used for correcting the optical path length according to the axial length of the eye E to be examined, adjusting the interference state, and changing the OCT measurement target site (fundus Ef, anterior eye portion Ea, etc.). Is done. The optical path length changing unit 41 includes, for example, a corner cube and a mechanism for moving the corner cube. The optical path length changing unit 41 is used to change the optical path length difference between the optical path of the measurement light LS (measurement optical path) and the optical path of the reference light LR (reference optical path). In this embodiment, it is possible to change the length of the measurement optical path by moving the entire optical system in the front-rear direction (z direction) using the optical system driving unit 2A.

  In this embodiment, the optical path length difference is changed by changing the length of the measurement optical path (measurement optical path length). However, the configuration for changing the optical path length difference is not limited to this. For example, the optical path length difference can be changed by providing a configuration for changing the length of the reference optical path (reference optical path length). Further, both a configuration for changing the measurement optical path length and a configuration for changing the reference optical path length may be provided. The configuration for changing the measurement optical path length is not limited to the optical path length changing unit 41 of this embodiment, and may be any configuration capable of realizing the function. Similarly, the configuration for changing the reference optical path length may be arbitrary.

  Further, the configuration for changing the optical path length is not limited to the configuration for changing the length of the optical path in real space. For example, in order to change the optical distance of the optical path, such as a configuration in which a member or material having a predetermined refractive index can be disposed in at least a part of the optical path, or a configuration in which the refractive index of a member disposed in the optical path is changed It is possible to apply any configuration.

  The means for changing the optical path length may be a unit (attachment) that can be attached to the ophthalmologic apparatus 1. For example, a configuration in which an anterior ocular segment attachment is attached to an ophthalmologic apparatus capable of OCT measurement of the fundus, or an ocular fundus attachment is attached to an ophthalmic apparatus capable of OCT measurement of the anterior ocular segment. It is possible to apply a configuration. Such an attachment is disposed between the objective lens 22 and the eye E, for example. At this time, the attachment can be arranged at a position outside the imaging field of the anterior segment camera 300.

  The galvano scanner 42 changes the traveling direction of light (measurement light LS) passing through the optical path for OCT measurement. Thereby, the eye E can be scanned with the measurement light LS. The galvano scanner 42 includes, for example, a galvanometer mirror that scans the measurement light LS in the x direction, a galvanometer mirror that scans in the y direction, and a mechanism that drives these independently. Thereby, the measurement 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 segment camera 300 images the anterior segment Ea substantially simultaneously from different directions. In this embodiment, two cameras are provided on the subject-side surface of the fundus camera unit 2 (see anterior eye cameras 300A and 300B shown in FIG. 4A). Further, as shown in FIGS. 1 and 4A, the anterior eye cameras 300A and 300B are provided at positions deviated from the optical path of the illumination optical system 10 and the optical path of the imaging optical system 30, respectively. That is, the anterior eye cameras 300 </ b> A and 300 </ b> B are provided non-coaxially with the illumination optical system 10 and the imaging optical system 30. Hereinafter, the two anterior eye cameras 300A and 300B 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 according to the embodiment may be an arbitrary number of 2 or more (however, an alignment index is used). In some cases, it is not necessary to provide an anterior eye camera). However, in consideration of the arithmetic processing described later, a configuration that can photograph the anterior segment substantially simultaneously 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. . That is, one of the two or more anterior segment cameras may be carried by a configuration including the imaging optical system 30. Anyway, this embodiment should just be comprised so that imaging | photography of the anterior ocular segment can be carried out substantially simultaneously from two different (or more) directions.

  Note that “substantially simultaneously” indicates that a photographing timing shift that allows negligible eye movement is allowed in photographing with two or more anterior segment cameras. 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, the above-described substantially simultaneous anterior ocular shooting can be realized by controlling the shooting start timing to match or by controlling the frame rate and shooting timing of each frame. Moreover, you may comprise so that the signal input simultaneously substantially simultaneously with respect to the control part 210 (after-mentioned) from two or more anterior eye part cameras may be matched. On the other hand, in the case of still image shooting, this can be realized by executing control to match the shooting timing.

[OCT unit]
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 eye E. This optical system has the same configuration as a conventional spectral domain type OCT apparatus. That is, this optical system divides the light (low coherence light) from the light source into reference light and measurement light, and causes interference between the return light of the measurement light from the eye E and the reference light via the reference light path. It is configured to generate light and detect a spectral component of the interference light. This detection result (detection signal) is sent to the arithmetic control unit 200.

  In the case of a swept source type OCT apparatus, a wavelength swept light source is provided instead of a light source that outputs a low coherence light source, and an optical member that spectrally decomposes interference light is not provided. 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 longer wavelength band, 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 is divided into the measurement 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. The polarization adjuster 106 is, for example, a device that adjusts the polarization state of the reference light LR guided in the optical fiber 104 by applying a stress from the outside to the optical fiber 104 in a loop shape. 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 measurement 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 measurement 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, and the relay lens 45. Then, the measurement light LS is reflected by the dichroic mirror 46, refracted by the objective lens 22, and irradiated to the eye E. The measurement light LS is scattered and reflected at various depth positions of the eye E. The backscattered light (return light) of the measurement light LS from the eye E travels in the reverse direction on the same path as the forward path, is guided to the fiber coupler 103, and reaches the fiber coupler 109 via the optical fiber 108.

  The fiber coupler 109 causes the backscattered light of the measurement 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, dispersed (spectral decomposition) by the diffraction grating 113, condensed by the condenser lens 114, and projected onto the light receiving surface of the CCD image sensor 115. Although the diffraction grating 113 shown in FIG. 2 is a transmission type, other types of spectroscopic elements such as a reflection type diffraction grating may be used.

  The CCD image sensor 115 is a line sensor, for example, and detects each spectral component of the split interference light LC and converts it into electric charges. The CCD image sensor 115 accumulates this electric charge, generates a detection signal, and sends it to the arithmetic control unit 200.

  In this embodiment, a Michelson type interferometer is employed, but any type of interferometer such as a Mach-Zehnder type can be appropriately employed. Further, in place 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]
The configuration of the arithmetic control unit 200 will be described. The arithmetic control unit 200 analyzes the detection signal input from the CCD image sensor 115 to form an OCT image of the eye E. The arithmetic processing for this is the same as that of a conventional spectral domain type OCT apparatus.

  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 eye E 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 and the LEDs 51 and 61, the operation control of the LCD 39, the movement control of the focusing lenses 31 and 43, and the reflector 67. Movement control, 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.

  As control of the OCT unit 100, the arithmetic control unit 200 performs operation control of the light source unit 101, operation control of the optical attenuator 105, operation control of the polarization adjuster 106, operation control of the CCD image sensor 115, and the like.

  The arithmetic control unit 200 includes, for example, a microprocessor, 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 circuit boards, for example, a circuit board 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 cases. It may be.

[Control system]
The configuration of the control system of the ophthalmologic apparatus 1 will be described with reference to FIG.

(Control part)
The control system of the ophthalmologic apparatus 1 is configured around the control unit 210. The control unit 210 includes, for example, the aforementioned microprocessor, RAM, ROM, hard disk drive, communication interface, and the like. The control unit 210 includes a main control unit 211, a storage unit 212, an optical system position acquisition unit 213, and an information determination unit 214.

(Main control unit)
The main control unit 211 performs the various operation controls described above. The movement control of the focusing lens 31 is to move the focusing lens 31 in the optical axis direction by controlling a focusing drive unit (not shown). Thereby, the focus position of the photographic optical system 30 is changed. The movement control of the focusing lens 43 is to move the focusing lens 43 in the optical axis direction by controlling a focusing drive unit (not shown). Thereby, the focus position of the measurement light LS is changed.

  The main control unit 211 can control the optical system driving unit 2A to move the optical system provided in the fundus camera unit 2 three-dimensionally. This control is executed in auto alignment and tracking. Here, tracking refers to moving the apparatus optical system in accordance with the eye movement of the eye E. Tracking is performed, for example, at a later stage than alignment (in some cases, focusing is also performed in advance). 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.

  Note that the optical system drive unit 2A of this embodiment moves the optical system mounted on the fundus camera unit 2, but the optical system mounted on the fundus camera unit 2 and the optical system mounted on the OCT unit 100. May be moved by the optical system driving unit 2A. The optical system driving unit 2A is an example of a “moving mechanism”.

  In addition, since the anterior eye camera 300 of this embodiment is provided in the housing of the fundus camera unit 2, the anterior eye camera 300 is moved by controlling the optical system driving unit 2A (imaging moving unit). Can do. Further, it is possible to provide a photographing moving unit that can independently move two or more anterior eye camera 300. Specifically, the imaging moving unit may include a drive mechanism (an actuator, a power transmission mechanism, etc.) provided for each anterior eye camera 300. The imaging 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.

  Further, the main control unit 211 performs processing for writing data into the storage unit 212 and processing for reading data from the storage unit 212.

(Memory part)
The storage unit 212 stores various data. Examples of the data stored in the storage unit 212 include OCT image image data, fundus image data, and examined eye information. 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 various programs and data for operating the ophthalmologic apparatus 1.

  The storage unit 212 stores aberration information 212a in advance. In the aberration information 212a, information regarding distortion aberration generated in the captured image due to the influence of the optical system mounted on each anterior eye 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 212a can be said to be a parameter obtained by quantifying the distortion that these optical elements give to the captured image.

  An example of a method for generating the aberration information 212a 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 212a of the anterior eye camera 300 by analyzing a plurality of acquired 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 the aberration information 212a 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 212a is configured as information (for example, table information) in which the identification information of each anterior segment camera 300 is associated with the correction coefficient corresponding thereto. The aberration information 212a generated in this way is stored in the storage unit 212 by the main control unit 211. Such generation of aberration information 212a and aberration correction based on this generation are referred to as camera calibration.

(Optical system position acquisition unit)
The optical system position acquisition unit 213 acquires the current position of the optical system mounted on the ophthalmologic apparatus 1. The optical system is an optical system used to optically inspect the eye E. An optical system in the ophthalmologic apparatus 1 (a complex machine of a fundus camera and an OCT apparatus) of this embodiment is an optical system for obtaining an image of the eye to be examined.

  The optical system position acquisition unit 213 receives, for example, information indicating the content of movement control of the optical system driving unit 2A by the main control unit 211, and acquires the current position of the optical system moved by the optical system driving unit 2A. 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 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 optical system based on the control content.

