Ophthalmic apparatus, method for controlling ophthalmic apparatus, and program

Abstract

To provide a new technology to adjust an imaging condition accurately even in the case where the speed of a light source is accelerated.SOLUTION: An ophthalmologic apparatus includes an interference optical system, an optical scanner control unit, and a correction control unit. The interference optical system divides the light from a light source into measurement light and reference light, irradiates an eye to be examined with the measurement light through an astigmatism correction optical member and the optical scanner, and detects interference light between return light of the measurement light from the eye to be examined and the reference light. The optical scanner control unit controls the optical scanner according to a first scan pattern or a second scan pattern. The correction control unit executes correction control for controlling the astigmatism correction optical member on the basis of a result of the detection of the interference light acquired by deflecting the measurement light according to the first scan pattern. An image forming unit forms an image of the eye to be examined according to a result of the detection of interference light acquired by deflecting the measurement light according to the second scan pattern after executing the correction control.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] In recent years, optical coherence tomography (OCT), which uses a light beam from a laser or other source to form images that represent the surface or internal morphology of an object under measurement, has been attracting attention. Unlike X-ray computed tomography (CT), OCT is non-invasive, and is therefore expected to be particularly useful in the medical and biological fields. For example, in the field of ophthalmology, devices that form images of the fundus and cornea have been put to practical use.

[0003] In such devices, imaging conditions (measurement conditions) are adjusted before OCT is performed to obtain an image optimal for observing the shape of the object to be measured (for example, Patent Document 1 and Patent Document 2). The adjustment of imaging conditions includes adjustment of the position of the imaging region, focus adjustment, and polarization adjustment. In particular, Patent Document 2 discloses a method for adjusting imaging conditions by performing a raster scan in a time shorter than the time required for the raster scan performed during imaging. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2016-022312 [Patent Document 2] International Publication No. 2016 / 002740 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, as light sources have become faster, cases have begun to emerge in which the operating speed of the optical scanner used to scan the imaging area in OCT becomes a bottleneck. As light sources become faster, it becomes increasingly difficult to adjust imaging conditions with high precision in raster scans, which have long scanning times.

[0006] The present invention has been made in consideration of these circumstances, and one of its purposes is to provide a new technology for adjusting the shooting conditions with high precision even when the light source is faster. [Means for solving the problem]

[0007] A first aspect of some embodiments is an ophthalmic device including an astigmatism correction optical element and an optical scanner, which splits light from a light source into measurement light and reference light, irradiates the measurement light onto a test eye via the astigmatism correction optical element and the optical scanner, and detects interference light between return light of the measurement light from the test eye and the reference light, an optical scanner control unit that controls the optical scanner to deflect the measurement light in horizontal and vertical directions in a plane perpendicular to the optical axis of the interference optical element, and a correction control unit that controls the astigmatism correction optical element to correct astigmatism based on the detection result of the interference light obtained by the interference optical system.

[0008] A second aspect of some embodiments is the first aspect, which includes an analysis unit that analyzes the detection results of the interference light, and the correction control unit controls the astigmatism correction optical element based on the analysis results obtained by the analysis unit.

[0009] A third aspect of some embodiments is the second aspect, further comprising an image forming unit that forms an image of the test eye based on the detection results of the interference light, wherein the analysis unit analyzes each of a plurality of divided images obtained by dividing the image in a direction intersecting the A-scan direction, and the correction control unit controls the astigmatism correction optical element based on a plurality of analysis results for the plurality of divided images.

[0010] In a fourth aspect of some embodiments, in the third aspect, the analysis unit calculates an evaluation value corresponding to the analysis result for each divided image, and the correction control unit controls the astigmatism correction optical element based on a statistical value of multiple evaluation values ​​for the multiple divided images.

[0011] A fifth aspect of some embodiments is the fourth aspect, further including a first display control unit that causes a display unit to display the evaluation value or the statistical value calculated by the analysis unit.

[0012] In a sixth aspect of some embodiments, in any of the third to fifth aspects, the optical scanner control unit controls the astigmatism correction optical element based on the detection result of the interference light obtained by the interference optical system by controlling the optical scanner to scan a first scan range of the test eye with the measurement light, and then controls the optical scanner to scan a second scan range containing the first scan range with the measurement light, and the image forming unit forms an image of the test eye based on the detection result of the interference light obtained by scanning the second scan range with the measurement light.

[0013] In a seventh aspect of some embodiments, in the sixth aspect, the optical scanner control unit corrects the position of the second scan range based on tracking information obtained by tracking the interference optical system with respect to the movement of the test eye, and controls the optical scanner to scan the corrected second scan range with the measurement light.

[0014] An eighth aspect of some embodiments includes, in the sixth or seventh aspect, a second display control unit that causes a display means to display an image of the subject's eye formed based on the detection result of the interference light obtained by scanning the second scan range with the measurement light.

[0015] A ninth aspect of some embodiments is that, in any of the first to eighth aspects, the interference optical system includes a focus position changing member that is arranged in the optical path of the measurement light and is capable of changing the focal position of the measurement light, and the correction control unit controls the focus position changing member based on the detection result of the interference light obtained by the interference optical system.

[0016] A tenth aspect of some embodiments is that, in any of the first to ninth aspects, the interference optical system includes an optical path length changing member that is arranged in the optical path of the measurement light or the optical path of the reference light and changes the optical path length difference between the measurement light and the reference light, the optical scanner control unit controls the optical scanner to deflect the measurement light in a direction intersecting the optical axis of the interference optical system, and the correction control unit controls the optical path length changing member based on a detection result of the interference light obtained by the interference optical system.

[0017] An eleventh aspect of some embodiments is that, in any of the first to tenth aspects, the interference optical system includes a polarization state changing member that is arranged in the optical path of the measurement light or the optical path of the reference light and changes the polarization state of the measurement light or the polarization state of the reference light, the optical scanner control unit controls the optical scanner to deflect the measurement light in a direction intersecting the optical axis of the interference optical system, and the correction control unit controls the polarization state changing member based on the detection result of the interference light obtained by the interference optical system.

[0018] In a twelfth aspect of some embodiments, in any one of the first to eleventh aspects, the astigmatism correction optical member is capable of changing a cylindrical power and a cylindrical axis angle.

[0019] In a thirteenth aspect of some embodiments, in the twelfth aspect, the astigmatism correction optical element includes a variable cross cylinder lens.

[0020] A fourteenth aspect of some embodiments is the twelfth or thirteenth aspect, further including a third display control unit that causes a display unit to display at least one of the cylindrical power and the cylindrical axis angle.

[0021] In the 15th aspect of some embodiments, in any one of the 1st to 14th aspects, the optical scanner control unit deflects the measurement light in the horizontal direction and the vertical direction by controlling the optical scanner so as to deflect the measurement light in a circular shape.

[0022] In the 16th aspect of some embodiments, in the 15th aspect, when the diffraction limit is r, the diameter of the circular scan line in the eye to be examined is R, and the number of A lines in the scan line is N, R×π / N < r is satisfied.

[0023] The 17th aspect of some embodiments includes an aberration correction optical member and an optical scanner, splits the light from the light source into measurement light and reference light, irradiates the measurement light on the eye to be examined through the aberration correction optical member and the optical scanner, and is an ophthalmic device control method including an interference optical system that detects interference light between the return light of the measurement light from the eye to be examined and the reference light. The control method of the ophthalmic device includes a first control step of controlling the optical scanner so as to deflect the measurement light in the horizontal direction and the vertical direction in a plane perpendicular to the optical axis of the interference optical system, and a second control step of controlling the aberration correction optical member so as to correct the aberration based on the detection result of the interference light obtained by the interference optical system by irradiating the measurement light deflected in the first control step on the eye to be examined.

[0024] The 18th aspect of some embodiments includes an analysis step of analyzing the detection result of the interference light in the 17th aspect, and the second control step controls the aberration correction optical member based on the analysis result obtained in the analysis step.

[0025] A 19th aspect of some embodiments is the 18th aspect, which includes a first image formation step of forming an image of the test eye based on the detection results of the interference light, wherein the analysis step analyzes each of a plurality of divided images obtained by dividing the image in a direction intersecting the A-scan direction, and the second control step controls the astigmatism correction optical element based on a plurality of analysis results corresponding to the plurality of divided images.

[0026] In a 20th aspect of some embodiments, in the 19th aspect, the analysis step calculates an evaluation value corresponding to the analysis result for each divided image, and the second control step controls the astigmatism correction optical element based on a statistical value of the evaluation values ​​for the plurality of divided images.

[0027] A twenty-first aspect of some embodiments is the twentieth aspect, further including a first display control step of causing a display unit to display the evaluation value or the statistical value calculated in the analyzing step.

[0028] A 22nd aspect of some embodiments, in any of the 17th to 21st aspects, includes a third control step in which, in the second control step, after controlling the astigmatism correction optical element based on the detection result of the interference light obtained by scanning a first scan range of the test eye with the measurement light in the first control step, the optical scanner is controlled to scan a second scan range containing the first scan range with the measurement light, and a second image formation step in which an image of the test eye is formed based on the detection result of the interference light obtained by scanning the second scan range with the measurement light in the third control step.

