JP2014166199A - Fundus analysis device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new index based on an image acquired by performing optical coherence tomography measurement for the eyeground.SOLUTION: A fundus analysis device includes a storage part and an analysis part. Sectional data on a peripheral area of discus nervi optici, which are acquired by optical coherence tomography measurement for the eyeground, are stored in the storage part. The analysis part determines an index for evaluating a form of the eyeground, on the basis of the two or more sectional data positioned in a different direction with respect to the discus nervi optici.

Description

  The present invention relates to a fundus analysis apparatus for analyzing a fundus image acquired 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, an apparatus for forming an image of the fundus oculi or cornea has been put into practical use.

  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 (signal 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. Note that this technique is also called a spectral domain.

  In Patent Document 2, a plurality of two-dimensional cross-sectional images in the horizontal direction are formed by scanning (scanning) the signal light in the horizontal direction (x direction) and the vertical direction (y direction). A technique for acquiring and imaging three-dimensional cross-sectional information of a measurement range is disclosed. As this three-dimensional imaging, for example, a method of displaying a plurality of cross-sectional images side by side in a vertical direction (called stack data) or rendering a volume data (voxel data) based on the stack data to produce a three-dimensional image There is a method of forming.

  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 traveling direction of light is obtained by irradiating the object to be measured with light having a predetermined beam diameter, and analyzing the component of interference light obtained by superimposing the reflected light and the reference light. An OCT apparatus for forming an image of an object to be measured in a cross-section orthogonal to is described. Such an OCT apparatus is called a full-field type or an en-face 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), and the like were used as devices for observing the eye to be examined (for example, Patent Document 6, Patent Document 7, and Patent Document). 8). A fundus camera is a device that shoots the fundus by illuminating the subject's eye with illumination light and receiving the fundus reflection light. 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.

  In the ophthalmologic diagnosis, various indexes for evaluating the presence and degree of disease are used. Major indicators include visual acuity value, eye refractive power, intraocular pressure value, and axial length. In addition, as an index derived by analyzing the image, the ratio (C / D ratio) between the diameter of the optic disc depression (Cup) and the diameter of the optic disc (Disc), the optic disc margin (Rim) (R / D ratio) between the width of the optic nerve and the diameter of the optic disc (see, for example, Patent Document 9). In recent years, with the spread of OCT, an index derived by analyzing an OCT image has attracted attention. As an example, there is an index obtained by retinal layer thickness analysis or drusen analysis (see, for example, Patent Document 10).

JP 11-325849 A JP 2002-139421 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 JP 2008-154950 A Japanese Patent Laid-Open No. 2011-24930

  An object of the present invention is to provide a new index based on an image acquired by OCT measurement of the fundus.

In order to achieve the above object, the invention according to claim 1 is different from a storage unit that stores cross-sectional data of a peripheral region of the optic disc acquired by optical coherence tomography measurement with respect to the fundus, with respect to the optic disc. The fundus analysis apparatus includes an analysis unit that obtains an index for evaluating a fundus morphology based on two or more cross-sectional data positioned in a direction.
The invention according to claim 2 is the fundus analysis apparatus according to claim 1, wherein the analysis unit obtains the index based on one or more sets of cross-sectional data corresponding to opposite positions with respect to the nipple center. It is characterized by that.
A third aspect of the present invention is the fundus analysis apparatus according to the second aspect, wherein the surrounding region includes a circular region centered on the center of the nipple, and the analysis unit includes the circular region as a plurality of portions. An area dividing unit that equally divides into areas is included, and the index is obtained based on cross-sectional data included in a partial area corresponding to the opposite position with respect to the nipple center among the plurality of partial areas.
The invention according to claim 4 is the fundus analysis apparatus according to claim 3, wherein the cross-sectional data includes a cross-sectional image in the surrounding region, and the analysis unit analyzes the cross-sectional image, and A position acquisition unit that acquires a predetermined position of the fundus in the height direction of the cross-sectional image, an average value calculation unit that calculates an average value of the predetermined position in the partial region for each of the plurality of partial regions, and the facing position And an inclination information acquisition unit that obtains, as the index, inclination information indicating the inclination of the fundus in the facing direction based on the average value calculated for the partial region corresponding to
The invention according to claim 5 is the fundus analyzer according to claim 4, wherein the inclination information acquisition unit calculates a new average value based on the plurality of average values calculated for the plurality of partial regions. And calculating a displacement amount of each of the plurality of average values with respect to the new average value, and obtaining the inclination information based on the displacement amount.
The invention according to claim 6 is the fundus analysis apparatus according to claim 4 or claim 5, wherein the analysis unit is configured to indicate an inclination distribution of the fundus in the circular region based on the inclination information. An inclination distribution information creation unit for creating distribution information is included.
The invention according to claim 7 is the fundus analysis apparatus according to claim 6, wherein display information obtained by color-coding the fundus tilt distribution in the circular region is displayed on the display unit based on the tilt distribution information. It has a display control part.
The invention according to claim 8 is the fundus analysis apparatus according to claim 6, wherein display information indicating a direction in which the inclination of the fundus is maximum in the circular region is displayed on the display unit based on the inclination distribution information. It has a display control part to display.
The invention according to claim 9 is the fundus analysis apparatus according to claim 7 or claim 8, wherein the storage unit stores a fundus front image indicating a surface form of the fundus, and the display control unit includes: The display information is displayed so as to overlap the fundus front image.
The invention described in claim 10 is the fundus analyzer according to claim 9, wherein the fundus front image is obtained by irradiating the fundus with light and acquiring the fundus front image based on detection data of the fundus reflection light. It has the part.
The invention according to claim 11 is the fundus analysis apparatus according to any one of claims 1 to 10, wherein the cross-sectional data is a cross-sectional form of a three-dimensional region including the optic nerve head and its surrounding region. It is a three-dimensional cross-sectional image showing
A twelfth aspect of the present invention is the fundus analysis apparatus according to any one of the second to tenth aspects, wherein the cross-sectional data includes a cross-sectional form of a three-dimensional region including the optic nerve head and its surrounding region. The analysis unit includes a nipple center specifying unit that analyzes the three-dimensional cross-sectional image and specifies a nipple center, and obtains the index based on the specified nipple center. And
A thirteenth aspect of the present invention is the fundus analysis apparatus according to the eleventh or twelfth aspect of the present invention, wherein the three-dimensional cross-sectional image is acquired by performing optical coherence tomography measurement on the three-dimensional region. It has a two-dimensional cross-sectional image acquisition unit.
The invention according to claim 14 is the fundus analysis apparatus according to any one of claims 3 to 10, wherein by performing optical coherence tomography measurement on the circular region, the circular region is measured. It has a two-dimensional cross-sectional image acquisition part which acquires the two-dimensional cross-sectional image which shows a cross-sectional form, It is characterized by the above-mentioned.
The invention according to claim 15 is the fundus analysis apparatus according to any one of claims 1 to 14, wherein the storage unit associates the range of the index with the degree of disease. Corresponding information is stored, and the analysis unit includes a disease determination unit that determines the degree of the disease based on the obtained index and the correspondence information.

  According to the present invention, it is possible to provide a new index based on an image acquired by OCT measurement of the fundus.

