Optical coherence tomography device, control method therefor, and program

Abstract

An optical coherence tomography apparatus includes an optical system and a control unit. The optical system is configured so as to be capable of changing optical conditions, includes an optical scanner, and is configured so as to acquire optical coherence tomography data of an object to be measured by scanning the object with measurement light using the optical scanner. The control unit controls the optical scanner so as to scan the object to be measured along the high-speed scanning axis with the reference position moved along the low-speed scanning axis as reference measurement light. The control unit changes the optical condition in synchronization with the period of low-speed scanning along the low-speed scanning axis.

Description

Technical Field

[0001] This invention relates to an optical coherence tomography (OCT) device, a control method for the OCT device, and a program. Background Technology

[0002] Optical coherence tomography (OCT) devices are known to use light beams from sources such as lasers to form images representing the surface and internal morphology of the object being measured. Since OCT is non-invasive and can be performed on biological organisms, its applications in the medical and biological fields are highly anticipated. For example, in ophthalmology, devices for forming images of the fundus and cornea are already in practical use. Devices employing such OCT methods (OCT devices) can be used for observation of various parts of the examined eye. Furthermore, due to the ability to acquire high-resolution images, they are used for the diagnosis of various ophthalmic diseases.

[0003] When photographing an object with a wide-angle lens, the optimal optical conditions for the optical system at each shooting location (scanning area) vary depending on the cross-sectional shape of the object. As a result, sometimes the image quality around the area of ​​interest is insufficient, requiring a re-photograph of the object.

[0004] To address this, one could consider expanding the depth-direction imaging range (measurement range, depth range) of OCT. However, the depth-direction imaging range of OCT is limited. Expanding the depth-direction imaging range would lead to increased costs for the detection system and larger optical systems.

[0005] For example, Patent Document 1 discloses a method for performing a pre-scan, which involves adjusting the optical path length of a reference light based on A-scan images at multiple locations along the scanning direction of a pre-acquired B-scan, so that the tomographic image of the observed part is positioned at the optimal location within the B-scan image.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-16151 Summary of the Invention However, in Patent Document 1, a pre-scan is required before the formal scan, which increases the imaging time (measurement time). When the object being measured is a living eye, this increases the burden on the examinee.

[0007] The present invention was made in view of the following circumstances, and one of its objects is to provide a new technique for acquiring an image of the object being measured with good image quality when shooting the object with a wide angle.

[0008] One embodiment is an optical coherence tomography (OCT) apparatus, comprising: an optical system configured to change optical conditions, including a light scanner configured to acquire OCT data of the test object by scanning the test object with measurement light using the light scanner; and a control unit that controls the light scanner to scan the test object along a high-speed scanning axis with the measurement light using a reference position moved along a low-speed scanning axis as a reference, wherein the control unit changes the optical conditions synchronously with the period of the low-speed scanning along the low-speed scanning axis.

[0009] Another embodiment is a control method for an optical coherence tomography (OCT) apparatus, the OCT apparatus including an optical system configured to change optical conditions, and including a light scanner configured to acquire OCT data of the test object by scanning the test object with measurement light using the light scanner. The control method for the OCT apparatus includes: a control step of controlling the light scanner to scan the test object along a high-speed scanning axis with the measurement light using a reference position moved along a low-speed scanning axis as a reference; and an optical condition changing step of changing the optical conditions synchronously with the period of the low-speed scanning along the low-speed scanning axis.

[0010] Another aspect of some implementations is a program that causes a computer to execute the steps of the control method for the optical coherence tomography apparatus described above.

[0011] Another embodiment is a computer program product including a computer program / instructions. When the computer program / instructions are executed by a processor, the computer program product implements the steps of the control method for the optical coherence tomography (OCT) device described above.

[0012] Another embodiment is a computer-readable storage medium (recording medium) storing a computer program / instructions. When the computer program / instructions are executed by a processor, the computer-readable storage medium implements the steps of the control method for the optical coherence tomography (OCT) device described above.

[0013] According to embodiments of the present invention, a new technique can be provided for acquiring an image of the object being measured with good image quality when shooting the object with a wide-angle lens. Attached Figure Description

[0014] Figure 1 This is a schematic diagram illustrating an example of the optical system structure of the ophthalmic device according to the first embodiment.

[0015] Figure 2 This is a schematic diagram illustrating an example of the optical system structure of the ophthalmic device according to the first embodiment.

[0016] Figure 3 This is a schematic diagram illustrating an example of the optical system structure of the ophthalmic device according to the first embodiment.

[0017] Figure 4 This is a schematic diagram illustrating an example of the processing system structure of the ophthalmic device according to the first embodiment.

[0018] Figure 5 This is a schematic diagram illustrating an example of the processing system structure of the ophthalmic device according to the first embodiment.

[0019] Figure 6 This is a diagram illustrating the operation of the ophthalmic device according to the first embodiment.

[0020] Figure 7 This is a diagram illustrating the operation of the ophthalmic device according to the first embodiment.

[0021] Figure 8 This is a diagram illustrating the operation of the ophthalmic device according to the first embodiment.

[0022] Figure 9 This is a diagram illustrating the operation of the ophthalmic device according to the first embodiment.

[0023] Figure 10 This is a diagram illustrating the operation of the ophthalmic device according to the first embodiment.

[0024] Figure 11 This is a diagram illustrating the operation of the ophthalmic device according to the first embodiment.

[0025] Figure 12A This is a flowchart illustrating an example of the operation of the ophthalmic device according to the first embodiment.

[0026] Figure 12B This is a flowchart illustrating an example of the operation of the ophthalmic device according to the first embodiment.

[0027] Figure 13A This is a flowchart illustrating an example of the operation of the ophthalmic device according to the first embodiment.

[0028] Figure 13B This is a flowchart illustrating an example of the operation of the ophthalmic device according to the first embodiment.

[0029] Figure 14 This is a schematic diagram illustrating an example of the optical system structure of the ophthalmic device according to the second embodiment.

[0030] Figure 15 This is a schematic diagram illustrating an example of the processing system structure of the ophthalmic device according to the second embodiment.

[0031] Figure 16 This is an explanatory diagram of the operation of an ophthalmic device according to a first embodiment or a first modification of the second embodiment.

[0032] Figure 17 This is an explanatory diagram of the operation of an ophthalmic device according to a second variation of the first or second embodiment.

[0033] Figure 18 This is an explanatory diagram of the operation of an ophthalmic device according to a third variation of the first or second embodiment. Detailed Implementation

[0034] Examples of embodiments of the optical coherence tomography (OCT) apparatus, its control method, and its procedure according to the present invention will be described in detail with reference to the accompanying drawings. Furthermore, the contents of documents cited in this specification and any prior art can be incorporated into the following embodiments.

[0035] The optical coherence tomography (OCT) apparatus of this embodiment includes an optical system configured to modify optical conditions. The optical system includes a light scanner, which scans the object under test using measurement light used in OCT to acquire OCT data of the object. The OCT apparatus also includes a control unit that controls the light scanner to scan the object under test using measurement light in a single scan, combining a low-speed scan along a low-speed scan axis with a high-speed scan along a high-speed scan axis. Specifically, the control unit controls the light scanner to scan the object under test using measurement light along the high-speed scan axis, using a reference position of the high-speed scan moving along the low-speed scan axis as a reference. Furthermore, during the scanning (image capture, measurement) process, the control unit modifies the optical conditions of the optical system synchronously with the period of the low-speed scan along the low-speed scan axis.

[0036] Such an OCT device, when performing a first high-speed scan in a single scan process combining low-speed and high-speed scans, can synchronously change the optical conditions of the optical system with the period of the low-speed scan based on OCT data obtained through a second high-speed scan performed before the first high-speed scan. In some embodiments, the optical conditions of the optical system are fixed during the high-speed scan.

[0037] In some embodiments, the control unit changes the optical conditions based on OCT data obtained from a high-speed scan (or A-scan) performed before a high-speed scan (or A-scan) in which the optical conditions of the optical system are changed during the scanning process, or on an OCT image formed based on such OCT data. Examples of high-speed scans performed before a high-speed scan in which the optical conditions of the optical system are changed include high-speed scans performed before a first high-speed scan in which the optical conditions of the optical system are changed, and high-speed scans 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 being measured based on OCT data or an OCT image obtained from a high-speed scan performed before the first high-speed scan position (region), and based on the estimated cross-sectional structure, changes the optical conditions of the optical system synchronously with the period of the low-speed scan. The OCT device performs a high-speed scan at a second high-speed scan position, which is different from the first high-speed scan position and moves along the low-speed scan axis.

[0038] In some implementations, a single scan is a combination of one low-speed scan (which may be more than one) and two or more high-speed scans performed during the period from a predetermined scan start time to a predetermined scan end time. In some implementations, a single scan is a scan performed from a predetermined scan start position to a predetermined scan end position.

[0039] In some implementations, the OCT apparatus, during scanning of each of a plurality of scanning regions defined relative to the object being measured, modulates the optical conditions of the optical system for each scanning region in sync with the period of the low-speed scan along the low-speed scan axis. For example, the OCT apparatus substantially estimates the cross-sectional structure of the object being measured for each scanning region based on OCT data or OCT images obtained through previously performed high-speed scans, and modulates the optical conditions of the optical system in sync with the period of the low-speed scan based on the estimated cross-sectional structure.

[0040] Examples of optical conditions for an optical system include the amount of light used for measurement in OCT, beam diameter, focus position, polarization component of the measurement light, aberration correction component, difference in optical path length between the measurement light and the reference light, and the position of the optical system relative to the object being measured.

[0041] Low-speed scanning can be defined by any one-dimensional or two-dimensional scanning pattern. High-speed scanning can also be defined by any one-dimensional or two-dimensional scanning pattern. Examples of such low-speed or high-speed scanning include line scanning, cross scanning, circular scanning, radial scanning, concentric circle scanning, multi-line intersecting scanning, spiral scanning (Spiralscan), and Lissajous scanning. Furthermore, as an example of combining low-speed and high-speed scanning, three-dimensional scanning such as ammonite scanning is also included. Ammonite scanning is performed by combining low-speed scanning with a spiral scanning axis and high-speed scanning with a circular scanning axis.

[0042] Therefore, when photographing the object being measured with a wide-angle lens, it is possible to acquire an image of the object with good image quality without performing a pre-scan.

[0043] In some embodiments, the optical system includes one or more optical elements, and by controlling one or more optical elements, at least one of the following can be changed: the focus position of the measurement light used for OCT, the polarization component of the measurement light, the aberration correction component, and the difference in optical path length between the measurement light and the reference light.

[0044] In some embodiments, the optical system includes a mechanism for moving the optical system or one or more optical elements, which, when controlled, allows for the modification of any one of the following: the focus position of the measurement light used in OCT, the polarization component of the measurement light, the aberration correction component, and the difference in optical path length between the measurement light and the reference light.

[0045] In some embodiments, the OCT device includes a movement mechanism that moves the optical system relative to the object being measured, and by controlling the movement mechanism, the position of the optical system relative to the object being measured can be changed.

[0046] The focus position is changed by a focus position changing component, which is an optical element. Examples of focus position changing components include lenses that can move along the optical axis, liquid crystal lenses, Alvarez lenses, etc.

[0047] The polarization component is changed by a polarization component changing component, which is an optical element. Examples of polarization components include a polarization controller. When light from a light source is split into a measurement light and a reference light for OCT, the polarization controller can change the polarization component of either the light from the light source or the measurement light.

[0048] The aberration correction component is changed by the aberration correction device, which is an optical element. Examples of aberration correction devices include a variable cross cylinder (VCC) lens, a liquid crystal lens, a wavefront aberration correction optical system including a deformable mirror, and an Alvarez lens.

[0049] The difference in optical path length is changed by an optical path length changing component, which is an optical element or mechanism. Examples of optical path length changing components include those that change at least one of the optical path length of the measuring light and the optical path length of the reference light.

[0050] The position of the optical system relative to the object being measured is changed by a mechanism that alters at least one of the object being measured and the optical system. Examples of such mechanisms include a moving mechanism that changes the relative position of the object being measured and a holding member that maintains the optical system.

[0051] In some embodiments, the optical system includes an interferometric optical system and a path length difference changing component. The interferometric optical system is configured to split light from a light source into a measurement light and a reference light; project the measurement light, which has passed through a measurement path equipped with one or more optical elements, onto the object being measured; and detect the interference between the return light from the object being measured and the reference light that has passed through the reference path. The path length difference changing component changes the difference between the path length of the measurement light and the 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 path length difference changing component.

[0052] In some embodiments, the OCT apparatus includes: an image forming unit that forms an image of the object to be measured based on OCT data; and an image quality evaluation value calculation unit that calculates an image quality evaluation value of the image of the object to be measured. A control unit controls one or more of the aforementioned optical elements based on the calculated evaluation value.

[0053] For example, the control unit controls one or more optical elements based on calculated evaluation values ​​to ensure that the image of the object being measured is at or above a predetermined image quality level. Examples of image quality exceeding the predetermined image quality level include: an image quality where the overall image quality evaluation value is the highest; an image quality where the overall image quality evaluation value is at or above a predetermined threshold level; an image quality where the statistical value of the image quality evaluation values ​​of multiple images calculated for each scan area is the highest; and an image quality where the statistical value of the image quality evaluation values ​​of multiple images calculated for each scan area is at or above a predetermined threshold level. Examples of statistical values ​​include: maximum value, minimum value, median, mean, mode, range, variance, standard deviation, a weighted average with a larger weighting coefficient closer to the area of ​​interest (optical axis of the optical system), or a value using a predetermined evaluation formula for any of the above statistical values.

[0054] In some embodiments, the OCT device includes a movement mechanism that moves the optical system relative to the object being measured. The control unit changes the optical conditions of the optical system by controlling the movement mechanism.

[0055] In some embodiments, the OCT device includes the image forming unit described above. The control unit controls the optical path length difference changing unit based on the position of the object to be measured in the image.

[0056] In some embodiments, the scanning area includes: a central region of the object being measured, including the optical axis of the optical system; and one or more peripheral regions surrounding the central region. For example, one or more peripheral regions include: one or more intermediate regions disposed outside the central region and surrounding the central region; and a peripheral region disposed outside the outermost intermediate region of the one or more intermediate regions and surrounding the outermost intermediate region.

[0057] Therefore, even when the inclination of the cross section differs in the central region and one or more peripheral regions of the object being measured, images of the object being measured can be acquired with good image quality.

