Ophthalmic apparatus, its control method, program, and recording medium

Abstract

To improve anterior eye part analysis using optical coherence tomography (OCT).SOLUTION: A fixation target presentation part of an ophthalmologic device presents a fixation target to a subject. An OCT part constructs an image by applying an OCT scan to an anterior eye part of an eye to be examined. An inclination information generation part generates inclination information indicating an inclined state of the anterior eye part visualized in the image. A control part controls the fixation target presentation part on the basis of the inclination information. Furthermore, the OCT part constructs an image by applying either a radial scan including a plurality of B scans with mutually different directions or a three-dimensional scan for a three-dimensional region to the anterior eye part. The inclination information generation part analyzes the image, specifies three or more feature points of an angle of the eye to be examined, and generates the inclination information on the basis of the three or more feature points.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an ophthalmic apparatus, a control method thereof, a program, and a recording medium. [Background technology]

[0002] Anterior segment analysis techniques using optical coherence tomography (OCT) are known, one of which is angle analysis performed to diagnose glaucoma (particularly angle-closure glaucoma) (see, for example, Patent Documents 1 to 4).

[0003] In angle analysis, calculations are performed to determine parameters related to the area between the cornea and iris called the angle (anterior chamber angle) based on OCT images of the anterior segment. If the image of the anterior segment depicted in the OCT image is tilted, the angle parameters may not be determined accurately. In particular, if the scan range is wide, the tilt and distortion of the image of the anterior segment become significant, which has a significant impact on the accuracy of the angle parameters.

[0004] For example, in an angle-to-angle (ATA) scan, a B-scan (line scan) is applied to a cross section passing through the corneal apex, the pupil center, or a position near the apex, and two points on the angle of the eye that are distributed in a roughly circular pattern. In other words, in an ATA scan, a B-scan is applied to a cross section passing through a pair of opposing points on the angle of the eye that are distributed in a roughly circular pattern. If the image of the anterior segment in the OCT image obtained by the ATA scan is tilted, the image of the anterior segment will be distorted, making it impossible to accurately determine the angle-to-angle distance or angle of the angle of the eye.

[0005] The influence of the tilt of the anterior segment image is not limited to iridocorneal angle analysis, but is generally felt in anterior segment analysis, which evaluates the shape and form. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-147611 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-226383 [Patent Document 3] Special Publication No. 2014-500096 [Patent Document 4] Japanese Patent Application Laid-Open No. 2015-43814 Summary of the Invention [Problem to be solved by the invention]

[0007] One object of the present invention is to improve OCT anterior segment analysis. [Means for solving the problem]

[0008] An ophthalmic device according to some exemplary embodiments includes a fixation target presentation unit that presents a fixation target to a subject, an optical coherence tomography (OCT) unit that applies an OCT scan to the anterior segment of the subject's eye to construct an image, a tilt information generation unit that generates tilt information indicating the tilt state of the anterior segment depicted in the image, and a control unit that controls the fixation target presentation unit based on the tilt information.

[0009] In the ophthalmologic apparatus according to some exemplary aspects, the control unit may be configured to control the fixation target presentation unit to move the fixation target.

[0010] In some exemplary aspects of the ophthalmologic device, the control unit may be configured to control the fixation target presentation unit by referring to pre-created correspondence information indicating the correspondence between a tilt parameter indicating the tilt state of the anterior segment in the image frame and a movement parameter of the fixation target.

[0011] In some exemplary embodiments of the ophthalmologic device, the tilt information may include a tilt angle relative to a predetermined first reference direction in the image constructed by the OCT unit, the tilt parameter may include a tilt angle relative to a predetermined second reference direction in the image frame, and the movement parameter may include a movement amount.

[0012] In some exemplary embodiments of the ophthalmic device, the tilt angle included in the tilt parameter may include a predetermined unit angle relative to the second reference direction, and the movement amount included in the movement parameter may include a unit movement amount corresponding to the unit angle.

[0013] In the ophthalmologic apparatus according to some exemplary aspects, the correspondence information may include information indicating correspondence between a plurality of different tilt angles and a plurality of different movement amounts with respect to the second reference direction.

[0014] In some exemplary embodiments of the ophthalmic device, the tilt information may further include a tilt direction relative to the first reference direction, the tilt parameters may further include a tilt direction relative to the second reference direction, and the movement parameters may further include a movement direction.

[0015] In some exemplary embodiments of the ophthalmologic device, the control unit may be configured to control the fixation target presentation unit to move the fixation target, control the OCT unit to sequentially construct images by repeatedly applying OCT scans to the anterior segment of the eye, and control the tilt information generation unit to sequentially generate the tilt information from the images sequentially constructed by the OCT unit, in parallel, and to control the fixation target presentation unit to stop the movement of the fixation target in response to the generation of tilt information that satisfies a predetermined condition.

[0016] In the ophthalmologic apparatus according to some exemplary aspects, the tilt information may include a tilt angle relative to a predetermined reference direction in the image, and the condition may be a condition related to the tilt angle.

[0017] In the ophthalmic apparatus according to some exemplary aspects, the condition may be that the tilt angle is smaller than a predetermined threshold value.

[0018] In some exemplary embodiments of the ophthalmologic device, the control unit may be configured to determine the movement direction of the fixation target based on any of the tilt information sequentially generated by the tilt information generating unit from the images sequentially constructed by the OCT unit, and control the fixation target presenting unit.

[0019] An ophthalmologic device according to some exemplary embodiments includes a fixation target presenting unit that presents a fixation target to a subject, an OCT unit that applies an optical coherence tomography (OCT) scan to the anterior segment of the subject's eye to construct an image, a tilt information generating unit that generates tilt information indicating the tilt state of the anterior segment depicted in the image, an operating unit that generates a signal in response to an operation, and a control unit that controls the fixation target presenting unit based on the signal from the operating unit and displays information based on the tilt information on a display means.

[0020] In some exemplary embodiments of the ophthalmologic device, the information based on the tilt information may include at least one of information indicating a tilt angle relative to a predetermined reference direction in the image, information indicating a movement amount of the fixation target corresponding to the tilt angle, information indicating a tilt direction relative to the reference direction in the image, and information indicating a movement direction of the fixation target corresponding to the tilt direction.

[0021] In some exemplary embodiments of the ophthalmologic device, the gradient information generating unit may be configured to analyze the image constructed by the OCT unit to identify one or more feature points, and generate the gradient information based on the one or more feature points.

[0022] In some exemplary embodiments of the ophthalmic device, the one or more feature points may include at least one of the angle, the apex of the anterior surface of the lens, the apex of the cornea, and a point on the anterior surface of the iris.

[0023] In some exemplary embodiments of the ophthalmic device, the OCT unit may be configured to construct the image by applying an OCT scan to an area including at least two points of the angle of the test eye, and the gradient information generation unit may be configured to identify the at least two points as the feature points and generate the gradient information based on the at least two points.

[0024] In some exemplary embodiments of the ophthalmic device, the OCT unit may be configured to construct the image by applying an OCT scan to an area including the apex of the anterior surface of the lens of the test eye, and the tilt information generation unit may be configured to identify the apex of the anterior surface of the lens as the feature point, determine the tilt of the anterior surface of the lens at the apex of the anterior surface of the lens, and generate the tilt information based on the tilt.

[0025] In some exemplary embodiments of the ophthalmologic device, the OCT unit may be configured to construct the image by applying an OCT scan to an area including the corneal apex of the test eye, and the tilt information generation unit may be configured to identify the corneal apex as the feature point, determine the tilt of the anterior corneal surface at the corneal apex, and generate the tilt information based on the tilt.

[0026] In some exemplary embodiments of the ophthalmic device, the OCT unit may be configured to construct the image by applying an OCT scan to an area including at least a portion of the anterior iris surface of the test eye, and the tilt information generation unit may be configured to identify at least two points on the anterior iris surface as the feature points and generate the tilt information based on the at least two points.

[0027] Some exemplary aspects are a method for controlling an ophthalmic device including a fixation target presentation unit that presents a fixation target to a subject, a scanning unit that applies an optical coherence tomography (OCT) scan to an anterior segment of the subject's eye, and at least one processor, wherein the at least one processor is caused to perform the steps of constructing an image based on data collected by the scanning unit, generating tilt information indicating the tilt state of the anterior segment depicted in the image, and controlling the fixation target presentation unit based on the tilt information.

[0028] Some exemplary aspects are a method for controlling an ophthalmic device including a fixation target presentation unit that presents a fixation target to a subject, a scanning unit that applies an optical coherence tomography (OCT) scan to the anterior segment of the subject's eye, an operating unit that generates a signal in response to an operation, and at least one processor, wherein the at least one processor is caused to perform the steps of constructing an image based on data collected by the scanning unit, generating tilt information indicating the tilt state of the anterior segment depicted in the image, displaying information based on the tilt information on a display means, and controlling the fixation target presentation unit based on the signal from the operating unit.

[0029] Some exemplary aspects are programs that cause a computer to execute the method of any of the exemplary aspects.

[0030] Some exemplary embodiments are a computer-readable non-transitory recording medium having a program according to any of the exemplary embodiments recorded thereon. [Effects of the Invention]

[0031] Exemplary embodiments allow for improved OCT anterior segment analysis. [Brief explanation of the drawings]

[0032] [Figure 1] 1 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an exemplary embodiment. [Figure 2]1 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an exemplary embodiment. [Figure 3] 1 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an exemplary embodiment. [Figure 4] 1 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an exemplary embodiment. [Figure 5A] 1 is a schematic diagram for explaining an example of processing executed by an ophthalmologic apparatus according to an exemplary aspect. [Figure 5B] 1 is a schematic diagram for explaining an example of processing executed by an ophthalmologic apparatus according to an exemplary aspect. [Figure 6A] 1 is a schematic diagram for explaining an example of processing executed by an ophthalmologic apparatus according to an exemplary aspect. [Figure 6B] 1 is a schematic diagram for explaining an example of processing executed by an ophthalmologic apparatus according to an exemplary aspect. [Figure 7A] 1 is a schematic diagram for explaining an example of processing executed by an ophthalmologic apparatus according to an exemplary aspect. [Figure 7B] 1 is a schematic diagram for explaining an example of processing executed by an ophthalmologic apparatus according to an exemplary aspect. [Figure 8] 10 is a flowchart illustrating an example of the operation of an ophthalmologic apparatus according to an exemplary embodiment. [Figure 9] 10 is a flowchart illustrating an example of the operation of an ophthalmologic apparatus according to an exemplary embodiment. [Figure 10] 10 is a flowchart illustrating an example of the operation of an ophthalmologic apparatus according to an exemplary embodiment. [Figure 11] 10A and 10B are schematic diagrams for explaining the effects of an ophthalmologic apparatus according to an exemplary embodiment. [Figure 12] 1 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an exemplary embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0033] Ophthalmic devices, control methods thereof, programs, and recording media according to several exemplary embodiments will be described in detail with reference to the drawings. Any matter disclosed in the documents cited in this specification or any matter related to other known technologies can be combined with the exemplary embodiments. Unless otherwise specified, no distinction is made between "image data" and an "image" based on the image data, nor between a "region" of the subject's eye and the "image" thereof.

[0034] An ophthalmic device according to some exemplary embodiments can measure the anterior segment of a living eye using Fourier domain OCT (e.g., swept-source OCT). The type of OCT applicable to the exemplary embodiments is not limited to swept-source OCT, and may be, for example, spectral domain OCT or time domain OCT.