[0029] In a 23rd aspect of some embodiments, in the 22nd aspect, the second control step corrects the position of the second scan range based on tracking information obtained by tracking the interference optical system with respect to the movement of the test eye, and controls the optical scanner to scan the corrected second scan range with the measurement light.

[0030] A 24th aspect of some embodiments, in the 22nd or 23rd aspect, includes a second display control step of causing a display means to display an image of the test eye formed based on the detection result of the interference light obtained by scanning the second scan range with the measurement light.

[0031] In a 25th aspect of some embodiments, in any of the 17th to 24th aspects, the interference optical system includes a focus position changing member that is arranged in the optical path of the measurement light and is capable of changing the focal position of the measurement light, and includes a fourth control step that controls the focus position changing member based on the detection result of the interference light obtained by the interference optical system.

[0032] In a 26th aspect of some embodiments, in any of the 17th to 25th aspects, the interference optical system includes an optical path length changing member that is arranged in the optical path of the measurement light or the optical path of the reference light and changes the optical path length difference between the measurement light and the reference light, and includes a fifth control step of controlling the optical scanner to deflect the measurement light in a direction intersecting the optical axis of the interference optical system, and a sixth control step of controlling the optical path length changing member based on a detection result of the interference light obtained by the interference optical system by irradiating the measurement light deflected in the fifth control step onto the test eye.

[0033] In a 27th aspect of some embodiments, in any of the 17th to 26th aspects, the interference optical system includes a polarization state changing member that is arranged in the optical path of the measurement light or the optical path of the reference light and changes the polarization state of the measurement light or the polarization state of the reference light, and includes a seventh control step of controlling the optical scanner to deflect the measurement light in a direction intersecting the optical axis of the interference optical system, and an eighth control step of controlling the polarization state changing member based on the detection result of the interference light obtained by the interference optical system by irradiating the measurement light deflected in the seventh control step onto the test eye.

[0034] In the 28th aspect of some embodiments, in any one of the 17th to 27th aspects, the astigmatism correction optical member can change the cylindrical power and the cylindrical axis angle.

[0035] In the 29th aspect of some embodiments, in the 28th aspect, the astigmatism correction optical member includes a variable cross-cylinder lens.

[0036] In the 30th aspect of some embodiments, in the 28th or 29th aspect, it includes a third display control step of causing at least one of the cylindrical power and the cylindrical axis angle to be displayed on a display means.

[0037] In the 31st aspect of some embodiments, in any one of the 17th to 30th aspects, the first control step deflects the measurement light in the horizontal direction and the vertical direction by controlling the light scanner so as to deflect the measurement light in a circular shape.

[0038] In the 32nd aspect of some embodiments, in the 31st aspect, when the diffraction limit is r, the diameter of the circular scan line in the eye to be examined is R, and the number of A-lines in the scan line is N, R×π / N < r is satisfied.

[0039] The 33rd aspect of some embodiments is a program for causing a computer to execute each step of the control method of the ophthalmic device according to any one of the 17th to 32nd aspects.

[0040] Note that the configurations according to the above-described plurality of aspects can be arbitrarily combined.

Advantages of the Invention

[0041] According to the embodiments of the present invention, even when the light source is speeded up, a new technique for adjusting the imaging conditions with high precision can be provided.

Brief Description of the Drawings

[0042] [Figure 1] 1 is a schematic diagram illustrating an example of the configuration of an optical system of an ophthalmologic apparatus according to an embodiment. [Figure 2] 1 is a schematic diagram illustrating an example of the configuration of an optical system of an ophthalmologic apparatus according to an embodiment. [Figure 3] 1 is a schematic diagram illustrating an example of the configuration of an optical system of an ophthalmologic apparatus according to an embodiment. [Figure 4] FIG. 2 is a schematic diagram illustrating an example of the configuration of a processing system of an ophthalmologic apparatus according to an embodiment. [Figure 5] FIG. 2 is a schematic diagram illustrating an example of the configuration of a processing system of an ophthalmologic apparatus according to an embodiment. [Figure 6] 3A to 3C are diagrams illustrating the operation of the ophthalmologic apparatus according to the embodiment. [Figure 7A] 3A to 3C are diagrams illustrating the operation of the ophthalmologic apparatus according to the embodiment. [Figure 7B] 3A to 3C are diagrams illustrating the operation of the ophthalmologic apparatus according to the embodiment. [Figure 8A] 3A to 3C are diagrams illustrating the operation of the ophthalmologic apparatus according to the embodiment. [Figure 8B] 3A to 3C are diagrams illustrating the operation of the ophthalmologic apparatus according to the embodiment. [Figure 9] FIG. 4 is a flowchart of an example of the operation of the ophthalmologic apparatus according to the embodiment. [Figure 10A] FIG. 4 is a flowchart of an example of the operation of the ophthalmologic apparatus according to the embodiment. [Figure 10B] FIG. 4 is a flowchart of an example of the operation of the ophthalmologic apparatus according to the embodiment. [Figure 11] 3A to 3C are diagrams illustrating the operation of the ophthalmologic apparatus according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0043] An ophthalmic apparatus, a control method for an ophthalmic apparatus, and a program according to the present invention will be described in detail with reference to the accompanying drawings. Note that the contents of documents cited in this specification and any publicly known techniques may be incorporated into the following embodiments.

[0044] The ophthalmologic apparatus according to the embodiment includes an interference optical system, scans the subject's eye with deflected measurement light using an optical scanner, and adjusts the imaging conditions (measurement conditions) based on the detection results of the obtained interference light. The interference optical system splits light from a light source into measurement light and reference light, irradiates the subject's eye with the measurement light via the optical scanner, and detects interference light between the reference light and return light of the measurement light from the subject's eye. The optical scanner deflects the measurement light according to a predetermined scan pattern (deflection pattern). The adjustment of imaging conditions includes adjustment of the position of the imaging region, focus adjustment, polarization adjustment, and astigmatism correction.

[0045] In some embodiments, the interference optical system includes an astigmatism correction optical element (astigmatism correction element). The optical scanner deflects the measurement light in horizontal and vertical directions in a plane perpendicular to the optical axis of the interference optical system. The optical scanner according to some embodiments deflects the measurement light in meridional and sagittal directions. The meridional direction is a concentric direction centered on the optical axis of the interference optical system. The sagittal direction is a radial direction centered on the optical axis of the interference optical system. The ophthalmic apparatus corrects astigmatism based on the detection result of the interference light obtained by scanning the test eye with the measurement light deflected by the optical scanner.

[0046] Examples of astigmatism correction optical members include a variable cross cylinder (hereinafter referred to as VCC) lens, a liquid crystal lens, a deformable mirror, and an Alvarez lens.

[0047] This allows the horizontal and vertical information to be acquired with fewer scans than in the case of raster scanning (two or more line scans). Therefore, the horizontal and vertical information can be acquired in a shorter time than the time required for raster scanning, and astigmatism can be corrected from the acquired horizontal and vertical information. Here, the time required for raster scanning corresponds to, for example, the sum of the time required for multiple line scans and the time required for flyback between each line scan. In other words, according to the embodiment, even when the light source is fast, astigmatism can be corrected with high precision without being affected by eye movement, etc.

[0048] In particular, by adopting circle scanning as the scanning mode for deflecting the measurement light in the horizontal and vertical directions in a plane perpendicular to the optical axis of the interference optical system, the scanning speed can be made nearly constant across the entire scanning area. This makes it possible to obtain uniform scanning results across the entire scanning area, enabling high-precision correction of astigmatism based on the uniform scanning results. In addition, because the influence of specular reflection from the vertex of the objective lens is reduced, high-precision correction of astigmatism based on artifact-free scanning results becomes possible.

[0049] In some embodiments, the interference optical system includes a focus-position changing member that can change the focal position of the measurement light. The ophthalmic apparatus scans the test eye with deflected measurement light using an optical scanner and controls the focus-position changing member based on a detection result of the obtained interference light. The deflection pattern of the measurement light may be any pattern. For example, the ophthalmic apparatus controls the focus-position changing member based on a detection result of the interference light obtained by scanning the test eye with measurement light deflected in a line direction intersecting the optical axis of the interference optical system or with measurement light deflected in horizontal and vertical directions in a plane perpendicular to the optical axis of the interference optical system.

[0050] The focusing position changing member may be a lens that can move along the optical axis, a liquid crystal lens, an Alvarez lens, or the like.

[0051] In some embodiments, the interference optical system includes an optical path length changing member that changes the optical path length difference between the measurement light and the reference light. The ophthalmic apparatus scans the test eye with deflected measurement light using an optical scanner and controls the optical path length changing member based on the detection result of the obtained interference light. The deflection pattern of the measurement light may be any pattern. For example, the ophthalmic apparatus controls the optical path length changing member based on the detection result of the interference light obtained by scanning the test eye with measurement light deflected in a line direction intersecting the optical axis of the interference optical system or measurement light deflected in horizontal and vertical directions in a plane perpendicular to the optical axis of the interference optical system.