  Further, every time 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 every time the optical system position acquisition unit 213 receives the control content, the current position of the optical system is transmitted. May be obtained sequentially.

  As another configuration example, a position sensor that detects the position of the optical system may be provided in the optical system position acquisition unit 213.

  When the current position of the optical system is acquired by the optical system position acquisition unit 213 as described above, the main control unit 211 determines the acquired current position and 3 of the eye E to be examined obtained by the analysis unit 231 described later. Based on the dimension position, the optical system can be moved to the optical system driving unit 2A. Specifically, the main control unit 211 recognizes the current position of the optical system based on the acquisition result by the optical system position acquisition unit 213, and recognizes the three-dimensional position of the eye E based on the analysis result by the analysis unit 231. Then, the main control unit 211 changes the position of the optical system from the current position of the optical system so that the position of the optical system with respect to the three-dimensional position of the eye E has a predetermined positional relationship. This predetermined positional relationship is such that the positions in the x direction and the y direction coincide with each other and the distance in the z direction becomes a predetermined working distance. Here, the working distance is a predetermined value called a working distance, and means a distance between the eye E and the optical system at the time of examination using the optical system.

(Information judgment part)
The information determination unit 214 determines whether information acquired by performing OCT is appropriate for executing OCT. Information acquired by OCT includes a detection signal from the CCD image sensor 115 of the OCT unit 100 and information obtained by performing predetermined processing on the detection signal. Examples of the latter include the following information: a cross-sectional image (A scan image, two-dimensional cross-sectional image) formed by the image forming unit 220 based on the detection signal; information obtained in the middle of this cross-sectional image forming process; Information (image or the like) formed by the data processing unit 230 based on one or more cross-sectional images formed by the image forming unit 220; information obtained by performing other processing on the detection signal.

  An example of determination processing based on the detection signal from the CCD image sensor 115 will be described. The information determination unit 214 analyzes the detection signal to obtain information (characteristic information) indicating the characteristic, and determines whether or not the characteristic information is appropriate for executing the OCT. The type of characteristic information is determined in advance based on, for example, the influence of factors that disturb the light existing in the eye on the measurement light LS (that is, the influence on the interference light LC).

  An example of characteristic information is intensity (amplitude, etc.). For example, when the measurement light LS passes through the turbid site in the eye E, the intensity of the measurement light LS decreases, and as a result, the intensity of the interference light LC decreases. The information determination unit 214 obtains the intensity of the detection signal obtained by detecting the interference light LC, and compares this intensity with a threshold value. If the intensity is less than or equal to the threshold, the information determination unit 214 determines that this detection signal is inappropriate. This threshold value is determined in advance based on, for example, the intensity of light output from the light source unit 101. Note that the threshold is determined by considering various factors such as the light split ratio by the fiber coupler 103, the light attenuation by the optical member, and the standard light attenuation by passing through the inside of a normal eye. You can also. Examples of characteristic information other than signal strength include noise amount and SN ratio.

  Even when considering information obtained in the middle of cross-sectional image formation processing or information obtained by performing processing other than image formation processing on the detection signal, the same processing as when considering the detection signal should be applied. Is possible. The same applies to the case of considering information (for example, information other than an image) formed by the data processing unit 230 based on one or more cross-sectional images formed by the image forming unit 220.

  An example of processing executed by the information determination unit 214 will be described. This determination process relates to a process called auto Z. The auto Z is a function for drawing an image of the eye E in a predetermined range (target range) within the frame of the OCT image (cross-sectional image).

  In auto Z, the same position of the eye E is repeatedly scanned. The trajectory of each scan is, for example, a line segment shape (line scan). The information determination unit 214 draws an image of a predetermined tissue (the fundus surface, the cornea surface, a high-luminance layer tissue, etc.) of the eye E by analyzing each of the cross-sectional images sequentially obtained by this repetitive scanning. The depth position (position in the z direction (depth direction)) in the frame being specified is specified in real time. Furthermore, the information determination unit 214 calculates a displacement between the specified depth position and the target range. The main control unit 211 adjusts the optical path length difference between the measurement light LS and the reference light LR so as to cancel the calculated displacement, that is, so that an image of a predetermined tissue is drawn in the target range.

  The adjustment of the optical path length difference is performed by controlling the optical path length changing unit 41 to change the optical path length of the measurement light LS. It is also possible to apply a configuration that changes the optical path length of the reference light (for example, a movable reference mirror described later). Further, both a configuration for changing the optical path length of the measurement light and a configuration for changing the optical path length of the reference light may be applied.

  The main control unit 211 and the information determination unit 214 execute the above processing for each cross-sectional image acquired by repetitive scanning (or at a predetermined interval). The information determination unit 214 determines that the auto-Z has succeeded when the displacement is equal to or less than the threshold value by a predetermined timing, that is, when an image of a predetermined tissue is drawn in the target range by the predetermined timing.

  Conversely, if the displacement does not fall below the threshold by a predetermined timing, that is, if an image of a predetermined tissue is not drawn in the target range by the predetermined timing, the information determination unit 214 fails the auto-Z. It is determined that The predetermined timing is set in advance, for example, as the number of times the displacement and the threshold are compared, or as the elapsed time from the start of auto Z.

  Although details will be described later, in this embodiment, the distance between the two parts is obtained by executing OCT measurement of two parts (for example, the cornea and the retina) of the eye E. In such processing, auto-Z can be performed as preparation for OCT measurement. This auto Z is intended to place a predetermined part of the eye E to be examined at a predetermined position in the frame.

  For example, when obtaining the axial length as the intraocular distance, auto Z is executed with the intention of placing the corneal surface (for example, the corneal apex) at a position in the frame corresponding to the coherence gate, and then the corneal surface is included. Perform OCT measurement of the region. Furthermore, auto-Z is executed with the intention of placing the retina surface (for example, the retina center) at a position in the frame corresponding to the coherence gate, and thereafter, OCT measurement of the region including the retina surface is executed. The processing according to this embodiment can be executed regardless of whether Auto Z is successful or not. The coherence gate indicates a position where the difference between the measurement optical path length and the reference optical path length is zero.

(Image forming part)
The image forming unit 220 forms image data of a cross-sectional image of the eye E based on the detection signal from the CCD image sensor 115. This process includes processes such as noise removal (noise reduction), filter processing, FFT (Fast Fourier Transform), and the like, similar to the conventional spectral domain type OCT. When another type of OCT is applied, the image forming unit 220 executes a known process corresponding to the type.

  The image forming unit 220 includes, for example, the circuit board described above. In this specification, “image data” and “image” based thereon may be identified.

(Data processing part)
The data processing unit 230 performs various types of image processing and analysis processing on the image formed by the image forming unit 220. For example, the data processing unit 230 executes various correction processes such as image brightness correction and dispersion correction. Further, the data processing unit 230 performs various types of image processing and analysis processing on the image (fundus image, anterior eye image, etc.) obtained by the fundus camera unit 2.

  The data processing unit 230 performs known image processing such as interpolation processing for interpolating pixels between cross-sectional images to form three-dimensional image data of the eye E. The three-dimensional image data means image data in which pixel positions are defined by a three-dimensional coordinate system. As the three-dimensional image data, there is image data composed of voxels arranged three-dimensionally. This image data is called volume data or voxel data. When displaying an image based on volume data, the data processing unit 230 performs rendering processing (volume rendering, MIP (Maximum Intensity Projection), etc.) on the volume data, and views the image from a specific gaze direction. Image data of a pseudo three-dimensional image is formed. The pseudo three-dimensional image is displayed on the display unit 241.

  It is also possible to form stack data of a plurality of cross-sectional images as 3D image data. The stack data is image data obtained by three-dimensionally arranging a plurality of cross-sectional images obtained along a plurality of scanning lines based on the positional relationship of the scanning lines. That is, stack data is image data obtained by expressing a plurality of cross-sectional images originally defined by individual two-dimensional coordinate systems by one three-dimensional coordinate system (that is, by embedding them in one three-dimensional space). is there.

  Further, the data processing unit 230 can form a cross-sectional image at an arbitrary cross-section based on the three-dimensional image data. This process is called section conversion or multi-planar reconstruction, and includes a process of extracting pixels (voxels) located in a specified section and a process of arranging the extracted pixels. .

  Further, the data processing unit 230 is provided with an analysis unit 231, an image determination unit 232, an image specification unit 233, and a distance calculation unit 234.

(Analysis Department)
The analysis unit 231 obtains the three-dimensional position of the eye E by analyzing two or more captured images obtained substantially simultaneously by the two or more anterior segment cameras 300. As an example of a configuration for executing this processing, the analysis unit 231 includes an image correction unit 2311, a feature position specifying unit 2312, and a three-dimensional position calculation unit 2313.

(Image correction unit)
The image correction unit 2311 corrects the distortion of each captured image obtained by the anterior eye camera 300 based on the aberration information 212 a 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 212a and the image correction unit 2311 do not have to be provided when the distortion aberration given to the captured image by the optical system of the anterior eye camera 300 is sufficiently small.

(Feature position identification part)
The feature position specifying unit 2312 analyzes each captured image (the distortion of which has been corrected by the image correcting unit 2311), thereby analyzing a position (feature position) in the captured image corresponding to a predetermined feature part of the anterior segment Ea. Specified). For example, the center of the pupil of the eye E or the apex of the cornea is used as the predetermined characteristic part. Hereinafter, a specific example of the process of specifying the pupil center will be described.

  First, the feature position specifying unit 2312 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 drawn with lower brightness than other parts, the pupil area can be specified by searching for the low brightness image area. 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 feature position specifying unit 2312 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 this contour (approximate circle or approximate ellipse) 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 the feature position corresponding to another feature part is specified, it is possible to specify the feature position based on the distribution of pixel values of the photographed image in the same manner as described above.

(3D position calculator)
The three-dimensional position calculation unit 2313 determines the characteristic part of the eye E based on the positions of the two or more anterior eye camera 300 and the feature positions in the two or more captured images specified by the feature position specifying unit 2312. A three-dimensional position is calculated. This process will be described with reference to FIGS. 5A and 5B.

  FIG. 5A is a top view showing the positional relationship between the eye E and the anterior eye cameras 300A and 300B. FIG. 5B 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”. The distance (imaging distance) between the baselines of the two anterior eye cameras 300A and 300B and the characteristic part 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 three-dimensional position calculation unit 2313 is shown in FIGS. 5A and 5B with respect to the positions (known) of the two anterior eye cameras 300A and 300B and the characteristic position corresponding to the characteristic part P in the two captured images. By applying a known trigonometric method that takes into account the arrangement relationship shown, the three-dimensional position of the characteristic part P, that is, the three-dimensional position of the eye E to be examined is calculated.