[0058] The control method of the OCT device in the embodiment is a method for controlling the OCT device of the embodiment. The control method of the OCT device in the embodiment includes one or more steps executed by the OCT device. The program (computer program) / instructions of the embodiment cause a computer to execute each step of the control method of the OCT device of the embodiment. The computer program product of the embodiment includes a computer program / instructions. When the computer program / instructions are executed by a processor, the computer program product implements each step of the control method of the OCT device of the embodiment. The recording medium (storage medium) of the embodiment is any computer-readable, non-transitory recording medium that records (stores) the program of the embodiment. The computer-readable storage medium of the embodiment stores the computer program / instructions. When the computer-readable storage medium is executed by a processor, the computer-readable storage medium implements each step of the control method of the OCT device of the embodiment. The recording medium can be an electronic medium utilizing magnetism, light, opto-magnetism, semiconductors, etc. Typically, the recording medium is magnetic tape, magnetic disk, optical disk, optical disk, flash memory, solid-state drive, etc. Alternatively, the program can be transmitted and received via a network such as the Internet or LAN.

[0059] Hereinafter, an ophthalmic device that uses a living eye as the object of measurement will be described as an example of an OCT device as an embodiment. However, the embodiment can also be applied to OCT devices that use objects other than a living eye as the object of measurement.

[0060] The ophthalmic device described in this embodiment can perform OCT on any part of the examined eye, such as the fundus or anterior eye. In this specification, images acquired by OCT are sometimes collectively referred to as OCT images. In addition, the measurement work used to form OCT images is sometimes referred to as OCT measurement (formal measurement, predictive measurement).

[0061] Hereinafter, in the embodiments, the use of OCT methods with a swept-frequency source type in OCT measurements or imaging will be described in particular detail. However, the structure of the embodiments can also be applied to ophthalmic devices using other types of OCT (e.g., spectral domain type or time domain type).

[0062] In addition, the following evaluation values ​​for image quality explain the situation where the higher the image quality, the higher the value, and the lower the image quality, the lower the evaluation value. However, the implementation method can also be applied to the situation where the higher the image quality, the lower the value, and the lower the image quality, the higher the evaluation value.

[0063] <First Implementation> [structure] like Figures 1-3 As shown, the ophthalmic device 1 of the first embodiment includes a fundus camera unit 2, an OCT unit 100, and a computation control unit 200. The fundus camera unit 2 has an optical system that is substantially the same as that of a conventional fundus camera. The OCT unit 100 is provided with an optical system for acquiring OCT images (e.g., tomographic images) of the fundus (or anterior eye). The computation control unit 200 includes a computer that performs various computational processing, control processing, etc.

[0064] [Fundus camera unit 2] exist Figure 1 The fundus camera unit 2 shown is equipped with an optical system for acquiring a two-dimensional image (fundus image) representing the surface morphology of the fundus Ef of the examined eye E. Fundus images include observation images and captured images. Observation images are, for example, monochrome video images formed using near-infrared light at a predetermined frame rate. Captured images can be, for example, color images obtained by flash emission of visible light or monochrome static images using near-infrared or visible light as illumination. The fundus camera unit 2 can also be configured to acquire images other than these, such as sodium fluorescein fluorescence images, indocyanine green fluorescence images, autofluorescence images, etc.

[0065] The fundus camera unit 2 is equipped with a jaw rest and a forehead protector to support the subject's face. Furthermore, the fundus camera unit 2 includes an illumination optical system 10 and an imaging optical system 30. The illumination optical system 10 illuminates the fundus (Ef) with light. The imaging optical system 30 guides the fundus-reflected light of this illumination to the imaging device (CCD image sensor (sometimes simply referred to as CCD) 35, 38). Additionally, the imaging optical system 30 guides measurement light from the OCT unit 100 to the fundus (Ef) and guides the measurement light that has passed through the fundus (Ef) to the OCT unit 100.

[0066] The observation light source 11 of the illumination optical system 10 includes, for example, a halogen lamp. Light output from the observation light source 11 (observation illumination light) is reflected by a mirror 12 with a curved reflective surface, passes through a condenser lens 13, and becomes near-infrared light after passing through a visible light cutoff filter 14. Furthermore, the observation illumination light temporarily converges near the imaging light source 15, is reflected by a mirror 16, and passes through relay lenses 17 and 18, an aperture 19, and a relay lens 20. Then, the observation illumination light is reflected by the peripheral portion (the area around the aperture) of the aperture lens 21, passes through a dichroic mirror 48, and is refracted by the objective lens 22 to illuminate the fundus (Ef). Alternatively, an LED (Light Emitting Diode) can also be used as the observation light source.

[0067] The fundus reflected light from the illumination is refracted by objective lens 22, passes through dichroic mirror 48, passes through the aperture formed in the central region of aperture lens 21, passes through dichroic mirror 55, passes through focusing lens 31, and is reflected by mirror 32. Furthermore, this fundus reflected light passes through semi-reflective mirror 33A, is reflected by dichroic mirror 33, and is imaged onto the light-receiving surface of CCD image sensor 35 by condenser lens 34. CCD image sensor 35 detects fundus reflected light, for example, at a predetermined frame rate. An image (observation image) based on the fundus reflected light detected by CCD image sensor 35 is displayed on display device 3. Additionally, when the focus of imaging optical system 30 is aligned with the anterior eye, an observation image of the anterior eye of the examined eye E is displayed.

[0068] The imaging light source 15 includes, for example, a xenon lamp. Light output from the imaging light source 15 (imaging illumination light) illuminates the fundus Ef through the same path as the observation illumination light. The fundus-reflected light from the imaging illumination light is guided to a dichroic mirror 33 through the same path as the observation illumination light, passes through the dichroic mirror 33, is reflected by a reflecting mirror 36, and is imaged onto the light-receiving surface of a CCD image sensor 38 by a condenser lens 37. An image (imported image) based on the fundus-reflected light detected by the CCD image sensor 38 is displayed on the display device 3. Furthermore, the display device 3 displaying the observation image and the display device 3 displaying the captured image can be the same device or different devices. Additionally, when the same imaging is performed with infrared light illuminating the examined eye E, an infrared captured image is displayed. Alternatively, an LED can also be used as the imaging light source.

[0069] The LCD (Liquid Crystal Display) 39 displays fixation targets and visual acuity testing targets. Fixation targets are used to cause the tested eye E to fixate, and are used during fundus photography and OCT measurements.

[0070] A portion of the light output from LCD39 is reflected by semi-reflective mirror 33A and then by reflective mirror 32. It then passes through focusing lens 31 and dichroic mirror 55, and through the aperture of aperture lens 21. The light passing through the aperture is then refracted by dichroic mirror 48, refracted by objective lens 22, and projected onto the fundus Ef.

[0071] By changing the display position of the fixation target on the LCD39 screen, the fixation position of the examined eye E can be changed. The fixation position of the examined eye E may include, for example, a position for acquiring an image centered on the macula of the fundus Ef, a position for acquiring an image centered on the optic nerve head, or a position for acquiring an image centered on the center of the fundus between the macula and the optic nerve head. Furthermore, the display position of the fixation target can be changed arbitrarily.

[0072] Furthermore, similar to conventional fundus cameras, the fundus camera unit 2 is equipped with an alignment optical system 50 and a focusing optical system 60. The alignment optical system 50 generates a target (alignment target) for aligning the device optical system with respect to the examined eye E. The focusing optical system 60 generates a target (split-image target) for focusing with respect to the fundus Ef.

[0073] The light (alignment light) output from LED51 of the alignment optical system 50 passes through apertures 52 and 53 and relay lens 54, is reflected by dichroic mirror 55, and passes through the aperture of aperture lens 21. The light passing through the aperture passes through dichroic mirror 48 and is projected onto the cornea of ​​the eye being examined, E, by objective lens 22.

[0074] The corneal reflected light from the alignment light passes through the objective lens 22, the dichroic mirror 48, and the aforementioned aperture. A portion of it passes through the dichroic mirror 55, then through the focusing lens 31, is reflected by the reflecting mirror 32, and passes through the semi-reflective mirror 33A. The corneal reflected light that has passed through the semi-reflective mirror 33A is reflected by the dichroic mirror 33 and projected by the condenser lens 34 onto the light-receiving surface of the CCD image sensor 35. The light-receiving image (aligned target) based on the CCD image sensor 35 is displayed on the display device 3 along with the observed image. The user performs the same operation as with conventional fundus cameras to perform alignment. Alternatively, the arithmetic control unit 200 can analyze the position of the aligned target and move the optical system to perform alignment (automatic alignment function).

[0075] During focusing adjustment, the reflective surface of the reflector 67 is tilted and positioned in the optical path of the illumination optics system 10. The light (focused light) output from the LED 61 of the focusing optics system 60 passes through the relay lens 62, is split into two beams by the split-image target plate 63, passes through the two-aperture aperture 64, and is reflected by the reflector 65. The light reflected by the reflector 65 is temporarily imaged onto the reflective surface of the reflector 67 by the condenser lens 66 and then reflected. Subsequently, the focused light passes through the relay lens 20, is reflected by the aperture lens 21, passes through the dichroic mirror 48, is refracted by the objective lens 22, and is projected onto the fundus Ef.

[0076] The fundus reflection of the focused light travels the same path as the corneal reflection of the aligned light and is detected by the CCD image sensor 35. The light-receiving image (split-image target) formed by the CCD image sensor 35 is displayed on the display device 3 along with the observed image. As before, the arithmetic control unit 200 analyzes the position of the split-image target and moves the focusing lens 31 and the focusing optical system 60 to perform focusing (autofocus function). Alternatively, focusing can be performed manually while visually confirming the split-image target.

[0077] The dichroic mirror 48 branches the optical path used for OCT measurement from the optical path used for fundus imaging. The dichroic mirror 48 reflects the light used for OCT measurement in the wavelength range, allowing the light used for fundus imaging to pass through. In the optical path used for OCT measurement, from the OCT unit 100 side, a collimating lens unit 40, an optical path length changing unit 41, an optical scanner 42, a collimating lens 43, a reflecting mirror 44, an OCT focusing lens 45, a field lens 46, and a VCC lens 47 are arranged sequentially.

[0078] The optical path length changing unit 41 is configured to be able to Figure 1 Moving the optical path in the direction of the arrow indicates changes the optical path length for OCT measurement. This change in optical path length is used to correct the optical path length and adjust the interference state according to the axial length of the examined eye E. The optical path length changing unit 41 is configured, for example, to include a corner prism and a mechanism for moving the corner prism.

[0079] The optical scanner 42 is positioned at or near the optical conjugate position of the pupil of the eye being examined (pupil conjugate position). The optical scanner 42 modifies the direction of travel of the light (measurement light) passing through the optical path used in OCT measurement. The optical scanner 42 is controlled by the computation control unit 200 described later and can deflect the measurement light in one or two dimensions.

[0080] The optical scanner 42 includes, for example, a first galvanometer mirror, a second galvanometer mirror, and a mechanism for independently driving these galvanometer mirrors. The first galvanometer mirror deflects the measurement light LS, thereby scanning the imaging region (fundus Ef or anterior eye) in a horizontal direction (x-direction) orthogonal to the optical axis of the interferometric optical system. The second galvanometer mirror deflects the measurement light LS, which has been deflected by the first galvanometer mirror, thereby scanning the imaging region in a vertical direction (y-direction) orthogonal to the optical axis of the interferometric optical system. Thus, the imaging region can be scanned in any direction in the xy-plane using the measurement light LS.

[0081] For example, by simultaneously controlling the orientation of the first galvanometer mirror and the second galvanometer mirror included in the optical scanner 42, the illumination position of the measurement light can be moved along any trajectory on the xy plane. Thus, the imaging area can be scanned according to a desired scanning pattern.

[0082] The OCT focusing lens 45 can move along the optical path (optical axis of the interference optical system) of the measurement light LS. The OCT focusing lens 45 is controlled by the operation control unit 200 described later to move along the optical path of the measurement light LS.

[0083] In some embodiments, a liquid crystal lens or an Alvarez lens is used instead of the OCT focusing lens 45. The liquid crystal lens or Alvarez lens is controlled by the arithmetic control unit 200 in the same way as the OCT focusing lens 45.

[0084] VCC lens 47 is disposed in the optical path of the measuring light, changing at least one of the cylindrical power (astigmatism power) and the cylindrical axis angle (astigmatism axis angle). VCC lens 47 has two cylindrical lenses (optical elements) arranged 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 rotate independently, so that the two axes change relative to each other. Furthermore, the two cylindrical lenses are configured to rotate integrally while maintaining the angle formed by the two axes.

[0085] The VCC lens 47 is positioned at or near the optical conjugate position of the pupil of the eye being examined. In the first embodiment, the optical scanner 42 is positioned at the optical conjugate position of the pupil of the eye being examined, therefore the VCC lens 47 is positioned near the optical conjugate position of the pupil of the eye being examined.

[0086] When the purpose is to correct the astigmatism of the examined eye E, it can be assumed that even if the VCC lens 47 is positioned near the pupil conjugate position, the deviation of the VCC lens 47's position from the pupil conjugate position has little effect on the cylindrical power and cylindrical axis angle changed by the VCC lens 47.

[0087] When the VCC lens 47 is controlled based on ophthalmic data (external or subjective measurements) of the examined eye E, this data primarily refers to measurements taken at the fovea of ​​the examined eye E. However, it can be assumed that the deviation of the VCC lens 47's placement relative to the pupil's conjugate position has a small impact on the cylindrical power and cylindrical axis angle altered by the VCC lens 47. Therefore, even when the imaging site is different from the fovea, the VCC lens 47 can be positioned near the pupil's conjugate position.

[0088] For example Figure 2 As shown, such a VCC lens 47 includes cylindrical lenses 471 and 472 (focal lengths f0 and -f0) with equal refractive power but different designations. Cylindrical lens 471 (VCC1) has a convex surface (positive power) and is configured to rotate in the rotation direction dr1 about the optical path of the measuring light LS (optical axis SO of the interference optical system). Cylindrical lens 472 (VCC2) has a concave surface (negative power) and is configured to rotate in the rotation direction dr2 about the optical axis SO. Cylindrical lenses 471 and 472 are driven by a pulse motor or similar device and rotate independently about the optical axis SO. If cylindrical lenses 471 and 472 rotate in opposite directions, the cylindrical power changes; if cylindrical lenses 471 and 472 rotate together in the same direction, the cylindrical axis angle changes.

[0089] For example, by rotating cylindrical lenses 471 and 472 in opposite directions from a state where the cylindrical axis angles of the cylindrical lenses 471 and 472 are tilted relative to the optical axis SO by a predetermined angle (e.g., 45 degrees), any cylindrical angle can be produced. Alternatively, by rotating cylindrical lenses 471 and 472 together in the same direction, any cylindrical axis angle can be produced.

[0090] [OCT Unit 100] Reference Figure 3 Here is an example illustrating the structure of the OCT unit 100. The OCT unit 100 is equipped with an optical system for acquiring OCT images of fundus ef (Ef). This optical system has the same structure as conventional sweep-source type OCT devices. That is, the optical system is an interference optical system that splits light from a wavelength-scanning (wavelength-scanning) light source into a measurement light and a reference light, causing the measurement light passing through the fundus ef (Ef) to interfere with the reference light passing through the reference light path to generate interference light, and detecting this interference light. The detection result (detection signal) of the interference light in the interference optical system is a signal representing the spectrum of the interference light and is sent to the arithmetic control unit 200.