[0052] In some embodiments, the interference optical system includes a polarization state changing member that changes the polarization state of the measurement light or the polarization state of the reference light. The ophthalmic apparatus scans the test eye with the deflected measurement light using an optical scanner and controls the polarization state changing member based on the detection result of the obtained interference light. The deflection pattern of the measurement light may be any pattern. For example, the ophthalmic apparatus controls the polarization state changing member based on the detection result of the interference light obtained by scanning the test eye with the measurement light deflected in a line direction intersecting the optical axis of the interference optical system or the measurement light deflected in horizontal and vertical directions in a plane perpendicular to the optical axis of the interference optical system.

[0053] The control method for an ophthalmic apparatus according to the embodiment is a method for controlling the ophthalmic apparatus according to the embodiment. The program according to the embodiment causes a computer to execute each step of the control method for an ophthalmic apparatus according to the embodiment. The recording medium according to the embodiment records the program according to the embodiment.

[0054] In the following embodiments, a circle scan is used as an example of a scan mode for deflecting the measurement light in the horizontal and vertical directions in a plane perpendicular to the optical axis of the interference optical system. However, the embodiments can also be applied to cases where the measurement light is deflected using a scan pattern other than the circle scan.

[0055] The ophthalmologic apparatus according to the embodiment can perform OCT on any part of the subject's eye, such as the fundus or the anterior segment. In this specification, images acquired by OCT may be collectively referred to as OCT images. Furthermore, the measurement operation for forming an OCT image may be referred to as OCT measurement.

[0056] In the following embodiments, a case where a swept-source OCT technique is used in measurement or imaging using OCT will be described in detail. However, the configuration according to the embodiment can also be applied to an ophthalmic apparatus that uses other types of OCT (for example, spectral domain type or time domain type).

[0057] [composition] As shown in FIGS. 1 to 3, the ophthalmologic apparatus 1 includes a fundus camera unit 2, an OCT unit 100, and an arithmetic and control unit 200. The fundus camera unit 2 has an optical system similar to that of a conventional fundus camera. The OCT unit 100 is provided with an optical system for acquiring an OCT image of the fundus (or anterior segment). The arithmetic and control unit 200 includes a computer that executes various arithmetic processes, control processes, etc.

[0058] [Fundus camera unit 2] The fundus camera unit 2 shown in FIG. 1 is provided with an optical system for acquiring a two-dimensional image (fundus image) representing the surface morphology of the fundus Ef of the subject's eye E. The fundus image includes an observed image, a photographed image, and the like. The observed image is, for example, a monochrome moving image formed at a predetermined frame rate using near-infrared light. The photographed image may be, for example, a color image obtained by flashing visible light, or a monochrome still image using near-infrared light or visible light as illumination light. The fundus camera unit 2 may be configured to acquire images other than these, such as a fluorescein fluorescent image, an indocyanine green fluorescent image, or an autofluorescent image.

[0059] The fundus camera unit 2 is provided with a chin rest and a forehead rest for supporting the face of the subject. The fundus camera unit 2 is further provided with an illumination optical system 10 and a photographing optical system 30. The illumination optical system 10 irradiates the fundus Ef with illumination light. The photographing optical system 30 guides the fundus reflection light of this illumination light to an imaging device (CCD image sensors (sometimes simply referred to as CCDs) 35, 38). The photographing optical system 30 also guides measurement light from the OCT unit 100 to the fundus Ef, and also guides measurement light that has passed through the fundus Ef to the OCT unit 100.

[0060] 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 reflecting mirror 12 having a curved reflecting surface, passes through a condenser lens 13, and passes through a visible light cut filter 14 to become near-infrared light. The observation illumination light is then focused near the imaging light source 15, reflected by a mirror 16, and passes through relay lenses 17 and 18, an aperture 19, and a relay lens 20. The observation illumination light is then reflected by the peripheral portion (the area surrounding the hole) of the apertured mirror 21, passes through a dichroic mirror 48, and is refracted by the objective lens 22 to illuminate the fundus Ef. Note that an LED (Light Emitting Diode) can also be used as the observation light source.

[0061] The fundus reflected light of the observation illumination light is refracted by the objective lens 22, transmitted through the dichroic mirror 48, passes through the hole formed in the central region of the aperture mirror 21, transmitted through the dichroic mirror 55, passes through the focusing lens 31, and is reflected by the mirror 32. This fundus reflected light then transmits through the half mirror 33A, is reflected by the dichroic mirror 33, and is focused by the condenser lens 34 onto the light receiving surface of the CCD image sensor 35. The CCD image sensor 35 detects the fundus reflected light at, for example, a predetermined frame rate. An image (observation image) based on the fundus reflected light detected by the CCD image sensor 35 is displayed on the display device 3. When the focus of the photographing optical system 30 is adjusted to the anterior segment, an observation image of the anterior segment of the subject's eye E is displayed.

[0062] The imaging light source 15 includes, for example, a xenon lamp. Light (imaging illumination light) output from the imaging light source 15 is irradiated onto the fundus Ef along the same path as the observation illumination light. Fundus reflection light of the imaging illumination light is guided to the dichroic mirror 33 along the same path as the observation illumination light, passes through the dichroic mirror 33, is reflected by a mirror 36, and is focused on the light receiving surface of a CCD image sensor 38 by a condenser lens 37. An image (photographed image) based on the fundus reflection light detected by the CCD image sensor 38 is displayed on the display device 3. The display device 3 that displays the observation image and the display device 3 that displays the photographed image may be the same or different. When similar photography is performed by illuminating the subject's eye E with infrared light, an infrared photographed image is displayed. An LED may also be used as the imaging light source.

[0063] The LCD (Liquid Crystal Display) 39 displays a fixation target and a visual target for visual acuity measurement. The fixation target is a visual target for causing the subject's eye E to fixate, and is used during fundus photography, OCT measurement, and the like.

[0064] A portion of the light output from the LCD 39 is reflected by the half mirror 33A, reflected by the mirror 32, passes through the focusing lens 31 and the dichroic mirror 55, and passes through the hole in the aperture mirror 21. The light that has passed through the hole is transmitted through the dichroic mirror 48, refracted by the objective lens 22, and projected onto the fundus Ef.

[0065] The fixation position of the subject's eye E can be changed by changing the display position of the fixation target on the screen of the LCD 39. As with conventional fundus cameras, the fixation position of the subject's eye E can be, for example, a position for acquiring an image centered on the macular region of the fundus Ef, a position for acquiring an image centered on the optic disc, or a position for acquiring an image centered on the center of the fundus between the macular region and the optic disc. It is also possible to arbitrarily change the display position of the fixation target.

[0066] Furthermore, the fundus camera unit 2 is provided with an alignment optical system 50 and a focus optical system 60, similar to conventional fundus cameras. The alignment optical system 50 generates a target (alignment target) for aligning the device optical system with the subject's eye E. The focus optical system 60 generates a target (split target) for focusing on the fundus Ef.

[0067] Light (alignment light) output from an LED 51 of the alignment optical system 50 passes through apertures 52, 53 and a relay lens 54, is reflected by a dichroic mirror 55, and passes through the hole in the aperture mirror 21. The light that has passed through the hole is transmitted through a dichroic mirror 48 and is projected onto the cornea of ​​the subject's eye E by the objective lens 22.

[0068] The corneal reflection light of the alignment light passes through the objective lens 22, dichroic mirror 48, and the hole, and a portion of it passes through the dichroic mirror 55, passes through the focusing lens 31, is reflected by the mirror 32, and passes through the half mirror 33A. The corneal reflection light that passes through the half mirror 33A is reflected by the dichroic mirror 33 and is projected onto the light-receiving surface of the CCD image sensor 35 by the condenser lens 34. The light-receiving image (alignment target) by the CCD image sensor 35 is displayed on the display device 3 together with the observation image. The user performs alignment by performing operations similar to those of a conventional fundus camera. Alternatively, alignment may be performed by the arithmetic and control unit 200 analyzing the position of the alignment target and moving the optical system (auto-alignment function).

[0069] When performing focus adjustment, the reflecting surface of a reflecting rod 67 is obliquely disposed on the optical path of the illumination optical system 10. Light (focusing light) output from an LED 61 of the focusing optical system 60 passes through a relay lens 62, is split into two light beams by a split target plate 63, passes through a two-hole diaphragm 64, and is reflected by a mirror 65. The light reflected by the mirror 65 is once imaged on the reflecting surface of the reflecting rod 67 by a condenser lens 66 and is then reflected. The focusing light further passes through a relay lens 20, is reflected by an apertured mirror 21, passes through a dichroic mirror 48, is refracted by an objective lens 22, and is projected onto the fundus Ef.