[0035] Ophthalmic devices according to some exemplary embodiments may be capable of processing images acquired by modalities other than OCT. For example, some exemplary embodiments may be capable of processing images acquired by any of a fundus camera, a scanning laser ophthalmoscope (SLO), a slit lamp microscope, and an ophthalmic surgical microscope. Ophthalmic devices according to some exemplary embodiments may include any of a fundus camera, an SLO, a slit lamp microscope, and an ophthalmic surgical microscope.

[0036] An ophthalmic device according to an exemplary embodiment is configured to acquire and process an image (anterior segment image) constructed based on data collected from the anterior segment of a living eye by an OCT scan.

[0037] The ophthalmic device of exemplary embodiments has a configuration for applying an OCT scan to the anterior segment of a living eye to collect data and a configuration for constructing an anterior segment image based on the collected data. Furthermore, some exemplary embodiments of the ophthalmic device may have a function for externally receiving an anterior segment image of a living eye. For example, an anterior segment image of a living eye is acquired using an OCT device and stored in a medical image management system (e.g., Picture Archiving and Communication Systems; PACS). Some exemplary embodiments of the ophthalmic device are configured to access the medical image management system to receive the anterior segment image.

[0038] In the following disclosure, in addition to such an ophthalmic apparatus, a control method for the ophthalmic apparatus, a program for causing a computer to execute this control method, and a recording medium on which this program is recorded will be described.

[0039] At least a portion of the functionality of the elements disclosed herein is implemented using circuitry or processing circuitry, such as a general-purpose processor, a special-purpose processor, an integrated circuit, a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), a field programmable gate array (FPGA)), or a combination of these devices configured and / or programmed to perform at least a portion of the disclosed functionality. The term "circuitry," "unit," "means," or the like refers to hardware that performs at least a portion of the disclosed functions or that is programmed to perform at least a portion of the disclosed functions. The hardware may be the hardware disclosed herein or may be known hardware that is programmed and / or configured to perform at least a portion of the described functions. In the case of a processor, where the hardware can be considered a type of circuitry, the term "circuitry," "unit," "means," or the like refers to a combination of hardware and software, where the software is used to configure the hardware and / or the processor.

[0040] <Configuration of ophthalmic equipment> The ophthalmic apparatus 1 of the exemplary embodiment shown in FIG. 1 is a multifunction device combining an OCT device and a fundus camera, and has the functions of applying OCT to the anterior segment Ea of the subject's eye E and photographing the anterior segment Ea. The ophthalmic apparatus 1 includes a fundus camera unit 2, an OCT unit 100, and an arithmetic and control unit 200. The fundus camera unit 2 is provided with various elements (e.g., optical systems, mechanisms, etc.) for acquiring a front image of the subject's eye. The OCT unit 100 is provided with some of the various elements (e.g., optical systems, mechanisms, etc.) for performing OCT scanning. Other elements for performing OCT scanning are provided in the fundus camera unit 2. The arithmetic and control unit 200 includes one or more processors and one or more storage devices configured to perform various processes (e.g., calculations, controls, etc.). In addition to these, the ophthalmic apparatus 1 includes optional elements and units such as members for supporting the subject's face (e.g., a chin rest, a forehead rest, etc.) and attachments for switching the area to which the OCT scan is applied.

[0041] An example of an attachment for switching the OCT scan application site will be described. This attachment includes a lens group (lens unit). The anterior segment OCT attachment 400 provided in the ophthalmologic apparatus 1 of this example includes a lens group for switching the OCT scan application site between the posterior segment (fundus Ef) and the anterior segment Ea. The anterior segment OCT attachment 400 may be configured similarly to the optical unit disclosed in, for example, Japanese Patent Application Laid-Open No. 2015-160103.

[0042] As shown in Fig. 1, the anterior segment OCT attachment 400 can be placed between the objective lens 22 and the subject's eye E. When the anterior segment OCT attachment 400 is placed in the optical path, the ophthalmic apparatus 1 can apply OCT scanning to the anterior segment Ea. On the other hand, when the anterior segment OCT attachment 400 is retracted from the optical path, the ophthalmic apparatus 1 can apply OCT scanning to the posterior segment. The anterior segment OCT attachment 400 is moved manually or automatically.

[0043] In some exemplary embodiments, the ophthalmic device may be capable of applying an OCT scan to the posterior segment of the eye when the attachment is disposed in the optical path, and may be capable of applying an OCT scan to the anterior segment of the eye when the attachment is retracted from the optical path. Furthermore, the OCT scan application site switched by the attachment is not limited to a combination of the posterior segment and the anterior segment, but may be a combination of any other site of the eye. The configuration for switching the OCT scan application site is not limited to such an attachment (lens group, lens unit, optical unit), and may be, for example, a configuration including one or more lenses movable along the optical path.

[0044] <Fundus camera unit 2> The fundus camera unit 2 is provided with elements (optical system, mechanism, etc.) for photographing the subject's eye E (anterior segment Ea, fundus Ef, etc.) and acquiring a digital photograph. The acquired digital photograph of the subject's eye E is a front image such as an observed image or a photographed image. The observed image is obtained by, for example, video shooting using near-infrared light, and is used for alignment, focusing, tracking, etc. The photographed image is a still image obtained using, for example, flash light in the visible or infrared range, and is used for diagnosis, analysis, etc.

[0045] The fundus camera unit 2 includes an illumination optical system 10 and an imaging optical system 30. The illumination optical system 10 irradiates illumination light onto the subject's eye E. The imaging optical system 30 detects return light of the illumination light from the subject's eye E. The measurement light from the OCT unit 100 is guided to the subject's eye E through an optical path within the fundus camera unit 2, and the return light is guided to the OCT unit 100 through the same optical path.

[0046] Light (observation illumination light) output from an observation light source 11 of an illumination optical system 10 is reflected by a concave mirror 12, passes through a condenser lens 13, and is transmitted through a visible light cut filter 14 to become near-infrared light. The observation illumination light is then focused near an imaging light source 15, reflected by a mirror 16, and passes through a relay lens system 17, a relay lens 18, an aperture 19, and a relay lens system 20. The observation illumination light is then reflected by the peripheral portion (the area surrounding the hole) of a perforated mirror 21, passes through a dichroic mirror 46, and is refracted by an objective lens 22 to illuminate the subject's eye E. Return light of the observation illumination light from the subject's eye E is refracted by the objective lens 22, passes through the dichroic mirror 46, passes through a hole formed in the central area of ​​the perforated mirror 21, passes through a dichroic mirror 55, passes through an imaging focusing lens 31, and is reflected by a mirror 32. Furthermore, this returned light passes through the half mirror 33A, is reflected by the dichroic mirror 33, and is imaged on the light receiving surface of the image sensor 35 by the imaging lens 34. The image sensor 35 detects the returned light at a predetermined frame rate. The focus (focal position) of the photographing optical system 30 is typically adjusted to match the fundus Ef or the anterior segment Ea.

[0047] Light output from the imaging light source 15 (imaging illumination light) travels along the same path as the observation illumination light and is irradiated onto the subject's eye E. Return light of the imaging illumination light from the subject's eye E travels along the same path as the return light of the observation illumination light and is guided to the dichroic mirror 33, passes through the dichroic mirror 33, is reflected by a mirror 36, and is imaged by an imaging lens 37 on the light-receiving surface of an image sensor 38.

[0048] 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 33A, reflected by the mirror 32, passes through the photographing focusing lens 31 and the dichroic mirror 55, and passes through the hole in the aperture mirror 21. The light beam that has passed through the hole in the aperture mirror 21 passes through the dichroic mirror 46, is refracted by the objective lens 22, and is projected onto the fundus Ef.

[0049] The fixation position of the subject's eye E based on the fixation target can be changed by changing the display position of the fixation target image on the screen of the LCD 39. In other words, by changing the fixation position, the line of sight of the subject's eye E can be guided in a desired direction. A graphical user interface (GUI) or the like can be provided for specifying the desired fixation position.

[0050] The configuration for presenting a fixation target with a changeable fixation position to the subject's eye E is not limited to a display device such as an LCD. For example, a fixation matrix in which a plurality of light-emitting elements (such as light-emitting diodes) are arranged in a matrix (array) can be used instead of the display device. In this case, the fixation position can be changed by selectively turning on the plurality of light-emitting elements. As yet another example, a configuration in which the fixation position is changed by one or more movable light-emitting elements can be used.

[0051] The alignment optical system 50 generates an alignment index used to align the optical system with the subject's eye E. Alignment light output from a light-emitting diode (LED) 51 passes through an aperture 52, an aperture 53, and a relay lens 54, is reflected by a dichroic mirror 55, passes through the hole in the aperture mirror 21, transmits through the dichroic mirror 46, and is projected onto the subject's eye E via the objective lens 22. The return light of the alignment light from the subject's eye E is guided to the image sensor 35 via the same path as the return light of the observation illumination light. Manual alignment or automatic alignment can be performed based on the received light image (alignment index image).

[0052] As in the conventional example, the alignment index image in this example consists of two bright spot images whose positions change depending on the alignment state. When the relative position between the subject's eye E and the optical system changes in the x and y directions, the two bright spot images displace together in the x and y directions. When the relative position between the subject's eye E and the optical system changes in the z direction, the relative position (distance) between the two bright spot images changes. When the distance between the subject's eye E and the optical system in the z direction matches the predetermined working distance, the two bright spot images overlap. When the position of the subject's eye E matches the position of the optical system in the x and y directions, two bright spot images are presented within or near a specified alignment target. When the distance between the subject's eye E and the optical system in the z direction matches the working distance and the position of the subject's eye E matches the position of the optical system in the x and y directions, the two bright spot images overlap and are presented within the alignment target.

[0053] In auto-alignment, the data processing unit 230 detects the positions of the two bright spot images, and the main control unit 211 controls the moving mechanism 150 (described later) based on the positional relationship between the two bright spot images and the alignment target. In manual alignment, the main control unit 211 displays the two bright spot images together with the observed image of the subject's eye E on the display unit 241, and the user operates the moving mechanism 150 using the operation unit 242 while referring to the two displayed bright spot images.

[0054] The alignment method is not limited to the above. The alignment means of some exemplary embodiments of the ophthalmologic apparatus may be configured to acquire two or more images by photographing the anterior segment of the eye from different directions substantially simultaneously, analyze the photographed images to determine the three-dimensional position of the subject's eye, and move the optical system based on the three-dimensional position (see, for example, Japanese Patent Application Laid-Open No. 2013-248376).

[0055] The focusing optical system 60 generates a split index used for focus adjustment of the subject's eye E. The focusing optical system 60 moves along the optical path (illumination optical path) of the illumination optical system 10 in conjunction with movement of the photographing focusing lens 31 along the optical path (photographing optical path) of the photographing optical system 30. The reflecting rod 67 is inserted into and removed from the illumination optical path. When performing focus adjustment, the reflecting surface of the reflecting rod 67 is tilted and positioned in the illumination optical path. Focusing light output from the LED 61 passes through the relay lens 62, is split into two beams by the split index plate 63, passes through the two-hole diaphragm 64, is reflected by the mirror 65, and is first imaged and reflected on the reflecting surface of the reflecting rod 67 by the condenser lens 66. The focusing light then passes through the relay lens 20, is reflected by the aperture mirror 21, passes through the dichroic mirror 46, and is projected onto the subject's eye E via the objective lens 22. The return light of the focusing light from the subject's eye E passes through the same path as the return light of the alignment light and is guided to the image sensor 35. Manual focusing or autofocusing can be performed based on the received light image (split target image).

