JP2018023819A - Ophthalmological observation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ophthalmological observation device which can achieve a new utilization method of a front cross-sectional image acquired by optical coherence tomography.SOLUTION: In an ophthalmological observation device, an optical system performs OCT, a three-dimensional image formation unit 231 successively acquires three-dimensional images of an eye to be examined on the basis of the data successively acquired by the optical system by repeatedly performing the OCT to a three-dimensional region of the eye to be examined, a cross-sectional image formation unit 232 successively forms front cross-sectional images on the basis of the three-dimensional images successively acquired by the three-dimensional image acquisition unit, a display control unit 2111 displays the front cross-sectional images successively formed by the cross-sectional image formation unit on display means as a moving image and displays information indicating the cross sections of the front cross-sectional images, and a measurement control unit 2112 causes the optical system to execute the OCT to the cross section position designated via operation means to the front cross-sectional images displayed on the display means.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an ophthalmologic observation apparatus that acquires an image of an eye to be examined using optical coherence tomography (OCT).

  In recent years, OCT that forms an image representing the surface form or internal form of an object to be measured using a light beam from a laser light source or the like has attracted attention. Since OCT has no invasiveness to the human body like X-ray CT, it is expected to be applied particularly in the medical field and the biological field. For example, in the field of ophthalmology, devices for imaging the retina, choroid, and cornea have been put into practical use, and their application has expanded to imaging the vitreous body.

  Patent Document 1 discloses an apparatus using a so-called “Fourier Domain OCT (Fourier Domain OCT)” technique. That is, this apparatus irradiates the object to be measured with a beam of low coherence light, superimposes the reflected light and the reference light to generate interference light, acquires the spectral intensity distribution of the interference light, and performs Fourier transform. By performing the conversion, the form of the object to be measured in the depth direction (z direction) is imaged. Further, this apparatus includes a galvanometer mirror that scans a light beam (measurement light) in one direction (x direction) orthogonal to the z direction, thereby forming an image of a desired measurement target region of the object to be measured. It has become. An image formed by this apparatus is a two-dimensional cross-sectional image in the depth direction (z direction) along the scanning direction (x direction) of the light beam. This technique is particularly referred to as a spectral domain.

  Patent Document 2 describes a technique for forming a three-dimensional image from a plurality of two-dimensional cross-sectional images obtained using OCT. Further, a technique for forming a two-dimensional image of a cross section perpendicular to the two-dimensional cross-sectional image (that is, an image on the xy plane at a predetermined z coordinate value) based on the three-dimensional image is known. This two-dimensional image is called a front sectional image, a horizontal sectional image, an en-face image, a C sectional image, a C scan image, or the like.

  Patent Documents 3 and 4 disclose other types of OCT apparatuses. In Patent Document 3, the wavelength of light irradiated to a measured object is scanned (wavelength sweep), and interference intensity obtained by superimposing reflected light of each wavelength and reference light is detected to detect spectral intensity distribution. And an OCT apparatus for imaging the form of an object to be measured by performing Fourier transform on the obtained image. Such an OCT apparatus is called a swept source type. The swept source type is a kind of Fourier domain type.

  In Patent Document 4, the measurement light having a predetermined beam diameter is irradiated onto the object to be measured, and the component of the interference light obtained by superimposing the reflected light and the reference light is analyzed. An OCT apparatus that forms an image of an object to be measured in a cross section orthogonal to the traveling direction is described. Such an OCT apparatus is called a full-field type or an unfaced type.

  Patent Document 5 discloses a configuration in which OCT is applied to the ophthalmic field. Prior to the application of OCT, a fundus camera, a slit lamp, an SLO (Scanning Laser Ophthalmoscope), or the like was used as an apparatus for observing the eye to be examined (for example, Patent Document 6, Patent Document 7, Patent Document). 8). A fundus camera is an apparatus that images the fundus by illuminating the subject's eye with illumination light and detecting return light from the fundus. A slit lamp is a device that acquires an image of a cross-section of the cornea by cutting off a light section of the cornea using slit light. The SLO is an apparatus that images the fundus surface by scanning the fundus with laser light and detecting the reflected light with a highly sensitive element such as a photomultiplier tube.

  An apparatus using OCT has an advantage over a fundus camera or the like in that a high-definition image can be acquired, and further, a cross-sectional image or a three-dimensional image can be acquired.

  As described above, an apparatus using OCT can be applied to observation of various parts of an eye to be examined, and can acquire high-definition images, and thus has been applied to diagnosis of various ophthalmic diseases.

  OCT devices in the field of ophthalmology generally incorporate functions such as alignment (positioning of the optical system with respect to the eye to be examined), focusing (setting of the imaging depth), and tracking (following movement of the optical system with respect to movement of the eye to be examined). ing. In addition, a function for arbitrarily designating a target region for imaging is also provided. For example, a cross section is designated with reference to a front image representing the surface form of the fundus.

JP 11-325849 A JP 2007-225349 A JP 2007-24677 A JP 2006-153838 A JP 2008-73099 A JP-A-9-276232 JP 2008-259544 A JP 2009-11811 A

  An object of the present invention is to provide an ophthalmologic observation apparatus capable of realizing a novel method of using a front cross-sectional image acquired by OCT.

In order to achieve the above object, an invention described in claim 1 includes an optical system, a three-dimensional image acquisition unit, a cross-sectional image forming unit, a display control unit, and a measurement control unit. The optical system performs optical coherence tomography. The three-dimensional image acquisition unit sequentially acquires a three-dimensional image of the eye to be inspected based on data sequentially acquired by the optical system by repeatedly performing optical coherence tomography on the three-dimensional region of the eye to be inspected. The cross-sectional image forming unit sequentially forms front cross-sectional images based on the three-dimensional images sequentially acquired by the three-dimensional image acquisition unit. The display control unit causes the display unit to display a moving image of the front cross-sectional image sequentially formed by the cross-sectional image forming unit. Further, the display control unit displays information indicating the cross section of the front cross-sectional image formed by the cross-sectional image forming unit together with the front cross-sectional image. The measurement control unit causes the optical system to execute optical coherence tomography with respect to the cross-sectional position designated via the operation unit with respect to the front cross-sectional image displayed on the display unit.
The invention according to claim 2 is the ophthalmologic observation apparatus according to claim 1, wherein the cross-sectional image forming unit has a depth based on the three-dimensional images sequentially acquired by the three-dimensional image acquisition unit. Two or more front cross-sectional images corresponding to two or more cross-sections at different positions are formed, and the display control unit displays two or more front cross-sectional images as moving images and displays information indicating two or more cross-sections. It is characterized by.

  According to the present invention, an ophthalmologic observation apparatus capable of realizing a novel method of using a front cross-sectional image acquired by OCT is provided.

It is a schematic diagram showing an example of composition of an ophthalmology observation device concerning an embodiment. It is a schematic diagram showing an example of composition of an ophthalmology observation device concerning an embodiment. It is a schematic diagram showing an example of composition of an ophthalmology observation device concerning an embodiment. It is a flowchart showing the operation example of the ophthalmic observation apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the ophthalmic observation apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the ophthalmic observation apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the ophthalmic observation apparatus which concerns on embodiment. It is a schematic diagram showing an example of composition of an ophthalmology observation device concerning an embodiment. It is a flowchart showing the operation example of the ophthalmic observation apparatus which concerns on embodiment. It is a schematic diagram showing an example of composition of an ophthalmology observation device concerning an embodiment. It is a flowchart showing the operation example of the ophthalmic observation apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the ophthalmic observation apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the ophthalmic observation apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the ophthalmic observation apparatus which concerns on embodiment.

  An example of an embodiment of an ophthalmologic observation apparatus according to the present invention will be described in detail with reference to the drawings. The ophthalmologic observation apparatus according to the embodiment forms a two-dimensional cross-sectional image or a three-dimensional image of the fundus using OCT. In this specification, an image acquired by OCT may be referred to as an OCT image. In addition, a measurement operation for forming an OCT image may be referred to as 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 configuration to which Fourier domain type OCT is applied will be described in detail. The ophthalmologic observation apparatus according to the embodiment is configured to be able to acquire both a fundus OCT image and a fundus image using, for example, a spectral domain OCT technique. The OCT method is not limited to the spectral domain, and may be a swept source type, for example. In the embodiment, a multi-function apparatus in which an OCT apparatus and a fundus camera are combined will be described in detail. However, an apparatus that captures a subject's eye and obtains a front image is not limited to a fundus camera. It may be a lamp, an ophthalmic surgical microscope, or the like. In addition, the configuration of the ophthalmic observation apparatus according to the embodiment is not limited to the multifunction peripheral, and may be a single OCT apparatus.

  Several embodiments will be described below, but two or more of these embodiments can be arbitrarily combined.

<First Embodiment>
[Constitution]
As shown in FIGS. 1 and 2, the ophthalmologic observation 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. The captured image is, 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. Further, 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 imaging optical system 30 guides the return light of the illumination light from the fundus oculi Ef to the imaging devices (CCD image sensors (sometimes simply referred to as CCD) 35 and 38). The imaging optical system 30 guides the measurement light from the OCT unit 100 to the fundus oculi Ef and guides the return light of the measurement light from the fundus oculi Ef to the OCT unit 100.

  The observation light source 11 of the illumination optical system 10 is constituted by a halogen lamp, for example. 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. An LED (Light Emitting Diode) can also be used as the observation light source.

  The return light of the observation illumination light from the fundus oculi Ef is refracted by the objective lens 22, passes through the dichroic mirror 46, passes through the hole formed in the central region of the aperture mirror 21, passes through the dichroic mirror 55, The light is reflected by the mirror 32 via the focusing lens 31. Further, the return light passes through the half mirror 39A, is reflected by the dichroic mirror 33, and forms an image on the light receiving surface of the CCD image sensor 35 by the condenser lens. The CCD image sensor 35 detects return light at a predetermined rate, for example. The display device 3 displays an image (observation image) based on the return light detected by the CCD image sensor 35. In addition, when the focus of the imaging optical system 30 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, 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 return light of the photographing illumination light from the fundus oculi Ef is guided to the dichroic mirror 33 through the same path as that of the observation illumination light, passes through the dichroic mirror 33, is reflected by the mirror 36, and is reflected by the condenser lens 37. An image is formed on the light receiving surface of the sensor 38. An image (captured image) based on the return light detected by the CCD image sensor 38 is displayed on the display device 3. 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. It is also possible to use an LED as a photographing light source.