[0070] The fundus reflection light of the focusing light travels the same path as the cornea reflection light of the alignment light and is detected by the CCD image sensor 35. The light image (split target) received by the CCD image sensor 35 is displayed on the display device 3 together with the observation image. As in the conventional method, the arithmetic and control unit 200 analyzes the position of the split target and moves the focusing lens 31 and the focus optical system 60 to adjust the focus (autofocus function). Alternatively, manual focusing may be performed while viewing the split target.

[0071] The dichroic mirror 48 branches the optical path for OCT measurement from the optical path for fundus imaging. The dichroic mirror 48 reflects light in the wavelength band used for OCT measurement and transmits light for fundus imaging. The optical path for OCT measurement is provided with, in order 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 mirror 44, an OCT focusing lens 45, a field lens 46, and a variable cross cylinder (hereinafter, VCC) lens 47.

[0072] The optical path length changing unit 41 is configured to be movable in the direction of the arrow shown in Fig. 1 and changes the optical path length of the optical path for OCT measurement. This change in the optical path length is used to correct the optical path length according to the axial length of the subject's eye E, adjust the interference state, etc. The optical path length changing unit 41 is configured to include, for example, a corner cube and a mechanism for moving it.

[0073] The optical scanner 42 is disposed at a position optically conjugate with the pupil of the subject's eye (pupil conjugate position) or in the vicinity thereof. The optical scanner 42 changes the traveling direction of light (measurement light) passing through the optical path for OCT measurement. The optical scanner 42 is controlled by the arithmetic and control unit 200 (described later) and can deflect the measurement light one-dimensionally or two-dimensionally.

[0074] The optical scanner 42 includes, for example, a first galvanometer mirror, a second galvanometer mirror, and a mechanism for independently driving them. The first galvanometer mirror deflects the measurement light LS so as to scan the imaging site (fundus oculi Ef or anterior segment) in a horizontal direction (x direction) perpendicular to the optical axis of the OCT optical system 8. The x direction is the horizontal direction in a plane perpendicular to the optical axis of the interference optical system. The second galvanometer mirror deflects the measurement light LS deflected by the first galvanometer mirror so as to scan the imaging site in a vertical direction (y direction) perpendicular to the optical axis of the OCT optical system 8. The y direction is the vertical direction in a plane perpendicular to the optical axis of the interference optical system. This allows the imaging site to be scanned with the measurement light LS in any direction on the xy plane.

[0075] For example, it is possible to move the irradiation position of the measurement light along any trajectory on the xy plane by simultaneously controlling the orientations of the first galvanometer mirror and the second galvanometer mirror included in the optical scanner 42. This makes it possible to scan the imaging region according to a desired scan pattern.

[0076] The OCT focusing lens 45 is movable along the optical path (optical axis of the interference optical system) of the measurement light LS. The OCT focusing lens 45 is controlled by an arithmetic and control unit 200 (described later) and moves along the optical path of the measurement light LS.

[0077] In some embodiments, a liquid crystal lens or an Alvarez lens is provided instead of the OCT focusing lens 45. The liquid crystal lens or the Alvarez lens is controlled by the arithmetic and control unit 200, similar to the OCT focusing lens 45.

[0078] The VCC lens 47 is disposed in the optical path of the measurement light and changes at least one of the cylindrical power (cylindrical power) and the cylindrical axis angle (cylindrical axis angle). The VCC lens 47 has two cylindrical lenses (optical elements) disposed opposite each other and is configured to change at least one of the cylindrical power and the cylindrical axis angle by changing at least one of the axial directions of the two cylindrical lenses. In this embodiment, each of the two cylindrical lenses is configured to be independently rotatable so that the two axial directions are changed relative to each other. Furthermore, the two cylindrical lenses are configured to be rotatable together while maintaining the angle formed by the two axial directions.

[0079] The VCC lens 47 is placed at a position optically conjugate with the pupil of the subject's eye (pupil conjugate position) or in the vicinity thereof. In the embodiment, since the optical scanner 42 is placed at a position optically conjugate with the pupil of the subject's eye, the VCC lens 47 is placed in the vicinity of the position optically conjugate with the pupil of the subject's eye.

[0080] When the purpose is to correct the astigmatic power of the subject's eye E, even if the VCC lens 47 is placed near the pupil conjugate position, it can be considered that the deviation of the placement position of the VCC lens 47 from the pupil conjugate position has little effect on the cylindrical power and cylindrical axis angle changed by the VCC lens 47.

[0081] When the VCC lens 47 is controlled based on optometry data (objective measurement values ​​or subjective test values) of the subject's eye E, the optometry data is mainly measurement values ​​at the fovea of ​​the subject's eye E. However, it can be considered that deviation of the placement position of the VCC lens 47 from the pupil conjugate position has little effect on the cylindrical power and cylindrical axis angle changed by the VCC lens 47. Therefore, even if the imaging site is a site different from the fovea, the VCC lens 47 may be placed near the pupil conjugate position.

[0082] As shown in FIG. 3, the VCC lens 47 includes cylindrical lenses 471 and 472 (focal lengths f0 and -f0) having the same power but different signs. The cylindrical lens 471 (VCC1) has a convex surface (positive power) and is provided rotatable in a rotation direction dr1 around the optical path of the measurement light LS (the optical axis SO of the interference optical system). The cylindrical lens 472 (VCC2) has a concave surface (negative power) and is provided rotatable in a rotation direction dr2 around the optical axis SO. The cylindrical lenses 471 and 472 are driven by a driving device such as a pulse motor and are rotated independently around the optical axis SO. When the cylindrical lenses 471 and 472 are rotated in opposite directions, the cylindrical power changes. When the cylindrical lenses 471 and 472 are rotated together in the same direction, the cylindrical axis angle changes.

[0083] For example, any cylindrical power can be generated by rotating the cylindrical lenses 471 and 472 in opposite directions from a state in which the cylindrical axes of the cylindrical lenses 471 and 472 are tilted at a predetermined angle (for example, 45 degrees) with respect to the optical axis SO. Also, any cylindrical axis angle can be generated by rotating the cylindrical lenses 471 and 472 integrally in the same direction.

[0084] [OCT Unit 100] An example of the configuration of the OCT unit 100 will be described with reference to FIG. 2. The OCT unit 100 is provided with an optical system for acquiring an OCT image of the fundus Ef. This optical system has the same configuration as a conventional swept-source type OCT device. That is, this optical system is an interference optical system that splits light from a wavelength scanning (wavelength swept) light source into measurement light and reference light, causes the measurement light that has passed through the fundus Ef to interfere with the reference light that has passed through a reference light path to generate interference light, and detects this interference light. The detection result (detection signal) of the interference light in the interference optical system is a signal indicating the spectrum of the interference light, and is sent to the arithmetic and control unit 200.

[0085] The light source unit 101 includes a wavelength scanning (wavelength sweeping) light source that can scan (sweep) the wavelength of emitted light, similar to a general swept-source type OCT device. The light source unit 101 changes the output wavelength over time in the near-infrared wavelength band that is invisible to the human eye.

[0086] Light L0 output from light source unit 101 is guided by optical fiber 102 to polarization controller 103, where its polarization state is adjusted. The polarization controller 103 adjusts the polarization state of light L0 guided through optical fiber 102, for example, by applying external stress to looped optical fiber 102.

[0087] The light L0, whose polarization state has been adjusted by the polarization controller 103, is guided by an optical fiber 104 to a fiber coupler 105, where it is split into a measurement light LS and a reference light LR.

[0088] The reference light LR is guided by an optical fiber 110 to a collimator 111 and converted into a parallel beam. The parallel beam of reference light LR passes through an optical path length correction member 112 and a dispersion compensation member 113 and is guided to a corner cube 114. The optical path length correction member 112 acts as a delay means for matching the optical path lengths (optical distances) of the reference light LR and the measurement light LS. The dispersion compensation member 113 acts as a dispersion compensation means for matching the dispersion characteristics of the reference light LR and the measurement light LS.

[0089] The corner cube 114 reverses the traveling direction of the reference light LR, which has been converted into a parallel beam by the collimator 111. The optical path of the reference light LR incident on the corner cube 114 is parallel to the optical path of the reference light LR emerging from the corner cube 114. The corner cube 114 is movable in directions along the incident and emerging optical paths of the reference light LR. This movement changes the length of the optical path (reference optical path) of the reference light LR.

[0090] The reference light LR that has passed through the corner cube 114 passes through a dispersion compensation member 113 and an optical path length correction member 112, is converted from a parallel beam into a convergent beam by a collimator 116, and enters an optical fiber 117. The reference light LR that has entered the optical fiber 117 is guided to a polarization controller 118, where the polarization state of the reference light LR is adjusted.

[0091] The polarization controller 118 has, for example, the same configuration as the polarization controller 103. The reference light LR whose polarization state has been adjusted by the polarization controller 118 is guided to an attenuator 120 by an optical fiber 119, and the light intensity is adjusted under the control of the arithmetic and control unit 200. The reference light LR whose light intensity has been adjusted by the attenuator 120 is guided to a fiber coupler 122 by an optical fiber 121.