[0056] Diopter correction lenses 70 and 71 can be selectively inserted into the photographing optical path between the aperture mirror 21 and the dichroic mirror 55. The diopter correction lens 70 is a plus lens (convex lens) for correcting severe hyperopia. The diopter correction lens 71 is a minus lens (concave lens) for correcting severe myopia.

[0057] The dichroic mirror 46 couples the OCT optical path (measurement arm) to the digital imaging optical path (illumination optical path and imaging optical path). The dichroic mirror 46 reflects light in the wavelength band for OCT scanning and transmits light in the wavelength band for imaging. The measurement arm is provided with, in order from the OCT unit 100 side, 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.

[0058] The retroreflector 41 is movable in the directions indicated by the arrows in Fig. 1 (the incident and exit directions of the measurement light LS). This changes the length of the measurement arm. Changing the measurement arm length is used, for example, to correct the optical path length according to the axial length of the eye, the shape of the cornea, or the shape of the fundus, or to adjust the interference state.

[0059] The dispersion compensation member 42, together with a dispersion compensation member 113 (described later) disposed in the reference arm, acts to match the dispersion characteristics of the measurement light LS with the dispersion characteristics of the reference light LR.

[0060] The OCT focusing lens 43 is movable along the direction indicated by the arrow in Fig. 1 (the optical axis of the measurement arm) to adjust the focus of the measurement arm. This changes the focus state (focal position, focal length) of the measurement arm. The ophthalmologic apparatus 1 may be capable of cooperatively controlling 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.

[0061] The optical scanner 44 is disposed substantially at a position optically conjugate with the pupil of the subject's eye E. The optical scanner 44 deflects the measurement light LS guided by the measurement arm. The optical scanner 44 is, for example, a deflector capable of two-dimensional scanning, including a deflector (x-scanner) for scanning in the x-direction and a deflector (y-scanner) for scanning in the y-direction. For example, the optical scanner 44 is a galvanometer scanner including two galvanometer mirrors. Typically, one of the two deflectors is disposed at a position optically conjugate with the pupil of the subject's eye E, or a pupil-conjugate position is disposed between the two deflectors. This allows the measurement light LS to be pivoted at a position within (or near) the pupil of the subject's eye E when applying an OCT scan to the fundus Ef, thereby enabling the OCT scan to be applied to a wide range of the fundus Ef.

[0062] In this embodiment, when the anterior segment OCT attachment 400 is retracted from the measurement arm, as described above, the optical scanner 44 is substantially positioned optically conjugate with the pupil of the subject's eye E. On the other hand, when the anterior segment OCT attachment 400 is inserted into the measurement arm, the optical scanner 44 is positioned optically conjugate with a position between the anterior segment Ea and the anterior segment OCT attachment 400. More specifically, when the anterior segment OCT attachment 400 is retracted from the measurement arm, for example, either one of the x-scanner and the y-scanner is positioned optically conjugate with the pupil, or a position between the x-scanner and the y-scanner is positioned optically conjugate with the pupil. Furthermore, when the anterior segment OCT attachment 400 is inserted into the measurement arm, for example, either the x-scanner or the y-scanner is positioned optically conjugate to the position between the anterior segment Ea and the anterior segment OCT attachment 400, or the position between the x-scanner and the y-scanner is positioned optically conjugate to the position between the anterior segment Ea and the anterior segment OCT attachment 400.

[0063] <OCTユニット100> The exemplary OCT unit 100 shown in FIG. 2 is provided with optical systems and mechanisms for applying swept-source OCT. This optical system includes an interference optical system. This interference optical system splits light from a wavelength-tunable light source (swept-wavelength light source) into measurement light and reference light, superimposes the measurement light returned from the subject's eye E with the reference light that has passed through the reference optical path, and generates interference light, which is then detected. The detection result (detection signal) obtained by the interference optical system is a signal (interference signal) representing the spectrum of the interference light, and is sent to the arithmetic and control unit 200 (image construction unit 220).

[0064] Light source unit 101 includes, for example, a near-infrared wavelength-tunable laser that changes the wavelength of output light at high speed. Light L0 output from light source unit 101 is guided by optical fiber 102 to polarization controller 103, where its polarization state is adjusted. Light L0 is further guided by optical fiber 104 to fiber coupler 105, where it is split into measurement light LS and reference light LR. The optical path of measurement light LS is called a measurement arm, and the optical path of reference light LR is called a reference arm.

[0065] The reference light LR is guided by an optical fiber 110 to a collimator 111, where it is converted into a parallel beam, and then guided to a retroreflector 114 via an optical path length correction element 112 and a dispersion compensation element 113. The optical path length correction element 112 is an optical element for matching the optical path length of the reference light LR with that of the measurement light LS. The dispersion compensation element 113, together with a dispersion compensation element 42 arranged in the measurement arm, acts to match the dispersion characteristics between the reference light LR and the measurement light LS. The retroreflector 114 is movable along the optical path of the reference light LR incident thereon, thereby changing the length of the reference arm. Changing the reference arm length is used, for example, to correct the optical path length according to the axial length of the eye, the shape of the cornea or the fundus, or to adjust the interference state.

[0066] The reference light LR that has passed through the retroreflector 114 passes through a dispersion compensation member 113 and an optical path length correction member 112, is converted from a parallel beam into a focused beam by a collimator 116, and enters an optical fiber 117. The reference light LR that has entered the optical fiber 117 is guided to a polarization controller 118, where its polarization state is adjusted. The polarization controller 118 is an optical member for adjusting the interference state, and is used, for example, to optimize the interference intensity between the measurement light LS and the reference light LR. The reference light LR that has passed through the polarization controller 118 is guided through an optical fiber 119 to an attenuator 120, where its light amount is adjusted, and is then guided through an optical fiber 121 to a fiber coupler 122.

[0067] On the other hand, the measurement light LS generated by the fiber coupler 105 is guided through the optical fiber 127 to the collimator lens unit 40 and converted into a parallel beam. The measurement light LS emitted from the collimator lens unit 40 passes through a retroreflector 41, a dispersion compensation member 42, an OCT focusing lens 43, an optical scanner 44, and a relay lens 45, is reflected by a dichroic mirror 46, is refracted by the objective lens 22, and is projected onto the subject's eye E. When the anterior segment OCT attachment 400 is disposed on the measurement arm, the measurement light LS reflected by the dichroic mirror 46 is projected onto the subject's eye E (anterior segment Ea) via the objective lens 22 and the anterior segment OCT attachment 400. The measurement light LS is scattered and reflected at various depth positions in the subject's eye E. The returning light of the measuring light LS from the eye E travels in the opposite direction along the same path as the outward path, is guided to the fiber coupler 105 , and reaches the fiber coupler 122 via the optical fiber 128 .

[0068] The fiber coupler 122 generates interference light by superimposing the measurement light LS incident via the optical fiber 128 and the reference light LR incident via the optical fiber 121. The fiber coupler 122 splits the generated interference light at a predetermined splitting ratio (for example, 1:1) to generate a pair of interference lights LC. The pair of interference lights LC are guided to the detector 125 via optical fibers 123 and 124, respectively.

[0069] The detector 125 includes, for example, a balanced photodiode. The balanced photodiode has a pair of photodetectors that respectively detect a pair of interference lights LC, and outputs the difference between the pair of detection results obtained by these. The detector 125 sends this output (detection signal) to a data acquisition system (DAQ) 130.

[0070] A clock KC is supplied to the data collection system 130 from the light source unit 101. The clock KC is generated in the light source unit 101 in synchronization with the output timing of each wavelength swept within a predetermined wavelength range by the wavelength-tunable light source. The light source unit 101, for example, branches the light L0 of each output wavelength to generate two branched lights, optically delays one of the branched lights, combines the branched lights, detects the resulting combined light, and generates the clock KC based on the detection result. The data collection system 130 samples the detection signal input from the detector 125 based on the clock KC. The data collection system 130 sends the sampling result to the arithmetic and control unit 200.

[0071] In this example, both an element for changing the measurement arm length (e.g., retroreflector 41) and an element for changing the reference arm length (e.g., retroreflector 114 or reference mirror) are provided, but only one of these elements may be provided. Furthermore, the element for changing the difference between the measurement arm length and the reference arm length (optical path length difference) is not limited to these and may be any element (optical member, mechanism, etc.).

[0072] In this way, swept-source OCT is a technique in which light from a tunable light source is split into measurement light and reference light, the return light of the measurement light from the test object is superimposed on the reference light to generate interference light, this interference light is detected by a photodetector, and an image is constructed by applying a Fourier transform or the like to the detection data collected in response to the wavelength sweep and the scanning of the measurement light.

[0073] On the other hand, spectral domain OCT is a technique in which light from a low-coherence light source (broadband light source) is split into measurement light and reference light, and the return light from the test object is superimposed on the reference light to generate interference light. The spectral distribution of this interference light is detected using a spectroscope, and an image is constructed by applying a Fourier transform or other process to the detected spectral distribution.

[0074] That is, swept-source OCT is an OCT method that acquires the spectral distribution of interference light in a time-division manner, and spectral-domain OCT is an OCT method that acquires the spectral distribution of interference light in a space-division manner.

[0075] <Control system / processing system> 3 shows an example of the configuration of the control system and processing system of the ophthalmic apparatus 1. The control unit 210, the image construction unit 220, and the data processing unit 230 are provided in, for example, an arithmetic control unit 200. The ophthalmic apparatus 1 may include a communication device for performing data communication with an external device. The ophthalmic apparatus 1 may also include a drive device (reader / writer) for reading data from a recording medium and writing data to a recording medium.

[0076] <Control unit 210> The control unit 210 executes various controls. The control unit 210 includes a main control unit 211 and a storage unit 212. The main control unit 211 includes a processor and controls each element of the ophthalmologic apparatus 1 (including the elements shown in FIGS. 1 to 4). The main control unit 211 controls the LCD 39 to perform control related to the fixation target. The main control unit 211 is realized by cooperation between hardware including the processor and control software.

[0077] The imaging focusing driver 31A moves the imaging focusing lens 31 arranged in the imaging optical path and the focus optical system 60 arranged in the illumination optical path under the control of the main controller 211. The retroreflector (RR) driver 41A moves the retroreflector 41 provided in the measurement arm under the control of the main controller 211. The OCT focusing driver 43A moves the OCT focusing lens 43 arranged in the measurement arm under the control of the main controller 211. The retroreflector (RR) driver 114A moves the retroreflector 114 arranged in the reference arm under the control of the main controller 211. Each of the above drivers includes an actuator such as a pulse motor that operates under the control of the main controller 211. The optical scanner 44 provided in the measurement arm operates under the control of the main controller 211.

[0078] The movement mechanism 150, for example, moves at least the fundus camera unit 2 three-dimensionally. In a typical example, the movement mechanism 150 includes an x-stage movable in ±x directions (left and right directions), an x-movement mechanism for moving the x-stage, a y-stage movable in ±y directions (up and down directions), a y-movement mechanism for moving the y-stage, a z-stage movable in ±z directions (depth direction), and a z-movement mechanism for moving the z-stage. Each of these movement mechanisms includes an actuator such as a pulse motor that operates under the control of the main controller 211.

[0079] The insertion / removal mechanism 400A performs an operation of inserting the anterior segment OCT attachment 400 into the OCT optical path (measurement arm) and an operation of retracting the anterior segment OCT attachment 400 from the measurement arm. The insertion / removal mechanism 400A includes an actuator such as a solenoid actuator that operates under the control of the main controller 211.

[0080] The storage unit 212 stores various types of data. The data stored in the storage unit 212 includes OCT images, digital photographs (anterior eye images, fundus images), information about the subject's eye, analysis data, etc. The information about the subject's eye includes subject information such as patient ID and name, identification information for the left eye / right eye, electronic medical record information, etc.