It is a schematic diagram showing an example of composition of a fundus analysis device concerning an embodiment. It is a schematic diagram showing an example of composition of a fundus analysis device concerning an embodiment. It is a schematic block diagram showing an example of composition of a fundus analysis device concerning an embodiment. It is a schematic block diagram showing an example of composition of a fundus analysis device concerning an embodiment. It is the schematic for demonstrating the process which the fundus analyzer which concerns on embodiment performs. It is the schematic for demonstrating the process which the fundus analyzer which concerns on embodiment performs. It is the schematic for demonstrating the process which the fundus analyzer which concerns on embodiment performs. It is the schematic for demonstrating the process which the fundus analyzer which concerns on embodiment performs. It is the schematic for demonstrating the process which the fundus analyzer which concerns on embodiment performs. It is the schematic for demonstrating the process which the fundus analyzer which concerns on embodiment performs. It is the schematic for demonstrating the process which the fundus analyzer which concerns on embodiment performs. It is the schematic for demonstrating the process which the fundus analyzer which concerns on embodiment performs. It is the schematic for demonstrating the process which the fundus analyzer which concerns on embodiment performs. It is a flowchart showing the operation example of the fundus analysis apparatus which concerns on embodiment.

  An example of an embodiment of a fundus analysis apparatus according to the present invention will be described in detail with reference to the drawings. The fundus analysis apparatus according to the present invention forms a two-dimensional cross-sectional image or a three-dimensional cross-sectional image of the fundus using OCT. In this specification, images acquired by OCT may be collectively referred to as OCT images. 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. In particular, the fundus analysis apparatus according to the embodiment can acquire an OCT image of the fundus using the spectral domain OCT technique, as in the apparatus disclosed in Patent Document 5, and the fundus front image by optical measurement. Can be obtained. It should be noted that the configuration according to the present invention can be applied to a fundus analysis apparatus using a type other than the spectral domain, for example, a swept source OCT technique. In this embodiment, an apparatus combining an OCT apparatus and a fundus camera will be described in detail. However, a fundus front image is acquired using a fundus photographing apparatus other than the fundus camera, for example, an SLO, a slit lamp, or an ophthalmic surgical microscope. It is possible. In addition, the configuration according to this embodiment can be incorporated into a single OCT apparatus.

  The fundus analysis apparatus according to the embodiment provides a new index serving as a diagnostic material for the eye to be examined based on an image acquired by performing optical coherence tomography measurement of the fundus. This index indicates the tilted state (sometimes referred to as the nipple tilt) of the vicinity of the optic disc. It is known that the nipple inclination occurs due to the nasal bulge and ear-side flattening associated with myopia, and that the degree of myopia and the nipple diameter are proportional to each other in high myopia. In addition, it has been pointed out that glaucoma is increasing in myopic eyes, and that in the glaucoma eyes, periapical choroidal atrophy increases with nipple inclination, which is related to visual field impairment. Thus, quantification of the nipple inclination is considered necessary for understanding the pathological condition.

[Constitution]
As shown in FIGS. 1 and 2, the fundus analysis 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 acquiring a two-dimensional image (fundus front image) representing the surface form of the fundus oculi Ef of the eye E to be examined. The fundus front 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 may be, for example, a color image obtained by flashing visible light, or a monochrome still image using near infrared light or visible light as illumination light. The fundus camera unit 2 may be configured to be able to acquire images other than these, such as a fluorescein fluorescent image, an indocyanine green fluorescent image, a spontaneous fluorescent image, and the like.

  The retinal camera unit 2 is provided with a chin rest and a forehead support for supporting the subject's face. 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 photographing optical system 30 guides the fundus reflection light of the illumination light to an imaging device (CCD image sensor (sometimes simply referred to as a CCD) 35, 38). The imaging optical system 30 guides the signal light from the OCT unit 100 to the fundus oculi Ef and guides the signal light passing through the fundus oculi Ef to the OCT unit 100.

  The observation light source 11 of the illumination optical system 10 is configured by, for example, a halogen lamp or an LED (Light Emitting Diode). The light (observation illumination light) output from the observation light source 11 is reflected by the reflection mirror 12 having a curved reflection surface, passes through the condensing lens 13, passes through the visible cut filter 14, and is converted into near infrared light. Become. Further, the observation illumination light is once converged in the vicinity of the photographing light source 15, reflected by the mirror 16, and passes through the relay lenses 17 and 18, the diaphragm 19 and the relay lens 20. Then, the observation illumination light is reflected at the peripheral portion (region around the hole portion) of the aperture mirror 21, passes through the dichroic mirror 46, and is refracted by the objective lens 22 to illuminate the fundus oculi Ef.

  The fundus reflection light of the observation illumination light is refracted by the objective lens 22, passes through the dichroic mirror 46, passes through the hole formed in the central region of the perforated mirror 21, passes through the dichroic mirror 55, and is a focusing lens. It is reflected by the mirror 32 via 31. Further, the fundus reflection light passes through the half mirror 39A, is reflected by the dichroic mirror 33, and forms an image on the light receiving surface of the CCD image sensor 35 by the condenser lens. The CCD image sensor 35 detects fundus reflected light at a predetermined frame rate, for example. On the display device 3, an image (observation image) based on fundus reflection light detected by the CCD image sensor 35 is displayed. When the photographing optical system 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 or an LED. The light (imaging illumination light) output from the imaging light source 15 is applied to the fundus oculi Ef through the same path as the observation illumination light. The fundus reflection light of the imaging illumination light is guided to the dichroic mirror 33 through the same path as that of the observation illumination light, passes through the dichroic mirror 33, is reflected by the mirror 36, and is reflected by the condenser lens 37 of the CCD image sensor 38. An image is formed on the light receiving surface. On the display device 3, an image (captured image) based on fundus reflection light detected by the CCD image sensor 38 is displayed. Note that the display device 3 that displays the observation image and the display device 3 that displays the captured image may be the same or different. In addition, when similar imaging is performed by illuminating the eye E with infrared light, an infrared captured image is displayed.

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

  A part of the light output from the LCD 39 is reflected by the half mirror 39A, reflected by the mirror 32, passes through the focusing lens 31 and the dichroic mirror 55, passes through the hole of the perforated mirror 21, and reaches the dichroic. The light passes through the mirror 46, is refracted by the objective lens 22, and is projected onto the fundus oculi Ef.

  By changing the display position of the fixation target on the screen of the LCD 39, the fixation position of the eye E can be changed. As the fixation position of the eye E, for example, a position for acquiring an image centered on the macular portion of the fundus oculi Ef, or a position for acquiring an image centered on the optic disc as in the case of a conventional fundus camera And a position for acquiring an image centered on the fundus center between the macula and the optic disc. 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 fundus reflection light of the focus light is detected by the CCD image sensor 35 through the same path as the cornea reflection light of the alignment light. A light reception image (split index) by the CCD image sensor 35 is displayed on the display device 3 together with the observation image. The arithmetic and control unit 200 analyzes the position of the split index and moves the focusing lens 31 and the focus optical system 60 to perform focusing as in the conventional case (autofocus function). Alternatively, focusing may be performed manually while visually checking the split indicator.

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

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

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

[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 low-coherence light into reference light and signal light, and generates interference light by causing interference between the signal light passing through the fundus oculi Ef and the reference light passing through the reference optical path. It is configured to detect spectral components. This detection result (detection signal) is sent to the arithmetic control unit 200.

  In the case of a swept source type OCT apparatus, a wavelength swept light source is provided instead of a light source that outputs a low coherence light source, and an optical member that spectrally decomposes interference light is not provided. In general, for the configuration of the OCT unit 100, a known technique according to the type of optical coherence tomography can be arbitrarily applied.