[0092] The measurement light LS generated by the fiber coupler 105 is guided by the optical fiber 127 and collimated by the collimating lens unit 40. The collimated measurement light LS passes through the optical path length changing unit 41, the VCC lens 47, the optical scanner 42, the collimating lens 43, the mirror 44, the OCT focusing lens 45, the field lens 46, and the VCC lens 47 to reach the dichroic mirror 48. The measurement light LS is then reflected by the dichroic mirror 48, refracted by the objective lens 22, and irradiated onto the fundus Ef. The measurement light LS is scattered (including reflected) at various depth positions in the fundus Ef. The backscattered light of the measurement light LS by the fundus Ef travels in the opposite direction along the same path as the outward path and is guided to the fiber coupler 105, and reaches the fiber coupler 122 via the optical fiber 128.

[0093] Fiber coupler 122 generates interference light by combining (causing interference between) measurement light LS incident via optical fiber 128 and reference light LR incident via optical fiber 121. Fiber coupler 122 splits the interference light between measurement light LS and reference light LR at a predetermined splitting ratio (for example, 1:1) to generate a pair of interference light LC. The pair of interference light LC emitted from fiber coupler 122 is guided to detector 125 by optical fibers 123 and 124, respectively.

[0094] The detector 125 is, for example, a balanced photodiode having a pair of photodetectors that respectively detect a pair of interference light LC and outputting the difference between the detection results. The detector 125 sends the detection results (detection signals) to the arithmetic and control unit 200. The arithmetic and control unit 200 forms a tomographic image by performing a Fourier transform or the like on the spectral distribution based on the detection results obtained by the detector 125, for example, for each series of wavelength scans (each A-line). The arithmetic and control unit 200 displays the formed image on the display device 3.

[0095] Although the embodiment employs a Michelson-type interferometer, any type of interferometer, such as a Mach-Zehnder-type, may be appropriately employed. In the embodiment, the interference optical system may include the collimating lens unit 40, the optical path length changing unit 41, the optical scanner 42, the collimating lens 43, the mirror 44, the OCT focusing lens 45, the field lens 46, and the VCC lens 47 shown in FIG. 1 in addition to the configuration shown in FIG. 2 . This interference optical system is an example of an “interference optical system” according to this embodiment. The VCC lens 47 (and the VCC driver 47A) is an example of an “astigmatism correction optical member” according to the embodiment. The OCT focusing lens 45 (and the OCT focusing driver 45A) is an example of a “focusing position changing member” according to the embodiment. At least one of the optical path length changing unit 41 and the corner cube 114 (and the reference driver 114A) is an example of an “optical path length changing member” according to the embodiment. At least one of the polarization controllers 103 and 118 is an example of a “polarization state changing member” according to the embodiment. The display control unit 211C is an example of a "first display control unit," a "second display control unit," or a "third display control unit" according to the embodiment.

[0096] [Arithmetic and control unit 200] The configuration of the arithmetic and control unit 200 will be described.

[0097] 4 and 5 show block diagrams of a configuration example of a processing system of the ophthalmologic apparatus 1 according to the embodiment. Fig. 5 is a functional block diagram of a configuration example of the analysis unit 231 in Fig. 4. In Fig. 4, the same parts as those in Fig. 1 or 2 are denoted by the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0098] The arithmetic and control unit 200 forms an OCT image of the fundus oculi Ef by analyzing the detection signal input from the detector 125. The arithmetic and control process for this purpose is the same as that of a conventional swept source type OCT device.

[0099] 4, the arithmetic and control unit 200 includes a control unit 210, and controls each part of the fundus camera unit 2, the display device 3, and the OCT unit 100. For example, the arithmetic and control unit 200 forms an OCT image (tomographic image, three-dimensional image) of the fundus Ef, and causes the formed OCT image to be displayed on the display device 3.

[0100] The control of the fundus camera unit 2 includes operation control of the observation light source 11, the imaging light source 15 and the LEDs 51 and 61, operation control of the LCD 39, movement control of the focusing lens 31, movement control of the OCT focusing lens 45, movement control of the reflecting rod 67, movement control of the focus optical system 60, movement control of the optical path length changing unit 41, drive control of the VCC lens 47, operation control of the optical scanner 42, etc.

[0101] The control of the OCT unit 100 includes operation control of the light source unit 101 , movement control of the corner cube 114 , operation control of the detector 125 , operation control of the attenuator 120 , operation control of the polarization controllers 103 and 118 , and the like.

[0102] The arithmetic and control unit 200 includes, for example, a processor, a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk drive, a communication interface, and the like, similar to a conventional computer. A computer program for controlling the ophthalmologic apparatus 1 is stored in a storage device such as a hard disk drive. The arithmetic and control unit 200 may include various circuit boards, for example, a circuit board for forming an OCT image. The arithmetic and control unit 200 may also include operation devices (input devices) such as a keyboard and a mouse, and a display device such as an LCD.

[0103] The processor includes circuits such as a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), or a field programmable gate array (FPGA)). The processor implements the functions of the embodiments by, for example, reading and executing a program stored in a memory circuit or a storage device. The memory circuit or storage device may be included in the processor. Alternatively, the memory circuit or storage device may be provided external to the processor. In some embodiments, the functions of the arithmetic and control unit 200 are implemented by one or more processors.

[0104] The fundus camera unit 2, the display device 3, the OCT unit 100 and the arithmetic and control unit 200 may be configured integrally (i.e., within a single housing) or may be configured separately in two or more housings.

[0105] The control unit 210 includes a main control unit 211 and a storage unit 212 .

[0106] (Main control unit 211) The main controller 211 performs various controls by outputting control signals to each component of the above-described ophthalmologic apparatus 1. In particular, the main controller 211 controls the CCD image sensors 35, 38, LCD 39, focus driver 31A, optical path length changer 41, optical scanner 42, OCT focus driver 45A, and VCC driver 47A for the fundus camera unit 2. Furthermore, the main controller 211 controls the light source unit 101, reference driver 114A, polarization controllers 103, 118, attenuator 120, and detector 125 for the OCT unit 100.

[0107] The main control unit 211 controls the exposure time (charge accumulation time), sensitivity, frame rate, etc. of the CCD image sensor 35 or the CCD image sensor 38. In some embodiments, the main control unit 211 controls the CCD image sensor 35 or the CCD image sensor 38 so as to acquire an image of desired image quality.

[0108] The main control unit 211 controls the display of fixation targets and visual targets for visual acuity measurement on the LCD 39. This allows the visual targets presented to the subject's eye E to be switched or the type of visual target to be changed. In addition, by changing the display position of the visual target on the LCD 39, it is possible to change the visual target presentation position relative to the subject's eye E.

[0109] The focusing driver 31A moves the focusing lens 31 in the optical axis direction. The main controller 211 controls the focusing driver 31A so that the focusing lens 31 is positioned at a desired focusing position. This changes the focusing position of the photographing optical system 30.

[0110] For example, the main control unit 211 analyzes the position of the split target in the received light image (split target) obtained by the CCD image sensor 35, and controls the focusing drive unit 31A and the focus optical system 60. Alternatively, for example, the main control unit 211 controls the focusing drive unit 31A and the focus optical system 60 in response to an operation performed by a user on an operation unit 240B (described later) while displaying a live image of the subject's eye E on a display unit 240A (described later).

[0111] The main controller 211 changes the optical path length of the measurement light LS by controlling the optical path length changer 41. This changes the difference between the optical path length of the measurement light LS and the optical path length of the reference light LR.

[0112] For example, the main control unit 211 analyzes the detection results of the interference light LC obtained by OCT measurement (or an OCT image formed based on the detection results), and controls the optical path length changing unit 41 so that the measurement site is at the desired depth position.

[0113] The main control unit 211 (an optical scanner control unit 211A described later) controls the optical scanner 42. The main control unit 211 controls the optical scanner 42 so as to deflect the measurement light LS according to a deflection pattern corresponding to a preset scan mode.

[0114] Examples of such scanning modes include line scan, cross scan, circle scan, radial scan, concentric circle scan, multi-line cross scan, spiral scan, Lissajous scan, and 3D scan.

[0115] Line scan is a scan mode in which the measurement light LS is deflected so that the movement locus of the irradiation position of the measurement light LS at the imaging region (measurement region) is linear. The line direction of the movement locus can be changed (rotated) around the optical axis on the xy plane.

[0116] For example, line scanning includes horizontal scanning and vertical scanning. Horizontal scanning is a scanning mode in which the measurement light LS is deflected so that the movement trajectory of the irradiation position of the measurement light LS is in the horizontal direction (x direction). Horizontal scanning also includes a mode in which the measurement light LS is scanned along multiple horizontally extending scan lines arranged in the vertical direction (y direction). In this mode, the spacing between the scan lines can be set arbitrarily. Furthermore, by sufficiently narrowing the spacing between adjacent scan lines, a three-dimensional image can be formed (three-dimensional scanning). The same applies to vertical scanning.

