Optical coherence tomography device, control method thereof, and program

Abstract

To provide a new technology to acquire an image of an object to be measured in excellent image quality when imaging the object to be measured with a wide angle.SOLUTION: An optical coherence tomography device includes an optical system and a control unit. The optical system is configured to change an optical condition and includes an optical scanner, and is configured to acquire optical coherence tomography data on an object to be measured by scanning the object to be measured with measurement light using the optical scanner. The control unit controls the optical scanner so as to scan the object to be measured with the measurement light along a high-speed scan axis with a reference position moving along a low speed scan axis as a reference. The control unit changes the optical condition in synchronization with a cycle of the low speed scan along the low speed scan axis.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an optical coherence tomography apparatus, a control method for an optical coherence tomography apparatus, and a program. [Background technology]

[0002] Optical Coherence Tomography (OCT) devices are known that use light beams from a laser light source or the like to form images that represent the surface and internal morphology of an object to be measured. Since OCT performed in OCT devices is not invasive to living organisms, it is expected that applications will be developed particularly in the medical and biological fields. For example, in the field of ophthalmology, devices that form images of the fundus and cornea have been put to practical use. Such devices that use OCT techniques (OCT devices) can be applied to the observation of various parts of the subject's eye. In addition, since high-resolution images can be obtained, they are used to diagnose various ophthalmic diseases.

[0003] When photographing a measured object at a wide angle, the optical conditions of the optical system that are optimal for photographing differ for each photographed part (scan area) depending on the cross-sectional shape of the measured object. As a result, the image quality around the target part may be insufficient, and it may become necessary to photograph the measured object again.

[0004] One solution to this problem is to widen the OCT imaging range in the depth direction (measurement range, depth range). However, the OCT imaging range in the depth direction is limited. In order to widen the imaging range in the depth direction, the cost of the detection system increases and the size of the optical system increases.

[0005] For example, Patent Document 1 discloses a method of performing a pre-scan and adjusting the optical path length of the reference light so that the entire tomographic image of the observed area is positioned at the optimal position within the B-scan image based on A-scan images at multiple positions in the scanning direction of the B-scan that have been acquired in advance. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2015-16151 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in Patent Document 1, a prescan must be performed before a main scan, which lengthens the imaging time (measurement time).When the object to be measured is a living eye, this increases the burden on the subject.

[0008] The present invention has been made in consideration of the above circumstances, and one of its objectives is to provide a new technique for acquiring an image of a measured object with good image quality when photographing the object at a wide angle. [Means for solving the problem]

[0009] One aspect of some embodiments is an optical coherence tomography device that includes an optical system configured to change optical conditions, includes an optical scanner, and is configured to acquire optical coherence tomography data of a measured object by scanning the measured object with a measurement light using the optical scanner; and a controller that controls the optical scanner to scan the measured object with the measurement light along a fast scan axis based on a reference position that moves along a slow scan axis, wherein the controller changes the optical conditions in synchronization with a period of the slow scan along the slow scan axis.

[0010] Another aspect of some embodiments is a method for controlling an optical coherence tomography device including an optical system configured to change optical conditions, including an optical scanner, and configured to acquire optical coherence tomography data of a measurement object by scanning the measurement object with a measurement light using the optical scanner. The method for controlling an optical coherence tomography device includes a control step of controlling the optical scanner to scan the measurement object with the measurement light along a fast scan axis based on a reference position moving along a slow scan axis, and an optical condition changing step of changing the optical conditions in synchronization with a period of the slow scan along the slow scan axis.

[0011] Yet another aspect of some embodiments is a program for causing a computer to execute each step of the above-described method for controlling an optical coherence tomography apparatus. Effect of the Invention

[0012] According to the embodiment of the present invention, it is possible to provide a new technique for acquiring an image of a measurement object with good image quality when photographing the measurement object at a wide angle. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic diagram illustrating an example of a configuration of an optical system of an ophthalmic apparatus according to a first embodiment. [Diagram 2] 1 is a schematic diagram illustrating an example of a configuration of an optical system of an ophthalmic apparatus according to a first embodiment. [Diagram 3] 1 is a schematic diagram illustrating an example of a configuration of an optical system of an ophthalmic apparatus according to a first embodiment. [Figure 4] 2 is a schematic diagram illustrating an example of the configuration of a processing system of the ophthalmic apparatus according to the first embodiment. FIG. [Diagram 5] 2 is a schematic diagram illustrating an example of the configuration of a processing system of the ophthalmic apparatus according to the first embodiment. FIG. [Figure 6] 3A to 3C are diagrams illustrating the operation of the ophthalmologic apparatus according to the first embodiment. [Figure 7] 3A to 3C are diagrams illustrating the operation of the ophthalmologic apparatus according to the first embodiment. [Figure 8] 3A to 3C are diagrams illustrating the operation of the ophthalmologic apparatus according to the first embodiment. [Figure 9] 3A to 3C are diagrams illustrating the operation of the ophthalmologic apparatus according to the first embodiment. [Figure 10] 3A to 3C are diagrams illustrating the operation of the ophthalmologic apparatus according to the first embodiment. [Figure 11] 3A to 3C are diagrams illustrating the operation of the ophthalmologic apparatus according to the first embodiment. [Figure 12A] 4 is a flow diagram of an example of the operation of the ophthalmologic apparatus according to the first embodiment. FIG. [Figure 12B] 4 is a flow diagram of an example of the operation of the ophthalmologic apparatus according to the first embodiment. FIG. [Figure 13A] 4 is a flow diagram of an example of the operation of the ophthalmologic apparatus according to the first embodiment. FIG. [Figure 13B] 4 is a flow diagram of an example of the operation of the ophthalmologic apparatus according to the first embodiment. FIG. [Figure 14] 10 is a schematic diagram illustrating an example of a configuration of an optical system of an ophthalmic apparatus according to a second embodiment. FIG. [Figure 15] 11 is a schematic diagram illustrating an example of the configuration of a processing system of an ophthalmic apparatus according to a second embodiment. FIG. [Figure 16] 10A to 10C are diagrams illustrating the operation of the ophthalmologic apparatus according to the first embodiment or the first modified example of the second embodiment. [Figure 17] 10A to 10C are diagrams illustrating the operation of the ophthalmologic apparatus according to the second modified example of the first embodiment or the second embodiment. [Figure 18] 11A to 11C are diagrams illustrating the operation of the ophthalmologic apparatus according to the third modified example of the first or second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] An example of an embodiment of an optical coherence tomography device, a control method for an optical coherence tomography device, and a program according to the present invention will be described in detail with reference to the drawings. Note that the contents of documents cited in this specification and any publicly known techniques can be used in the following embodiments.

[0015] An optical coherence tomography (OCT) device according to an embodiment includes an optical system configured to change optical conditions. The optical system includes an optical scanner, and is configured to acquire OCT data of the object by scanning the object with measurement light used in OCT using the optical scanner. The OCT device further includes a control unit that controls the optical scanner to scan the object with the measurement light by a single scan that combines a slow scan along a slow scan axis and a high-speed scan along a high-speed scan axis. Specifically, the control unit controls the optical scanner to scan the object with the measurement light along the high-speed scan axis based on a reference position of the high-speed scan moving along the low-speed scan axis. In addition, the control unit changes the optical conditions of the optical system in synchronization with the period of the low-speed scan along the low-speed scan axis during scanning (photographing, measurement).

[0016] When such an OCT device performs a first high-speed scan during a single scan that combines a low-speed scan and a high-speed scan, the optical conditions of the optical system can be changed in synchronization with the period of the low-speed scan based on OCT data obtained by a second high-speed scan that was performed before the first high-speed scan. In some embodiments, the optical conditions of the optical system are fixed during the high-speed scan.

[0017] In some embodiments, the control unit changes the optical conditions based on OCT data obtained by a high-speed scan (or A-scan) performed before the high-speed scan (or A-scan) in which the optical conditions of the optical system are changed during scanning, or on an OCT image formed based on the OCT data. Examples of high-speed scans performed before the high-speed scan in which the optical conditions of the optical system are changed include a high-speed scan performed immediately before a first high-speed scan in which the optical conditions of the optical system are changed, and a high-speed scan performed two or more times before the first high-speed scan. That is, the OCT device substantially estimates the cross-sectional structure of the object to be measured based on the OCT data or OCT image obtained by a high-speed scan performed in the past at a first high-speed scan position (area), and changes the optical conditions of the optical system in synchronization with the period of the low-speed scan based on the estimated cross-sectional structure. The OCT device performs a high-speed scan at a second high-speed scan position different from the first high-speed scan position, which is moved along the low-speed scan axis.

[0018] In some embodiments, a single scan is a combination of one slow scan (there may be one or more slow scans) and two or more fast scans performed between a predetermined scan start timing and a predetermined scan end timing. In some embodiments, a single scan is a single scan performed between a preset scan start position and a preset scan end position.

[0019] In some embodiments, the OCT device changes the optical conditions of the optical system for each of a plurality of scan regions set for the object to be measured in synchronization with the period of the slow scan along the slow scan axis during scanning. For example, the OCT device substantially estimates the cross-sectional structure of the object to be measured for each scan region based on OCT data or an OCT image obtained by a high-speed scan executed in the past, and changes the optical conditions of the optical system in synchronization with the period of the slow scan based on the estimated cross-sectional structure.

[0020] Examples of the optical conditions of the optical system include the amount of light of the measurement light used in OCT, the beam diameter, the focal position, the polarization component of the measurement light, the aberration correction component, the optical path length difference between the measurement light and the reference light, and the position of the optical system relative to the object to be measured.

[0021] The slow scan may be a scan defined by any one-dimensional or two-dimensional scan mode. The fast scan may be a scan defined by any one-dimensional or two-dimensional scan mode. Examples of such slow or fast scans include line scan, cross scan, circle scan, radial scan, concentric circle scan, multi-line cross scan, spiral scan, Lissajous scan, etc. Also, an example of a combination of a slow scan and a fast scan is a three-dimensional scan such as an ammonite scan. The ammonite scan is performed by combining a slow scan in which the slow scan axis is a spiral scan axis and a fast scan in which the fast scan axis is a circular scan axis.

[0022] This makes it possible to obtain an image of the object to be measured with good image quality when photographing the object at a wide angle without performing a pre-scan.

[0023] In some embodiments, the optical system includes one or more optical elements, and is configured to be able to change at least one of the focal position of the measurement light used in OCT, the polarization component of the measurement light, the aberration correction component, and the optical path length difference between the measurement light and the reference light by controlling the one or more optical elements.

[0024] In some embodiments, the optical system includes a mechanism for moving the optical system or one or more optical elements, and is configured to be able to change any of the focal position of the measurement light used in OCT, the polarization component of the measurement light, the aberration correction component, and the optical path length difference between the measurement light and the reference light by controlling the mechanism.

[0025] In some embodiments, the OCT device includes a movement mechanism that moves the optical system relative to the object to be measured, and is configured to be able to change the position of the optical system relative to the object to be measured by controlling the movement mechanism.

[0026] The focal position is changed by a focal position changing member as an optical element, for example, a lens movable along the optical axis, a liquid crystal lens, an Alvarez lens, etc.

[0027] The polarization components are changed by a polarization component changing member as an optical element. An example of the polarization components is a polarization controller. When splitting light from a light source into measurement light and reference light used in OCT, the polarization controller may change the polarization components of the light from the light source or the polarization components of the measurement light.

[0028] The aberration correction components are changed by an aberration correction device as an optical element, for example, a variable cross cylinder (hereinafter, referred to as VCC) lens, a liquid crystal lens, a wavefront aberration correction optical system including a deformable mirror, an Alvarez lens, etc.

[0029] The optical path length difference is changed by an optical path length changing member as an optical element or mechanism. An example of the optical path length changing member is a member that changes at least one of the optical path length of the measurement light and the optical path length of the reference light.

[0030] The position of the optical system with respect to the object to be measured is changed by a mechanism for changing at least one of the object to be measured and the optical system. An example of the mechanism is a moving mechanism for changing the relative position between the object to be measured and a holding member that holds the optical system.

[0031] In some embodiments, the optical system includes an interference optical system and an optical path length difference changing member. The interference optical system is configured to split light from a light source into measurement light and reference light, project the measurement light that has passed through a measurement optical path in which one or more optical elements are arranged onto an object to be measured, and detect interference light between return light from the object to be measured and the reference light that has passed through the reference optical path. The optical path length difference changing member changes the difference between the optical path length of the measurement light and the optical path length of the reference light. The control unit changes the optical conditions of the optical system by controlling at least one of the one or more optical elements and the optical path length difference changing member.

[0032] In some embodiments, the OCT device includes an image forming unit that forms an image of the object based on the OCT data, and an image quality evaluation value calculation unit that calculates an evaluation value of the image quality of the object, and a control unit that controls the one or more optical elements based on the calculated evaluation value.

[0033] For example, the control unit controls the one or more optical elements based on the calculated evaluation value so that the image of the object to be measured has a quality equal to or higher than a predetermined image quality level. Examples of image quality equal to or higher than the predetermined image quality level include image quality where the evaluation value of the image quality of the entire image is maximized, image quality where the evaluation value of the image quality of the entire image is equal to or higher than a predetermined threshold level, image quality where the statistical value of the evaluation value of the image quality of the multiple images calculated for each scan area is maximized, and image quality where the statistical value of the evaluation value of the image quality of the multiple images calculated for each scan area is equal to or higher than a predetermined threshold level. Here, examples of the statistical value include a maximum value, a minimum value, a median value, a mean value, a mode value, a range, a variance, a standard deviation, a weighted average value in which the weighting coefficient increases the closer to the target site (the optical axis of the optical system), or a value of a predetermined evaluation formula using any of the above statistical values.

[0034] In some embodiments, the OCT apparatus includes a moving mechanism that moves the optical system relative to the object to be measured, and the control unit changes the optical condition of the optical system by controlling the moving mechanism.

[0035] In some embodiments, the OCT device includes the image forming unit described above. The control unit controls the optical path length difference changing member based on the position of the object to be measured in the image.

[0036] In some embodiments, the scan region includes a central region including an optical axis of an optical system in the object to be measured, and one or more peripheral regions around the central region. For example, the one or more peripheral regions include one or more middle regions arranged outside the central region and surrounding the central region, and a peripheral region arranged outside an outermost middle region of the one or more middle regions and surrounding the outermost middle region.

[0037] This makes it possible to obtain an image of the object to be measured with good image quality even if the inclination of the cross section differs between the central region and one or more peripheral regions of the object to be measured.

[0038] The control method of the OCT device according to the embodiment is a method for controlling the OCT device according to the embodiment. The program according to the embodiment causes a computer to execute each step of the control method of the OCT device according to the embodiment. The recording medium (storage medium) according to the embodiment is any non-transitory recording medium in which the program according to the embodiment is recorded (stored) and which is readable by a computer. The recording medium may be an electronic medium using magnetism, light, magneto-optical, semiconductor, or the like. Typically, the recording medium is a magnetic tape, a magnetic disk, an optical disk, a magneto-optical disk, a flash memory, a solid state drive, or the like. In addition, it is also possible to transmit and receive this program via a network such as the Internet or a LAN.