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

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

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

  The reference light LR is guided by the optical fiber 104 and reaches the optical attenuator (attenuator) 105. The optical attenuator 105 automatically adjusts the amount of the reference light LR guided to the optical fiber 104 under the control of the arithmetic control unit 200 using a known technique. The reference light LR whose light amount has been adjusted by the optical attenuator 105 is guided by the optical fiber 104 and reaches the polarization adjuster (polarization controller) 106. 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 signal light LS generated by the fiber coupler 103 is guided by the optical fiber 107 and converted into a parallel light beam by the collimator lens unit 40. Further, the signal light LS reaches the dichroic mirror 46 via the optical path length changing unit 41, the galvano scanner 42, the focusing lens 43, the mirror 44, and the relay lens 45. The signal light LS is reflected by the dichroic mirror 46, is refracted by the objective lens 22, and is applied to the fundus oculi Ef. The signal light LS is scattered (including reflection) at various depth positions of the fundus oculi Ef. The backscattered light of the signal light LS from the fundus oculi Ef travels in the same direction as the forward path in the reverse direction, is guided to the fiber coupler 103, and reaches the fiber coupler 109 via the optical fiber 108.

  The fiber coupler 109 causes the backscattered light of the signal light LS to interfere with the reference light LR that has passed through the optical fiber 104. The interference light LC generated thereby is guided by the optical fiber 110 and emitted from the emission end 111. Further, the interference light LC is converted into a parallel light beam by the collimator lens 112, 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, and the reflector 67. Movement control, movement control of the focus optical system 60, movement control of the optical path length changing unit 41, operation control of the galvano scanner 42, 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 fundus analyzer 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 fundus analysis apparatus 1 will be described with reference to FIGS. 3 and 4.

(Control part)
The control system of the fundus analysis 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. In particular, the main control unit 211 controls the focusing drive unit 31A, the optical path length changing unit 41 and the galvano scanner 42 of the fundus camera unit 2, and further the light source unit 101, the optical attenuator 105 and the polarization adjuster 106 of the OCT unit 100. To do.

  The focusing drive unit 31A moves the focusing lens 31 in the optical axis direction. Thereby, the focus position of the photographic optical system 30 is changed. The main control unit 211 can also move an optical system provided in the fundus camera unit 2 in a three-dimensional manner by controlling an optical system drive unit (not shown). This control is used in alignment and tracking. Tracking is to move 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. Tracking is a function of maintaining a suitable positional relationship in which the alignment and focus are achieved by causing the position of the apparatus optical system to follow the eye movement.

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

(Memory part)
The storage unit 212 stores various data. Examples of data stored in the storage unit 212 include eye information to be examined. The eye information includes information about the subject such as patient ID and name, and information about the eye such as left / right eye identification information. The storage unit 212 stores various programs and data for operating the fundus analysis apparatus 1.

  As illustrated in FIG. 4, the storage unit 212 stores cross-sectional data 2121, a fundus front image 2122, and correspondence information 2123.

(Cross section data)
The cross-sectional data 2121 includes data indicating the peripheral region of the optic disc acquired by OCT measurement for the fundus oculi Ef. The surrounding area is an area in the vicinity of the optic nerve head of the fundus oculi Ef, and its shape and size are arbitrarily set. The cross-sectional data 2121 may include an optic disc area.

  The cross-sectional data 2121 includes data on the examination target part for obtaining a target index (nipple inclination). The inspection target part is, for example, a circular region, the center of which is set to the center of the optic nerve head (papillae center), and the diameter thereof is set to 3.4 mm. This circular region means that the shape of the fundus oculi Ef viewed from the front side is circular, and in a three-dimensional coordinate system (xyz coordinate system), a cylindrical shape having a predetermined diameter with the nipple center as an axis. It is an area. This diameter is set so that the circular region is located outside the edge diameter (Disc diameter) of the optic disc.

  Examples of the cross-sectional data 2121 include a three-dimensional cross-sectional image obtained by three-dimensional scanning (described later) of the optic nerve head and the surrounding area, and a two-dimensional cross-sectional image obtained by circular scanning (described later) of the surrounding area. In this circular scan, its center is set to the nipple center and its diameter is set to 3.4 mm.

  The cross-sectional data 2121 is not limited to a cross-sectional image. The cross-sectional data 2121 is data in an arbitrary form necessary for obtaining the nipple inclination. More specifically, the cross-sectional data 2121 is initial data (cross-sectional image) or intermediate generation data in the process for obtaining the nipple inclination from the cross-sectional image of the fundus oculi Ef. As will be described later, in this embodiment, the analysis unit 231 derives the nipple inclination, so the cross-sectional data 2121 may be a cross-sectional image or data generated by processing until the nipple inclination is obtained. In this embodiment, since the fundus analysis apparatus 1 itself acquires a cross-sectional image and the analysis unit 231 obtains the nipple inclination, it is natural to use the cross-sectional image as the cross-sectional data 2121. It is also possible to execute the processing by the unit 231 halfway and use the intermediate generation data as the cross-sectional data 2121.

(Fundus front image)
The fundus front image 2122 is an image showing the surface form of the fundus oculi Ef. The fundus front image 2122 is acquired by a fundus imaging apparatus such as a fundus camera, SLO, or a slit lamp. In this embodiment, an image acquired by the fundus camera unit 2 is stored as a fundus front image 2122.

(Correspondence information)
The correspondence information 2123 is used to determine the disease of the eye E based on the nipple inclination. The correspondence information 2123 associates the range of nipple inclination with the degree of disease. The target diseases include diseases that are associated with nipple inclination, such as myopia and glaucoma, or diseases that are assumed to be associated. The degree of the disease includes the presence or absence of the disease and the degree of progression of the disease. The degree of disease is defined, for example, by other diagnostic methods (a refraction test that measures the degree of myopia, a visual field test that measures the degree of glaucoma, etc.).

  As an example of the correspondence information 2123 related to myopia, the first range of nipple inclination is associated with the first range of myopia (no myopia), and the second range of nipple inclination and the second range of myopia A range in which a range (weak myopia) is associated with a third range of nipple inclination and a third range of near myopia (intensity myopia) can be applied.

  As an example of the correspondence information 2123 regarding glaucoma, the first range of nipple inclination and the first range of glaucoma degree (no glaucoma) are associated, and the second range of nipple inclination and the second range of glaucoma degree The range (mild) is associated with the third range of nipple inclination and the third range (moderate) of the degree of glaucoma, and the fourth range of nipple inclination and the fourth range of glaucoma. Can be applied in association with the range (severity).

(Image forming part)
The image forming unit 220 forms image data of a two-dimensional cross-sectional image of the fundus oculi Ef based on the detection signal 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 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 described above. In this specification, “image data” and “image” based thereon may be identified.

(Data processing part)
The data processing unit 230 performs various types of image processing and analysis processing on the two-dimensional cross-sectional image formed by the image forming unit 220. For example, the data processing unit 230 executes various correction processes such as image brightness correction. In addition, the data processing unit 230 performs various types of image processing and analysis processing on an image (fundus front image, anterior eye image, etc.) obtained by the fundus camera unit 2.

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

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

(Analysis Department)
As shown in FIG. 3, the data processing unit 230 is provided with an analysis unit 231. The analysis unit 231 obtains an index of the fundus oculi Ef based on the cross-sectional data 2121 stored in the storage unit 212. In this embodiment, a two-dimensional sectional image or a three-dimensional sectional image is used as the sectional data 2121.

  The cross-sectional data 2121 includes two or more cross-sectional data located in different directions with respect to the optic disc. The analysis unit 231 obtains the nipple inclination in the direction defined by the position of the cross section data based on the two or more cross section data. In this case, each cross-sectional data is, for example, an OCT image corresponding to one A line.