[0117] The cross scan is a scan mode in which the measurement light LS is deflected so that the movement locus of the irradiation position of the measurement light LS at the imaging region (measurement region) is cross-shaped. For example, the cross scan can be performed by executing two line scans whose line directions intersect with each other. The angle at which the two line scans intersect can be changed. In some embodiments, the scan lengths in the B-scan direction of the two line scans are the same. In some embodiments, the scan lengths in the B-scan direction of the two line scans are different.

[0118] Circle scanning is a scanning mode in which the measurement light LS is deflected so that the movement locus of the irradiation position of the measurement light LS in the imaging region (measurement region) is, for example, circular around the optical axis SO. For example, in circle scanning, the measurement light LS is deflected so that the movement locus is a perfect circle, an ellipse, or an arc (part of a circumference).

[0119] Radial scanning is a scanning mode in which the measurement light LS is deflected so that the movement locus of the irradiation position of the measurement light LS at the imaging region (measurement region) is radial, for example, from the optical axis SO. In radial scanning, the irradiation position of the measurement light LS is moved along a radial locus consisting of multiple straight loci arranged at a predetermined angle. The above-mentioned cross scanning is one form of radial scanning.

[0120] For example, in a radial scan, two or more line scans are performed with different B-scan directions. In some embodiments, the scan lengths in the B-scan direction of the two or more line scans are the same. In some embodiments, the scan length in the B-scan direction of at least one of the two or more line scans is different from the scan lengths of the other line scans.

[0121] Concentric scanning is a scanning mode in which the measurement light LS is deflected so that the movement locus of the irradiation position of the measurement light LS in the imaging region (measurement region) is, for example, concentric around the optical axis SO. For example, in concentric scanning, the measurement light LS is deflected so that the movement locus of each circle is a perfect circle, an ellipse, or an arc (part of a circumference). In some embodiments, concentric scanning is performed by combining multiple circle scans with different diameters. Circle scanning is one aspect of concentric scanning.

[0122] A multi-line cross scan is a scan pattern in which a group of parallel horizontal scan lines (e.g., five lines) and a group of parallel vertical scan lines (e.g., five lines) are arranged so that they intersect at right angles near the center of both scan line groups.

[0123] For example, in each scan line group in the multi-line cross scan, two or more line scans are performed. In some embodiments, the scan lengths in the B-scan direction of the two or more line scans are the same. In some embodiments, the scan length in the B-scan direction of at least one of the two or more line scans is different from the scan lengths of the other line scans.

[0124] Spiral scanning is a scanning mode in which the measurement light LS is deflected so that the movement locus of the irradiation position of the measurement light LS at the imaging region (measurement region) is, for example, spiral around the optical axis SO. In spiral scanning, the irradiation position of the measurement light LS is moved along a spiral locus while gradually decreasing (or increasing) the radius of rotation.

[0125] Lissajous scanning is a scanning mode in which the measuring light LS is deflected so that the movement locus of the irradiation position of the measuring light LS at the imaging region (measurement region) follows a Lissajous curve. Lissajous scanning is disclosed in, for example, Japanese Patent Application Laid-Open No. 2018-68578.

[0126] Among the above scan modes, examples of scan modes that deflect the measurement light LS in the horizontal and vertical directions in a plane perpendicular to the optical axis of the interference optical system include circle scan, radial scan, concentric circle scan, multi-line cross scan, spiral scan, Lissajous scan, and three-dimensional scan.

[0127] By scanning the imaging area with the measurement light LS according to the deflection pattern corresponding to the scan mode described above, a tomographic image can be obtained in a plane defined by the direction along the scan line (scan trajectory) and the fundus depth direction (z direction).

[0128] The area of ​​the subject's eye E that is the target of scanning with the measurement light LS as described above, that is, the area of ​​the subject's eye E that is the target of OCT imaging, is called the scan area. For example, the scan area in a three-dimensional scan is a rectangular area in which multiple horizontal scans are arranged. For example, the scan area in a concentric scan is a disk-shaped area surrounded by the locus of the circular scan with the largest diameter. Furthermore, the scan area in a radial scan is a disk-shaped (or polygonal) area connecting both end positions of each scan line.

[0129] The OCT focusing driver 45A moves the OCT focusing lens 45 along the optical axis SO of the measurement light LS. The main controller 211 controls the OCT focusing driver 45A so that the OCT focusing lens 45 is positioned at a desired focusing position. This changes the focusing position of the measurement light LS. The focusing position of the measurement light LS corresponds to the depth position (z position) of the beam waist of the measurement light LS.

[0130] For example, the main control unit 211 controls the OCT focusing drive unit 45A based on the signal-to-noise ratio of the detection result of the interference light LC obtained by OCT measurement, or an evaluation value (including a statistical value of the evaluation value) corresponding to the image quality of the OCT image formed based on the detection result.

[0131] When a liquid crystal lens or an Alvarez lens is provided instead of the OCT focusing lens 45, the main control unit 211 can control the liquid crystal lens or the Alvarez lens in the same way as it controls the OCT focusing driver 45A.

[0132] The VCC driver 47A rotates the cylindrical lenses 471 and 472 independently of each other about the optical axis SO of the measurement light LS, thereby changing at least one of the cylindrical power and the cylindrical axis angle.

[0133] For example, the main controller 211 controls the VCC driver 47A based on the signal-to-noise ratio of the detection result of the interference light LC obtained by OCT measurement, or an evaluation value (including a statistical value of the evaluation value) corresponding to the image quality of the OCT image formed based on the detection result. Specifically, the main controller 211 controls the VCC driver 47A based on the signal-to-noise ratio of the detection result of the interference light LC obtained by deflecting the measurement light LS according to a deflection pattern corresponding to a circle scan, or an evaluation value (including a statistical value of the evaluation value) corresponding to the image quality of the OCT image formed based on the detection result.

[0134] When a liquid crystal lens, a deformable mirror, or an Alvarez lens is provided instead of the VCC lens 47, the main control unit 211 can control the liquid crystal lens, the deformable mirror, or the Alvarez lens in the same way as the VCC driving unit 47A.

[0135] The main control unit 211 controls the light source unit 101. 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, changing the sweep wavelength range, and the like.

[0136] The reference driver 114A moves the corner cube 114 provided in the optical path of the reference light along this optical path, thereby changing the difference between the optical path length of the measurement light LS and the optical path length of the reference light LR.

[0137] For example, the main controller 211 analyzes the detection result of the interference light LC obtained by the OCT measurement (or an OCT image formed based on the detection result), and controls the reference driver 114A so that the measurement site is at a desired depth position. In some embodiments, only one of the optical path length changer 41 and the reference driver 114A is provided.

[0138] 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 interference light LC obtained by OCT measurement, or an evaluation value (including a statistical value of the evaluation value) corresponding to the image quality of the OCT image formed based on the detection result.

[0139] The main controller 211 controls the attenuator 120. For example, the main controller 211 controls the attenuator 120 based on the signal-to-noise ratio of the detection result of the interference light LC obtained by OCT measurement, or an evaluation value (including a statistical value of the evaluation value) corresponding to the image quality of the OCT image formed based on the detection result.

[0140] The main control unit 211 controls the detector 125. The control of the detector 125 includes control of the exposure time (charge accumulation time), sensitivity, frame rate, and the like.

[0141] The moving mechanism 150 moves the fundus camera unit 2 (OCT unit 100) three-dimensionally relative to the subject's eye E. For example, the main controller 211 can control the moving mechanism 150 to move the optical system provided in the fundus camera unit 2 three-dimensionally. This control is used for alignment and tracking. Tracking is the movement of the device optical system in accordance with the movement of the subject's eye E. When tracking is performed, alignment and focusing are performed in advance. Tracking is a function that maintains an appropriate positional relationship where alignment and focus are achieved by moving the device optical system in real time in accordance with the position and orientation of the subject's eye E based on images obtained by capturing a video of the subject's eye E.

[0142] In some embodiments, the main controller 211 (an optical scanner controller 211A described later) corrects the position of the scan range (second scan range) for OCT imaging in real time based on tracking information obtained by tracking control (tracking information obtained by tracking the optical system (interference optical system) with respect to the movement of the subject's eye E). The main controller 211 can control the optical scanner 42 to scan the corrected scan range with the measurement light LS.

[0143] Furthermore, the main control unit 211 (a display control unit 211C described later) causes the display device 3 (or a display unit 240A described later) to display various information. The information displayed on the display device 3 includes the imaging results (observation image, OCT image (an image of the subject's eye formed based on the detection result of the interference light LC obtained by scanning the second scan range with the measurement light LS), measurement results (measurement values), information indicating the result of changing the imaging conditions described later, and the like.

