JP2019154988A - Ophthalmologic imaging apparatus, control method therefor, program, and storage medium - Google Patents

Abstract

To appropriately set a plurality of fixation positions for acquiring a mosaic image using OCT, regardless of an individual difference in the size of an eyeball or characteristics.SOLUTION: In an ophthalmologic apparatus according to the embodiment, a fixation system presents fixation targets to a subject eye. An image acquisition unit applies OCT to the eyeground of the subject eye to acquire an image. An eyeball parameter acquisition unit acquires an eyeball parameter of the subject eye. A fixation position setting unit sets a plurality of fixation positions on the basis of the eyeball parameter. A control unit controls the fixation system such that a plurality of fixation targets corresponding to the plurality of fixation positions are sequentially presented to the subject eye, and also controls the image acquisition unit such that a three-dimensional image of the eyeground is acquired while the plurality of fixation targets are each presented to the subject eye. An image processing unit forms a combined image of a plurality of three-dimensional images respectively corresponding to the plurality of fixation positions, the plurality of three-dimensional images being acquired by the image acquisition unit under control of the control unit.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an ophthalmologic photographing apparatus, a control method thereof, a program, and a recording medium.

  Image diagnosis occupies an important position in the field of ophthalmology. In recent years, the use of optical coherence tomography (OCT) has progressed. OCT is used not only for acquiring B-scan images and three-dimensional images of the eye to be examined, but also for acquiring front images (en-face images) such as C-scan images and shadowgrams.

  Also, a modality that acquires an image in which a specific part of the eye to be examined is emphasized has been put into practical use. For example, OCT angiography (OCT-Angiography) that forms an image in which retinal blood vessels and choroidal blood vessels are emphasized has attracted attention (see, for example, Patent Document 1). In general, the tissue (structure) of the scan site is not changed in time, but the blood flow portion inside the blood vessel changes in time. In OCT angiography, an image is formed by emphasizing a portion (blood flow signal) where such a temporal change exists. Note that OCT angiography is also called OCT motion contrast imaging. An image acquired by OCT angiography is called an angiographic image, an angiogram, a motion contrast image, or the like.

  In typical conventional OCT angiography, a three-dimensional scan of a predetermined size (for example, 9 mm × 9 mm) is applied, and an image representing a three-dimensional distribution of fundus blood vessels is obtained. On the other hand, it is desired to acquire a wider range of angiographic images. Panoramic imaging is known as a technique for acquiring OCT data in a wide range of the fundus (see, for example, Patent Document 2).

  Panorama shooting is an imaging technique in which a three-dimensional scan is applied to each of a plurality of different regions, and a plurality of three-dimensional images obtained thereby are combined to construct a wide area image. Overlapping areas are set in areas adjacent to each other, and relative positions between adjacent images are determined based on the overlapping areas. In addition, sequential three-dimensional scanning for a plurality of different regions is typically realized by moving the fixation position. A wide-area image acquired by panoramic shooting is called a panoramic image, a mosaic image, or the like.

  By the way, there are individual differences in the size and characteristics of the eyeball, and for example, the axial length and diopter (eye refractive power) are different for each individual. As described above, even when a three-dimensional scan of a predetermined size is applied, the fundus range actually scanned varies depending on the axial length and diopter.

  For example, as shown in FIG. 1, when the OCT measurement light is incident on the eye E1 having the axial length L1 and the eye E2 having the axial length L2 (> L1) at the same angle θ, the fundus of the eye E1 to be examined The height Y2 of the measurement light projection position on the fundus of the subject eye E2 is larger than the height Y1 of the measurement light projection position at (Y2> Y1). That is, the longer the axial length, the greater the height of the measurement light projection position on the fundus. On the other hand, the size of the OCT scan is defined by the maximum deflection angle of the measurement light. Therefore, even if the size conditions of the OCT scan are the same, the fundus range that is actually scanned changes according to the value of the axial length. The same applies to the diopter.

  As described above, since the actual scan range is affected by the eyeball parameter, the size of the overlapping region in panoramic imaging also changes according to the eyeball parameter. For example, when the eye axis length of the eye to be examined is long, the actual scanning range is widened, so that the overlapping area is also widened. If the overlapping area becomes larger than necessary, the range actually drawn by the mosaic image becomes narrow, and the efficiency of panoramic photography decreases.

  On the contrary, when the eye axis length of the eye to be examined is short, the actual scanning range is narrowed, so the overlapping area is also narrowed, and in some cases, the overlapping area is eliminated. If the overlapping region becomes narrow, there is a possibility that the relative position between adjacent images cannot be obtained with sufficient accuracy. In addition, when there is no overlapping area, the relative position between adjacent images cannot be determined, and a mosaic image cannot be constructed.

  In addition, there may be a situation in which a region of interest (for example, the macula center) that is desired to be drawn in the central region of the mosaic image is not arranged as such.

Special table 2015-515894 gazette JP 2009-183332 A

  An object of the present invention is to provide a technique capable of suitably setting a plurality of fixation positions for acquiring a mosaic image using OCT regardless of individual differences in eyeball size and characteristics. It is in.

  A first aspect of the embodiment includes a fixation system that presents a fixation target to the eye to be examined, an image acquisition unit that acquires an image by applying optical coherence tomography (OCT) to the fundus of the eye to be examined, An eyeball parameter acquisition unit that acquires eyeball parameters of the eye to be examined, a fixation position setting unit that sets a plurality of fixation positions based on the eyeball parameters, and a plurality of fixation targets corresponding to the plurality of fixation positions The fixation system is controlled so as to be sequentially presented to the eye to be examined, and a three-dimensional image of the fundus is acquired when each of the plurality of fixation targets is presented to the eye to be examined. A control unit that controls the image acquisition unit, and an image processing unit that forms a composite image of a plurality of three-dimensional images corresponding to the plurality of fixation positions acquired by the image acquisition unit under the control of the control unit An eye characterized by containing It is an imaging apparatus.

  A second aspect of the embodiment is the ophthalmologic photographing apparatus according to the first aspect, wherein the fixation position setting unit changes the arrangement of a plurality of predetermined fixation positions based on the eyeball parameters. Set the fixation position.

  A third aspect of the embodiment is the ophthalmologic photographing apparatus according to the second aspect, wherein the eyeball parameter includes at least an axial length, and the fixation position setting unit sets at least the axial length of the eye to be examined. The plurality of fixation positions are set by changing the arrangement intervals of the plurality of fixed fixation positions based on the above.

  A fourth aspect of the embodiment is the ophthalmologic imaging apparatus according to the third aspect, wherein the eyeball parameter acquisition unit is based on a predetermined condition for applying OCT to the fundus, and the axial length of the eye to be examined An eye axis length calculation unit that calculates an estimated value of the first eye, and the fixation position setting unit includes a first magnification calculation unit that calculates a first correction magnification based on at least the estimated value of the eye axis length, and the first A first interval correction unit that enlarges or reduces the arrangement interval of the plurality of fixed fixation positions based on the correction magnification.

  A fifth aspect of the embodiment is the ophthalmologic photographing apparatus according to the fourth aspect, wherein the image acquisition unit divides light from a light source into measurement light and reference light, and projects the measurement light onto the fundus An interference optical system that generates interference light by superimposing the return light of the measurement light and the reference light, and detects the interference light, and an image forming unit that forms an image based on the detection result of the interference light And an optical path length changing unit for changing the optical path length of at least one of the measurement light and the reference light, and further includes an alignment unit for aligning the interference optical system with respect to the eye to be examined. The axial length calculation unit calculates an estimated value of the axial length based on at least the alignment result, the optical path length of the measurement light, and the optical path length of the reference light.

  A sixth aspect of the embodiment is the ophthalmologic photographing apparatus according to the fifth aspect, wherein the alignment unit performs the alignment based on a Purkinje image formed by projecting a light beam onto the eye to be examined, and the eye The axial length calculation unit includes a distance between the Purkinje image and the interference optical system, an optical path length of the measurement light, an optical path length of the reference light, a preset standard value of a corneal curvature radius, Based on the measured value of the corneal curvature radius obtained by measuring the eye to be examined, the estimated value of the axial length is calculated.

  A seventh aspect of the embodiment is the ophthalmologic photographing apparatus according to the fifth aspect, wherein the alignment unit is based on two or more anterior eye images acquired by photographing the eye to be examined from different directions. The alignment is performed, and the axial length calculation unit is set in advance with a distance between the pupil of the eye to be examined and the interference optical system, an optical path length of the measurement light, and an optical path length of the reference light The standard value of the corneal thickness or the measured value of the corneal thickness obtained by measuring the eye to be examined in advance and the standard value of the preset anterior chamber depth or the depth of the anterior chamber obtained by measuring the eye to be examined in advance. Based on the measured value, the estimated value of the axial length is calculated.

  An eighth aspect of the embodiment is the ophthalmologic photographing apparatus according to the third aspect, wherein the eyeball parameter acquisition unit includes an axial length measurement unit that measures an axial length of the eye to be examined, and the fixation position The setting unit includes a second magnification calculation unit that calculates a second correction magnification based on at least the measurement value acquired by the axial length measurement unit, and the plurality of predetermined fixation positions based on the second correction magnification. A second interval correction unit that enlarges or reduces the arrangement interval.

  A ninth aspect of the embodiment is the ophthalmologic photographing apparatus according to the third aspect, wherein the eyeball parameter acquisition unit accesses a storage device in which a measurement value of the axial length of the eye to be examined that is acquired in advance is stored. A third magnification calculator that calculates a third correction magnification based on at least the measurement value acquired via the communication unit, and a third correction calculator. A third interval correction unit that enlarges or reduces the arrangement interval of the plurality of predetermined fixation positions based on the magnification.

  A tenth aspect of the embodiment is the ophthalmologic photographing apparatus according to the second aspect, wherein the eyeball parameter includes at least a diopter, and the fixation position setting unit is based on at least the diopter of the eye to be examined. The plurality of fixation positions are set by changing an arrangement interval of the plurality of fixed fixation positions.

  An eleventh aspect of the embodiment is the ophthalmologic photographing apparatus according to the tenth aspect, in which the eyeball parameter acquisition unit calculates the diopter of the eye to be examined based on a predetermined condition for applying OCT to the fundus. A diopter calculating unit that calculates an estimated value, and the fixation position setting unit includes a fourth magnification calculating unit that calculates a fourth correction magnification based on at least the estimated value of the diopter, and a fourth correction magnification. And a fourth interval correction unit that enlarges or reduces the interval between the plurality of predetermined fixation positions based on the fourth interval correction unit.

  A twelfth aspect of the embodiment is the ophthalmologic photographing apparatus according to the eleventh aspect, wherein the image acquisition unit divides light from a light source into measurement light and reference light, and projects the measurement light onto the fundus An interference optical system that generates interference light by superimposing the return light of the measurement light and the reference light, and detects the interference light, and an image forming unit that forms an image based on the detection result of the interference light And further includes a focus adjustment unit for performing focus adjustment of the interference optical system, and the diopter calculation unit calculates an estimated value of the diopter based on a focus state of the interference optical system.

  A thirteenth aspect of the embodiment is the ophthalmologic photographing apparatus according to the twelfth aspect, wherein the focus adjustment unit includes the focusing lens disposed in the optical path of the measurement light, and the optical path of the measurement light. A diopter calculating unit that calculates an estimated value of the diopter based on at least a position of the focusing lens in an optical path of the measurement light.

  A fourteenth aspect of the embodiment is the ophthalmologic photographing apparatus according to the twelfth aspect, wherein the focus adjustment unit detects an index image formed by projecting a light beam on the fundus, and the diopter calculation unit is Then, an estimated value of the diopter is calculated based on the index image.

  A fifteenth aspect of the embodiment is the ophthalmologic imaging apparatus according to any one of the first to fourteenth aspects, wherein the control unit obtains a three-dimensional angiographic image by applying OCT angiography to the fundus. The image acquisition unit is controlled as described above.