  As an example of this processing, the analysis unit 231 obtains the nipple inclination in the direction defined by the position of the cross-section data based on one or more sets of cross-section data corresponding to the opposing positions with respect to the nipple center. More specifically, two cross-sectional data are located on an arbitrary line segment passing through the nipple center. These cross-sectional data correspond to “a set of cross-sectional data corresponding to the opposite positions with respect to the nipple center”. The nipple inclination calculated | required by this one set is an inclination in the direction along the said line segment. In addition, it is possible to obtain one value of the nipple inclination by comprehensively considering those in the vicinity of such a set (described later).

  In addition, the cross-sectional data used for the calculation of the nipple inclination is not limited to data existing at the opposite position with respect to the nipple center. For example, based on cross-sectional data existing at a position orthogonal to the nipple center (for example, a position at 0 o'clock and a position at 3 o'clock), information indicating the torsion of inclination in two directions orthogonal to each other can be obtained. Further, based on the cross-sectional data in any two directions, the nipple inclination in a direction between these two directions (for example, an intermediate direction) can be estimated.

  A specific example of the analysis unit 231 that performs the above processing is shown in FIG. The analysis unit 231 of this example includes a nipple center specifying unit 2311, a region dividing unit 2312, a layer position acquiring unit 2313, an average value calculating unit 2314, an inclination information acquiring unit 2315, an inclination distribution information creating unit 2316, A disease determination unit 2317.

(Nipple center specific part)
The nipple center specifying unit 2311 functions when obtaining an index based on a three-dimensional cross-sectional image. A three-dimensional cross-sectional image is an image showing a cross-sectional form of a three-dimensional region including the optic disc and its surrounding region. The nipple center specifying unit 2311 analyzes the three-dimensional cross-sectional image and specifies the nipple center. This process is executed as follows, for example.

  First, the nipple center specifying unit 2311 analyzes the three-dimensional cross-sectional image and specifies an image region corresponding to the edge of the optic nerve head. Considering that the optic disc is a deep depression in the + z direction of the fundus surface, this processing includes, for example, a process of specifying an image region (fundus surface region) corresponding to the fundus surface in a three-dimensional cross-sectional image, This includes a process of specifying a nipple area that is depressed in the + z direction in the fundus surface area (image area) and a process of specifying an image area (edge area) corresponding to the −z side end of the nipple area.

  Next, the nipple center specifying unit 2311 approximates the shape of the specified edge region to a circle or an ellipse. Subsequently, the nipple center specifying unit 2311 obtains the center of the acquired approximate circle or approximate ellipse. This center is used as the nipple center in this three-dimensional cross-sectional image.

  The process for obtaining the nipple center is not limited to the automatic process. For example, when the user designates the nipple center with respect to the display image of the fundus front image 2122, the nipple center identifying unit 2311 identifies the position of the three-dimensional cross-sectional image corresponding to the designated position, and this specified position is the target position. It can be configured to be used as a nipple center. In addition, the nipple center specifying unit 2311 can correct the position designated by the user based on the analysis result of the three-dimensional cross-sectional image.

  Further, since a fixation position for measuring the optic disc is applied during OCT measurement, the fixation position information can be stored in the storage unit 212 in association with the three-dimensional cross-sectional image. In that case, the center of the nipple can be specified with reference to the fixation position information.

  The nipple center specifying unit 2311 sends information on the specified nipple center, for example, coordinate information indicating a position corresponding to the nipple center in the three-dimensional cross-sectional image, to the region dividing unit 2312 and the layer position acquiring unit 2313.

(Region division)
The area dividing unit 2312 divides an image area applied to derivation of the nipple inclination into a plurality of partial areas. In this embodiment, a circular region having a predetermined diameter centered on the nipple center is applied, and the region dividing unit 2312 equally divides this circular region into a plurality of partial regions.

  When determining the nipple inclination from the three-dimensional cross-sectional image, for example, the region dividing unit 2312 uses a circular area in the three-dimensional cross-sectional image based on the coordinates of the nipple center input from the nipple center specifying unit 2311 and a preset diameter. (Cylindrical region) is set, and this circular region is equally divided into a plurality of partial regions along the circumference.

  When obtaining the nipple inclination from the two-dimensional cross-sectional image acquired by circular scanning around the center of the nipple, the region dividing unit 2312 follows the circumference of the circular region (cylindrical region) indicated by the two-dimensional cross-sectional image. Divide equally into multiple partial areas.

  Examples of the circular area division mode are shown in FIGS. 5A to 5C. In FIG. 5A, the symbol D indicates the optic nerve head (edge) of the fundus oculi Ef, and the symbol C indicates the center of the nipple. Reference numeral R indicates a circular region. The circular region R is a region set around the optic disc D and centered on the nipple center C.

  In FIG. 5B, reference symbol G1 indicates a two-dimensional cross-sectional image of the circular region R. The two-dimensional cross-sectional image G1 draws a cylindrical region corresponding to the circular region R. Here, the upper end of the two-dimensional sectional image G1 corresponds to the circular region R shown in FIG. 5A. Reference symbol C indicates a cylindrical axis of the two-dimensional sectional image G1 corresponding to the nipple center C of FIG. 5A. Here, since the center of the nipple and the cylindrical shaft correspond one-to-one, these are denoted by the same reference numerals.

  In FIG. 5C, a symbol G2 indicates a two-dimensional cross-sectional image obtained by cutting out the cylindrical two-dimensional cross-sectional image G1 shown in FIG. 5B. The two-dimensional cross-sectional image G2 is obtained by cutting and flattening the two-dimensional cross-sectional image G1 of FIG. 5B along the z direction at the nose side position. As is commonly used, N indicates the nasal side, S indicates the upper side (Superior), T indicates the ear side (Temporal), and I indicates the lower side (Inferior).

  The region dividing unit 2312 equally divides such a two-dimensional cross-sectional image G2 (or two-dimensional cross-sectional image G1) into a plurality of partial regions Hi (i = 1 to n). As shown in FIG. 5C, the division mode is to divide the two-dimensional cross-sectional image G2 into n equal parts in the circumferential direction. In other words, the region dividing unit 2312 equally divides the two-dimensional cross-sectional image G2 so that the circular region R shown in FIG. 5A is equally divided into n.

  The area dividing unit 2312 sends information indicating the division mode of the two-dimensional cross-sectional image G2, for example, coordinate information indicating the equally divided points, to the average value calculating unit 2314.

(Layer position acquisition unit)
The layer position acquisition unit 2313 analyzes the cross-sectional image to acquire the position of the predetermined layer of the fundus oculi Ef in the height direction (z direction) of the cross-sectional image. In this embodiment, at least the processing by the layer position acquisition unit 2313 is performed on the two-dimensional cross-sectional image (see the two-dimensional cross-sectional image G2 in FIG. 5C) that has been processed by the region dividing unit 2312.

  The predetermined layer is an anatomically identified tissue (inner border membrane, nerve fiber layer, ganglion cell layer, inner reticular layer, inner granule layer, outer reticular layer, outer granule layer, outer border membrane, photoreceptor layer, Retinal pigment epithelium layer, choroid, sclera, etc.) or a layer characteristically depicted in an image (a layer with the highest luminance, an Ath layer counted in the depth direction from the fundus surface, etc.) It may be. In this embodiment, it is assumed that the retinal pigment epithelium layer is applied.

  An example of processing executed by the layer position acquisition unit 2313 will be described with reference to FIG. First, the layer position acquisition unit 2313 performs the pixel position j (j = 1 to m) in the horizontal direction (xy direction, that is, the direction orthogonal to the z direction) of the two-dimensional sectional image G2, that is, the position j of each A line. , The pixel corresponding to the retinal pigment epithelial layer L at the pixel position j is specified. This processing is executed by a known method such as pixel value threshold processing. Such processing for specifying the layer position is called segmentation or the like.