[0039] Hereinafter, an OCT apparatus according to an embodiment will be described taking as an example an ophthalmic apparatus in which a measurement target is a living eye, however, the embodiment can also be applied to an OCT apparatus in which a measurement target is something other than a living eye.

[0040] The ophthalmologic apparatus according to the embodiment is capable of performing OCT on any part of the subject's eye, such as the fundus or anterior segment. In this specification, images acquired by OCT may be collectively referred to as OCT images. Furthermore, a measurement operation for forming an OCT image may be referred to as OCT measurement (main measurement, provisional measurement).

[0041] In the following, the embodiment will be described in detail with particular reference to a case where a swept-source type OCT technique is used in measurement or imaging using OCT. However, the configuration according to the embodiment can also be applied to an ophthalmic apparatus using other types of OCT (e.g., spectral domain type or time domain type).

[0042] In addition, in the following, we will explain the case where the evaluation value of image quality becomes higher as the image quality becomes better and the evaluation value becomes lower as the image quality becomes worse, but the embodiment is also applicable to cases where the evaluation value becomes lower as the image quality becomes better and the evaluation value becomes higher as the image quality becomes worse.

[0043] First Embodiment [composition] As shown in Figs. 1 to 3, an ophthalmologic apparatus 1 according to the first embodiment includes a fundus camera unit 2, an OCT unit 100, and an arithmetic and control unit 200. The fundus camera unit 2 has an optical system similar to that of a conventional fundus camera. The OCT unit 100 is provided with an optical system for acquiring an OCT image (e.g., a tomographic image) of the fundus (or anterior segment). The arithmetic and control unit 200 includes a computer that executes various arithmetic processes, control processes, and the like.

[0044] [Fundus camera unit 2] The fundus camera unit 2 shown in FIG. 1 is provided with an optical system for acquiring a two-dimensional image (fundus image) showing the surface morphology of the fundus Ef of the subject's eye E. The fundus image includes an observed image, a photographed image, and the like. The observed image is, for example, a monochrome moving image formed at a predetermined frame rate using near-infrared light. The photographed image may be, for example, a color image obtained by flashing visible light, or a monochrome still image using near-infrared light or visible light as illumination light. The fundus camera unit 2 may be configured to be capable of acquiring images other than these, for example, a fluorescein fluorescent image, an indocyanine green fluorescent image, or an autofluorescent image.

[0045] The fundus camera unit 2 is provided with a chin rest and a forehead rest for supporting the face of the subject. The fundus camera unit 2 is further provided with an illumination optical system 10 and a photographing optical system 30. The illumination optical system 10 irradiates the fundus Ef with illumination light. The photographing optical system 30 guides fundus reflection light of this illumination light to an imaging device (CCD image sensors (sometimes simply referred to as CCD) 35, 38). The photographing optical system 30 also guides measurement light from the OCT unit 100 to the fundus Ef, and also guides measurement light that has passed through the fundus Ef to the OCT unit 100.

[0046] The observation light source 11 of the illumination optical system 10 includes, for example, a halogen lamp. The light (observation illumination light) output from the observation light source 11 is reflected by a reflecting mirror 12 having a curved reflecting surface, passes through a condenser lens 13, and passes through a visible cut filter 14 to become near-infrared light. The observation illumination light is once focused near the imaging light source 15, reflected by a mirror 16, and passes through relay lenses 17 and 18, an aperture 19, and a relay lens 20. The observation illumination light is then reflected by the peripheral portion (the area around the hole) of the aperture mirror 21, passes through a dichroic mirror 48, and is refracted by the objective lens 22 to illuminate the fundus Ef. It is also possible to use an LED (Light Emitting Diode) as the observation light source.

[0047] The fundus reflected light of the observation illumination light is refracted by the objective lens 22, passes through the dichroic mirror 48, passes through a hole formed in the central region of the aperture mirror 21, passes through the dichroic mirror 55, passes through the focusing lens 31, and is reflected by the mirror 32. Furthermore, this fundus reflected light passes through the half mirror 33A, is reflected by the dichroic mirror 33, and is imaged on the light receiving surface of the CCD image sensor 35 by the condenser lens 34. The CCD image sensor 35 detects the fundus reflected light at a predetermined frame rate, for example. The display device 3 displays an image (observation image) based on the fundus reflected light detected by the CCD image sensor 35. When the focus of the photographing optical system 30 is adjusted to the anterior segment, an observation image of the anterior segment of the subject's eye E is displayed.

[0048] The photographing light source 15 includes, for example, a xenon lamp. Light (photographing illumination light) output from the photographing light source 15 is irradiated onto the fundus Ef through the same path as the observation illumination light. Fundus reflection light of the photographing illumination light is guided to the dichroic mirror 33 through the same path as the observation illumination light, passes through the dichroic mirror 33, is reflected by the mirror 36, and is imaged on the light receiving surface of the CCD image sensor 38 by the condenser lens 37. An image (photographed image) based on the fundus reflection light detected by the CCD image sensor 38 is displayed on the display device 3. The display device 3 that displays the observation image and the display device 3 that displays the photographed image may be the same or different. In addition, when the subject's eye E is illuminated with infrared light and similar photography is performed, an infrared photographed image is displayed. In addition, an LED can be used as the photographing light source.

[0049] The LCD (Liquid Crystal Display) 39 displays a fixation target and a visual target for visual acuity measurement. The fixation target is a visual target for fixing the subject's eye E, and is used during fundus photography, OCT measurement, and the like.

[0050] A part of the light output from the LCD 39 is reflected by the half mirror 33A, reflected by the mirror 32, passes through the focusing lens 31 and the dichroic mirror 55, and passes through the hole of the aperture mirror 21. The light that has passed through the hole is transmitted through the dichroic mirror 48, refracted by the objective lens 22, and projected onto the fundus Ef.

[0051] The fixation position of the subject's eye E can be changed by changing the display position of the fixation target on the screen of the LCD 39. The fixation position of the subject's eye E can be, for example, a position for acquiring an image centered on the macular part of the fundus Ef, a position for acquiring an image centered on the optic disc, a position for acquiring an image centered on the center of the fundus between the macular part and the optic disc, etc. Also, the display position of the fixation target can be arbitrarily changed.

[0052] Furthermore, the fundus camera unit 2 is provided with an alignment optical system 50 and a focus optical system 60, similar to conventional fundus cameras. The alignment optical system 50 generates a target (alignment target) for performing positioning (alignment) of the device optical system with respect to the subject's eye E. The focus optical system 60 generates a target (split target) for focusing on the fundus Ef.

[0053] Light (alignment light) output from an LED 51 of an alignment optical system 50 passes through apertures 52, 53 and a relay lens 54, is reflected by a dichroic mirror 55, and passes through a hole in the aperture mirror 21. The light that has passed through the hole is transmitted through a dichroic mirror 48, and is projected by the objective lens 22 onto the cornea of ​​the subject's eye E.

[0054] The corneal reflected light of the alignment light passes through the objective lens 22, the dichroic mirror 48, and the hole, a part of which passes through the dichroic mirror 55, passes through the focusing lens 31, is reflected by the mirror 32, and passes through the half mirror 33A. The corneal reflected light that passes through the half mirror 33A is reflected by the dichroic mirror 33 and is projected onto the light receiving surface of the CCD image sensor 35 by the condenser lens 34. The light receiving image (alignment target) by the CCD image sensor 35 is displayed on the display device 3 together with the observation image. The user performs the alignment by performing the same operations as in a conventional fundus camera. Alternatively, the arithmetic and control unit 200 may analyze the position of the alignment target and move the optical system to perform the alignment (auto-alignment function).

[0055] When performing focus adjustment, the reflecting surface of a reflecting rod 67 is obliquely disposed on the optical path of the illumination optical system 10. Light (focusing light) output from an LED 61 of the focusing optical system 60 passes through a relay lens 62, is split into two light beams by a split target plate 63, passes through a two-hole diaphragm 64, and is reflected by a mirror 65. The light reflected by the mirror 65 is once imaged on the reflecting surface of the reflecting rod 67 by a condenser lens 66 and is then reflected. Furthermore, the focusing light passes through a relay lens 20, is reflected by an apertured mirror 21, passes through a dichroic mirror 48, is refracted by an objective lens 22, and is projected onto the fundus Ef.

[0056] The fundus reflection light of the focusing light passes through the same path as the cornea reflection light of the alignment light and is detected by the CCD image sensor 35. The light image (split target) received by the CCD image sensor 35 is displayed on the display device 3 together with the observation image. The arithmetic and control unit 200 performs focusing by analyzing the position of the split target and moving the focusing lens 31 and the focus optical system 60 as in the conventional method (autofocus function). Alternatively, focusing may be performed manually while viewing the split target.

[0057] The dichroic mirror 48 branches the optical path for OCT measurement from the optical path for fundus imaging. The dichroic mirror 48 reflects light in the wavelength band used for OCT measurement and transmits light for fundus imaging. The optical path for OCT measurement includes, in order from the OCT unit 100 side, a collimator lens unit 40, an optical path length changer 41, an optical scanner 42, a collimator lens 43, a mirror 44, an OCT focusing lens 45, a field lens 46, and a VCC lens 47.

[0058] The optical path length changing unit 41 is configured to be movable in the direction of the arrow shown in Fig. 1, and changes the optical path length of the optical path for OCT measurement. This change in the optical path length is used for correcting the optical path length according to the axial length of the subject's eye E, adjusting the interference state, etc. The optical path length changing unit 41 is configured to include, for example, a corner cube and a mechanism for moving it.

[0059] The optical scanner 42 is disposed at a position optically conjugate with the pupil of the subject's eye (pupil conjugate position) or in the vicinity thereof. The optical scanner 42 changes the traveling direction of light (measurement light) passing through an optical path for OCT measurement. The optical scanner 42 is controlled by an arithmetic and control unit 200 (described later) and can deflect the measurement light one-dimensionally or two-dimensionally.

[0060] The optical scanner 42 includes, for example, a first galvanometer mirror, a second galvanometer mirror, and a mechanism for independently driving them. The first galvanometer mirror deflects the measurement light LS so as to scan the imaging site (fundus Ef or anterior segment) in a horizontal direction (x direction) perpendicular to the optical axis of the interference optical system. The second galvanometer mirror deflects the measurement light LS deflected by the first galvanometer mirror so as to scan the imaging site in a vertical direction (y direction) perpendicular to the optical axis of the interference optical system. This allows the imaging site to be scanned in any direction on the xy plane with the measurement light LS.

[0061] For example, it is possible to move the irradiation position of the measurement light along an arbitrary trajectory on the xy plane by simultaneously controlling the directions of the first galvanometer mirror and the second galvanometer mirror included in the optical scanner 42. This makes it possible to scan the imaging region according to a desired scan pattern.

[0062] The OCT focusing lens 45 is movable along the optical path of the measurement light LS (the optical axis of the interference optical system). The OCT focusing lens 45 is controlled by an arithmetic and control unit 200 (described later) and moves along the optical path of the measurement light LS.

[0063] In some embodiments, a liquid crystal lens or an Alvarez lens is provided instead of the OCT focusing lens 45. The liquid crystal lens or the Alvarez lens is controlled by the arithmetic and control unit 200 in the same manner as the OCT focusing lens 45.

[0064] The VCC lens 47 is disposed in the optical path of the measurement light, and changes at least one of the cylindrical power (cylindrical power) and the cylindrical axis angle (cylindrical axis angle). The VCC lens 47 has two cylindrical lenses (optical elements) disposed opposite each other, and is configured to change at least one of the cylindrical power and the cylindrical axis angle by changing at least one of the axial directions of the two cylindrical lenses. In the first embodiment, each of the two cylindrical lenses is configured to be independently rotatable so that the two axial directions are changed relatively. In addition, the two cylindrical lenses are configured to be integrally rotatable while maintaining the angle formed by the two axial directions.

[0065] The VCC lens 47 is disposed at a position optically conjugate with the pupil of the subject's eye (pupil conjugate position) or in the vicinity thereof. In the first embodiment, since the optical scanner 42 is disposed at a position optically conjugate with the pupil of the subject's eye, the VCC lens 47 is disposed in the vicinity of the position optically conjugate with the pupil of the subject's eye.

[0066] When the purpose is to correct the astigmatism power of the test eye E, even if the VCC lens 47 is positioned near the pupil conjugate position, it can be considered that the effect of the deviation of the position of the VCC lens 47 from the pupil conjugate position on the cylindrical power and cylindrical axis angle changed by the VCC lens 47 is small.

[0067] When the VCC lens 47 is controlled based on the optometry data (objective measurement values ​​or subjective test values) of the subject's eye E, the optometry data is mainly a measurement value at the fovea of ​​the subject's eye E. However, it may be considered that the deviation of the arrangement position of the VCC lens 47 from the pupil conjugate position has little effect on the cylindrical power and the cylindrical axis angle changed by the VCC lens 47. Therefore, even if the photographed part is a part other than the fovea, the VCC lens 47 may be arranged near the pupil conjugate position.

[0068] Such a VCC lens 47 includes cylindrical lenses 471, 472 (focal lengths f0, -f0) having the same power and different signs, as shown in FIG. 2, for example. The cylindrical lens 471 (VCC1) has a convex surface (positive power) and is provided rotatably in a rotation direction dr1 around the optical path of the measurement light LS (optical axis SO of the interference optical system). The cylindrical lens 472 (VCC2) has a concave surface (negative power) and is provided rotatably in a rotation direction dr2 around the optical axis SO. The cylindrical lenses 471, 472 are driven by a driving device such as a pulse motor and are rotated independently around the optical axis SO. When the cylindrical lenses 471, 472 are rotated in opposite directions, the cylindrical power is changed, and when they are rotated together in the same direction, the cylindrical axis angle is changed.

[0069] For example, any cylindrical power can be generated by rotating the cylindrical lenses 471, 472 in opposite directions from a state in which the cylindrical axis angles of the cylindrical lenses 471, 472 are inclined at a predetermined angle (for example, 45 degrees) with respect to the optical axis SO. Also, any cylindrical axis angle can be generated by integrally rotating the cylindrical lenses 471, 472 in the same direction.

[0070] [OCT Unit 100] An example of the configuration of the OCT unit 100 will be described with reference to FIG. 3. The OCT unit 100 is provided with an optical system for acquiring an OCT image of the fundus Ef. This optical system has the same configuration as a conventional swept-source type OCT device. That is, this optical system is an interference optical system that splits light from a wavelength scanning (wavelength swept) light source into measurement light and reference light, causes the measurement light that has passed through the fundus Ef to interfere with the reference light that has passed through a reference light path to generate interference light, and detects this interference light. The detection result (detection signal) of the interference light in the interference optical system is a signal indicating the spectrum of the interference light, and is sent to the arithmetic and control unit 200.

[0071] The light source unit 101 includes a wavelength scanning type (wavelength sweep type) light source capable of scanning (sweeping) the wavelength of emitted light, similar to a general swept source type OCT device. The light source unit 101 changes the output wavelength over time in the near-infrared wavelength band that is invisible to the human eye.

[0072] Light L0 output from light source unit 101 is guided by optical fiber 102 to polarization controller 103, where its polarization state is adjusted. The polarization controller 103 adjusts the polarization state of light L0 guided through optical fiber 102, for example, by applying stress from the outside to looped optical fiber 102.