[0091] Like a typical swept-frequency source type OCT device, the light source unit 101 is configured as a wavelength-scanning (wavelength-sweeping) light source capable of scanning (sweeping) the wavelength of the emitted light. The light source unit 101 causes the output wavelength to change over time in the near-infrared band, which is invisible to the naked eye.

[0092] The light L0 output from the light source unit 101 is guided by the optical fiber 102 to the polarization controller 103, where its polarization state is adjusted. The polarization controller 103 adjusts the polarization state of the light L0 guided within the optical fiber 102 by applying stress from the outside to the loop-shaped optical fiber 102.

[0093] The light L0, whose polarization state has been adjusted by the polarization controller 103, is guided by the optical fiber 104 to the optical fiber coupler 105 and split into the measurement light LS and the reference light LR.

[0094] The reference light LR is guided by fiber optic cable 110 to collimator 111, becoming a parallel beam. The parallel beam LR then passes through optical path length correction component 112 and dispersion compensation component 113, and is guided to corner prism 114. Optical path length correction component 112 functions as a delay unit to ensure the optical path lengths (optical distances) of the reference light LR and the measurement light LS are consistent. Dispersion compensation component 113 functions as a dispersion compensation unit to ensure the dispersion characteristics of the reference light LR and the measurement light LS are consistent.

[0095] The corner prism 114 reverses the travel direction of the reference light LR, which is formed into a parallel beam by the collimator 111. The optical path of the reference light LR incident on the corner prism 114 is parallel to the optical path of the reference light LR exiting the corner prism 114. Furthermore, the corner prism 114 can move along the incident and exit optical paths of the reference light LR. This movement changes the length of the optical path (reference optical path) of the reference light LR.

[0096] The reference light LR, after passing through the corner prism 114, is transformed from a parallel beam into a focused beam by the collimator 116 after passing through the dispersion compensation component 113 and the optical path length correction component 112, and then incident on the optical fiber 117. The reference light LR incident on the optical fiber 117 is guided to the polarization controller 118, and the polarization state of the reference light LR is adjusted.

[0097] Polarization controller 118 has, for example, the same structure as polarization controller 103. The reference light LR, whose polarization state has been adjusted by polarization controller 118, is guided by optical fiber 119 to attenuator 120, where the light intensity is adjusted under the control of operational control unit 200. The reference light LR, whose light intensity has been adjusted by attenuator 120, is guided by optical fiber 121 to fiber coupler 122.

[0098] The measurement beam LS generated by fiber coupler 105 is guided by fiber optic cable 127 and formed into a parallel beam by collimating lens unit 40. The parallel beam LS passes through optical path length changing unit 41, optical scanner 42, collimating lens 43, reflecting mirror 44, OCT focusing lens 45, field lens 46, and VCC lens 47, reaching dichroic mirror 48. Then, the measurement beam LS is reflected by dichroic mirror 48, refracted by objective lens 22, and illuminates the fundus Ef. The measurement beam LS is scattered (including reflected) at various depths within the fundus Ef. The backscattered light from the measurement beam LS based on the fundus Ef travels in the opposite direction along the same path as its initial trajectory, is guided to fiber coupler 105, and reaches fiber coupler 122 via fiber optic cable 128.

[0099] Fiber optic coupler 122 combines (interferes) the measurement light LS incident via fiber 128 and the reference light LR incident via fiber 121 to generate interference light. Fiber optic coupler 122 branches the interference light of the measurement light LS and the reference light LR at a predetermined branching ratio (e.g., 50:50), thereby generating a pair of interference lights LC. The pair of interference lights LC emitted from fiber optic coupler 122 are guided to detector 125 by fibers 123 and 124, respectively.

[0100] Detector 125 is, for example, a balanced photodiode having a pair of photodetectors that respectively detect a pair of interferometric LC beams and output the difference between the detection results of the pair of photodetectors. Detector 125 sends the detection result (detection signal) to computation control unit 200. Computation control unit 200 performs Fourier transform, etc., on each wavelength scan (each A-line) of a series of wavelength scans, thereby forming a tomographic image as an OCT image. Computation control unit 200 displays the formed image on display device 3.

[0101] The first embodiment employs a Michelson interferometer, but any type of interferometer, such as a Mach-Zehnder interferometer, can also be used appropriately. In this embodiment, the interferometric optical system, in addition to Figure 3 In addition to the structure shown, it may also include Figure 1The collimating lens unit 40, optical path length changing unit 41, optical scanner 42, collimating lens 43, reflecting mirror 44, OCT focusing lens 45, field lens 46, and VCC lens 47 shown are examples of an interference optical system according to the embodiment. The VCC lens 47 (and the VCC drive unit 47A described later) is an example of an aberration correction device (aberration correction component, astigmatic aberration correction optical component) according to the embodiment. The OCT focusing lens 45 (and the OCT focusing drive unit 45A described later) is an example of a focus position changing component according to the embodiment. At least one of the optical path length changing unit 41 and the corner prism 114 (and the reference drive unit 114A described later) is an example of an optical path length changing component according to the embodiment. At least one of the polarization controllers 103 and 118 is an example of a polarization state changing component according to the embodiment.

[0102] [Arithmetic control unit 200] Explain the structure of the arithmetic control unit 200.

[0103] exist Figure 4 and Figure 5 A block diagram illustrating a structural example of the processing system (control system) of the ophthalmic device 1 according to the first embodiment is shown. Figure 5 yes Figure 4 The functional block diagram of the structure of the analysis unit 232 is shown below. Figure 4 In, with Figures 1-3 The same reference numerals are used for the same parts, and descriptions are omitted where appropriate.

[0104] The arithmetic control unit 200 analyzes the detection signal input from the detector 125 to form an OCT image of the fundus Ef (or anterior eye). The arithmetic processing for this purpose is the same as that of conventional OCT devices with swept frequency sources.

[0105] like Figure 4 As shown, the computation control unit 200 includes a control unit 210 that controls various parts of the fundus camera unit 2, the display device 3, and the OCT unit 100. For example, the computation control unit 200 forms an OCT image of the fundus Ef and displays the formed OCT image on the display device 3.

[0106] The control of the fundus camera unit 2 includes the operation control of the observation light source 11, the shooting light source 15 and LEDs 51 and 61, the operation control of CCD image sensors 35 and 38, the operation control of LCD 39, the movement control of focusing lens 31, the movement control of OCT focusing lens 45, the movement control of reflector 67, the operation control of alignment optical system 50, the movement control of focusing optical system 60, the movement control of optical path length changing unit 41, the drive control of VCC lens 47, and the operation control of light scanner 42.

[0107] The control of the OCT unit 100 includes the operation control of the light source unit 101, the movement control of the corner prism 114, the operation control of the detector 125, the operation control of the attenuator 120, and the operation control of the polarization controllers 103 and 118.

[0108] The arithmetic control unit 200, like a conventional computer, includes a processor, RAM (Random Access Memory), ROM (Read Only Memory), hard disk drive, communication interface, etc. The computer program for controlling the ophthalmic device 1 is stored in the storage device such as the hard disk drive. The arithmetic control unit 200 may include various circuit boards, such as a circuit board for forming OCT images. Furthermore, the arithmetic control unit 200 may also include operating devices (input devices) such as a keyboard and mouse, and display devices such as an LCD.

[0109] Processors include, for example, CPUs (Central Processing Units). GPU (Graphics Processing Unit) ASIC (Application Specific Integrated Circuit) Programmable logic devices (e.g., SPLD (Simple Programmable Logic Device)) CPLD (Complex Programmable Logic Device) Circuits such as FPGA (Field Programmable Gate Array) are used. The processor implements the functions of the implementation, for example, by reading and executing programs stored in a storage circuit or storage device. The storage circuit or storage device may be included in the processor. Alternatively, the storage circuit or storage device may be located externally to the processor. In some embodiments, the functions of the arithmetic control unit 200 are implemented by more than one processor.

[0110] The fundus camera unit 2, display device 3, OCT unit 100 and computing control unit 200 can be configured as a single unit (i.e., within a single housing) or as two or more housings.

[0111] The control unit 210 includes a main control unit 211 and a storage unit 212.

[0112] (Main Control Unit 211) The main control unit 211 performs various controls by outputting control signals to each part of the ophthalmic device 1. In particular, the main control unit 211 controls the CCD image sensors 35 and 38, LCD 39, focusing drive unit 31A, optical path length changing unit 41, optical scanner 42, OCT focusing drive unit 45A, and VCC drive unit 47A for the fundus camera unit 2. Moreover, the main control unit 211 controls the light source unit 101, reference drive unit 114A, polarization controllers 103 and 118, attenuator 120, and detector 125 for the OCT unit 100.

[0113] The main control unit 211 controls the exposure time (charge accumulation time), sensitivity, frame rate, etc. of the CCD image sensor 35 or CCD image sensor 38. In some embodiments, the main control unit 211 controls the CCD image sensor 35 or CCD image sensor 38 to acquire an image of desired quality.

[0114] The main control unit 211 controls the display of fixed targets and visual acuity testing targets on the LCD 39. This allows for switching the targets presented to the tested eye E or changing the type of target. Furthermore, by changing the display position of the targets on the LCD 39, the display position of the targets for the tested eye E can be changed.

[0115] The focusing drive unit 31A moves the focusing lens 31 along the optical axis. The main control unit 211 controls the focusing drive unit 31A so that the focusing lens 31 is positioned at the desired focusing position. This changes the focusing position of the imaging optical system 30.

[0116] For example, the main control unit 211 analyzes the position of the split-image target in the light-receiving image (split-image target) obtained by the CCD image sensor 35 and controls the focus drive unit 31A and the focusing optical system 60. Alternatively, for example, the main control unit 211 controls the focus drive unit 31A and the focusing optical system 60 in response to user operations on the operation unit 240B (described later) while displaying a real-time image of the examined eye E on the display unit 240A (described later).

[0117] The main control unit 211 changes the optical path length of the measuring light LS by controlling the optical path length changing unit 41. As a result, the difference between the optical path length of the measuring light LS and the optical path length of the reference light LR is changed.

[0118] For example, the main control unit 211 analyzes the detection results of the interference light LC obtained by OCT measurement (or the OCT image formed based on the detection results) and controls the optical path length changing unit 41 to make the measurement part the desired depth position.

[0119] The main control unit 211 controls the optical scanner 42. The main control unit 211 controls the optical scanner 42 so that the measurement light LS is deflected according to the deflection pattern corresponding to the preset scanning mode.

[0120] Examples of such scanning modes include line scanning, cross scanning, ring scanning, radial scanning, concentric circle scanning, multi-line intersecting scanning, spiral scanning, Lissajous scanning, and three-dimensional scanning (including scanning that combines low-speed and high-speed scanning).

[0121] Line scanning is a scanning mode in which the measurement light LS is deflected in such a way that the trajectory of the irradiation position of the imaging (measuring) part is linear. The direction of the trajectory can be changed (rotated) in the xy plane around the optical axis.

[0122] 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 its trajectory is horizontal (x-direction). Horizontal scanning also includes scanning the measurement light LS along multiple horizontally extending scan lines arranged vertically (y-direction). In this mode, the spacing between the scan lines can be arbitrarily set. Furthermore, by making the spacing between adjacent scan lines sufficiently narrow, a three-dimensional image (three-dimensional scanning) can be formed. The same applies to vertical scanning.

[0123] A cross-scan is a scanning mode in which the measurement light LS is deflected so that its trajectory at the imaging (measuring) location forms a cross shape. For example, a cross-scan can be performed by scanning two lines whose directions intersect. The angle at which the two lines intersect can be varied. In some embodiments, the scan lengths in the B-scan direction of the two lines are the same. In some embodiments, the scan lengths in the B-scan direction of the two lines are different.

[0124] Circular scanning is a scanning mode in which the trajectory of the measurement light LS at the imaging site (measuring site) is rotated in a circular manner, for example, with the optical axis SO as the center. For example, in circular scanning, the measurement light LS is rotated in such a way that the trajectory is a perfect circle, an ellipse, or a part of a circle.

[0125] Radial scanning is a scanning mode in which the trajectory of the measurement light LS at the imaging site (measuring site) is deflected in a radial pattern, for example, around the optical axis SO. In radial scanning, the illumination position of the measurement light LS moves along a radial trajectory consisting of multiple straight lines arranged at predetermined angles. The crosshair scan described above is one type of radial scanning.

[0126] For example, in radial scanning, two or more line scans with different B-scan directions are performed. In some embodiments, the scan lengths of the B-scan directions in the two or more line scans are the same. In some embodiments, the scan length of the B-scan direction in at least one of the two or more line scans is different from the other scan lengths.

[0127] Concentric circle scanning is a scanning mode in which the trajectory of the measurement light LS at the imaging site (measuring site) is arranged in concentric circles, for example, around the optical axis SO, thus deflecting the measurement light LS. For example, in concentric circle scanning, the measurement light LS is deflected so that the trajectories of each circle are perfect circles, ellipses, or arcs (part of a circle). In some embodiments of concentric circle scanning, multiple annular scans with different diameters are performed in combination. Annular scanning is one method of concentric circle scanning.

[0128] Multi-line cross scanning is a scanning pattern in which parallel horizontal scan line groups (e.g., 5 lines) and parallel vertical scan line groups (e.g., 5 lines) are arranged orthogonally near the center of the two scan line groups.

[0129] For example, in each scan line group of a 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.

[0130] Spiral scanning is a scanning mode in which the trajectory of the measurement light LS at the imaging site (measuring site) is rotated in a spiral shape, for example, around the optical axis SO. In spiral scanning, the radius of rotation is gradually decreased (or increased) while the position of the measurement light LS is moved along a spiral trajectory.

[0131] Lissajous scanning is a scanning mode in which the irradiation trajectory of the measurement light LS at the imaging site (measurement site) is deflected such that the irradiation position of the measurement light LS is moved along a Lissajous curve. Lissajous scanning is disclosed, for example, in Japanese Patent Application Publication No. 2018-68578.

[0132] An example of a scan combining low-speed and high-speed scanning is an ammonite scan (3D scan). An ammonite scan is a scanning mode in which the scanning reference position (scan center position), which is a high-speed circular scan, moves along the scanning pattern of a low-speed spiral scan. That is, while moving the scan center position along the spiral scanning pattern, circular scans are performed sequentially around each scan center position. As described above, the low-speed scan can be defined by any one-dimensional or two-dimensional scanning mode, and the high-speed scan can be defined by any one-dimensional or two-dimensional scanning mode. Examples of low-speed or high-speed scans include line scan, cross scan, circular scan, radial scan, concentric circle scan, multi-line intersecting scan, spiral scan, and Lissajous scan.

[0133] By scanning the imaging area with a measurement light LS according to a deflection pattern corresponding to the above scanning mode, a tomographic image as an OCT image can be obtained on the plane formed by the direction along the scan line (scan trajectory) and the fundus depth direction (z direction).