  Next, the layer position acquisition unit 2313 obtains the height position Pj of the pixel specified for each pixel position j. The definition method of this height position is arbitrary. For example, the height position is defined as the number of pixels between the bottom position (the position on the most + z side) of the two-dimensional cross-sectional image G2 and the pixel corresponding to the retinal pigment epithelium layer L in the A line. This height position is defined as the difference between the z coordinate of the base position of the two-dimensional cross-sectional image G2 and the z coordinate value of the pixel corresponding to the retinal pigment epithelium layer L in the A line. This height position is the position of the pixel corresponding to the retinal pigment epithelium layer L (number of pixels, image, etc.) with respect to a predetermined reference pixel (for example, the upper surface of the two-dimensional cross-sectional image G2, the surface of the fundus, other layers) Defined as the distance above, the converted distance to real space, etc.).

  The layer position acquisition unit 2313 sends information indicating the acquired height position of the predetermined layer to the average value calculation unit 2314.

(Average value calculator)
The average value calculation unit 2314 includes information indicating a division mode of the cross-sectional image acquired by the region division unit 2312 into a plurality of partial regions, and information indicating the height position of the predetermined layer acquired by the layer position acquisition unit 2313. Are entered. The average value calculation unit 2314 calculates the average value of the height positions of the predetermined layers in each partial region. This process is executed by adding a plurality of height positions corresponding to a plurality of A lines (a plurality of pixel positions) included in each partial region, and dividing the sum by the number of the plurality of A lines. The

  FIG. 7 schematically shows the calculation result by the average value calculation unit 2314 regarding the example shown in FIG. Each Qi (i = 1 to n) indicates the average value of the height position Pj of the retinal pigment epithelium layer L calculated by the average value calculation unit 2314 for the corresponding partial region Hi.

  The average value calculation unit 2314 sends information indicating the calculation result of the height position of the predetermined layer regarding the plurality of partial areas to the inclination information acquisition unit 2315.

(Tilt information acquisition unit)
The inclination information acquisition unit 2315 indicates the inclination of the fundus oculi Ef in the facing direction based on the average value of the height positions calculated by the average value calculating unit 2314 for a pair of partial regions corresponding to the facing position with respect to the nipple center. Find information (nipple tilt). When the height positions of the opposed partial areas are different, the peripheral area of the optic nerve head is inclined in this facing direction. Further, the greater the difference in height position, the greater the inclination. The inclination information is an index indicating the degree of such inclination.

  An example of the process executed by the inclination information acquisition unit 2315 will be described with reference to FIGS. 8 and 9. FIG. 8 shows a two-dimensional cross-sectional image G1 (see FIG. 5B) as seen from the front side of the fundus. As shown in FIG. 5B, the two-dimensional sectional image G1 includes a plurality of partial regions Hi (i = 1 to n). In this example, it is assumed that the number of partial regions Hi is an even number (n = 2k). As shown in FIG. 5C, the plurality of partial areas Hi are ordered clockwise starting from the nose side (N).

  In such a setting, the partial area Hi and the partial area H (k + i) are associated (i = 1 to k). As a specific example, FIG. 8 shows an arrow D1 indicating a facing direction between the partial region H1 and the partial region H (k + 1), an arrow D2 indicating a facing direction between the partial region H2 and the partial region H (k + 2), and An arrow Dk indicating the facing direction between the partial region Hk and the partial region H (2k) is shown.

  As described above, the average value calculation unit 2314 calculates the average value Qi of the height position Pj of the retinal pigment epithelium layer L in each partial region Hi (i = 1 to n). The inclination information acquisition unit 2315 first calculates the average value Q of the plurality of average values Qi. This process is performed by adding a plurality of average values Qi and dividing by the number (n) of partial areas Hi. The average value Q corresponds to a “new average value”.

  Next, the inclination information acquisition unit 2315 calculates the displacement amount ΔQi of each average value Qi with respect to the new average value Q. The calculation method of the displacement amount ΔQi is arbitrary. As a specific example, by subtracting a new average value Q from each average value Qi, a displacement amount ΔQi in the partial region Hi is obtained: ΔQi = Qi−Q. FIG. 9 shows an example of the displacement amount ΔQi acquired for the plurality of partial regions Hi (i = 1 to n) in this way. The displacement amount ΔQi is an example of inclination information, and indicates an inclination state in the direction of the corresponding partial area Hi (that is, the direction of the partial area Hi with respect to the nipple center C).

  Furthermore, the inclination information acquisition unit 2315 can obtain inclination information based on the displacement amounts ΔQi (i = 1 to n) obtained for the plurality of partial regions Hi. As a specific example, the inclination information acquisition unit 2315 for each facing direction Di (i = 1 to k), a pair of displacement amounts ΔQi and ΔQ (in a pair of partial regions Hi and H (k + i) located in the facing direction Di. The difference Ti of k + i) is calculated. This difference Ti is an example of inclination information and indicates an inclination state in the facing direction Di.

  As an example of processing for calculating the inclination information Ti, Ti = ΔQ (k + i) −ΔQi can be defined for i <k + i. The inclination information Ti obtained by this processing represents the height position of the partial region H (k + i) with reference to the displacement amount ΔQi of the partial region Hi on the side with a smaller index i. Conversely, it can be defined as Ti = ΔQi−ΔQ (k + i). It is also possible to obtain the degree of inclination by defining Ti = | ΔQ (k + i) −ΔQi |, and obtain the direction of inclination by comparing the magnitudes of these displacement amounts ΔQ (k + i) and ΔQi. It is.

  The inclination information acquisition unit 2315 sends the inclination information acquired for each partial region Hi or each facing direction Di to the inclination distribution information creation unit 2316. Here, the inclination information includes information indicating the degree of inclination (inclination angle or the like) and information indicating the inclination direction.

(Inclination distribution information creation part)
The inclination distribution information creation unit 2316 creates inclination distribution information indicating the distribution of the inclination of the fundus oculi Ef in the circular region R based on the inclination information input from the inclination distribution information creation unit 2315. As described above, the inclination information includes information indicating the degree of inclination (inclination angle information) and information indicating the inclination direction (inclination direction information) regarding each partial region Hi or each facing direction Di. . The slope distribution information creation unit 2316 creates slope distribution information, for example, by mapping slope angle information acquired for a plurality of partial regions Hi or a plurality of facing directions Di based on the slope direction information.

  The main control unit 211 causes the display unit 241 to display information based on the inclination distribution information. Hereinafter, examples of such display information will be described.

  A first example of display information is shown in FIG. The display information 1000 includes a nipple inclination map 1100, a maximum inclination mark 1200, and a color chart 1300. The nipple inclination map 1100 is display information in which the distribution state of the nipple inclination in the circular area R is displayed in different colors, and an image area (also indicated by the reference numeral Hi) indicating a plurality of partial areas Hi includes the inclination information (displacement amount ΔQi, It is displayed in a color corresponding to the value of the average value Qi and the like. The correspondence relationship between the value of the inclination information and the display color is presented in the color chart 1300. Note that the color chart 1300 in FIG. 10 associates the value of the displacement amount ΔQi (−300 to +300 pixels) with the display color. In addition, the aspect which represents the value of inclination information is arbitrary. For example, instead of the above color-coded display, it is possible to use a gradation or a display pattern. The maximum inclination mark 1200 indicates an opposing direction in which the nipple inclination is the maximum among a plurality of opposing directions Di. The maximum inclination mark 1200 is displayed as an arrow indicating the downward inclination direction as shown in FIG. In addition, the degree of inclination can be presented by the thickness or color of the arrow.