[0073] The light L0, whose polarization state has been adjusted by the polarization controller 103, is guided by an optical fiber 104 to a fiber coupler 105, where it is split into a measurement light LS and a reference light LR.

[0074] The reference light LR is guided by an optical fiber 110 to a collimator 111 to become a parallel light beam. The parallel light beam of the reference light LR passes through an optical path length correction member 112 and a dispersion compensation member 113 and is guided to a corner cube 114. The optical path length correction member 112 acts as a delay means for matching the optical path lengths (optical distances) of the reference light LR and the measurement light LS. The dispersion compensation member 113 acts as a dispersion compensation means for matching the dispersion characteristics of the reference light LR and the measurement light LS.

[0075] The corner cube 114 reverses the traveling direction of the reference light LR, which has been collimated by the collimator 111. The optical path of the reference light LR incident on the corner cube 114 is parallel to the optical path of the reference light LR emerging from the corner cube 114. The corner cube 114 is movable in a direction along the incident optical path and emerging optical path of the reference light LR. This movement changes the length of the optical path of the reference light LR (reference optical path).

[0076] The reference light LR that has passed through the corner cube 114 passes through a dispersion compensation member 113 and an optical path length correction member 112, is converted from a parallel light beam to a convergent light 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 the polarization state of the reference light LR is adjusted.

[0077] The polarization controller 118 has, for example, the same configuration as the polarization controller 103. The reference light LR whose polarization state has been adjusted by the polarization controller 118 is guided to an attenuator 120 by an optical fiber 119, and the light amount is adjusted under the control of the arithmetic and control unit 200. The reference light LR whose light amount has been adjusted by the attenuator 120 is guided to a fiber coupler 122 by an optical fiber 121.

[0078] The measurement light LS generated by the fiber coupler 105 is guided by the optical fiber 127 and collimated by the collimating lens unit 40. The measurement light LS collimated passes through the optical path length changer 41, the optical scanner 42, the collimating lens 43, the mirror 44, the OCT focusing lens 45, the field lens 46, and the VCC lens 47 to reach the dichroic mirror 48. The measurement light LS is then reflected by the dichroic mirror 48, refracted by the objective lens 22, and irradiated onto the fundus Ef. The measurement light LS is scattered (including reflected) at various depth positions of the fundus Ef. The backscattered light of the measurement light LS by the fundus Ef travels in the opposite direction along the same path as the outward path and is guided to the fiber coupler 105, and reaches the fiber coupler 122 via the optical fiber 128.

[0079] The fiber coupler 122 generates interference light by combining (causing interference between) 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 generates a pair of interference light LC by splitting the interference light between the measurement light LS and the reference light LR at a predetermined splitting ratio (for example, 50:50). The pair of interference light LC output from the fiber coupler 122 is guided to a detector 125 by optical fibers 123 and 124, respectively.

[0080] The detector 125 is, for example, a balanced photodiode having a pair of photodetectors that respectively detect a pair of interference light LC and outputting the difference between the detection results by these. The detector 125 sends the detection results (detection signals) to the arithmetic and control unit 200. The arithmetic and control unit 200 forms a tomographic image as an OCT image by performing a Fourier transform or the like on the spectral distribution based on the detection results obtained by the detector 125, for example, for each series of wavelength scans (for each A-line). The arithmetic and control unit 200 causes the display device 3 to display the formed image.

[0081] In the first embodiment, a Michelson type interferometer is used, but any type of interferometer, such as a Mach-Zehnder type, can be appropriately used. In this embodiment, the interference optical system may include the collimator lens unit 40, the optical path length changer 41, the optical scanner 42, the collimator lens 43, the mirror 44, the OCT focusing lens 45, the field lens 46, and the VCC lens 47 shown in FIG. 1 in addition to the configuration shown in FIG. 3. This interference optical system is an example of an "interference optical system" according to the embodiment. The VCC lens 47 (and the VCC driver 47A described later) is an example of an "aberration correction device (aberration correction member, astigmatism correction optical member)" according to the embodiment. The OCT focusing lens 45 (and the OCT focusing driver 45A described later) is an example of a "focus position changer" according to the embodiment. At least one of the optical path length changer 41 and the corner cube 114 (and the reference driver 114A described later) is an example of an "optical path length changer" according to the embodiment. At least one of the polarization controllers 103 and 118 is an example of a "polarization state changing member" according to an embodiment.

[0082] [Arithmetic and control unit 200] The configuration of the arithmetic and control unit 200 will be described.

[0083] Figures 4 and 5 show block diagrams of a configuration example of the processing system (control system) of the ophthalmic apparatus 1 according to the first embodiment. Figure 5 is a functional block diagram of a configuration example of the analysis unit 232 in Figure 4. In Figure 4, the same parts as those in Figures 1 to 3 are given the same reference numerals, and the description will be omitted as appropriate.

[0084] The arithmetic and control unit 200 forms an OCT image of the fundus Ef (or the anterior segment) by analyzing the detection signal input from the detector 125. The arithmetic and control process for this purpose is similar to that of a conventional swept-source type OCT device.

[0085] 4, the arithmetic and control unit 200 includes a control unit 210, and controls each part of the fundus camera unit 2, the display device 3, and the OCT unit 100. For example, the arithmetic and control unit 200 forms an OCT image of the fundus Ef, and causes the display device 3 to display the formed OCT image.

[0086] The control of the fundus camera unit 2 includes operation control of the observation light source 11, the imaging light source 15 and the LEDs 51, 61, operation control of the CCD image sensors 35, 38, operation control of the LCD 39, movement control of the focusing lens 31, movement control of the OCT focusing lens 45, movement control of the reflecting rod 67, operation control of the alignment optical system 50, movement control of the focus optical system 60, movement control of the optical path length changing section 41, drive control of the VCC lens 47, and operation control of the optical scanner 42.

[0087] The control of the OCT unit 100 includes operation control of the light source unit 101 , movement control of the corner cube 114 , operation control of the detector 125 , operation control of the attenuator 120 , operation control of the polarization controllers 103 and 118 , and the like.

[0088] The arithmetic control unit 200 includes, for example, a processor, a random access memory (RAM), a read only memory (ROM), a hard disk drive, a communication interface, and the like, similar to a conventional computer. A computer program for controlling the ophthalmic apparatus 1 is stored in a storage device such as a hard disk drive. The arithmetic control unit 200 may include various circuit boards, for example, a circuit board for forming an OCT image. The arithmetic control unit 200 may also include operation devices (input devices) such as a keyboard and a mouse, and a display device such as an LCD.

[0089] The processor includes circuits such as 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)), etc. The processor realizes the functions of the embodiment by, for example, reading and executing a program stored in a memory circuit or a storage device. The memory circuit or storage device may be included in the processor. Also, the memory circuit or storage device may be provided outside the processor. In some embodiments, the functions of the arithmetic control unit 200 are realized by one or more processors.

[0090] The fundus camera unit 2, the display device 3, the OCT unit 100 and the arithmetic and control unit 200 may be configured integrally (i.e., within a single housing) or may be configured separately in two or more housings.

[0091] The control unit 210 includes a main control unit 211 and a storage unit 212 .

[0092] (Main control unit 211) The main controller 211 performs various controls by outputting control signals to each part of the above-mentioned ophthalmologic apparatus 1. In particular, the main controller 211 controls the CCD image sensors 35, 38, LCD 39, focusing driver 31A, optical path length changer 41, optical scanner 42, OCT focusing driver 45A, and VCC driver 47A for the fundus camera unit 2. Furthermore, the main controller 211 controls the light source unit 101, reference driver 114A, polarization controllers 103, 118, attenuator 120, and detector 125 for the OCT unit 100.

[0093] The main controller 211 controls the exposure time (charge accumulation time), sensitivity, frame rate, etc. of the CCD image sensor 35 or the CCD image sensor 38. In some embodiments, the main controller 211 controls the CCD image sensor 35 or the CCD image sensor 38 so as to obtain an image of a desired image quality.

[0094] The main controller 211 controls the display of fixation targets and visual acuity measurement targets on the LCD 39. This allows the visual target presented to the subject's eye E to be switched or the type of visual target to be changed. In addition, by changing the display position of the visual target on the LCD 39, it is possible to change the visual target presentation position with respect to the subject's eye E.

[0095] The focusing driver 31A moves the focusing lens 31 in the optical axis direction. The main controller 211 controls the focusing driver 31A so that the focusing lens 31 is positioned at a desired focusing position. This causes the focusing position of the photographing optical system 30 to be changed.

[0096] For example, the main controller 211 analyzes the position of the split target in the received light image (split target) obtained by the CCD image sensor 35, and controls the focusing driver 31A and the focus optical system 60. Alternatively, for example, the main controller 211 controls the focusing driver 31A and the focus optical system 60 in response to an operation performed by a user on an operation unit 240B described later, while displaying a live image of the subject's eye E on a display unit 240A described later.

[0097] The main controller 211 changes the optical path length of the measurement light LS by controlling the optical path length changer 41. This changes the difference between the optical path length of the measurement light LS and the optical path length of the reference light LR.

[0098] For example, the main control unit 211 analyzes the detection result of the interference light LC obtained by OCT measurement (or an OCT image formed based on the detection result), and controls the optical path length changing unit 41 so that the measurement site is at the desired depth position.

[0099] The main controller 211 controls the optical scanner 42. The main controller 211 controls the optical scanner 42 so as to deflect the measurement light LS according to a deflection pattern corresponding to a preset scan mode.

[0100] Examples of such scanning modes include line scan, cross scan, circle scan, radial scan, concentric circle scan, multi-line cross scan, spiral scan, Lissajous scan, and 3D scan (including a combination of slow and fast scans).

[0101] Line scan is a scan mode in which the measurement light LS is deflected so that the movement locus of the irradiation position of the measurement light LS on the imaging site (measurement site) is linear. The line direction of the movement locus can be changed (rotated) around the optical axis on the xy plane.

[0102] For example, line scanning includes horizontal scanning and vertical scanning. Horizontal scanning is a scanning mode in which the measurement light LS is deflected so that the movement trajectory of the irradiation position of the measurement light LS is in the horizontal direction (x direction). Horizontal scanning also includes a mode in which the measurement light LS is scanned along a plurality of horizontally extending scan lines arranged in the vertical direction (y direction). In this mode, the interval between the scan lines can be set arbitrarily. Also, by making the interval between adjacent scan lines sufficiently narrow, a three-dimensional image can be formed (three-dimensional scanning). The same applies to vertical scanning.

[0103] The cross scan is a scan mode in which the measurement light LS is deflected so that the movement trajectory of the irradiation position of the measurement light LS in the imaging region (measurement region) is cross-shaped. For example, the cross scan can be performed by performing two line scans whose line directions cross each other. The angle at which the two line scans cross is changeable. In some embodiments, the scan lengths in the B scan direction of the two line scans are the same. In some embodiments, the scan lengths in the B scan direction of the two line scans are different.

[0104] The circle scan is a scan mode in which the measurement light LS is deflected so that the movement locus of the irradiation position of the measurement light LS in the imaging region (measurement region) is, for example, circular around the optical axis SO. For example, in the circle scan, the measurement light LS is deflected so that the movement locus is a perfect circle, an ellipse, or an arc (part of a circumference).

[0105] Radial scanning is a scanning mode in which the measurement light LS is deflected so that the movement locus of the irradiation position of the measurement light LS at the imaging site (measurement site) is radial, for example, from the optical axis SO. In radial scanning, the irradiation position of the measurement light LS is moved along a radial locus consisting of a plurality of straight line loci arranged at a predetermined angle. The above-mentioned cross scanning is one aspect of radial scanning.

[0106] For example, in radial scanning, two or more line scans are performed with different B-scan directions. In some embodiments, the scan lengths in the B-scan direction of the two or more line scans are the same. In some embodiments, the scan length in the B-scan direction of at least one of the two or more line scans is different from the other scan lengths.

[0107] Concentric scanning is a scanning mode in which the measurement light LS is deflected so that the movement locus of the irradiation position of the measurement light LS in the imaging region (measurement region) is, for example, concentric around the optical axis SO. For example, in concentric scanning, the measurement light LS is deflected so that the movement locus of each circle is a perfect circle, an ellipse, or an arc (part of a circumference). In some embodiments, concentric scanning is performed by combining multiple circle scans with different diameters. Circle scanning is one aspect of concentric scanning.

[0108] A multi-line cross scan is a scan pattern in which a group of parallel horizontal scan lines (e.g., five lines) and a group of parallel vertical scan lines (e.g., five lines) are arranged so that they intersect at right angles near the center positions of both scan line groups.

[0109] For example, in each scan line group in the multi-line cross scan, two or more line scans are performed. In some embodiments, the scan length in the B-scan direction of the two or more line scans is the same. In some embodiments, the scan length in the B-scan direction of at least one of the two or more line scans is different from the other scan lengths.

[0110] Spiral scanning is a scanning mode in which the measurement light LS is deflected so that the movement locus of the irradiation position of the measurement light LS at the imaging site (measurement site) is, for example, spiral around the optical axis SO. In spiral scanning, the irradiation position of the measurement light LS is moved along a spiral locus while gradually decreasing (or increasing) the radius of rotation.

[0111] The Lissajous scan is a scan mode in which the measurement light LS is deflected so that the movement trajectory of the irradiation position of the measurement light LS in the imaging region (measurement region) follows a Lissajous curve. The Lissajous scan is disclosed in, for example, JP 2018-68578 A.

[0112] An example of a scan that combines a low-speed scan and a high-speed scan is an ammonite scan (3D scan). The ammonite scan is a scan mode in which the scan reference position (scan center position) of a circle scan as a high-speed scan is moved along the scan pattern of a spiral scan as a low-speed scan. That is, while moving the scan center position along the spiral scan pattern, circle scans are sequentially performed around each scan center position. As described above, the low-speed scan may be a scan defined by any one-dimensional or two-dimensional scan mode, and the high-speed scan may be a scan defined by any one-dimensional or two-dimensional scan mode. Examples of low-speed or high-speed scans include a line scan, a cross scan, a circle scan, a radial scan, a concentric circle scan, a multi-line cross scan, a spiral scan, and a Lissajous scan.

[0113] By scanning the imaging area with the measurement light LS according to a deflection pattern corresponding to the above-mentioned scan mode, a tomographic image can be obtained as an OCT image in a plane defined by the direction along the scan line (scan trajectory) and the fundus depth direction (z direction).

[0114] The OCT focusing driver 45A moves the OCT focusing lens 45 along the optical axis of the measurement light LS. The main controller 211 controls the OCT focusing driver 45A so that the OCT focusing lens 45 is positioned at a desired focusing position. This changes the focusing position of the measurement light LS. The focusing position of the measurement light LS corresponds to the depth position (z position) of the beam waist of the measurement light LS.

[0115] For example, the main control unit 211 controls the OCT focusing drive unit 45A based on the signal-to-noise ratio of the detection result of the interference light LC obtained by OCT measurement, or an evaluation value (including a statistical value of the evaluation value) corresponding to the image quality of the OCT image formed based on the detection result.

[0116] When a liquid crystal lens or an Alvarez lens is provided instead of the OCT focusing lens 45, the main control unit 211 can control the liquid crystal lens or the Alvarez lens in the same manner as it controls the OCT focusing drive unit 45A.