[0134] The OCT focusing drive unit 45A moves the OCT focusing lens 45 along the optical axis of the measurement light LS. The main control unit 211 controls the OCT focusing drive unit 45A so that the OCT focusing lens 45 is positioned at the 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.

[0135] 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 the statistical value of the evaluation value) corresponding to the image quality of the OCT image formed based on the detection result.

[0136] When a liquid crystal lens or an Alvarez lens is used 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 way as it controls the OCT focusing drive unit 45A.

[0137] The VCC drive unit 47A causes the cylindrical lenses 471 and 472 to rotate independently about the optical axis of the measuring light LS. This changes at least one of the cylindrical power and the cylindrical axis angle.

[0138] For example, the main control unit 211 controls the VCC drive unit 47A based on the signal-to-noise ratio of the detection result of the interferometric light LC obtained by OCT measurement or an evaluation value (including statistical values ​​of the evaluation value) corresponding to the image quality of the OCT image formed based on the detection result. In some embodiments, the main control unit 211 controls the VCC drive unit 47A based on the signal-to-noise ratio of the detection result of the interferometric light LC obtained by deflecting the measured light LS according to a deflection pattern corresponding to the annular scan or an evaluation value (including statistical values ​​of the evaluation value) corresponding to the image quality of the OCT image formed based on the detection result.

[0139] When a liquid crystal lens, deformable mirror, or Alvarez lens is used instead of VCC lens 47, the main control unit 211 can control the liquid crystal lens, deformable mirror, or Alvarez lens in the same way as the VCC drive unit 47A.

[0140] 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 center frequency of the emitted light, changing the sweep speed of the emitted light, changing the sweep frequency, and changing the sweep wavelength range.

[0141] The reference drive unit 114A moves the corner prism 114, which is positioned in the optical path of the reference light, along the optical path. As a result, the difference between the optical path length of the measuring light LS and the optical path length of the reference light LR is changed.

[0142] For example, the main control unit 211 analyzes the detection results of the interferometric light LC obtained by OCT measurement (or the OCT image formed based on the detection results) to control the reference drive unit 114A in a way that makes the measurement location the desired depth position. In some embodiments, either the optical path length changing unit 41 or the reference drive unit 114A is provided.

[0143] The main control unit 211 controls the polarization controllers 103 and 118. For example, the main control unit 211 controls the polarization controllers 103 and 118 based on the signal-to-noise ratio of the detection result of the interferometric light LC obtained by OCT measurement or an evaluation value (including statistical values ​​of the evaluation value) corresponding to the image quality of the OCT image formed based on the detection result.

[0144] The main control unit 211 controls the attenuator 120. For example, the main control unit 211 controls the attenuator 120 based on the signal-to-noise ratio of the detection result of the interferometric light LC obtained by OCT measurement or an evaluation value (including statistical values ​​of the evaluation value) corresponding to the image quality of the OCT image formed based on the detection result.

[0145] The main control unit 211 controls the detector 125. The control of the detector 125 includes the control of exposure time (charge accumulation time), sensitivity, frame rate, etc.

[0146] The moving mechanism 150 causes the fundus camera unit 2 (OCT unit 100) to move three-dimensionally relative to the examined eye E. For example, the main control unit 211 can control the moving mechanism 150 to move the optical system installed in the fundus camera unit 2 in three dimensions. This control is used for alignment and tracking. Tracking refers to moving the device's optical system in a way that matches the movement of the examined eye E. When tracking is performed, alignment and focus are performed in advance. Tracking is a function that maintains the proper positional relationship after alignment and focus are achieved by moving the device's optical system in real time, based on images obtained from video capture of the examined eye E, and matching the position and orientation of the examined eye E.

[0147] In some embodiments, the main control unit 211 corrects the position of the scanning range used for OCT imaging in real time based on tracking information obtained through tracking control (tracking information obtained by making the optical system (interference optical system) follow the movement of the examined eye E). The main control unit 211 can control the optical scanner 42 so that the calibrated scanning range is scanned with the measurement light LS.

[0148] In some embodiments, the main control unit 211 controls the optical system constituting the ophthalmic device 1 based on setting information pre-stored in the storage unit 212, thereby changing the optical conditions (imaging conditions, measurement conditions) of the optical system. In this case, the main control unit 211 can pre-generate setting information based on the detection results of interference light LC obtained in a prediction measurement (pre-imaging) performed before the actual measurement (actual imaging) or from an OCT image formed based on the detection results. Alternatively, the main control unit 211 can also pre-generate setting information based on eye shape information (or eye aberration information) statistically obtained from multiple different eye information sources.

[0149] The main control unit 211 acts as a display control unit, causing the display device 3 (or the display unit 240A described later) to display various information. The information displayed on the display device 3 includes imaging results (observation images, OCT images (images of the examined eye formed based on the detection results of interference light LC obtained by scanning with measurement light LS), measurement results (measured values), image quality evaluation values ​​(described later), statistical values ​​calculated based on the evaluation values, and evaluation index information corresponding to the evaluation values, etc. The main control unit 211 can display the image quality evaluation values, statistical values, or evaluation index information of the OCT image in association with the OCT image on the display device 3.

[0150] In addition, the main control unit 211 performs the processing of writing data to the storage unit 212 and the processing of reading data from the storage unit 212.

[0151] (Storage Department 212) Storage unit 212 stores various types of data. Examples of data stored in storage unit 212 include image data containing OCT images, fundus image data, and information about the eye being examined. Information about the eye being examined includes patient ID, name, and other patient-related information, as well as left / right eye identification information and other eye-related information. Additionally, storage unit 212 stores eye examination data pre-acquired by external devices (e.g., ophthalmometer, auto-ophthalmometer), various programs used to operate ophthalmic device 1, and other data. Eye examination data includes the astigmatism power and astigmatic axis angle of the eye being examined. Eye examination data may also include the spherical power of the eye being examined. Eye examination data may include at least one of the spherical power, astigmatism power, and astigmatic axis angle of the eye being examined.

[0152] Furthermore, the storage unit 212 is capable of storing the aforementioned setting information. The setting information is used to set the optical conditions of the optical system constituting the ophthalmic device 1. More specifically, the setting information is used to set the optical conditions of the optical system so that the image quality of the image formed based on OCT data reaches a predetermined quality level or higher; the OCT data is data acquired using the optical system constituting the ophthalmic device 1. In an example of the optical conditions of the optical system constituting the ophthalmic device 1, the setting includes the focusing position of the measurement light LS used for 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 relative to the examined eye E.

[0153] At least a portion of the data stored in storage unit 212 can be stored in a storage unit located outside of ophthalmic device 1. For example, ophthalmic device 1 can be communicatively connected to a server device capable of storing at least a portion of the aforementioned data via a network such as an intra-hospital LAN (Local Area Network). Alternatively, ophthalmic device 1 and the server device can be connected via a WAN (Wide Area Network) such as the Internet. Furthermore, ophthalmic device 1 and the server device can be connected via a network combining LAN and WAN.

[0154] (Image forming unit 220) The image forming unit 220 forms image data of the fundus Ef or the anterior eye OCT image based on the detection signal (interference signal, OCT data) from the detector 125. That is, the image forming unit 220 forms an image of the examined eye E based on the detection result of the interference light LC by the interference optical system. Similar to conventional sweep source type optical coherence tomography, this processing includes noise removal (noise reduction), filtering, FFT (Fast Fourier Transform), and other processing. The image data thus acquired is a dataset of image data formed by imagerizing the reflection intensity distribution in multiple A-lines (paths of each measurement light LS within the examined eye E).

[0155] When performing an OCT scan on each scan region, the image forming unit 220 is able to form an image (OCT image) of the examined eye E on each scan region. In this embodiment, the image forming unit 220 is able to form an OCT image of the examined eye E on each scan region based on OCT data acquired on each scan region under different optical conditions.

[0156] To improve image quality, multiple datasets collected by repeating scans with the same pattern multiple times can be superimposed (averaged).

[0157] The image forming unit 220 is configured, for example, to include the aforementioned circuit board. Furthermore, in this specification, "image data" and "image" based on "image data" are sometimes considered to be the same. Additionally, the location of the fundus ef region and its image are sometimes considered to be the same.

[0158] (Data Processing Department 230) The data processing unit 230 performs various data processing (image processing) and analysis on the detection results of the interferometric light LC or the image formed by the image forming unit 220. For example, the data processing unit 230 performs various correction processes such as signal-to-noise ratio analysis of the interferometric signal, brightness correction of the image, and dispersion correction.

[0159] In addition, the data processing unit 230 performs various image processing and analysis on the images (fundus images, anterior eye images, etc.) obtained by the fundus camera unit 2.

[0160] The data processing unit 230 performs known image processing such as interpolation processing to interpolate pixels between two-dimensional tomographic images, forming image data of a three-dimensional image of the fundus Ef or the examined eye E. Furthermore, image data for a three-dimensional image refers to image data where pixel positions are defined by a three-dimensional coordinate system. Image data for a three-dimensional image can be composed of voxels arranged in three dimensions. This image data is called volume data or voxel data. When displaying an image based on volume data, the data processing unit 230 performs rendering processing on the volume data (volume rendering, MIP (Maximum Intensity Projection), etc.) to form image data of a simulated three-dimensional image viewed from a specific viewing direction. This simulated three-dimensional image is displayed on a display device such as the display unit 240A.

[0161] Furthermore, image data as a three-dimensional image can be stacked into multiple tomographic images. Stacked data is image data obtained by arranging multiple tomographic images obtained along multiple scan lines in three dimensions based on the positional relationship of the scan lines. That is, stacked data is image data obtained by representing multiple tomographic images that were originally defined by their respective two-dimensional coordinate systems in a three-dimensional coordinate system (i.e., embedding them in a three-dimensional space).

[0162] The data processing unit 230 is capable of constructing OCTA images (vascular emphasis images, angiography images) that highlight retinal vessels and choroidal vessels based on data collected in a time-series manner via OCT scanning (e.g., B-scan data, OCT data). The OCTA images can be images showing cross-sectional structures or frontal images.

[0163] In some embodiments, the data processing unit 230 compares two OCT images obtained by repeatedly performing B-scans on approximately the same area of ​​the examined eye E, transforms the pixel values ​​of the portion with varying signal intensity into pixel values ​​corresponding to the amount of change, thereby constructing an emphasized image (motion contrast image) highlighting the portion with varying intensity. Furthermore, the data processing unit 230 can extract information corresponding to a predetermined thickness in the desired area from the constructed multiple emphasized images and construct an en-face image, thereby forming an OCTA (Optical Characteristic Angiography) image.

[0164] The data processing unit 230 is capable of aligning fundus images and OCT images. When acquiring fundus images and OCT images in parallel, since the two optical systems are coaxial, the fundus images and OCT images acquired (approximately) simultaneously can be aligned using the optical axis of the imaging optical system 30 as a reference. Furthermore, regardless of the timing of the acquisition of the fundus images and OCT images, alignment can be performed between the OCT image projected onto the xy plane and the fundus image, thereby aligning the OCT image with the fundus image. This alignment method can also be applied when the optical system for fundus image acquisition and the optical system for OCT measurement are not coaxial. Moreover, even when the two optical systems are not coaxial, if the relative positional relationship between the two optical systems is known, the same alignment as when they are coaxial can be performed by referring to that relative positional relationship.

[0165] Such a data processing unit 230 includes an image synthesis unit 231 and an analysis unit 232.

[0166] (Image Composition Unit 231) The image compositing unit 231 combines multiple images formed by the image forming unit 220 to generate a composite image. Specifically, the image compositing unit 231 aligns multiple OCT images formed by the image forming unit 220 according to each scan area to generate the composite image.

[0167] In some embodiments, the image synthesis unit 231 generates a composite image by aligning multiple OCT images formed in each scan area based on the different optical conditions of each scan area or the setting information of the optical system corresponding to the optical conditions.

[0168] In some embodiments, the image synthesis unit 231 aligns the multiple OCT images to generate a synthesized image in such a way that the correlation value of the repeated regions of the peripheral regions of each of the multiple OCT images formed according to each scanning region is maximized.

[0169] In some embodiments, the image synthesis unit 231 generates a synthesized image by aligning multiple OCT images based on feature regions such as layer regions, blood vessel regions, or lesion sites depicted in the peripheral region of each of the multiple OCT images formed according to each scanning region.

[0170] (Analysis Department 232) In addition to the analysis processing described above, the analysis unit 232 also performs analysis processing to estimate the substantial cross-sectional structure of the examined eye E based on OCT data obtained through previously performed OCT scans (high-speed scans) or OCT images formed based on such OCT data. For example, the analysis unit 232 performs analysis processing to estimate the substantial cross-sectional structure of the examined eye E for each scan region based on OCT data or OCT images obtained through previously performed OCT scans for each scan region.

[0171] Such an analysis unit 232 includes an image position determination unit 232A and an image quality evaluation value calculation unit 232B.

[0172] (Image position determination unit 232A) The image location determination unit 232A determines the substantial cross-sectional structure of the eye E being examined based on the depth direction position of the region of interest (in a broad sense, the object being measured (the eye being examined)) in the image. Examples of regions of interest include fundus Ef (retina, retinal pigment epithelium), which has a curved cross-sectional shape.

[0173] In some embodiments, the image position determination unit 232A determines the centroid position of the depth direction (depth range) in the B-scan image (tomographic image), which is an OCT image, and determines the depth direction position of the region of interest in the B-scan image based on the determined centroid position of the depth direction. For example, the image position determination unit 232A accumulates (or averages) the pixel values ​​of the B-scan image in a direction orthogonal to the A-scan direction (depth direction). Then, the image position determination unit 232A determines the centroid position of the depth direction based on the obtained cumulative distribution in the A-scan direction.

[0174] In some embodiments, the image position determination unit 232A determines a region with a predetermined shape as a region depicting the area of ​​interest based on the OCT image, and determines the position of the determined region in the depth direction in the OCT image.

[0175] (Image quality evaluation value calculation unit 232B) The image quality evaluation value calculation unit 232B determines the substantial cross-sectional structure of the examined eye E, including the region of interest, based on an evaluation value (including statistical values ​​of the evaluation value) corresponding to the image quality (e.g., signal-to-noise ratio). The evaluation value calculation process involves analyzing the detection results of the interference light LC, the OCT image formed by the image forming unit 220, or a segmented image obtained by segmenting the OCT image. The segmented image can be an image obtained by segmenting the OCT image corresponding to each of a plurality of scanning regions obtained by segmenting the scanning region. Alternatively, the segmented image can be an image obtained by segmenting the OCT image corresponding to each of a plurality of pre-defined scanning regions.