  A sixteenth aspect of the embodiment is a method for controlling an ophthalmologic imaging apparatus capable of applying optical coherence tomography (OCT) to the fundus of the subject's eye, wherein the eyeball parameter acquires the eyeball parameter of the subject's eye. An acquisition step; a fixation position setting step for setting a plurality of fixation positions based on the eyeball parameters; and a plurality of fixation targets corresponding to the plurality of fixation positions are sequentially presented to the eye to be examined; and A control step of executing OCT so as to acquire a three-dimensional image of the fundus when each of the plurality of fixation targets is presented to the eye to be examined; and the plurality of fixation targets acquired by the control step Forming a composite image of a plurality of three-dimensional images corresponding to the viewing position.

  A seventeenth aspect of the embodiment is a program that causes an ophthalmic imaging apparatus capable of applying optical coherence tomography (OCT) to the fundus of the subject's eye to execute the control method of the sixteenth aspect.

  An eighteenth aspect of the embodiment is a computer-readable non-transitory recording medium recording the program of the seventeenth aspect.

  According to the embodiment, a plurality of fixation positions for acquiring a mosaic image using OCT can be suitably set regardless of individual differences in eyeball size and characteristics.

It is the schematic for demonstrating background art. It is the schematic showing an example of the structure of the ophthalmologic imaging device which concerns on exemplary embodiment. It is the schematic showing an example of the structure of the ophthalmologic imaging device which concerns on exemplary embodiment. It is the schematic showing an example of the structure of the ophthalmologic imaging device which concerns on exemplary embodiment. It is the schematic showing an example of the structure of the ophthalmologic imaging device which concerns on exemplary embodiment. It is the schematic showing an example of the structure of the ophthalmologic imaging device which concerns on exemplary embodiment. It is the schematic showing an example of the structure of the ophthalmologic imaging device which concerns on exemplary embodiment. It is the schematic showing an example of the structure of the ophthalmologic imaging device which concerns on exemplary embodiment. It is the schematic showing an example of the structure of the ophthalmologic imaging device which concerns on exemplary embodiment. It is the schematic for demonstrating an example of operation | movement of the ophthalmologic imaging device which concerns on exemplary embodiment. It is the schematic for demonstrating an example of operation | movement of the ophthalmologic imaging device which concerns on exemplary embodiment. It is a flowchart showing an example of operation | movement of the ophthalmologic imaging device which concerns on exemplary embodiment. It is the schematic for demonstrating an example of operation | movement of the ophthalmologic imaging device which concerns on exemplary embodiment. It is the schematic for demonstrating an example of operation | movement of the ophthalmologic imaging device which concerns on exemplary embodiment. It is the schematic for demonstrating an example of operation | movement of the ophthalmologic imaging device which concerns on exemplary embodiment.

  An ophthalmologic imaging apparatus, a control method thereof, a program, and a recording medium according to an exemplary embodiment will be described in detail with reference to the drawings. The ophthalmologic photographing apparatus according to the embodiment is an ophthalmologic apparatus having a function of applying optical coherence tomography (OCT) to the fundus. The ophthalmologic imaging apparatus according to the embodiment may be capable of performing OCT angiography of the fundus.

  Hereinafter, an ophthalmologic photographing apparatus in which a swept source OCT and a fundus camera are combined will be described, but the embodiment is not limited thereto. The type of OCT is not limited to swept source OCT, and may be, for example, spectral domain OCT.

  The swept source OCT divides light from a wavelength tunable light source (wavelength swept light source) into measurement light and reference light, and superimposes return light of the measurement light from the test object on the reference light to generate interference light. In this technique, the interference light is detected by a photodetector (for example, a balanced photodiode), and an image is formed by performing Fourier transform or the like on the detection data collected according to the wavelength sweep and the measurement light scan.

  Spectral domain OCT divides light from a low-coherence light source (broadband light source) into measurement light and reference light, and superimposes return light of the measurement light from the test object on the reference light to generate interference light. In this method, the spectral distribution of the interference light is detected by a spectroscope, and the detected spectral distribution is subjected to Fourier transform or the like to form an image.

  That is, the swept source OCT is an OCT technique for acquiring a spectral distribution by time division, and the spectral domain OCT is an OCT technique for acquiring a spectral distribution by spatial division. Note that the OCT technique that can be used in the embodiment is not limited thereto, and an embodiment using any OCT technique (for example, time domain OCT) different from these may be employed.

  The ophthalmologic photographing apparatus according to the embodiment may or may not have a function of acquiring a photograph (digital photograph) of the eye to be examined. Typical examples of ophthalmic modalities having a function of acquiring digital photographs include a fundus camera, a scanning laser ophthalmoscope (SLO), a slit lamp microscope, an anterior ocular photographing camera, and a surgical microscope. Front images such as fundus photographs can be used for fundus observation, scan area setting, tracking, and the like. The ophthalmic modalities that can be used in the embodiment are not limited to these. Also, modalities other than ophthalmology can be used in the embodiment.

  In the present specification, unless otherwise specified, “image data” and “image” based thereon are not distinguished. Similarly, unless otherwise specified, the region or tissue of the eye to be examined is not distinguished from the image representing it.

<Constitution>
The exemplary ophthalmologic imaging apparatus 1 illustrated in FIG. 2 includes a fundus camera unit 2, an OCT unit 100, and an arithmetic control unit 200. The retinal camera unit 2 is provided with an optical system and mechanism for acquiring a front image of the eye E and an optical system and mechanism for performing OCT. The OCT unit 100 is provided with an optical system and a mechanism for performing OCT. The arithmetic control unit 200 includes one or more processors configured to execute various processes (calculation, control, etc.). In addition to these, arbitrary members such as a member for supporting the subject's face (chin rest, forehead rest, etc.), and a lens unit for switching the site to which OCT is applied (for example, anterior segment OCT attachment) These elements and units may be provided in the ophthalmologic photographing apparatus 1.

  In this specification, the “processor” is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), or a programmable logic device (eg, SPLD (Simple ProLigL). It means a circuit such as Programmable Logic Device (FPGA) or Field Programmable Gate Array (FPGA). For example, the processor implements the functions according to the embodiment by reading and executing a program stored in a storage circuit or a storage device.

<Fundus camera unit 2>
The fundus camera unit 2 is provided with an optical system for photographing the fundus oculi Ef of the eye E to be examined. The acquired digital image of the fundus oculi Ef (referred to as a fundus image, fundus photograph, etc.) is generally a front image such as an observation image or a captured image. The observation image is obtained by moving image shooting using near infrared light. The captured image is a still image using flash light in the visible region.

  The fundus camera unit 2 includes an illumination optical system 10 and a photographing optical system 30. The illumination optical system 10 irradiates the eye E with illumination light. The photographing optical system 30 detects the return light of the illumination light irradiated on the eye E. Measurement light from the OCT unit 100 is guided to the eye E through an optical path in the fundus camera unit 2. The return light of the measurement light projected on the eye E (for example, the fundus oculi Ef) is guided to the OCT unit 100 through the same optical path in the fundus camera unit 2.

  The light (observation illumination light) output from the observation light source 11 of the illumination optical system 10 is reflected by the concave mirror 12, passes through the condensing lens 13, passes through the visible cut filter 14, and becomes near infrared light. Further, the observation illumination light is once converged in the vicinity of the photographing light source 15, reflected by the mirror 16, and passed through the relay lens system 17, the relay lens 18, the stop 19, and the relay lens system 20 to the aperture mirror 21. Led. The observation illumination light is reflected by the peripheral part of the perforated mirror 21 (region around the hole part), passes through the dichroic mirror 46, and is refracted by the objective lens 22 to illuminate the eye E (fundus Ef). To do. The return light of the observation illumination light from the eye E 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, and passes through the dichroic mirror 55. The light is reflected by the mirror 32 via the photographing focusing lens 31. Further, the return light passes through the half mirror 33A, is reflected by the dichroic mirror 33, and forms an image on the light receiving surface of the image sensor 35 by the imaging lens 34. The image sensor 35 detects return light at a predetermined frame rate. Note that the focus of the photographing optical system 30 is adjusted to match the fundus oculi Ef or the anterior eye segment.

  The light (imaging illumination light) output from the imaging light source 15 is applied to the fundus oculi Ef through the same path as the observation illumination light. The return light of the imaging illumination light from the eye E is guided to the dichroic mirror 33 through the same path as the return light of the observation illumination light, passes through the dichroic mirror 33, is reflected by the mirror 36, and is reflected by the imaging lens 37. An image is formed on the light receiving surface of the image sensor 38.

  A liquid crystal display (LCD) 39 displays a fixation target (fixation target image). A part of the light beam output from the LCD 39 is reflected by the half mirror 33 </ b> A, reflected by the mirror 32, passes through the hole of the perforated mirror 21 through the photographing focusing lens 31 and the dichroic mirror 55. The light beam that has passed through the aperture of the aperture mirror 21 passes through the dichroic mirror 46, is refracted by the objective lens 22, and is projected onto the fundus oculi Ef. The fixation target is typically used for guidance and fixation of the line of sight. The direction in which the line of sight of the eye E is guided (and fixed), that is, the direction in which fixation of the eye E is promoted is called a fixation position.

  By changing the display position of the fixation target image on the screen of the LCD 39, the fixation position of the eye E by the fixation target can be changed. Examples of fixation positions include a fixation position for acquiring an image centered on the macula (macular imaging fixation position) and a fixation position for acquiring an image centered on the optic nerve head (for papillary imaging). (Fixation position), fixation position for acquiring an image centered on the position between the macula and the optic nerve head (center of the fundus), and an image of a site far from the macula (the fundus periphery) There is a fixation position for.

  A graphical user interface (GUI) or the like for designating at least one of such typical fixation positions can be provided. Further, a GUI or the like for manually moving the fixation position (display position of the fixation target) can be provided. It is also possible to apply a configuration in which the fixation position is automatically set.

  The configuration for presenting a fixation target capable of changing the fixation position to the eye E is not limited to a display device such as an LCD. For example, a device (fixation matrix) in which a plurality of light emitting units (light emitting diodes or the like) are arranged in a matrix can be used instead of the display device. In this case, the fixation position of the eye E by the fixation target can be changed by selectively turning on the plurality of light emitting units. As another example, a fixation target capable of changing the fixation position can be generated by a device including one or more movable light emitting units.

  The alignment optical system 50 generates an alignment index used for alignment of the optical system with respect to the eye E. The alignment light output from the light emitting diode (LED) 51 passes through the diaphragm 52, the diaphragm 53, and the relay lens 54, is reflected by the dichroic mirror 55, passes through the hole of the perforated mirror 21, and passes through the dichroic mirror 46. The light passes through and is projected onto the eye E through the objective lens 22. Return light (corneal reflection light or the like) of the alignment light from the eye E is guided to the image sensor 35 through the same path as the return light of the observation illumination light. Manual alignment or auto-alignment can be executed based on the received light image (alignment index image).

  The focus optical system 60 generates a split index used for focus adjustment with respect to the eye E. The focus optical system 60 is moved along the optical path (illumination optical path) of the illumination optical system 10 in conjunction with the movement of the imaging focusing lens 31 along the optical path (imaging optical path) of the imaging optical system 30. The reflector 67 is inserted into and removed from the illumination optical path. When performing the focus adjustment, the reflecting surface of the reflecting bar 67 is inclinedly arranged in the illumination optical path. The focus light output from the LED 61 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, is reflected by the mirror 65, and is reflected by the condenser lens 66 as a reflecting rod 67. The light is once imaged and reflected on the reflection surface. Further, the focus light passes through the relay lens 20, is reflected by the perforated mirror 21, passes through the dichroic mirror 46, and is projected onto the eye E through the objective lens 22. The return light (fundus reflection light or the like) of the focus light from the eye E is guided to the image sensor 35 through the same path as the return light of the alignment light. Manual focusing and autofocusing can be executed based on the received light image (split index image).

  Diopter correction lenses 70 and 71 can be selectively inserted into the photographing optical path between the perforated mirror 21 and the dichroic mirror 55. The diopter correction lens 70 is a plus lens (convex lens) for correcting the intensity hyperopia. The diopter correction lens 71 is a minus lens (concave lens) for correcting intensity myopia.