[0117] The VCC driver 47A rotates the cylindrical lenses 471 and 472 independently of each other about the optical axis of the measurement light LS, thereby changing at least one of the cylindrical power and the cylindrical axis angle.

[0118] For example, the main controller 211 controls the VCC driver 47A based on the signal-to-noise ratio of the detection result of the interference light LC obtained by OCT measurement, or an evaluation value (including a statistical value of the evaluation value) corresponding to the image quality of the OCT image formed based on the detection result. In some embodiments, the main controller 211 controls the VCC driver 47A based on the signal-to-noise ratio of the detection result of the interference light LC obtained by deflecting the measurement light LS according to a deflection pattern corresponding to a circle scan, or an evaluation value (including a statistical value of the evaluation value) corresponding to the image quality of the OCT image formed based on the detection result.

[0119] When a liquid crystal lens, a deformable mirror, or an Alvarez lens is provided instead of the VCC lens 47, the main control unit 211 can control the liquid crystal lens, the deformable mirror, or the Alvarez lens in the same manner as the VCC driving unit 47A.

[0120] The main control unit 211 controls the light source unit 101. The control of the light source unit 101 includes switching the light source on and off, controlling the intensity of the emitted light, changing the central frequency of the emitted light, changing the sweep speed of the emitted light, changing the sweep frequency, changing the sweep wavelength range, and the like.

[0121] The reference driver 114A moves the corner cube 114 provided in the optical path of the reference light along this optical path, thereby changing the difference between the optical path length of the measurement light LS and the optical path length of the reference light LR.

[0122] For example, the main controller 211 analyzes the detection result of the interference light LC obtained by the OCT measurement (or an OCT image formed based on the detection result), and controls the reference driver 114A so that the measurement site is at a desired depth position. In some embodiments, only one of the optical path length changer 41 and the reference driver 114A is provided.

[0123] The main control unit 211 controls the polarization controllers 103, 118. For example, the main control unit 211 controls the polarization controllers 103, 118 based on the signal-to-noise ratio of the detection result of the interference light LC obtained by OCT measurement, or an evaluation value (including a statistical value of the evaluation value) corresponding to the image quality of an OCT image formed based on the detection result.

[0124] The main controller 211 controls the attenuator 120. For example, the main controller 211 controls the attenuator 120 based on the signal-to-noise ratio of the detection result of the interference light LC obtained by OCT measurement, or an evaluation value (including a statistical value of the evaluation value) corresponding to the image quality of an OCT image formed based on the detection result.

[0125] The main control unit 211 controls the detector 125. The control of the detector 125 includes control of the exposure time (charge accumulation time), sensitivity, frame rate, and the like.

[0126] The moving mechanism 150 moves the fundus camera unit 2 (OCT unit 100) three-dimensionally relative to the subject's eye E. For example, the main controller 211 can control the moving mechanism 150 to move the optical system provided in the fundus camera unit 2 three-dimensionally. This control is used for alignment and tracking. Tracking refers to moving the device optical system in accordance with the movement of the subject's eye E. When tracking is performed, alignment and focusing are performed in advance. Tracking is a function that maintains a suitable positional relationship with good alignment and focus by moving the device optical system in real time in accordance with the position and orientation of the subject's eye E based on an image obtained by capturing a video of the subject's eye E.

[0127] In some embodiments, the main controller 211 corrects the position of the scan range for OCT imaging in real time based on tracking information obtained by tracking control (tracking information obtained by tracking the optical system (interference optical system) with respect to the movement of the subject's eye E). The main controller 211 can control the optical scanner 42 to scan the corrected scan range with the measurement light LS.

[0128] In some embodiments, the main controller 211 changes the optical conditions (photographing conditions, measurement conditions) of the optical system by controlling the optical system constituting the ophthalmic apparatus 1 based on setting information previously stored in the storage unit 212. In this case, the main controller 211 can generate the setting information in advance based on a detection result of the interference light LC acquired in a provisional measurement (provisional photography) performed before the main measurement (main photography) or an OCT image formed from the detection result. The main controller 211 may also generate the setting information in advance based on eyeball shape information (or eyeball aberration information) statistically obtained from a plurality of different pieces of eyeball information.

[0129] The main controller 211, as a display controller, causes the display device 3 (or the display device 240A described later) to display various information. The information displayed on the display device 3 includes the imaging results (observation image, OCT image (image of the subject's eye formed based on the detection result of interference light LC obtained by scanning with the measurement light LS), measurement results (measurement values), evaluation values ​​of image quality described later, statistics calculated based on the evaluation values, evaluation index information corresponding to the evaluation values, and the like. The main controller 211 is capable of causing the display device 3 to display the evaluation values, statistics, or evaluation index information of the image quality of the OCT image in association with the OCT image.

[0130] Furthermore, the main control unit 211 performs processing for writing data to the storage unit 212 and processing for reading data from the storage unit 212 .

[0131] (Storage unit 212) The storage unit 212 stores various data. Examples of data stored in the storage unit 212 include image data of an OCT image, image data of a fundus image, and information about the subject's eye. The information about the subject's eye includes information about the subject, such as a patient ID and name, and information about the subject's eye, such as identification information of the left eye / right eye. The storage unit 212 also stores eye examination data acquired in advance by an external device (for example, a refractometer or a subjective eye examination device), and various programs and data for operating the ophthalmic apparatus 1. The eye examination data includes the astigmatism power and astigmatism axis angle of the subject's eye. The eye examination data may further include the spherical power of the subject's eye. The eye examination data may include at least one of the spherical power, astigmatism power, and astigmatism axis angle of the subject's eye.

[0132] The storage unit 212 can also store the above-mentioned setting information. The setting information is information for setting optical conditions of the optical system constituting the ophthalmic apparatus 1. More specifically, the setting information is information for setting the optical conditions of the optical system so that the image quality of an image formed based on OCT data acquired using the optical system constituting the ophthalmic apparatus 1 is equal to or higher than a predetermined image quality level. Examples of the optical conditions of the optical system constituting the ophthalmic apparatus 1 include the focal position of the measurement light LS used in OCT, the polarization component of the measurement light LS, the aberration correction component, the optical path length difference between the measurement light LS and the reference light LR, and the position of the optical system with respect to the subject's eye E.

[0133] At least a part of the data stored in the storage unit 212 may be stored in a storage unit provided outside the ophthalmic apparatus 1. For example, the ophthalmic apparatus 1 is communicably connected to a server device having a function of storing at least a part of the data via a network such as an in-hospital LAN (Local Area Network). Here, the ophthalmic apparatus 1 and the server device may be connected via a WAN (Wide Area Network) such as the Internet. Also, the ophthalmic apparatus 1 and the server device may be connected via a network that combines a LAN and a WAN.

[0134] (Image forming unit 220) The image forming unit 220 forms image data of an OCT image of the fundus oculi Ef or the anterior part of the eye based on a detection signal (interference signal, OCT data) from the detector 125. That is, the image forming unit 220 forms an image of the subject's eye E based on a detection result of the interference light LC by the interference optical system. This processing includes processes such as noise removal (noise reduction), filtering, and FFT (Fast Fourier Transform) as in conventional swept-source type optical coherence tomography. The image data acquired in this manner is a data set including a group of image data formed by imaging reflection intensity profiles in multiple A-lines (paths of each measurement light LS in the subject's eye E).

[0135] When an OCT scan is performed for each scan region, the image forming unit 220 can form an image (OCT image) of the subject's eye E for each scan region. In this embodiment, the image forming unit 220 can form an OCT image of the subject's eye E for each scan region based on OCT data acquired under different optical conditions for each scan region.

[0136] To improve image quality, multiple data sets collected by repeating the same pattern scan multiple times can be superimposed (averaged).

[0137] The image forming unit 220 is configured to include, for example, the circuit board described above. In this specification, the "image data" may be regarded as the same as the "image" based on the image data. Also, a part of the fundus Ef may be regarded as the same as the image.

[0138] (Data processing unit 230) The data processing unit 230 performs various data processing (image processing) and analysis processing on the detection result of the interference light LC or the image formed by the image forming unit 220. For example, the data processing unit 230 executes various correction processing such as analysis of the signal-to-noise ratio of the interference signal, brightness correction of the image, and dispersion correction.

[0139] Furthermore, the data processing unit 230 performs various image processing and analysis processing on the images (fundus images, anterior eye images, etc.) obtained by the fundus camera unit 2.

[0140] The data processing unit 230 executes known image processing such as an interpolation process for interpolating pixels between two-dimensional tomographic images to form image data of a three-dimensional image of the fundus oculi Ef or the subject's eye E. The image data of a three-dimensional image means image data in which pixel positions are defined by a three-dimensional coordinate system. The image data of a three-dimensional image includes image data consisting of three-dimensionally arranged voxels. This image data is called volume data or voxel data. When an image based on the volume data is to be displayed, the data processing unit 230 performs a rendering process (such as volume rendering or MIP (Maximum Intensity Projection)) on the volume data to form image data of a pseudo three-dimensional image as viewed from a specific line of sight. The pseudo three-dimensional image is displayed on a display device such as the display unit 240A.

[0141] It is also possible to form stack data of multiple tomographic images as image data of a three-dimensional image. Stack data is image data obtained by arranging multiple tomographic images obtained along multiple scanning lines three-dimensionally based on the positional relationship of the scanning lines. In other words, stack data is image data obtained by expressing multiple tomographic images that were originally defined by individual two-dimensional coordinate systems using one three-dimensional coordinate system (i.e., embedding them in one three-dimensional space).

[0142] The data processor 230 can construct an OCTA image (blood vessel-enhanced image, angiogram) in which retinal blood vessels and choroidal blood vessels are emphasized based on data (e.g., B-scan data, OCT data) collected in time series by OCT scanning. The OCTA image may be an image showing a cross-sectional structure or a front image.

[0143] In some embodiments, the data processor 230 compares two OCT images obtained by repeatedly executing B-scans on approximately the same part of the subject's eye E, and constructs an enhanced image (motion contrast image) in which the changed part is emphasized by converting pixel values ​​of the changed part of the signal intensity into pixel values ​​corresponding to the changed part. In addition, the data processor 230 can form an OCTA (angiography) image by extracting information of a predetermined thickness in a desired part from the constructed multiple enhanced images and constructing it as an en-face image.

[0144] The data processing unit 230 can align the fundus image and the OCT image. When the fundus image and the OCT image are acquired in parallel, the fundus image and the OCT image acquired (almost) simultaneously can be aligned with each other based on the optical axis of the photographing optical system 30, since both optical systems are coaxial. Regardless of the timing of acquisition of the fundus image and the OCT image, it is also possible to align the OCT image and the fundus image by aligning the image obtained by projecting the OCT image onto the xy plane with the fundus image. This alignment method is also applicable when the optical system for acquiring the fundus image and the optical system for OCT measurement are not coaxial. Even when the optical systems are not coaxial, if the relative positional relationship between the two optical systems is known, it is possible to perform alignment similar to that in the case of the coaxial system by referring to this relative positional relationship.

[0145] Such a data processing unit 230 includes an image synthesis unit 231 and an analysis unit 232 .

[0146] (Image synthesis unit 231) The image synthesis unit 231 generates a synthetic image by synthesizing a plurality of images formed by the image forming unit 220. Specifically, the image synthesis unit 231 aligns a plurality of OCT images formed for each scan region by the image forming unit 220 to generate a synthetic image.

[0147] In some embodiments, the image synthesis unit 231 aligns multiple OCT images formed for each scan area based on different optical conditions for each scan area or setting information of the optical system corresponding to the optical conditions to generate a synthetic image.

[0148] In some embodiments, the image synthesis unit 231 aligns multiple OCT images formed for each scan area to generate a synthetic image so that the correlation value of the overlapping area where the peripheral areas of the multiple OCT images overlap is maximized.

[0149] In some embodiments, the image synthesis unit 231 aligns the multiple OCT images based on characteristic regions such as layer regions, blood vessel regions, or diseased areas depicted in the peripheral regions of each of the multiple OCT images formed for each scan region to generate a synthetic image.

[0150] (Analysis Department 232) In addition to the above-mentioned analysis process, the analysis unit 232 performs an analysis process for estimating a substantial cross-sectional structure of the subject's eye E based on OCT data obtained by a previously performed OCT scan (high-speed scan) or an OCT image formed based on the OCT data. For example, the analysis unit 232 performs an analysis process for estimating a substantial cross-sectional structure of the subject's eye E for each scan region based on OCT data or an OCT image obtained by a previously performed OCT scan for each scan region.

[0151] Such an analysis section 232 includes an image position specification section 232A and an image quality evaluation value calculation section 232B.

[0152] (Image position identification unit 232A) The image position specifying part 232A specifies the substantial cross-sectional structure of the test eye E based on the depth position of a site of interest (broadly speaking, the object to be measured (the test eye)) in the image. An example of the site of interest is the fundus Ef (retina, retinal pigment epithelium layer) whose cross-sectional shape is curved.

[0153] In some embodiments, the image position identifying part 232A identifies the position of the center of gravity in the depth direction (depth range) in a B-scan image (tomographic image) as an OCT image, and identifies the position of the site of interest in the depth direction in the B-scan image based on the identified position of the center of gravity in the depth direction. In this case, for example, the image position identifying part 232A integrates (or averages the integrated values) the pixel values ​​of the B-scan image in a direction (B-scan direction) perpendicular to the A-scan direction (depth direction). Then, the image position identifying part 232A identifies the position of the center of gravity in the depth direction based on the obtained integration profile in the A-scan direction.

[0154] In some embodiments, the image position identification unit 232A identifies an area having a predetermined shape from the OCT image as an area in which a site of interest is depicted, and identifies the depth-wise position of the identified area in the OCT image.

[0155] (Image quality evaluation value calculation unit 232B) The image quality evaluation value calculation unit 232B identifies the substantial cross-sectional structure of the subject's eye E including the site of interest based on an evaluation value (including a statistical value of the evaluation value) corresponding to the image quality (e.g., signal-to-noise ratio) of the image. The calculation process of the evaluation value is performed by analyzing the detection result of the interference light LC, or the OCT image formed by the image forming unit 220, or the divided images obtained by dividing the OCT image. The divided images may be images obtained by dividing the OCT image corresponding to each of a plurality of scan areas obtained by dividing the scan area. The divided images may also be images obtained by dividing the OCT image corresponding to each of a plurality of scan areas set in advance.

[0156] The image quality evaluation value calculation unit 232B calculates an arbitrary evaluation value that quantitatively expresses image quality. Typically, the evaluation value is calculated so that the higher the image quality (image quality), the larger the value. The calculation process of the evaluation value executed by the image quality evaluation value calculation unit 232B may be any process. For example, the image quality evaluation value calculation unit 232B can execute a process using any known technology, such as a signal-to-noise ratio (SNR), a contrast-to-noise ratio (CNR), a root-mean-square (RMS) granularity, a Wiener spectrum, a modulation transfer function (MTF), or a quality index (QI).