[0176] The image quality evaluation value calculation unit 232B calculates any evaluation value that quantitatively represents image quality. Typically, the evaluation value is calculated in such a way that the higher the image quality (image quality), the larger the value. The evaluation value calculation processing performed by the image quality evaluation value calculation unit 232B can be any processing. For example, the image quality evaluation value calculation unit 232B can perform processing using any known techniques such as signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), root mean square (RMS) granularity, Wiener spectrum, modulation transfer function (MTF), and quality index (QI).

[0177] In the first example of the evaluation value calculation process, the image quality evaluation value calculation unit 232B calculates the differential histogram of the image to be calculated, and uses the maximum value of the brightness value (differential value) of the pixels that have a predetermined proportion or higher in the calculated differential histogram throughout the entire image to calculate the image quality evaluation value. Specifically, the image quality evaluation value calculation unit 232B calculates the difference between the maximum and minimum values ​​of the differential values ​​that are above a predetermined threshold (e.g., 20%) as the image quality evaluation value. At this time, the image quality evaluation value is higher when the image quality reaches or exceeds a predetermined image quality level, and decreases as the image quality deviates from the predetermined image quality level.

[0178] In the second example of the evaluation value calculation process, the data processing unit 230 (or analysis unit 232) applies a predetermined analysis process (e.g., segmentation process) to the evaluation region, which is a region defined for the image corresponding to a predetermined part in the examined eye E. As a result, the image quality evaluation value calculation unit 232B determines the image region (signal region) corresponding to the desired part (tissue) and other image regions (non-signal regions). Next, the image quality evaluation value calculation unit 232B generates a luminance histogram in the signal region and a luminance histogram in the non-signal region. Subsequently, the image quality evaluation value calculation unit 232B calculates an evaluation value corresponding to the image quality based on the degree of overlap between these two histograms. For example, the evaluation value is defined in the range of 0 to 100, such that when the two histograms completely overlap, the evaluation value = 0, and when the two histograms completely separate, the evaluation value = 100. This evaluation value calculation may include, for example, normalizing the two histograms, generating a probability distribution function, and calculating the evaluation value using a predetermined formula.

[0179] Furthermore, the image quality evaluation value calculation unit 232B can calculate known parameters representing image quality, such as signal-to-noise ratio (SNR), spatial resolution, and contrast ratio, for the image of the object being calculated. In this case, the image quality evaluation value is higher when the image quality is above a predetermined image quality level, and decreases as the image quality deviates from the predetermined image quality level.

[0180] The image quality evaluation value calculation unit 232B calculates the image quality evaluation value of the entire OCT image, or calculates the image quality evaluation value for each segmented image corresponding to each of the multiple scanning regions.

[0181] Furthermore, the image quality evaluation value calculation unit 232B can calculate statistical values ​​of multiple evaluation values ​​relative to multiple segmented images. Examples of statistical values ​​include maximum value, minimum value, median, mean, mode, range, variance, standard deviation, weighted average with a larger weighting coefficient closer to the region of interest (optical axis of the optical system), or a value using a predetermined evaluation formula that uses any of the above statistical values.

[0182] As an example of an evaluation formula, there is a formula such that the higher the sum of the evaluation values ​​of multiple segmented images and the smaller the fluctuation of the evaluation values ​​of multiple segmented images, the larger the value of the evaluation formula, VCCQ. In this case, for example, the value of the evaluation formula, VCCQ, is the value obtained by dividing the sum of the evaluation values ​​of multiple segmented images by (the standard deviation of the multiple evaluation values ​​+ 1).

[0183] The main control unit 211 estimates the actual cross-sectional structure of the examined eye E based on the analysis results obtained by the analysis unit 232, and changes the optical conditions of the optical system synchronously with the low-speed scanning cycle based on the estimated cross-sectional structure. In some embodiments, the main control unit 211 estimates the actual cross-sectional structure of the examined eye E for each scanning area, and changes the optical conditions of the optical system synchronously with the low-speed scanning cycle for each scanning area based on the estimated cross-sectional structure.

[0184] The data processing unit 230, which functions as described above, includes, for example, the aforementioned processor, RAM, ROM, hard disk drive, circuit board, etc. A computer program that enables the microprocessor to perform the aforementioned functions is pre-stored in the storage device such as the hard disk drive.

[0185] (User interface 240) The user interface 240 includes a display unit 240A and an operation unit 240B. The display unit 240A comprises the display device and display apparatus 3 of the aforementioned calculation control unit 200. The operation unit 240B comprises the operation device of the aforementioned calculation control unit 200. The operation unit 240B may include various buttons and keypads provided on the housing and exterior of the ophthalmic device 1. For example, when the fundus camera unit 2 has the same housing as a conventional fundus camera, the operation unit 240B may include a joystick, operation panel, etc., provided on the housing. Furthermore, the display unit 240A may include various display devices such as a touch panel provided on the housing of the fundus camera unit 2.

[0186] Furthermore, the display unit 240A and the operation unit 240B do not need to be configured as separate devices. For example, a device integrating display and operation functions, such as a touch panel, can be used. In this case, the operation unit 240B is configured to include the touch panel and a computer program. The operation content of the operation unit 240B is input to the control unit 210 as an electrical signal input. Alternatively, a graphical user interface (GUI) displayed on the display unit 240A can be used for operation and information input with the operation unit 240B.

[0187] The examined eye E (fundus Ef, anterior eye) is an example of the "object to be measured" in this embodiment. The optical system, optical path length changing unit 41, OCT focusing lens 45, and VCC lens 47 (interference optical system) included in the OCT unit 100 are examples of the "optical system" in this embodiment. The OCT focusing lens 45, corner prism 114, optical path length changing unit 41, and polarization controller 103 are examples of "one or more optical elements" in this embodiment. Measuring the focusing position of light LS, measuring the polarization component of light LS, aberration correction component, measuring the optical path length difference between light LS and reference light LR, or the position of the optical system relative to the examined eye E are examples of the "optical conditions of the optical system" in this embodiment. The ophthalmic device 1 is an example of the "OCT device" in this embodiment. The optical path length changing unit 41, or corner prism 114 and reference drive unit 114A, are examples of the "optical path length difference changing component" in this embodiment. The OCT focusing lens 45 is an example of the "focusing lens" in this embodiment. VCC lens 47 is an example of an "aberration correction device" in the embodiment. Display device 3 or display section 240A is an example of a "display unit" in the embodiment.

[0188] The following describes the case where the ophthalmic device 1 of the first embodiment performs an ammonite scan as an OCT scan of the examined eye E. However, this embodiment can also be applied to cases where an OCT scan of the examined eye E is performed using a scanning mode other than ammonite scanning.

[0189] Figure 6 An explanatory diagram of ammonite scanning according to the first embodiment is shown.

[0190] The ammonite scanning in the first embodiment is a scanning mode in which the scanning center position of the high-speed scan is moved along the scanning pattern (scanning trajectory) of the low-speed scan, and high-speed scans are performed one or more times sequentially with a predetermined scanning pattern, using the moved scanning center position as a reference. In the ammonite scanning of this embodiment, the high-speed scan is a circular scan, the low-speed scan is a spiral scan, and the sequentially performed circular scans are performed in a manner that intersects with the scanning pattern of the previous circular scan. That is, circular scans are performed sequentially in a manner in which the scanning patterns of two adjacent circular scans intersect.

[0191] exist Figure 6The image schematically illustrates the scanning pattern Lsc for low-speed scanning and the scanning pattern HS for high-speed scanning. n (n is an integer greater than or equal to 4), HS n-1 HS n-2、 HS n-3 .

[0192] As described above, with regard to ammonite scanning, by combining low-speed and high-speed scanning, the eye E being examined can be scanned from various scanning directions with simple control. In particular, it is possible to scan at high density in a short time in the area near the center of the ammonite scan (the scanning center position of the low-speed scan), and to spend more time scanning at low density further away from the center, thereby enabling the scanning of a wide-angle area including the region of interest with simple control.

[0193] According to this embodiment, by scanning the eye E under examination with ammonite scanning, regardless of the cross-sectional structure of the eye E under examination, it is possible to measure or photograph the eye E with higher image quality and a wider angle.

[0194] exist Figure 7 The diagram schematically illustrates an OCT image formed based on OCT data obtained through ammonite scanning according to the first embodiment. Figure 7 For ease of explanation, the process of generating an OCT image will be described, but the same applies to generating an OCT image.

[0195] First, the main control unit 211 sets the scanning area for ammonite scanning for the eye being examined, E. The setting parameters for setting the scanning area for ammonite scanning include the scan start position (scan center position) for low-speed scanning, the scan end position for low-speed scanning, the scan speed for low-speed scanning, the rate of change of the scan radius from the scan start position for low-speed scanning, the scan speed for high-speed scanning, and the scan radius for high-speed scanning.

[0196] The main control unit 211 controls the optical scanner 42 and the OCT unit 100, etc., to repeatedly perform high-speed scanning by moving the scanning center position along the scanning pattern of low-speed scanning and performing two or more high-speed scans (circular scans) centered on the moved scanning center position. The main control unit 211 controls the image forming unit 220 to form an OCT image (tomographic image, B-scan image) based on the acquired OCT data each time a circular scan is performed. Next, the main control unit 211 controls the data processing unit 230 to compare two OCT images obtained by repeatedly performing circular scans (B-scans) on approximately the same area of ​​the examined eye E, and sequentially form an OCTA image. Thus, an OCTA image IMG is formed by arranging the OCTA images formed in the high-speed scanning direction in the low-speed scanning direction.

[0197] Next, the main control unit 211 controls the data processing unit 230 to perform a coordinate transformation to the Cartesian coordinate system for each of the multiple OCTA images formed in the high-speed scanning direction, generating strip images ST0, ST1, ST2, etc. For example, by... Figure 6 A strip image ST0 is obtained by circumferential scanning of the scanning pattern HS0. A strip image ST1 is obtained by circumferential scanning of the scanning pattern HS1, which intersects with HS0. A strip image ST2 is obtained by circumferential scanning of the scanning pattern HS2, which intersects with HS1. At this point, OCTA images containing artifacts caused by the movement or blinking of the examined eye E during the circumferential scanning can be discarded. Only the OCTA images without artifacts are transformed using coordinate transformation to obtain the strip images.

[0198] The main control unit 211 controls the data processing unit 230 to align the strip images ST1, ST2, ... sequentially, using the strip image ST0 as a reference image, thereby generating composite images CIMG0, CIMG1, CIMG2, ... CIMGm (where m is an integer greater than or equal to 2). The data processing unit 230 aligns images based on images within overlapping scan regions in two adjacent strip images (e.g., vascular regions in OCTA images).

[0199] Therefore, it is possible to pass Figure 6 ammonite scanning acquisition Figure 7 The composite image CIMGm.

[0200] [Work Example] An example of the operation of the ophthalmic device 1 according to the first embodiment will be explained.

[0201] Figures 8 to 13B An example of the operation of the ophthalmic device 1 according to the first embodiment is shown.

[0202] Figure 8 An example is schematically shown of multiple scanning regions obtained by segmenting the scanning area of ​​an OCT scan performed in the ophthalmic device 1 of the first embodiment. Figure 8 In, with Figure 6 The same reference numerals are used for the same parts, and descriptions are omitted where appropriate.

[0203] For example, such as Figure 8 As shown, the main control unit 211 defines a central region SAR1, an intermediate region SAR2 surrounding the central region SAR1, and a peripheral region SAR3 surrounding the intermediate region SAR2 in the eye being examined E. The intermediate region SAR2 is positioned outside the central region SAR1, surrounding it. Figure 8In this context, the intermediate region SAR2 can be two or more regions arranged in concentric circles. The peripheral region SAR3 is a region arranged outside the outermost intermediate region of one or more intermediate regions including the central region SAR1, and surrounding the outermost intermediate region.

[0204] The main control unit 211 can press Figure 8 The optical conditions of the optical system are changed in each region shown. Thus, when the object being measured is photographed at a wide angle, it is possible to acquire an OCT image of the examined eye E with good image quality without performing a pre-scan, while minimizing changes in the image caused by changes in optical conditions during scanning.

[0205] Figure 9 A timing diagram illustrating an example of the timing of optical system changes during a single-scan process performed in the ophthalmic device 1 of the first embodiment. Figure 9 In the diagram, the horizontal axis represents time, and the vertical axis schematically represents the signal level of the control signal used to control each control timing.

[0206] like Figure 9 As shown, during a single scan performed by a combination of high-speed scanning (circular scanning) controlled by period Tfc and low-speed scanning (spiral scanning) controlled by period Tsc (>Tfc), the main control unit 211 synchronously changes the optical conditions of the optical system with the control timing (period of the low-speed scan). The timing of changing the optical conditions of the optical system can be the interval between the execution timings of two consecutive A-scans.

[0207] That is, the main control unit 211 sequentially executes the scanning operations on the pre-set scanning areas of the fundus Ef. Figure 6 The OCT scan shown. The main control unit 211 controls the image forming unit 220 to form an OCT image each time OCT data is acquired through an OCT scan. Furthermore, the main control unit 211 controls the analysis unit 232 to analyze the OCT image formed by the image forming unit 220, calculating the position of the region of interest in the OCT image and the image quality evaluation value of the OCT image. Next, as... Figure 9 As shown, the main control unit 211 synchronously changes the optical conditions of the optical system based on the position of the region of interest in the OCT image and the image quality evaluation value of the OCT image at the start time of the low-speed scan of the next OCT scan.

[0208] Figure 10 The diagram schematically illustrates the focusing position of the measuring light LS, which varies depending on each scan region in the B-scan image acquired by the ophthalmic device 1 of the first embodiment. Figure 10 In the diagram, the focus position of the measurement beam LS in the segmented image obtained by dividing the B-scan image IMG10 correspondingly with the scan area is shown as beam waists Bw1 to Bw6.

[0209] Figure 10 The B-scan image IMG10 shown is a tomographic image taken when the OCT focusing lens 45 is moved by each scan region so that the focusing position of the measurement light LS is configured in or near the retinal pigment epithelium in the fundus Ef.

[0210] For example, the main control unit 211 pre-installed Figure 10 An OCT scan (e.g., a circular scan) is performed at a different scanning location than the fundus Ef in the B-scan image IMG10 shown. Then, the main control unit 211 moves the OCT focusing lens 45 synchronously with the start of the low-speed scan for each scanning area based on the OCT data or the B-scan image formed based on the OCT data. As a result, even when performing an OCT scan on the fundus Ef at a wide angle, a tomographic image of the fundus Ef can be acquired with good image quality.

[0211] Figure 11 A tomographic image is schematically shown when the difference in optical path length between the measuring light LS and the reference light LR is varied according to each scanning region using the ophthalmic device 1 of the first embodiment. Figure 11 The image shows segmented images IMG21 to IMG26 obtained by segmenting the B-scan image corresponding to the scan area.