  The dichroic mirror 46 combines the fundus imaging optical path and the OCT optical path (measurement arm). The dichroic mirror 46 reflects light in a wavelength band used for OCT and transmits light for fundus photographing. In the measurement arm, a collimator lens unit 40, a retroreflector 41, a dispersion compensation member 42, an OCT focusing lens 43, an optical scanner 44, and a relay lens 45 are provided in this order from the OCT unit 100 side.

  The retro-reflector 41 is movable in the direction of the arrow shown in FIG. 2, thereby changing the length of the measurement arm. The change of the measurement arm length is used, for example, for optical path length correction according to the axial length, adjustment of the interference state, or the like.

  The dispersion compensation member 42 works together with the dispersion compensation member 113 (described later) disposed on the reference arm so as to match the dispersion characteristics of the measurement light LS and the dispersion characteristics of the reference light LR.

  The OCT focusing lens 43 is moved along the measurement arm to adjust the focus of the measurement arm. Note that the movement of the imaging focusing lens 31, the movement of the focus optical system 60, and the movement of the OCT focusing lens 43 can be controlled in a coordinated manner.

  The optical scanner 44 is substantially disposed at a position optically conjugate with the pupil of the eye E. The optical scanner 44 deflects the measurement light LS guided by the measurement arm. The optical scanner 44 is, for example, a galvano scanner capable of two-dimensional scanning. Typically, the optical scanner 44 includes a one-dimensional scanner for deflecting measurement light in the ± x direction and a one-dimensional scanner for deflecting measurement light in the ± y direction. In this case, for example, either one of these one-dimensional scanners is arranged at a position optically conjugate with the pupil, or a position optically conjugate with the pupil is arranged between these one-dimensional scanners.

<OCT unit 100>
The exemplary OCT unit 100 shown in FIG. 3 is provided with an optical system for performing the swept source OCT. This optical system includes an interference optical system. This interference optical system divides the light from the wavelength tunable light source into measurement light and reference light, and superimposes the return light of the measurement light projected on the eye E and the reference light passing through the reference light path to interfere light. And the interference light is detected. Data (detection signal) obtained by detecting the interference light is a signal representing the spectrum of the interference light and is sent to the arithmetic control unit 200.

  The light source unit 101 includes, for example, a near-infrared wavelength tunable laser that changes the wavelength of emitted light at high speed. The light L0 output from the light source unit 101 is guided to the polarization controller 103 by the optical fiber 102 and its polarization state is adjusted. Further, the light L0 is guided to the fiber coupler 105 by the optical fiber 104 and is divided into the measurement light LS and the reference light LR. The optical path of the measurement light LS is called a measurement arm or the like, and the optical path of the reference light LR is called a reference arm or the like.

  The reference light LR generated by the fiber coupler 105 is guided to the collimator 111 by the optical fiber 110 and converted into a parallel light beam, and is guided to the retro-reflector 114 via the optical path length correction member 112 and the dispersion compensation member 113. The optical path length correction member 112 acts to match the optical path length of the reference light LR and the optical path length of the measurement light LS. The dispersion compensation member 113, together with the dispersion compensation member 42 disposed on the measurement arm, acts to match the dispersion characteristics between the reference light LR and the measurement light LS. The retro-reflector 114 is movable along the optical path of the reference light LR incident thereon, thereby changing the length of the reference arm. The change of the reference arm length is used, for example, for optical path length correction corresponding to the axial length, adjustment of the interference state, or the like.

  The reference light LR that has passed through the retroreflector 114 passes through the dispersion compensation member 113 and the optical path length correction member 112, is converted from a parallel light beam to a focused light beam by the collimator 116, and enters the optical fiber 117. The reference light LR incident on the optical fiber 117 is guided to the polarization controller 118 and its polarization state is adjusted. The reference light LR is guided to the attenuator 120 through the optical fiber 119 and the amount of light is adjusted. Led.

  On the other hand, the measurement light LS generated by the fiber coupler 105 is guided to the collimator lens unit 40 through the optical fiber 127 and converted into a parallel light beam, and the retroreflector 41, the dispersion compensation member 42, the OCT focusing lens 43, and the optical scanner 44. , And through the relay lens 45, reflected by the dichroic mirror 46, refracted by the objective lens 22, and projected onto the eye E. The measurement light LS is scattered and reflected at various depth positions of the eye E. The return light of the measurement light LS from the subject eye E travels in the reverse direction in the measurement arm, is guided to the fiber coupler 105, and reaches the fiber coupler 122 via the optical fiber 128.

  The fiber coupler 122 generates interference light by superimposing the measurement light LS incident through the optical fiber 128 and the reference light LR incident through the optical fiber 121. The fiber coupler 122 generates a pair of interference light LC by branching the generated interference light at a predetermined branching ratio (for example, 1: 1). The pair of interference lights LC are guided to the detector 125 through optical fibers 123 and 124, respectively.

  The detector 125 includes, for example, a balanced photodiode. The balanced photodiode includes a pair of photodetectors that respectively detect the pair of interference lights LC, and outputs a difference between the pair of detection signals obtained by these. The detector 125 sends this output (detection signal such as a differential signal) to the data acquisition system (DAQ) 130.

  A clock KC is supplied from the light source unit 101 to the data collection system 130. The clock KC is generated in synchronization with the output timing of each wavelength that is swept within a predetermined wavelength range by the wavelength variable light source in the light source unit 101. For example, the light source unit 101 divides the light L0 of each output wavelength to generate two branched lights, optically delays one of the branched lights, synthesizes the branched lights, and combines the obtained synthesized lights. A clock KC is generated based on the detection signal. The data collection system 130 performs sampling of the detection signal (difference signal) input from the detector 125 based on the clock KC. The data collection system 130 sends the data obtained by this sampling to the arithmetic and control unit 200.

  In this example, both an element for changing the measurement arm length (for example, the retroreflector 41) and an element for changing the reference arm length (for example, the retroreflector 114 or the reference mirror) are provided. However, only one of these elements may be provided. In addition, elements for changing the difference (optical path length difference) between the measurement arm length and the reference arm length are not limited to these, and any element (such as an optical member or a mechanism) can be employed. .

<Calculation control unit 200>
The arithmetic control unit 200 controls each part of the fundus camera unit 2, the display device 3, and the OCT unit 100. The arithmetic control unit 200 executes various arithmetic processes. For example, the arithmetic control unit 200 performs signal processing such as Fourier transform on the spectrum distribution based on the sampling data group obtained by the data acquisition system 130 for each series of wavelength scans (for each A line), thereby obtaining each A A reflection intensity profile at the line is formed. Furthermore, the arithmetic control unit 200 forms image data by imaging the reflection intensity profile of each A line. The arithmetic processing for that is the same as the conventional swept source OCT.

  The arithmetic control unit 200 includes, for example, a processor, a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk drive, a communication interface, and the like. Various computer programs are stored in a storage device such as a hard disk drive. The arithmetic control unit 200 may include an operation device, an input device, a display device, and the like.

<Control system>
Examples of the configuration of the control system (processing system) of the ophthalmologic photographing apparatus 1 are shown in FIGS. The control unit 210, the image forming unit 220, and the data processing unit 230 are provided in the arithmetic control unit 200, for example.

<Control unit 210>
The control unit 210 includes a processor and controls each unit of the ophthalmologic photographing apparatus 1. The control unit 210 includes a main control unit 211 and a storage unit 212.

<Main control unit 211>
The main control unit 211 includes a processor and controls each element of the ophthalmologic photographing apparatus 1 (including elements shown in FIGS. 2 to 7). The main control unit 211 is realized by cooperation of hardware including a circuit and control software.

  The imaging focusing lens 31 arranged in the imaging optical path and the focus optical system 60 arranged in the illumination optical path are moved by an imaging focusing drive unit (not shown) under the control of the main control unit 211. The retro-reflector 41 provided in the measurement arm is moved by the retro-reflector (RR) drive unit 41A under the control of the main control unit 211. The OCT focusing lens 43 arranged on the measurement arm is moved by the OCT focusing driving unit 43A under the control of the main control unit 211. The main control unit 211 can synchronously execute the movement of the imaging focusing lens 31, the movement of the focus optical system 60, and the movement of the OCT focusing lens 43. The retro-reflector 114 arranged on the reference arm is moved by the retro-reflector (RR) driving unit 114A under the control of the main control unit 211. Each of these drive units includes an actuator such as a pulse motor that operates under the control of the main control unit 211. The optical scanner 44 provided in the measurement arm operates under the control of the main control unit 211.

  For example, the moving mechanism 150 moves at least the fundus camera unit 2 in a three-dimensional manner. In a typical example, the moving mechanism 150 includes an x stage that can move in the ± x direction (left and right direction), an x moving mechanism that moves the x stage, and a y stage that can move in the ± y direction (up and down direction). , A y moving mechanism for moving the y stage, a z stage movable in the ± z direction (depth direction), and a z moving mechanism for moving the z stage. Each of these moving mechanisms includes an actuator such as a pulse motor that operates under the control of the main control unit 211.

<Storage unit 212>
The storage unit 212 stores various data. Examples of the data stored in the storage unit 212 include image data of an OCT image, image data of a fundus image, and eye information to be examined. The eye information includes subject information such as patient ID and name, left / right eye identification information, electronic medical record information, and the like.

<Image forming unit 220>
The image forming unit 220 forms image data based on the data collected by the data collection system 130. The image forming unit 220 includes a processor. The image forming unit 220 is realized by cooperation of hardware including a circuit and image forming software.

  The image forming unit 220 forms cross-sectional image data based on the data collected by the data collection system 130. This processing includes signal processing such as noise removal (noise reduction), filter processing, and fast Fourier transform (FFT) as in the case of the conventional swept source OCT.

  The image data formed by the image forming unit 220 is a group of images formed by imaging reflection intensity profiles in a plurality of A lines (scan lines along the z direction) arranged in an area to which an OCT scan is applied. A data set including image data (a group of A-scan image data).

  The image data formed by the image forming unit 220 is, for example, one or more B-scan image data, or stack data formed by embedding a plurality of B-scan image data in a single three-dimensional coordinate system. The image forming unit 220 can also form volume data (voxel data) by performing an interpolation process or the like on the stack data. Stack data and volume data are typical examples of 3D image data represented by a 3D coordinate system.

  When OCT angiography is performed, the main controller 211 repeatedly scans the same region of the fundus oculi Ef a predetermined number of times. The image forming unit 220 can form a motion contrast image based on the data set collected by the data collection system 130 in this repeated scanning. This motion contrast image is an angiographic image formed by emphasizing the temporal change of the interference signal caused by the blood flow of the fundus oculi Ef. Typically, OCT angiography is applied to a three-dimensional region of the fundus oculi Ef, and an image representing a three-dimensional distribution of blood vessels in the fundus oculi Ef is obtained.

  The image forming unit 220 can process the three-dimensional image data. For example, the image forming unit 220 can construct new image data by applying rendering to the three-dimensional image data. Rendering techniques include volume rendering, maximum value projection (MIP), minimum value projection (MinIP), surface rendering, multi-section reconstruction (MPR), and the like. Further, the image forming unit 220 can construct projection data by projecting three-dimensional image data in the z direction (A-line direction, depth direction). Further, the image forming unit 220 can construct a shadowgram by projecting a part of the three-dimensional image data in the z direction. Note that a part of the three-dimensional image data projected to construct the shadowgram is set using, for example, a segmentation described later.

  When OCT angiography is performed, the image forming unit 220 can construct arbitrary two-dimensional angiographic image data and / or arbitrary pseudo three-dimensional angiographic image data from the three-dimensional angiographic image data. It is. For example, the image forming unit 220 can construct two-dimensional angiographic image data representing an arbitrary cross section of the fundus oculi Ef by applying multi-section reconstruction to the three-dimensional angiographic image data.