  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, as in a conventional fundus camera, a position for acquiring an image centered on the macular portion of the fundus oculi Ef (macular measurement fixation position), or the optic nerve head as the center There are a position for acquiring an image (a fixation position for papillary measurement), a position for acquiring a wide range image including the macula and the optic nerve head (a fixation position for wide-area measurement), and the like. 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).

  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 return light of the focus light from the fundus oculi Ef is detected by the CCD image sensor 35 through the same path as the corneal 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 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 (autofocus function), as in the conventional case. Further, focusing may be performed manually while visually checking the split index.

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

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

[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 fundus oculi Ef. This optical system has the same configuration as a conventional spectral domain type OCT apparatus. That is, this optical system divides the light from the light source (low coherence light) into reference light and measurement light, and generates interference light by causing the measurement light passing through the fundus oculi Ef and the reference light passing through the reference optical path to interfere with each other. The spectral component of the interference light is detected by a spectroscope. 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 capable of switching the output wavelength at high speed is provided in place of a low coherence light source, and a photodetector such as a balanced photodiode is provided as a spectrometer. It is provided instead of. In general, for the configuration of the OCT unit 100, a known technique according to the type of optical coherence tomography can be arbitrarily applied.

  The light source unit 101 outputs light L0 for OCT measurement. In this embodiment, since the spectral domain OCT is applied, broadband low-coherence light is used as the light L0. The light L0 includes, for example, a near-infrared wavelength band (about 800 nm to 900 nm) and has a temporal coherence length of about several tens of micrometers. Note that near-infrared light having a wavelength band that cannot be visually recognized by the human eye, for example, a center wavelength of about 1040 to 1060 nm, may be used as the 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 light L0 output from the light source unit 101 is guided to the fiber coupler 103 by the optical fiber 102 and split into the measurement light LM 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 LM 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 LM 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 LM is reflected by the dichroic mirror 46, refracted by the objective lens 22, and irradiated on the fundus oculi Ef. The measurement light LM is scattered (including reflection) at various depth positions of the fundus oculi Ef. The backscattered light (return light) of the measurement light LM from the fundus oculi Ef travels in the opposite 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 return light of the measurement light LM 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 and forms an OCT image of the fundus oculi Ef. 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 fundus oculi Ef on the display device 3.

  As the control of the fundus camera unit 2, the arithmetic control unit 200 controls the operation of the observation light source 11, the imaging light source 15 and the LEDs 51 and 61, the operation control of the LCD 39, the movement control of the focusing lenses 31 and 43, 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, 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 ophthalmic observation 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 observation apparatus 1 will be described with reference to FIG.

(Control part)
The control system of the ophthalmologic observation 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 is provided with a main control unit 211 and a storage unit 212.

(Main control unit)
The main control unit 211 performs the various controls described above. For example, the main control unit 211 controls the optical system driving unit 2A, the focusing driving unit 31A, the optical path length changing unit 41, the galvano scanner 42, and the OCT focusing driving unit 43A of the fundus camera unit 2. The main control unit 211 also controls the light source unit 101, the optical attenuator 105, the polarization adjuster 106, and the CCD 115 of the OCT unit 100.

  Under the control of the main controller 211, the optical system driver 2A moves the apparatus optical system (particularly, the optical system included in the fundus camera unit 2) three-dimensionally. This control is used in alignment and tracking. As described above, the tracking is a control for moving the apparatus optical system in accordance with the eye movement of the eye E. When tracking is performed, alignment and focusing are performed in advance. The tracking is a function of detecting the movement of the eye E in real time using an observation image, for example, and moving the apparatus optical system based on the detection result, thereby causing the position of the apparatus optical system to follow the eye movement. Thereby, a suitable positional relationship in which the alignment and focus are achieved is maintained. Note that the movement direction of the apparatus optical system by the optical system driving unit 2A is not limited to the x direction, the y direction, and the z direction, and may include, for example, a rotation direction around a predetermined axis, an elevation direction, and the like.

  Under the control of the main control unit 211, the focusing drive unit 31A moves the focusing lens 31 of the photographing optical system 30 in the optical axis direction. Thereby, the focal position of the photographing optical system 30 is changed.

  Under the control of the main control unit 211, the OCT focusing drive unit 43A moves the focusing lens 43 provided in the path of the measurement light LM in the optical axis direction. As a result, the focus position (beam waist position) of the measurement light LM is changed.

  The main control unit 211 performs a process of writing data to the storage unit 212 and a process of reading data from the storage unit 212.

  In this embodiment, the main control unit 211 includes a display control unit 2111 and a measurement control unit 2112. The display control unit 2111 executes control for causing the display unit 241 to display information. This control will be described later. The measurement control unit 2112 performs control related to OCT measurement. This control will be described later.

(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 observation apparatus 1.

(Image forming part)
The image forming unit 220 forms image data of a cross-sectional image of the fundus oculi Ef based on the detection signal input from the CCD image sensor 115. This process includes processes such as noise removal (noise reduction), filter processing, dispersion compensation, and FFT (Fast Fourier Transform) as in the conventional spectral domain type optical coherence tomography. In this embodiment, the image forming unit 220 forms a one-dimensional image (A line image) along the A line (line extending in the z direction) at each irradiation position of the measurement light LM. Furthermore, the image forming unit 220 forms a two-dimensional cross-sectional image (B-scan image) in which a plurality of A-line images corresponding to a plurality of irradiation positions arranged linearly or curvedly are arranged according to the arrangement. Also good. In the case of another type of OCT apparatus, the image forming unit 220 executes a known process corresponding to the type.

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

(Image processing unit)
The image 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 image processing unit 230 executes various correction processes such as image brightness correction. The image 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 image processing unit 230 includes a three-dimensional image forming unit 231 and a cross-sectional image forming unit 232.

(3D image forming unit)
The three-dimensional image forming unit 231 performs three-dimensional image processing for the fundus oculi Ef by performing known image processing such as processing for interpolating pixels between A-line images or interpolation processing for interpolating pixels between B-scan images. Form image data. The three-dimensional image data means image data in which pixel positions are defined by a three-dimensional coordinate system. As an example of 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. As an example of processing for displaying an image based on volume data, the image processing unit 230 performs rendering processing (volume rendering, MIP (Maximum Intensity Projection), etc.) on the volume data, and views the image from a specific line-of-sight direction. A pseudo three-dimensional image is formed.

  Another example of 3D image data is stack data. Stack data is image data obtained by three-dimensionally arranging a plurality of B scan images obtained along a plurality of scanning lines based on the positional relationship of the scanning lines. That is, the stack data is image data obtained by expressing a plurality of B-scan images originally defined by individual two-dimensional coordinate systems in one three-dimensional coordinate system (that is, embedding in one three-dimensional space). It is.

(Cross-section image forming part)
The cross-sectional image forming unit 232 forms a cross-sectional image based on the 3D image data formed by the 3D image forming unit 231. This cross-sectional image is an image representing a preset cross-section. This cross section is defined by an arbitrary position and orientation. This cross section may be flat or curved. In addition, a cross-sectional view when the posterior eye portion of the eye E to be examined is viewed from the front side (corneal side), for example, a cross-sectional view showing a cross-section in which (at least one) normal line coincides with the z direction, Sometimes called.

  For example, the cross-sectional image forming unit 232 selects a pixel (or voxel) positioned in a predetermined cross-section from pixels (or voxels) of the three-dimensional image data, thereby generating a two-dimensional cross-sectional image representing the cross-section. It may be formed. Note that when there is no pixel located in the cross section, such as when the above-described interpolation processing is not performed (that is, when stack data is used), the pixel closest to the cross section can be selected. Alternatively, a pixel value corresponding to the cross section may be obtained by executing an interpolation process (such as a weighted interpolation process) based on pixels adjacent to the cross section.

  In addition, the cross-sectional image forming unit 232 includes, for example, pixels (or a range representing a predetermined layer of the fundus oculi Ef) included in a preset range (for example, a range representing a predetermined layer of the fundus oculi Ef) among pixels (or voxels) of the three-dimensional image data. Voxel) may be selected and the selected three-dimensional region may be integrated in the z direction to form a two-dimensional cross-sectional image. If there is no pixel located in the cross section, the same processing as described above can be executed.

  The cross-sectional image formed by the cross-sectional image forming unit 232 need not be a two-dimensional cross-sectional image. For example, the cross-sectional image forming unit 232 forms a three-dimensional partial image by extracting pixels (or voxels) included in a preset three-dimensional region from pixels (or voxels) of the three-dimensional image data. Good. When displaying a three-dimensional partial image, the above-described rendering process is applied.

  The imaging range (cross section, three-dimensional area, etc.) is input to the cross-sectional image forming unit 232 in advance. The imaging range is set manually or automatically.

  When manually setting the imaging range, the user uses the user interface 240. For example, the main control unit 211 causes the display unit 241 to display a graphical user interface (GUI) for setting the imaging range. The user sets the imaging range by operating the GUI using the operation unit 242.

  As a specific example, the main control unit 211 can cause the display unit 241 to display a pseudo three-dimensional image or a B-scan image. The user uses the operation unit 242 to set the cross-sectional position for the displayed image. The image processing unit 230 performs processing for extending the set cross-sectional position to the entire three-dimensional image data. This process is performed, for example, by expanding the set cross-sectional position in a predetermined direction. For example, when setting a cross-section for acquiring a planar front cross-sectional image, the cross-sectional position set manually corresponds to the z-coordinate value (z = z0), so the image processing unit 230 determines that the plane z = z0. Is set as the target cross section. In this case, a pixel (or voxel) whose position information is (x = arbitrary, y = arbitrary, z = z0) is extracted from the three-dimensional image data, and a planar front surface based on the extracted pixel (or voxel). A cross-sectional image is formed.