[0081] <Image construction unit 220> The image constructing unit 220 includes a processor and constructs OCT image data of the subject's eye E based on signals (sampling data) input from the data collection system 130. The OCT image data constructed by the image constructing unit 220 is one or more A-scan image data, and is typically B-scan image data (two-dimensional cross-sectional image data) made up of a plurality of A-scan image data.

[0082] The process of constructing OCT image data includes, as in conventional Fourier domain OCT, noise removal (noise reduction), filtering, fast Fourier transform (FFT), etc. In the case of other types of OCT devices, the image constructing unit 220 performs known processes according to the type.

[0083] The image constructing unit 220 may be configured to construct three-dimensional data of the subject's eye E based on a signal input from the data collection system 130. This three-dimensional data is three-dimensional image data that represents a three-dimensional region (volume) of the subject's eye E. This three-dimensional image data means image data in which pixel positions are defined by a three-dimensional coordinate system. Examples of three-dimensional image data include stack data and volume data.

[0084] Stack data is image data obtained by arranging multiple cross-sectional images obtained along multiple scan lines three-dimensionally based on the positional relationships of these scan lines. That is, stack data is image data constructed by expressing multiple cross-sectional images originally defined by individual two-dimensional coordinate systems in a single three-dimensional coordinate system (i.e., embedding them in a single three-dimensional space). In other words, stack data is image data obtained by arranging multiple A-scan image data acquired for multiple two-dimensionally arranged scan points (scan point array) three-dimensionally based on the positional relationships of these scan points.

[0085] Volume data, also known as voxel data, is image data with pixels consisting of three-dimensionally arranged voxels. Volume data is constructed by applying interpolation and voxelization processes to stack data.

[0086] The image constructor 220 constructs a display image by rendering the 3D image data. Examples of applicable rendering methods include volume rendering, surface rendering, maximum intensity projection (MIP), minimum intensity projection (MIP), and multiplanar reconstruction (MPR).

[0087] The image constructing unit 220 may be configured to construct an OCT en-face image based on the three-dimensional image data. For example, the image constructing unit 220 can construct projection data by projecting the three-dimensional image data in the z direction (A-line direction, depth direction). The image constructing unit 220 can also construct projection data from a portion of the three-dimensional image data (e.g., a slab).

[0088] Partial data (e.g., slabs) of the three-dimensional image data are typically set using segmentation. Segmentation is a process for identifying partial regions in an image. Typically, segmentation is used to identify an image region corresponding to a specific tissue of the subject's eye E. Segmentation may include any known image processing technique, and may include, for example, image processing such as edge detection and / or segmentation using machine learning (e.g., deep learning). Segmentation is performed, for example, by the image constructor 220 or the data processor 230.

[0089] The ophthalmologic apparatus 1 may be capable of performing OCT motion contrast imaging. OCT motion contrast imaging is an imaging technique that extracts the movement of fluid or the like present in the eye (see, for example, JP-A-2015-515894).

[0090] The image construction unit 220 is realized by the cooperation of hardware including a processor and image construction software.

[0091] <Data processing unit 230> The data processing unit 230 includes a processor and is configured to apply specific data processing to the image of the subject's eye E. The data processing unit 230 is realized, for example, by cooperation between hardware including a processor and data processing software.

[0092] The data processing unit 230 can perform registration between two images acquired of the subject's eye E. For example, the data processing unit 230 can perform registration between three-dimensional image data acquired using an OCT scan and a front image acquired by the fundus camera unit 2. The data processing unit 230 can also perform registration between two OCT images acquired using an OCT scan. The data processing unit 230 can also perform registration between two front images acquired by the fundus camera unit 2. It is also possible to apply registration to the analysis results of the OCT images and the analysis results of the front images. Registration can be performed by a known method, and includes, for example, feature point extraction and affine transformation.

[0093] <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 that combines a display function and an operation function, such as a touch panel. It is also possible to construct an embodiment that does not include at least a part of the user interface 240. For example, the display device may be an external device connected to the ophthalmologic apparatus.

[0094] <Details of the control and processing systems> An example of the detailed configuration of the control system and processing system of the ophthalmic apparatus 1 is shown in Fig. 4. In Fig. 4, elements relating to characteristic control and processing of the ophthalmic apparatus 1 are selectively shown.

[0095] <lcd39> The LCD 39 presents a fixation target to the eye E to be examined. The LCD 39 is an example of a fixation target presenting unit. Fixation target presenting units in other embodiments present a fixation target to the eye to be examined (the eye to which the OCT scan is applied) by a configuration other than a display device such as an LCD. Still other embodiments of the fixation target presenting unit present a fixation target to the fellow eye of the eye to be examined. An example of such a fixation target presenting unit is an external fixation lamp.

[0096] <OCT unit 250> The OCT unit 250 applies an OCT scan to the anterior eye segment Ea to construct an image. The OCT unit 250 includes a group of elements for applying an OCT scan to the anterior eye segment Ea and an element (group) for constructing an image from the data collected by the OCT scan. In this embodiment, the OCT unit 250 includes a group of elements forming a measurement arm in the fundus camera unit 2, the OCT unit 100, and the image construction unit 220.

[0097] <Tilt information generation unit 231> The data processing unit 230 of this embodiment includes a tilt information generation unit 231. The tilt information generation unit 231 generates tilt information indicating the tilt state of the anterior eye segment Ea depicted in the image constructed by the OCT unit 250.

[0098] Exemplary tilt information may include information indicating the orientation of the anterior eye segment Ea. This orientation information may include, for example, a value of an angle. This angle may be, for example, a tilt angle with respect to a predetermined direction (reference direction) in a coordinate system in which the image is defined. This coordinate system may be, for example, a three-dimensional coordinate system (e.g., an xyz coordinate system), or a defined coordinate system of a subspace (three-dimensional space, two-dimensional space, or one-dimensional space) of the space spanned by the three-dimensional coordinate system.

[0099] In a typical example, the reference direction is the z direction or a direction perpendicular to the z direction (any direction in the xy plane), and the tilt information includes the tilt angle with respect to this reference direction. The tilt angle with respect to the reference direction is defined, for example, as an angle value when the angle value of the reference direction is 0 degrees or 0 radians. Furthermore, the tilt angle with respect to the reference direction may be information including both magnitude and direction (positive direction, negative direction), or may be information of magnitude only (absolute value).

[0100] Several examples of processing performed by the tilt information generating unit 231 will be described. For example, the tilt information generating unit 231 may be configured to perform processing to analyze an image constructed by the OCT unit 250 to identify one or more feature points and processing to generate tilt information based on the identified feature points. Note that the processing performed by the tilt information generating unit 231 is not limited to the processing in this example. For example, the tilt information generating unit 231 may be configured to generate tilt information directly from the image constructed by the OCT unit 250 using an artificial intelligence engine (typically, an inference system including a machine-learned convolutional neural network) trained to generate tilt information from an image.

[0101] The feature point may include, for example, any of the points on the angle of the eye, the apex of the anterior lens, the apex of the cornea, and the anterior surface of the iris. However, the feature point is not limited to these. For example, the feature point may be any of the ciliary body (ciliary muscle), the zonules of Zinn, the vitreous body, and the fundus Ef, or a part thereof. The feature point may also be an artificial object implanted in the eye, or a part thereof. Examples of artificial objects include an intraocular lens (IOL), a minimally invasive glaucoma surgery (MIGS) device, etc.

[0102] Image analysis for identifying feature points may include, for example, segmentation for identifying an image region corresponding to a predetermined portion of the anterior segment Ea, feature point detection for identifying a characteristic portion (feature point) in a given image region, etc. Segmentation may include any known image processing technique, such as image processing such as edge detection and / or segmentation using machine learning (e.g., deep learning).

[0103] Several examples of processes for generating tilt information based on feature points will be described. The process for generating tilt information from a feature point in a certain image region may include, for example, a process for determining the tilt of a tangent line or a tangent plane (e.g., the tilt of a normal line) at the feature point and a process for generating tilt information from the tilt. The tilt information may be a tilt value or a value calculated from the tilt. Note that the image region is differentiable at least in the vicinity of the feature point. For example, before determining the tangent line or tangent plane, the target image region (at least in the vicinity of the feature point) can be approximated by a differentiable figure (such as a line, curve, plane, or curved surface). Alternatively, the target image region may be approximated by a differentiable figure and then the feature point may be identified.

[0104] The process of generating gradient information from two or more feature points may include, for example, a process of determining the gradient of a line or a plane (e.g., the gradient of a normal) passing through two or more feature points, and a process of generating gradient information from this gradient. The gradient information may be a gradient value or a value calculated from the gradient. The image region to which the process of this example is applied does not need to be differentiable. Furthermore, instead of considering a figure (a line or a plane) passing through two or more feature points, an approximate figure obtained from two or more feature points (e.g., a figure obtained by any regression analysis such as the least squares method) may be considered.

[0105] An example in which the feature point is an angle of the eye will be described. In this example, the OCT unit 250 applies OCT scanning to a region including at least two points in the angle of the eye E. Here, "at least two points in the angle of the eye" may be any multiple points, but typically includes a pair of opposing points on the angle of the eye that are distributed in a substantially circular shape.

[0106] The OCT scan in this example may be, for example, any of a B scan, a 3D scan, and a radial scan. The B scan in this example may be, for example, the ATA scan described above. The region to which the 3D scan in this example is applied may be, for example, a volume whose center in the x and y directions is the corneal apex, the pupil center, or a position nearby. The radial scan (or cross scan) in this example may include, for example, multiple B scans with different orientations that intersect at the corneal apex, the pupil center, or a position nearby. The OCT unit 250 in this example further constructs an image from the data collected in the OCT scan in this example.

[0107] The gradient information generating unit 231 of this example first analyzes the image constructed by the OCT unit 250 to identify at least two points of the above-mentioned angle as feature points. For example, the gradient information generating unit 231 applies segmentation to the image constructed by the OCT unit 250 to identify an image region corresponding to the cornea (corneal image) and an image region corresponding to the iris (iris image). For example, the corneal image is an image region corresponding to the posterior surface of the cornea (posterior corneal image), and the iris image is an image region corresponding to the anterior surface of the iris (anterior iris image). The gradient information generating unit 231 can identify a point where the corneal image (e.g., posterior corneal image) and the iris image (e.g., anterior iris image) intersect with each other and set the point as the angle.

[0108] Furthermore, the inclination information generating unit 231 of this example generates inclination information based on at least two points of the corner angle identified as feature points. First to third examples of this inclination information generation will be described below, but the present invention is not limited to these.

[0109] In a first example, the inclination information generating unit 231 determines the inclination of a line connecting two points of the corner angle identified as feature points, and can use this inclination value or a value calculated from it as inclination information (inclination angle).

[0110] In the second example, when a radial scan or a three-dimensional scan is applied, the tilt information generating unit 231 can obtain a plurality of pairs of opposing points, obtain the tilt of a line connecting each pair of opposing points, and generate tilt information from the obtained plurality of tilts (by statistical processing). As a specific example, the tilt information generating unit 231 can identify the maximum value from the plurality of tilt values, and use this maximum value or a value calculated from it as tilt information (tilt angle).

[0111] In a third example, when a radial scan or a three-dimensional scan is applied, the tilt information generating unit 231 identifies three or more feature points, calculates the tilt of a plane defined using these feature points (for example, the tilt of the normal), and can use this tilt value or a value calculated from it as tilt information (tilt angle).