<Data processing unit 230>
The data processing unit 230 executes various data processing. For example, the data processing unit 230 can apply image processing and analysis processing to OCT image data, and can apply image processing and analysis processing to observation image data or captured image data. The data processing unit 230 includes, for example, at least one of a processor and a dedicated circuit board.

  An exemplary configuration of a processing system including the data processing unit 230 is shown in FIG. The data processing unit 230 of this example includes a fixation position setting unit 231 and an image processing unit 232.

  The fixation system 250 is configured to present a fixation target to the eye E. The fixation system 250 of this example includes the LCD 39 and an optical system for projecting the light flux output from the LCD 39 onto the fundus oculi Ef.

  The image acquisition unit 260 is configured to acquire an image by applying OCT to the fundus oculi Ef of the eye E to be examined. The image acquisition unit 260 of this example includes an element group constituting a measurement arm provided in the fundus camera unit 2, an element group provided in the OCT unit 100, and an image forming unit 220.

  The eyeball parameter acquisition unit 270 acquires the eyeball parameters of the eye E to be examined. The eyeball parameter is a physical quantity representing the characteristics of the eyeball, and examples thereof include an axial length and diopter. The value acquired by the eyeball parameter acquisition unit 270 is, for example, a value (measurement value) obtained by actually measuring the eyeball parameter of the eye E, a value estimated from the measurement or imaging conditions of the eye E ( (Estimated value) or a value obtained from a model eye (standard value). Further, the value acquired by the eyeball parameter acquisition unit 270 may be a value calculated from at least one of a measured value, an estimated value, and a standard value. An example of the eyeball parameter acquisition unit 270 will be described later.

  The fixation position setting unit 231 sets a fixation position for applying OCT to the fundus oculi Ef based on the eyeball parameters acquired by the eyeball parameter acquisition unit 270. In particular, the fixation position setting unit 231 can set a plurality of fixation positions for applying panoramic shooting to the fundus oculi Ef. A configuration example and a processing example of the fixation position setting unit 231 will be described later.

  The image processing unit 232 processes the OCT image acquired by the image acquisition unit 260. Even if the image processing unit 232 can process a fundus image (an observation image, a captured image, etc.) acquired by the fundus camera unit 2 or can process an image acquired by another ophthalmic imaging apparatus. Good.

  For example, the image processing unit 232 can apply segmentation to 2D cross-sectional image data or 3D image data. Segmentation is a process for specifying a partial region in an image. Typically, the segmentation is used to specify an image region corresponding to a predetermined tissue of the fundus oculi Ef.

  As described above, the image forming unit 220 can construct a shadowgram (front angiographic image data or the like) by projecting the image region specified by the segmentation in the z direction. Examples of shadowgrams include shadowgrams corresponding to any depth region of the fundus oculi Ef (eg, shallow retina, deep retina, choroidal capillary plate, sclera, etc.), and any tissue (eg, inner boundary membrane, Nerve fiber layer, ganglion cell layer, inner plexiform layer, inner granule layer, outer reticular layer, outer granule layer, outer boundary membrane, retinal pigment epithelium, Bruch's membrane, choroid, choroidal sclera boundary, sclera, one of these Or a combination of at least two of them).

  The image processing unit 232 includes an image processing processor and an image analysis processor. The image processor is realized in cooperation with hardware including a circuit and image processing software. The image analysis processor is realized by cooperation of hardware including a circuit and image analysis software.

  The image processing unit 232 includes a composition processing unit 2321. The composition processing unit 2321 forms a composite image of two or more three-dimensional images acquired corresponding to two or more different fixation positions in panoramic photography. Processing that can be executed by the composition processing unit 2321 of this example will be described later.

  The fixation position setting unit 231 of the present embodiment may be configured to set a plurality of fixation positions of the panoramic camera by changing the arrangement of a plurality of predetermined fixation positions based on eyeball parameters.

  The plurality of fixed fixation positions are, for example, fixation position groups set in advance for panoramic photographing of the fundus of the eye with standard eyeball parameters. Typically, the plurality of predetermined fixation positions are a group of fixation positions that can be used for panoramic imaging of the fundus of an eye having a standard determined axial length. In addition, a plurality of predetermined fixation positions are a fixation position group that is statistically determined from a sample of a long eye axis length, a fixation position group that is statistically determined from a sample of a short eye long eye, It may include any of a fixation position group determined based on patient attributes such as age and gender, a fixation position group determined based on a disease, and a fixation position group determined based on a candidate disease .

  The plurality of predetermined fixation positions are defined by, for example, feature points of the fundus. Typically, each of a plurality of predetermined fixation positions is defined by a relative position (relative coordinates) based on a fixation position (macular fixation position) corresponding to the macula (macular center, fovea). Is done.

  Hereinafter, several examples of configurations for setting a plurality of fixation positions of a panoramic camera by changing the arrangement of a plurality of predetermined fixation positions based on eyeball parameters will be described.

  For example, the fixation position setting unit 231 changes the arrangement of a plurality of predetermined fixation positions based on eyeball parameters obtained from a predetermined condition for collecting three-dimensional data of the fundus oculi Ef by a three-dimensional OCT scan. The correction magnification for this can be calculated. Typically, the fixation position setting unit 231 calculates at least one of an estimated value of the axial length of the eye E and an estimated value of diopter (refractive power), and a correction magnification based on the calculated estimated value. It may be comprised so that it may ask for. In addition, the value used for calculation of magnification correction is not limited to these, and may be any characteristic value related to the eye E to be examined.

  In the following example, the predetermined condition for the three-dimensional OCT scan may include any of a condition regarding alignment, a condition regarding focus, and a condition regarding OCT optical path length. The condition relating to the alignment and the condition relating to the OCT optical path length are used for, for example, calculation of an estimated value of the axial length. The condition relating to the focus is used, for example, for calculating an estimated value of diopter.

  In another example, the fixation position setting unit 231 sets a correction magnification for changing the arrangement of a plurality of predetermined fixation positions based on a measurement value obtained by actually measuring the eyeball parameter of the eye E. Can be calculated. Alternatively, the fixation position setting unit 231 calculates a correction magnification for changing the arrangement of a plurality of predetermined fixation positions based on, for example, measurement values of eyeball parameters of the eye E acquired in advance by an external device. Can do.

<First Example of Processing System>
FIG. 6A shows a first example of the processing system shown in FIG. Unless otherwise noted, the elements of this example are similar to the corresponding elements shown in FIG. In this example, the eyeball parameter includes the axial length. The fixation position setting unit 231 sets a plurality of fixation positions for panoramic photographing of the fundus oculi Ef by changing the arrangement intervals of the plurality of predetermined fixation positions based on the axial length of the eye E.

  The fixation position setting unit 231 of this example includes a magnification calculation unit 2311A and an interval correction unit 2312A. The eyeball parameter acquisition unit 270 of this example includes an axial length calculation unit 271A.

  The axial length calculation unit 271A calculates an estimated value of the axial length of the eye E based on a predetermined condition for applying OCT to the fundus oculi Ef. In this example, this estimated value is used as an eyeball parameter of the eye E to be examined. The magnification calculator 2311A calculates the correction magnification based on the estimated value of the axial length calculated by the axial length calculator 271A. The interval correction unit 2312A enlarges or reduces the arrangement intervals of the plurality of predetermined fixation positions based on the correction magnification. Thereby, a plurality of fixation positions for panoramic photographing of the fundus oculi Ef are set.

The estimation of the axial length by the axial length calculation unit 271A will be described. As an example, the method disclosed in Japanese Patent Application Laid-Open No. 2008-237237 can be applied. That is, the optical path length of the reference arm is OPL _R , the optical path length of the measurement arm is OPL _S , the working distance is WD, and from the position where the measurement light LS is incident on the eye E to the reflection position of the measurement light LS on the fundus Ef If the intraocular distance of D is D, these parameters have the following relationship: OPL _R = OPL _S + WD + D. Accordingly, the intraocular distance D (that is, the estimated value D of the axial length) is expressed as follows: D = OPL _R −OPL _S −WD.

  When the alignment of the optical system of the ophthalmologic photographing apparatus 1 with respect to the eye E is suitably performed, the optical system (objective lens 22) is disposed at a position away from the eye E by a predetermined working distance WD in the −z direction. The As described above, in this example, the working distance WD is a preset constant, and the optical system and the eye to be examined are provided on the condition that the alignment has been completed (and that the subsequent tracking is preferably performed). It is assumed that the distance to E is equal to the working distance WD, and this constant WD applies. In this example, the working distance WD corresponds to a condition related to alignment.

  In addition, the conditions regarding alignment are not limited to the default value of a working distance. For example, the distance (distance in the z direction) between the eye E and the optical system can be obtained as in the case of performing alignment using two or more cameras that can photograph the eye E from different directions. If a possible configuration is employed, this distance value can be used as a condition for alignment instead of working distance WD.

  In general, before performing the OCT scan of the fundus oculi Ef, the optical path length of the interference optical system is adjusted so that the image of the fundus oculi Ef is displayed at a predetermined position in the frame of the OCT image. Specifically, at least one of the optical path length of the measurement arm and the optical path length of the reference arm is adjusted. The optical path length of the measurement arm can be changed, for example, by the retroreflector 41 and the retroreflector driving unit 41A under the control of the main control unit 211. The optical path length of the reference arm can be changed by the retroreflector 114 and the retroreflector driving unit 114A under the control of the main control unit 211.

  The position of the retro-reflector 41 or the operating state of the actuator of the retro-reflector driving unit 41A is detected using, for example, a position detector (potentiometer, encoder, etc.) not shown. Or based on the control content (control history) of the main control part 211 with respect to 41 A of retroreflector drive parts, it can also comprise so that the position of the retroreflector 41 or the operation state of the actuator of the retroreflector drive part 41A may be detected.

Further, the position of the retro-reflector 41 or the operation state of the actuator of the retro-reflector driving unit 41A can be associated in advance with the value of the optical path length of the measurement arm. This association is performed based on, for example, measurement arm design data. Correspondence information (table information, graph information, etc.) representing this association is created in advance and stored in the storage unit 212, for example. The optic axis length calculation unit 271A receives the detection result of the position of the retroreflector 41 (or the detection result of the operating state of the actuator of the retroreflector drive unit 41A), and obtains the value of the optical path length corresponding to this position from the correspondence information. . The obtained optical path length value is used as the optical path length OPL _S of the measurement arm.

It is possible to obtain the optical path length OPL _R of the reference arm by a similar method. The optical path length OPL _R of the reference arm and the optical path length OPL _S of the measurement arm correspond to conditions relating to the OCT optical path length.

  If only one of the optical path length of the measuring arm and the optical path length of the reference arm can be changed, the optical path length of one arm whose optical path length can be changed is calculated, for example, as described above, and the optical path length A predetermined value (design data) is applied as the optical path length of the other arm to which is fixed.

The optic axis length calculation unit 271A calculates the optical path length OPL _{R of} the reference arm, the optical path length OPL _S of the measurement arm, and the working distance WD obtained as described above, using the above-described arithmetic expression “D = OPL _R −OPL _S − By substituting for “WD”, an estimated value D of the axial length can be calculated.

  The magnification calculator 2311A can calculate the correction magnification based on the estimated value of the axial length calculated by the axial length calculator 271A. This correction magnification is determined based on, for example, the difference or ratio of the estimated value with respect to the standard value of the axial length determined statistically. Further, information (table information, graph information, etc.) in which the value of the correction magnification is associated with various values (or various ranges) of the axial length is stored in the storage unit 212 in advance, and the magnification is calculated. The unit 2311A can obtain the correction magnification corresponding to the estimated value of the axial length by referring to this information.

  The interval correction unit 2312A enlarges or reduces the arrangement intervals of the plurality of predetermined fixation positions based on the correction magnification thus obtained. In this example, the correction magnification calculated by the magnification calculator 2311A is used as an enlargement magnification or a reduction magnification of the arrangement intervals of a plurality of predetermined fixation positions. Thereby, a plurality of fixation positions for panoramic photographing of the fundus oculi Ef are set.