[0157] In a first example of the evaluation value calculation process, the image quality evaluation value calculation unit 232B calculates a differential histogram of the image to be calculated, and calculates an image quality evaluation value using the maximum value of the luminance values ​​(differential values) having a pixel number equal to or greater than a predetermined ratio in the entire image in the calculated differential histogram. Specifically, the image quality evaluation value calculation unit 232B calculates the difference between the maximum and minimum differential values ​​at or above a predetermined threshold value (e.g., 20%) as the image quality evaluation value. In this case, the image quality evaluation value indicates a high value when the image quality is equal to or greater than a predetermined image quality level, and decreases as the image quality deviates from the predetermined image quality level.

[0158] In a second example of the evaluation value calculation process, the data processing unit 230 (or the analysis unit 232) applies a predetermined analysis process (for example, a segmentation process) to an evaluation area set for an image corresponding to a predetermined part of the subject's eye E. Thereby, the image quality evaluation value calculation unit 232B specifies an image area (signal area) corresponding to a desired part (tissue) and the other image area (non-signal area). Next, the image quality evaluation value calculation unit 232B generates a histogram of luminance in the signal area and a histogram of luminance in the non-signal area. Then, the image quality evaluation value calculation unit 232B calculates an evaluation value corresponding to the image quality from the degree of overlap of these two histograms. For example, the evaluation value is defined in the range of 0 to 100 so that the evaluation value=0 when both histograms completely overlap, and the evaluation value=100 when both histograms are completely separated. This evaluation calculation may include, for example, normalization of two histograms, generation of a probability distribution function, calculation of an evaluation value using a predetermined calculation formula, and the like.

[0159] Furthermore, the image quality evaluation value calculation unit 232B may calculate known parameters expressing image quality, such as a signal-to-noise ratio (SNR), spatial resolution, contrast, etc., for the image to be calculated. In this case, the image quality evaluation value indicates a high value when the image quality is equal to or higher than a predetermined image quality level, and decreases as the image quality deviates from the predetermined image quality level.

[0160] The image quality evaluation value calculation section 232B calculates an evaluation value of the image quality of the entire OCT image, or an evaluation value of the image quality for each of the divided images corresponding to each of the multiple scan regions.

[0161] Furthermore, the image quality evaluation value calculation unit 232B can calculate statistics of multiple evaluation values ​​for multiple divided images. Examples of the statistics include maximum value, minimum value, median value, average value, mode value, range, variance, standard deviation, a weighted average value in which the weighting coefficient increases the closer to the target part (the optical axis of the optical system), or a value of a predetermined evaluation formula using any of the above statistics.

[0162] An example of the evaluation formula is one in which the value VCCQ of the evaluation formula increases as the total value of the evaluation values ​​of the multiple divided images increases and the variation in the evaluation values ​​of the multiple divided images decreases. In this case, for example, the value VCCQ of the evaluation formula is the sum of the evaluation values ​​of the multiple divided images divided by (the standard deviation of the multiple evaluation values ​​+ 1).

[0163] The main controller 211 estimates the analysis result obtained by the analyzer 232 as the substantial cross-sectional structure of the subject's eye E, and changes the optical conditions of the optical system in synchronization with the period of the slow scan based on the estimated cross-sectional structure. In some embodiments, the main controller 211 estimates the substantial cross-sectional structure of the subject's eye E for each scan region, and changes the optical conditions of the optical system in synchronization with the period of the slow scan based on the estimated cross-sectional structure.

[0164] The data processing unit 230 that functions as described above includes, for example, the above-mentioned processor, RAM, ROM, a hard disk drive, a circuit board, etc. A computer program that causes the microprocessor to execute the above-mentioned functions is stored in advance in a storage device such as a hard disk drive.

[0165] (User Interface 240) The user interface 240 includes a display unit 240A and an operation unit 240B. The display unit 240A includes the display device of the arithmetic control unit 200 and the display device 3 described above. The operation unit 240B includes the operation device of the arithmetic control unit 200 described above. The operation unit 240B may include various buttons and keys provided on the housing of the ophthalmic apparatus 1 or on the outside. For example, when the fundus camera unit 2 has a housing similar to that of a conventional fundus camera, the operation unit 240B may include a joystick, an operation panel, etc. provided on this housing. In addition, the display unit 240A may include various display devices such as a touch panel provided on the housing of the fundus camera unit 2.

[0166] It is not necessary for the display unit 240A and the operation unit 240B to be configured as separate devices. For example, it is possible to use a device in which the display function and the operation function are integrated, such as a touch panel. In that case, the operation unit 240B is configured to include this touch panel and a computer program. The operation content on the operation unit 240B is input to the control unit 210 as an electric signal. Also, operations and information input may be performed using a graphical user interface (GUI) displayed on the display unit 240A and the operation unit 240B.

[0167] The subject's eye E (fundus Ef, anterior segment) is an example of an "object to be measured" according to the embodiment. The optical system, the optical path length changing unit 41, the OCT focusing lens 45, and the VCC lens 47 (interference optical system) included in the OCT unit 100 are an example of an "optical system" according to the embodiment. The OCT focusing lens 45, the corner cube 114, the optical path length changing unit 41, and the polarization controller 103 are an example of "one or more optical elements" according to the embodiment. The focusing position of the measurement light LS, the polarization component of the measurement light LS, the aberration correction component, the optical path length difference between the measurement light LS and the reference light LR, or the position of the optical system with respect to the subject's eye E are an example of an "optical condition of the optical system" according to the embodiment. The ophthalmic device 1 is an example of an "OCT device" according to the embodiment. The optical path length changing unit 41, or the corner cube 114 and the reference driving unit 114A are an example of an "optical path length difference changing member" according to the embodiment. The OCT focusing lens 45 is an example of a "focusing lens" according to the embodiment. The VCC lens 47 is an example of an "aberration correction device" according to the embodiment. The display device 3 or the display unit 240A is an example of a "display unit" according to the embodiment.

[0168] Hereinafter, a case will be described in which the ophthalmic apparatus 1 according to the first embodiment executes an ammonite scan as an OCT scan on the subject's eye E. However, this embodiment can also be applied to a case in which an OCT scan is executed on the subject's eye E in a scan mode other than the ammonite scan.

[0169] FIG. 6 shows an explanatory diagram of an ammonite scan according to the first embodiment.

[0170] The Ammonite scan according to the first embodiment is a scan mode in which the scan center position of the high-speed scan is moved along the scan pattern (scan trajectory) of the low-speed scan, and one or more high-speed scans are sequentially performed in a scan pattern defined based on the moved scan center position. In the Ammonite scan according to the present embodiment, the high-speed scan is a circle scan, the low-speed scan is a spiral scan, and the sequentially performed circle scans are performed so as to intersect with the scan pattern of the immediately preceding circle scan. In other words, the circle scans are sequentially performed so that the scan patterns of two adjacent circle scans intersect.

[0171] In FIG. 6, the scan pattern Lsc for the slow scan is shown diagrammatically, and the scan pattern HS for the fast scan is shown diagrammatically. n (n is an integer of 4 or more), HS n-1 , H.S. n-2 , H.S. n-3 is shown diagrammatically.

[0172] As described above, the Ammonite scan combines low-speed scanning and high-speed scanning, and can perform scanning of the subject's eye E from various scanning directions with simple control. In particular, it is possible to perform high-density scanning in a short period of time in the area near the center of the Ammonite scan (the center position of the low-speed scan), and low-density scanning over a longer period of time as the area moves away from the center, and thus it is possible to scan a wide-angle area including the area of ​​interest with simple control.

[0173] According to this embodiment, by scanning the subject's eye E with an ammonite scan, it becomes possible to measure or photograph the subject's eye E at a wider angle with higher image quality, regardless of the cross-sectional structure of the subject's eye E.

[0174] Fig. 7 shows a schematic diagram of an OCT image formed based on OCT data obtained by ammonite scanning according to the first embodiment. For convenience of explanation, Fig. 7 shows a case where an OCTA image is generated, but the same applies to an OCT image.

[0175] First, the main controller 211 sets a scan area for the ammonite scan with respect to the subject's eye E. Setting parameters for setting the scan area for the ammonite scan include the scan start position of the low-speed scan (scan center position of the low-speed scan), the scan end position of the low-speed scan, the scan speed of the low-speed scan, the rate of change of the scan radius from the scan start position of the low-speed scan, the scan speed of the high-speed scan, and the scan radius of the high-speed scan.

[0176] The main controller 211 controls the optical scanner 42, the OCT unit 100, etc., to move the scan center position of the high-speed scan along the scan pattern of the low-speed scan, and repeat two or more high-speed scans (circle scans) centered on the scan center position after the movement. The main controller 211 controls the image forming unit 220 to form an OCT image (tomographic image, B-scan image) based on the acquired OCT data every time a circle scan is performed. Next, the main controller 211 controls the data processing unit 230 to sequentially form OCTA images by comparing two OCT images obtained by repeatedly performing circle scans (B-scans) on approximately the same part of the subject's eye E. As a result, an OCTA image IMG is formed in which OCTA images formed in the high-speed scan direction are arranged in the low-speed scan direction.

[0177] Next, the main controller 211 controls the data processor 230 to perform coordinate conversion to a Cartesian coordinate system for each of the multiple OCTA images formed in the fast scan direction, and generate strip images ST0, ST1, ST2, ... For example, a strip image ST0 is obtained by a circle scan of the scan pattern HS0 in Fig. 6, a strip image ST1 is obtained by a circle scan of the scan pattern HS1 intersecting with the scan pattern HS0, and a strip image ST2 is obtained by a circle scan of the scan pattern HS2 intersecting with the scan pattern HS1. At this time, it is possible to thin out OCTA images in which artifacts have occurred due to the movement or blinking of the subject's eye E during the circle scan, and to perform coordinate conversion only on OCTA images in which artifacts have not occurred to obtain strip images.

[0178] The main controller 211 controls the data processor 230 to sequentially align the strip images ST1, ST2, ... with the strip image ST0 as a reference image, thereby generating composite images CIMG0, CIMG1, CIMG2, ..., CIMGm (m is an integer equal to or greater than 2). The data processor 230 performs the alignment based on images within the overlapping scan regions of two adjacent strip images (e.g., blood vessel regions in an OCTA image).

[0179] This allows the ammonite scan in Figure 6 to obtain the composite image CIMGm in Figure 7.

[0180] [Example] An example of the operation of the ophthalmologic apparatus 1 according to the first embodiment will be described.

[0181] 8 to 13B show an example of the operation of the ophthalmologic apparatus 1 according to the first embodiment.

[0182] Fig. 8 is a schematic diagram showing an example of a plurality of scan areas obtained by dividing a scan area of ​​an OCT scan performed in the ophthalmic apparatus 1 according to the first embodiment. In Fig. 8, the same parts as those in Fig. 6 are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0183] For example, as shown in Fig. 8, the main controller 211 sets a central region SAR1 including the optical axis of the optical system in the subject's eye E, an intermediate region SAR2 around the central region SAR1, and a peripheral region SAR3 around the intermediate region SAR2. The intermediate region SAR2 is disposed outside the central region SAR1 and surrounds the central region SAR1. In Fig. 8, the intermediate region SAR2 may be two or more regions disposed concentrically. The peripheral region SAR3 is disposed outside the outermost intermediate region among one or more intermediate regions including the central region SAR1 and surrounds the outermost intermediate region.

[0184] The main controller 211 can change the optical conditions of the optical system for each region shown in Fig. 8. This makes it possible to obtain an OCT image of the subject's eye E with good image quality without performing a pre-scan while minimizing changes in the image caused by changes in the optical conditions during scanning when photographing the subject at a wide angle.

[0185] Fig. 9 is a timing diagram showing an example of timing of changing the optical system during a single scan performed in the ophthalmic apparatus 1 according to the first embodiment. In Fig. 9, the horizontal axis represents time, and the vertical axis typically represents the signal level of a control signal for controlling each control timing.

[0186] The main controller 211 changes the optical conditions of the optical system in synchronization with the control timing of the slow scan (the period of the slow scan) during a single scan in which a fast scan (circle scan) controlled with a period Tfc and a slow scan (spiral scan) controlled with a period Tsc (>Tfc) are combined and executed as shown in Fig. 9. The timing of changing the optical conditions of the optical system may be between the execution timings of two consecutive A-scans.

[0187] That is, the main controller 211 sequentially executes OCT scans shown in Fig. 6 on a preset scan area of ​​the fundus Ef. The main controller 211 controls the image forming unit 220 to form an OCT image every time OCT data is acquired by an OCT scan. Furthermore, the main controller 211 controls the analysis unit 232 to analyze the OCT image formed by the image forming unit 220 and calculate the position of the site of interest in the OCT image and the image quality evaluation value of the OCT image. Next, the main controller 211 changes the optical conditions of the optical system based on the position of the site of interest in the OCT image and the image quality evaluation value of the OCT image in synchronization with the start timing of the low-speed scan of the next OCT scan, as shown in Fig. 9.

[0188] Fig. 10 shows a schematic diagram of the focal position of the measuring light LS which differs for each scan region in the B-scan image acquired by the ophthalmic apparatus 1 according to the first embodiment. In Fig. 10, the focal positions of the measuring light LS in the divided images obtained by dividing the B-scan image IMG10 according to the scan regions are shown as beam waists Bw1 to Bw6.

[0189] A B-scan image IMG10 shown in FIG. 10 is a tomographic image obtained when the OCT focusing lens 45 is moved for each scan region so that the focal position of the measurement light LS is located on the retinal pigment epithelium layer of the fundus Ef or in its vicinity.

[0190] For example, the main controller 211 executes an OCT scan (e.g., a circle scan) in advance at a scan position different from the fundus Ef in the B-scan image IMG10 shown in Fig. 10. Then, the main controller 211 moves the OCT focusing lens 45 in synchronization with the start timing of the low-speed scan for each scan region based on this OCT data or a B-scan image formed based on the OCT data. This makes it possible to acquire a tomographic image of the fundus Ef with good image quality even when an OCT scan is performed on the fundus Ef at a wide angle.

[0191] Fig. 11 shows a schematic diagram of a tomographic image when the optical path length difference between the measurement light LS and the reference light LR is changed for each scan region by the ophthalmic apparatus 1 according to the first embodiment. Fig. 11 shows divided images IMG21 to IMG26 obtained by dividing the B-scan image corresponding to the scan region.

[0192] For example, the main controller 211 executes an OCT scan (e.g., a circle scan) in advance. Then, based on this OCT data or a B-scan image formed based on the OCT data, the main controller 211 controls the optical path length changer 41 and at least one of the corner cube 114 and the reference driver 114A in synchronization with the start timing of the low-speed scan for each scan region. In this case, the main controller 211 controls the image synthesis unit 231 to align the divided images IMG21 to IMG26 in the depth direction to generate a synthetic image in which the site of interest (retinal pigment epithelium layer) of the fundus Ef is smoothly connected. This makes it possible to obtain a tomographic image of the fundus Ef with good image quality even when an OCT scan is performed on the fundus Ef at a wide angle.

[0193] 12A and 12B are flowcharts showing an example of the operation of the ophthalmologic apparatus 1 according to the first embodiment. A computer program for implementing the processes shown in Fig. 12A and 12B is stored in the storage unit 212. The main control unit 211 operates according to the computer program to execute the processes shown in Fig. 12A and 12B.

[0194] Figures 13A and 13B show a flowchart of an example of the operation of step S6 in Figure 12A. A computer program for realizing the processing shown in Figures 13A and 13B is stored in the storage unit 212. The main control unit 211 operates according to this computer program to execute the processing shown in Figures 13A and 13B.