[0212] For example, the main control unit 211 performs an OCT scan (e.g., a circular scan) in advance. Then, based on the OCT data or a B-scan image formed based on the OCT data, the main control unit 211 controls at least one of the corner prism 114 and the reference drive unit 114A, as well as the optical path length changing unit 41, synchronously with the start of the low-speed scan for each scan area. At this time, the main control unit 211 controls the image synthesis unit 231 to align the segmented images IMG21 to IMG26 in the depth direction to generate a synthesized image of the smoothly connected region of interest (retinal pigment epithelium) of the fundus Ef. Thus, even when performing an OCT scan of the fundus Ef at a wide angle, a tomographic image of the fundus Ef can be obtained with good image quality.

[0213] Figure 12A and Figure 12B A flowchart illustrating an operational example of the ophthalmic device 1 according to the first embodiment is shown. The storage unit 212 stores information for performing... Figure 12A and Figure 12B The computer program for processing is shown. The main control unit 211 operates according to this computer program, thereby executing... Figure 12A and Figure 12B The processing shown.

[0214] Figure 13A and Figure 13B Show Figure 12AThe flowchart of step S6 is shown. Storage unit 212 stores data for implementing... Figure 13A and Figure 13B The computer program for processing is shown. The main control unit 211 operates according to this computer program, thereby executing... Figure 13A and Figure 13B The processing shown.

[0215] (S1: Set the optical system to the reference position) like Figure 12A As shown, firstly, the main control unit 211 sets the optical conditions of the optical system constituting the ophthalmic device 1 to predetermined initial conditions, and sets the optical system to a reference position based on the set initial conditions.

[0216] (S2: Align) Next, with the fixation target presented at the predetermined fixation position, the main control unit 211 performs alignment adjustment of the optical system relative to the examined eye E. Examples of alignment adjustment include both manual and automatic adjustments.

[0217] When manual alignment is performed, the main control unit 211 projects a pair of alignment indicators onto the eye being examined, E, using the alignment optics system 50. In the display unit 240A, an alignment highlight is displayed as the light-receiving image of these alignment indicators. Additionally, the main control unit 211 displays an alignment scale on the display unit 240A indicating the position of the moving target, which is the pair of alignment highlights. The alignment scale may be, for example, a bracket-shaped image.

[0218] When the positional relationship between the examined eye E and the fundus camera unit 2 (objective lens 22) is appropriate—that is, when the distance (working distance) between the examined eye E and the fundus camera unit 2 is appropriate and the optical axis of the optical system of the fundus camera unit 2 is (approximately) aligned with the axial length (corneal apex position) of the examined eye E—a pair of alignment highlights are temporarily imaged and projected onto the examined eye E at predetermined positions (e.g., the midpoint between the corneal apex and the center of corneal curvature) using known methods. The examiner (user) moves the fundus camera unit 2 three-dimensionally to guide the pair of alignment highlights into the alignment scale, thereby enabling alignment adjustments of the optical system relative to the examined eye E.

[0219] When automatic alignment adjustment is performed, a moving mechanism 150 is used to move the fundus camera unit 2. The data processing unit 230 determines the position of each alignment highlight in the image displayed on the display unit 240A and calculates the displacement of the determined alignment highlight position relative to the alignment scale. The main control unit 211 moves the fundus camera unit 2 using the moving mechanism 150 to eliminate this displacement. The position of each alignment highlight can be determined, for example, by calculating the brightness distribution of each alignment highlight and calculating the center of gravity position based on the brightness distribution. Since the position of the alignment scale is fixed, the target displacement can be calculated, for example, by calculating the displacement of the center position of the alignment scale relative to the aforementioned center of gravity position. The direction and distance of movement of the fundus camera unit 2 can be determined by referring to the unit movement distance in each of the preset x, y, and z directions (for example, by pre-measuring the result that if the fundus camera unit 2 is moved by a certain amount in a certain direction, the alignment index will move by a certain amount in that direction). The main control unit 211 generates a signal corresponding to the determined direction and distance of movement and sends the signal to the moving mechanism 150. Therefore, the position of the optical system relative to the eye being examined, E, is automatically adjusted.

[0220] (S3: Set the scanning area) The main control unit 211 sets the scanning area so that the region of interest in the examined eye E is the scanning center position (corresponding to the position of the optical axis of the optical system). For example, as Figure 6 or Figure 8 As shown, the main control unit 211 sets ammonite scanning as the scanning mode and sets multiple scanning areas to be scanned.

[0221] (S4: OCT scan) Next, the main control unit 211 controls the optical scanner 42 and the OCT unit 100, etc., to perform ammonite scanning on the scanning area set in step S3. In step S4, as... Figure 8 The ammonite scan is performed across multiple scanning regions, as shown.

[0222] (S5: Forming an OCT image) Next, the main control unit 211 controls the image forming unit 220 to sequentially form OCT images based on the OCT data obtained by performing OCT scans on multiple scanning areas sequentially executed in step S4.

[0223] In some embodiments, the main control unit 211 controls the image compositing unit 231 to align the multiple OCT images formed in step S5 to generate a composite image. The composite image is one of the OCT images.

[0224] (S6: Analysis) Next, the main control unit 211 controls the analysis unit 232 to perform analysis processing 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.

[0225] The details of step S6 will be described later.

[0226] (S7: Change the optical conditions of the optical system?) Next, the main control unit 211 determines whether to change the optical conditions of the optical system based on the processing results obtained through the analysis process performed in step S6. For example, the main control unit 211 determines whether to change the optical conditions of the optical system based on the analysis process results in step S6 and whether there are any optical conditions of the optical system that should be changed.

[0227] Specifically, when the main control unit 211 determines that the optical conditions of the optical system should be changed, it determines that the optical conditions of the optical system should be changed when it determines at least one of the following: the correction amount for the difference in optical path length between the measuring light LS and the reference light LR, the correction amount for the focus position of the measuring light LS, the correction amount for the polarization state of the light L0 from the light source unit 101 or the measuring light LS, the aberration correction amount, and the movement correction amount of the optical system. On the other hand, when none of the above-mentioned correction amounts are determined, the main control unit 211 determines that the optical conditions of the optical system should not be changed.

[0228] When it is determined in step S7 that the optical conditions of the optical system have been changed (S7: Yes), the operation of the ophthalmic device 1 proceeds to step S8. When it is determined in step S7 that the optical conditions of the optical system have not been changed (S7: No), the operation of the ophthalmic device 1 proceeds to step S10.

[0229] (S8: When should low-speed scanning begin?) When it is determined in step S7 that the optical conditions of the optical system have been changed (S7: Yes), the main control unit 211 determines whether it is the start time for a low-speed scan constituting an ammonite scan. For example, the main control unit 211 determines whether it is the start time for a low-speed scan (spiral scan) based on the control content of the optical scanner 42 for performing an OCT scan on the scan area set in step S3.

[0230] When it is determined in step S8 that it is the start time for low-speed scanning (S8: Yes), the operation of ophthalmic device 1 proceeds to step S9. When it is determined in step S8 that it is not the start time for low-speed scanning (S8: No), the operation of ophthalmic device 1 repeats step S8.

[0231] (S9: Change the optical conditions of the optical system) When it is determined in step S8 that it is the start time of low-speed scanning (S8: Yes), the main control unit 211 changes the optical conditions of the optical system.

[0232] For example, the main control unit 211 controls the OCT focusing drive unit 45A to move the position on the optical axis of the OCT focusing lens 45 by a movement amount corresponding to the correction amount of the focusing position determined in step S6, thereby changing the optical conditions of the optical system.

[0233] For example, the main control unit 211 controls the polarization controller 103 to change the polarization component of light L0 by a change amount corresponding to the correction amount of the polarization state determined in step S6, thereby changing the optical conditions of the optical system.

[0234] For example, the main control unit 211 controls the VCC drive unit 47A to change the cylindrical power or cylindrical axis angle of the VCC lens 47 by a change amount corresponding to the aberration correction amount determined in step S6, thereby changing the optical conditions of the optical system.

[0235] For example, the main control unit 211 controls the optical path length changing unit 41 or the reference drive unit 114A to move the position of the optical path length changing unit 41 (corner prism) on the optical path of the measuring light LS or the position of the corner prism 114 on the optical path of the reference light LR by the correction amount of the optical path length difference determined in step S6, thereby changing the optical conditions of the optical system.

[0236] For example, the main control unit 211 controls the moving mechanism 150 to move the position of the optical system relative to the optical axis of the eye being examined E or the position in the direction intersecting the optical axis of the optical system by the movement correction amount of the optical system determined in step S6, thereby changing the optical conditions of the optical system.

[0237] (S10: OCT scan complete?) Next, in step S9, the main control unit 211 determines whether to end the OCT scan. For example, the main control unit 211 determines whether to end the OCT scan based on the content of controlling the optical scanner 42 to perform an OCT scan on the scan area set in step S3.

[0238] When it is determined in step S10 that the OCT scan is to be ended (S10: Yes), the operation of the ophthalmic device 1 proceeds to step S11. When it is determined in step S10 that the OCT scan is not to be ended (S10: No), the operation of the ophthalmic device 1 proceeds to step S4.

[0239] (S11: Synthesized OCT image) When it is determined in step S10 that the OCT scan is to end (S10: Yes), the main control unit 211 controls the image synthesis unit 231 to align the multiple OCT images formed in step S5 to generate a synthesized image. If a synthesized image has already been generated, step S11 can be omitted.

[0240] (S12: Display) Next, in step S11, the main control unit 211, acting as a display control unit, causes the display unit 240A (or display device 3) to display the composite image generated in step S11.

[0241] In some embodiments, the main control unit 211 causes the display unit 240A to display the correction amount (adjustment amount) of the optical conditions of the optical system determined in step S6 for each scanning area.

[0242] The operation of ophthalmic device 1 is now complete (terminated).

[0243] exist Figure 12A In step S6, the OCT image formed in step S5 is processed. Figure 13A and Figure 13B The process is shown below. Before the process in step S6, the image compositing unit 231 generates a composite image based on the multiple OCT images formed in step S5.

[0244] (S21: Determine the image location) exist Figure 12A In step S6, the main control unit 211 controls the image position determination unit 232A to determine the position (drawing position) of the region of interest in the OCT image formed in step S5 in the depth direction.

[0245] For example, as described above, the image position determination unit 232A determines the centroid position in the depth direction of the OCT image, and determines the position of the region of interest in the depth direction in the OCT image based on the determined centroid position in the depth direction.

[0246] (S22: Adjust image position?) Next, the main control unit 211 determines whether the depth direction depiction position of the region of interest in the OCT image determined in step S21 should be adjusted. For example, the main control unit 211 determines whether the depth direction depiction position of the region of interest in the OCT image should be adjusted by determining whether the depth direction depiction position of the region of interest in the OCT image determined in step S21 is within a predetermined depth range.

[0247] If it is determined in step S22 that the depth direction of the depicted area of ​​interest in the OCT image should be adjusted (S22: Yes), the processing in step S6 proceeds to step S23. If it is determined in step S22 that the depth direction of the depicted area of ​​interest in the OCT image should not be adjusted (S22: No), the processing in step S6 proceeds to step S24.

[0248] (S23: Determine the correction amount for the optical path length difference) When it is determined in step S22 that the depth direction of the depicted position of the region of interest in the OCT image should be adjusted (S22: Yes), the main control unit 211 determines the correction amount of the difference in optical path length between the measuring light LS and the reference light LR.

[0249] For example, the main control unit 211 determines the correction amount for the difference in optical path length between the measuring light LS and the reference light LR based on the displacement of the depicted position in the depth direction of the region of interest in the OCT image determined in step S21 relative to a reference depth position within a predetermined depth range. That is, the main control unit 211 determines the correction amount for the difference in optical path length between the measuring light LS and the reference light LR in a manner that makes the depicted position in the depth direction of the region of interest in the OCT image determined in step S21 consistent with a reference depth position within a predetermined depth range. Examples of reference depth positions include a center position (or centroid position) within a predetermined depth range, an upper limit position within a predetermined reference range within the aforementioned depth range, and a lower limit position within a predetermined reference range within the aforementioned depth range.

[0250] (S24: Calculate image quality evaluation value) When it is determined in step S22 that the depth direction of the depicted position of the area of ​​interest in the OCT image should not be adjusted (S22: No), or in step S23, the main control unit 211 controls the image quality evaluation value calculation unit 232B to calculate the image quality evaluation value of the OCT image (synthetic image) formed in step S5.

[0251] For example, the main control unit 211 controls the image quality evaluation value calculation unit 232B to calculate the image quality evaluation value for each of the multiple OCT images formed in each scanning area in step S5.

[0252] (S25: Adjust focus position?) Next, in step S24, the main control unit 211 determines whether the focus position of the measurement light LS should be adjusted based on the image quality evaluation value calculated in step S24. In this embodiment, the main control unit 211 determines whether the focus position of 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.

[0253] For example, the main control unit 211 determines whether the focus position of the measurement light LS should be adjusted based on the comparison result between the predetermined reference image quality evaluation value and the image quality evaluation value calculated in step S24.

[0254] If it is determined in step S25 that the focus position of the measuring light LS should be adjusted (S25: Yes), the process of step S6 proceeds to step S26. If it is determined in step S25 that the focus position of the measuring light LS should not be adjusted (S25: No), the process of step S6 proceeds to step S27.

[0255] (S26: Determine the correction amount for the focus position) When it is determined in step S25 that the focus position of the measurement light LS should be adjusted (S25: Yes), the main control unit 211 determines the correction amount of the focus position of the measurement light LS.

[0256] For example, the main control unit 211 compares a predetermined reference image quality evaluation value with the image quality evaluation value calculated in step S24, 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, and determines a correction amount for the focus position of the measurement light LS for each of the multiple OCT images. In some embodiments, the main control unit 211 determines the adjustment direction of the focus position of the measurement light LS based on the displacement of the scanning area relative to the deepest part of the cross-sectional shape of the fundus Ef, and determines the correction amount of the focus position of the measurement light LS in the determined adjustment direction.

[0257] (S27: Adjust polarization state?) If it is determined in step S25 that the focus position of the measurement light LS should not be adjusted (S25: No), or proceeding to step S26, the main control unit 211 determines whether the polarization state of the light L0 or the measurement light LS from the light source unit 101 should be adjusted based on the image quality evaluation value calculated in step S24. In this embodiment, the main control unit 211 determines whether 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.

[0258] For example, the main control unit 211 determines whether the polarization state of light L0 or measurement light LS should be adjusted based on a comparison between a predetermined reference image quality evaluation value and the image quality evaluation value calculated in step S24. In some embodiments, polarization information is pre-stored in the storage unit 212. This polarization information is information that associates the comparison between the reference image quality evaluation value and the calculated image quality evaluation value with the polarization state. The main control unit 211 refers to the polarization information stored in the storage unit 212 to determine whether the polarization state of light L0 or measurement light LS should be adjusted.

[0259] If it is determined in step S27 that the polarization state of light L0 should be adjusted or light LS should be measured (S27: Yes), the process of step S6 proceeds to step S28. If it is determined in step S27 that the polarization state of light L0 should not be adjusted or light LS should not be measured (S27: No), the process of step S6 proceeds to step S29.