  Another example of manual setting will be described. The main control unit 211 can present options for the part name (tissue name) of the eye E on the display unit 241. Examples of the presented site include the retina, choroid, sclera, retinal detachment site, lesion site, and treated site. In addition, as a sub-tissue of the retina, retinal pigment epithelium layer, photoreceptor layer, outer boundary membrane, outer granule layer, outer reticular layer, inner granule layer, inner reticular layer, ganglion cell layer, nerve fiber layer, inner boundary membrane, There are joints between inner and outer segments of photoreceptor cells. The user designates one or more of the displayed options. The mode of the designation operation is arbitrary, and includes, for example, an operation of inputting a check into a check box of a desired option. The image processing unit 230 identifies the pixel (or voxel) corresponding to the part designated by the user by analyzing the three-dimensional image data. This analysis process includes, for example, a known layer specifying process (segmentation). The cross-sectional image forming unit 232 forms a cross-sectional image based on the pixels (or voxels) specified by the analysis process.

  When the imaging range is automatically set, the main control unit 211 sets the imaging range based on a predetermined condition. Examples of this condition include a disease name and an imaging range applied in the past.

  When the disease name is included in the condition, information (corresponding information) in which the disease name is associated with the imaging range is stored in the storage unit 212 in advance. The main control unit 211 acquires a disease name with reference to the electronic medical record information of the patient, for example. Further, the main control unit 211 identifies the imaging range associated with the acquired disease name by referring to the correspondence information. The processing for obtaining pixels (or voxels) corresponding to the specified imaging range may be the same as the analysis processing in the case of manual setting.

  For example, when the imaging range applied in the past is included in the condition as in the case of follow-up imaging, information indicating the imaging range applied in the examination is stored in the electronic medical record information of the patient. Alternatively, the main control unit 211 causes the storage unit 212 to store the patient ID and the like of the patient in association with information indicating the applied imaging range. When a new examination is performed, the main control unit 211 reads information indicating the imaging range recorded in the electronic medical record information of the patient. Alternatively, the main control unit 211 receives information such as a patient ID and searches the storage unit 212 for information indicating the imaging range. The processing after the past imaging range is acquired may be the same as the analysis processing in the case of manual setting.

  In addition, when the type (that is, imaging range) of the acquired cross-sectional image is determined in advance, such as a medical examination or a clinical path, the image processing unit 230 executes the analysis processing described in the case of manual setting. The pixels (or voxels) located in the target cross section can be identified from the three-dimensional image data.

  The image processing unit 230 having the above functions includes, for example, a microprocessor, a RAM, a ROM, a hard disk drive, a 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 observation 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 GUI displayed on the display unit 241 and the operation unit 242.

[Scanning light and OCT image]
The scanning of the measurement light LM and the OCT image will be described.

  Examples of the scanning mode (scan pattern) of the measurement light LM by the ophthalmic observation apparatus 1 include a horizontal scan, a vertical scan, a cross scan, a radial scan, a circular scan, a concentric scan, and a spiral (spiral) scan. These scanning modes are selectively used in consideration of the observation site of the fundus (optic nerve head, macula, lesioned part, etc.), analysis target (such as retinal thickness), time required for scanning, scanning precision, and the like.

  In the horizontal scan, the measurement light LM is scanned in the horizontal direction (x direction). The horizontal scan includes a mode in which the measurement light LM is scanned along a plurality of horizontal scanning lines arranged in the vertical direction (y direction). In this aspect, it is possible to arbitrarily set the scanning line interval. Further, the above-described three-dimensional image can be formed by sufficiently narrowing the interval between adjacent scanning lines (three-dimensional scanning). The same applies to vertical scanning.

  In the cross scan, the measurement light LM is scanned along a cross-shaped trajectory formed by two linear trajectories (straight trajectories) orthogonal to each other. In the radiation scan, the measurement light LM is scanned along a radial trajectory composed of a plurality of linear trajectories arranged at a predetermined angle. The cross scan is an example of a radiation scan.

  In the circle scan, the measurement light LM is scanned along a circular locus. In the concentric scan, the measurement light LM is scanned along a plurality of circular trajectories arranged concentrically around a predetermined center position. A circle scan is an example of a concentric scan. In the spiral scan, the measurement light LM is scanned along a spiral (spiral) locus while gradually reducing (or increasing) the radius of rotation.

  Since the galvano scanner 42 is configured to scan the measurement light LM in directions orthogonal to each other, the measurement light LM can be scanned independently in the x direction and the y direction, respectively. Furthermore, by simultaneously controlling the directions of the two galvanometer mirrors included in the galvano scanner 42, it is possible to scan the measurement light LM along an arbitrary locus on the xy plane. Thereby, various scanning modes as described above can be realized.

  By scanning the measurement light LM in the above-described manner, a cross-sectional image on a plane stretched by the direction along the scanning line (scanning locus) and the fundus depth direction (z direction) can be acquired. In addition, the above-described three-dimensional image can be acquired particularly when the scanning line interval is narrow.

  The region on the fundus oculi Ef to be scanned with the measurement light LM as described above, that is, the region on the fundus oculi Ef to be subjected to OCT measurement may be referred to as a scanning region. The scanning area in the three-dimensional scan is a rectangular area in which a plurality of horizontal scans are arranged. The scanning area in the concentric scan is a disk-shaped area surrounded by the locus of the circular scan with the maximum diameter. In addition, the scanning area in the radial scan is a disk-shaped (or polygonal) area connecting both end positions of each scan line.

[Operation]
The operation of the ophthalmologic observation apparatus 1 will be described. FIG. 4 shows an example of the operation of the ophthalmologic observation apparatus 1. In this operation example, a case will be described in which a cross-sectional position to be subjected to the main measurement is designated based on a front cross-sectional image acquired by preliminary OCT measurement of the posterior segment of the eye E (for example, the fundus oculi Ef). In this operation example, alignment, focusing, and tracking are executed based on the observation image of the eye E. The case where one or more of these operations are executed based on the OCT image will be described later.

(S1: Start acquisition of near-infrared observation image)
First, the main control unit 211 starts lighting the observation light source 11. The observation illumination light output from the observation light source 11 becomes near infrared light by the visible cut filter 14. The observation illumination light is continuously applied to the fundus oculi Ef, and the return light is detected by the CCD image sensor 35 at a predetermined rate. The main control unit 211 causes the display unit 241 to display a moving image (near-infrared observation image) of the fundus oculi Ef based on a detection signal input from the CCD image sensor 35 at a predetermined rate. The near-infrared observation image is acquired in real time until the observation light source 11 is turned off, for example.

  The main control unit 211 projects a fixation target onto the eye E at a predetermined timing. The subject is instructed to stare at the fixation target. Further, the main control unit 211 projects the alignment index and the split index onto the fundus oculi Ef at a predetermined timing. Note that the projection timings of these indices may be the same or different. After the projection of these indices is started, the alignment index image and the split index image are reflected in the near-infrared observation image.

(S2: Perform alignment and focusing)
Next, alignment and focusing are performed. These processes are executed manually or automatically as in the conventional case.

  In the case of manual alignment, the user guides the pair of alignment index images to the position of the target mark while referring to the pair of alignment index images displayed on the display unit 241 and the mark indicating the predetermined target position. Then, the optical system of the apparatus is moved via the operation unit 242. The movement of the apparatus optical system is executed by the main control unit 211 receiving the operation signal from the operation unit 242 controlling the optical system driving unit 2A.

In the case of auto alignment, for example, the following processing is executed.
-Analyze the near-infrared observation image to determine the position of the pair of alignment index images.
A displacement between the position of the obtained pair of alignment index images and a predetermined target position is obtained.
The optical system drive unit 2A is controlled to move the apparatus optical system so that the obtained displacement is cancelled.

  In the case of manual focus, the user refers to the pair of split index images displayed on the display unit 241 so that the pair of split index images are arranged in a predetermined positional relationship (for example, arranged in a line). 2), the focusing lens 31 is moved via the operation unit 242. The movement of the focusing lens 31 is executed by the main control unit 211 receiving the operation signal from the operation unit 242 controlling the focusing drive unit 31A.

In the case of autofocus, for example, the following processing is executed.
-Analyze the near-infrared observation image to determine the position of the pair of split index images.
A displacement between the position of the obtained pair of split index images and a predetermined positional relationship is obtained.
The focus driving unit 31A is controlled to move the focusing lens 31 so that the obtained displacement is canceled.

(S3: Start tracking)
When the alignment and focusing are completed, the main control unit 211 starts a tracking operation similar to the conventional one. In tracking, for example, the following processing is repeatedly executed.
Analyzing the frame of the near-infrared observation image, and a characteristic region corresponding to a characteristic part of the eye E (for example, the center of the pupil in the anterior segment image and the center of the macular, nipple, or lesion in the fundus image) Find the position of.
The displacement between the position of the feature area obtained this time and the position of the feature area obtained in the previous process is obtained.
The optical system drive unit 2A is controlled to move the apparatus optical system so that the obtained displacement is cancelled.

(S4: Start live OCT measurement)
The main control unit 211 starts live OCT measurement by controlling the OCT unit 100 and the galvano scanner 42. Live OCT measurement refers to processing for acquiring an OCT moving image in real time by repeatedly performing OCT measurement with a predetermined scan pattern at a predetermined rate.

  In this operation example, a three-dimensional scan is applied as a scan pattern. The region of the eye E (fundus Ef) to be scanned is determined by the projection position of the fixation target and the contour shape and size of the scan pattern. These conditions are arbitrarily set. As described above, the fixation target projection position includes a macular measurement fixation position, a nipple measurement fixation position, a wide-range measurement fixation position, and the like.

(S5: Start displaying the live front sectional image)
The image forming unit 220 sequentially forms B scan images based on the detection signals input at a predetermined rate from the CCD image sensor 115 in the live OCT measurement in step S4. For example, the main control unit 211 sequentially sends a plurality of B scan images corresponding to one 3D scan to the 3D image forming unit 231.

  The three-dimensional image forming unit 231 forms three-dimensional image data corresponding to the three-dimensional scan based on a plurality of B scan images corresponding to one three-dimensional scan. The three-dimensional image data sequentially formed by the three-dimensional image forming unit 231 is sequentially sent to the cross-sectional image forming unit 232.

  The cross-sectional image forming unit 232 forms a front cross-sectional image in a preset cross section based on each three-dimensional image data formed by the three-dimensional image forming unit 231. This cross section is set for a tissue that a user particularly pays attention to, such as a photoreceptor inner / outer segment junction (IS / OS), a retinal pigment epithelium (RPE), and an inner limiting membrane (ILM, fundus surface). It's okay. The front sectional images sequentially formed by the sectional image forming unit 232 are sequentially sent to the display control unit 2111.