  The three-dimensional position of the eye E calculated by the three-dimensional position calculation unit 2313 is sent to the control unit 210. Based on the calculation result of the three-dimensional position, the control unit 210 adjusts the optical axis of the optical system to the axis of the eye E and makes the distance of the optical system with respect to the eye E to be a predetermined working distance. The optical system driving unit 2A is controlled.

Further, when the anterior eye camera 300 shoots a moving image of the anterior eye part Ea in parallel from different directions, for example, by performing the following processes (1) and (2), an optical system for the movement of the eye E It is possible to perform tracking.
(1) The analysis unit 231 sequentially obtains the three-dimensional position of the eye E by sequentially analyzing two or more frames obtained substantially simultaneously in moving image shooting by the two or more anterior segment cameras 300. .
(2) The control unit 210 sequentially controls the optical system driving unit 2A based on the three-dimensional position of the eye E to be sequentially obtained by the analysis unit 231 so that the position of the optical system follows the movement of the eye E to be examined. Let

  The analysis unit 231 can obtain the displacement between the eye E and the optical system based on the 3D position of the eye E acquired by the 3D position calculation unit 2313. This process is executed using the fact that the position of the anterior eye camera 300 and the position of the optical system are known. The position of the optical system is a predetermined position determined in advance, for example, a position where the front surface of the objective lens 22 (the surface of the eye E) and the optical axis of the optical system intersect.

  Another example of the process for obtaining the displacement between the eye E and the optical system will be described. In this example, an alignment index is projected on the anterior segment of the eye E. Further, the fundus camera unit 2 captures a moving image of the anterior segment where the alignment index is projected. In general, a pair of alignment indices is reflected in each frame acquired by this moving image shooting. The analysis unit 231 calculates a target displacement based on the drawing positions of the pair of alignment indexes.

  This process will be described more specifically. When the optical system is disposed at a predetermined inspectable position with respect to the eye E, the pair of alignment indexes are drawn so as to overlap a predetermined position (for example, the frame center) of the frame. The inspectable position is, for example, that the x coordinate and y coordinate of a predetermined position of the eye E to be examined (corneal vertex, pupil center, etc.) are substantially equal to the x coordinate and y coordinate of the optical axis of the optical system, and The positional relationship between the eye E and the optical system is shown such that the distance between the eye E and the optical system (for example, the objective lens 22) is substantially equal to a predetermined working distance. Also, the drawing position shift (first shift) between the two alignment indexes reflects the displacement from the working distance in the z direction, and the alignment index drawing position shift (second shift) with respect to the predetermined position of the frame. ) Reflects the displacement of the eye E from the predetermined position in the xy direction. Using this relationship, the analysis unit 231 obtains a displacement in the z direction from the first deviation, and obtains a displacement in the xy direction from the second deviation. Thereby, a three-dimensional displacement between the eye E and the optical system is obtained. Such a displacement calculation process is a process executed in a known auto alignment.

(Image judgment part)
The image determination unit 232 analyzes the captured image obtained by at least one of the two or more anterior segment cameras 300, so that the image of the anterior segment Ea is included in a predetermined region in the captured image. Determine whether or not.

  This predetermined area is set in advance within the imaging range of the anterior eye camera 300, and is set as an area including the center of the imaging range, for example. Here, the range of the predetermined region can be changed according to the imaging conditions (the position of the anterior eye camera 300, the imaging magnification, etc.) by the anterior eye camera 300. Further, the range of the predetermined area can be determined according to the setting of feature points described later. Further, the predetermined region can be set so as to correspond to the position of the support portion 440 (chin rest, forehead pad, etc., see FIGS. 4A and 4B) supporting the face of the subject or the vicinity thereof. .

  A specific example of processing executed by the image determination unit 232 will be described. First, the image determination unit 232 specifies an image region corresponding to a predetermined feature point of the anterior eye portion Ea from the captured image. These feature points include the pupil center, pupil contour, iris center, iris contour, and corneal apex. The process for specifying the image area corresponding to the feature point is the same as the process executed by the feature position specifying unit 2312, for example. When the feature point and the feature part are the same, the specification result by the feature position specifying unit 2312 can be used for processing performed by the image determining unit 232.

  Next, the image determination unit 232 determines whether or not the specified feature point is included in a predetermined region in the captured image (frame thereof). This process is performed by comparing the coordinates corresponding to the predetermined area with the coordinates of the feature points.

  The image determination unit 232 sends this determination result to the control unit 210. When it is determined that the image of the anterior segment Ea is not included in the predetermined area, the control unit 210 controls the optical system driving unit 2A (imaging moving unit) to support the anterior segment camera 300 with the support unit 440 ( That is, it is moved in the direction away from the subject's face) and / or the outside of the support portion 440. The direction away from the support portion 440 is the −z direction in the coordinate system shown in FIG. Further, the outward direction of the support portion 440 is a direction in which the anterior eye camera 300 is separated from the optical axis of the optical system. The direction away from the optical system can be defined in the horizontal direction (± x direction) and / or the vertical direction (± y direction). That is, it is possible to define a direction away from the optical system in an arbitrary direction in the xy plane.

  Further, the moving direction and / or moving distance of the anterior eye camera 300 can be set based on, for example, the positional relationship between the anterior eye camera 300 and the support part 440 before the movement. Further, by alternately performing the determination process by the image determination unit 232 and the movement process of the anterior segment camera 300, it is possible to perform control so as to drive the anterior segment camera 300 to a suitable position. . Further, the moving direction and / or moving distance of the anterior eye camera 300 may be determined according to the distance (number of pixels) between the image area corresponding to the feature point and the predetermined area. Further, the moving direction and / or moving distance of the anterior segment camera 300 is determined according to the distance between the image area corresponding to the feature point and a predetermined position (for example, the center position) in the predetermined area. Is also possible.

  Another operation example based on the determination result by the image determination unit 232 will be described. When it is determined that the image of the anterior segment Ea is not included in the predetermined area, the control unit 210 causes the output unit to output predetermined warning information. Examples of the output unit include a display unit 241 and an audio output unit (not shown). When the display unit 241 is used as an output unit, the control unit 210 causes the display unit 241 to display a warning message including predetermined character string information, image information, a pop-up window, and the like. When the audio output unit is used as the output unit, the control unit 210 causes the audio output unit to output predetermined audio information, warning sound, and the like.

  With such warning information, the user recognizes that the image of the anterior segment Ea is not included in the predetermined area. Then, the user moves the anterior eye camera 300 three-dimensionally using the operation unit 242. Note that the control unit 210 may output information (movement information) indicating the movement direction and / or movement distance of the anterior eye camera 300 together with the warning information. This movement information is generated based on the positional relationship between the image area corresponding to the feature point obtained by the image determination unit 232 and the predetermined area, for example. When the manual movement by the user is completed, the determination process by the image determination unit 232 may be performed again.

(Image identification part)
For example, the image specifying unit 233 operates when the anterior eye camera 300 acquires a time-series image. A time-series image means a plurality of still images (frames) arranged in a time series (time axis). The time series image includes a moving image. Here, the moving image is a series of still images acquired in synchronization with the time axis (that is, at regular time intervals) and represents the movement of the subject. Note that the time-series images are not limited to moving images, and for example, the time interval between frames need not be constant.

  The image specifying unit 233 compares substantially the same still image (second image) as the reference image by comparing still images sequentially acquired as time-series images with a predetermined reference image (first image). ). This comparison processing includes arbitrary image processing for determining the identity (similarity) of two images. This image processing may include any of image correlation, feature point extraction, image difference, affine transformation, and the like.

  In this comparison process, the first image and the second image may be images obtained by the two anterior eye cameras 300A and 300B, respectively. In that case, the image specifying unit 233 compares the first image acquired by the anterior segment camera 300A with the second image and / or the first image acquired by the anterior segment camera 300B. The second image is compared. Alternatively, the first image and the second image may be a composite image (for example, a stereoscopic image) of two images acquired substantially simultaneously by the two anterior eye cameras 300A and 300B. In that case, the image specifying unit 233 compares the first image as the composite image with the second image as the composite image.

  “Substantially the same” is intended to allow a difference between two images to a predetermined extent. For example, the image specifying unit 233 stores an allowable range of image correlation values in advance, and determines whether the correlation value obtained by the image correlation during the comparison process is included in the allowable range. If it is determined that the images are within the allowable range, the two compared images are determined to be substantially the same. Still images determined to be substantially the same correspond to the second image. The allowable range is set empirically and / or theoretically in consideration of the purpose of obtaining the intraocular distance (the same applies hereinafter).

  Another example will be described. The image specifying unit 233 stores in advance an allowable range of a difference in arrangement relationship (distance, relative position, etc.) of two or more feature points. A feature point is a position in an image corresponding to an arbitrary part of the eye (for example, the center of the pupil, the periphery of the pupil, etc.). Further, the image specifying unit 233 executes the feature point extraction to thereby arrange the two or more feature points in the first image (reference image) and the two or more in the still images included in the time-series image. The feature point arrangement relationship is acquired. Then, the image specifying unit 233 calculates an index (difference, ratio, etc.) indicating the difference between these two arrangement relationships, and determines whether this index is included in the allowable range. If it is determined that the images are within the allowable range, the two compared images are determined to be substantially the same. Still images determined to be substantially the same correspond to the second image.

  Still another example will be described. The image specifying unit 233 stores in advance a permissible range of information (for example, the number of pixels, pixel value, etc.) regarding the pixels appearing in the difference image. The image specifying unit 233 generates a difference image between the first image (reference image) and a still image included in the time series image. At this time, alignment (such as affine transformation) of the two images can be executed so that two or more feature points are matched. Further, the image specifying unit 233 acquires information regarding the pixels appearing in the generated difference image, and determines whether the acquired information is included in the allowable range. If it is determined that the images are within the allowable range, the two compared images are determined to be substantially the same. Still images determined to be substantially the same correspond to the second image.

(Distance calculation section)
The distance calculation unit 234 performs information obtained in the first OCT measurement performed along with the acquisition of the reference image, and the first image performed along with the acquisition of the image substantially identical to the reference image (the second image). Between the first part included in the scan range in the first OCT measurement and the second part included in the scan range in the second OCT measurement based on the information obtained in the second OCT measurement. Find the distance.