[0260] (S28: Correction amount to determine polarization state) When it is determined in step S27 that the polarization state of light L0 or measurement light LS should be adjusted (S27: Yes), the main control unit 211 determines the correction amount of the polarization state of light L0 or measurement light LS.

[0261] For example, the main control unit 211 compares a predetermined reference image quality evaluation value with the image quality evaluation value calculated in step S24, 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, and determines the correction amount of the polarization state of the light L0 or the measurement light LS for each of the multiple OCT images. In some embodiments, the main control unit 211 determines the adjustment direction of the polarization state of the measurement light LS of the light L0 with reference to the above polarization information, and determines the correction amount of the polarization state of the light L0 or the measurement light LS in the determined adjustment direction.

[0262] (S29: Adjusting aberrations?) Next, if it is determined in step S27 that the polarization state of light L0 or the measured light LS should not be adjusted (S27: No), or proceeding to step S28, the main control unit 211 determines whether aberration should be adjusted based on the image quality evaluation value calculated in step S24. In this embodiment, the main control unit 211 determines whether aberration 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.

[0263] For example, the main control unit 211 determines whether aberrations should be adjusted based on a comparison between a predetermined reference image quality evaluation value and the image quality evaluation value calculated in step S24. In some embodiments, aberration information is pre-stored in the storage unit 212. This aberration information is information that associates the comparison between the reference image quality evaluation value and the calculated image quality evaluation value with aberrations. The main control unit 211 refers to the aberration information stored in the storage unit 212 to determine whether aberrations should be adjusted.

[0264] If it is determined in step S29 that the polarization state of light L0 or light LS should be adjusted (S29: Yes), the processing of step S6 proceeds to step S30. If it is determined in step S29 that the aberration should not be adjusted (S29: No), the processing of step S6 proceeds to step S31.

[0265] (S30: Determine the aberration correction amount) When it is determined in step S29 that the aberration should be adjusted (S29: Yes), the main control unit 211 determines the aberration correction amount.

[0266] For example, the main control unit 211 compares a predetermined reference image quality evaluation value with the image quality evaluation value calculated in step S24, 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, and determines an aberration correction amount for each of the multiple OCT images. In some embodiments, the main control unit 211 determines the adjustment direction of the polarization state of the measurement light LS of light L0 with reference to the above-mentioned aberration information, and determines the aberration correction amount in the determined adjustment direction.

[0267] (S31: Adjust the alignment?) Next, in step S30, if it is determined in step S29 that aberration should not be adjusted (S29: No), or in step S30, the main control unit 211 determines whether the alignment position of the optical system relative to the eye being examined E should be adjusted based on the image quality evaluation value calculated in step S24.

[0268] In some implementations, the main control unit 211 determines whether the alignment position should be adjusted for each of the plurality of OCT images based on the image quality evaluation value calculated for each of the plurality of OCT images in step S24. For example, the main control unit 211 determines whether the alignment position should be adjusted based on a comparison between a predetermined reference image quality evaluation value and the image quality evaluation value calculated in step S24.

[0269] In some embodiments, the main control unit 211 determines whether the alignment position should be adjusted based on the depicted position of the region of interest in the OCT image determined by the image position determination unit 232A. For example, the main control unit 211 determines whether the alignment position should be adjusted based on the displacement of the position of the region of interest in the OCT image relative to a predetermined reference position, as determined by the image position determination unit 232A.

[0270] If it is determined in step S31 that the alignment position should be adjusted (S31: Yes), the processing of step S6 proceeds to step S32. If it is determined in step S31 that the alignment position should not be adjusted (S31: No), the processing of step S6 ends (terminates).

[0271] (S32: Determine the movement correction amount of the optical system) When it is determined in step S31 that the alignment position should be adjusted (S32: Yes), the main control unit 211 determines the amount of movement correction of the optical system.

[0272] For example, the main control unit 211 compares a predetermined reference image quality evaluation value with the image quality evaluation value calculated in step S24, 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, and determines the motion correction amount of the optical system. In some embodiments, the main control unit 211 determines the motion correction amount of the optical system per scanning area. In some embodiments, the main control unit 211 determines a single motion correction amount of the optical system in a manner that maximizes the statistical value (e.g., average value) of the image quality evaluation value.

[0273] For example, the main control unit 211 determines the amount of motion correction of the optical system based on the displacement of the position of the region of interest in the OCT image relative to a predetermined reference position, which is determined by the image position determination unit 232A.

[0274] When it is determined in step S31 that the alignment position should not be adjusted (S31: No), or following step S32, the processing of step S6 ends (terminates).

[0275] Furthermore, the order in which the optical conditions of the optical system in the implementation method are changed is not limited to... Figure 13A and Figure 13B The order of changes is shown. Furthermore, in the embodiment, the optical conditions of the changed optical system only need to include... Figure 13A and Figure 13B Any one or more of the optical conditions shown are acceptable.

[0276] As explained above, according to the first embodiment, when an OCT scan is performed on the examined eye E using a combination of low-speed and high-speed scanning, the cross-sectional structure of the examined eye E is substantially estimated based on the OCT data or OCT image obtained through the previously performed high-speed scan. Based on the estimated cross-sectional structure, the optical conditions of the optical system are changed synchronously with the period of the low-speed scan. As a result, without pre-scanning, when the examined eye E is photographed at a wide angle, an image of the examined eye E can be acquired with good image quality.

[0277] <Second Implementation> In the first embodiment, the case where a VCC lens 47 is provided in the ophthalmic device as an aberration correction device is described, but the structure of the embodiment is not limited to this. For example, the ophthalmic device of the embodiment may include a wavefront aberration correction optical system as an aberration correction device.

[0278] The following description focuses on the differences between the structure of the second embodiment and that of the first embodiment.

[0279] Figure 14 An example of the structure of the optical system of the ophthalmic device 1a according to the second embodiment is shown. Figure 14 In, with Figure 1 The same reference numerals are used for the same parts, and descriptions are omitted where appropriate.

[0280] The optical system structure of the ophthalmic device 1a in the second embodiment differs from that of the ophthalmic device 1 in the first embodiment in that: a fundus camera unit 2a is provided instead of a fundus camera unit 2, and a computation control unit 200a is provided instead of a computation control unit 200.

[0281] The difference between the structure of fundus camera unit 2a and fundus camera unit 2 is that wavefront aberration correction optical system 70 is used instead of VCC lens 47. The difference between the operation control unit 200a and operation control unit 200 is that the wavefront aberration correction optical system 70 is used instead of VCC lens 47.

[0282] 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.

[0283] exist Figure 14 In this configuration, the beam splitter 71 and the compensating optical element 72 are disposed between the collimating lens unit 40 and the optical path length changing unit 41. The compensating optical element 72 is disposed between the beam splitter 71 and the optical path length changing unit 41.

[0284] Beam splitter 71 branches the return light of the measurement light LS into light directed towards the collimating lens unit 40 and light directed towards the relay lens 73. Beam splitter 71 can change the branching ratio of these lights. For example, when the compensation optics 72 described later is controlled (e.g., for prediction), the return light of the measurement light LS is branched into two beams with a branching ratio of "50:50". Furthermore, when the compensation optics 72 is not controlled (e.g., for formal measurement), the return light of the measurement light LS can be branched into two beams with a branching ratio of "90:10" to increase the amount of light directed towards the collimating lens unit 40.

[0285] The compensation optical element 72 may be, for example, a deformable phase plate (DPP). The compensation optical element 72 is an optical element that can locally change the wavefront phase of the light to be transmitted.

[0286] A relay lens 73, a lens array 74, and a wavefront sensor 75 are arranged in the reflection direction of the beam splitter 71. Each of the compensating optical element 72 and the lens array 74 is arranged at or near a position optically conjugate to the pupil of the examined eye E (pupil conjugate position).

[0287] Beam splitter 71 allows the measurement light LS from collimating lens unit 40 to pass through and be guided to compensating optics 72, and guides the return light of the measurement light LS from the examined eye E, which passes through compensating optics 72, to relay lens 73. Compensating optics 72 at least corrects the wavefront aberration of the return light of the measurement light LS. The return light of the measurement light LS, guided to relay lens 73, is then guided to lens array 74.

[0288] The lens array 74 includes multiple lenses arranged in an array, generating multiple focused beams from the light passing through the relay lens 73. The multiple focused beams generated by the lens array 74 illuminate the sensor surface of the wavefront sensor 75. The wavefront sensor 75 can be, for example, a CMOS image sensor or a CCD image sensor.

[0289] Based on the detection results of multiple beams obtained by the wavefront sensor 75, the wavefront of the light passing through the compensation optics 72 can be locally altered. Thus, the compensation optics 72 can correct the wavefront aberration of the return light from the measurement light LS originating from the examined eye E.

[0290] Figure 15 A block diagram showing a structural example of the processing system of the ophthalmic device 1a according to the second embodiment is provided. Figure 15 In, with Figure 4 The same reference numerals are used for the same parts, and descriptions are omitted where appropriate.

[0291] The difference between the processing system of the ophthalmic device 1a in the second embodiment and the processing system of the ophthalmic device 1 in the first embodiment is that the wavefront aberration correction optical system 70 is used instead of the VCC lens 47, and a control unit 210a is provided instead of the control unit 210.

[0292] The control unit 210a includes a main control unit 211a and a storage unit 212a. The difference between the control unit 210a and the control unit 210 is that the control wavefront aberration correction optical system 70 replaces the VCC drive unit 47A.

[0293] That is, according to the second embodiment, by controlling the wavefront aberration correction optical system 70, the aberration correction components can be changed, and the optical conditions of the optical system can be changed.

[0294] The wavefront aberration correction optical system 70 is an example of an "aberration correction device" in the embodiment. The optical system, optical path length changing unit 41, OCT focusing lens 45, and wavefront aberration correction optical system 70 (interference optical system) included in the OCT unit 100 are examples of an "optical system" in the embodiment.

[0295] <Variation Example> In the first or second embodiment, an ammonite scan was described as an example of a scan that combines low-speed and high-speed scanning, but the embodiments are not limited to this.

[0296] Figure 16 An explanatory diagram showing an XY scan of a first variation of the first embodiment or the second embodiment.

[0297] The first variation of the XY scan also involves a scanning mode in which the scanning center position of the high-speed scan moves along the scanning pattern (scan trajectory) of the low-speed scan, and then performs one or more high-speed scans sequentially with a predetermined scanning pattern, using the moved scanning center position as a reference. In this variation of the XY scan, the high-speed scan is a circular scan, the low-speed scan is an elliptical scan, and the sequentially performed circular scans are performed in a manner that intersects with the scanning pattern of the previous circular scan. That is, the circular scans are performed sequentially in a manner that makes the scanning patterns of two adjacent circular scans intersect.

[0298] exist Figure 16 The image shows schematically the scanning pattern Lsc1 for low-speed scanning and schematically the scanning pattern HS1 for high-speed scanning. n (n is an integer greater than or equal to 4), HS1 n-1、 HS1 n-2、 HS1 n-3 .

[0299] Similar to ammonite scanning, XY scanning combines low-speed and high-speed scanning, allowing for easy control of scanning the eye E from various scanning directions. In particular, high-density scanning can be performed in the periphery near the center of XY scanning (the scanning center position of low-speed scanning), thereby enabling easy control of scanning a wide-angle area including the region of interest.

[0300] According to this modified example, by scanning the examined eye E with XY scanning, regardless of the cross-sectional structure of the examined eye E, it is possible to measure or photograph the examined eye E with higher image quality and wider angle.

[0301] Figure 17 An explanatory diagram showing a three-dimensional vertical (3D(V)) scan of a second variation of the first or second embodiment.

[0302] The second variation of 3D(V) scanning also involves moving the scanning center position of the high-speed scan along the scanning pattern (scanning trajectory) of the low-speed scan while using the moved scanning center position as a reference to perform a high-speed scan more than once with a predetermined scanning pattern. In this variation of 3D(V) scanning, the high-speed scan is a vertical line scan, and the low-speed scan is a horizontal line scan.

[0303] exist Figure 17The image shows schematically the scanning pattern Lsc2 for low-speed scanning and schematically the scanning pattern HS2 for high-speed scanning. n (n is an integer greater than or equal to 4), HS2 n-1、 HS2 n-2、 HS2 n-3 .

[0304] Similar to ammonite scanning, 3D(V) scanning, by combining low-speed and high-speed scanning, allows for simple control of scanning the examined eye E from various scanning directions. In particular, it enables scanning of the examined eye E with uniform density, thereby allowing for simple control of scanning a wide-angle area including the region of interest.

[0305] According to this variation, by scanning the examined eye E with 3D (V) scanning, regardless of the cross-sectional structure of the examined eye E, it is possible to measure or photograph the examined eye E with a wider angle and higher image quality.

[0306] Figure 18 An explanatory diagram showing a three-dimensional horizontal (3D(H)) scan of a third variation of the first or second embodiment.

[0307] The third variation of 3D(H) scanning also involves moving the scanning center position of the high-speed scan along the scanning pattern (scanning trajectory) of the low-speed scan while using the moved scanning center position as a reference to perform a high-speed scan more than once with a prescribed scanning pattern. In this variation of 3D(H) scanning, the high-speed scan is a horizontal line scan, and the low-speed scan is a vertical line scan.

[0308] exist Figure 18 The image shows schematically the scanning pattern Lsc3 for low-speed scanning and schematically the scanning pattern HS3 for high-speed scanning. n (n is an integer greater than or equal to 4), HS3 n-1 HS3 n-2 HS3 n-3 .

[0309] Similar to ammonite scanning, 3D(H) scanning, by combining low-speed and high-speed scanning, allows for simple control of scanning the examined eye E from various scanning directions. In particular, it enables scanning of the examined eye E with uniform density, thereby allowing for simple control of scanning a wide-angle area including the region of interest.

[0310] According to this variation, by scanning the examined eye E with 3D (H) scanning, the examined eye E can be measured or photographed with a wider angle and higher image quality, regardless of the cross-sectional structure of the examined eye E.

[0311] [effect] This describes the implementation of the OCT device, its control method, and its procedure.

[0312] The first embodiment is an OCT device (ophthalmic device 1, 1a) including an optical system (optical system included in OCT unit 100, optical path length changing unit 41, OCT focusing lens 45 and VCC lens 47 (or wavefront aberration correction optical system 70), interferometric optical system) and a control unit (210, 210a, main control unit 211, main control unit 211a). The optical system is configured to be able to change optical conditions (focus position of measurement light LS, polarization component of measurement light LS, aberration correction component, optical path length difference between measurement light LS and reference light LR, or position of the optical system relative to the examined eye E), and is configured to include a light scanner (42), and to acquire OCT data of the examined eye E by scanning the measured object (examined eye E) with measurement light (LS) using the light scanner. The control unit controls the light scanner to scan the measured object with measurement light along the high-speed scanning axis using a reference position that moves along the low-speed scanning axis as a reference. The control unit changes the optical conditions in sync with the period of the low-speed scan along the low-speed scan axis.