  A second example of display information is shown in FIG. Display information 2000 includes a nipple inclination map 1100, a maximum inclination mark 1200, and a color chart 1300 similar to those in FIG. The fundus front image 1400 is a display image based on the fundus front image 2122 stored in the storage unit 212. The fundus front image 1400 is superimposed on the nipple inclination map 1100. This superimposed display process is performed by using, for example, a plurality of layers. The alignment of the nipple inclination map 1100 and the fundus front image 1400 is performed, for example, by matching the center position of the circular region R on which the nipple inclination map 1100 is based with the nipple center position in the fundus front image 1400. Done.

(Disease determination unit)
As described above, the storage unit 212 stores correspondence information 2123 in which the range (degree) of the nipple inclination and the degree of disease are associated with each other. The disease determination unit 2317 determines the degree of the disease based on the inclination information (or inclination distribution information obtained therefrom) and the correspondence information 2123. This process is performed, for example, by referring to the correspondence information 2123 to specify the degree of the disease corresponding to the value indicated by the inclination information. Or when the information regarding the direction of the nipple inclination and its distribution state is included in the correspondence information 2123, the degree of the disease can be specified in consideration of the inclination direction information included in the inclination information and the inclination distribution information. In addition, it is possible to determine the degree of the disease based on the left and right tilt information acquired for the left and right eye according to the type of the disease.

  Information indicating the degree of the disease acquired by the disease determination unit 2317 is displayed on the display unit 241 by the main control unit 211. This display content includes information indicating the presence / absence of the assumed disease and the degree of progression.

  A visual field disorder is a disease to be determined. Visual field impairment is caused by glaucoma, for example. Inspection of visual field defects is generally performed by a perimeter. Therefore, it is possible to determine a disease based on the inspection result obtained by the perimeter and the OCT image. That is, the correspondence information 2123 may include information for associating the inspection result obtained by the perimeter with the findings in the OCT image.

  As a first example of disease determination related to visual field impairment, an attention position related to visual field impairment can be acquired based on the direction in which the nipple inclination becomes maximum. The association between the maximum inclination direction and the position of interest is determined based on, for example, the running distribution of nerve fibers in the fundus. The running distribution of nerve fibers is anatomically known. It is also possible to acquire the running distribution of nerve fibers by the OCT apparatus.

  As a second example of disease determination related to visual field impairment, the degree of visual field impairment can be acquired based on the degree of nipple inclination (the magnitude of the inclination angle). The relationship between the magnitude of the tilt angle and the degree of visual field disturbance is acquired based on clinical data.

  It is possible to combine the first example and the second example of disease determination. That is, the disease determination unit 2317 can be configured to acquire the position of interest and the degree of visual field disturbance based on the direction and degree of nipple inclination.

  A specific example of disease determination relating to visual field impairment will be described. In the case of normal-tension glaucoma, in the case of visual field impairment in the fovea or in the vicinity thereof, the inventor shows that the direction of maximum inclination of the nipple is ± 7.5 degrees, that is, substantially horizontal. It was found by. It is assumed that the angle is 0 degree on the ear side and the clockwise direction is the positive direction. Furthermore, in early stage glaucoma with an MD value (obtained by visual field inspection) within −6 dB indicating the degree of visual field deficit, the direction in which the maximum inclination of the nipple is +7.5 degrees and the foveal disorder It was found by the present inventor that there is a significant correlation in the visual field, and that the visual field of the upper ear side of the four points at the center 5 degrees in the visual field examination is most susceptible. That is, it is possible to prepare correspondence information 2123 for associating the possibility of visual field disturbance near the fovea with respect to the inclination of the nipple in the direction of +7.5 degrees. Then, the disease determination unit 2317 determines whether the direction of the nipple inclination is +7.5 degrees, and determines that there is a risk of visual field disturbance near the fovea when this condition is satisfied. In addition, it is also possible to determine the degree of visual field disturbance based on the magnitude of the tilt angle.

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

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

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

[Signal light scanning and OCT images]
Here, the scanning of the signal light LS and the OCT image will be described.

  Examples of scanning modes of the signal light LS by the fundus analyzing apparatus 1 include horizontal scanning, vertical scanning, cross scanning, radiation scanning, circular scanning, concentric scanning, and spiral (vortex) scanning. These scanning modes are selectively used as appropriate in consideration of the observation site of the fundus, the analysis target (such as retinal thickness), the time required for scanning, the precision of scanning, and the like.

  The horizontal scan scans the signal light LS in the horizontal direction (x direction). The horizontal scan also includes an aspect in which the signal light LS 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 the vertical scan.

  In the cross scan, the signal light LS is scanned along a cross-shaped trajectory composed of two linear trajectories (straight trajectories) orthogonal to each other. In the radiation scan, the signal light LS 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 signal light LS is scanned along a circular locus. In the concentric scan, the signal light LS 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 helical scan, the signal light LS is scanned along a spiral (spiral) trajectory while gradually reducing (or increasing) the radius of rotation.

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

  By scanning the signal light LS in the above-described manner, a cross-sectional image on the surface stretched by the direction along the scanning line (scanning trajectory) 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.

  A region on the fundus oculi Ef to be scanned with the signal light LS as described above, that is, a region on the fundus oculi Ef to be subjected to OCT measurement is 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 fundus analysis apparatus 1 will be described. FIG. 12 illustrates an example of the operation of the fundus analysis apparatus 1.

(S1: Acquisition of near-infrared moving image)
First, a near-infrared moving image of the fundus oculi Ef is acquired by continuously illuminating the fundus oculi Ef with illumination light from the observation light source 11 (which becomes near-infrared light by the visible cut filter 14). This near-infrared moving image is obtained in real time until the continuous illumination ends.

  A fixation target by the LCD 39 is projected onto the eye E to be examined. The subject is instructed to stare at the fixation target. In this operation example, for example, a fixation position for acquiring an image centered on the optic disc is applied. Further, the focus adjustment for the fundus oculi Ef is executed by projecting the split index.

(S2: OCT measurement)
The main control unit 211 performs OCT measurement on a region including the circular region R around the optic disc. In this OCT measurement, for example, a three-dimensional scan for the optic disc and its surrounding area, or a circular scan for the circular area R is applied.

  The image forming unit 220 forms a two-dimensional cross-sectional image based on data acquired by OCT measurement. When the three-dimensional scan is applied, a plurality of two-dimensional cross-sectional images corresponding to the plurality of scanning lines are formed. The data processing unit 230 forms a three-dimensional cross-sectional image based on these two-dimensional cross-sectional images. When the circular scan is applied, a two-dimensional cross-sectional image along the circular region R is formed. The main control unit 211 causes the storage unit 212 to store the three-dimensional cross-sectional image or the two-dimensional cross-sectional image acquired in this way. These cross-sectional images are examples of the cross-sectional data 2121.

  The main control unit 211 causes the storage unit 212 to store at least one frame of the near-infrared moving image acquired when the OCT measurement is being performed or at timings before and after the OCT measurement. This frame is an example of the fundus front image 2122. Further, after the OCT measurement, the main control unit 211 can control the fundus camera unit 2 to perform color photographing of the fundus oculi Ef, and store the color fundus image acquired thereby in the storage unit 212. This color fundus image is an example of the fundus front image 2122.