[0112] A specific example in which the feature point is an iridocorneal angle will be described with reference to FIGS. 5A and 5B. First, the gradient information generating unit 231 applies segmentation to the image obtained by the ATA scan to identify corneal posterior surface images 511 and 512 and iris anterior surface images 521 and 522 shown in FIG. 5A. The corneal posterior surface image 511 and the iris anterior surface image 521 are located on the left side of the image frame, while the corneal posterior surface image 512 and the iris anterior surface image 522 are located on the right side of the image frame. Next, the gradient information generating unit 231 identifies the position where the corneal posterior surface image 511 and the iris anterior surface image 521 intersect, and sets this intersection position as the iridocorneal angle feature point 531 (see FIG. 5B). Similarly, the gradient information generating unit 231 identifies the position where the corneal posterior surface image 512 and the iris anterior surface image 522 intersect, and sets this intersection position as the iridocorneal angle feature point 532 (see FIG. 5B). Feature point 531 is located on the left edge of the image frame, and feature point 532 is located on the right edge of the image frame. Finally, the tilt information generating unit 231 calculates the tilt of a line 540 connecting feature point 531 and feature point 532, and sets the value of this tilt (or a value calculated from it) as the tilt angle (see FIG. 5B ). The tilt angle generated in this manner is an example of tilt information that indicates the tilt state of the anterior eye segment Ea when the ATA scan is applied.

[0113] An example in which the feature point is the apex of the anterior surface of the lens will be described. In this example, the OCT unit 250 applies an OCT scan to a region including the apex of the anterior surface of the lens (or a position nearby). The OCT scan in this example may be, for example, a B-scan, a three-dimensional scan, or a radial scan. The B-scan in this example may be, for example, the ATA scan described above. The region to which the three-dimensional scan in this example is applied may be, for example, a volume whose center in the x and y directions is the apex of the anterior surface of the lens or a position nearby. The radial scan (or cross scan) in this example may include, for example, multiple B-scans with different orientations that intersect at the apex of the anterior surface of the lens or a position nearby. The OCT unit 250 in this example further constructs an image from the data collected by the OCT scan in this example.

[0114] The tilt information generating unit 231 in this example first identifies the apex of the anterior surface of the crystalline lens as a feature point by analyzing the image constructed by the OCT unit 250. For example, the tilt information generating unit 231 applies segmentation to the image constructed by the OCT unit 250 to identify an image region corresponding to the anterior surface of the crystalline lens (anterior surface of the crystalline lens image). The tilt information generating unit 231 can approximate the identified anterior surface of the crystalline lens image with a differentiable figure (for example, a curve or a curved surface).

[0115] Next, the tilt information generating unit 231 identifies the apex of the anterior surface of the lens by analyzing the anterior surface image of the lens (or the lens image). For example, the tilt information generating unit 231 can identify the center position of the anterior surface image of the lens (for example, a point on the anterior surface image of the lens that is equidistant from both ends of the anterior surface image of the lens, or a point on the anterior surface image that is equidistant from both ends of the anterior surface image of the lens) and set it as the anterior surface apex of the lens. In another example, the tilt information generating unit 231 can identify the apex of the anterior surface of the lens based on the shape of the anterior surface image of the lens. In yet another example, the tilt information generating unit 231 can identify the apex of the anterior surface of the lens based on the morphology of the lens image. For example, the tilt information generating unit 231 can identify the position on the anterior surface image of the lens that is the farthest from the posterior surface image of the lens by referring to the thickness distribution of the lens image, and set this position as the anterior surface apex of the lens.

[0116] Furthermore, the tilt information generating unit 231 can obtain the tilt of the front surface of the lens at the identified vertex of the front surface of the lens, and use this tilt value or a value calculated from it as tilt information (tilt angle). The tilt of the front surface of the lens at the vertex of the front surface of the lens may be defined, for example, as the tilt of the tangent or the tilt of the tangent plane (for example, the tilt of the normal) of the front surface of the lens (a differentiable approximate figure) at the vertex of the front surface of the lens.

[0117] A specific example in which the feature point is the apex of the anterior surface of the lens will be described. See FIGS. 6A and 6B. First, the tilt information generation unit 231 applies segmentation to an image obtained by the ATA scan to identify the anterior surface of the lens 550 shown in FIG. 6A. The tilt information generation unit 231 then obtains a differentiable approximation of the anterior surface of the lens 550, and can use this approximation as the anterior surface of the lens 550. Next, the tilt information generation unit 231 analyzes the anterior surface of the lens 550 to identify the anterior surface of the lens vertex 560. Furthermore, the tilt information generation unit 231 obtains the inclination of a tangent 570 of the anterior surface of the lens 550 at the anterior surface of the lens vertex 560, and sets this inclination value (or a value calculated from it) as the inclination angle. The inclination angle thus generated is an example of inclination information indicating the inclination state of the anterior segment Ea when the ATA scan is applied.

[0118] An example in which the feature point is the corneal anterior apex will be described. In this example, the OCT unit 250 applies an OCT scan to a region including the corneal anterior apex (or a position nearby) of the subject's eye E. The OCT scan in this example may be, for example, a B-scan, a 3D scan, or a radial scan. The B-scan in this example may be, for example, the ATA scan described above. The region to which the 3D scan in this example is applied may be, for example, a volume whose center in the x and y directions is the corneal anterior apex or a position nearby. The radial scan (or cross scan) in this example may include, for example, multiple B-scans with different orientations that intersect at the corneal anterior apex or a position nearby. The OCT unit 250 in this example further constructs an image from the data collected by the OCT scan in this example.

[0119] The tilt information generating unit 231 in this example first identifies the vertex of the anterior corneal surface as a feature point by analyzing the image constructed by the OCT unit 250. For example, the tilt information generating unit 231 applies segmentation to the image constructed by the OCT unit 250 to identify an image region (anterior corneal surface image) corresponding to the anterior corneal surface. The tilt information generating unit 231 can approximate the identified anterior corneal surface image with a differentiable figure (for example, a curve or a curved surface).

[0120] Next, the tilt information generating unit 231 identifies the corneal apex by analyzing the front corneal surface image. For example, the tilt information generating unit 231 can identify the center position of the front corneal surface image (for example, a point on the front corneal surface image that is equidistant from both ends of the front corneal surface image, or a point on the front corneal surface image that is equidistant from both ends of the front corneal surface image along the front corneal surface image) and set it as the corneal apex. In another example, the tilt information generating unit 231 may identify the corneal apex based on the shape of the front corneal surface image.

[0121] Furthermore, the tilt information generating unit 231 can obtain the tilt of the front corneal surface image at the specified corneal apex, and use this tilt value or a value calculated from it as tilt information (tilt angle). The tilt of the front corneal surface image at the corneal apex may be defined, for example, as the tilt of the tangent or the tilt of the tangent plane (for example, the tilt of the normal) of the front corneal surface image (a differentiable approximate figure) at the corneal apex.

[0122] In this way, a series of processes that can be executed when the feature point is the vertex of the anterior surface of the lens can be executed in the same manner as when the feature point is the vertex of the anterior surface of the lens, for example.

[0123] An example will be described in which the feature points are points on the anterior iris surface. In this example, the OCT unit 250 applies an OCT scan to an area including at least a portion of the anterior iris surface of the subject's eye E. The OCT scan in this example may be, for example, any of a B-scan, a three-dimensional scan, and a radial scan. The OCT unit 250 in this example further constructs an image from the data collected by the OCT scan in this example.

[0124] The tilt information generating unit 231 of this example first identifies at least two points on the front surface of the iris as feature points by analyzing the image constructed by the OCT unit 250. For example, the tilt information generating unit 231 applies segmentation to the image constructed by the OCT unit 250 to identify the front surface of the iris. Next, the tilt information generating unit 231 identifies at least two points on the front surface of the iris as feature points. Subsequently, the tilt information generating unit 231 generates tilt information based on the at least two points on the front surface of the iris identified as feature points. The tilt information generating unit 231 of this example may be performed in the same manner as any one of the first to third examples of tilt information generation when the feature points are iridocorneal angles, but is not limited thereto.

[0125] A specific example in which the feature points are points on the front surface of the iris will be described with reference to FIGS. 7A and 7B. First, the gradient information generating unit 231 applies segmentation to an image obtained by ATA scanning to identify front surface iris images 581 and 582 shown in FIG. 7A. The front surface iris image 581 is located on the left edge of the image frame, and the front surface iris image 582 is located on the right edge of the image frame. Next, the gradient information generating unit 231 identifies one or more peaks in the front surface iris image 581 and one or more peaks in the front surface iris image 582. Next, the gradient information generating unit 231 identifies peak 581a located on the innermost side (closer to the crystalline lens) of the one or more peaks in the front surface iris image 581 and peak 582a located on the innermost side (closer to the crystalline lens) of the one or more peaks in the front surface iris image 582 (see FIG. 7B). Note that other peaks may also be identified. Furthermore, the tilt information generating unit 231 calculates the tilt of a line 590 connecting peaks 581a and 582a, and sets the value of this tilt (or a value calculated from it) as the tilt angle (see FIG. 7B). The tilt angle thus generated is an example of tilt information indicating the tilt state of the anterior segment Ea when the ATA scan is applied. Note that instead of calculating the peak of the iris front surface image, any point such as a valley of the iris front surface image, the innermost point (closer to the lens) of the iris front surface image, or the outermost point of the iris front surface image may be used as the feature point.

[0126] <Control unit 210> The control unit 210 shown in Fig. 4 controls the LCD 39 (fixation target presenting unit) based on the tilt information generated by the tilt information generating unit 231. In this embodiment, the control unit 210 controls the LCD 39 to move the fixation target. Specifically, the control unit 210 in this embodiment controls the LCD 39 to change the display position of the fixation target image. Some examples of the fixation target movement control in this embodiment will be described below.

[0127] A first example of fixation target movement control will be described. In this example, correspondence information 2121 shown in FIG. 4 is stored in a storage unit 212 created in advance. The correspondence information 2121 may be provided outside the control unit 210. For example, the correspondence information 2121 can be stored in a storage unit accessible by the control unit 210. The control unit 210 (main control unit 211) controls the fixation target presentation unit by referring to the correspondence information 2121 based on the tilt information generated by the tilt information generation unit 231.

[0128] The correspondence information 2121 is information indicating the correspondence between a parameter (tilt parameter) indicating the tilt state of the anterior segment in the image frame (image definition coordinate system) and a parameter (movement parameter) indicating the movement state of the fixation target. The main control unit 211 determines the corresponding movement parameter based on the tilt information and tilt parameter generated by the tilt information generation unit 231, for example, and controls the fixation target presentation unit based on the determined movement parameter.

[0129] The tilt parameter in this example is data comparable to the tilt information generated by the tilt information generating unit 231, and may be, for example, a tilt angle defined similarly to the tilt angle included in the tilt information (same reference direction), or a tilt angle defined by a reference direction (second reference direction) different from the reference direction (first reference direction) of the tilt angle included in the tilt information. On the other hand, the movement parameter in this example may be defined by address information (pixel position) on the display screen of the LCD 39, the movement amount of the fixation target (number of pixels, spatial dimensions, etc.), the control content for the LCD 39, etc.

[0130] The correspondence information 2121 may be created based on a preparatory measurement (preliminary measurement) using the ophthalmic device 1 or another ophthalmic device, may be created based on a computer simulation, may be created based on theoretical calculations, or may be created based on at least two of these three methods.