[0195] (S1: Set the optical system to the reference position) As shown in FIG. 12A, first, the main controller 211 sets the optical conditions of the optical system constituting the ophthalmic apparatus 1 to predetermined initial conditions, and sets the optical system to a reference position based on the set initial conditions.

[0196] (S2: Alignment) Next, in a state where the fixation target is presented at a predetermined fixation position, the main controller 211 performs alignment adjustment of the optical system with respect to the subject's eye E. As an example of the alignment adjustment, there is a case where it is performed manually and a case where it is performed automatically.

[0197] When performing the alignment adjustment manually, the main controller 211 projects a pair of alignment indicators onto the subject's eye E using the alignment optical system 50. A pair of alignment bright spots are displayed on the display unit 240A as received light images of these alignment indicators. The main controller 211 also causes the display unit 240A to display an alignment scale indicating positions to which the pair of alignment bright spots are to be moved. The alignment scale is, for example, a bracket-shaped image.

[0198] When the positional relationship between the subject's eye E and the fundus camera unit 2 (objective lens 22) is appropriate, i.e., when the distance (working distance) between the subject's eye E and the fundus camera unit 2 is appropriate and the optical axis of the optical system of the fundus camera unit 2 and the eye axis (corneal apex position) of the subject's eye E are (almost) aligned, a pair of alignment bright spots are first imaged at a predetermined position (for example, an intermediate position between the corneal apex and the center of corneal curvature) and then projected onto the subject's eye E by a known method. The examiner (user) can adjust the alignment of the optical system with respect to the subject's eye E by moving the fundus camera unit 2 three-dimensionally so as to guide the pair of alignment bright spots into the alignment scale.

[0199] When alignment adjustment is performed automatically, a moving mechanism 150 is used to move the fundus camera unit 2. The data processing unit 230 identifies the position of each alignment bright point on the screen displayed on the display unit 240A, and calculates the displacement between the identified position of each alignment bright point and the alignment scale. The main control unit 211 moves the fundus camera unit 2 by the moving mechanism 150 so as to cancel this displacement. The position of each alignment bright point can be specified, for example, by calculating the luminance distribution of each alignment bright point and calculating the center of gravity position based on this luminance distribution. Since the position of the alignment scale is constant, it is possible to calculate the target displacement by, for example, calculating the displacement between the center position and the above-mentioned center of gravity position. The moving direction and moving distance of the fundus camera unit 2 can be determined by referring to the unit moving distance in each of the x, y, and z directions set in advance (for example, the result of measuring in advance how much the alignment indicator moves in which direction when the fundus camera unit 2 is moved in which direction). The main controller 211 generates a signal according to the determined moving direction and moving distance, and transmits this signal to the moving mechanism 150. Thereby, the position of the optical system with respect to the subject's eye E is automatically adjusted.

[0200] (S3: Set the scan area) The main controller 211 sets a scan area so that a site of interest in the subject's eye E is located at the scan center position (a position corresponding to the optical axis of the optical system). For example, as shown in Fig. 6 or 8, the main controller 211 sets an ammonite scan as the scan mode and sets a plurality of scan areas to be scanned.

[0201] (S4: OCT scan) Next, the main controller 211 controls the optical scanner 42, the OCT unit 100, etc. to perform an ammonite scan on the scan area set in step S3. In step S4, an ammonite scan is performed across multiple scan areas as shown in FIG.

[0202] (S5: Forming an OCT image) Next, the main controller 211 controls the image forming unit 220 to sequentially form OCT images based on the OCT data obtained by the OCT scans of the multiple scan regions sequentially performed in step S4.

[0203] In some embodiments, the main controller 211 controls the image synthesizer 231 to align the multiple OCT images formed in step S5 to generate a synthetic image. The synthetic image is one of the OCT images.

[0204] (S6:Analysis) Next, the main controller 211 controls the analyzer 232 to execute an analysis process on the OCT image (or composite image) formed in step S5. In step S6, the position of the region of interest in the OCT image or composite image formed in step S5 and the image quality evaluation value of the OCT image or composite image are calculated.

[0205] Step S6 will be described later in detail.

[0206] (S7: Change the optical conditions of the optical system?) Next, the main controller 211 determines whether or not to change the optical conditions of the optical system based on the processing result obtained by the analysis processing executed in step S6. For example, the main controller 211 determines whether or not there are optical conditions of the optical system to be changed as a result of the analysis processing in step S6, thereby determining whether or not to change the optical conditions of the optical system.

[0207] Specifically, the main controller 211 determines to change the optical conditions of the optical system when at least one of the correction amount of the optical path length difference between the measurement light LS and the reference light LR, the correction amount of the focal position of the measurement light LS, the correction amount of the polarization state of the light L0 from the light source unit 101 or the measurement light LS, the aberration correction amount, and the movement correction amount of the optical system is specified. On the other hand, the main controller 211 determines not to change the optical conditions of the optical system when none of the above correction amounts is specified.

[0208] When it is determined in step S7 that the optical conditions of the optical system are to be changed (S7: Y), the operation of the ophthalmic apparatus 1 proceeds to step S8. When it is determined in step S7 that the optical conditions of the optical system are not to be changed (S7: N), the operation of the ophthalmic apparatus 1 proceeds to step S10.

[0209] (S8: When does slow scan start?) When it is determined in step S7 that the optical conditions of the optical system are to be changed (S7: Y), the main controller 211 determines whether it is time to start a slow scan constituting an ammonite scan. For example, the main controller 211 determines whether it is time to start a slow scan (spiral scan) based on the control content for the optical scanner 42 to execute an OCT scan on the scan area set in step S3.

[0210] When it is determined in step S8 that it is time to start a low-speed scan (S8: Y), the operation of the ophthalmic apparatus 1 proceeds to step S9. When it is determined in step S8 that it is not time to start a low-speed scan (S8: N), the operation of the ophthalmic apparatus 1 repeats step S8.

[0211] (S9: Change the optical conditions of the optical system) When it is determined in step S8 that it is time to start a slow scan (S8: Y), the main controller 211 changes the optical conditions of the optical system.

[0212] For example, the main control unit 211 changes the optical conditions of the optical system by controlling the OCT focusing drive unit 45A to move the position on the optical axis of the OCT focusing lens 45 by an amount corresponding to the correction amount of the focusing position identified in step S6.

[0213] For example, the main control unit 211 changes the optical conditions of the optical system by controlling the polarization controller 103 to change the polarization component of the light L0 by an amount corresponding to the correction amount of the polarization state identified in step S6.

[0214] For example, the main control unit 211 changes the optical conditions of the optical system by controlling the VCC driving unit 47A to change the cylindrical power or the cylindrical axis angle of the VCC lens 47 by an amount corresponding to the amount of aberration correction identified in step S6.

[0215] For example, the main control unit 211 controls the optical path length change unit 41 or the reference driving unit 114A to change the optical conditions of the optical system by moving the position of the optical path length change unit 41 (corner cube) in the optical path of the measurement light LS or the position of the corner cube 114 in the optical path of the reference light LR by the correction amount of the optical path length difference identified in step S6.

[0216] For example, the main control unit 211 controls the movement mechanism 150 to change the optical conditions of the optical system by moving the position of the optical system in the optical axis direction relative to the test eye E or the position in the direction intersecting the optical axis of the optical system by the movement correction amount of the optical system identified in step S6.

[0217] (S10:OCT scan completed?) Following step S9, the main controller 211 determines whether to end the OCT scan. For example, the main controller 211 determines whether to end the OCT scan based on the control content for the optical scanner 42 to perform the OCT scan on the scan area set in step S3.

[0218] When it is determined in step S10 that the OCT scan is to be ended (S10: Y), the operation of the ophthalmic apparatus 1 proceeds to step S11. When it is determined in step S10 that the OCT scan is not to be ended (S10: N), the operation of the ophthalmic apparatus 1 proceeds to step S4.

[0219] (S11: OCT image synthesis) When it is determined in step S10 that the OCT scan is to be ended (S10: Y), the main controller 211 controls the image synthesis unit 231 to align the multiple OCT images formed in step S5 to generate a synthetic image. If a synthetic image has already been generated, step S11 may be omitted.

[0220] (S12:Display) Following step S11, the main control unit 211, as a display control unit, causes the display unit 240A (or the display device 3) to display the composite image generated in step S11.

[0221] In some embodiments, the main controller 211 causes the display unit 240A to display the correction amount (adjustment amount) of the optical condition of the optical system identified in step S6 for each scan region.

[0222] This is the end of the operation of the ophthalmologic apparatus 1 (END).

[0223] 12A, the processes shown in Fig. 13A and Fig. 13B are performed on the OCT images formed in step S5. Prior to the process of step S6, the image synthesis unit 231 generates a synthetic image from the multiple OCT images formed in step S5.

[0224] (S21: Identify image position) In step S6 of FIG. 12A, the main controller 211 controls the image position specifying part 232A to specify the position (imaging position) in the depth direction of the site of interest in the OCT image formed in step S5.

[0225] For example, as described above, the image position specifying unit 232A specifies the position of the center of gravity in the depth direction in the OCT image, and specifies the position of the site of interest in the depth direction in the OCT image based on the specified position of the center of gravity in the depth direction.

[0226] (S22: Adjust image position?) Next, the main controller 211 determines whether or not to adjust the depiction position in the depth direction of the region of interest in the OCT image identified in step S21. For example, the main controller 211 determines whether or not to adjust the depiction position in the depth direction of the region of interest in the OCT image identified in step S21 by determining whether or not the depiction position in the depth direction of the region of interest in the OCT image is within a predetermined depth range.

[0227] When it is determined in step S22 that the imaging position of the region of interest in the OCT image in the depth direction should be adjusted (S22: Y), the process of step S6 proceeds to step S23. When it is determined in step S22 that the imaging position of the region of interest in the OCT image in the depth direction should not be adjusted (S22: N), the process of step S6 proceeds to step S24.

[0228] (S23: Identify the correction amount for the optical path length difference) When it is determined in step S22 that the imaging position in the depth direction of the site of interest in the OCT image should be adjusted (S22: Y), the main controller 211 specifies the correction amount of the optical path length difference between the measurement light LS and the reference light LR.

[0229] For example, the main controller 211 specifies a correction amount of the optical path length difference between the measurement light LS and the reference light LR based on a displacement of the imaging position in the depth direction of the region of interest in the OCT image specified in step S21 relative to a reference depth position in a predetermined depth range. That is, the main controller 211 specifies a correction amount of the optical path length difference between the measurement light LS and the reference light LR so that the imaging position in the depth direction of the region of interest in the OCT image specified in step S21 coincides with the reference depth position in the predetermined depth range. Examples of the reference depth position include a center position (or a center of gravity position) in the predetermined depth range, an upper limit position in a reference range predetermined within the above depth range, and a lower limit position in a reference range predetermined within the above depth range.

[0230] (S24: Calculate image quality evaluation value) When it is determined in step S22 that the depth-wise depiction position of the area of ​​interest in the OCT image should not be adjusted (S22:N), or following step S23, the main controller 211 controls the image quality evaluation value calculator 232B to calculate the image quality evaluation value of the OCT image (synthetic image) formed in step S5.

[0231] For example, the main controller 211 controls the image quality evaluation value calculator 232B to calculate an image quality evaluation value for each of the multiple OCT images formed for each scan region in step S5.

[0232] (S25: Adjust the focus position?) Following step S24, the main controller 211 determines whether or not to adjust the focus position of the measurement light LS based on the image quality evaluation value calculated in step S24. In this embodiment, the main controller 211 determines whether or not to adjust the focus position of the measurement light LS for each of the multiple OCT images based on the image quality evaluation value calculated for each of the multiple OCT images in step S24.

[0233] For example, the main control unit 211 determines whether or not to adjust the focus position of the measurement light LS based on a comparison result between a predetermined reference image quality evaluation value and the image quality evaluation value calculated in step S24.

[0234] When it is determined in step S25 that the focal position of the measurement light LS should be adjusted (S25: Y), the process of step S6 proceeds to step S26. When it is determined in step S25 that the focal position of the measurement light LS should not be adjusted (S25: N), the process of step S6 proceeds to step S27.

[0235] (S26: Identify the amount of correction for the focus position) When it is determined in step S25 that the focal position of the measurement light LS should be adjusted (S25: Y), the main controller 211 specifies the correction amount of the focal position of the measurement light LS.

[0236] For example, the main controller 211 compares a predetermined reference image quality evaluation value with the image quality evaluation value calculated in step S24, and specifies a correction amount for the focal position of the measurement light LS for each of the multiple OCT images so that the image quality of the OCT image formed in step S5 is higher than the image quality corresponding to the reference image quality evaluation value. In some embodiments, the main controller 211 specifies an adjustment direction for the focal position of the measurement light LS based on the displacement of the scan area relative to the deepest part of the cross-sectional shape of the fundus Ef, and specifies a correction amount for the focal position of the measurement light LS in the specified adjustment direction.

[0237] (S27: Adjust the polarization state?) When it is determined in step S25 that the focal position of the measurement light LS should not be adjusted (S25:N), or following step S26, the main controller 211 determines whether or not the polarization state of the light L0 from the light source unit 101 or the measurement light LS should be adjusted based on the image quality evaluation value calculated in step S24. In this embodiment, the main controller 211 determines whether or not the polarization state of the light L0 or the measurement light LS should be adjusted for each of the multiple OCT images based on the image quality evaluation value calculated for each of the multiple OCT images in step S24.

[0238] For example, the main control unit 211 determines whether or not to adjust the polarization state of the light L0 or the measurement light LS based on a comparison result between a predetermined reference image quality evaluation value and the image quality evaluation value calculated in step S24. In some embodiments, polarization information that associates the comparison result between the reference image quality evaluation value and the calculated image quality evaluation value with the polarization state is stored in advance in the storage unit 212, and the main control unit 211 determines whether or not to adjust the polarization state of the light L0 or the measurement light LS by referring to the polarization information stored in the storage unit 212.

[0239] When it is determined in step S27 that the polarization state of the light L0 or the measurement light LS should be adjusted (S27: Y), the process of step S6 proceeds to step S28. When it is determined in step S27 that the polarization state of the light L0 or the measurement light LS should not be adjusted (S27: N), the process of step S6 proceeds to step S29.

[0240] (S28: Identify the amount of correction for the polarization state) When it is determined in step S27 that the polarization state of the light L0 or the measurement light LS should be adjusted (S27: Y), the main controller 211 specifies the correction amount of the polarization state of the light L0 or the measurement light LS.

[0241] For example, the main controller 211 compares a predetermined reference image quality evaluation value with the image quality evaluation value calculated in step S24, and specifies the amount of correction for the polarization state of the light L0 or the measurement light LS for each of the multiple OCT images such that the image quality of the OCT image formed in step S5 is higher than the image quality corresponding to the reference image quality evaluation value. In some embodiments, the main controller 211 refers to the above polarization information to specify an adjustment direction for the polarization state of the measurement light LS of the light L0, and specifies the amount of correction for the polarization state of the light L0 or the measurement light LS in the specified adjustment direction.