(S3: Identification of nipple center)
When the cross-sectional data 2121 to be processed is a three-dimensional cross-sectional image, the nipple center specifying unit 2311 analyzes the three-dimensional cross-sectional image and specifies the nipple center. When the processing target is a two-dimensional cross-sectional image, it is not necessary to perform this processing.

(S4: Division into partial areas)
The area dividing unit 2312 divides the circular area R into a plurality of partial areas Hi along the circumference thereof. When the processing target is a three-dimensional cross-sectional image, the region dividing unit 2312 determines a circular region in the three-dimensional cross-sectional image based on the coordinates of the nipple center input from the nipple center specifying unit 2311 and a preset diameter. R is set, and this circular region R is equally divided into a plurality of partial regions along the circumference. When the processing target is a two-dimensional cross-sectional image, the region dividing unit 2312 equally divides the circular region R indicated by the two-dimensional cross-sectional image into a plurality of partial regions along the circumference.

(S5: Acquisition of layer position)
The layer position acquisition unit 2313 analyzes the cross-sectional image of the circular region R to obtain the height position Pj of the predetermined layer (retinal pigment epithelium layer L) at each pixel position j. In addition, the timing which performs step 4 and step 5 is arbitrary. For example, one of these steps may be performed first, or these steps may be performed in parallel.

(S6: Calculation of average value of layer positions)
The average value calculation unit 2314 calculates the average value Qi of the height position Pj of the predetermined layer (retinal pigment epithelium layer L) in each partial region Hi.

(S7: Acquisition of tilt information)
The inclination information acquisition unit 2315 obtains inclination information indicating the inclination of the fundus oculi Ef in the facing direction Di based on the average value Qi calculated in step 6 for the pair of partial areas Hi corresponding to the facing positions with respect to the nipple center (nipple inclination). )

(S8: Creation of slope distribution information)
The inclination distribution information creation unit 2316 creates inclination distribution information indicating the distribution of the inclination of the fundus oculi Ef in the circular region R based on the inclination information acquired in Step 7.

(S9: Determination of disease)
The disease determination unit 2317 determines the degree of disease of the fundus oculi Ef based on the inclination information acquired in step 7 or the inclination distribution information acquired in step 8 and the correspondence information 2123.

(S10: Display of display information / disease determination result)
Based on the inclination distribution information (and the fundus front image 2122) acquired in step 8, the main control unit 211 causes the display unit 241 to display display information as illustrated in FIGS. 10 and 11, for example. In addition, the main control unit 211 causes the display unit 241 to display the disease determination result in step 9. Thus, this operation example ends.

[Action / Effect]
The operation and effect of the fundus analyzer of the embodiment will be described.

  The fundus analysis apparatus includes a storage unit 212 and an analysis unit 231. The storage unit 212 stores cross-sectional data 2121 of the surrounding area of the optic disc acquired by OCT measurement for the fundus oculi Ef. The cross-sectional data 2121 includes a plurality of cross-sectional data located in a plurality of directions with respect to the optic disc. The analysis unit 231 obtains an index (papillary tilt) for evaluating the form of the fundus oculi Ef based on two or more cross-sectional data located in different directions with respect to the optic disc.

  According to such a fundus analysis apparatus, it is possible to provide a new index based on an image acquired by OCT measurement of the fundus oculi Ef, that is, an index indicating an inclination state around the optic nerve head.

  Note that the fundus analysis apparatus of this embodiment has a function of executing OCT measurement. However, the cross-section data 2121 acquired by another OCT apparatus is received, stored in the storage unit 212, and stored in the analysis unit 231. It is possible to configure a fundus analysis apparatus that performs processing in the above. Examples of such a fundus analyzing apparatus include an information processing apparatus (such as a personal computer) and a fundus photographing apparatus (such as a fundus camera, SLO).

  The analysis unit 231 may be configured to obtain an index based on one or more sets of cross-sectional data corresponding to the opposing positions with respect to the nipple center C. According to this configuration, an index can be obtained for each set of cross-sectional data. The method for combining the cross-sectional data is arbitrary.

  The following configuration can be applied as an example of a combination of cross-sectional data. In this configuration, the peripheral region of the optic disc includes a circular region R centered on the nipple center C. The analysis unit 231 includes an area dividing unit 2312. The area dividing unit 2312 equally divides the circular area R into a plurality of partial areas Hi. The analysis unit 231 obtains an index based on the cross-sectional data included in the partial area Hi corresponding to the facing position Di with respect to the nipple center C among the plurality of partial areas Hi.

  In addition to this, the following configuration can be applied. In this configuration, the cross-sectional data 2121 includes a cross-sectional image in the peripheral region of the optic disc. The analysis unit 231 includes a layer position acquisition unit 2313, an average value calculation unit 2314, and an inclination information acquisition unit 2315. The layer position acquisition unit 2313 analyzes the cross-sectional image to acquire the position Pj of the predetermined layer of the fundus oculi Ef in the height direction of the cross-sectional image. The average value calculation unit 2314 calculates the average value Qi of the position Pj of the predetermined layer in each partial region Hi. The tilt information acquisition unit 2315 obtains tilt information indicating the tilt of the fundus oculi Ef in the facing direction Di based on the average value Qi calculated for the partial region Hi corresponding to the facing position Di. The inclination information is an example of the index. With the tilt information, the tilt of the fundus oculi Ef in the facing direction Di of the peripheral region of the optic disc can be grasped. Note that the layer position acquisition unit 2313 of this embodiment is configured to acquire the position of a predetermined layer of the fundus oculi Ef, but the position acquisition unit of the present invention can be set to an arbitrary height position (a predetermined position of the fundus oculi in the cross-sectional image). ). For example, the position acquisition unit can be configured to acquire a height position having the maximum luminance (intensity) in the cross-sectional image. At this time, it is possible to recognize the pixel corresponding to the noise and exclude the pixel to obtain the position of the maximum luminance.

  The inclination information acquisition unit 2315 may be configured to perform the following processing. First, the inclination information acquisition unit 2315 calculates a new average value Q based on the plurality of average values Qi calculated for the plurality of partial regions Hi. Next, the inclination information acquisition unit 2315 calculates a displacement amount ΔQi of each of the plurality of average values Qi with respect to the new average value Q. Then, the inclination information acquisition unit 2315 obtains the inclination information based on the calculated displacement amount ΔQi.

  The analysis unit 231 may further include an inclination distribution information creation unit 2316. The inclination distribution information creation unit 2316 creates inclination distribution information indicating the distribution of the inclination of the fundus oculi Ef in the circular region R based on the inclination information acquired by the inclination information acquisition unit 2315. Thereby, the distribution of the inclination of the fundus oculi Ef in the peripheral region of the optic disc can be grasped.

  The main control unit 211 can cause the display unit 241 to display display information in which the distribution of the inclination of the fundus oculi Ef in the circular region R is color-coded based on the inclination distribution information. As an example of this display information, there is a nipple inclination map 1100 shown in FIGS. The main control unit 211 that executes this process is an example of a display control unit. Thereby, the distribution of the inclination of the fundus oculi Ef in the region around the optic disc can be visually recognized.

  The main control unit 211 can cause the display unit 241 to display display information indicating the direction in which the inclination of the fundus oculi Ef is maximum in the circular region R based on the inclination distribution information. As an example of this display information, there is a maximum inclination mark 1200 shown in FIGS. The main control unit 211 that executes this process is an example of a display control unit. Thereby, the direction in which the inclination of the fundus oculi Ef becomes maximum in the peripheral region of the optic disc can be visually recognized.

  When the fundus front image 2122 indicating the surface form of the fundus oculi Ef is stored in the storage unit 212, the main control unit 211 superimposes the fundus front image 2122 on display information (such as the nipple inclination map 1100 and the maximum inclination mark 1200). Can be displayed.