[0144] In the embodiment, a provisional imaging (provisional measurement) is performed before the actual imaging (actual measurement). The imaging conditions for the actual imaging are adjusted based on the detection result of the interference light LC acquired in the provisional imaging or the OCT image formed from the detection result.

[0145] As shown in FIG. 4, the main control unit 211 includes an optical scanner control unit 211A, a correction control unit 211B, and a display control unit 211C.

[0146] As described above, the optical scanner control unit 211A controls the optical scanner 42 to deflect the measurement light LS according to a deflection pattern corresponding to a preset scan mode. The optical scanner control unit 211A can control the optical scanner 42 in the provisional imaging according to a scan mode different from the scan mode executed in the actual imaging. For example, the optical scanner control unit 211A can control the optical scanner 42 in the provisional imaging to deflect the measurement light LS in a deflection direction different from the deflection direction of the measurement light LS in the actual imaging. In some embodiments, the optical scanner control unit 211A controls the optical scanner 42 in the provisional imaging according to a scan mode that differs for each adjustment target.

[0147] The correction control unit 211B changes the imaging conditions by controlling each unit of the ophthalmologic apparatus 1 based on the detection result of the interference light LC or the OCT image formed from the detection result. The correction control unit 211B changes the imaging conditions for OCT imaging by controlling at least one of the VCC lens 47, the optical path length changing unit 41, the reference driving unit 114A, and the polarization controllers 103 and 118.

[0148] In addition to the display control of the display device 3 as described above, the display control unit 211C can cause the display device 3 to display the control results of the correction control unit 211B.

[0149] Furthermore, the main control unit 211 performs processing to write data to the storage unit 212 and processing to read data from the storage unit 212 .

[0150] (Storage unit 212) The storage unit 212 stores various types of data. Examples of data stored in the storage unit 212 include image data of OCT images, image data of fundus images, and information about the subject's eye. The information about the subject's eye includes information about the subject, such as a patient ID and name, and information about the subject's eye, such as identification information for the left eye / right eye. The storage unit 212 also stores optometry data acquired in advance by an external device (for example, a refractometer or a subjective optometry device), as well as various programs and data for operating the ophthalmologic apparatus 1. The optometry data includes the astigmatic power and astigmatic axis angle of the subject's eye. The optometry data may further include the spherical power of the subject's eye. The optometry data may include at least one of the spherical power, astigmatic power, and astigmatic axis angle of the subject's eye.

[0151] At least a part of the data stored in the storage unit 212 may be stored in a storage unit provided outside the ophthalmic apparatus 1. For example, the ophthalmic apparatus 1 is communicably connected to a server device having a function of storing at least a part of the data via a network such as an in-hospital LAN (Local Area Network). Here, the ophthalmic apparatus 1 and the server device may be connected via a WAN (Wide Area Network) such as the Internet. Alternatively, the ophthalmic apparatus 1 and the server device may be connected via a network that combines a LAN and a WAN.

[0152] (Image forming unit 220) The image forming unit 220 forms image data of a tomographic image of the fundus oculi Ef based on the detection signal (interference signal) from the detector 125. That is, the image forming unit 220 forms an image of the subject's eye E based on the detection result of the interference light LC by the interference optical system. This processing includes processes such as noise removal (noise reduction), filtering, and FFT (Fast Fourier Transform), as in conventional swept-source type optical coherence tomography. The image data acquired in this manner is a data set including a group of image data formed by imaging the reflection intensity profiles in multiple A-lines (paths of each measurement light LS within the subject's eye E).

[0153] To improve image quality, multiple data sets collected by repeating the same scan pattern multiple times can be superimposed (averaged).

[0154] The image forming unit 220 is configured to include, for example, the circuit board described above. In this specification, "image data" and an "image" based on the image data may be considered to be the same thing. Also, a portion of the fundus Ef and an image thereof may be considered to be the same thing.

[0155] (Data processing unit 230) The data processing unit 230 performs various data processing (image processing) and analysis processing on the detection result of the interference light LC or the image formed by the image forming unit 220. For example, the data processing unit 230 performs various correction processing such as analysis of the signal-to-noise ratio of the interference signal, brightness correction of the image, dispersion correction, etc.

[0156] Furthermore, the data processing unit 230 performs various image processing and analysis processes on the images (fundus images, anterior segment images, etc.) obtained by the fundus camera unit 2.

[0157] The data processing unit 230 performs known image processing, such as interpolation processing that interpolates pixels between tomographic images, to form image data of a three-dimensional image of the fundus oculi Ef. Note that image data of a three-dimensional image means image data in which pixel positions are defined by a three-dimensional coordinate system. Image data of a three-dimensional image includes image data consisting of three-dimensionally arranged voxels. This image data is called volume data or voxel data, etc. When displaying an image based on the volume data, the data processing unit 230 performs rendering processing (volume rendering, MIP (Maximum Intensity Projection), etc.) on the volume data to form image data of a pseudo three-dimensional image as viewed from a specific line of sight. This pseudo three-dimensional image is displayed on a display device, such as the display unit 240A.

[0158] It is also possible to form stack data of multiple tomographic images as image data of a three-dimensional image. Stack data is image data obtained by arranging multiple tomographic images obtained along multiple scanning lines in a three-dimensional manner based on the positional relationship of the scanning lines. In other words, stack data is image data obtained by expressing multiple tomographic images that were originally defined using separate two-dimensional coordinate systems using a single three-dimensional coordinate system (i.e., embedding them in a single three-dimensional space).

[0159] The data processing unit 230 can align the fundus image and the OCT image. When the fundus image and the OCT image are acquired in parallel, the two optical systems are coaxial, so the fundus image and the OCT image, which are acquired (almost) simultaneously, can be aligned with each other using the optical axis of the imaging optical system 30 as a reference. Regardless of the timing of acquisition of the fundus image and the OCT image, it is also possible to align the OCT image and the fundus image by aligning the image obtained by projecting the OCT image onto the xy plane with the fundus image. This alignment method can also be applied when the optical system for acquiring the fundus image and the optical system for OCT measurement are not coaxial. Even when the two optical systems are not coaxial, if the relative positional relationship between the two optical systems is known, it is possible to perform alignment similar to the case of coaxial systems by referring to this relative positional relationship.

[0160] (Analysis Department 231) The data processing unit 230 includes an analysis unit 231 that performs the above-described analysis process. The analysis unit 231 analyzes at least the detection result of the interference light LC or the tomographic image formed by the image forming unit 220, and outputs an evaluation value (including a statistical value of the evaluation value) corresponding to the image quality (signal-to-noise ratio) of the tomographic image as the analysis result. The main control unit 211 (correction control unit 211B) can control at least one of the VCC lens 47, the OCT focusing drive unit 45A, the optical path length changer 41, and the polarization controllers 103 and 118 based on the analysis result obtained by the analysis unit 231. In particular, by having the analysis unit 231 analyze the detection result of the interference light LC obtained by deflecting the measurement light LS according to a deflection pattern corresponding to a circle scan or the tomographic image formed based on the detection result, it is possible to adjust the imaging conditions with high precision without being affected by eye movement, etc., even when the light source is fast.

[0161] As shown in FIG. 5, the analysis unit 231 includes an image division unit 231A and an image evaluation unit 231B.

[0162] (Image division section 231A) The image dividing unit 231A generates a plurality of divided images by dividing the tomographic image formed by the image forming unit 220 in a direction intersecting the A-scan direction. In some embodiments, the image dividing unit 231A generates a plurality of divided images by dividing the tomographic image in the B-scan direction (or a direction perpendicular to the A-scan direction). In some embodiments, the image dividing unit 231A generates a plurality of divided images by dividing the tomographic image in a direction intersecting the radial direction of a sector centered on the scan center position at a position corresponding to the pupil of the subject's eye E. The shapes or sizes of the plurality of divided images may be the same or different.

[0163] 6, 7A, and 7B are diagrams illustrating the operation of the image dividing unit 231A according to the embodiment. FIG. 6 shows divided images DP1 to DPn obtained by dividing a tomographic image IMG obtained by a circle scan into n (n is 1 or more, and preferably 4 or more). FIGS. 7A and 7B are schematic diagrams illustrating an example in which the image dividing unit 231A divides a tomographic image obtained by a circle scan into eight. FIGS. 7A and 7B are schematic diagrams illustrating the movement trajectory of the irradiation position of the measurement light LS by a circle scan that starts from the scan start position St.

[0164] In the tomographic image IMG, 1024 A-scan images are arranged in the B-scan direction (a direction perpendicular to the A-scan direction). The image dividing unit 231A divides the tomographic image IMG into n parts in the B-scan direction, for example, to generate divided images DP1 to DPn. In FIG. 6, the divided images DP1 to DPn are generated in a circle scan direction that moves in the order of temporal (T), superior (S), nasal (N), inferior (I), and temporal (T). The widths of the divided images DP1 to DPn in the B-scan direction may or may not be the same.