  The display control unit 2111 causes the display unit 241 to display the front cross-sectional images sequentially formed by the cross-sectional image forming unit 232 at a predetermined rate. Thereby, a live moving image representing the cross section is displayed. Since the tracking started in step S3 is continued, a front cross-sectional image of substantially the same region of the eye E is displayed as a moving image.

  In this step, the adjustment of the depth range in which the OCT measurement is performed and the adjustment of the focus position of the measurement light LM can be performed as necessary.

The adjustment of the depth range is executed by the image processing unit 230 and the main control unit 211 as follows, for example.
-Analyzing sequentially acquired B-scan images and three-dimensional image data to draw a predetermined part of the eye E (for example, a part that is clearly expressed in an OCT image such as IS / OS, RPE, or ILM) The depth position (z coordinate value) in the frame being obtained is obtained.
The displacement between the obtained depth position and a predetermined target depth position is obtained.
-The optical path length difference between the measurement light LM and the reference light LR is adjusted by controlling the optical path length changing unit 41 so that the obtained displacement is canceled.
Note that this adjustment process can also be performed manually by displaying a B-scan image or the like as a moving image.

The adjustment of the focus position of the measurement light LM is executed as follows by the image processing unit 230 and the main control unit 211, for example.
Analyzing B-scan images, three-dimensional image data, and front cross-sectional images acquired sequentially to obtain an evaluation value indicating the image quality of the site of interest (IS / OS, RPE, ILM, etc.). In this process, an evaluation value indicating the image quality of a part other than the target part (for example, a part near the target part) may be obtained.
It is determined whether the image quality evaluation value obtained for the target region is equal to or greater than a predetermined threshold. In addition, when the evaluation value of image quality is obtained for a part other than the target part, it may be determined whether the evaluation value for the target part is better than the evaluation value for the part other than the target part.
The position of the focusing lens 43 is adjusted by controlling the OCT focusing drive unit 43A so that the evaluation value for the target region is equal to or greater than the threshold value. In addition, when the evaluation value is obtained for a part other than the target part, the OCT focusing drive unit 43A is controlled so that the evaluation value for the target part is better than the evaluation value for the part other than the target part. Thus, the position of the focusing lens 43 may be adjusted.

(S6: Freeze live front cross-sectional image)
The user performs a predetermined operation for freezing the front cross-sectional image displayed as a moving image via the operation unit 242. The main control unit 211 receives a signal corresponding to this operation from the operation unit 242, and switches the display mode of the front sectional image from the moving image display to the still image display. This still image is, for example, a frame displayed at the timing of the above operation.

(S7: The user specifies the cross-sectional position)
The user designates a cross-sectional position via the operation unit 242 for the front cross-sectional image displayed as a still image in step S6. This operation is performed, for example, by designating a region in the front sectional image using a pointing device such as a mouse. The display control unit 2111 can also be configured to display a mark indicating the cross-sectional shape on the front cross-sectional image and to specify the cross-sectional position by arbitrarily changing the position and orientation of the mark by the user. is there.

  The measurement control unit 2112 causes the storage unit 212 to store information indicating the designated cross-sectional position (cross-sectional position information). The cross-sectional position information is expressed using, for example, coordinates in the xyz coordinate system shown in FIG. 1, coordinates in a B scan image, or coordinates in three-dimensional coordinate data.

  FIG. 5A shows an aspect of the cross-sectional position designated for the front cross-sectional image. Assume that the front cross-sectional image H0 at the depth position z = z0 is displayed as a still image in step S6. Further, it is assumed that a lesion A0 is depicted in the front sectional image H0. The lesion A0 is, for example, a site where IS / OS or RPE is missing, or a site where the retina surface (ILM) is peeled off. A symbol B0 indicates a cross-sectional position set so as to pass through the lesion A0. This cross-sectional position B0 is set as a line segment. A symbol B in FIG. 5B indicates a two-dimensional section in the three-dimensional image data V corresponding to the designated section position B0. In the following processing, OCT measurement for imaging the two-dimensional section B is executed.

  The measurement control unit 2112 acquires information (cross-section position information) indicating the designated cross-section position. The acquired cross-sectional position information is stored in the storage unit 212, for example. The cross-sectional position information includes, for example, (1) coordinates in the xyz coordinate system shown in FIG. 1, (2) coordinates in the front cross-sectional image or three-dimensional image data, and (3) irradiation position of the measurement light LM in the live OCT measurement in step S4. May be included among the information which shows. The information shown in (1) to (3) is a parameter that can be converted to each other, and is substantially equivalent information.

(S8: Perform OCT measurement for diagnosis)
The measurement control unit 2112 controls the OCT unit 100 and the galvano scanner 42 based on the cross-sectional position information acquired in step S7, thereby executing OCT measurement for the cross-section specified by the user.

  A mode of this OCT measurement is shown in FIG. 5C. Reference numeral H denotes a surface area of the fundus oculi Ef corresponding to the front cross-sectional image H0 shown in FIG. 5A, that is, the surface area of the fundus oculi Ef when the three-dimensional image data V shown in FIG. Region when viewing the three-dimensional image data V). Symbol A represents a region obtained by projecting the lesion A0 at the depth position z = z0 onto the surface of the fundus oculi Ef along the z direction. A symbol L represents a region obtained by projecting the cross-sectional position B0 illustrated in FIG. 5A onto the surface of the fundus oculi Ef along the z direction, that is, a common region between the two-dimensional cross section B illustrated in FIG. 5B and the surface of the fundus oculi Ef.

  The OCT image acquired by the OCT measurement in this step is displayed on the display unit 241 by the display control unit 2111 and stored in the storage unit 212 by the main control unit 211, for example.

  In the OCT measurement of this step, a higher-definition image may be acquired by setting the scan interval (interval of the irradiation position of the measurement light LM) more densely than the live OCT measurement of step S4.

  Further, since the projection position of the fixation target has not been changed from step S1, if the galvano scanner 42 is controlled according to the cross-section position information acquired in step S7, the cross-section position designated by the user is substantially reproduced. be able to. In addition, when changing a fixation position between step S7 and step S8, it can comprise so that the galvano scanner 42 may be controlled after changing cross-sectional position information in consideration of the displacement corresponding to it.

  An aspect of OCT measurement in this step is shown in FIG. 5C. Reference numeral H denotes a surface area of the fundus oculi Ef corresponding to the front cross-sectional image H0 shown in FIG. 5A, that is, the surface area of the fundus oculi Ef when the three-dimensional image data V shown in FIG. Region when viewing the three-dimensional image data V). Symbol A represents a region obtained by projecting the lesion A0 at the depth position z = z0 onto the surface of the fundus oculi Ef along the z direction. A symbol L represents a region obtained by projecting the cross-sectional position B0 illustrated in FIG. 5A onto the surface of the fundus oculi Ef along the z direction, that is, a common region between the two-dimensional cross section B illustrated in FIG. 5B and the surface of the fundus oculi Ef. Therefore, according to this OCT measurement, it is possible to substantially reproduce the cross-sectional position designated by the user in step S7 (as long as the fixation is properly performed).

[Modification]
In the above operation example, the designation of the cross-sectional position is performed manually, but this process can be automated. When this automatic processing is applied, the image processing unit 230 has a cross-sectional position designation unit (not shown). The cross-section position specifying unit identifies the feature region in this frame by analyzing the frame of the live front cross-sectional image whose display is started in step S5. As this characteristic region, there are a predetermined part (optic nerve head, macular, blood vessel, etc.) of the eye E, a lesioned part, a treated part, and the like. This analysis process includes, for example, a process of analyzing a pixel value (luminance value) of a frame and a process of analyzing the shape of a tissue or the like drawn on the frame (pattern matching). The cross-sectional position specifying unit further specifies a feature point in the specified feature region. The feature points include, for example, the center position of the feature area, the center of gravity position, and the position on the edge. When the designated cross section has directionality (for example, when a two-dimensional cross section is set), the cross section position designating unit includes a process of setting the direction of the cross section. The specified direction may be a predetermined direction (for example, the x direction, the y direction, or the like), or may be a direction obtained by analysis of a frame or a feature region. In the former case, information indicating the default direction is stored in advance in the storage unit 212, for example. You may comprise so that a user can change this default direction arbitrarily. In the latter case, for example, the cross-section position designating unit obtains two or more feature points in the feature region, and can set the cross-section position so as to include these feature points (for example, pass through two feature points). It is. In addition, the cross-section position designation unit may be configured to obtain the contour of the feature region and designate the cross-section position based on the characteristics of the contour. As a specific example, the direction in which the diameter is maximum in the outline of the feature region can be set as the direction of the cross section. Further, since the front cross-sectional image is formed from three-dimensional image data, the cross-sectional position can be specified in consideration of image regions other than the front cross-sectional image in the three-dimensional image data.

  As described above, at least one of alignment, focusing, and tracking can be executed based on the OCT image. This OCT image may be, for example, a front sectional image (moving image or still image). Such a configuration will be described in the second and third embodiments.

  The live front cross-sectional image whose display is started in step S5 is not limited to one, and may be two or more. In this case, the cross-sectional image forming unit 232 includes n cross-sections (i-th cross-section: i = 1 to 2) having different depth positions (z coordinate values) from each three-dimensional image data formed by the three-dimensional image forming unit 231. n front sectional images corresponding to n) are formed. The display control unit 2111 causes the cross-sectional image forming unit 232 to display moving images of n front cross-sectional images corresponding to the first to n-th cross sections. The display mode of the n front cross-sectional images is not limited to a mode in which these are arranged and displayed, and a mode in which these are switched and displayed may be used. In this case, the display control unit 2111 causes the display unit 241 to display information indicating the first cross section to the n th cross section, for example. This information may be character string information indicating each cross section or image information indicating each cross section. As a display example of character string information, a tissue name corresponding to each cross section can be presented in a selectable manner. Further, as a display example of the image information, a stereoscopic image (for example, a rectangular parallelepiped schematic diagram, a rendering image based on the three-dimensional image data, etc.) indicating the shape of the three-dimensional image data is presented, and a cross-sectional position is displayed on the stereoscopic image. The image which shows can be shown. When displaying two or more front cross-sectional images, one of them may be a front cross-sectional image representing the fundus surface (ILM). This is effective when a function for taking a photograph of the fundus surface is not provided as in the fundus camera unit 2.