  Note that the alignment is typically executed with reference to an alignment index image formed by two bright spot images provided by the alignment optical system 50. However, the alignment method applicable to the ophthalmologic photographing apparatus is not limited to this. In an ophthalmologic photographing apparatus to which another alignment method is applied, an estimated value of the axial length can be calculated by a method according to the alignment method.

  For example, there is an alignment method using a virtual image (Purkinje image) of a corneal reflection image formed by projecting a light beam onto an eye to be examined (see, for example, Japanese Patent Application Laid-Open No. 2009-028287). In an ophthalmologic photographing apparatus to which this alignment method is applied, an estimated value of the axial length can be calculated based on the position of the Purkinje image, that is, the position of the cornea. For example, the axial length calculation unit 271A calculates the relative position between the Purkinje image after alignment and the optical system, and the optical path length of the interference optical system applied in the three-dimensional OCT scan of the fundus oculi Ef (the optical path length of the measurement arm, An estimated value of the axial length of the eye E can be calculated based on the optical path length of the reference arm) and a preset standard value of the corneal curvature radius.

  When the alignment state is suitable, it is known that the position where the Purkinje image is formed is a position displaced in the intraocular direction from the apex of the cornea by a distance that is half the corneal curvature radius. The working distance is acquired as the distance between the Purkinje image and the optical system (objective lens 22). In this example, the standard value (or half the value) of the corneal curvature radius is stored in the storage unit 212 in advance. The standard value may be, for example, a statistical value obtained clinically or a value in a Gull strand model eye. Alternatively, a measurement value of the corneal curvature radius of the eye E can be applied.

The radius of curvature of the cornea (standard value, etc.) is R, the optical path length of the reference arm is OPL _R , the optical path length of the measurement arm is OPL _S , the working distance is WD, and the position where the measurement light LS is incident on the eye E When the intraocular distance to the reflection position of the measurement light LS on the fundus oculi Ef is D, these parameters have the following relationship: OPL _R = OPL _S + WD + D−R / 2 (see FIG. 8). Accordingly, the intraocular distance D (that is, the estimated value D of the axial length) is expressed as follows: D = OPL _R −OPL _S −WD + R / 2. In addition, the code | symbol P of FIG. 8 shows a Purkinje image.

In addition to the optical path length OPL _{R of} the reference arm, the optical path length OPL _S of the measurement arm, and the working distance WD, respectively, the axial length calculation unit 271A is read from the storage unit 212. By substituting the corneal curvature radius R into the above-described arithmetic expression “D = OPL _R −OPL _S −WD + R / 2”, the estimated value D of the axial length can be calculated.

  As another alignment method, there is an alignment method using two or more anterior ocular segment images acquired by using an anterior ocular segment imaging apparatus that images the eye E from different directions (for example, JP2013-248376A). Issue no.). In an ophthalmologic imaging apparatus to which this alignment method is applied, an estimated value of the axial length can be calculated with reference to the position of a predetermined part of the anterior segment, for example, the position of the pupil. For example, the axial length calculation unit 271A calculates the relative position between the pupil of the eye E to be examined and the optical system after alignment and the optical path length (measurement arm) of the interference optical system when three-dimensional data of the fundus oculi Ef is collected. Based on the optical path length of the reference arm, the optical path length of the reference arm), the preset standard value of the corneal thickness, and the preset standard value of the anterior chamber depth. can do.

  According to this alignment method, for example, in the xy direction, the optical axis of the optical system is coincident with the pupil center (pupil centroid) of the eye E, and in the z direction, the optical axis (objective lens 22) is aligned with the pupil center. ) And the optical system are arranged so as to have a predetermined working distance. In this example, the standard value of the corneal thickness and the standard value of the anterior chamber depth are stored in the storage unit 212 in advance. These standard values may be, for example, statistical values obtained clinically or values in a Gull strand model eye. Instead of such a standard value, a value (measured value) obtained by actually measuring the eye E can be applied.

The corneal thickness (standard value, etc.) is T, the anterior chamber depth (standard value, etc.) is C, the optical path length of the reference arm is OPL _R , the optical path length of the measurement arm is OPL _S , and the working distance is WD. When the intraocular distance from the position where the light LS is incident on the eye E to the reflection position of the measurement light LS on the fundus Ef is D, these parameters have the following relationship: OPL _R = OPL _S + WD + D -TC (see FIG. 9). Accordingly, the intraocular distance D (that is, the estimated value D of the axial length) is expressed as follows: D = OPL _R −OPL _S −WD + T + C. In addition, the code | symbol Q shown in FIG. 9 represents the pupil center (pupil center of gravity).

In addition to the optical path length OPL _{R of} the reference arm, the optical path length OPL _S of the measurement arm, and the working distance WD, respectively, the axial length calculation unit 271A is read from the storage unit 212. By substituting the corneal thickness T and the anterior chamber depth C into the above-described arithmetic expression “D = OPL _R −OPL _S −WD + T + C”, the estimated value D of the axial length can be calculated.

<Second Example of Processing System>
FIG. 6B shows a second example of the processing system shown in FIG. Unless otherwise noted, the elements of this example are similar to the corresponding elements shown in FIG. In this example, the eyeball parameter includes the axial length. The fixation position setting unit 231 sets a plurality of fixation positions for panoramic photographing of the fundus oculi Ef by changing the arrangement intervals of the plurality of predetermined fixation positions based on the axial length of the eye E.

  The fixation position setting unit 231 of this example includes a magnification calculation unit 2311B and an interval correction unit 2312B. The eyeball parameter acquisition unit 270 of this example includes an axial length measurement unit 271B.

  The axial length measuring unit 271B measures the axial length of the eye E. The axial length measuring unit 271B has a known configuration for measuring the axial length by an arbitrary physical method such as an optical method or an acoustic method. As an optical ocular axial length measurement method, for example, a technique disclosed in Japanese Patent Application Laid-Open No. 2017-080136 is known. As an acoustic axial length measurement method, for example, a method disclosed in Japanese Patent Application Laid-Open No. 2010-172538 is known.

  The magnification calculator 2311B can calculate the correction magnification based on the measured value of the axial length of the eye E acquired by the axial length measuring unit 271B. As the correction magnification, for example, information (table information, graph information, etc.) in which the value of the correction magnification is associated with various values (or various ranges) of the axial length is stored in the storage unit 212 in advance. The magnification calculator 2311B can obtain the correction magnification corresponding to the measurement value of the axial length by referring to this information.

  The interval correction unit 2312B enlarges or reduces the arrangement intervals of the plurality of predetermined fixation positions based on the correction magnification thus obtained. In this example, the correction magnification calculated by the magnification calculator 2311B is used as an enlargement magnification or a reduction magnification of the arrangement intervals of a plurality of predetermined fixation positions. Thereby, a plurality of fixation positions for panoramic photographing of the fundus oculi Ef are set.

<Third example of processing system>
FIG. 6C shows a third example of the processing system shown in FIG. Unless otherwise noted, the elements of this example are similar to the corresponding elements shown in FIG. In this example, the eyeball parameter includes the axial length. The fixation position setting unit 231 sets a plurality of fixation positions for panoramic photographing of the fundus oculi Ef by changing the arrangement intervals of the plurality of predetermined fixation positions based on the axial length of the eye E.

  The fixation position setting unit 231 of this example includes a magnification calculation unit 2311C and an interval correction unit 2312C. The eyeball parameter acquisition unit 270 of this example includes a communication unit 271C.

  The communication unit 271C includes a communication device for accessing a storage device in which a measurement value of the axial length of the eye E to be obtained that has been acquired in advance is stored. This storage device is included in, for example, a hospital information system (HIS) having a function of managing electronic medical records. In a typical example, the control unit 210 controls the communication unit 271C to transmit a request for accessing the subject's electronic medical record to the hospital information system, and measure the axial length of the eye E. A value is obtained from the electronic medical record.

  The magnification calculator 2311C can calculate the correction magnification based on the measurement value of the axial length of the eye E acquired through the communication unit 271C. As the correction magnification, for example, information (table information, graph information, etc.) in which the value of the correction magnification is associated with various values (or various ranges) of the axial length is stored in the storage unit 212 in advance. The magnification calculator 2311C can obtain the correction magnification corresponding to the measurement value of the axial length by referring to this information.

  The interval correction unit 2312C enlarges or reduces the arrangement intervals of the plurality of fixed fixation positions based on the correction magnification thus obtained. In this example, the correction magnification calculated by the magnification calculator 2311C is used as an enlargement magnification or a reduction magnification of the arrangement intervals of a plurality of predetermined fixation positions. Thereby, a plurality of fixation positions for panoramic photographing of the fundus oculi Ef are set.

<Fourth example of processing system>
FIG. 7 shows a fourth example of the processing system shown in FIG. Unless otherwise noted, the elements of this example are similar to the corresponding elements shown in FIG. In this example, the eyeball parameter includes diopter. The fixation position setting unit 231 sets a plurality of fixation positions for panoramic photographing of the fundus oculi Ef by changing the arrangement intervals of the plurality of predetermined fixation positions based on the diopter of the eye E.

  The fixation position setting unit 231 of this example includes a magnification calculation unit 2313 and an interval correction unit 2314. The eyeball parameter acquisition unit 270 of this example includes a diopter calculation unit 272.

  The diopter calculating unit 272 calculates an estimated value of the diopter of the eye E based on a predetermined condition for applying OCT to the fundus oculi Ef. In this example, this estimated value is used as an eyeball parameter of the eye E to be examined. The magnification calculator 2313 calculates a correction magnification based on the diopter estimation value calculated by the diopter calculator 272. The interval correction unit 2314 enlarges or reduces the arrangement intervals of the plurality of predetermined fixation positions based on the correction magnification. Thereby, a plurality of fixation positions for panoramic photographing of the fundus oculi Ef are set.

  Diopter estimation by the diopter calculation unit 272 will be described. In general, before performing the OCT scan of the fundus oculi Ef, the OCT focusing lens 43 arranged on the measurement arm is controlled by the main control unit 211 according to the diopter (refractive power) of the eye E to be examined. It is moved by the OCT focusing drive unit 43A. This process is performed based on, for example, the result of autofocusing of the fundus camera unit 2 using the split index (that is, the movement of the photographing focusing lens 31 and the focus optical system 60). For example, the autofocus of this embodiment is performed by coordinated control of the movement of the imaging focusing lens 31, the movement of the focus optical system 60, and the movement of the OCT focusing lens 43, as in the past.

  The position of the OCT focusing lens 43 or the operating state of the OCT focusing driving unit 43A (or the position of the imaging focusing lens 31 or the operating state of the imaging focusing driving unit (not shown)) is, for example, a position detector (not shown). It is detected using (potentiometer, encoder, etc.). Alternatively, based on the control content (control history) of the main control unit 211 with respect to the OCT focus drive unit 43A (or the imaging focus drive unit), the position of the OCT focus lens 43 or the operation state of the OCT focus drive unit 43A. (Or, the position of the photographing focusing lens 31 or the operation state of a photographing focusing driving unit (not shown)) may be detected. The imaging focusing lens 31 and the OCT focusing lens 43 may be configured to operate independently of each other. In this case, for example, the moving amount of the OCT focusing lens 43 can be determined based on the evaluation value (for example, contrast) of the image obtained by the preliminary scan.

  In addition, the position of the OCT focusing lens 43 or the operating state of the actuator of the OCT focusing driving unit 43A (or the position of the imaging focusing lens 31 or the operating state of the actuator of the imaging focusing driving unit), and visual observation The degree value can be associated in advance. This association is performed based on, for example, design data of the optical system (measurement arm or photographing optical system 30). Correspondence information (table information, graph information, etc.) representing this association is created in advance and stored in the storage unit 212, for example. The diopter calculation unit 272 detects the detection result of the position of the OCT focusing lens 43 (or the detection result of the operation state of the actuator of the OCT focusing drive unit 43A, the detection result of the position of the imaging focusing lens 31, or And a diopter value corresponding to this position is obtained from the correspondence information. The obtained diopter value is used as the estimated diopter value of the eye E.