[0131] A typical example will be described. The tilt information in this example includes a tilt angle relative to a predetermined first reference direction in the image constructed by the OCT unit 250. The tilt parameter in this example includes a tilt angle relative to a predetermined second reference direction in the image frame. The first reference direction and the second reference direction may be the same, for example, the z direction or a direction perpendicular to it. When the first reference direction and the second reference direction are different from each other, both the first reference direction and the second reference direction can be expressed using the same coordinate system (e.g., an xyz coordinate system). For example, one of the first reference direction and the second reference direction is the z direction and the other is a direction perpendicular to the z direction. The movement parameter in this example includes the movement amount of the fixation target. Two examples of such correspondence information 2121 will be described below.

[0132] A first example of the correspondence information 2121 will be described. The tilt angle included in the tilt parameter in this example includes a predetermined unit angle relative to the second reference direction in the image frame. The unit angle is the smallest unit of the tilt angle calculated by the tilt information generating unit 231 and may be any value. The unit angle may be, for example, 1 degree, 3 degrees, 5 degrees, or 10 degrees. The movement amount included in the movement parameter in this example includes a movement amount (unit movement amount) corresponding to the unit angle included in the tilt parameter. The unit movement amount is the movement amount of the fixation target required to cancel the displacement amount of the subject's eye E (anterior segment Ea, a predetermined portion of the anterior segment Ea) when the tilt angle changes by the unit angle. In other words, it is the movement amount of the fixation target such that when the tilt angle changes by the unit angle, the relative position between the subject's eye E and the ophthalmologic apparatus 1 (optical system) remains substantially the same before and after the change. The unit movement amount is expressed, for example, as the number of pixels of the LCD 39 or information equivalent thereto, or as control content for the LCD 39. The correspondence information 2121 in this example may be generated based on, for example, a preliminary measurement using the ophthalmic apparatus 1 or another ophthalmic apparatus, a computer simulation, a theoretical calculation, or at least two of these three methods. In this example, the main control unit 211 executes, for example, a first calculation process of dividing the tilt angle calculated by the tilt information generating unit 231 by a unit angle, a second calculation process of multiplying the unit movement amount by the quotient value calculated in the first calculation process (or an integer approximating this quotient value), and a process of controlling the LCD 39 to move the fixation target by the product value calculated in the second calculation process (or an integer approximating this product value). The movement direction of the fixation target may be determined based on the tilt direction obtained by the tilt information generating unit 231 from the image. The movement direction of the fixation target is the direction in which the tilt angle decreases.

[0133] A second example of the correspondence information 2121 will be described. The correspondence information 2121 of this example includes information indicating the correspondence between a plurality of different tilt angles relative to the second reference direction in the image frame and a plurality of different movement amounts. The correspondence information 2121 of this example may be expressed in any form, such as a graph, a table, or a list representing the correspondence between the tilt angles and the movement amounts. The correspondence information 2121 of this example may be created based on, for example, a preliminary measurement using the ophthalmic apparatus 1 or another ophthalmic apparatus, a computer simulation, a theoretical calculation, or at least two of these three methods. In this example, the main control unit 211 executes, for example, a process of identifying an inclination angle in the correspondence information 2121 corresponding to the inclination angle calculated by the inclination information generating unit 231 (e.g., a process of identifying an inclination angle in the correspondence information 2121 that is equal to or closest to the calculated inclination angle), a process of determining a movement amount corresponding to the identified inclination angle from the correspondence information 2121, and a process of controlling the LCD 39 to move the fixation target by the determined movement amount. The movement direction of the fixation target is a direction in which the tilt angle decreases, and may be determined based on the tilt direction obtained by the tilt information generating section 231 from the image.

[0134] An example in which the tilt direction is taken into consideration will be described. In this example, the tilt information generation unit 231 calculates the tilt angle and tilt direction of the image relative to the first reference direction based on the image constructed by the OCT unit 250, and generates tilt information including both of these. The tilt parameters included in the correspondence information 2121 in this example include both the tilt angle and tilt direction of the image frame relative to the second reference direction. The movement parameters included in the correspondence information 2121 in this example include both the movement amount and movement direction of the fixation target. The correspondence information 2121 in this example may be created based on, for example, a preparatory measurement using the ophthalmic device 1 or another ophthalmic device, a computer simulation, a theoretical calculation, or at least two of these three methods. In this example, the main control unit 211, for example, by referring to the correspondence information 2121, determines the movement amount of the fixation target based on the tilt angle included in the tilt information generated by the tilt information generation unit 231, and determines the movement direction of the fixation target based on the tilt direction included in the tilt information. Furthermore, the main control unit 211 controls the LCD 39 so as to move the fixation target by the determined movement amount in the determined direction. This completes the description of the first example of fixation target movement control.

[0135] Next, a second example of fixation target movement control will be described. The first example of fixation target movement control described above operates to determine the amount and direction of movement of the fixation target from the detected tilt state, but this example (second example) operates to search for a suitable position of the fixation target while monitoring the tilt state. In this example, the correspondence information 2121 is not necessary. On the other hand, in this example, the movement direction and amount may be determined sequentially while referring to the correspondence information 2121.

[0136] The control unit 210 (main control unit 211) controls the LCD 39, the OCT unit 250, and the tilt information generating unit 231 in parallel. This parallel control may include, for example, one or more of simultaneous control, alternating control, and cyclic control.

[0137] In this example, the control of the LCD 39 is for moving a fixation target, and the manner in which the fixation target is moved by this control may be continuous, stepwise, or a combination of continuous and stepwise movement.

[0138] In this example, the OCT unit 250 is controlled to repeatedly apply OCT scans to the anterior segment Ea while sequentially constructing images. Any scan pattern may be used for this repetitive OCT scan, such as a B-scan. Such operation of the OCT unit 250 is called live OCT scanning or real-time OCT video capture.

[0139] The control of the tilt information generating unit 231 in this example is control for sequentially generating tilt information (for example, tilt angle and tilt direction) from images sequentially constructed by the OCT unit 250.

[0140] By combining these three controls, it is possible to perform OCT video capture and tilt information generation in real time while moving the fixation target (that is, while changing the line of sight of the subject's eye E).

[0141] In this combined control, the control unit 210 can feed back the generated tilt information to the fixation target movement control. That is, the control unit 210 can determine the movement direction of the fixation target based on any of the tilt information sequentially generated by the tilt information generating unit 231 from images sequentially constructed by the OCT unit 250, and control the LCD 39 to move the fixation target in the determined movement direction. The control unit 210 can also determine the movement amount of the fixation target based on any of the tilt information sequentially generated by the tilt information generating unit 231 from images sequentially constructed by the OCT unit 250, and control the LCD 39 to move the fixation target by the determined movement amount. Furthermore, by combining these, the control unit 210 can determine the movement direction and movement amount of the fixation target based on any of the tilt information sequentially generated by the tilt information generating unit 231 from images sequentially constructed by the OCT unit 250, and control the LCD 39 to move the fixation target by the determined movement amount in the determined movement direction. Note that the correspondence information 2121 can be referenced in such feedback control.

[0142] In this example, the control unit 210 determines whether the sequentially generated tilt information satisfies a predetermined condition (tilt state evaluation condition). Typically, the tilt information includes a tilt angle relative to a predetermined reference direction in the image (typically, a direction perpendicular to the z direction, i.e., the horizontal direction). In this case, the tilt state evaluation condition includes a condition related to the tilt angle. For example, the tilt state evaluation condition in this case may be that the tilt angle is smaller than a predetermined threshold. In this case, the control unit 210 determines whether the tilt angle sequentially generated by the tilt information generation unit 231 is equal to or smaller than the threshold, i.e., whether the tilt direction of the anterior segment is approximately aligned with the horizontal direction. This threshold is set in advance and has an arbitrary value. For example, the threshold can be changed depending on the application of the anterior segment OCT image. Typically, the threshold for anterior segment OCT images intended for analysis (measurement) may be set smaller than the threshold for anterior segment OCT images intended for observation.

[0143] Furthermore, the control unit 210 controls the LCD 39 to stop the movement of the fixation target in response to the generation of tilt information that satisfies the tilt state evaluation condition. This makes it possible to find the position of the fixation target where the tilt direction of the anterior segment of the eye is approximately aligned with the horizontal direction. In other words, it is possible to obtain an image in which there is almost no tilt of the anterior segment of the eye. This concludes the explanation of the second example of fixation target movement control.

[0144] <Operation of ophthalmic device> We will now explain some examples of the operation of the ophthalmologic apparatus 1. It is assumed that conventional preparatory processes such as inputting a patient ID and inserting the anterior segment OCT attachment 400 into the measurement arm have already been performed.

[0145] <First operation example> 8, a first example of the operation of the ophthalmic apparatus 1 will be described. This example is a basic operation example of the ophthalmic apparatus 1.

[0146] (S1: Start presenting the fixation target) The main controller 211 controls the LCD 39 to present a fixation target to the subject's eye E. The initial display position of the fixation target image may be, for example, the center position of the display screen of the LCD 39.

[0147] (S2: Start infrared photography of the anterior segment and live OCT) Next, the main controller 211 controls the fundus camera unit 2 to start infrared photography of the anterior segment Ea, and controls the OCT unit 250 to apply a live OCT scan to the anterior segment Ea. The live OCT scan in this example may be, for example, a repetitive ATA scan at a predetermined repetition rate.

[0148] (S3: Preparatory processing) Next, the ophthalmologic apparatus 1 performs predetermined preparatory processing by referring to the infrared observation image and / or the OCT image (B-scan image) of the anterior segment Ea, the acquisition of which has started in step S2. This preparatory processing may be, for example, alignment, focus adjustment, OCT polarization adjustment, etc.

[0149] (S4: Generate tilt information) After the preparatory processing is completed, the main controller 211 sends the OCT image obtained by the live OCT scan started in step S2 to the gradient information generator 231. This OCT image may be, for example, a single B-scan image constructed from data collected in a single ATA scan, or may be the most recent B-scan image. Alternatively, two or more OCT images may be provided to the gradient information generator 231.

[0150] The tilt information generating unit 231 generates tilt information that represents the tilt state of the anterior segment Ea depicted in the OCT image by analyzing the OCT image provided by the main controller 211. When two or more OCT images are provided, the tilt information generating unit 231 may, for example, create information that represents a time-series change in the tilt information (time-series tilt information), may statistically process two or more pieces of tilt information to generate a smaller number of pieces of tilt information (for example, one piece), may select one of the two or more pieces of tilt information, or may perform a process that combines two or more of these processes.

[0151] (S5: Control the fixation target presentation unit) Next, the control unit 210 controls the LCD 39 based on the tilt information generated in step S4.

[0152] (S6: Anterior segment OCT) After the fixation target control in step S5, the control unit 210 controls the OCT unit 250 to perform an OCT scan on the anterior segment Ea to obtain a (diagnostic) OCT image. The timing of this OCT scan is arbitrary. For example, the OCT scan may be performed immediately after the fixation target control in step S5, or may be performed after one or more steps have been performed after the fixation target control. Examples of steps performed after the fixation target control include checking the tilt state, evaluating the tilt state, displaying information, and accepting operations (instructions).

[0153] This allows the fixation target to be controlled in accordance with the tilt state of the anterior segment Ea depicted in the OCT image, and then an OCT scan can be applied to the anterior segment Ea to obtain an OCT image (for diagnosis). Therefore, an OCT scan can be applied to the anterior segment Ea after adjustments or corrections are made in accordance with the tilt state of the anterior segment Ea, making it possible to obtain an OCT image suitable for diagnosis, etc.

[0154] <Second operation example> A second example of the operation of the ophthalmologic apparatus 1 will be described with further reference to Fig. 9. This example is an example of the operation that can be performed when the first example of the fixation target movement control described above is applied. Correspondence information 2121 shown in Fig. 4 is stored in advance in the storage unit 212.