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

  The ophthalmologic observation apparatus according to this embodiment has an optical system for performing OCT measurement. This optical system includes at least a light source (light source unit 101), an optical element (fiber coupler 103) for splitting light output from the light source into measurement light and reference light, and scanning the eye to be examined with measurement light. Optical scanner (galvano scanner 42), optical element (fiber coupler 109) for causing the return light of the measurement light from the subject's eye to interfere with the reference light, and the interference light obtained by this optical element is detected And a photodetector (CCD image sensor 115).

  Furthermore, the ophthalmologic observation apparatus according to this embodiment includes a three-dimensional image acquisition unit (image forming unit 220 and three-dimensional image forming unit 231), a cross-sectional image forming unit (cross-sectional image forming unit 232), and a display control unit (display). A control unit 2111) and a measurement control unit (measurement control unit 2112). The optical system repeatedly performs OCT measurement on the three-dimensional region of the eye to be examined. The three-dimensional image acquisition unit sequentially acquires a three-dimensional image of the eye to be examined based on data sequentially acquired by the optical system in this repetitive OCT measurement. The cross-sectional image forming unit sequentially forms front cross-sectional images based on the three-dimensional images sequentially acquired by the three-dimensional image acquisition unit. The display control unit causes the display unit to display a moving image of the front cross-sectional image sequentially formed by the cross-sectional image forming unit. The measurement control unit causes the optical system to perform OCT measurement for the cross-sectional position designated via the operation unit with respect to the front cross-sectional image displayed on the display unit.

  The display means may be a part of the ophthalmic observation apparatus (display unit 241) or may be provided outside the display unit. Similarly, the operation means may be a part of the ophthalmologic observation apparatus (operation unit 242) or may be provided outside the operation means.

  According to such an ophthalmologic observation apparatus, it is possible to set the cross-sectional position using the front cross-sectional image of the eye to be examined acquired by (preliminary) OCT measurement, and to perform OCT measurement of the set cross-sectional position. It is possible to execute.

  The display control unit may be configured to switch the display mode of the front cross-sectional image from the moving image display to the still image display in response to a predetermined operation being performed via the operation unit. That is, the display control unit may be configured to perform a freeze display of a moving image. In this case, it is possible to specify the cross-sectional position for the front cross-sectional image displayed as a still image. According to this configuration, it is possible to facilitate the operation of specifying the cross-sectional position in the front cross-sectional image.

  The cross-sectional image forming unit may be configured to form an image having a cross-section at a preset depth position of the eye as a front cross-sectional image. In this case, the preset depth position of the eye to be examined is the depth position corresponding to the photoreceptor inner / outer segment junction (IS / OS) and the depth position corresponding to the retinal pigment epithelium (RPE). Of these, at least one of them may be included. Alternatively, the preset depth position of the eye to be examined may include a depth position closer to the cornea than the fundus surface. In this case, the depth position on the cornea side of the fundus surface is a predetermined depth position in the vitreous body (for example, a position on the cornea side by a predetermined distance from the fundus surface) and a predetermined depth position in the exfoliated tissue from the retina. For example, in the peeled ILM, at least one of the corneal side positions from the fundus surface may be included. By providing the cross-sectional image forming section having such a configuration, a front cross-sectional image corresponding to a desired depth position of the eye to be examined (for example, a depth position that is particularly noted under a certain condition (such as a disease name)) can be easily obtained. Can be observed. Moreover, it is possible to suitably specify the cross-sectional position.

<Second Embodiment>
In this embodiment, an ophthalmic observation apparatus that can execute at least one of alignment, focusing, and tracking based on an OCT image will be described.

[Constitution]
The ophthalmic observation apparatus according to this embodiment has, for example, the same overall configuration and optical system as those of the first embodiment (see FIGS. 1 and 2). A configuration example of the control system of the ophthalmologic observation apparatus according to this embodiment is shown in FIG. In FIG. 6, some components are omitted (see FIG. 3). Hereinafter, a part different from the first embodiment will be particularly described. Moreover, in the following description, the code | symbol used in 1st Embodiment is applied mutatis mutandis.

  The main control unit 211 includes an alignment control unit 2113, a focus control unit 2114, and a tracking control unit 2115 in addition to the display control unit 2111 and the measurement control unit 2112 that are the same as those in the first embodiment. The alignment control unit 2113 performs control related to the alignment using the OCT image (front sectional image). The focus control unit 2114 performs control related to focusing of the measurement light using the front cross-sectional image. The tracking control unit 2115 performs control related to tracking of the apparatus optical system using the front cross-sectional image. Processing executed by these control units 2113 to 2115 will be described later. Moreover, the ophthalmologic observation apparatus according to this embodiment may have at least one of these control units 2113 to 2115.

  The image processing unit 230 includes an image displacement calculation unit 233, a depth position calculation unit 234, and an eye displacement acquisition unit 235 in addition to the three-dimensional image formation unit 231 and the cross-sectional image formation unit 232 that are the same as those in the first embodiment. And have. The image displacement calculation unit 233 generates information used in alignment. The depth position calculation unit 234 generates information used in focusing. The subject eye displacement acquisition unit 235 generates information used in tracking. Note that the information used in alignment and the information used in tracking may be the same type of information. In this case, the image displacement calculation unit 233 and the eye displacement acquisition unit 235 can be configured integrally.

(Image displacement calculator)
The image displacement calculation unit 233 analyzes the front cross-sectional image formed by the cross-sectional image forming unit 232 to calculate the displacement of the image of the predetermined part of the eye E with respect to the predetermined position in the front cross-sectional image. This process includes, for example, the following processes: a process of analyzing a front cross-sectional image to specify an image (region) of a predetermined part of the eye E to be examined; a specified image (or a feature point in the image) and a front cross-section A process for obtaining a displacement between a predetermined position of an image. The image displacement calculation unit 233 may be configured to sequentially perform the above processing on the front cross-sectional images sequentially formed by the cross-sectional image forming unit 232.

  The predetermined part of the eye E is a predetermined part, for example, a characteristic part of the eye E (optic nerve head, macula, blood vessel, etc.), a lesioned part, or a treated part. The predetermined position in the front sectional image may be a preset position or a position set in the analysis process. As an example of the former case, there is a predetermined position (for example, a center position) in the frame. As an example of the latter case, there is a drawing position of an image of a characteristic part of the eye E in any one of a plurality of front cross-sectional images acquired sequentially.

(Depth position calculator)
The depth position calculation unit 234 calculates the depth position of the eye E corresponding to the front cross-sectional image formed by the cross-sectional image forming unit 232. This processing includes, for example, the following processing: (1) Processing for obtaining the z-coordinate value of the front sectional image in the three-dimensional image data; (2) Depth position of the eye E corresponding to the obtained z-coordinate value. The requested process. The depth position calculation unit 234 may be configured to sequentially perform the above processing on the front cross-sectional images sequentially formed by the cross-sectional image forming unit 232.

  Note that since the distance (working distance) between the eye E and the apparatus optical system when OCT measurement is performed is predetermined, the depth position of the eye E and the position of the focusing lens 43 are associated in advance. be able to. When this association is made, the depth position of the eye E and the position of the focusing lens 43 are identified with each other. That is, the process (2) is equivalent to the process for obtaining the position of the focusing lens 43 corresponding to the z coordinate value acquired in (1).

  In the process (1), for example, the z coordinate value (the coordinate information of the cross section represented by the front cross-sectional image) applied in the process of forming the front cross-sectional image from the three-dimensional image data is acquired from the cross-sectional image forming unit 232. Done.

  In the process (2), for example, the z coordinate value (z coordinate value in the definition coordinate system of the image data) acquired in the process (1) is used as the depth position of the eye E (z coordinate value in real space). Alternatively, it is performed by converting into the position of the focusing lens 43.

(Eye displacement acquisition unit)
The subject eye displacement acquisition unit 235 sequentially acquires the displacement (motion state) of the eye E by analyzing the front sectional images sequentially formed by the sectional image forming unit 232. That is, the eye displacement acquisition unit 235 has a function of monitoring the movement of the eye E based on the front cross-sectional images acquired sequentially. The process performed on each front cross-sectional image may be the same as the process executed by the image displacement calculation unit 233. In other words, the eye displacement acquisition unit 235 repeatedly executes the following process, for example.
-Analyzing the front cross-sectional image to determine the position of the characteristic region corresponding to the characteristic part of the eye E (for example, the center of the pupil in the anterior segment image and the center of the macula, nipple or lesion in the fundus image) .
The displacement between the position of the feature area obtained this time and the position of the feature area obtained in the previous process is obtained.
In addition, it can be said that these processes replaced the near-infrared observation image referred by the tracking of 1st Embodiment with the front cross-sectional image.

[Operation]
The operation of the ophthalmologic observation apparatus according to this embodiment will be described. FIG. 7 shows an example of the operation of the ophthalmologic observation apparatus. In this operation example, a case where alignment, focusing, and tracking are executed based on a front cross-sectional image of the eye E will be described.

(S11: Rough alignment and rough focusing are performed)
First, rough alignment is performed. Rough alignment represents rough alignment of the apparatus optical system with respect to the eye E (fundus Ef). Rough focusing represents rough focusing of the apparatus optical system with respect to the eye E (fundus Ef). These processes are executed manually or automatically using a near-infrared observation image as in the first embodiment, for example. Note that tracking based on a near-infrared observation image may be started after completion of rough alignment and rough focusing.

(S12: Start live OCT measurement)
Upon completion of rough alignment and rough focusing, the main control unit 211 starts live OCT measurement by controlling the OCT unit 100 and the galvano scanner 42. Live OCT measurement is executed, for example, in the same manner as in the first embodiment. A three-dimensional scan is applied as the scan pattern.