  Here, the information obtained in the OCT measurement includes the optical path length of the measurement optical path or the reference optical path. In particular, in this embodiment, information on the measurement optical path length (for example, the position of the optical path length changing unit 41, the optical path length change). Control content related to movement of the unit 41). Note that, when a configuration in which the reference optical path length can be changed is applied, information on the reference optical path length (for example, the position of the reference mirror, the control content related to the movement of the reference mirror, etc.) is included.

  According to the position of the first part and the second part in information obtained by OCT measurement (for example, information obtained by processing a detection signal, OCT image, detection signal, or OCT image), a distance calculation unit It is possible to change the contents of the processing executed by H.234.

  For example, the content of the process can be changed based on the displacement of the first part relative to the coherence gate (first displacement) and the displacement of the second part relative to the coherence gate (second displacement). These displacements may be, for example, displacements used for determining whether the above-described auto Z is successful.

  When each of the first displacement and the second displacement is within a predetermined threshold (for example, when auto Z is successful), that is, when each of the first portion and the second portion corresponds to a coherence gate, The distance calculator 234 calculates a difference between the measurement optical path length (first optical path length) in the first OCT measurement and the measurement optical path length (second optical path length) in the second OCT measurement. The calculated difference value corresponds to the distance between the first part and the second part.

  On the other hand, when one or both of the first displacement and the second displacement exceed a predetermined threshold (for example, when auto Z fails), that is, at least one of the first portion and the second portion is from the coherence gate. In the case where the distance is equivalent to the distant position, the distance calculator 234 refers to the displacement of the first part and / or the second part with respect to the coherence gate in addition to the first optical path length and the second optical path length described above. The distance between these parts is calculated. As a specific example, the distance calculation unit 234 can execute the following three steps: a first process for calculating a difference between the first optical path length and the second optical path length; And / or a second process for calculating a displacement between the second part and the second part and the coherence gate; first based on the difference obtained in the first process and the displacement obtained in the second process 3rd process which calculates the distance between a site | part and a 2nd site | part.

  In the second process, the displacement amount and the displacement direction are obtained. The displacement amount is calculated based on, for example, the signal position corresponding to the coherence gate and the signal position corresponding to the target site in the A-scan profile. Alternatively, the displacement amount can be calculated based on the image position corresponding to the coherence gate and the image position corresponding to the target site in the OCT image. The displacement direction is obtained based on the positional relationship (known) between the first part and the second part, the signal position corresponding to the coherence gate in the A-scan profile, and the signal position corresponding to the target part. Alternatively, the displacement direction can be obtained based on the positional relationship (known) between the first part and the second part and the image position corresponding to the coherence gate and the image position corresponding to the target part in the OCT image. .

  In the third process, the displacement amount is added to or subtracted from the difference value obtained in the first process according to the displacement direction. Specifically, when the displacement direction of the first part (or the second part) with respect to the coherence gate is the second part side (or the first part side), the displacement amount is subtracted from the difference value. . For example, when the displacement direction of the corneal apex (or retinal center) relative to the coherence gate is the retinal side (or corneal side), the displacement amount is subtracted from the difference value.

  Conversely, when the displacement direction of the first part (or the second part) relative to the coherence gate is the opposite side of the second part (or the opposite side of the first part), the displacement amount is added to the difference value. Is done. For example, when the displacement direction of the corneal apex (or the retina center) with respect to the coherence gate is the opposite side of the retina (or the opposite side of the cornea), the displacement amount is added to the difference value.

  In this embodiment, the first OCT measurement and the second OCT measurement are performed at a timing at which substantially the same image is obtained by the anterior segment camera 300. That is, the first OCT measurement and the second OCT measurement are performed in a state where the relative position of the eye E to the ophthalmologic apparatus 1 is substantially the same. Therefore, this relative position shift is not used in the distance calculation. However, the accuracy of the distance calculation can be improved by taking this relative position shift into consideration. For this purpose, for example, a displacement between the reference image (first image) and the second image is obtained by executing an image comparison similar to that of the image specifying unit 233. Since these images are images acquired by the two anterior eye cameras 300A and 300B, as described above, the three-dimensional position of the eye E at each imaging timing can be obtained (analysis unit). 231, especially see the three-dimensional position calculator 2313). Therefore, the displacement of the relative position obtained from these images represents a three-dimensional displacement (x direction, y direction, z direction). The displacement in the z direction is added to or subtracted from the distance value obtained in the third process, similarly to the process using the displacement direction and the displacement amount obtained in the second process. Further, the displacement in the x direction and the displacement in the y direction are added to the distance value obtained in the third process by using the trigonometric method.

  The data processing unit 230 that functions as described above includes, for example, the aforementioned microprocessor, RAM, ROM, hard disk drive, circuit board, and the like. In a storage device such as a hard disk drive, a computer program for causing the microprocessor to execute the above functions is stored in advance.

(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, an operation panel, or the like 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.

[Operation]
The operation of the ophthalmologic apparatus 1 according to this embodiment will be described. Examples of operations of the ophthalmologic apparatus 1 are shown in FIGS. The operation shown in FIG. 6 shows an example of the basic operation of this embodiment. The operation shown in FIGS. 7A to 7D shows an example of the operation when the above-described auto Z is applied. The operation shown in FIG. 8 shows an example of the operation when the above-described auto alignment using the reference image is applied. In addition, the operation | movement which concerns on this embodiment is not limited to these. For example, two or more of the three operation examples shown in FIGS. 6 to 8 can be combined.

  In the following operation example, it is assumed that patient registration and setting of examination conditions have already been performed. Patient registration is performed by inputting the patient ID of the subject using the user interface 240, for example.

  The inspection conditions may include various conditions (for example, scan patterns, types of analysis processes, etc.) applied in OCT measurement and / or subsequent processing. Such a condition may be a default condition or a condition selected manually or automatically.

  Further, the inspection condition may include a type of intraocular distance that is a measurement purpose. Types of intraocular distance include, for example, names of intraocular distances (eg, axial length, lens-retinal distance), names of end portions of line segments corresponding to intraocular distances (eg, cornea (corneal apex)), Specified by any information necessary to define the intraocular distance, such as the fundus (fundus center), the posterior capsule (the posterior capsule center)). The setting of the intraocular distance may include a process of inputting such information.

  Several examples of processing for setting the type of intraocular distance will be described. A first example will be described. The control unit 210 causes the display unit 241 to display an eye image (eye image). The eye image may include, for example, any of an OCT image, an anterior ocular segment image, a fundus oculi image, an SLO image, and schematic diagrams (such as the anterior ocular segment and the fundus oculi). The eye image may be an image in which the eye E is drawn or an image in which another eye is drawn. When the eye image is an image of the eye E to be examined, this eye image may be an image acquired in the past (past examination, current examination, etc.), or an image (observation image, A real-time OCT image or the like). The user designates a desired position in the displayed eye image using the user interface 240. This designation operation is performed for each of one or more eye images. For example, when it is desired to set the axial length as the type of intraocular distance, the user specifies the corneal apex position in the OCT image of the anterior segment by clicking or touching, and the fundus center in the OCT image of the fundus Specify the position. The control unit 210 stores information (pixel coordinate values, part names, etc.) indicating the designated image position in the storage unit 212. In the subsequent processing, the intraocular distance specified by the image position designated in this way is measured. Further, the designated image position can be used for arbitrary processing such as the above-described auto Z.

  A second example of processing for setting the type of intraocular distance will be described. The control unit 210 causes the display unit 241 to display list information including a plurality of pieces of information indicating a plurality of types of intraocular distances as options, such as the name of an eye part and the name of an intraocular distance. Examples of the list information include a pull-down menu and a list with a check box. The user designates a desired option using the user interface 240. The control unit 210 stores information indicating the selection result of the options in the storage unit 212. In the subsequent processing, the intraocular distance is measured based on the designated option. For example, the data processing unit 230 identifies an image region of a part corresponding to the designated option by analyzing the OCT image. For example, when it is desired to set the axial length as the type of intraocular distance, the user designates the option “ocular axial length” or the options “cornea (corneal apex)” and “fundus (fundus center)”. Based on this designation result, the data processing unit 230 performs a process of specifying an image region corresponding to the corneal apex by analyzing the OCT image of the anterior ocular segment, and analyzes the OCT image of the fundus oculi. Processing for specifying an image region corresponding to the center is executed.

  A third example of processing for setting the type of intraocular distance will be described. The control unit 210 acquires information indicating the type of intraocular distance, such as the name of the eye part and the name of the intraocular distance. This processing is performed with reference to, for example, the names of wounds and diseases recorded in the electronic medical record of the subject, the examination phase in the clinical path, the examination phase in the examination, and the like. Such information is input to the ophthalmologic apparatus 1 from a hospital server via a network, for example. The control unit 210 stores the acquired information in the storage unit 212. In the subsequent processing, the intraocular distance is measured based on the stored information. The processing is the same as in the second example, for example.

  The above preparation is performed before each operation shown in FIGS. In addition, the process performed in a preparation stage is not limited to the above-mentioned thing, For example, you may include the arbitrary preliminary processes currently implemented.

(Operation example 1)
Refer to the flowchart shown in FIG. This example shows an example of the basic operation for obtaining the intraocular distance.

(S1: Start of anterior segment imaging)
When a predetermined instruction is input after the above preparation, the control unit 210 causes the anterior segment camera 300A and 300B to start photographing the anterior segment Ea. This shooting is moving image shooting in which the anterior segment Ea is a shooting target. Each anterior eye camera 300A and 300B shoots a moving image at a predetermined frame rate.

  Here, the imaging timings of the anterior eye cameras 300A and 300B may be synchronized by the control unit 210. Each anterior eye camera 300A and 300B sequentially sends the acquired frames to the control unit 210 in real time. The controller 210 associates the frames obtained by both anterior eye cameras 300A and 300B according to the photographing timing. That is, the control unit 210 associates frames acquired substantially simultaneously by both anterior eye cameras 300A and 300B. This association is executed, for example, based on the above-described synchronization control or based on the input timing of frames from the anterior eye cameras 300A and 300B. The control unit 210 sends a pair of associated frames to the analysis unit 231.

  In addition, the said instruction | indication used as a trigger of imaging | photography start is input when a user operates the user interface 240, for example. Alternatively, the completion of the preparation may be the instruction.