[0155] (S11~S14) Steps S11 to S14 may be executed in the same manner as steps S1 to S4 in the first operation example, respectively.

[0156] (S15: Determine the direction and amount of movement of the fixation target) The control unit 210 determines the movement direction and movement amount of the fixation target based on the tilt information generated in step S14 and with reference to the correspondence information 2121.

[0157] (S16: Move the fixation target) The control unit 210 moves the fixation target based on the movement direction and movement amount determined in step S15. For example, based on the movement direction and movement amount determined in step S15, the control unit 210 controls the LCD 39 so as to move the display position of the fixation target image in the movement direction by the movement amount.

[0158] The ophthalmologic device 1 may be configured to perform an anterior segment OCT scan (step S20) to obtain a (diagnostic) OCT image following step S16, but in this operation example, exemplary steps S17 to S19 described below are executed to confirm whether the position of the fixation target achieved in step S16 is suitable.

[0159] (S17: Generate tilt information) After the fixation target is moved in step S16, the control unit 210 sends a new OCT image (B-scan image) acquired by the OCT unit 250 performing the live OCT scan to the tilt information generation unit 231. The tilt information generation unit 231 analyzes this new OCT image to generate new tilt information representing the tilt state of the anterior segment Ea depicted in this new OCT image. This new tilt information includes at least the tilt angle.

[0160] (S18: Is the tilt angle below the threshold?) The control unit 210 compares the tilt angle included in the new tilt information generated in step S17 with a predetermined threshold value. If it is determined that the tilt angle is less than the threshold value (S18: Yes), the operation proceeds to step S19.

[0161] On the other hand, if it is determined that the tilt angle is equal to or greater than the threshold value (S18: No), the operation returns to step S 15. The processes of steps S15 to S18 are repeatedly executed, for example, until it is determined in step S18 that the tilt angle is less than the threshold value (S18: Yes).

[0162] In some examples, the control unit 210 can repeat the processes of steps S15 to S18 until a predetermined number of repetitions is reached, and can control the ophthalmologic apparatus 1 to stop operation or output an error (the fixation target cannot be presented in a suitable position) when the number of repetitions is reached. Also, in some examples, the control unit 210 can repeat the processes of steps S15 to S18 until a predetermined processing time is reached, and can control the ophthalmologic apparatus 1 to stop operation or output an error when the processing time is reached.

[0163] In this operation example, if it is determined that the tilt angle is equal to or greater than the threshold value (S18: No), the operation returns to step S15, but it may also be configured to return to step S14. In other words, if it is determined that the tilt angle is equal to or greater than the threshold value (S18: No), new tilt information may be generated from an OCT image (B-scan image) newly acquired by the OCT unit 250 performing a live OCT scan (S14), and the processes of steps S15 to S18 may be executed again based on this new tilt information.

[0164] (S19: "Shooting OK" is displayed) If it is determined in step S18 that the tilt angle is less than the threshold value (S18: Yes), the control unit 210 displays information indicating that the fixation target is presented in a suitable position and preparations for imaging (anterior segment OCT scan) are complete on the display unit 241. Recognizing the displayed information, the user can use the operation unit 242 to give instructions for imaging.

[0165] Note that, without displaying such information and performing an instruction operation, photography (anterior segment OCT scan) may be performed automatically in response to the determination in step S18 that the tilt angle is less than the threshold (S18: Yes) (auto-shoot function). Note that, even when the auto-shoot function is executed, information indicating that preparations for photography are complete may be displayed.

[0166] (S20: Anterior segment OCT) When an instruction to take a photograph is input (or when the conditions for activating the auto-shoot function are satisfied), the control unit 210 controls the OCT unit 250 to perform an OCT scan on the anterior segment Ea to obtain an OCT image (for diagnosis). Note that, as in the first operation example, the timing of performing this OCT scan may be arbitrary.

[0167] As a result, similar to the first operational example, the fixation target can be controlled according to the tilt state of the anterior eye segment Ea depicted in the OCT image, and then an OCT scan can be applied to the anterior eye segment Ea to obtain a (diagnostic) OCT image. Furthermore, according to this operational example, the amount and direction of movement can be automatically determined based on the tilt state of the anterior eye segment Ea depicted in the OCT image, and the fixation target can be moved. Therefore, the fixation target can be moved to a suitable position according to the tilt state of the anterior eye segment Ea, and then an OCT scan can be applied to the anterior eye segment Ea, making it possible to obtain an OCT image suitable for diagnosis, etc. Furthermore, according to this operational example, after moving the fixation target according to the tilt state of the anterior eye segment Ea, the tilt state after this movement can be reconfirmed. Furthermore, if the tilt state after movement is not satisfactory, the position of the fixation target can be adjusted again.

[0168] <Third operation example> A third example of the operation of the ophthalmologic apparatus 1 will be described with further reference to Fig. 10. This example is an example of the operation that can be performed when the second example of the fixation target movement control described above is applied. As described above, the correspondence information 2121 may or may not be referenced.

[0169] (S31~S33) Steps S31 to S33 may be executed in the same manner as steps S1 to S3 in the first operation example, respectively.

[0170] (S34: Start moving the fixation target and generating tilt information) In addition to the live OCT scan already started in step S32, the control unit 210 starts controlling the LCD 39 to move the fixation target and the tilt information generation unit 231 to generate tilt information, thereby starting parallel operations of the LCD 39, the OCT unit 250, and the tilt information generation unit 231.

[0171] (S35: Compare the slope information with the slope condition evaluation conditions) The control unit 210 compares the tilt information generated by the tilt information generation unit 231 in the parallel operation started in step S34 with a preset tilt state evaluation condition. For example, the control unit 210 compares the tilt angle generated by the tilt information generation unit 231 in the parallel operation started in step S34 with a predetermined threshold value.

[0172] (S36: Does the slope information satisfy the conditions?) In the comparison of step S35, control unit 210 determines whether the tilt information satisfies the tilt state evaluation condition. For example, control unit 210 determines whether the tilt angle is less than a threshold. If it is determined that the tilt information satisfies the tilt state evaluation condition (S36: Yes), the operation proceeds to step S37.

[0173] On the other hand, if it is determined that the tilt information does not satisfy the tilt state evaluation condition (S36: No), the operation returns to step S35. The parallel operation started in step S34 is still being executed. The control unit 210 compares the new tilt information generated by the tilt information generation unit 231 with the tilt state evaluation condition (S35). The processing of steps S35 to S36 is repeatedly executed, for example, until it is determined in step S36 that the tilt angle satisfies the tilt state evaluation condition (S36: Yes).

[0174] In some examples, the control unit 210 can repeat the processes of steps S35 to S36 until a predetermined number of repetitions is reached, and can control the ophthalmologic apparatus 1 to stop operation or output an error (the fixation target cannot be presented in a suitable position) when the number of repetitions is reached. Also, in some examples, the control unit 210 can repeat the processes of steps S35 to S36 until a predetermined processing time is reached, and can control the ophthalmologic apparatus 1 to stop operation or output an error when the processing time is reached.

[0175] (S37: Display "Shooting OK") If it is determined in step S36 that the tilt information satisfies the tilt state evaluation condition (S36: Yes), the control unit 210 causes the display unit 241 to display information indicating that the fixation target is presented in a suitable position and preparations for imaging (anterior segment OCT scan) are complete. The user, recognizing the displayed information, can use the operation unit 242 to give instructions for imaging.

[0176] Note that, without displaying such information and performing an instruction operation, photography (anterior segment OCT scan) may be performed automatically in response to the determination in step S36 that the tilt information satisfies the tilt state evaluation condition (S36: Yes) (auto-shoot function). Note that, even when the auto-shoot function is executed, information indicating that preparations for photography are complete may be displayed.

[0177] (S38: Anterior segment OCT) When an instruction to take a photograph is input (or when the conditions for activating the auto-shoot function are satisfied), the control unit 210 controls the OCT unit 250 to perform an OCT scan on the anterior segment Ea to obtain an OCT image (for diagnosis). Note that, as in the first operation example, the timing of performing this OCT scan may be arbitrary.

[0178] As a result, similar to the first operation example, the fixation target is controlled according to the tilt state of the anterior eye segment Ea depicted in the OCT image, and then an OCT scan is applied to the anterior eye segment Ea to acquire an OCT image (for diagnosis). Furthermore, according to this operation example, a suitable position for the fixation target can be searched for while referring to (monitoring) the tilt state of the anterior eye segment Ea depicted in the OCT image. Therefore, the fixation target can be moved to a suitable position according to the tilt state of the anterior eye segment Ea, and then an OCT scan can be applied to the anterior eye segment Ea, making it possible to acquire an OCT image suitable for diagnosis, etc.

[0179] <Combination of operation examples> It is possible to combine at least some of the steps in the second operation example with at least some of the steps in the third operation example. For example, the series of steps from steps S15 to S18 in the second operation example and the series of steps from steps S34 to S36 in the third operation example can be performed in any order (for example, alternately).

[0180] <Effects of ophthalmic devices> The effects of the ophthalmologic apparatus 1 will now be described. Fig. 11(A) shows a state in which a fixation target 610 arranged at a first position is presented to the subject's eye E. In an anterior segment OCT image (an image obtained by ATA scanning) 630 acquired at this time, the image of the anterior segment Ea is significantly tilted. Such an anterior segment OCT image is not suitable for anterior segment analysis, and it is not possible to accurately determine, for example, the inter-angular distance or the iridocorneal angle.

[0181] When such a situation occurs, the ophthalmic apparatus 1 can detect the tilt state of the image of the anterior segment in the anterior segment OCT image 630 and control the fixation target. By controlling the fixation target, for example, the fixation target presented to the subject's eye E can be changed from the fixation target 610 positioned at the first position shown in FIG. 11(A) to the fixation target 620 positioned at the second position shown in FIG. 11(B). This allows a transition from a state in which the anterior segment OCT image 630 shown in FIG. 11(A) is obtained to a state in which the anterior segment OCT image 640 shown in FIG. 11(B) is obtained. In other words, a transition can be made from a state in which the anterior segment OCT image 630 in which the image of the anterior segment Ea is tilted to a state in which the anterior segment OCT image 640 in which this tilt is almost eliminated is obtained. This enables accurate anterior segment analysis, such as iridocorneal angle analysis, to be performed. In this way, the ophthalmic apparatus 1 contributes to improving OCT anterior segment analysis.

[0182] <Other Aspects of the Ophthalmic Device> In the above-described embodiment, the ophthalmologic apparatus 1 automatically controls the fixation target in accordance with the imaging state (tilt state) of the anterior segment in the OCT image. On the other hand, in the embodiment described here, the user operates the fixation target, and the user's operation is assisted in accordance with the imaging state (tilt state) of the anterior segment in the OCT image.

[0183] The ophthalmic apparatus of this embodiment may have the same hardware configuration as the ophthalmic apparatus 1 described above. The software configuration may be the same as the software configuration of the ophthalmic apparatus 1 described above, except for the software configuration related to the characteristic operations of this embodiment. The ophthalmic apparatus of this embodiment has the configuration shown in FIGS. 1 to 3, and these drawings will be referenced as appropriate. In addition, in the description of the ophthalmic apparatus of this embodiment, the configuration shown in FIG. 12 will be referenced instead of the configuration shown in FIG. 4. Any of the details described for the ophthalmic apparatus 1 described above can be combined with the ophthalmic apparatus of this embodiment.

[0184] The LCD 39 (fixation target presenting unit) of the ophthalmologic apparatus of this embodiment presents a fixation target to the subject, similar to the LCD 39 of the ophthalmologic apparatus 1 described above.