  The magnification calculation unit 2313 can calculate the correction magnification based on the diopter estimation value calculated by the diopter calculation unit 272. This correction magnification is determined based on, for example, a difference or a ratio of an estimated value with respect to a standard value of diopter that is statistically determined (for example, diopter of a normal eye). Further, information (table information, graph information, etc.) in which correction magnification values are associated with various diopter values (or various ranges) is stored in advance in the storage unit 212, and a magnification calculation unit By referring to this information 2313, the correction magnification corresponding to the estimated diopter value can be obtained.

  The interval correction unit 2314 enlarges or reduces the arrangement intervals of the plurality of predetermined fixation positions based on the correction magnification thus obtained. In this example, the correction magnification calculated by the magnification calculation unit 2313 is used as an enlargement magnification or reduction magnification of the arrangement intervals of a plurality of predetermined fixation positions. Thereby, a plurality of fixation positions for panoramic photographing of the fundus oculi Ef are set.

  In the above example, the estimated value of the diopter is obtained based on the position of the OCT focusing lens 43 (or information substantially equivalent thereto), but a technique applicable to the ophthalmologic photographing apparatus is here. It is not limited. For example, it is possible to detect an index image formed by projecting a light beam on the fundus oculi Ef, and calculate an estimated diopter value based on the index image.

  This index image may be the split index image described above. As in the prior art, the split index image is composed of two bright line images, and the relative position of the two bright line images changes according to the change of the focus state with respect to the fundus oculi Ef. When a suitable focus state is realized, the two bright line images are arranged on the same straight line.

  For example, the two bright line images are detected by the photographing optical system 30 together with the observation image of the fundus oculi Ef. The diopter calculation unit 272 analyzes the observation image to extract two bright line images, and obtains the relative positions (relative displacement direction and relative displacement amount) of the two bright line images.

  For example, relationship information indicating the relationship between the relative position of two bright line images and the diopter value is stored in the storage unit 212 in advance. The diopter value recorded in the relationship information is defined as, for example, a diopter shift amount with respect to a predetermined reference diopter (for example, 0 diopter).

  The diopter calculation unit 272 obtains the diopter value corresponding to the relative position of the two bright line images extracted from the observation image from the relation information. This diopter value can be used as an estimated value of the diopter of the eye E to be examined.

  In the example described above, an estimated value of the diopter of the eye E is calculated based on a predetermined condition for applying OCT to the fundus oculi Ef, and a plurality of fixation positions for panoramic imaging are set based on the estimated value. is doing. On the other hand, the diopter of the eye E is measured by the parameter acquisition unit 270 (a diopter measurement unit (not shown)), and a plurality of fixation positions for panoramic imaging are obtained based on the diopter measurement values obtained thereby. Can be set. The diopter measurement unit may have a configuration similar to that of an eye refractive power measurement device (for example, a refractometer), for example. Alternatively, it is possible to set a plurality of fixation positions for panoramic photographing based on the diopter measurement value of the eye E acquired by accessing the storage device by the parameter acquisition unit 270 (communication unit not shown). It is.

<Other examples of treatment systems>
The eyeball parameters that can be acquired by the parameter acquisition unit 270 may include both the axial length and the diopter. The eyeball parameters that can be acquired by the parameter acquisition unit 270 are not limited to these, and may be any eyeball parameters that can be used to calculate the correction magnification.

  The fixation position setting unit 231 can calculate the correction magnification based on one or more arbitrary eyeball parameters. This process can be executed using, for example, the magnification calculation method disclosed in Japanese Patent Application Laid-Open No. 2008-206684 or Japanese Patent Application Laid-Open No. 2006-043155.

  The correction magnification is calculated as a value with respect to a predetermined reference value, for example. This reference value may be a value according to a predetermined dimension (for example, 6 mm × 6 mm) of the three-dimensional scan, for example. In this case, the three-dimensional scan of the fundus oculi Ef is performed with a target in the range of (dimension 6 mm in the x direction) × (dimension 6 mm in the y direction). However, as described above, even when scanning is performed assuming such a target range, the actual scanned range is larger than the target range (6 mm × 6 mm) due to the influence of the eyeball parameters of the eye E to be examined. Or may be small.

  The correction magnification calculated by the fixation position setting unit 231 corresponds to the ratio of the actual scan range to the target range calculated in consideration of the axial length and diopter of the eye E. In other words, the correction magnification is a correction coefficient for adjusting the size of the actual scan range to the size of the target range, and is a correction coefficient for adjusting the size of the target range to the size of the actual scan range.

  In calculating the correction magnification, in addition to the one or more eyeball parameters described above, a corneal curvature radius, an intraocular lens power, and the like may be referred to. The value of such an eyeball parameter may be, for example, a value acquired by the ophthalmologic photographing apparatus 1, a standard value such as a model eye, or other predetermined value. As an example, when OCT is applied to the anterior segment of the eye E by the ophthalmologic imaging apparatus 1, the corneal curvature radius can be obtained from data obtained by the anterior segment OCT. As another example, the value of the corneal curvature radius in the Gull strand model eye can be used. As yet another example, the power of the intraocular lens implanted in the eye E can be obtained from an electronic medical record or the like.

<User interface 240>
The user interface 240 includes a display unit 241 and an operation unit 242. The display unit 241 includes the display device 3. The operation unit 242 includes various operation devices and input devices. The user interface 240 may include a device such as a touch panel in which a display function and an operation function are integrated. Embodiments that do not include at least a portion of the user interface 240 can also be constructed. For example, the display device may be an external device connected to the ophthalmologic photographing apparatus.

<Operation>
An operation of the ophthalmologic photographing apparatus 1 according to the present embodiment will be described. An example of the operation of the ophthalmologic photographing apparatus 1 is shown in FIG. Note that general preparations such as patient information input have already been completed.

(S1: Start fixation)
First, the ophthalmologic imaging apparatus 1 presents a fixation target corresponding to a predetermined fixation position to the eye E and starts fixation. This fixation target is a fixation target for macular photography, for example. The presentation of the fixation target is continued until the presentation end instruction by the ophthalmologic photographing apparatus 1 or the user.

(S2: Adjust OCT conditions)
Next, the conditions for collecting the three-dimensional data of the fundus oculi Ef are adjusted by the three-dimensional OCT scan. This condition adjustment includes alignment adjustment, focus adjustment, optical path length adjustment (interference sensitivity adjustment, z position adjustment), and the like.

(S3: Acquire eyeball parameters)
The eyeball parameter acquisition unit 270 acquires the eyeball parameters of the eye E to be examined.

  For example, the eyeball parameter acquisition unit 270 (ocular length calculation unit 271A) determines the axial length of the eye E based on the OCT condition (for example, the alignment condition and the optical path length condition) adjusted in step S2. An estimated value can be obtained. In addition, the eyeball parameter acquisition unit 270 (ocular length measuring unit 271B) can measure the axial length of the eye E by, for example, an optical technique or an acoustic technique. In addition, the eyeball parameter acquisition unit 270 (communication unit 271C) can acquire the measurement value of the axial length of the eye E by accessing the subject's electronic medical record or the like.

  Further, the eyeball parameter acquisition unit 270 (diopter calculation unit 272) can obtain an estimated value of the diopter of the eye E based on the OCT condition (for example, focus condition) adjusted in step S2. Further, the eyeball parameter acquisition unit 270 (diopter measurement unit) can measure the diopter (refractive power, diopter) of the eye E to be examined by, for example, an optical method. In addition, the eyeball parameter acquisition unit 270 (communication unit) can acquire the measurement value of the diopter of the eye E by accessing the subject's electronic medical record or the like.

(S4: Set multiple fixation positions for panoramic shooting)
The fixation position setting unit 231 sets a plurality of fixation positions for panoramic shooting based on one or more eyeball parameters acquired in step S3. This fixation position setting is executed in the manner described above, for example, according to the type of eyeball parameter acquired in step S3.

(S5: A plurality of three-dimensional images are acquired by executing panorama shooting)
The main control unit 211 performs panoramic photographing of the fundus oculi Ef based on the plurality of fixation positions set in step S4. More specifically, the main control unit 211 controls the fixation system 250 so that a plurality of fixation targets corresponding to the plurality of fixation positions set in step S4 are sequentially presented to the eye E, In addition, the image acquisition unit 260 is controlled to acquire a three-dimensional image of the fundus oculi Ef when each of these fixation targets is presented to the eye E. Thereby, a plurality of three-dimensional images respectively corresponding to the plurality of fixation positions set in step S4 are obtained.

(S6: forming a composite image)
The image processing unit 232 (combination processing unit 2321) forms a composite image (mosaic image) of the plurality of three-dimensional images acquired in step S5.

  The synthesis of a plurality of three-dimensional images includes, for example, matching between overlapping regions using image correlation and the like, positioning of neighboring three-dimensional images using the result of matching, And a synthesis process with a peripheral three-dimensional image.

(S7: Display / save composite image)
The main control unit 211 can cause the display unit 241 to display the composite image formed in step S6. In addition, the main control unit 211 stores the composite image in the storage unit 212, performs control for transmitting the composite image to an external device, and performs control for recording the composite image on a recording medium. Is possible.

  Further, the main control unit 211 can cause the display unit 241 to display part or all of the plurality of three-dimensional images formed in step S5. This is the end of the processing according to this example.

<Supplementary explanation of operation example>
Please refer to FIG. The code | symbol 301 of FIG. 11 shows the fixation target for macular photography. Reference numeral 311 indicates a three-dimensional scan range centered on the macula (macular imaging scan range). In the macular photographing scan range 311, for example, the length in the x direction is set to L (mm) and the length in the y direction is set to L (mm). The three-dimensional scan pattern is, for example, a raster scan. This raster scan includes, for example, a plurality of line scans extending in the x direction, and these line scans are arranged in parallel in the y direction.

  Reference numeral 302 indicates a peripheral photographing fixation target (peripheral fixation target) corresponding to a position away from the macula by a predetermined distance in the lower left direction. Reference numeral 312 denotes a three-dimensional scan range (peripheral imaging scan range) centered on the peripheral fixation position. For example, the peripheral photographing scan range 312 is set to have a length in the x direction of L (mm) and a length in the y direction of L (mm), similarly to the macular photographing scan range 311.

  On the display screen of the LCD 39, the macular target 301 and the peripheral target 302 are separated by D (pixel, dot).

  When the eye E is a standard eye, as shown in FIG. 11, the overlap area between the macular imaging scan range 311 and the peripheral imaging scan range 312 has a length in the x direction of La (mm) and y The length in the direction is La (mm). In such a case, the overlap region between the 3D image obtained by scanning the macular imaging scan range 311 and the 3D image obtained by scanning the peripheral imaging scan range 312 has a length in the x direction. Is La (mm) and the length in the y direction is La (mm).

  Here, the standard eye typically means an eye whose axial length falls within a standard range (for example, an eye that is neither a long-eye long eye nor a short-eye long eye) and / or diopter. Are in the standard range (eg, eyes that are neither myopic nor hyperopic).

  On the other hand, for example, when the axial length of the eye E is shorter than the standard, as shown in FIG. 12, the dimensions of the macular photographing scan range 321 and the peripheral photographing scan range 322 are the case of a standard eye. It becomes small compared. Here, for each of the macular imaging scan range 321 and the peripheral imaging scan range 322, M <L, where the length in the x direction is M (mm) and the length in the y direction is M (mm). . Further, the overlapping area of the macular photographing scan range 321 and the peripheral photographing scan range 322 has a length in the x direction of Ma (mm) and a length in the y direction of Ma (mm). Here, Ma <La. Thus, when the axial length of the eye E is shorter than the standard, the 3D image obtained by scanning the macular imaging scan range 321 and the 3D image obtained by scanning the peripheral imaging scan range 322 The overlapping area with the image has a length in the x direction of Ma (mm) and a length in the y direction of Ma (mm).