  When the fundus front image 2122 is used, the fundus analyzer may include a fundus front image acquisition unit. The fundus front image acquisition unit irradiates the fundus Ef with light, and acquires the fundus front image 2122 based on detection data of the fundus reflection light. In this embodiment, the fundus front image acquisition unit includes the fundus camera unit 2. The configuration of the fundus front image acquisition unit is not limited to the configuration as a fundus camera, and may be an SLO, an ophthalmic surgical microscope, a slit lamp, or the like.

  The cross-sectional data 2121 to be processed by the fundus analyzing apparatus 1 may be a three-dimensional cross-sectional image showing a cross-sectional form of a three-dimensional region including the optic disc and its surrounding region. In that case, the analysis unit 231 may include a nipple center specifying unit 2311. The nipple center specifying unit 2311 performs processing for analyzing the three-dimensional cross-sectional image and specifying the nipple center C. The analysis unit 231 obtains an index based on the identified nipple center C.

  When the cross-sectional data 2121 is a three-dimensional cross-sectional image, the fundus analysis apparatus may include a three-dimensional cross-sectional image acquisition unit. The three-dimensional cross-sectional image acquisition unit acquires a three-dimensional cross-sectional image by performing OCT measurement on a three-dimensional region including the optic disc and the surrounding region. In this embodiment, the three-dimensional cross-sectional image acquisition unit includes a member that forms a signal optical path in the fundus camera unit 2, an OCT unit 100, an image forming unit 220, and a data processing unit 230 that performs a three-dimensional image forming process. Consists of including. In OCT measurement, a three-dimensional scan is applied.

  When the cross-sectional data 2121 is not a three-dimensional cross-sectional image, the fundus analysis apparatus may include a two-dimensional cross-sectional image acquisition unit. The two-dimensional cross-sectional image acquisition unit acquires a two-dimensional cross-sectional image indicating the cross-sectional form of the circular region R by performing OCT measurement on the circular region R. In this embodiment, the two-dimensional cross-sectional image acquisition unit includes a member that forms a signal optical path in the fundus camera unit 2, an OCT unit 100, and an image forming unit 220. A circle scan is applied in the OCT measurement.

  It is possible to configure the fundus analysis apparatus so as to perform diagnosis support based on the obtained index. In that case, correspondence information 2123 in which the range of the index (tilt information, slope distribution information, etc.) and the degree of the disease are associated is stored in the storage unit 212. The analysis unit 231 specifies the degree of the disease based on the acquired index and the correspondence information 2313.

[Modification]
The configuration described above is merely an example for favorably implementing 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 signal light LS and the optical path of the reference light LR is changed by changing the position of the optical path length changing unit 41, but 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 signal light LS. 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.

1 Fundus Analysis Device 2 Fundus Camera Unit 100 OCT Unit 200 Arithmetic Control Unit 210 Control Unit 211 Main Control Unit 212 Storage Unit 2121 Cross Section Data 2122 Fundus Frontal Image 2123 Corresponding Information 220 Image Forming Unit 230 Data Processing Unit 231 Analysis Unit 2311 Identification of Nipple Center Unit 2312 region dividing unit 2313 layer position acquisition unit 2314 average value calculation unit 2315 inclination information acquisition unit 2316 inclination distribution information creation unit 2317 disease determination unit 241 display unit 242 operation unit E eye E fundus D optic nerve head C nipple center R circular region G1, G2 Two-dimensional cross-sectional image Hi Partial region L Retinal pigment epithelium layer Pj Height position Qi Average value ΔQi Displacement amount Di Opposite direction 1000, 2000 Display information 1100 Nipple inclination map 1200 Maximum inclination mark 1300 Color chart 1400 Front of fundus image

Claims (15)

A storage unit that stores cross-sectional data of the peripheral area of the optic disc acquired by optical coherence tomography measurement on the fundus;
A fundus analysis apparatus comprising: an analysis unit that obtains an index for evaluating a fundus morphology based on two or more cross-sectional data located in different directions with respect to the optic disc.   The fundus analysis apparatus according to claim 1, wherein the analysis unit obtains the index based on one or more sets of cross-sectional data corresponding to opposite positions with respect to a nipple center. The surrounding area includes a circular area centered on the nipple center;
The analysis unit
An area dividing unit that equally divides the circular area into a plurality of partial areas;
The fundus analysis apparatus according to claim 2, wherein the index is obtained based on cross-sectional data included in a partial region corresponding to a facing position with respect to a nipple center among the plurality of partial regions. The cross-sectional data includes a cross-sectional image in the surrounding region,
The analysis unit
A position acquisition unit that analyzes the cross-sectional image and acquires a predetermined position of the fundus in the height direction of the cross-sectional image;
For each of the plurality of partial areas, an average value calculating unit that calculates an average value of the predetermined positions in the partial areas;
An inclination information acquisition unit that obtains, as the index, inclination information indicating the inclination of the fundus in the opposite direction based on the average value calculated for the partial region corresponding to the opposite position. The fundus analysis apparatus according to 3.   The inclination information acquisition unit calculates a new average value based on the plurality of average values calculated for the plurality of partial regions, and calculates a displacement amount of each of the plurality of average values with respect to the new average value. The fundus analysis apparatus according to claim 4, wherein the inclination information is obtained based on the displacement amount.   The said analysis part contains the inclination distribution information preparation part which produces the inclination distribution information which shows distribution of the inclination of the fundus in the said circular area based on the said inclination information. Fundus analyzer.   The fundus analysis apparatus according to claim 6, further comprising: a display control unit configured to display, on a display unit, display information obtained by color-coding a fundus tilt distribution in the circular region based on the tilt distribution information.   The fundus analysis apparatus according to claim 6, further comprising: a display control unit configured to display display information indicating a direction in which the fundus tilt is maximized in the circular region based on the tilt distribution information. The storage unit stores a fundus front image showing a surface form of the fundus,
The fundus analysis apparatus according to claim 7 or 8, wherein the display control unit displays the display information so as to overlap the fundus front image.   The fundus analysis apparatus according to claim 9, further comprising a fundus front image acquisition unit that irradiates light to the fundus and acquires the fundus front image based on detection data of the fundus reflection light.   The fundus analysis apparatus according to any one of claims 1 to 10, wherein the cross-sectional data is a three-dimensional cross-sectional image showing a cross-sectional form of a three-dimensional region including an optic disc and a surrounding region thereof. . The cross-sectional data is a three-dimensional cross-sectional image showing a cross-sectional form of a three-dimensional region including the optic nerve head and surrounding regions thereof,
The analysis unit
Including a nipple center specifying part for analyzing the three-dimensional cross-sectional image and specifying a nipple center;
The fundus analyzer according to any one of claims 2 to 10, wherein the index is obtained based on the identified nipple center.   The fundus analysis apparatus according to claim 11, further comprising a three-dimensional cross-sectional image acquisition unit that acquires the three-dimensional cross-sectional image by performing optical coherence tomography measurement on the three-dimensional region.   11. A two-dimensional cross-sectional image acquisition unit that acquires a two-dimensional cross-sectional image indicating a cross-sectional form of the circular region by performing optical coherence tomography measurement on the circular region. The fundus analysis apparatus according to any one of the above. The storage unit stores correspondence information in which the range of the index is associated with the degree of disease,
The fundus analysis apparatus according to any one of claims 1 to 14, wherein the analysis unit includes a disease determination unit that determines a degree of a disease based on the obtained index and the correspondence information. .

Images