[0313] In this manner, since the optical conditions of the optical system can be changed synchronously with the low-speed scanning cycle using the OCT data obtained during scanning, it is possible to acquire an image of the object under test with good image quality without causing image quality degradation due to scanning position shifts during scanning. In particular, when photographing the object under test with a wide angle, an image of the object under test can be acquired with good image quality without performing a pre-scan.

[0314] In a second embodiment, according to the first embodiment, the optical system includes an interferometric optical system (the optical system included in the OCT unit 100, the optical path length changing unit 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 changing component (optical path length changing unit 41, or corner prism 114 and reference drive unit 114A). The interferometric optical system splits the light (L0) from the light source (light source unit 101) into a measurement light and a reference light (LR). The measurement light, which has passed through the measurement optical path configured with one or more optical elements (OCT focusing lens 45, corner prism 114, optical path length changing unit 41, polarization controller 103), is projected onto the object to be measured, and the interference light (LC) between the return light from the object to be measured and the reference light that has passed through the reference optical path is detected. The optical path length difference changing component 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 optical elements and the optical path length difference changing components.

[0315] In this manner, OCT of the object under test is performed by changing the optical conditions of the optical system by controlling at least one of one or more optical elements and an optical path length difference changing component. Therefore, regardless of the cross-sectional shape of the object under test, an image of the object under test can be acquired with good image quality.

[0316] In a third embodiment, according to the second embodiment, 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).

[0317] In this manner, by controlling at least one of the optical elements, including a focusing lens or aberration correction device, and at least one of the optical path length difference alteration components, the optical conditions of the optical system can be changed to perform OCT on the object under test without pre-scanning. Therefore, regardless of the cross-sectional shape of the object under test, an image of the object under test can be acquired with good image quality, and the measurement time (image capture time) can be shortened.

[0318] In the fourth embodiment, according to the second or third embodiment, an image forming unit (220) and an image quality evaluation value calculation unit (232B) are included. The image forming unit forms an image of the object being measured based on OCT data. The image quality evaluation value calculation unit calculates an evaluation value of the image quality of the object being measured. The control unit controls one or more optical elements based on the evaluation value.

[0319] In this way, since the optical conditions of the optical system are changed based on the image quality evaluation value of the object being measured, the image of the object being measured can be acquired with good image quality with simple control and high precision, regardless of the cross-sectional shape of the object being measured.

[0320] In the fifth embodiment, according to any one of the first to third embodiments, a moving mechanism (150) is included to move the optical system relative to the object being measured. The control unit changes the optical conditions of the optical system by controlling the moving mechanism.

[0321] In this manner, OCT of the object being measured is performed by changing the optical conditions of the optical system by moving it relative to the object being measured. Therefore, regardless of the cross-sectional shape of the object, images of the object can be acquired with good image quality, thus shortening the measurement time (image capture time).

[0322] In a sixth embodiment, according to either the second or third embodiment, an image forming unit (220) is included. The image forming unit forms an image of the object being measured based on OCT data. The control unit controls the optical path length difference changing unit based on the position of the object being measured in the image.

[0323] In this way, by using the OCT data obtained during scanning and changing the optical path length difference between the measurement light and the reference light in sync with the low-speed scanning cycle, it is possible to acquire an image of the object being measured with good image quality.

[0324] In the seventh embodiment, according to any one of the first to third embodiments, the high-speed scanning axis is a circular scanning axis and the low-speed scanning axis is a spiral scanning axis.

[0325] In this way, it is possible to scan at high density in a short time in the area near the center (the scanning center position of low-speed scanning), and to spend more time scanning at low density as you move away from the center. This allows for easy control over acquiring images of the object being measured with good image quality in a wide-angle area that includes the area of ​​interest.

[0326] The eighth embodiment is a control method for an OCT device (ophthalmic device 1, 1a), which includes an optical system (optical system included in OCT unit 100, optical path length changing unit 41, OCT focusing lens 45 and VCC lens 47 (or wavefront aberration correction optical system 70), and an interference optical system). This optical system is configured to change optical conditions (focusing position of the measurement light LS, polarization component of the measurement light LS, aberration correction component, optical path length difference between the measurement light LS and the reference light LR, or the position of the optical system relative to the examined eye E), and includes a light scanner (42). It is configured to acquire OCT data of the examined eye E by scanning the measured object (examined eye E) with the measurement light (LS) using the light scanner. The control method for the OCT device includes a control step and an optical condition changing step. In the control step, the light scanner is controlled such that a reference position moved along the low-speed scanning axis is used as a reference to scan the measured object along the high-speed scanning axis with the measurement light. In the optical condition changing step, the optical conditions are changed synchronously with the period of the low-speed scan along the low-speed scanning axis.

[0327] In this manner, since the optical conditions of the optical system can be changed synchronously with the low-speed scanning cycle using the OCT data obtained during scanning, it is possible to acquire an image of the object under test with good image quality without causing image quality degradation due to scanning position shifts during scanning. In particular, when photographing the object under test with a wide angle, an image of the object under test can be acquired with good image quality without performing a pre-scan.

[0328] In the ninth embodiment, according to the eighth embodiment, the optical system includes an interferometric optical system (the optical system included in the OCT unit 100, the optical path length changing unit 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 changing component (optical path length changing unit 41, or corner prism 114 and reference drive unit 114A). The interferometric optical system splits the light (L0) from the light source (light source unit 101) into a measurement light and a reference light (LR). The measurement light, which has passed through the measurement optical path configured with one or more optical elements (OCT focusing lens 45, corner prism 114, optical path length changing unit 41, polarization controller 103), is projected onto the object to be measured, and the interference light (LC) between the return light from the object to be measured and the reference light that has passed through the reference optical path is detected. The optical path length difference changing component changes the difference between the optical path length of the measurement light and the optical path length of the reference light. The optical condition change step changes the optical conditions of the optical system by controlling at least one of one or more optical elements and optical path length difference change components.

[0329] In this manner, by controlling at least one of one or more optical elements and an optical path length difference alteration component, the optical conditions of the optical system are changed to perform OCT on the object being measured. Thus, regardless of the cross-sectional shape of the object being measured, an image of the object can be acquired with good image quality.

[0330] In the tenth embodiment, according to the ninth embodiment, 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).

[0331] In this manner, by controlling at least one of the optical elements, including a focusing lens or aberration correction device, and at least one of the optical path length difference alteration components, the optical conditions of the optical system can be changed to perform OCT on the object being measured without pre-scanning. Therefore, regardless of the cross-sectional shape of the object being measured, an image of the object can be acquired with good image quality, thus shortening the measurement time (image capture time).

[0332] In the eleventh embodiment, according to the ninth or tenth embodiment, it includes an image forming step and an image quality evaluation value calculation step. In the image forming step, an image of the object being measured is formed based on OCT data. In the image quality evaluation value calculation step, an image quality evaluation value for the image of the object being measured is calculated. In the optical condition modification step, one or more optical elements are controlled based on the evaluation value.

[0333] In this way, by changing the optical conditions of the optical system based on the image quality evaluation value of the object being measured, images of the object being measured can be acquired with good image quality with simple control and high precision, regardless of the cross-sectional shape of the object being measured.

[0334] In the twelfth embodiment, according to any one of the eighth to tenth embodiments, the OCT device includes a moving mechanism (150) that moves the optical system relative to the object being measured. In the optical condition changing step, the optical conditions of the optical system are changed by controlling the moving mechanism.

[0335] In this manner, the optical conditions of the optical system are changed by moving the optical system relative to the object being measured, thereby performing OCT on the object. As a result, regardless of the cross-sectional shape of the object, an image of the object can be acquired with good image quality, and the measurement time (image capture time) can be shortened.

[0336] In the thirteenth embodiment, according to the ninth or tenth embodiment, an image forming step is included to form an image of the object being measured based on OCT data. In the optical condition changing step, the optical path length difference changing component is controlled based on the position of the object being measured in the image.

[0337] In this way, by using the OCT data obtained during scanning to change the optical path length difference between the measurement light and the reference light in sync with the low-speed scanning cycle, it is possible to acquire an image of the object being measured with good image quality.

[0338] In the fourteenth embodiment, according to any one of the eighth to tenth embodiments, the high-speed scanning axis is a circular scanning axis and the low-speed scanning axis is a spiral scanning axis.

[0339] In this way, it is possible to scan at high density in a short time in the area near the center (the scanning center position of low-speed scanning), and to spend more time scanning at low density as you move away from the center. This allows for easy control over acquiring images of the object being measured with good image quality in a wide-angle area that includes the area of ​​interest.

[0340] The fifteenth embodiment is a program for causing a computer to execute the steps of the control method for the OCT device described in any one of the eighth to tenth embodiments.

[0341] In this manner, since the optical conditions of the optical system can be changed synchronously with the low-speed scanning cycle using the OCT data obtained during scanning, it is possible to acquire an image of the object under test with good image quality without causing image quality degradation due to scanning position shifts during scanning. In particular, when photographing the object under test with a wide angle, an image of the object under test can be acquired with good image quality without performing a pre-scan.

[0342] The structure described above is merely one example for preferably implementing the present invention. Therefore, any modifications (omissions, substitutions, additions, etc.) within the scope of the present invention can be appropriately implemented. For example, the appropriate structure can be selected depending on the purpose. Furthermore, with the appropriate structure, effects that are obvious to those skilled in the art and effects described in this specification can be obtained.

[0343] (Explanation of reference numerals in the attached image) 1.1a Ophthalmic device 3 Display devices 41 Optical Path Length Change Section 45 OCT focusing lens 47 VCC lens 47A VCC Drive Unit 70 Wavefront aberration correction optical system 100 OCT units 103, 118 Polarization Controller 114 Corner Prism 114A Reference Drive Unit 200, 200a Operation and Control Unit 210, 210a Control Department 211, 211a Main Control Unit 212, 212a Storage Section 220 Image forming unit 230 Data Processing Department 231 Image Composition Unit 232 Analysis Department 232A Image Position Determination Unit 232B Image Quality Evaluation Value Calculation Department 240A Display Unit E The examined eye SAR1 central region SAR2 intermediate region SAR3 surrounding area LC interference light LR reference light LS measures light.

Claims

1. An optical coherence tomography (OCT) device, comprising: An optical system is configured to change optical conditions, includes a light scanner, and is configured to acquire optical coherence tomography data of the test object by scanning the test object with measurement light using the light scanner. as well as The control unit controls the optical scanner to scan the object under test along the high-speed scanning axis using the measurement light, with the reference position moved along the low-speed scanning axis as a reference. The control unit changes the optical conditions in sync with the period of the low-speed scan along the low-speed scan axis.

2. The optical coherence tomography apparatus according to claim 1, characterized in that, The optical system includes: An interferometric optical system splits light from a light source into a measurement beam and a reference beam. The measurement beam, having passed through a measurement optical path equipped with one or more optical elements, is projected onto the object under test. The system detects the interference between the return light from the object under test and the reference beam that has passed through the reference optical path. The optical path length difference changing component changes the difference between the optical path length of the measuring 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 more than one optical element and the optical path length difference changing component.

3. The optical coherence tomography apparatus according to claim 2, characterized in that, The one or more optical elements include focusing lenses or aberration correction devices.

4. The optical coherence tomography apparatus according to claim 2 or 3, characterized in that, The optical coherence tomography device includes: The image forming unit forms an image of the object being measured based on the optical coherence tomography data; and The image quality evaluation value calculation unit calculates the image quality evaluation value of the object being measured. The control unit controls the one or more optical elements based on the evaluation value.

5. The optical coherence tomography apparatus according to any one of claims 1 to 3, characterized in that, The optical coherence tomography apparatus includes a movement mechanism that moves the optical system relative to the object being measured. The control unit changes the optical conditions of the optical system by controlling the moving mechanism.

6. The optical coherence tomography apparatus according to claim 2 or 3, characterized in that, The optical coherence tomography (OCT) apparatus includes an image forming unit that forms an image of the object being measured based on the OCT data. The control unit controls the optical path length difference changing component based on the position of the object being measured in the image.

7. The optical coherence tomography apparatus according to any one of claims 1 to 3, characterized in that, The high-speed scanning axis is a circular scanning axis. The low-speed scanning axis is a spiral scanning axis.

8. A control method for an optical coherence tomography (OCT) device, The optical coherence tomography (OCT) apparatus includes an optical system configured to modify optical conditions, and includes a light scanner. The OCT apparatus is configured to acquire OCT data of the measured object by scanning the measured object with measurement light using the light scanner. The control method includes: The control steps involve controlling the optical scanner to scan the object to be measured along the high-speed scanning axis using the measurement light, with the reference position moved along the low-speed scanning axis as a reference. as well as The optical condition changing step involves changing the optical conditions in sync with the period of the low-speed scan along the low-speed scan axis.

9. The control method for the optical coherence tomography (OCT) device according to claim 8, characterized in that, The optical system includes: An interferometric optical system splits light from a light source into a measurement beam and a reference beam. The measurement beam, having passed through a measurement optical path equipped with one or more optical elements, is projected onto the object under test. The system detects the interference between the return light from the object under test and the reference beam that has passed through the reference optical path. The optical path length difference changing component changes the difference between the optical path length of the measuring light and the optical path length of the reference light. In the optical condition changing step, the optical conditions of the optical system are changed by controlling at least one of the more than one optical element and the optical path length difference changing component.

10. The control method for the optical coherence tomography (OCT) device according to claim 9, characterized in that, The one or more optical elements include focusing lenses or aberration correction devices.

11. The control method for the optical coherence tomography apparatus according to claim 9 or 10, characterized in that, The control method includes: The image formation step involves forming an image of the object under test based on the optical coherence tomography data; and The image quality evaluation value calculation steps involve calculating the image quality evaluation value of the object being measured. In the optical condition change step, one or more optical elements are controlled based on the evaluation value.

12. The control method of the optical coherence tomography apparatus according to any one of claims 8 to 10, characterized in that, The optical coherence tomography apparatus includes a movement mechanism that moves the optical system relative to the object being measured. In the optical condition changing step, the optical conditions of the optical system are changed by controlling the moving mechanism.

13. The control method for the optical coherence tomography apparatus according to claim 9 or 10, characterized in that, The control method includes an image forming step that forms an image of the object being measured based on the optical coherence tomography data. In the optical condition change step, the optical path length difference change component is controlled based on the position of the object being measured in the image.

14. The control method for the optical coherence tomography apparatus according to any one of claims 8 to 10, characterized in that, The high-speed scanning axis is a circular scanning axis. The low-speed scanning axis is a spiral scanning axis.

15. A program, characterized in that, The steps of the control method for the optical coherence tomography apparatus according to any one of claims 8 to 10 are made to be executed by computer.

Images