  On the contrary, when the axial length of the eye E is longer than the standard, as shown in FIG. 13, the dimensions of the macular photographing scan range 331 and the peripheral photographing scan range 332 are compared with those of the standard eye. Become bigger. Here, for each of the macular imaging scan range 331 and the peripheral imaging scan range 332, N> L where the length in the x direction is N (mm) and the length in the y direction is N (mm). . Further, the overlapping area of the macular photographing scan range 331 and the peripheral photographing scan range 332 has a length in the x direction of Na (mm) and a length in the y direction of Na (mm). Here, Na> La. Thus, when the axial length of the eye E is longer than the standard, the three-dimensional image obtained by scanning the macular photographing scan range 331 and the three-dimensional image obtained by scanning the peripheral photographing scan range 332 The overlapping area with the image has a length in the x direction of Na (mm) and a length in the y direction of Na (mm).

  As described above, the size of the overlap region between the three-dimensional image corresponding to the macular photographing fixation position and the three-dimensional image corresponding to the peripheral fixation position changes according to the value of the axial length of the eye E to be examined. More specifically, the shorter the axial length of the eye E, the smaller the size of the overlapping region, and the longer the axial length of the eye E, the larger the size of the overlapping region. The same applies to eyeball parameters such as diopter. In this example, it is possible to set a plurality of fixation targets for panoramic imaging using the relationship between the eyeball parameters and the scan range.

  In one example, the fixation position setting unit 231 first calculates (estimates) the size of the overlapping area between two or more scan ranges corresponding to two or more different fixation positions. This process is executed with reference to a predetermined relationship between the eyeball parameter and the scan range, for example. In this example, the fixation position setting unit 231 can further set a fixation position for panoramic shooting based on the estimated size of the overlapping area.

  For example, the fixation position setting unit 231 calculates an estimated value of the size of the overlapping area between two scan ranges corresponding to two different fixation positions, and based on the estimated size value, the fixation position for panoramic shooting is calculated. A viewing position may be set. Here, the parameter indicating the dimension of the overlapping region may include at least one of a length in the x direction, a length in the y direction, a diagonal length, an area, a volume, and the like.

  For example, the fixation position setting unit 231 may set the fixation position for panoramic shooting so that the estimated value of the size of the overlapping region is approximately equal to a predetermined value. This predetermined value indicates, for example, the size (range of dimensions) of the overlapping region to be obtained when the eye E to be examined is a standard eye. For example, as shown in FIG. 11, the default values are a length La in the x direction, a length La in the y direction, a diagonal length (√2) × La, an area La × La, and a volume La × La × ζ ( ζ may include at least one of, for example, an imaging range in the z direction).

  Further, the fixation position setting unit 231 corrects a deviation between these fixation positions based on two scan ranges corresponding to two different fixation positions, thereby determining a fixation position for panoramic shooting. It may be set. For example, the deviation of the predetermined peripheral fixation position relative to the macular imaging fixation position can be corrected based on the scan range corresponding to the fixation position with the macular imaging fixation position as a reference. The corrected peripheral fixation position is set as one of the fixation positions for panoramic shooting.

<Action and effect>
The operation and effect of the ophthalmologic photographing apparatus (1) according to this embodiment will be described.

  The ophthalmologic imaging apparatus (1) according to the present embodiment includes a fixation system (250), an image acquisition unit (260), a parameter acquisition unit (270), a fixation position setting unit (231), and a control unit ( A main control unit 211) and an image processing unit (232).

  The fixation system (250) presents a fixation target to the eye to be examined (E). The image acquisition unit (260) acquires an image by applying optical coherence tomography (OCT) to the fundus (Ef) of the eye to be examined (E).

  The parameter acquisition unit (270) acquires the eyeball parameters of the eye to be examined (E). The fixation position setting unit (231) sets a plurality of fixation positions for panoramic shooting based on the eyeball parameters acquired by the parameter acquisition unit (270).

  The control unit (211) causes the fixation system (250) to sequentially present a plurality of fixation targets corresponding to the plurality of fixation positions set by the fixation position setting unit (231) to the eye to be examined (E). ) And the image acquisition unit (260) is controlled so as to acquire a three-dimensional image of the fundus (Ef) when each of these fixation targets is presented to the eye (E).

  The image processing unit (232) forms a composite image (mosaic image) of a plurality of three-dimensional images corresponding to the plurality of fixation positions acquired by the image acquisition unit (260) under the control of the control unit (211). To do.

  According to such an embodiment, panoramic imaging can be performed by setting a plurality of fixation positions according to the eyeball parameters of the eye to be examined. Therefore, eyeball size information such as the axial length and eyeball characteristics such as diopter Regardless of individual differences such as information, it is possible to suitably perform setting of a plurality of fixation positions for acquiring a mosaic image using OCT.

  In the present embodiment, the fixation position setting unit (231) changes a plurality of predetermined fixation positions based on the eyeball parameters acquired by the eyeball parameter acquisition unit (270), thereby changing a plurality of panoramic shooting positions. It may be configured to set a fixation position.

  According to such a configuration, the arrangement of a plurality of fixation positions set in advance for panoramic imaging can be corrected according to the eyeball parameters of the eye to be examined.

  In the present embodiment, the eyeball parameter may include at least the axial length. Further, the fixation position setting unit (231) sets a plurality of fixation positions for panoramic shooting by changing the arrangement interval of the plurality of predetermined fixation positions based on at least the axial length of the eye (E) to be examined. It may be configured to.

  According to such a configuration, it is possible to correct the arrangement of a plurality of fixation positions set in advance for panoramic imaging according to the axial length of the eye to be examined.

  In this embodiment, the eyeball parameter acquisition unit (270) calculates an axial length that calculates an estimated axial length of the eye to be examined (E) based on a predetermined condition for applying OCT to the fundus (Ef). Part (271A) may be included. Furthermore, the fixation position setting unit (231) may include a first magnification calculation unit (2311A) and a first interval correction unit (2312A). The first magnification calculator (2311A) is configured to calculate the first correction magnification based at least on the estimated value of the axial length calculated by the axial length calculator (271A). The first interval correction unit (2312A) sets a plurality of fixation positions for panoramic shooting by enlarging or reducing the arrangement intervals of the plurality of predetermined fixation positions based on the first correction magnification. It is configured.

  According to such a configuration, the axial length of the eye to be inspected can be estimated based on a predetermined condition for applying the OCT, so that the axial length of the eye to be inspected is not obtained in advance. However, it is possible to correct the arrangement of a plurality of fixation positions set in advance for panoramic shooting.

  In this embodiment, the image acquisition unit (260) includes an interference optical system, an image forming unit (220), an optical path length changing unit (a retroreflector 41 and a retroreflector driving unit 41A, a retroreflector 114 and a retroreflector driving unit 114A). ). The interference optical system divides the light (L0) from the light source (light source unit 101) into measurement light (LS) and reference light (LR), projects the measurement light (LS) onto the fundus (Ef), and measures light. (LS) return light and reference light (LR) are overlapped to generate interference light (LC), and the interference light (LC) is detected. The image forming unit (220) is configured to form an image based on the detection result of the interference light (LC). The optical path length changing unit (retroreflector 41 and retroreflector driving unit 41A, retroreflector 114 and retroreflector driving unit 114A) is configured to change the optical path length of at least one of measurement light (LS) and reference light (LR). Has been. Furthermore, the ophthalmologic imaging apparatus (1) of the present embodiment may further include an alignment unit (alignment optical system 50, anterior ocular segment imaging apparatus, etc.) for performing alignment of the interference optical system with respect to the eye to be examined (E). . In addition, the eye axis length calculation unit (271A) determines the eye of the eye to be examined (E) based on at least the alignment result, the optical path length of the measurement light (LS), and the optical path length of the reference light (LR). It may be configured to calculate an estimated value of the axial length.

  According to such a configuration, one specific example for estimating the axial length of the eye to be examined based on a predetermined condition for applying OCT is provided.

  In the present embodiment, the alignment unit may be configured to perform alignment based on a Purkinje image formed by projecting a light beam onto the eye to be examined (E). Furthermore, the axial length calculation unit (271A) calculates the distance between the Purkinje image and the interference optical system (objective lens 22), the optical path length of the measurement light (LS), and the optical path length of the reference light (LR). Based on a preset standard value of the corneal curvature radius or a measurement value of the corneal curvature radius obtained by measuring the eye (E) in advance, an estimated value of the axial length of the eye to be examined (E) is calculated. It may be configured to.

  According to such a configuration, one specific example for estimating the axial length of the eye to be inspected based on the alignment result or the like is provided.

  In the present embodiment, the alignment unit may be configured to perform alignment based on two or more anterior segment images acquired by imaging the eye to be examined (E) from different directions. Further, the axial length calculation unit (271A) is configured such that the distance between the pupil of the eye to be examined (E) and the interference optical system (objective lens 22), the optical path length of the measurement light (LS), and the reference light (LR). Optical path length, a preset standard value of corneal thickness or a measured value of corneal thickness obtained by measuring a subject eye in advance, a preset standard value of anterior chamber depth or a subject eye (E) in advance The estimated value of the axial length of the eye to be examined (E) may be calculated based on the measurement value of the anterior chamber depth obtained by measurement.

  According to such a configuration, one specific example for estimating the axial length of the eye to be inspected based on the alignment result or the like is provided.

  In the present embodiment, the eyeball parameter acquisition unit (270) may include an axial length measurement unit (271B) that measures the axial length of the eye to be examined (E). The fixation position setting unit (231) includes a second magnification calculation unit (2311B) and a second interval correction unit (2312B). The second magnification calculation unit (2311B) is configured to calculate the second correction magnification based at least on the measurement value acquired by the axial length measurement unit (271B). The second interval correction unit (2312B) sets a plurality of fixation positions for panoramic shooting by enlarging or reducing the arrangement intervals of the plurality of predetermined fixation positions based on the second correction magnification. It is configured.

  According to such a configuration, since the axial length of the eye to be examined can be measured, even if the axial length of the eye to be examined is not obtained in advance, it is set in advance for panoramic photography. It is possible to correct the arrangement of a plurality of fixation positions.

  In this embodiment, the eyeball parameter acquisition unit (270) includes a communication unit (271C) for accessing a storage device in which a measurement value of the axial length of the eye to be examined (E) acquired in advance is stored. Good. Furthermore, the fixation position setting unit (231) may include a third magnification calculation unit (2311C) and a third interval correction unit (2312C). The third magnification calculator (2311C) is configured to calculate the third correction magnification based at least on the measured value of the axial length of the eye to be examined (E) acquired via the communication unit (271C). . The third interval correction unit (2312C) sets a plurality of fixation positions for panoramic shooting by enlarging or reducing the arrangement intervals of the plurality of predetermined fixation positions based on the third correction magnification. It is configured.

  According to such a configuration, it is possible to correct the arrangement of a plurality of fixation positions set in advance for panoramic imaging using a measurement value of the axial length of the eye to be examined acquired in the past. is there.

  In the present embodiment, the eyeball parameter may include at least diopter. Furthermore, the fixation position setting unit (231) sets a plurality of fixation positions for panoramic shooting by changing the arrangement interval of the plurality of predetermined fixation positions based on at least the diopter of the eye to be examined (E). It may be configured to.

  According to such a configuration, the arrangement of a plurality of fixation positions set in advance for panoramic imaging can be corrected according to the diopter of the eye to be examined.

  In the present embodiment, the eyeball parameter acquisition unit (270) is a diopter calculation unit that calculates an estimated value of diopter of the eye to be examined (E) based on a predetermined condition for applying OCT to the fundus (Ef). 272). Furthermore, the fixation position setting unit (231) may include a fourth magnification calculation unit (2313) and a fourth interval correction unit (2314). The fourth magnification calculator (2313) is configured to calculate a fourth correction magnification based at least on the estimated value of the diopter of the eye to be examined (E). The fourth interval correction unit (2314) sets a plurality of fixation positions for panoramic shooting by enlarging or reducing the arrangement intervals of the plurality of predetermined fixation positions based on the fourth correction magnification. It is configured.