(S2: Alignment)
The ophthalmologic apparatus 1 starts alignment of the optical system with respect to the eye E in response to the start of anterior ocular segment imaging or an instruction from the user. This alignment is executed in order to place the optical system at a position (predetermined relative position with respect to the eye E) for performing OCT measurement of the anterior segment Ea. This alignment is executed based on the anterior segment image acquired in real time by the anterior segment cameras 300A and 300B.

  The alignment based on the anterior segment images (frames) acquired by the anterior segment cameras 300A and 300B is executed as follows, for example. First, the image correction unit 2311 corrects the distortion of each frame sent from the control unit 210 based on the aberration information 212a. The pair of frames whose distortion has been corrected is sent to the feature position specifying unit 2312. The feature position specifying unit 2312 analyzes each frame sent from the image correction unit 2311 to execute a process for specifying the feature position in the frame corresponding to the pupil center of the anterior segment Ea.

  If the identification of the feature position fails, the control unit 210 responds to the reception of the information from the feature position specification unit 2312 and controls the above-described imaging movement unit to support the anterior eye cameras 300A and 300B. It moves to the direction which leaves | separates from 440, and / or the outer side of the support part 440. FIG. When the anterior eye cameras 300A and 300B are moved in the direction away from the support part 440, the distance between the anterior eye cameras 300A and 300B and the subject (eye E) increases, so that the face of the subject It is possible to image a wider range, and the possibility that the eye E to be inspected is arranged in a suitable imageable range by the anterior eye camera 300A and 300B increases. On the other hand, when the anterior eye cameras 300A and 300B are moved in the outward direction of the support part 440, the anterior eye cameras 300A and 300B are moved in the direction of the subject's ear, so that the eye to be examined is in a suitable photographing range. The possibility that E is arranged increases. In addition, by combining these movements in the two directions, the possibility that the eye E to be examined is arranged in a suitable photographing range is further increased.

  After the movement of the anterior eye cameras 300A and 300B is completed, moving image shooting by the anterior eye cameras 300A and 300B, specification of the pupil center, and determination of successful identification are executed again. When this routine is repeated a predetermined number of times, control can be performed so as to shift to automatic alignment using an alignment index or manual alignment.

  When the feature position is successfully identified, the image determination unit 232 determines whether an image corresponding to the anterior segment Ea is located within a predetermined region of the frame. In this operation example, the determination process is executed using the feature position specified by the feature position specifying unit 2312. When it is determined that the image of the anterior segment Ea is not located within the predetermined region of the frame, the movement of the anterior segment cameras 300A and 300B is executed again. On the other hand, when it is determined that the image of the anterior segment Ea is located within a predetermined region of the frame, the three-dimensional position calculation unit 2313 uses the positions of the anterior segment cameras 300A and 300B and the feature position specifying unit 2312. Based on the characteristic position specified for the pair of frames, the three-dimensional position of the pupil center of the eye E is calculated. Then, the control unit 210 adjusts the optical axis of the optical system to the axis of the eye E based on the calculated three-dimensional position, and the distance of the optical system with respect to the eye E becomes a predetermined working distance. Thus, the optical system driving unit 2A is controlled. The alignment is executed as described above.

  In addition, instead of referring to the anterior segment image acquired by the anterior segment cameras 300A and 300B, or in addition to referring to the anterior segment image, it is possible to perform alignment using the alignment index described above. It is. Moreover, you may align manually, referring the observation image of the anterior eye part Ea.

(S3: OCT measurement of cornea)
After completion of the alignment, the ophthalmologic apparatus 1 performs OCT measurement of the cornea (anterior eye portion Ea) of the eye E to be examined. This OCT measurement is executed based on the inspection conditions set in the above preparation. Even at this stage, the anterior ocular segment imaging started in step S1 is continuously performed.

(S4: Storage of OCT data and anterior segment image)
The control unit 210 causes the storage unit 212 to store the OCT data obtained in step S3 and the anterior ocular segment image obtained during the OCT measurement.

  The OCT data includes at least information indicating the optical path length of the optical system (first optical path length information) applied in OCT measurement of the cornea. In this example, since the measurement optical path length is variable, the first optical path length information includes information indicating the measurement optical path length.

  The OCT data may include any of conditions applied in corneal OCT measurement (eg, scan pattern). The OCT data may include data (for example, A-scan profile, cross-sectional image data, etc.) acquired by OCT measurement of the cornea. The OCT data may include data obtained by processing data obtained by corneal OCT measurement (for example, data obtained by analysis processing, data subjected to display processing, etc.). .

  The stored anterior ocular segment image is an image acquired at least at one of the timing immediately before, during, and immediately after the corneal OCT measurement. Here, an error between the OCT measurement timing of the cornea and the acquisition timing of the anterior ocular segment image is permissible as long as it is generally recognized that no eye movement is involved.

  The stored anterior segment image may include a pair of frames acquired substantially simultaneously by the anterior segment cameras 300A and 300B, or acquired by one of the anterior segment cameras 300A and 300B. Only the frame may be included.

(S5: Change of optical path length)
Subsequently, the control unit 210 changes the optical path length of the optical system in order to change the target of OCT measurement from the cornea to the fundus. In this example, the measurement optical path length is changed by controlling the optical path length changing unit 41. The change amount of the optical path length may be a default value. Alternatively, the optical path length can be changed with reference to the image of the eye E (for example, the images taken by the anterior eye cameras 300A and 300B, the observation image by the optical system, etc.).

(S6: Was an anterior ocular segment image substantially the same as that obtained during cornea measurement?)
Even at this stage, the anterior segment imaging started in step S1 is continuously performed. The control unit 210 sequentially sends frames input from the anterior eye camera 300A and / or 300B to the image specifying unit 233. In addition, the control unit 210 sends the anterior segment image stored in the storage unit 212 in step S4 to the image specifying unit 233. This anterior segment image is used as a reference image (first image) in the comparison process by the image specifying unit 233. As described above, this reference image is a frame acquired by one or both of the anterior eye cameras 300A and 300B.

  The image specifying unit 233 compares the frames sequentially input from the control unit 210 with the reference image. This comparison process is repeatedly executed for sequentially input frames until the substantially same frame (second image) as the reference image is specified (S6: NO). In response to specifying the second image, the image specifying unit 233 transmits a signal to the control unit 210 (S6: YES).

  If the second image is not specified even if the comparison process is executed for a predetermined time, or if the second image is not specified even if the comparison process is executed a predetermined number of times, the ophthalmologic apparatus 1 notifies the user. It can be carried out. In this notification process, for example, the control unit 210 causes the display unit 241 to display a message indicating that the second image is not specified, or the control unit 210 causes a sound output unit (not shown) to output a warning sound. Is done. A user who recognizes such notification can manually adjust the position of the optical system, for example.

(S7: OCT measurement of the fundus)
As described above, the image specifying unit 233 transmits a signal to the control unit 210 in response to the fact that substantially the same frame (second image) as the reference image has been specified. Receiving this signal, the control unit 210 causes the ophthalmologic apparatus 1 to perform OCT measurement of the fundus oculi Ef. This OCT measurement is executed based on the inspection conditions set in the above preparation. At this stage, the anterior ocular segment imaging started in step S1 may be continuously performed or may have already been completed.

  The control unit 210 causes the storage unit 212 to store OCT data obtained by OCT measurement of the fundus oculi Ef. The OCT data includes at least information indicating the optical path length of the optical system (second optical path length information) applied in OCT measurement of the fundus oculi Ef. The OCT data may include other data as described above. The control unit 210 may store an anterior ocular segment image obtained during OCT measurement of the fundus oculi Ef together with OCT data. This anterior segment image is, for example, the second image specified in step S6.

(S8: Calculation of intraocular distance)
The control unit 210 reads out the first optical path length information obtained in step S4 and the second optical path length information obtained in step S7 from the storage unit 212, and sends them to the distance calculation unit 234. Based on the first optical path length information and the second optical path length information, the distance calculation unit 234 is included in the first region included in the scan range in the corneal OCT measurement and in the scan range in the OCT measurement of the fundus oculi Ef. The distance (intraocular distance) between the second part is obtained.

  The processing executed by the distance calculation unit 234 in this example will be described. It is assumed that the first part is the corneal apex, the second part is the fundus center, and the intraocular distance is the axial length. In this example, OCT measurement of the fundus oculi Ef is executed at the timing when an anterior ocular segment image substantially identical to the anterior ocular segment image acquired together with the corneal OCT measurement is obtained. In addition, the OCT measurement of the cornea is performed in a state where the apex of the cornea (first portion) substantially coincides with the coherence gate, and the fundus center (second portion) substantially coincides with the coherence gate. It is assumed that OCT measurement of the fundus oculi Ef is performed in a state in which it is in a state (a case where this is not the case will be described in operation example 2 described later).

  Under these assumptions, the distance calculation unit 234 calculates the absolute value of the difference between the first measurement optical path length L1 indicated by the first optical path length information and the second measurement optical path length L2 indicated by the second optical path length information. ) | L1-L2 | is calculated. This calculation process includes, for example, a process of subtracting the smaller one of the two measurement optical path lengths or a process of calculating the absolute value after calculating the difference between the two measurement optical path lengths. The value of the difference obtained in this way becomes the target intraocular distance (ocular axis length).

  In this example, the measurement optical path length is changed by moving the corner cube of the optical path length changing unit 41. Therefore, the information indicated by the first and second optical path length information may be the position information of the corner cube. This position information is acquired based on, for example, control content (for example, the number of control pulses) by the control unit 210, or is detected by a position sensor. The distance calculation unit 234 divides a value twice the difference between the position P1 of the corner cube indicated by the first optical path length information and the position P2 indicated by the second optical path length information by the refractive index n in the eye. The calculated value “2 × | P1−P2 | ÷ n” is calculated as the intraocular distance (ocular length). Note that the value of the refractive index n is known and is a standard value (for example, a value of a Gullstrand model eye) or an actual measurement value of the eye E to be examined.

(Operation example 2)
Refer to the flowcharts shown in FIGS. 7A and 7B. Reference is also made to FIGS. 7C and 7D. This example shows an example of the operation when auto-Z is applied.

(S11: Start of anterior segment imaging)
First, refer to FIG. 7A. This step is executed, for example, in the same manner as Step S1 of Operation Example 1.

(S12: Alignment)
This step is executed, for example, in the same manner as step S2 of the operation example 1.