(S13: Start displaying the live front sectional image)
The image forming unit 220 sequentially forms B scan images based on detection signals input at a predetermined rate from the CCD image sensor 115 in the live OCT measurement in step S12. For example, the main control unit 211 sequentially sends a plurality of B scan images corresponding to one 3D scan to the 3D image forming unit 231. The three-dimensional image forming unit 231 forms three-dimensional image data corresponding to the three-dimensional scan based on a plurality of B scan images corresponding to one three-dimensional scan. The cross-sectional image forming unit 232 forms a front cross-sectional image in a preset cross section based on each three-dimensional image data formed by the three-dimensional image forming unit 231. This cross section may be set for a tissue that a user particularly pays attention to, such as IS / OS, RPE, or ILM. The display control unit 2111 causes the display unit 241 to display the front cross-sectional images sequentially formed by the cross-sectional image forming unit 232 at a predetermined rate. Thereby, a live moving image representing the cross section is displayed.

  In this step, for example, as in the first embodiment, the adjustment of the depth range in which the OCT measurement is performed and the adjustment of the focal position of the measurement light LM can be performed as necessary.

(S14: Perform alignment based on the front cross-sectional image)
Next, alignment based on the front cross-sectional image is performed. This process is executed as follows, for example. First, the image displacement calculating unit 233 analyzes the front cross-sectional image formed by the cross-sectional image forming unit 232, for example, in the manner described above, and thereby an image of a predetermined part of the eye E with respect to a predetermined position in the front cross-sectional image. The displacement of is calculated. Information indicating the calculated displacement of the image is sent to the alignment control unit 2113. The alignment control unit 2113 moves the apparatus optical system by controlling the optical system drive unit 2A so as to cancel the displacement of the image calculated by the image displacement calculation unit 233.

(S15: Focusing based on the front cross-sectional image is performed)
Subsequently, focusing based on the front cross-sectional image is performed. This process is executed as follows, for example. First, the depth position calculation unit 234 calculates the depth position of the eye E corresponding to the front cross-sectional image formed by the cross-sectional image forming unit 232, for example, in the manner described above. Information indicating the calculated depth position is sent to the focus control unit 2114. The focus control unit 2114 controls the OCT focusing drive unit 43A based on this information to move the focusing lens 43, thereby focusing the measurement light LM on the depth position calculated by the depth position calculation unit 234. Match.

(S16: Start tracking based on front cross-sectional image)
When the alignment and focusing are completed, the main control unit 211 starts tracking based on the front cross-sectional image. In tracking, for example, the following processing is repeatedly executed.
The eye displacement acquisition unit 235 acquires the displacement of the eye E by analyzing the front cross-sectional image formed by the cross-sectional image forming unit 232.
The eye displacement acquisition unit 235 obtains a displacement between the position of the feature area obtained this time and the position of the feature area obtained in the previous process.
The tracking control unit 2115 moves the apparatus optical system by controlling the optical system driving unit 2A so that the obtained displacement is canceled.

(S17: Freeze live front cross-sectional image)
When the user performs a freeze operation at an arbitrary timing, the main control unit 211 switches the display mode of the front sectional image from the moving image display to the still image display.

(S18: The user specifies the cross-sectional position)
The user designates a cross-sectional position for the front cross-sectional image displayed as a still image in step S17, for example, as in the first embodiment. The measurement control unit 2112 causes the storage unit 212 to store information indicating the designated cross-sectional position (cross-sectional position information).

(S19: Perform OCT measurement for diagnosis)
As in the first embodiment, the measurement control unit 2112 controls the OCT unit 100 and the galvano scanner 42 based on the cross-sectional position information acquired in step S18, thereby performing OCT measurement on the cross-section specified by the user. Let it run. The OCT image acquired by the OCT measurement is displayed on the display unit 241 by the display control unit 2111 and stored in the storage unit 212 by the main control unit 211, for example.

  Any operation (operation example, modification example) described in the first embodiment can be applied to this operation example.

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

  Similar to the first embodiment, the ophthalmic observation apparatus according to this embodiment includes an optical system for performing OCT measurement, a three-dimensional image acquisition unit, a cross-sectional image forming unit, and a measurement control unit. Further, the ophthalmic observation apparatus includes a moving mechanism (optical system driving unit 2A), an image displacement calculating unit (image displacement calculating unit 233), an alignment control unit (alignment control unit 2113), and a depth position calculating unit (depth). A position calculation unit 234), a focus control unit (focus control unit 2114), a displacement acquisition unit (examined eye displacement acquisition unit 235), and a tracking control unit (tracking control unit 2115).

  As described above, in this embodiment, it is sufficient that at least one of alignment, focusing, and tracking is applied. When the alignment is not applied, the ophthalmologic observation apparatus does not have an image displacement calculation unit and an alignment control unit. In this case, for example, alternative alignment can be executed by using a near-infrared observation image. When focusing is not applied, the ophthalmic observation apparatus does not have a depth position calculation unit and a focus control unit. In this case, for example, alternative focusing can be performed by using a near-infrared observation image. When tracking is not applied, the ophthalmic observation apparatus does not include a displacement acquisition unit and a tracking control unit. In this case, for example, alternative tracking can be executed by using a near-infrared observation image.

  In the ophthalmologic observation apparatus according to this embodiment, the display control unit described in the first embodiment may be additionally provided. Further, display means and / or operation means may be additionally provided. When these are provided, similarly to the first embodiment, designation of a cross-sectional position with respect to the front cross-sectional image and OCT measurement with respect to the designated cross-sectional position can be performed.

  The moving mechanism moves the optical system for OCT measurement.

  The image displacement calculation unit calculates a displacement of an image of a predetermined portion of the eye to be examined with respect to a predetermined position in the front cross-sectional image by analyzing the front cross-sectional image formed by the cross-sectional image forming unit. The alignment control unit executes the alignment by controlling the moving mechanism based on the displacement calculated by the image displacement calculating unit.

  The depth position calculation unit calculates the depth position of the eye to be examined corresponding to the front cross-sectional image formed by the cross-sectional image forming unit. The focus control unit focuses the optical system on the depth position calculated by the depth position calculation unit after the control by the alignment control unit (that is, executes focusing). Note that the depth position calculation processing by the depth position calculation unit may be performed before the alignment control, may be performed after the alignment control, or may be performed in parallel with this.

  The displacement acquisition unit sequentially acquires the displacement of the eye to be examined by analyzing the front cross-sectional images sequentially formed by the cross-sectional image forming unit after the control by the alignment control unit and the control by the focus control unit. . The tracking control unit performs tracking by sequentially controlling the movement mechanism based on the displacement of the eye to be examined sequentially acquired by the displacement acquisition unit.

  The measurement control unit causes the optical system to perform OCT measurement in response to the input of a predetermined trigger when control (tracking) is performed by the tracking control unit. The trigger is input manually or automatically, for example. The manual trigger input is, for example, a predetermined operation by the user. As an example of automatic trigger input, a determination result that the tracking state is stable may be obtained. This determination process is performed as follows, for example. The measurement control unit (or the displacement acquisition unit) determines whether the displacement of the eye to be examined sequentially acquired by the displacement acquisition unit is equal to or less than a predetermined threshold, and the determination result “YES (displacement ≦ threshold)” is a predetermined number of times (or The trigger is generated when it is obtained continuously for a predetermined time.

  The effect when alignment is applied will be described. Since the front cross-sectional image is a front image of the eye to be examined like the near-infrared observation image, the alignment based on the front cross-sectional image is executed in a manner similar to the alignment based on the near-infrared observation image of the first embodiment. be able to. However, there is a case where the site of interest exists in a deep region of the fundus (a region that cannot be imaged by the near-infrared observation image). In this case, the alignment based on the near-infrared observation image accurately positions the site of interest. Cannot be matched. On the other hand, according to this embodiment, since alignment can be performed based on a front cross-sectional image having a cross section at an arbitrary depth position, it is possible to image a site of interest existing in a deep region. .

  The effect when focusing is applied will be described. This embodiment is configured to calculate the depth position of the eye to be examined corresponding to the frontal cross-sectional image formed by the cross-sectional image forming unit, and to focus the optical system on the calculated depth position. . This front cross-sectional image is an image formed based on live OCT measurement, and in particular, is an image representing a part that the user is paying attention to. Therefore, according to this embodiment, it is possible to automatically focus on the target region of the eye to be examined. Therefore, it is possible to easily acquire an OCT image in which a site of interest is drawn with high definition.

  The effect when tracking is applied will be described. Tracking is performed after alignment and focusing are performed, and acts to maintain the adjusted alignment state and focus state, respectively. Therefore, according to this embodiment, it is possible to perform tracking so as to maintain the alignment state and the focus state that are matched to the target region existing in the deep region. Therefore, the region of interest existing in the deep region can be reliably imaged.

  The cross-sectional image forming unit may be configured to form an image having a cross-section at a preset depth position of the eye as a front cross-sectional image. In this case, the depth position of the eye to be set in advance may include at least one of a depth position corresponding to IS / OS and a depth position corresponding to RPE. Alternatively, the preset depth position of the eye to be examined may include a depth position closer to the cornea than the fundus surface. In this case, the depth position closer to the cornea than the fundus surface may include at least one of a predetermined depth position in the vitreous body and a predetermined depth position in the exfoliated tissue from the retina. By providing the cross-sectional image forming section having such a configuration, it is possible to easily observe a front cross-sectional image corresponding to a particularly focused depth position at a desired depth position of the eye to be examined. Moreover, it is possible to suitably specify the cross-sectional position.

<Third Embodiment>
In this embodiment, an ophthalmologic observation apparatus capable of executing registration of front sectional images will be described. Registration refers to a process of aligning images.

[Constitution]
The ophthalmic observation apparatus according to this embodiment has, for example, the same overall configuration and optical system as those of the first embodiment (see FIGS. 1 and 2). A configuration example of a control system of the ophthalmologic observation apparatus according to this embodiment is shown in FIG. Hereinafter, a part different from the first embodiment will be particularly described. Moreover, in the following description, the code | symbol used in 1st Embodiment is applied mutatis mutandis.

  The storage unit 212 stores in advance a front cross-sectional image (referred to as a past front cross-sectional image) acquired in the past for the eye E. The image processing unit 230 includes an image alignment unit 236 in addition to the same three-dimensional image forming unit 231 and cross-sectional image forming unit 232 as those in the first embodiment.