  According to such a configuration, since the diopter of the eye to be examined can be estimated based on a predetermined condition for applying OCT, even if the diopter of the eye to be examined is not obtained in advance. It is possible to correct the arrangement of a plurality of fixation positions set in advance for panoramic shooting.

  In the present embodiment, the image acquisition unit may include an interference optical system and an image forming unit (220). The interference optical system divides the light (L0) from the light source (light source unit 101) into measurement light (LS) and reference light (LR), projects the measurement light (LS) onto the fundus (Ef), and measures light. (LS) return light and reference light (LR) are overlapped to generate interference light (LC), and the interference light (LC) is detected. The image forming unit (220) is configured to form an image based on the detection result of the interference light (LC). Furthermore, the ophthalmologic photographing apparatus (1) of the present embodiment may further include a focus adjusting unit (OCT focusing lens 43, OCT focusing driving unit 43A) for performing focus adjustment of the interference optical system. In addition, the diopter calculation unit (272) may be configured to calculate an estimated diopter value of the eye to be examined (E) based on the focus state of the interference optical system.

  According to such a configuration, one specific example for estimating the diopter of the eye to be examined based on a predetermined condition for applying OCT is provided.

  In the present embodiment, the focus adjustment unit includes a focusing lens (OCT focusing lens 43) disposed in the optical path of the measurement light (LS) and a focusing lens (OCT focusing) along the optical path of the measurement light (LS). And a driving unit (OCT focusing driving unit 43A) that moves the lens 43). Further, the diopter calculation unit (272) calculates an estimated value of the diopter of the eye to be examined (E) based on at least the position of the focusing lens (OCT focusing lens 43) in the optical path of the measurement light (LS). It may be constituted as follows.

  According to such a configuration, one specific example for estimating the diopter of the eye to be examined based on the result of focus adjustment is provided.

  In the present embodiment, the focus adjustment unit may be configured to detect an index image formed by projecting a light beam onto the fundus (Ef). Furthermore, the diopter calculation unit (272) may be configured to calculate an estimated diopter value of the eye to be examined (E) based on the detected index image.

  According to such a configuration, one specific example for estimating the diopter of the eye to be examined based on the result of focus adjustment is provided.

  In the present embodiment, the control unit (211) may be configured to control the image acquisition unit (260) so as to acquire a three-dimensional angiographic image by applying OCT angiography to the fundus (Ef). .

  According to such a configuration, it is possible to suitably acquire a three-dimensional angiographic image (mosaic image) over a wide range of the fundus.

  A method for controlling an ophthalmologic imaging apparatus according to the present embodiment is a method for controlling an ophthalmologic imaging apparatus that can apply optical coherence tomography (OCT) to the fundus of a subject's eye. A visual position setting step, a control step, and a synthesis step are included.

  The eyeball parameter acquisition step acquires eyeball parameters of the eye to be examined (E). The fixation position setting step sets a plurality of fixation positions for panoramic shooting based on the acquired eyeball parameters. In the control step, a plurality of fixation targets corresponding to a plurality of set fixation positions are sequentially presented to the eye to be examined (E), and each of the plurality of fixation targets is presented to the eye to be examined (E). OCT is executed so as to acquire a three-dimensional image of the fundus oculi (Ef) when it is being performed. The synthesis step forms a composite image of a plurality of three-dimensional images corresponding to the plurality of fixation positions acquired by the control step.

  According to such an embodiment, panoramic imaging can be performed by setting a plurality of fixation positions according to the eyeball parameters of the eye to be examined. Therefore, eyeball size information such as the axial length and eyeball characteristics such as diopter Regardless of individual differences such as information, it is possible to suitably perform setting of a plurality of fixation positions for acquiring a mosaic image using OCT.

  It is possible to create a program that causes the ophthalmologic photographing apparatus according to the present embodiment to execute such a control method. It is also possible to create a computer-readable non-transitory recording medium that records such a program. This non-temporary recording medium may be in any form, and examples thereof include a magnetic disk, an optical disk, a magneto-optical disk, and a semiconductor memory.

  The embodiment described above is merely an example of the present invention. A person who intends to implement the present invention can arbitrarily make modifications (omission, substitution, addition, etc.) within the scope of the present invention.

  When the eye axis length of the eye to be examined is very long, two adjacent scan ranges may not have overlapping regions among the plurality of scan ranges corresponding to the plurality of fixation positions for panoramic imaging. In this case, an additional three-dimensional OCT scan including a gap region between the two scan ranges is performed, and the additional three-dimensional image obtained by the additional scan is used to correspond to the two scan ranges. It is possible to synthesize two three-dimensional images.

DESCRIPTION OF SYMBOLS 1 Ophthalmic imaging device 210 Control part 211 Main control part 220 Image formation part 230 Data processing part 231 Fixation position setting part 2311A, 2311B, 2311C, 2313 Magnification calculation part 2312A, 2312B, 2312C, 2314 Space | interval correction | amendment part 232 Image processing part 2321 Composition processing unit 250 Fixation system 260 Image acquisition unit 270 Eyeball parameter acquisition unit

Claims (18)

A fixation system that presents a fixation target to the eye to be examined; and
An image acquisition unit that acquires an image by applying optical coherence tomography (OCT) to the fundus of the eye;
An eyeball parameter obtaining unit for obtaining eyeball parameters of the eye to be examined;
A fixation position setting unit that sets a plurality of fixation positions based on the eyeball parameters;
The fixation system is controlled so that a plurality of fixation targets corresponding to the plurality of fixation positions are sequentially presented to the eye to be examined, and each of the plurality of fixation targets is presented to the eye to be examined. A control unit for controlling the image acquisition unit so as to acquire a three-dimensional image of the fundus when
An ophthalmic imaging apparatus comprising: an image processing unit that forms a composite image of a plurality of three-dimensional images corresponding to the plurality of fixation positions acquired by the image acquisition unit under the control of the control unit. . The ophthalmologic photographing apparatus according to claim 1, wherein the fixation position setting unit sets the plurality of fixation positions by changing an arrangement of a plurality of predetermined fixation positions based on the eyeball parameters. The eyeball parameter includes at least an axial length,
The fixed position setting unit sets the fixed positions by changing an arrangement interval of the fixed fixed positions based on at least an axial length of the eye to be examined. The ophthalmologic photographing apparatus described in 1. The eyeball parameter acquisition unit includes an axial length calculation unit that calculates an estimated value of the axial length of the eye to be examined based on a predetermined condition for applying OCT to the fundus,
The fixation position setting unit includes:
A first magnification calculator for calculating a first correction magnification based on at least an estimated value of the axial length;
The ophthalmic imaging apparatus according to claim 3, further comprising: a first interval correction unit that expands or reduces an arrangement interval of the plurality of predetermined fixation positions based on the first correction magnification. The image acquisition unit
The light from the light source is divided into measurement light and reference light, the measurement light is projected onto the fundus, the return light of the measurement light and the reference light are superimposed to generate interference light, and the interference light is An interference optical system to detect,
An image forming unit that forms an image based on the detection result of the interference light;
An optical path length changing unit for changing the optical path length of at least one of the measurement light and the reference light, and
An alignment unit for performing alignment of the interference optical system with respect to the eye to be examined;
The ocular axial length calculation unit calculates an estimated value of the ocular axial length based on at least the result of the alignment, the optical path length of the measurement light, and the optical path length of the reference light. The ophthalmologic imaging apparatus according to claim 4. The alignment unit performs the alignment based on a Purkinje image formed by projecting a light beam onto the eye to be examined.
The axial length calculation unit includes a distance between the Purkinje image and the interference optical system, an optical path length of the measurement light, an optical path length of the reference light, and a standard value of a preset corneal curvature radius or The ophthalmic imaging apparatus according to claim 5, wherein the estimated value of the axial length is calculated based on a measured value of the corneal curvature radius obtained by measuring the eye to be examined in advance. The alignment unit performs the alignment based on two or more anterior segment images acquired by photographing the eye to be examined from different directions,
The axial length calculation unit includes a distance between the pupil of the eye to be examined and the interference optical system, an optical path length of the measurement light, an optical path length of the reference light, and a standard value of a preset corneal thickness Or based on a measurement value of corneal thickness obtained by measuring the eye to be examined in advance and a standard value of preset anterior chamber depth or a measurement value of anterior chamber depth obtained by measuring the eye to be examined in advance The ophthalmic imaging apparatus according to claim 5, wherein an estimated value of the axial length is calculated. The eyeball parameter acquisition unit includes an axial length measurement unit that measures the axial length of the eye to be examined,
The fixation position setting unit includes:
A second magnification calculation unit that calculates a second correction magnification based on at least the measurement value acquired by the axial length measurement unit;
The ophthalmic imaging apparatus according to claim 3, further comprising: a second interval correction unit that expands or reduces an arrangement interval of the plurality of predetermined fixation positions based on the second correction magnification. The eyeball parameter acquisition unit includes a communication unit for accessing a storage device in which a measurement value of the axial length of the eye to be examined acquired in advance is stored,
The fixation position setting unit includes:
A third magnification calculator for calculating a third correction magnification based on at least the measurement value acquired via the communication unit;
The ophthalmic imaging apparatus according to claim 3, further comprising: a third interval correction unit that enlarges or reduces an arrangement interval of the plurality of predetermined fixation positions based on the third correction magnification. The eye parameter includes at least diopter;
3. The fixation position setting unit sets the plurality of fixation positions by changing an arrangement interval of the plurality of predetermined fixation positions based on at least a diopter of the eye to be examined. The ophthalmic imaging apparatus described. The eyeball parameter acquisition unit includes a diopter calculation unit that calculates an estimated value of diopter of the eye to be examined based on a predetermined condition for applying OCT to the fundus.
The fixation position setting unit includes:
A fourth magnification calculator for calculating a fourth correction magnification based on at least the diopter estimation value;
The ophthalmic imaging apparatus according to claim 10, further comprising: a fourth interval correction unit that expands or reduces an arrangement interval of the plurality of predetermined fixation positions based on the fourth correction magnification. The image acquisition unit
The light from the light source is divided into measurement light and reference light, the measurement light is projected onto the fundus, the return light of the measurement light and the reference light are superimposed to generate interference light, and the interference light is An interference optical system to detect,
An image forming unit that forms an image based on the detection result of the interference light, and
A focus adjustment unit for adjusting the focus of the interference optical system;
The ophthalmologic photographing apparatus according to claim 11, wherein the diopter calculation unit calculates an estimated value of the diopter based on a focus state of the interference optical system. The focus adjustment unit
A focusing lens disposed in the optical path of the measurement light;
A drive unit that moves the focusing lens along the optical path of the measurement light, and
The ophthalmologic photographing apparatus according to claim 12, wherein the diopter calculating unit calculates the estimated value of the diopter based on at least a position of the focusing lens in an optical path of the measurement light. The focus adjustment unit detects an index image formed by projecting a light beam on the fundus;
The ophthalmologic photographing apparatus according to claim 12, wherein the diopter calculation unit calculates an estimated value of the diopter based on the index image. The ophthalmologic imaging according to claim 1, wherein the control unit controls the image acquisition unit so as to acquire a three-dimensional angiographic image by applying OCT angiography to the fundus. apparatus. A method for controlling an ophthalmologic imaging apparatus capable of applying optical coherence tomography (OCT) to the fundus of a subject's eye,
An eyeball parameter obtaining step for obtaining eyeball parameters of the eye to be examined; and
A fixation position setting step of setting a plurality of fixation positions based on the eyeball parameters;
When a plurality of fixation targets corresponding to the plurality of fixation positions are sequentially presented to the eye to be examined, and each of the plurality of fixation targets is presented to the eye to be examined, the three-dimensional of the fundus A control step for performing OCT to acquire an image;
A composition step of forming a composite image of a plurality of three-dimensional images corresponding to the plurality of fixation positions acquired by the control step.   A program causing an ophthalmologic imaging apparatus capable of applying optical coherence tomography (OCT) to the fundus of the subject's eye to execute the control method according to claim 16. A computer-readable non-transitory recording medium on which the program according to claim 17 is recorded.

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