(S13: Auto Z targeting the corneal apex)
After completing the alignment in step S12, the control unit 210 executes auto-Z for matching the corneal apex to the coherence gate. Auto Z is executed as described above. The control unit 210 causes the storage unit 212 to store information indicating success or failure of the auto-Z.

  When auto Z fails, the position of the image within the frame of the OCT image can be adjusted by, for example, manual operation. In the present example, an image corresponding to the corneal apex may be included in the frame.

(S14: OCT measurement of cornea)
This step is executed, for example, in the same manner as step S3 in the first operation example.

(S15: Storage of OCT data and anterior segment image)
This step is executed, for example, in the same manner as Step S4 of Operation Example 1.

(S16: Change of optical path length)
This step is executed, for example, in the same manner as step S5 of the first operation example.

(S17: Auto Z targeting the fundus center)
Subsequently, the control unit 210 executes auto Z for making the fundus center coincide with the coherence gate. Auto Z is executed as described above. The control unit 210 causes the storage unit 212 to store information indicating success or failure of the auto-Z.

  When auto Z fails, the position of the image within the frame of the OCT image can be adjusted by, for example, manual operation. In this example, an image corresponding to the fundus center may be included in the frame.

(S18: Was an anterior ocular segment image substantially the same as that obtained during cornea measurement?)
This step is executed, for example, in the same manner as Step S6 of Operation Example 1.

(S19: OCT measurement of the fundus)
This step is executed, for example, in the same manner as step S7 in the first operation example.

(S20: Storage of OCT data)
This step is executed, for example, in the same manner as the OCT data storage process in step S4 of the first operation example. Here, it transfers to FIG. 7B.

(S21: Was Auto-Z successful?)
The controller 210 can recognize the success or failure of each auto Z by referring to the information stored in step S13 and step S17. When both auto Zs are successful (S21: YES), the process proceeds to step S25. Conversely, if one or both of the auto Zs have failed (S21: NO), the process proceeds to step S22.

(S22: Calculation of optical path length difference)
When the auto Z in step S13 and / or step S17 is unsuccessful (S21: NO), the distance calculation unit 234 first performs the first optical path length information indicated by the first optical path length information in the same manner as in step S8 of operation example 1. The difference (absolute value) | L1−L2 | between the measured optical path length L1 and the second measured optical path length L2 indicated by the second optical path length information is calculated. In this calculation process, for example, a value that is twice the difference between the position of the corner cube of the optical path length changing unit 41 in step S14 and the position in step S19 is calculated.

(S23: Calculation of displacement with respect to coherence gate)
Next, the distance calculation unit 234 calculates the displacement of the corneal apex with respect to the coherence gate in the OCT measurement in step S14 and the displacement of the fundus center with respect to the coherence gate in the OCT measurement in step S19.

  Processing for calculating the displacement of the corneal apex will be described with reference to FIG. 7C. Here, the description will be made with reference to the OCT image, but the displacement is calculated based on the detection signal of the interference light obtained by the OCT measurement, or an arbitrary signal or image obtained by processing this detection signal. Is possible.

  FIG. 7C shows an OCT image (corneal OCT image) G1 generated based on the OCT measurement in step S14. The cornea OCT image G1 includes a pixel (corneal apex pixel) A1 at a position corresponding to the apex of the cornea. Further, in the frame (image range) of the corneal OCT image G1, it is assumed that the center position in the z direction corresponds to the coherence gate (denoted as coherence gate position C1). The position of the coherence gate in the frame is not limited to this, but the position is known in any case.

  First, the distance calculation unit 234 identifies the corneal vertex pixel A1 by analyzing the corneal OCT image G1. This analysis process includes, for example, a process for specifying a pixel group corresponding to the corneal surface (frontal cornea) based on the pixel value, and a pixel located in the most −z direction (upward in the frame) among the specified pixel group. And a process for specifying As another example, in this analysis process, pixels corresponding to the cornea are sequentially changed from the upper side to the lower side in pixel values of a pixel group on a line orthogonal to the z direction (a line extending in the left-right direction in the frame) in the corneal OCT image G1. The process includes identifying the first pixel having a pixel value corresponding to the cornea by comparing with the value. As yet another example, when OCT measurement is performed in a state of alignment, this analysis process is identified as a process for specifying a pixel group corresponding to the cornea surface (frontal cornea) based on the pixel value. And specifying a pixel located on a straight line that bisects the frame in the direction orthogonal to the z direction (the left-right direction of the frame) in the pixel group.

  Next, the distance calculation unit 234 calculates a distance D1 between the corneal apex pixel A1 specified in the preceding process and the coherence gate position C1. This calculation process includes, for example, a process for obtaining a perpendicular drawn from the corneal apex pixel A1 to the coherence gate position C1, a process for counting the number of pixels on the perpendicular, a number of pixels and a predetermined pixel interval (actual Processing corresponding to a distance in space). The process for obtaining a perpendicular line may include, for example, a process for obtaining a line segment extending in the z direction connecting the corneal apex pixel A1 and the coherence gate position C1. The distance D1 obtained as described above corresponds to the displacement of the corneal apex with respect to the coherence gate. As described above, this displacement includes a displacement amount and a displacement direction. In the example shown in FIG. 7C, the displacement amount is the distance D1, and the displacement direction is the −z direction (the direction away from the fundus oculi Ef).

  A process for calculating the displacement of the fundus center will be described with reference to FIG. 7D. This process may be similar to the calculation of the corneal apex displacement. In FIG. 7D, symbol G2 indicates an OCT image (fundus OCT image) generated based on the OCT measurement in step S19. Reference A2 indicates the fundus center, and reference C2 indicates the coherence gate position. Reference sign D2 indicates the displacement of the fundus center A2 with respect to the coherence gate position C2. In the example shown in FIG. 7D, the displacement amount is the distance D2, and the displacement direction is the + z direction (the direction away from the cornea).

(S24: Calculation of intraocular distance based on optical path length difference and image displacement)
The distance calculation unit 234 calculates the difference in optical path length (ΔL) calculated in step S22, the displacement of the corneal apex with respect to the coherence gate calculated in step S23 (ΔA1), and / or the displacement of the fundus center with respect to the coherence gate (ΔA2). Based on the above, the intraocular distance (axial length) is calculated.

  In the case shown in FIG. 7C and FIG. 7D, the displacement direction of the corneal apex is the direction away from the fundus oculi Ef, and the displacement direction of the fundus oculi center is the direction away from the cornea. Is added to the optical path length difference to obtain the intraocular distance (ocular length): ΔL + ΔA1 + ΔA2. Generally, when the displacement direction of one part is away from the other part, the displacement amount is added, and when the displacement direction of one part is a direction approaching the other part, the displacement amount is subtracted. Is done. The process in the case where the auto Z in step S13 and / or the auto Z in step S17 is unsuccessful (S21: NO) ends.

(S25: Calculation of intraocular distance based on optical path length)
On the other hand, when both auto-Z in step S13 and auto-Z in step S17 are successful (S21: YES), the distance calculation unit 234 performs intraocular distance (ocular length) in the same manner as in step S8 of operation example 1. Is calculated (S25).

(Operation example 3)
Reference is made to the flowchart shown in FIG. This example shows an example of the operation when auto-alignment using a reference image is performed.

(S31: Start of anterior segment imaging)
This step is executed, for example, in the same manner as Step S1 of Operation Example 1.

(S32: Alignment)
This step is executed, for example, in the same manner as step S2 of the operation example 1.

(S33: OCT measurement of cornea)
This step is executed, for example, in the same manner as step S3 in the first operation example.

(S34: Storage of OCT data and anterior segment image)
This step is executed, for example, in the same manner as Step S4 of Operation Example 1. The anterior ocular segment image stored here is used for auto-alignment in step S36.

(S35: Change of optical path length)
This step is executed, for example, in the same manner as step S5 of the first operation example.

(S36: Auto alignment)
The control unit 210 reads the anterior segment image stored in step S34 from the storage unit 212. The control unit 210 (and the data processing unit 230) performs auto alignment using the anterior segment image as a reference image. This auto-alignment includes, for example, a process for calculating the displacement of the frame with respect to the reference image for each frame (anterior eye image) sequentially input from the anterior eye camera 300A and / or 300B, and the calculated displacement. And a process of moving the optical system so as to cancel.

  The processing for calculating the displacement of the frame with respect to the reference image includes known image processing for calculating the displacement between the two images. For example, any of feature point extraction, image difference, affine transformation, image correlation, and the like is performed. May contain.

  The process of moving the optical system is performed by the control unit 210 controlling the optical system driving unit 2A based on the calculation result of the frame displacement with respect to the reference image. Note that “cancel displacement” indicates that the optical system is moved by (−Δx, −Δy) when the displacement is (Δx, Δy). Thereby, the optical system is arranged at a position where an anterior ocular segment image substantially the same as the reference image is obtained. Since the living eye is randomly moved, the optical system can be made to follow the movement of the eye E (auto tracking) by repeatedly executing the alignment process as described above.

(S37: Was an anterior ocular segment image substantially the same as that obtained during cornea measurement?)
This step is executed, for example, in the same manner as Step S6 of Operation Example 1.

(S38: OCT measurement of the fundus)
This step is executed, for example, in the same manner as step S7 in the first operation example. Note that, at the start timing of OCT measurement of the fundus oculi Ef, the auto-alignment (auto-tracking) in step S36 may already be completed or may be continued.

(S39: Calculation of intraocular distance)
This step is executed, for example, in the same manner as step S8 of the operation example 1.

[effect]
The effect of the ophthalmologic apparatus according to this embodiment will be described.

  The ophthalmologic apparatus according to the embodiment includes an imaging unit, an optical system, a changing unit, a control unit, and a calculation unit (for example, a distance calculation unit 234).

  The imaging unit (for example, the anterior eye cameras 300A and 300B) images the eye to be examined from two or more different directions. The optical system (for example, the optical system shown in FIGS. 1 and 2) divides the light from the light source (for example, the light source unit 101) into measurement light and reference light, and returns the measurement light from the eye to be examined and the reference light. Interference light is detected. The changing unit (for example, the optical path length changing unit 41) changes the optical path length of the measurement light. Note that the changing unit may have a function of changing the optical path length of the reference light. The changing unit may be configured to be able to change both the optical path length of the measurement light and the optical path length of the reference light.