(Previous front cross-sectional image)
The past front cross-sectional image stored in the storage unit 212 is a front cross-sectional image formed based on OCT measurement performed on the eye E in the past. This past OCT measurement is performed using this ophthalmic observation apparatus or another OCT apparatus. When past OCT measurement is performed by another OCT apparatus, data acquired in the past is input to the ophthalmologic observation apparatus via a communication line or a storage medium. Data input via the communication line is performed using a communication interface included in the control unit 210. Data input via the storage medium is performed using an interface (not shown) (drive device, data reader, connector, etc.).

  The past front cross-sectional image may be an image based on OCT measurement performed in the past. Therefore, the past front cross-sectional image is not limited to the front cross-sectional image formed in the past, but data obtained by past OCT measurement (for example, a plurality of A-scan images, a plurality of B-scan images, and three-dimensional image data). ) May be a front cross-sectional image formed in the current inspection. In that case, the process of forming the front cross-sectional image is performed by the image processing unit 230 (the three-dimensional image forming unit 231 and the cross-sectional image forming unit 232).

(Image alignment part)
The image alignment unit 236 analyzes the front cross-sectional image formed by the cross-sectional image forming unit 232 (referred to as a new front cross-sectional image) and the past front cross-sectional image stored in the storage unit 212 to obtain a new cross-sectional image. The front sectional image and the past front sectional image are aligned. This alignment process includes the following first to fourth steps, for example.

  As a first step, the image alignment unit 236 identifies a feature region in the new front cross-sectional image by analyzing the new front cross-sectional image. The feature region is, for example, a region corresponding to a feature portion of the eye E (optic nerve head, macular, blood vessel, lesion, treated portion, etc.). The characteristic part may be set in advance or may be set in this process.

  As a second step, the image alignment unit 236 identifies a feature region in the past front sectional image by analyzing the past front sectional image. This feature region is the same type as the feature region in the first step.

  The order in which the first step and the second step are performed is arbitrary. That is, either the first step or the second step may be performed first, or these steps may be performed in parallel. Further, as described above, the feature regions applied in these steps need to be the same type, but a certain type of feature region applied may not be specified in one or both steps. In order to deal with such a case, the image registration unit 236 can be configured so that a plurality of types of feature regions can be specified. In this case, the image registration unit 236 can be configured to collectively specify a plurality of types of feature regions. Alternatively, the image registration unit 236 may be configured such that priorities are set in advance for a plurality of types, and the plurality of types are sequentially applied until a feature region is specified in both steps. Good.

  As a third step, the image alignment unit 236 displaces the feature region (new feature region) specified in the first step and the feature region (past feature region) specified in the second step. Is calculated. In this process, for example, the position (coordinates) of a new feature region in the frame of the new front cross-sectional image and the position (coordinates) of the past feature region in the frame of the previous front cross-sectional image are obtained, and the displacement of these positions is obtained. Is done by asking.

  The displacement obtained in the third step may include a displacement corresponding to a parallel movement and a displacement corresponding to a rotational movement. In this case, for example, the image alignment unit 236 may include, for example, a feature region in the new front cross-sectional image (its contour or a plurality of feature points) and a feature region in the past front cross-sectional image (its contour or a plurality of features). It is configured to obtain an affine transformation (affine matrix) that matches a feature point.

  As a fourth step, the image alignment unit 236 relatively moves (translates and rotates) the new front cross-sectional image and the past front cross-sectional image so as to cancel the displacement obtained in the third step. ) This relative movement may be any of a case where only a new front cross-sectional image is moved, a case where only a past front cross-sectional image is moved, and a case where both are moved.

[Operation]
The operation of the ophthalmologic observation apparatus according to this embodiment will be described. FIG. 9 shows an example of the operation of the ophthalmologic observation apparatus. It is assumed that the storage unit 212 stores (one or more) past front cross-sectional images. Information (past cross-sectional position information) indicating the cross-sectional position may be attached to the past front cross-sectional image. For example, the past cross-sectional position information can be determined based on the coordinates in the xyz coordinate system shown in FIG. 1, the coordinates in the B-scan image, or the coordinates in the three-dimensional coordinate data, as in the cross-sectional position information described in the first embodiment. This is information representing the cross-sectional position of the front cross-sectional image. The past front cross-sectional image may be associated with the patient ID.

(S21: Read out the past front sectional image)
First, the main control unit 211 reads a past front cross-sectional image stored in the storage unit 212 and sends it to the image alignment unit 236. This reading process is read with reference to the patient ID of the subject, for example. Further, when past cross-section position information is attached, the past cross-section position information is also read and sent to the image processing unit 230 (for example, the cross-sectional image forming unit 232).

  When a plurality of past front cross-sectional images related to the subject are stored, the main control unit 211 can display the list (character string information indicating cross-sectional positions, thumbnail images, etc.) on the display unit 241. Then, in response to the user selecting the past front cross-sectional image using the operation unit 242, the main control unit 211 sends the selected past front cross-sectional image to the image alignment unit 236. In addition, when two or more past front cross-sectional images are selected, the process described later is executed for each of these past front cross-sectional images.

(S22: Start this examination)
For example, the current examination is started in response to the user performing a predetermined operation.

(S23: Perform alignment and focusing)
In this inspection, alignment and focusing are performed first. The mode of alignment and focusing in this step is arbitrary. For example, as in the first embodiment, alignment and focusing may be performed using a near-infrared observation image. Or after performing rough alignment and rough focusing like 2nd Embodiment, you may perform alignment and focusing by an OCT image. The alignment and focusing may be manual or automatic.

(S24: Start tracking)
After completing alignment and focusing, tracking is started. The mode of tracking in this step is arbitrary. For example, tracking may be performed using a near-infrared observation image as in the first embodiment, or tracking may be performed using an OCT image as in the second embodiment. It is also possible to configure so that tracking is not executed.

(S25: Start live OCT measurement)
At an arbitrary timing after the start of tracking, the main controller 211 controls the OCT unit 100 and the galvano scanner 42 to start live OCT measurement. Live OCT measurement is executed, for example, in the same manner as in the first embodiment. A three-dimensional scan is applied as the scan pattern.

(S26: A new front cross-sectional image in the same cross section as the past front cross-sectional image is sequentially formed)
The image forming unit 220 sequentially forms B scan images based on detection signals input at a predetermined rate from the CCD image sensor 115 in the live OCT measurement in step S25. For example, the main control unit 211 sequentially sends a plurality of B scan images corresponding to one 3D scan to the 3D image forming unit 231. The three-dimensional image forming unit 231 forms three-dimensional image data corresponding to the three-dimensional scan based on a plurality of B scan images corresponding to one three-dimensional scan. The formed three-dimensional image data is sent to the cross-sectional image forming unit 232.

  As described in step 21, past sectional position information indicating the sectional position of the past front sectional image is input to the sectional image forming unit 232. The cross-sectional image forming unit 232, based on each three-dimensional image data formed by the three-dimensional image forming unit 231 and past cross-section position information, a front cross-sectional image (new front cross-section) in the cross-section indicated by the past cross-section position information. Image). The formed new front sectional image is sequentially sent to the image alignment unit 236.

(S27: The alignment of the past front sectional image and the new front sectional image is sequentially performed)
The image alignment unit 236 performs alignment between the new front cross-sectional image and the past front cross-sectional image for new front cross-sectional images sequentially input from the cross-sectional image forming unit 232. This image alignment process is executed, for example, as described above. The image alignment unit 236 sequentially sends new front cross-sectional images that have undergone image alignment processing to the display control unit 2111.

(S28: A new front sectional image (and past front sectional image) that has been aligned is displayed)
The display control unit 2111 causes the display unit 241 to display new front sectional images sequentially input from the image alignment unit 236 at a predetermined rate. Thereby, a live moving image representing the same cross section as the past front cross-sectional image is displayed. The display control unit 241 can display the past front cross-sectional image together with the live moving image. These two types of images are presented side by side on a display screen, for example. As is apparent from step S27, these two types of images are aligned with each other.

  In this step, for example, in the manner described in the first embodiment or the second embodiment, the depth range in which the OCT measurement is performed and the focus position of the measurement light LM are adjusted as necessary. Can do.

(S29: Perform OCT measurement for diagnosis)
The user can specify the cross-sectional position in the same manner as in the first embodiment, for example. The measurement control unit 2112 controls the OCT unit 100 and the galvano scanner 42 based on the designated cross-sectional position to execute OCT measurement. The OCT image acquired by the OCT measurement is displayed on the display unit 241 by the display control unit 2111 and stored in the storage unit 212 by the main control unit 211, for example.

  Arbitrary operations (operation examples and modifications) described in the first embodiment and the second embodiment can be applied to this operation example.

  When the OCT measurement scan pattern in this step is a three-dimensional scan (particularly when a further front cross-sectional image is formed), the process may proceed to the next step S30. In other cases, the description of this operation example ends here.

(S30: A new front sectional image and a past front sectional image are aligned)
When the 3D scan is applied in step S29, the image forming unit 220 and the 3D image forming unit 231 form 3D image data based on the data acquired by the 3D scan. The cross-sectional image forming unit 232 forms a cross-sectional image in an arbitrary cross section based on the three-dimensional image data. In this process, a front cross-sectional image (new front cross-sectional image) in the same cross section as the past front cross-sectional image may be formed.

  When a new front cross-sectional image is formed in this step, the image alignment unit 236 can perform alignment between the new front cross-sectional image and the past front cross-sectional image. Further, the image alignment unit 236 can extend the alignment result to 3D image data. That is, the image alignment unit 236 can relatively move the three-dimensional image data and the past front sectional image so that the displacement between the new front sectional image and the past front sectional image is canceled. . As a result, the three-dimensional image data and the past front cross-sectional image are aligned in the xy direction. That is, an arbitrary image formed based on the three-dimensional image data is aligned with the past frontal cross-sectional image.

(S31: A new front sectional image (and a past front sectional image) aligned is displayed)
The display control unit 2111 can cause the display unit 241 to display a new front cross-sectional image that has been aligned with the past front cross-sectional image in step S30. At this time, it is also possible to display a past front cross-sectional image.