[0242] (S29: Adjust the aberration?) Next, when it is determined in step S27 that the polarization state of the light L0 or the measurement light LS should not be adjusted (S27: N), or following step S28, the main controller 211 determines whether or not to adjust the aberration based on the image quality evaluation value calculated in step S24. In this embodiment, the main controller 211 determines whether or not to adjust the aberration for each of the multiple OCT images based on the image quality evaluation value calculated for each of the multiple OCT images in step S24.

[0243] For example, the main control unit 211 determines whether or not to adjust the aberration based on a comparison result between a predetermined reference image quality evaluation value and the image quality evaluation value calculated in step S24. In some embodiments, aberration information that associates the comparison result between the reference image quality evaluation value and the calculated image quality evaluation value with the aberration is stored in advance in the storage unit 212, and the main control unit 211 determines whether or not to adjust the aberration by referring to the aberration information stored in the storage unit 212.

[0244] When it is determined in step S29 that the polarization state of the light L0 or the measurement light LS should be adjusted (S29: Y), the process of step S6 proceeds to step S30. When it is determined in step S29 that the aberration should not be adjusted (S29: N), the process of step S6 proceeds to step S31.

[0245] (S30: Identify the amount of aberration correction) When it is determined in step S29 that the aberration should be adjusted (S29: Y), the main controller 211 specifies the amount of aberration correction.

[0246] For example, the main controller 211 compares a predetermined reference image quality evaluation value with the image quality evaluation value calculated in step S24, and specifies an amount of aberration correction for each of the multiple OCT images such that the image quality of the OCT image formed in step S5 is higher than the image quality corresponding to the reference image quality evaluation value. In some embodiments, the main controller 211 refers to the above aberration information to specify an adjustment direction for the polarization state of the measurement light LS of the light L0, and specifies an amount of aberration correction in the specified adjustment direction.

[0247] (S31: Adjust alignment position?) Following step S30, when it is determined in step S29 that the aberration should not be adjusted (S29:N), or following step S30, the main control unit 211 determines whether or not the alignment position of the optical system with respect to the test eye E should be adjusted based on the image quality evaluation value calculated in step S24.

[0248] In some embodiments, the main controller 211 determines whether or not to adjust the alignment position for each of the multiple OCT images based on the image quality evaluation value calculated for each of the multiple OCT images in step S24. For example, the main controller 211 determines whether or not to adjust the alignment position based on a comparison result between a predetermined reference image quality evaluation value and the image quality evaluation value calculated in step S24.

[0249] In some embodiments, the main controller 211 determines whether or not to adjust the alignment position based on the depiction position of the region of interest in the OCT image identified by the image position identifying part 232 A. For example, the main controller 211 determines whether or not to adjust the alignment position based on the displacement of the position of the region of interest in the OCT image identified by the image position identifying part 232 A relative to a predetermined reference position.

[0250] When it is determined in step S31 that the alignment position should be adjusted (S31: Y), the process of step S6 proceeds to step S32. When it is determined in step S31 that the alignment position should not be adjusted (S31: N), the process of step S6 ends (END).

[0251] (S32: Identify the amount of optical system movement correction) When it is determined in step S31 that the alignment position should be adjusted (S32: Y), the main controller 211 specifies the amount of movement correction of the optical system.

[0252] For example, the main controller 211 compares a predetermined reference image quality evaluation value with the image quality evaluation value calculated in step S24, and specifies the amount of movement correction of the optical system so that the image quality of the OCT image formed in step S5 is higher than the image quality corresponding to the reference image quality evaluation value. In some embodiments, the main controller 211 specifies the amount of movement correction of the optical system for each scan region. In some embodiments, the main controller 211 specifies a single amount of movement correction of the optical system so that a statistical value (e.g., average value) of the image quality evaluation values ​​is maximized.

[0253] For example, the main controller 211 specifies the amount of movement correction of the optical system based on the displacement of the position of the site of interest in the OCT image specified by the image position specifying part 232A relative to a predetermined reference position.

[0254] When it is determined in step S31 that the alignment position should not be adjusted (S31: N), or following step S32, the process of step S6 ends (END).

[0255] The order of changing the optical conditions of the optical system according to the embodiment is not limited to the order of changing shown in Fig. 13A and Fig. 13B. Moreover, the optical conditions of the optical system changed in the embodiment may include at least one of the optical conditions shown in Fig. 13A and Fig. 13B.

[0256] As described above, according to the first embodiment, when an OCT scan is performed on the subject's eye E by combining a low-speed scan and a high-speed scan, the cross-sectional structure of the subject's eye E is substantially estimated based on OCT data or an OCT image obtained by a high-speed scan previously performed, and the optical conditions of the optical system are changed in synchronization with the period of the low-speed scan based on the estimated cross-sectional structure. As a result, when the subject's eye E is photographed at a wide angle without performing a pre-scan, an image of the subject's eye E with good image quality can be obtained.

[0257] <Second embodiment> In the first embodiment, the ophthalmic apparatus is provided with the VCC lens 47 as the aberration correction device, but the configuration according to the embodiment is not limited to this. For example, the ophthalmic apparatus according to the embodiment may be configured to include a wavefront aberration correction optical system as the aberration correction device.

[0258] The configuration according to the second embodiment will be described below, focusing on the differences from the configuration according to the first embodiment.

[0259] Fig. 14 shows an example of the configuration of an optical system of an ophthalmic apparatus 1a according to the second embodiment. In Fig. 14, the same parts as those in Fig. 1 are given the same reference numerals, and the description thereof will be omitted as appropriate.

[0260] The configuration of the optical system of the ophthalmic device 1a of the second embodiment differs from the configuration of the optical system of the ophthalmic device 1 of the first embodiment in that a fundus camera unit 2a is provided instead of the fundus camera unit 2, and that an arithmetic control unit 200a is provided instead of the arithmetic control unit 200.

[0261] The configuration of the fundus camera unit 2a differs from the configuration of the fundus camera unit 2 in that a wavefront aberration correction optical system 70 is provided instead of the VCC lens 47. The arithmetic and control unit 200a differs from the arithmetic and control unit 200 in that the arithmetic and control unit 200a controls the wavefront aberration correction optical system 70 instead of the VCC lens 47.

[0262] The wavefront aberration correction optical system 70 includes a beam splitter 71 , a transmission type compensation optical element 72 , a relay lens 73 , a lens array 74 , and a wavefront sensor 75 .

[0263] 14, a beam splitter 71 and a compensation optical element 72 are disposed between the collimator lens unit 40 and the optical path length changer 41. The compensation optical element 72 is disposed between the beam splitter 71 and the optical path length changer 41.

[0264] The beam splitter 71 splits the return light of the measurement light LS into light guided to the collimator lens unit 40 side and light guided to the relay lens 73 side. The beam splitter 71 may be capable of changing the splitting ratio of these lights. For example, when the compensation optical element 72 described later is controlled (e.g., during provisional measurement), the return light of the measurement light LS is split into two lights with a splitting ratio of "50:50". When the compensation optical element 72 is not controlled (e.g., during actual measurement), the return light of the measurement light LS can be split into two lights with a splitting ratio of "90:10" so that the amount of light guided to the collimator lens unit 40 side is increased.

[0265] The adaptive optical element 72 may be, for example, a deformable phase plate (DPP). The adaptive optical element 72 is an optical element that can locally change the phase of the wavefront of light passing through it.

[0266] A relay lens 73, a lens array 74, and a wavefront sensor 75 are arranged in the reflection direction of the beam splitter 71. The compensation optical element 72 and the lens array 74 are each arranged at a position optically conjugate with the pupil of the subject's eye E (pupil conjugate position) or in the vicinity thereof.

[0267] The beam splitter 71 transmits and guides the measurement light LS from the collimator lens unit 40 to a compensation optical element 72, and also guides the return light of the measurement light LS from the test eye E that passes through the compensation optical element 72 to a relay lens 73. The compensation optical element 72 corrects at least the wavefront aberration of the return light of the measurement light LS. The return light of the measurement light LS guided to the relay lens 73 passes through the relay lens 73 and is guided to the lens array 74.

[0268] The lens array 74 includes a plurality of lenses arranged in an array, and generates a plurality of focused beams from the light that has passed through the relay lens 73. The plurality of focused beams generated by the lens array 74 are irradiated onto a sensor surface of the wavefront sensor 75. The wavefront sensor 75 may be, for example, a CMOS image sensor or a CCD image sensor.

[0269] It is possible to locally change the wavefront of the light passing through the compensation optical element 72 according to the detection results of the multiple focused light beams obtained by the wavefront sensor 75. In this way, the compensation optical element 72 can correct the wavefront aberration of the return light of the measurement light LS from the test eye E.

[0270] Fig. 15 is a block diagram showing an example of the configuration of a processing system of an ophthalmic apparatus 1a according to the second embodiment. In Fig. 15, the same components as those in Fig. 4 are given the same reference numerals, and the description thereof will be omitted as appropriate.

[0271] The configuration of the processing system of the ophthalmic apparatus 1a according to the second embodiment differs from the configuration of the processing system of the ophthalmic apparatus 1 according to the first embodiment in that the wavefront aberration correction optical system 70 is controlled instead of the VCC lens 47, and a control unit 210a is provided instead of the control unit 210.

[0272] The control unit 210a includes a main control unit 211a and a storage unit 212a. The control unit 210a differs from the control unit 210 in that the control unit 210a controls the wavefront aberration correction optical system 70 instead of the VCC driving unit 47A.

[0273] That is, according to the second embodiment, by controlling the wavefront aberration correction optical system 70, it is possible to change the aberration correction components and change the optical conditions of the optical system.

[0274] The wavefront aberration correction optical system 70 is an example of an "aberration correction device" according to the embodiment. The optical system included in the OCT unit 100, the optical path length changing unit 41, the OCT focusing lens 45, and the wavefront aberration correction optical system 70 (interference optical system) are an example of an "optical system" according to the embodiment.

[0275] <Modification> In the first and second embodiments, the ammonite scan has been described as an example of a scan that combines a low-speed scan and a high-speed scan, but the embodiments are not limited to this.

[0276] FIG. 16 shows an explanatory diagram of an XY scan according to the first embodiment or the first modified example of the second embodiment.

[0277] The XY scan according to the first modification is also a scan mode in which the scan center position of the high-speed scan is moved along the scan pattern (scan trajectory) of the low-speed scan, and one or more high-speed scans are sequentially performed in a scan pattern defined based on the moved scan center position. In the XY scan according to this modification, the high-speed scan is a circle scan, and the low-speed scan is an ellipse scan, and the sequentially performed circle scans are performed so as to intersect with the scan pattern of the immediately preceding circle scan. In other words, the circle scans are sequentially performed so that the scan patterns of two adjacent circle scans intersect.

[0278] In FIG. 16, the low-speed scan pattern Lsc1 is shown diagrammatically, and the high-speed scan pattern HS1 is shown diagrammatically. n (n is an integer equal to or greater than 4), HS1 n-1 , HS1 n-2 , HS1 n-3 is shown diagrammatically.

[0279] Like the ammonite scan, the XY scan combines a low-speed scan and a high-speed scan, allowing simple control to scan the subject's eye E from various scan directions. In particular, it becomes possible to perform high-density scanning around the center of the XY scan (the center position of the low-speed scan), and a wide-angle area including the site of interest can be scanned with simple control.

[0280] According to this modified example, by scanning the subject's eye E with an XY scan, it becomes possible to measure or photograph the subject's eye E with higher image quality and at a wider angle, regardless of the cross-sectional structure of the subject's eye E.

[0281] FIG. 17 shows an explanatory diagram of a three-dimensional vertical (3D(V)) scan according to the second modification of the first embodiment or the second embodiment.

[0282] The 3D (V) scan according to the second modification is also a scan mode in which the scan center position of the high-speed scan is moved along the scan pattern (scan trajectory) of the low-speed scan, and one or more high-speed scans are sequentially performed in a scan pattern defined based on the moved scan center position. In the 3D (V) scan according to this modification, the high-speed scan is a vertical line scan, and the low-speed scan is a horizontal line scan.

[0283] In FIG. 17, the low-speed scan pattern Lsc2 is shown diagrammatically, and the high-speed scan pattern HS2 is shown diagrammatically. n (n is an integer equal to or greater than 4), HS2 n-1 , HS2 n-2 , HS2 n-3 is shown diagrammatically.

[0284] Like the ammonite scan, the 3D(V) scan combines low-speed and high-speed scans, allowing scanning of the subject's eye E from various scanning directions with simple control. In particular, it becomes possible to scan the subject's eye E with uniform density, and a wide-angle area including the area of ​​interest can be scanned with simple control.

[0285] According to this modified example, by scanning the subject's eye E with a 3D (V) scan, it becomes possible to measure or photograph the subject's eye E with higher image quality and at a wider angle, regardless of the cross-sectional structure of the subject's eye E.

[0286] FIG. 18 shows an explanatory diagram of a three-dimensional horizontal (3D(H)) scan according to the third modified example of the first or second embodiment.

[0287] The 3D(H) scan according to the third modification is also a scan mode in which the scan center position of the high-speed scan is moved along the scan pattern (scan trajectory) of the low-speed scan, and one or more high-speed scans are sequentially performed in a scan pattern defined based on the moved scan center position. In the 3D(H) scan according to this modification, the high-speed scan is a horizontal line scan, and the low-speed scan is a vertical line scan.

[0288] In FIG. 18, the low-speed scan pattern Lsc3 is shown diagrammatically, and the high-speed scan pattern HS3 is shown diagrammatically. n (n is an integer equal to or greater than 4), HS3 n-1 , HS3 n-2 , HS3 n-3 is shown diagrammatically.

[0289] Like the ammonite scan, the 3D(H) scan combines low-speed and high-speed scans, allowing scanning of the subject's eye E from various scanning directions with simple control. In particular, it becomes possible to scan the subject's eye E with uniform density, and a wide-angle area including the area of ​​interest can be scanned with simple control.

[0290] According to this modified example, by scanning the subject's eye E with a 3D(H) scan, it becomes possible to measure or photograph the subject's eye E with higher image quality and at a wider angle, regardless of the cross-sectional structure of the subject's eye E.

[0291] [Effect] An OCT device, a control method for the OCT device, and a program according to an embodiment will be described.

[0292] The first aspect of the embodiment is an OCT device (ophthalmic device 1, 1a) including an optical system (an optical system included in the OCT unit 100, an optical path length changing unit 41, an OCT focusing lens 45, and a VCC lens 47 (or a wavefront aberration correction optical system 70), an interference optical system) and a control unit (210, 210a, a main control unit 211, a main control unit 211a). The optical system is configured to be able to change optical conditions (a focusing position of the measurement light LS, a polarization component of the measurement light LS, an aberration correction component, an optical path length difference between the measurement light LS and the reference light LR, or a position of the optical system with respect to the subject's eye E), includes an optical scanner (42), and is configured to acquire OCT data of the subject by scanning the subject (subject's eye E) with the measurement light (LS) using the optical scanner. The control unit controls the optical scanner to scan the subject with the measurement light along the fast scan axis based on a reference position moving along the slow scan axis. The control unit changes the optical conditions in synchronization with the period of the slow scan along the slow scan axis.