  The control unit (for example, the control unit 210 (and the data processing unit 230)), when the first optical path length is set by the changing unit, causes the imaging unit to perform imaging and the optical system first detection. . Further, when the second optical path length is set by the changing unit and the second image substantially the same as the first image acquired by the imaging is acquired by the imaging unit, the control unit, The second detection by the optical system is executed.

  In the above example, the first optical path length corresponds to the optical path length set to perform OCT measurement of the cornea. Imaging is equivalent to anterior segment imaging performed together with OCT measurement of the cornea. The first detection corresponds to OCT measurement of the cornea. The second optical path length corresponds to the optical path length set for performing OCT measurement of the fundus. The second detection corresponds to fundus OCT measurement. These are merely examples. For example, the first optical path length may be an optical path length for performing OCT measurement of the fundus or other part, and the second optical path length is OCT measurement of the cornea or other part. The optical path length for performing Moreover, the image acquired by the imaging unit is not limited to the anterior segment image, and may be an image of the fundus or other part.

  Based on the first optical path length and the second optical path length, the calculation unit includes a first part of the eye to be examined through which the measurement light has passed in the first detection, and a second part through which the measurement light has passed in the second detection. Find the distance to the part.

  In the above example, the axial length is obtained, but the present invention is not limited to this, and it is depicted in an arbitrary portion depicted in the OCT image based on the first detection and the OCT image based on the second detection. It may be a distance between any part. In calculating the distance between these two parts, if the relative displacement between these parts is only the displacement in the z direction, addition and / or subtraction is used. On the other hand, when the relative displacement between these parts includes displacement in the x direction and / or displacement in the y direction, trigonometry is used in addition to addition and / or subtraction. For example, the three-square theorem can be applied in the synthesis process of the displacement in the x direction and / or the displacement in the y direction and the displacement in the z direction.

  According to such an embodiment, it is possible to measure the intraocular distance without providing an optical configuration for forming two reference optical paths. Moreover, according to the ophthalmologic apparatus which concerns on embodiment, even if the position and direction of the eye to be examined change between the first detection and the second detection, the imaging performed together with the first detection (OCT measurement) Since the second detection (OCT measurement) is performed at the timing when the second image that is substantially the same as the first image obtained by the above is acquired, the displacement of the position of the eye to be examined, etc. This eliminates the disadvantage that the measurement accuracy of the intraocular distance is lowered. Therefore, according to the ophthalmologic apparatus according to the embodiment, it is possible to measure the intraocular distance with high accuracy without increasing the size and complexity of the apparatus.

  The ophthalmologic apparatus according to the embodiment may be configured to acquire a time-series image by the imaging unit when the second optical path length is set. Furthermore, the control unit may include a specifying unit that specifies the second image by comparing still images sequentially acquired as time-series images with the first image. In addition, the control unit may be configured to execute the second detection in response to the second image specified by the specifying unit.

  According to this configuration, it is possible to specify the second image, that is, to detect the timing at which an image substantially the same as the first image is acquired. In addition, it is considered that the measurement accuracy is further improved by setting a time-series image capturing interval (for example, a frame interval of moving images) to be small.

  When the first part and the second part each correspond to a coherence gate, the calculation unit according to the embodiment calculates the difference between the first optical path length and the second optical path length as the first part. It may be configured to calculate the distance between the first part and the second part.

  On the other hand, the calculation unit according to the embodiment may be configured to execute the following process when at least one of the first part and the second part corresponds to a position away from the coherence gate: First The difference between the optical path length and the second optical path length is calculated; the displacement between the position away from the coherence gate (the position of the first part, the position of the second part) and the coherence gate is calculated. A distance between the first part and the second part is calculated based on the difference and the displacement.

  According to the processing performed with reference to such a coherence gate, the distance between the first part and the second part can be obtained with high accuracy.

  The ophthalmologic apparatus according to the embodiment may have a moving mechanism that moves the optical system. In this case, it is possible to apply the following configuration: the photographing unit acquires a time-series image; the control unit between the still image and the first image sequentially acquired as the time-series image. The control unit controls the moving mechanism so as to cancel the calculated displacement; while the control unit performs the movement control or after the movement control, a second detection ( OCT measurement) is executed.

  According to this configuration, auto-alignment (auto-tracking) is performed so that a second image substantially identical to the first image acquired by imaging performed together with the first detection (OCT measurement) is obtained. It is possible to execute.

  The control part which concerns on embodiment can perform the process for arrange | positioning a 1st site | part to a coherence gate based on the detection result by 1st detection. In addition to or instead of this, the control unit according to the embodiment can execute a process for placing the second part on the coherence gate based on the detection result of the second detection. Such processing corresponds to auto Z in the above example.

  According to this structure, the 1st site | part and / or 2nd site | part referred in distance measurement can be arrange | positioned to a coherence gate. The coherence gate is the position where the interference sensitivity is maximized, and the image drawn there has a high definition. Therefore, a high-definition image of the first part and / or the second part can be obtained. Thereby, the further improvement of the accuracy of distance measurement can be aimed at. Even if the first part and / or the second part do not completely coincide with the coherence gate, the function (auto Z) can be performed by arranging the first and / or second part in the vicinity thereof. The accuracy is improved as compared with the case of not having it.

<Second Embodiment>
In the first embodiment, control is performed so that substantially the same captured image is obtained both when the first optical path length is set for the optical system and when the second optical path length is set. Thus, the configuration for obtaining the distance (for example, the axial length) between the first part (for example, the corneal apex) and the second part (for example, the fundus center) of the eye to be examined has been described.

  On the other hand, in the second embodiment, the first photographing and the first detection are performed in a state where the first optical path length is set without performing control for acquiring substantially the same photographed image. Further, after executing the second imaging and the second detection in a state where the second optical path length is set, the distance between the first part and the second part of the eye to be examined is determined. Ask. In the distance calculation processing in this embodiment, in addition to the first optical path length and the second optical path length, the first and second images acquired by the first and second imaging are also referred to.

[Constitution]
The ophthalmologic apparatus according to this embodiment has the same hardware configuration as that of the first embodiment (see FIGS. 1, 2, 4A, and 4B). In addition, since the ophthalmologic apparatus of this embodiment does not need to execute control for acquiring substantially the same captured image, the configuration for the control may not be provided. A configuration example of a control system of the ophthalmologic apparatus according to this embodiment is shown in FIG. This configuration includes components excluding the image specifying unit 233 among the components shown in FIG. 3 of the first embodiment.

[Operation]
The operation of the ophthalmologic apparatus according to this embodiment will be described. An example of the operation of the ophthalmologic apparatus is shown in FIG. Note that the auto Z and / or auto alignment (auto tracking) described in the first embodiment can be applied. In addition, it is assumed that patient registration and setting of examination conditions have already been performed.

(S51: Alignment)
This step is executed, for example, in the same manner as Step S2 of Operation Example 1 of the first embodiment.

(S52a: Anterior segment imaging)
In step S52a, the anterior segment Ea is photographed using the anterior segment cameras 300A and 300B. The acquired captured image may be a still image or a time-series image (moving image or the like).

  Note that the order of step S52a and step S52b is arbitrary. These steps may be performed in parallel. For example, as in the first embodiment, acquisition of a time-series image of the anterior segment Ea is started before alignment in step S51, and OCT measurement in step S52b is performed while performing anterior segment imaging after alignment. It can be configured as follows. The difference in timing between step S52a and step S52b is desirably small enough not to be affected by eye movement. For example, this timing difference may be zero (ie, these steps are performed simultaneously).

(S52b: OCT measurement of cornea)
This step is executed, for example, in the same manner as step S3 of the operation example 1 of the first embodiment.

(S53: Storage of anterior segment image and OCT data)
This step is executed, for example, in the same manner as step S4 of the operation example 1 of the first embodiment.

(S54: Change of optical path length)
This step is executed, for example, in the same manner as Step S5 of Operation Example 1 of the first embodiment.

(S55a: Anterior segment imaging)
This step is executed in the same manner as step S52a, for example.

(S55b: OCT measurement of the fundus)
This step is executed, for example, in the same manner as step S7 of the operation example 1 of the first embodiment.

(S56: Storage of anterior segment image and OCT data)
This step is executed, for example, in the same manner as step S4 of the operation example 1 of the first embodiment.

(S57: Calculation of intraocular distance)
The controller 210 calculates the intraocular distance (ocular length) based on the anterior segment image and OCT data stored in step S53 and the anterior segment image and OCT data stored in step S56.

  When each of the end portions of the line segment corresponding to the intraocular distance (the corneal apex and the fundus center in the case of the axial length) exists at a position in the frame corresponding to the coherence gate, the distance calculation unit 234, for example, The following processing is executed: (1) The displacement between the anterior segment image (first image) stored in step S53 and the anterior segment image (second image) stored in step S56 is calculated. (2) The measurement optical path length (first optical path length) included in the OCT data stored in step S53 and the measurement optical path length (second optical path length) included in the OCT data stored in step S56. A difference is calculated; (3) A target intraocular distance is calculated based on the displacement calculated in (1) and the difference calculated in (2).

  The determination as to whether or not the end of the line segment exists at a position corresponding to the coherence gate is performed, for example, in the same manner as in the first embodiment.

  The image processing (1) may be the same as the comparison processing executed by the image specifying unit 233 of the first embodiment, for example. In this image processing, for example, displacement between two anterior segment images is obtained using any one of image correlation, feature point extraction, image difference, affine transformation, and the like. The displacement obtained by this image processing includes at least a displacement in a direction orthogonal to the z direction (xy direction), and may include a displacement in the z direction.

  The calculation process of (2) may be the same as the process executed by the distance calculation unit 234 of the first embodiment, for example. The difference obtained by this calculation process corresponds to the displacement in the z direction with respect to the two parts of the eye E to be examined.

  The calculation process of (3) is performed by, for example, the three-square theorem using the displacement in the xy direction obtained by the image process of (1) and the displacement (difference) in the z direction obtained by the calculation process of (2). This includes processing to synthesize using. Thereby, the intraocular distance corresponding to the three-dimensional displacement of the two parts of the eye E is acquired. In addition, when the displacement in the z direction is also obtained in the image processing of (1), the composition processing is executed by adding the displacement in the z direction.