  When the alignment between the three-dimensional image data and the past front cross-sectional image is performed in step S30, the cross-sectional image forming unit 232 can form a cross-sectional image in an arbitrary cross section based on the three-dimensional image data. it can. Further, the display control unit 2111 can cause the display unit 241 to display the cross-sectional image formed by the cross-sectional image forming unit 232. This cross-sectional image is aligned with the past front cross-sectional image.

  As another example, the image processing unit 230 can form a pseudo three-dimensional image by rendering the three-dimensional image data aligned with the past frontal cross-sectional image. The pseudo three-dimensional image is displayed on the display unit 241 by the display control unit 2111. This pseudo three-dimensional image is aligned with the past front cross-sectional image. This is the end of the description of this operation example.

[Modification]
In the above operation example, the same cross section as the previous front cross-sectional image read out earlier is imaged, but the present invention is not limited to this. For example, the front cross-sectional image obtained by the current OCT measurement represents a predetermined cross-section, and the past front cross-sectional image corresponding to this cross-section is selectively read out from the storage unit 212 and the alignment process is performed. Is possible. Alternatively, the front cross-sectional image corresponding to the cross-section of the front cross-sectional image obtained by the current OCT measurement may be formed from the three-dimensional image data stored in the storage unit 212, and the alignment process may be performed. Is possible.

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

  Similar to the first embodiment, the ophthalmic observation apparatus according to this embodiment includes an optical system for performing OCT measurement, a three-dimensional image acquisition unit, and a cross-sectional image formation unit. Furthermore, the ophthalmologic observation apparatus includes a storage unit (storage unit 212) and an image registration unit (image registration unit 236).

  In the storage unit, past front cross-sectional images acquired in the past for the eye to be examined are stored in advance. The image alignment unit analyzes the front sectional image formed by the sectional image forming unit and the past front sectional image stored in the storage unit, thereby aligning the front sectional image and the past front sectional image. I do.

  According to such an ophthalmologic observation apparatus, registration between a front cross-sectional image acquired in the past and a newly acquired front cross-sectional image can be performed. In the conventional registration, images on the fundus surface are aligned with each other. However, there is a case where a site of interest exists in the deep region of the fundus, and in that case, registration in consideration of the site of interest cannot be performed. On the other hand, according to this embodiment, since registration can be performed based on a front cross-sectional image having a cross section at an arbitrary depth position, it is possible to perform registration in consideration of a site of interest existing in a deep region. Become.

  The cross-sectional image forming unit may be configured to form an image having a cross-section at a preset depth position of the eye as a front cross-sectional image. In this case, the depth position of the eye to be set in advance may include at least one of a depth position corresponding to IS / OS and a depth position corresponding to RPE. Alternatively, the preset depth position of the eye to be examined may include a depth position closer to the cornea than the fundus surface. In this case, the depth position closer to the cornea than the fundus surface may include at least one of a predetermined depth position in the vitreous body and a predetermined depth position in the exfoliated tissue from the retina. By providing the cross-sectional image forming section having such a configuration, it is possible to easily observe a front cross-sectional image corresponding to a particularly focused depth position at a desired depth position of the eye to be examined. Moreover, it is possible to suitably specify the cross-sectional position.

<Fourth Embodiment>
In this embodiment, an ophthalmic observation apparatus capable of displaying two or more front sectional images corresponding to two or more depth positions (cross-sectional positions) as live moving images will be described. Some examples of such processing are briefly described in the above embodiment.

  The ophthalmologic observation apparatus according to this embodiment has the same configuration as that of the first embodiment (see FIGS. 1 to 3), for example. However, the cross-sectional image forming unit 232 sequentially forms two or more front cross-sectional images corresponding to two or more cross-sections having different depth positions based on each of the three-dimensional image data sequentially formed by live OCT measurement. To do. Two or more cross sections are designated manually or automatically. The automatic designation of the cross section is performed by the image processing unit 230 (cross section position designating unit) as described in the first embodiment, for example. Hereinafter, some examples of two or more cross sections applied in this embodiment will be described.

  FIG. 10A shows an outline when two cross sections are set. FIG. 10A shows a first front cross-sectional image H1 at the first depth position z = z1 and a second front cross-sectional image H2 at the second depth position z = z2. A lesion A1 is drawn on the first front sectional image H1, and a lesion A2 is drawn on the second front sectional image H2. The first front cross-sectional image H1 and the second front cross-sectional image H2 are formed by the cross-sectional image forming unit 232 based on the three-dimensional image data V.

  FIG. 10B shows ILM (inner boundary membrane, fundus surface), IS / OS (inner joint segment of photoreceptor cells) and RPE (retinal pigment epithelium) as examples of the fundus (retinal) tissue. Has been. FIG. 10B shows the form of these tissues in a B-scan image. A combination of the first front cross-sectional image H1 and the second front cross-sectional image H2 corresponds to a combination of any two of ILM, IS / OS, and RPE. For example, when the first front cross-sectional image H1 is set to ILM and the second front cross-sectional image H2 is set to IS / OS, a first live moving image representing ILM (fundus surface), IS / A second live moving image representing the OS is displayed on the display unit 241. Note that the display control unit 2111 can display these live moving images side by side on the display screen, or can switch these live moving images (in response to a predetermined trigger) to display them. When three or more front sectional images having different depth positions are formed, three or more live moving images corresponding to three or more depth positions including ILM, IS / OS, and RPE are displayed. Is displayed.

  FIG. 10C shows a retinal detachment site D in addition to ILM, IS / OS, and RPE similar to FIG. 10B. Reference symbol G indicates a vitreous body. When observing the retinal detachment site D or the vitreous body, one or more of the two or more depth positions are set on the cornea side of the retina. That is, in the example shown in FIG. 10A, at least the first depth position z = z1 is set as such. Reference symbol F in FIG. 10C indicates a cross section corresponding to a depth position set on the cornea side of the retina.

  As in the first embodiment, the ophthalmic observation apparatus according to this embodiment includes an optical system for performing OCT measurement, a three-dimensional image acquisition unit, a cross-sectional image formation unit, and a display control unit. The cross-sectional image forming unit 2 corresponds to two or more cross-sections (z = z1, z2,...) Having different depth positions based on each of the three-dimensional images sequentially acquired by the three-dimensional image acquisition unit. The above front sectional images (H1, H2,...) Are sequentially formed. The display control unit displays two or more frontal cross-sectional images sequentially formed by the cross-sectional image forming unit on the display unit as moving images.

  According to the ophthalmologic observation apparatus according to this embodiment, it is possible to observe two or more cross sections having different depth positions as moving images.

  The cross-sectional image forming unit may be configured to form an image having a cross-section at a preset depth position of the eye as a front cross-sectional image. In this case, the depth position of the eye to be set in advance may include at least one of a depth position corresponding to IS / OS and a depth position corresponding to RPE. Alternatively, the preset depth position of the eye to be examined may include a depth position closer to the cornea than the fundus surface. In this case, the depth position closer to the cornea than the fundus surface may include at least one of a predetermined depth position in the vitreous body and a predetermined depth position in the exfoliated tissue from the retina. By providing the cross-sectional image forming section having such a configuration, it is possible to easily observe a front cross-sectional image corresponding to a particularly focused depth position at a desired depth position of the eye to be examined. Moreover, it is possible to suitably specify the cross-sectional position.

<Modification>
The configuration described above is merely an example for carrying out the present invention. Therefore, arbitrary modifications (omitted, replacement, addition, etc.) within the scope of the present invention can be made as appropriate.

  In the above embodiment, the optical path length difference between the optical path of the measurement light LM and the optical path of the reference light LR is changed by changing the position of the optical path length changing unit 41. However, this optical path length difference is changed. The method is not limited to this. For example, it is possible to change the optical path length difference by disposing a reflection mirror (reference mirror) in the optical path of the reference light and moving the reference mirror in the traveling direction of the reference light to change the optical path length of the reference light. Is possible. Further, the optical path length difference may be changed by moving the fundus camera unit 2 or the OCT unit 100 with respect to the eye E to change the optical path length of the measurement light LM. In particular, when the measured object is not a living body part, the optical path length difference can be changed by moving the measured object in the depth direction (z direction).

  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.

  It is also possible to transmit / receive this program through a network such as the Internet or a LAN.

DESCRIPTION OF SYMBOLS 1 Ophthalmologic observation apparatus 2 Fundus camera unit 2A Optical system drive part 10 Illumination optical system 30 Shooting optical system 31 Focus lens 31A Focus drive part 41 Optical path length change part 42 Galvano scanner 43 Focus lens 43A OCT focus drive part 50 Alignment Optical system 60 Focus optical system 100 OCT unit 101 Light source unit 105 Optical attenuator 106 Polarization adjuster 115 CCD image sensor 200 Arithmetic control unit 210 Control unit 211 Main control unit 2111 Display control unit 2112 Measurement control unit 2113 Alignment control unit 2114 Focus Control unit 2115 Tracking control unit 212 Storage unit 220 Image formation unit 230 Image processing unit 231 Three-dimensional image formation unit 232 Cross-sectional image formation unit 233 Image displacement calculation unit 234 Depth position calculation unit 235 Eye displacement acquisition unit 236 Image alignment 241 display unit 242 operation unit E subject's eye Ef fundus LM measurement light LR reference light LC interference light

Claims (2)

An optical system for optical coherence tomography;
A three-dimensional image acquisition unit that sequentially acquires a three-dimensional image of the eye based on data sequentially acquired by the optical system by repeatedly performing optical coherence tomography on a three-dimensional region of the eye;
A cross-sectional image forming unit that sequentially forms front cross-sectional images based on the three-dimensional images sequentially acquired by the three-dimensional image acquisition unit;
A display control unit that displays a moving image of a front cross-sectional image sequentially formed by the cross-sectional image forming unit;
A measurement control unit that causes the optical system to perform optical coherence tomography for a cross-sectional position designated via an operation unit with respect to a front cross-sectional image displayed on the display unit;
The display control unit displays information indicating a cross section of the front cross-sectional image formed by the cross-sectional image forming unit together with the front cross-sectional image. The cross-sectional image forming unit forms two or more front cross-sectional images corresponding to two or more cross-sections having different depth positions based on the three-dimensional images sequentially acquired by the three-dimensional image acquisition unit,
The ophthalmic observation apparatus according to claim 1, wherein the display control unit displays the two or more front cross-sectional images as moving images and displays information indicating the two or more cross-sections.