[0293] According to this aspect, since the optical conditions of the optical system can be changed in synchronization with the cycle of the slow scan using the OCT data obtained during the scan, it is possible to acquire an image of the object to be measured with good image quality without incurring deterioration of image quality due to the shift of the scan position during the scan, etc. In particular, when the object to be measured is photographed at a wide angle, it is possible to acquire an image of the object to be measured with good image quality without performing a pre-scan.

[0294] In the second aspect of the embodiment, in the first aspect, the optical system includes an interference optical system (the optical system included in the OCT unit 100, the optical path length changer 41, the OCT focusing lens 45, and the VCC lens 47 (or the wavefront aberration correction optical system 70)) and an optical path length difference changer (the optical path length changer 41, or the corner cube 114 and the reference drive unit 114A). The interference optical system splits light (L0) from a light source (light source unit 101) into measurement light and reference light (LR), projects the measurement light that has passed through a measurement optical path in which one or more optical elements (OCT focusing lens 45, the corner cube 114, the optical path length changer 41, the polarization controller 103) are arranged, and detects interference light (LC) between the return light from the object and the reference light that has passed through the reference optical path. The optical path length difference changer changes the difference between the optical path length of the measurement light and the optical path length of the reference light. The control unit changes the optical conditions of the optical system by controlling at least one of the one or more optical elements and the optical path length difference changing member.

[0295] According to this aspect, the OCT is performed on the object by changing the optical conditions of the optical system by controlling at least one of the one or more optical elements and the optical path length difference changing member, thereby making it possible to acquire an image of the object with good image quality regardless of the cross-sectional shape of the object.

[0296] In a third aspect of the embodiment, in the second aspect, the one or more optical elements include a focusing lens (OCT focusing lens 45) or an aberration correction device (VCC lens 47 or wavefront aberration correction optical system 70).

[0297] According to this aspect, by controlling at least one of the optical elements including the focusing lens or the aberration correction device and the optical path length difference changing member, the optical conditions of the optical system are changed without performing a pre-scan, and OCT is performed on the object to be measured. As a result, an image of the object to be measured can be obtained with good image quality regardless of the cross-sectional shape of the object to be measured, and the measurement time (imaging time) can be shortened.

[0298] A fourth aspect of the embodiment is the second or third aspect, and further includes an image forming unit (220) and an image quality evaluation value calculation unit (232B). The image forming unit forms an image of the object to be measured based on the OCT data. The image quality evaluation value calculation unit calculates an evaluation value of the image quality of the image of the object to be measured. The control unit controls one or more optical elements based on the evaluation value.

[0299] According to this aspect, the optical conditions of the optical system are changed based on the evaluation value of the image quality of the image of the object to be measured, so that an image of the object to be measured can be obtained with good image quality through simple control and with high accuracy, regardless of the cross-sectional shape of the object to be measured.

[0300] A fifth aspect of the embodiment is any of the first to third aspects, further comprising a movement mechanism (150) for relatively moving the optical system with respect to the object to be measured. The control unit changes the optical conditions of the optical system by controlling the movement mechanism.

[0301] According to this aspect, the optical system is moved relative to the object to be measured, thereby changing the optical conditions of the optical system and executing OCT on the object to be measured. As a result, an image of the object to be measured can be acquired with good image quality regardless of the cross-sectional shape of the object to be measured, and the measurement time (photographing time) can be shortened.

[0302] A sixth aspect of the embodiment is the second or third aspect, further including an image forming unit (220). The image forming unit forms an image of the object to be measured based on the OCT data. The control unit controls the optical path length difference changing member based on the position of the object to be measured in the image.

[0303] According to this aspect, the optical path length difference between the measurement light and the reference light is changed in synchronization with the period of the slow scan using the OCT data obtained during the scan, so that an image of the object to be measured can be obtained with good image quality.

[0304] In a seventh aspect of the embodiment, in any one of the first to third aspects, the fast scan axis is a circular scan axis, and the slow scan axis is a spiral scan axis.

[0305] According to this embodiment, it is possible to scan the area near the center (the center position of the slow scan) at a high density in a short period of time, and scan at a low density over a longer period of time as the area moves away from the center. This makes it possible to obtain an image of the object to be measured with good image quality in a wide-angle area including the area of ​​interest with simple control.

[0306] An eighth aspect of the embodiment is a control method for an OCT device (ophthalmic device 1, 1a) including an optical system (an optical system included in an OCT unit 100, an optical path length changing unit 41, an OCT focusing lens 45, and a VCC lens 47 (or a wavefront aberration correction optical system 70), and an interference optical system) configured to change optical conditions (a focal position of the measurement light LS, a polarization component of the measurement light LS, an aberration correction component, an optical path length difference between the measurement light LS and the reference light LR, or a position of the optical system with respect to the eye E), including an optical scanner (42), and configured to acquire OCT data of the object to be measured by scanning the object to be measured (the eye E) with the measurement light (LS) using the optical scanner. The control method for the OCT device includes a control step and an optical condition changing step. The control step controls the optical scanner so that the object to be measured is scanned with the measurement light along the fast scan axis based on a reference position that moves along the slow scan axis. The optical condition changing step changes the optical conditions in synchronization with the period of the slow scan along the slow scan axis.

[0307] According to this aspect, since the optical conditions of the optical system can be changed in synchronization with the cycle of the slow scan using the OCT data obtained during the scan, it is possible to acquire an image of the object to be measured with good image quality without incurring deterioration of image quality due to the shift of the scan position during the scan, etc. In particular, when the object to be measured is photographed at a wide angle, it is possible to acquire an image of the object to be measured with good image quality without performing a pre-scan.

[0308] In the ninth aspect of the embodiment, in the eighth aspect, the optical system includes an interference optical system (the optical system included in the OCT unit 100, the optical path length changer 41, the OCT focusing lens 45, and the VCC lens 47 (or the wavefront aberration correction optical system 70)) and an optical path length difference changer (the optical path length changer 41, or the corner cube 114 and the reference drive unit 114A). The interference optical system splits light (L0) from a light source (light source unit 101) into measurement light and reference light (LR), projects the measurement light that has passed through a measurement optical path in which one or more optical elements (OCT focusing lens 45, the corner cube 114, the optical path length changer 41, the polarization controller 103) are arranged, and detects interference light (LC) between the return light from the object and the reference light that has passed through the reference optical path. The optical path length difference changer changes the difference between the optical path length of the measurement light and the optical path length of the reference light. The optical condition changing step changes the optical condition of the optical system by controlling at least one of one or more optical elements and an optical path length difference changing member.

[0309] According to this aspect, the OCT is performed on the object by changing the optical conditions of the optical system by controlling at least one of the one or more optical elements and the optical path length difference changing member, thereby making it possible to acquire an image of the object with good image quality regardless of the cross-sectional shape of the object.

[0310] In a tenth aspect of the embodiment, in the ninth aspect, the one or more optical elements include a focusing lens (OCT focusing lens 45) or an aberration correction device (VCC lens 47 or wavefront aberration correction optical system 70).

[0311] According to this aspect, by controlling at least one of the optical elements including the focusing lens or the aberration correction device and the optical path length difference changing member, the optical conditions of the optical system are changed without performing a pre-scan, and OCT is performed on the object to be measured. As a result, an image of the object to be measured can be obtained with good image quality regardless of the cross-sectional shape of the object to be measured, and the measurement time (imaging time) can be shortened.

[0312] An eleventh aspect of the embodiment is the ninth or tenth aspect, and includes an image forming step and an image quality evaluation value calculation step. The image forming step forms an image of the object to be measured based on the OCT data. The image quality evaluation value calculation step calculates an evaluation value of the image quality of the image of the object to be measured. The optical condition changing step controls one or more optical elements based on the evaluation value.

[0313] According to this aspect, the optical conditions of the optical system are changed based on the evaluation value of the image quality of the image of the object to be measured, so that an image of the object to be measured can be obtained with good image quality through simple control and with high accuracy, regardless of the cross-sectional shape of the object to be measured.

[0314] In a twelfth aspect of the embodiment, in any one of the eighth to tenth aspects, the OCT device includes a moving mechanism (150) that moves the optical system relatively to the object to be measured. The optical condition changing step changes the optical condition of the optical system by controlling the moving mechanism.

[0315] According to this aspect, the optical system is moved relative to the object to be measured, thereby changing the optical conditions of the optical system and executing OCT on the object to be measured. As a result, an image of the object to be measured can be acquired with good image quality regardless of the cross-sectional shape of the object to be measured, and the measurement time (photographing time) can be shortened.

[0316] A thirteenth aspect of the embodiment is the ninth or tenth aspect, further comprising an image forming step of forming an image of the object to be measured based on the OCT data. The optical condition changing step controls the optical path length difference changing member based on a position of the object to be measured in the image.

[0317] According to this aspect, the optical path length difference between the measurement light and the reference light is changed in synchronization with the period of the slow scan using the OCT data obtained during the scan, so that an image of the object to be measured can be obtained with good image quality.

[0318] In a fourteenth aspect of the embodiment, in any one of the eighth to tenth aspects, the fast scan axis is a circular scan axis, and the slow scan axis is a spiral scan axis.

[0319] According to this embodiment, it is possible to scan the area near the center (the center position of the slow scan) at a high density in a short period of time, and scan at a low density over a longer period of time as the area moves away from the center. This makes it possible to obtain an image of the object to be measured with good image quality in a wide-angle area including the area of ​​interest with simple control.

[0320] A fifteenth aspect of the embodiment is a program for causing a computer to execute each step of the control method for an OCT apparatus according to any one of the eighth to tenth aspects.

[0321] According to this aspect, since the optical conditions of the optical system can be changed in synchronization with the cycle of the slow scan using the OCT data obtained during the scan, it is possible to acquire an image of the object to be measured with good image quality without incurring deterioration of image quality due to the shift of the scan position during the scan, etc. In particular, when the object to be measured is photographed at a wide angle, it is possible to acquire an image of the object to be measured with good image quality without performing a pre-scan.

[0322] The configuration described above is merely one example for suitably implementing the present invention. Therefore, any modification (omission, substitution, addition, etc.) can be appropriately made within the scope of the gist of the present invention. The configuration to be applied is selected, for example, depending on the purpose. Furthermore, depending on the configuration to be applied, the effects that are obvious to those skilled in the art or the effects described in this specification can be obtained. [Explanation of symbols]

[0323] 1, 1a Ophthalmological equipment 3 Display device 41 Optical path length change unit 45 OCT focusing lens 47 VCC Lens 47A VCC driver 70 Wavefront aberration correction optical system 100 OCT units 103, 118 Polarization Controller 114 Corner Cube 114A Reference Drive 200, 200a Calculation and control unit 210, 210a Control unit 211, 211a Main control unit 212, 212a Storage section 220 Image forming section 230 Data Processing Unit 231 Image synthesis unit 232 Analysis Department 232A Image position identification section 232B Image quality evaluation value calculation unit 240A display section E. Examined eye SAR1 central region SAR2 intermediate area SAR3 Surrounding Area LC interference light LR reference light LS measurement light

Claims

1. an optical system configured to be able to change optical conditions, including an optical scanner, and configured to acquire optical coherence tomography data of an object to be measured by scanning the object to be measured with measurement light using the optical scanner; a control unit that controls the optical scanner to scan the object with the measurement light along a fast scan axis with respect to a reference position that moves along a slow scan axis; Including, An optical coherence tomography device, wherein the control unit changes the optical conditions in synchronization with a period of a slow scan along the slow scan axis.

2. The optical system includes: an interference optical system that splits light from a light source into the measurement light and a reference light, projects the measurement light that has passed through a measurement optical path in which one or more optical elements are arranged onto the object to be measured, and detects interference light between return light from the object to be measured and the reference light that has passed through the reference optical path; an optical path length difference changing member that changes a difference between an optical path length of the measurement light and an optical path length of the reference light; Including, The control unit changes an optical condition of the optical system by controlling at least one of the one or more optical elements and the optical path length difference changing member.

2. An optical coherence tomography apparatus according to claim 1 .

3. The one or more optical elements may include a focusing lens or an aberration correction device.

3. An optical coherence tomography apparatus according to claim 2.

4. an image forming unit that forms an image of the object based on the optical coherence tomography data; an image quality evaluation value calculation unit that calculates an evaluation value of an image quality of the image of the object to be measured; Including, The control unit controls the one or more optical elements based on the evaluation value.

4. An optical coherence tomography apparatus according to claim 2 or 3.

5. a moving mechanism for moving the optical system relatively to the object to be measured, The control unit changes the optical condition of the optical system by controlling the moving mechanism.

4. An optical coherence tomography apparatus according to claim 1, wherein the optical coherence tomography apparatus comprises:

6. an image forming unit that forms an image of the object to be measured based on the optical coherence tomography data; The control unit controls the optical path length difference changing member based on a position of the object to be measured in the image.

4. An optical coherence tomography apparatus according to claim 2 or 3.

7. the fast scan axis is a circular scan axis; The slow scan axis is a helical scan axis.

4. An optical coherence tomography apparatus according to claim 1, wherein the optical coherence tomography apparatus comprises:

8. A method for controlling an optical coherence tomography device including an optical system configured to be able to change optical conditions, including an optical scanner, and configured to acquire optical coherence tomography data of a measurement object by scanning the measurement object with measurement light using the optical scanner, comprising: a control step of controlling the optical scanner to scan the object with the measurement light along a fast scan axis with respect to a reference position that moves along a slow scan axis; an optical condition changing step of changing the optical condition in synchronization with a period of the slow scan along the slow scan axis; A method for controlling an optical coherence tomography apparatus, comprising:

9. The optical system includes: an interference optical system that splits light from a light source into the measurement light and a reference light, projects the measurement light that has passed through a measurement optical path in which one or more optical elements are arranged onto the object to be measured, and detects interference light between return light from the object to be measured and the reference light that has passed through the reference optical path; an optical path length difference changing member that changes a difference between an optical path length of the measurement light and an optical path length of the reference light; Including, The optical condition changing step changes the optical condition of the optical system by controlling at least one of the one or more optical elements and the optical path length difference changing member. The method for controlling an optical coherence tomography apparatus according to claim 8 .

10. The one or more optical elements may include a focusing lens or an aberration correction device. The method for controlling an optical coherence tomography apparatus according to claim 9 .

11. an image forming step of forming an image of the object based on the optical coherence tomography data; an image quality evaluation value calculation step of calculating an evaluation value of image quality of the image of the object to be measured; Including, The optical condition changing step controls the one or more optical elements based on the evaluation value.

11. The method for controlling an optical coherence tomography apparatus according to claim 9 or 10.

12. the optical coherence tomography apparatus includes a moving mechanism that moves the optical system relatively to the object to be measured, The optical condition changing step changes the optical condition of the optical system by controlling the moving mechanism. A method for controlling an optical coherence tomography apparatus according to any one of claims 8 to 10.

13. an image forming step of forming an image of the object based on the optical coherence tomography data; The optical condition changing step includes controlling the optical path length difference changing member based on a position of the object to be measured in the image.

11. The method for controlling an optical coherence tomography apparatus according to claim 9 or 10.

14. the fast scan axis is a circular scan axis; The slow scan axis is a helical scan axis. A method for controlling an optical coherence tomography apparatus according to any one of claims 8 to 10.

15. A program for causing a computer to execute each step of the method for controlling an optical coherence tomography apparatus according to any one of claims 8 to 10.

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