  When one or both of the end portions of the line segment corresponding to the intraocular distance (the corneal vertex and the fundus center in the case of the axial length) do not exist at the position in the frame corresponding to the coherence gate, the distance calculation unit 234 For example, the following processing is executed: (1) Displacement between the anterior ocular segment image (first image) stored in step S53 and the anterior ocular segment image (second image) stored in step S56 (First displacement) is calculated; (2) for each part of the eye E (part corresponding to the above-mentioned end) existing at a position away from the coherence gate, between the position of this part and the coherence gate (3) the measurement optical path length (first optical path length) included in the OCT data stored in step S53 and the OCT data stored in step S56. The difference between the measured optical path length (second optical path length) to be measured; (4) the first displacement calculated in (1), the second displacement calculated in (2), and (3) The target intraocular distance is calculated based on the difference calculated in step (1).

  The image processing of (1) and the calculation processing of (3) may be the same as the case where both parts exist at a position corresponding to the coherence gate. Note that the first displacement obtained by the image processing of (1) includes at least a displacement in a direction (xy direction) orthogonal to the z direction, and may include a displacement in the z direction. Further, the difference obtained by the calculation process of (3) corresponds to the displacement in the z direction with respect to the two parts of the eye E.

  The calculation process of (2) includes, for example, a process of specifying a pixel corresponding to a target part of the eye E by analyzing an OCT image and a distance between the specified pixel and a pixel group corresponding to a coherence gate. The process of calculating. The second displacement obtained by this calculation process is a displacement in the z direction.

  The calculation process of (4) is, for example, the displacement in the z direction (second displacement) obtained by the calculation process of (2) and the displacement (difference) in the z direction obtained by the calculation process of (3). The process of calculating the sum or difference, the value of the sum or difference in the z direction, and the displacement in the xy direction (first displacement) obtained by the image processing in (1), for example, the square theorem And processing to synthesize. Thereby, the intraocular distance corresponding to the three-dimensional displacement of the two parts of the eye E is acquired.

  The ophthalmologic apparatus according to this embodiment may be able to execute the same auto alignment and / or auto Z as in the first embodiment. Auto-alignment is performed, for example, by moving the optical system before step S55a so that an anterior segment image substantially the same as the anterior segment image stored in step S53 is obtained. In addition, in the auto Z, for example, before the step S52a and / or before the step S55a, the measurement optical path and the reference optical path are arranged so that the target site of the eye E (for example, the apex of the cornea, the fundus center, etc.) is arranged on the coherence gate. By changing the optical path length difference between

[effect]
The effect of the ophthalmologic apparatus according to this embodiment will be described.

  The ophthalmologic apparatus according to the embodiment includes an imaging unit, an optical system, a changing unit, a control unit, and a calculation unit (for example, a distance calculation unit 234).

  The imaging unit (for example, the anterior eye cameras 300A and 300B) images the eye to be examined from two or more different directions. The optical system (for example, the optical system shown in FIGS. 1 and 2) divides the light from the light source (for example, the light source unit 101) into measurement light and reference light, and returns the measurement light from the eye to be examined and the reference light. Interference light is detected. The changing unit (for example, the optical path length changing unit 41) changes the optical path length of the measurement light. Note that the changing unit may have a function of changing the optical path length of the reference light. The changing unit may be configured to be able to change both the optical path length of the measurement light and the optical path length of the reference light.

  When the first optical path length is set by the changing unit, the control unit (for example, the control unit 210 (and the data processing unit 230)) performs first imaging by the imaging unit and first detection by the optical system. Is executed. Furthermore, the control unit causes the second imaging by the imaging unit and the second detection by the optical system to be executed when the second optical path length is set by the changing unit.

  The computing unit is configured to detect the first image acquired by the first imaging, the second image acquired by the second imaging, the first optical path length, and the second optical path length. A distance between the first part and the second part of the optometry is obtained. The first part and the second part are included in a range (scan range) through which the measurement light passes in the first detection and the second detection, respectively.

  According to such an embodiment, it is possible to measure the intraocular distance without providing an optical configuration for forming two reference optical paths. Moreover, according to the ophthalmologic apparatus which concerns on embodiment, even if the position and direction of a to-be-tested eye change between 1st detection and 2nd detection, the image by the 1st imaging | photography performed with 1st detection The displacement of the eye to be examined can be detected based on the (first image) and the image (second image) obtained by the second imaging performed together with the second detection. The ophthalmologic apparatus can determine the intraocular distance in consideration of the detected displacement. With such a configuration, the disadvantage that the measurement accuracy of the intraocular distance is reduced due to the shift of the position of the eye to be examined is solved. Therefore, according to the ophthalmologic apparatus according to the embodiment, the intraocular distance can be measured with high accuracy without increasing the size and complexity of the apparatus.

  The calculation unit according to the embodiment may be configured to perform the following processing when each of the first part and the second part corresponds to a coherence gate: the first image and the second image A difference between the first optical path length and the second optical path length is calculated; based on the displacement and the difference, a distance between the first part and the second part May be configured to calculate.

  On the other hand, the calculation unit according to the embodiment may be configured to execute the following process when at least one of the first part and the second part corresponds to a position away from the coherence gate: First A first displacement between the second image and the second image; a second distance between the coherence gate and a position away from the coherence gate (position of the first part, position of the second part) Calculating a displacement; calculating a difference between the first optical path length and the second optical path length; based on the first displacement, the second displacement, and the difference, the first portion and the second portion; Calculate the distance between them.

  According to the processing performed with reference to such a coherence gate, the distance between the first part and the second part can be obtained with high accuracy.

  The ophthalmologic apparatus according to the embodiment may have a moving mechanism that moves the optical system. In this case, it is possible to apply the following configuration: the photographing unit acquires a time-series image; the control unit between the still image and the first image sequentially acquired as the time-series image. The control unit controls the moving mechanism so as to cancel the calculated displacement; while the control unit performs the movement control or after the movement control, a second detection ( OCT measurement) is executed.

  According to this configuration, auto-alignment (auto-tracking) is performed so that a second image substantially identical to the first image acquired by imaging performed together with the first detection (OCT measurement) is obtained. It is possible to execute.

  The control part which concerns on embodiment can perform the process for arrange | positioning a 1st site | part to a coherence gate based on the detection result by 1st detection. In addition to or instead of this, the control unit according to the embodiment can execute a process for placing the second part on the coherence gate based on the detection result of the second detection. Such processing corresponds to auto Z in the above example.

  According to this configuration, a high-definition image of the first part and / or the second part can be obtained. Thereby, the further improvement of the accuracy of distance measurement can be aimed at. Even if the first part and / or the second part do not completely coincide with the coherence gate, the function (auto Z) can be performed by arranging the first and / or second part in the vicinity thereof. The accuracy is improved as compared with the case of not having it.

<Modification>
The embodiment described above is only an example. A person who intends to implement the present invention can make arbitrary modifications (omission, replacement, addition, etc.) within the scope of the present invention.

  In the above embodiment, the measurement optical path length is changed by changing the position of the optical path length changing unit 41, but the reference optical path length may be changeable. The configuration for changing the reference optical path length includes, for example, a reflection mirror (reference mirror) disposed in the optical path of the reference light, and a drive mechanism that moves the reference mirror in the traveling direction of the reference light.

  The technology described in the embodiment can be applied to a medical field other than ophthalmology or a field other than medical care. The technology according to the embodiment is particularly effective when the object is accompanied by movement (movement, deformation, etc.). For example, the technique can be applied to measurement of the heart and digestive organs, measurement of animal tissues, and the like.

  A computer program for realizing the above embodiment 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.

DESCRIPTION OF SYMBOLS 1 Ophthalmology apparatus 2 Fundus camera unit 2A Optical system drive part 100 OCT unit 200 Operation control unit 210 Control part 220 Image formation part 230 Data processing part 231 Analysis part 232 Image determination part 233 Image specification part 234 Distance calculation part 241 Display part 242 Operation Part 300, 300A, 300B anterior eye camera E eye Ea anterior eye part Ef fundus

Claims (4)

An imaging unit for imaging the eye to be examined from two or more different directions;
An optical system that divides light from the light source into measurement light and reference light, and detects interference light between the return light of the measurement light from the eye to be examined and the reference light;
A changing unit for changing the optical path length of the measurement light and / or the reference light;
When the first optical path length is set by the changing unit, the first imaging by the imaging unit and the first detection by the optical system are executed, and further the second optical path length is set. A control unit that sometimes performs second imaging by the imaging unit and second detection by the optical system;
Based on the first image acquired by the first imaging, the second image acquired by the second imaging, the first optical path length, and the second optical path length, the A calculation unit that obtains a distance between the first part of the eye to be examined through which the measurement light has passed in the first detection and the second part through which the measurement light has passed in the second detection;
When each of the first part and the second part corresponds to a coherence gate, the arithmetic unit is
Calculating a displacement between the first image and the second image;
Calculating the difference between the first optical path length and the second optical path length;
The ophthalmologic apparatus, wherein the distance is calculated based on the displacement and the difference. An imaging unit for imaging the eye to be examined from two or more different directions;
An optical system that divides light from the light source into measurement light and reference light, and detects interference light between the return light of the measurement light from the eye to be examined and the reference light;
A changing unit for changing the optical path length of the measurement light and / or the reference light;
When the first optical path length is set by the changing unit, the first imaging by the imaging unit and the first detection by the optical system are executed, and further the second optical path length is set. A control unit that sometimes performs second imaging by the imaging unit and second detection by the optical system;
Based on the first image acquired by the first imaging, the second image acquired by the second imaging, the first optical path length, and the second optical path length, the A calculation unit that obtains a distance between the first part of the eye to be examined through which the measurement light has passed in the first detection and the second part through which the measurement light has passed in the second detection;
When at least one of the first part and the second part corresponds to a position away from the coherence gate, the arithmetic unit is
Calculating a first displacement between the first image and the second image;
Calculating a second displacement between the position away from the coherence gate and the coherence gate;
Calculating the difference between the first optical path length and the second optical path length;
The ophthalmic apparatus characterized in that the distance is calculated based on the first displacement, the second displacement, and the difference. A moving mechanism for moving the optical system;
The photographing unit can acquire a time-series image,
The controller is
Calculating a displacement between the still image sequentially acquired as the time-series image and the first image;
Controlling the moving mechanism to cancel the calculated displacement;
The ophthalmologic apparatus according to claim 1, wherein the second detection is performed by the optical system while performing the control or after the control. The controller is configured to place the first part on a coherence gate based on the detection result of the first detection, and to change the second part based on the detection result of the second detection. The ophthalmologic apparatus according to any one of claims 1 to 3, wherein one or both of the processes for arranging the coherence gates is performed.

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