[0185] The OCT section 250 of the ophthalmic apparatus of this embodiment, like the OCT section 250 of the above-described ophthalmic apparatus 1, applies OCT scanning to the anterior segment Ea of the subject's eye E to construct an image.

[0186] The tilt information generating unit 231 of the ophthalmic apparatus of this embodiment, similar to the tilt information generating unit 231 of the ophthalmic apparatus 1 described above, generates tilt information indicating the tilt state of the anterior segment Ea depicted in the image constructed by the OCT unit 250.

[0187] The operation unit 242 of the ophthalmologic apparatus of this embodiment is used for operating a fixation target by a user, and generates a signal (fixation target operation signal) in response to this operation.

[0188] The control unit 210 of the ophthalmologic apparatus of this embodiment controls the fixation target presenting unit based on a fixation target operation signal from the operation unit 242. This changes the position of the fixation target presented to the subject's eye E. In other words, the user can operate the position of the fixation target.

[0189] Furthermore, the control unit 210 of the ophthalmologic apparatus of this embodiment causes the display unit 241 (display means) to display information based on the tilt information generated by the tilt information generating unit 231. Here, the information displayed based on the tilt information includes information for assisting the user in manipulating the position of the fixation target.

[0190] The information based on the tilt information is, for example, sequentially created in parallel with a live OCT scan of the anterior segment Ea and displayed together with the live OCT image (real-time moving image) obtained by the live OCT scan. This allows the user to grasp the tilt state of the anterior segment Ea in the live OCT image in real time, and furthermore, can receive assistance in manipulating the position of the fixation target to correct the tilt state of the anterior segment Ea.

[0191] For example, the information displayed based on the tilt information may include one or more of the information described below: information indicating the tilt angle relative to a predetermined reference direction in the image of the anterior eye segment Ea acquired by the OCT unit 250 (tilt angle information); information indicating the amount of movement of the fixation target corresponding to this tilt angle (movement amount information); information indicating the tilt direction relative to a predetermined reference direction in the image of the anterior eye segment Ea acquired by the OCT unit 250 (tilt direction information); information indicating the movement direction of the fixation target corresponding to this tilt direction (movement direction information).

[0192] The tilt angle and tilt direction are acquired by the tilt information generating unit 231. The tilt angle information may be any display object (graphic, character string, image, etc.) indicating the tilt angle (angle magnitude) acquired by the tilt information generating unit 231. The tilt direction information may be any display object (graphic, character string, image, etc.) indicating the tilt direction (tilt direction) acquired by the tilt information generating unit 231.

[0193] The movement amount information is generated from the tilt angle acquired by the tilt information generating unit 231. Similarly, the movement direction information is generated from the tilt direction acquired by the tilt information generating unit 231. The process of generating other information (movement amount information, movement direction information, etc.) from the tilt information acquired by the tilt information generating unit 231 can be executed by, for example, referring to the correspondence information 2121 of the ophthalmologic apparatus 1 described above.

[0194] In this embodiment, the display unit 241 is an element of the ophthalmic device. However, in other embodiments, the display means does not need to be an element of the ophthalmic device, and may be, for example, a peripheral device of the ophthalmic device.

[0195] The ophthalmic device of this embodiment can provide the user with information to assist in manipulating the position of the fixation target according to the tilt state of the anterior segment Ea depicted in the OCT image. Therefore, the user can easily correct the tilt of the anterior segment Ea in the OCT image, making it easier to obtain OCT images suitable for diagnosis, etc. In this way, the ophthalmic device of this embodiment contributes to improving OCT anterior segment analysis.

[0196] <Method for controlling ophthalmic device> Some exemplary aspects provide a method for controlling an ophthalmic device. First and second aspects of the control method for an ophthalmic device will be described below. Any of the items described above for the ophthalmic device can be combined with the control method.

[0197] A first embodiment of a control method for an ophthalmic apparatus will be described. The ophthalmic apparatus in this embodiment includes a fixation target presenting unit, a scanning unit, and (at least one) processor. The fixation target presenting unit is configured to present a fixation target to the subject, and includes, for example, the LCD 39 described above. The scanning unit is configured to apply an OCT scan to the anterior segment of the subject's eye, and includes, for example, the optical system and mechanism of the OCT unit 250 described above (the group of elements forming the measurement arm in the fundus camera unit 2, and the OCT unit 100). In response to the control method of this embodiment, the processor executes the following three processes.

[0198] As a first process, the processor constructs an image based on the data collected by the scanning unit. The processor that executes the first process includes, for example, the image constructing unit 220 described above.

[0199] As the second process, the processor generates tilt information indicating the tilt state of the anterior segment Ea depicted in the constructed image. The processor that executes the second process includes, for example, the tilt information generating unit 231 described above.

[0200] As the third process, the processor controls the fixation target presenting unit based on the generated tilt information. The processor that executes the third process includes, for example, the control unit 210 described above.

[0201] According to the first aspect, the fixation target is controlled in accordance with the tilt state of the anterior eye segment Ea depicted in the OCT image, and then an OCT scan is applied to the anterior eye segment Ea to acquire an OCT image (for diagnosis). Therefore, an OCT scan can be applied to the anterior eye segment Ea after adjustment or correction according to the tilt state of the anterior eye segment Ea, and an OCT image suitable for diagnosis or the like can be acquired.

[0202] A second embodiment of the control method for an ophthalmic apparatus will now be described. The ophthalmic apparatus in this embodiment includes a fixation target presenting unit, a scanning unit, an operating unit, and (at least one) processor. The fixation target presenting unit is configured to present a fixation target to the subject, and includes, for example, the LCD 39 described above. The scanning unit is configured to apply an OCT scan to the anterior segment of the subject's eye, and includes, for example, the optical system and mechanisms of the OCT unit 250 described above (the group of elements forming the measurement arm in the fundus camera unit 2, and the OCT unit 100). The operating unit is configured to generate a signal in response to a user's operation, and includes, for example, the operating unit 242 described above. In response to the control method of this embodiment, the processor executes the following four processes.

[0203] As the first process, the processor constructs an image based on the data collected by the scanning unit. The processor that executes the first process includes, for example, the image constructing unit 220 described above.

[0204] As the second process, the processor generates tilt information indicating the tilt state of the anterior segment Ea depicted in the constructed image. The processor that executes the second process includes, for example, the tilt information generating unit 231 described above.

[0205] As a third process, the processor displays information based on the generated tilt information on a display means. The processor that executes the third process includes the above-mentioned control unit 210. The display means may be an element of the ophthalmic apparatus (such as the display unit 241) or a peripheral device of the ophthalmic apparatus.

[0206] As the fourth process, the processor controls the fixation target presentation unit based on a signal from the operation unit. The processor that executes the fourth process includes the control unit 210 described above.

[0207] For example, the user can refer to the information displayed in the third process and perform an operation to move the fixation target. In response to this operation, the ophthalmologic apparatus executes the fourth process to move the fixation target.

[0208] According to the second aspect, it is possible to provide the user with information to assist in manipulating the position of the fixation target in accordance with the tilt state of the anterior segment Ea depicted in the OCT image, thereby enabling the user to easily correct the tilt of the anterior segment Ea in the OCT image and facilitating the acquisition of OCT images suitable for diagnosis, etc.

[0209] <Programs and recording media> Some exemplary aspects provide a program that causes a computer (ophthalmic apparatus) to execute the above-described control method. For example, a program can be created that causes a computer to execute a first aspect of the ophthalmic apparatus control method. Also, a program can be created that causes a computer to execute a second aspect of the ophthalmic apparatus control method. These programs can be combined with any of the features described for the above-described ophthalmic apparatus.

[0210] It is possible to create a computer-readable non-transitory recording medium on which such a program is recorded. For example, it is possible to create a computer-readable non-transitory recording medium on which a program for causing a computer to execute a first aspect of the ophthalmic apparatus control method is recorded. It is also possible to create a computer-readable non-transitory recording medium on which a program for causing a computer to execute a second aspect of the ophthalmic apparatus control method is recorded. Any of the features described above for the ophthalmic apparatus can be combined with these recording media. The non-transitory recording medium may be in any form, such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory.

[0211] The configurations disclosed above are merely some examples of embodiments of the present invention. Those who intend to implement the present invention may make any modifications (omissions, substitutions, additions, etc.) within the scope of the gist of the present invention. [Explanation of symbols]

[0212] 1 Ophthalmology equipment 39 LCD 210 Control Unit 211 Main control unit 212 Storage section 2121 Compatibility Information 231 Slope information generation unit 240 User Interface 241 Display section 242 Operation section 250 OCT section

Claims

1. a fixation target presenting unit that presents a fixation target to a subject; an optical coherence tomography (OCT) unit that applies OCT scanning to an anterior segment of the subject's eye to construct an image; a tilt information generating unit that generates tilt information indicating a tilt state of the anterior eye segment depicted in the image; a control unit that controls the fixation target presentation unit based on the tilt information; Display and Including, the OCT unit performs a live OCT scan in which an image is sequentially constructed by repeatedly applying either a radial scan including a plurality of B-scans in different directions or a three-dimensional scan for a three-dimensional region to the anterior segment, The tilt information generating unit analyzing the image to identify three or more feature points of the angle of the subject's eye; determining a plane indicating the inclination of the angle based on the three or more feature points; A process of determining the inclination of the plane; generating the tilt information based on the tilt of the plane; repeatedly performed in parallel with the live OCT scan; The control unit sequentially generating information based on the gradient information repeatedly generated in parallel with the live OCT scan; displaying the sequentially generated information on the display unit together with a live OCT image obtained by the live OCT scan; Ophthalmology equipment.

2. the control unit displays, on the display unit together with the live OCT image, one or more pieces of information among tilt angle information indicating a tilt angle of the anterior eye segment with respect to a predetermined reference direction in the live OCT image, movement amount information indicating a movement amount of the fixation target corresponding to the tilt angle, tilt direction information indicating a tilt direction of the anterior eye segment with respect to the predetermined reference direction, and movement direction information indicating a movement direction of the fixation target corresponding to the tilt direction. The ophthalmic device of claim 1.

3. A method for controlling an ophthalmic apparatus including a fixation target presenting unit that presents a fixation target to a subject, a scanning unit that applies an optical coherence tomography (OCT) scan to an anterior segment of a subject's eye, at least one processor, and a display unit, the at least one processor; an image construction step of constructing an image based on the data collected by the scanning unit; a tilt information generating step of generating tilt information indicating a tilt state of the anterior eye segment depicted in the image; a control step of controlling the fixation target presentation unit based on the tilt information; a display step of displaying information based on the tilt information on the display unit; Execute the image construction step performs a live OCT scan in which the scan unit repeatedly applies either a radial scan including a plurality of B-scans oriented in different directions to the anterior segment or a three-dimensional scan to a three-dimensional region to the anterior segment, and constructs an image sequentially based on collected data; The gradient information generating step includes: analyzing the image to identify three or more feature points of the angle of the subject's eye; determining a plane indicating the inclination of the angle based on the three or more feature points; A process of determining the inclination of the plane; generating the tilt information based on the tilt of the plane; repeatedly performed in parallel with the live OCT scan; The display step includes: sequentially generating information based on the gradient information repeatedly generated in parallel with the live OCT scan; displaying the sequentially generated information on the display unit together with a live OCT image obtained by the live OCT scan; A method for controlling an ophthalmic device.

4. A program that causes a computer to execute the method of claim 3.

5. A computer-readable non-transitory recording medium on which the program of claim 4 is recorded.

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