[0165] For example, in Fig. 7A, the tomographic image is divided so that at least one of the boundary lines of the divided images is oriented horizontally (x direction) or vertically (y direction). In contrast, in Fig. 7B, the tomographic image is divided so that the boundary lines of the divided images do not oriented horizontally or vertically. For example, by changing the scan start position St of the circle scan as shown in Fig. 7B, the tomographic image can be divided into eight parts based on the A scan line at the scan start position St. Alternatively, by changing the division position of the tomographic image without changing the scan start position St, the tomographic image can be divided into eight parts as shown in Fig. 7B.

[0166] As shown in Figure 7B, by dividing the tomographic image so that the boundaries of the divided images do not coincide in the horizontal and vertical directions, the sensitivity of the evaluation value to changes in the image quality of the divided images can be improved by taking advantage of the high probability that the image quality difference between the vertical and horizontal directions will be large in terms of astigmatism power and astigmatism axis angle. This makes it possible to adjust the imaging conditions with high precision.

[0167] In some embodiments, the image dividing unit 231A divides the tomographic image into an even number of parts, which allows the image evaluation unit 231B (described later) to evaluate the image quality based on the symmetry of the divided images that are point-symmetric with respect to the center position of the circle scan in the imaging region.

[0168] (Image evaluation unit 231B) The image evaluation unit 231B performs an analysis process on each of the multiple divided images generated by the image division unit 231A, and calculates an evaluation value corresponding to the obtained analysis result. That is, the image evaluation unit 231B calculates multiple evaluation values ​​for the multiple divided images.

[0169] The image evaluation unit 231B can calculate any evaluation value that quantitatively expresses image quality. Typically, the evaluation value is calculated so that the higher the image quality, the larger the value. The evaluation value calculation process executed by the image evaluation unit 231B may be any process. For example, the image evaluation unit 231B can execute processing using any known technology, such as signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), root-mean-square (RMS) granularity, Wiener spectrum, modulation transfer function (MTF), or quality index (QI).

[0170] In some embodiments, the image evaluation unit 231B applies a predetermined analysis process (e.g., segmentation process) to an evaluation region set for an image corresponding to a predetermined region. As a result, the image evaluation unit 231B identifies an image region (signal region) corresponding to the desired region (tissue) and other image regions (non-signal region). Next, the image evaluation unit 231B generates a histogram of luminance in the signal region and a histogram of luminance in the non-signal region. Subsequently, the image evaluation unit 231B calculates an evaluation value corresponding to 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, so that the evaluation value is 0 when both histograms completely overlap, and 100 when both histograms are completely separated. This evaluation calculation may include, for example, normalizing the two histograms, generating a probability distribution function, and calculating the evaluation value using a predetermined arithmetic expression.

[0171] Furthermore, the image evaluation unit 231B can calculate statistics of multiple evaluation values ​​for multiple divided images. Examples of the statistical values ​​include maximum, minimum, median, average, mode, range, variance, standard deviation, and values ​​of a predetermined evaluation formula using any of the above statistical values.

[0172] An example of the evaluation formula is the following formula (1), in which the value VCCQ of the evaluation formula increases as the total value of the evaluation values ​​of the multiple divided images increases and the variation in the evaluation values ​​of the multiple divided images decreases.

[0173]

number

[0174] In equation (1), the value VCCQ of the evaluation equation is the sum of the evaluation values ​​of a plurality of divided images divided by (the standard deviation of the plurality of evaluation values ​​+ 1).

[0175] The main control unit 211 (correction control unit 211B) can control at least one of the VCC lens 47, the OCT focusing drive unit 45A, the optical path length change unit 41, and the polarization controllers 103 and 118 based on the statistical value of the multiple evaluation values ​​calculated by the image evaluation unit 231B. For example, control of the VCC lens 47, etc. and OCT measurement are repeatedly performed so that the statistical value of the multiple evaluation values ​​becomes the maximum (minimum, or a desired value).

[0176] In some embodiments, the main control unit 211 controls at least one of the VCC lens 47, the OCT focusing drive unit 45A, the optical path length changer 41, and the polarization controllers 103 and 118 based on the value VCCQ of the evaluation formula obtained by equation (1). In this case, control of the VCC lens 47 and the like and OCT measurement are repeatedly performed so that the value VCCQ of the evaluation formula is maximized.

[0177] The main control unit 211 (display control unit 211C) causes the display device 3 or the display unit 240A (display means) to display the evaluation value or statistical value calculated by the image evaluation unit 231B. In some embodiments, the main control unit 211 causes the display device 3 or the like to display the evaluation value of at least one of the multiple divided images generated by the image dividing unit 231A in association with the divided image.

[0178] The data processing unit 230 that functions as described above is configured to include, for example, the above-mentioned processor, RAM, ROM, hard disk drive, circuit board, etc. A computer program that causes the microprocessor to execute the above functions is stored in advance in a storage device such as a hard disk drive.

[0179] (User Interface 240) The user interface 240 includes a display unit 240A and an operation unit 240B. The display unit 240A includes the display device of the arithmetic and control unit 200 and the display device 3 described above. The operation unit 240B includes the operation device of the arithmetic and control unit 200 described above. The operation unit 240B may include various buttons and keys provided on the housing of the ophthalmologic apparatus 1 or on the outside. For example, if the fundus camera unit 2 has a housing similar to that of a conventional fundus camera, the operation unit 240B may include a joystick, an operation panel, etc. provided on this housing. 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.

[0180] It should be noted that the display unit 240A and the operation unit 240B do not need to be configured as separate devices. For example, it is possible to use a device in which the display function and the operation function are integrated, such as a touch panel. In this case, the operation unit 240B is configured to include this touch panel and a computer program. The operation content on the operation unit 240B is input to the control unit 210 as an electrical signal. Furthermore, operations and information input may be performed using a graphical user interface (GUI) displayed on the display unit 240A and the operation unit 240B.

[0181] The display device 3 or the display unit 240A is an example of the "display means" according to this embodiment.

[0182] <Example of adjusting shooting conditions> As described above, in this embodiment, a provisional image is taken before the actual image is taken, and the image capturing conditions are adjusted for the actual image capture. The image capturing condition adjustments include adjustment of the VCC lens 47, adjustment of the OCT focusing lens 45, adjustment of the optical path length changing unit 41 or the corner cube 114, and adjustment of the polarization controllers 103 and 118.

[0183] (Example of adjusting VCC lens 47) First, the main controller 211 executes OCT measurement. In the OCT measurement, a circle scan is executed (i.e., the measurement light LS is deflected in the horizontal and vertical directions on a plane perpendicular to the optical axis of the interference optical system). The image forming unit 220 forms a tomographic image IMG as shown in FIG. 6 based on the detection result of the interference light LC obtained by the circle scan.

[0184] Next, the image dividing unit 231A divides the tomographic image IMG to generate a plurality of divided images, as shown in Fig. 6. The image evaluation unit 231B calculates an evaluation value for each of the generated divided images as described above. Subsequently, the image evaluation unit 231B calculates a statistical value of the plurality of evaluation values ​​calculated for the plurality of divided images. For example, the image evaluation unit 231B calculates the value of the evaluation formula shown in Equation (1) as the statistical value.

[0185] The main control unit 211 controls the VCC driving unit 47A based on the statistical value of the multiple evaluation values ​​calculated by the image evaluation unit 231B, thereby changing at least one of the cylindrical power and the cylindrical axis angle according to the statistical value of the multiple evaluation values ​​for the multiple divided images.

[0186] The main controller 211 repeatedly executes (repeates) OCT measurement, calculation of statistical values ​​for a tomographic image based on the detection result of interference light LC obtained by the OCT measurement, and control of the VCC driver 47A until the statistical values ​​satisfy a predetermined first termination condition. The first termination condition is a condition for locating the position of a minimum circle of confusion of a predetermined size or less (an intermediate position between the position of the anterior focal line where the inferior meridians converge and the position of the posterior focal line where the inferior meridians converge) at a predetermined position (for example, the fundus Ef (retina) or its vicinity). For example, the main controller 211 repeatedly executes OCT measurement, calculation of statistical values, and control of the VCC driver 47A so as to reduce the difference between the statistical values ​​and a first preset value for satisfying the first termination condition. The main controller 211 terminates adjustment of the VCC lens 47 when the relationship between the statistical values ​​and the first preset value satisfies a predetermined first relationship.

[0187] For example, the main control unit 211 repeatedly performs OCT measurements, calculates statistical values, and controls the VCC driving unit 47A so that the total value of the evaluation values ​​of the multiple divided images is high and the variation in the evaluation values ​​of the multiple divided images is small.

[0188] In some embodiments, the display control unit 211C causes the display device 3 or the display unit 240A to display at least one of the cylindrical power and the cylindrical axis angle before or after the change.

[0189] In some embodiments, the scan range of the circle scan performed in the above adjustment example is included in the imaging range for acquiring an OCT image. That is, the optical scanner control unit 211A controls the optical scanner 42 to scan a first scan range of the subject's eye E with the measurement light LS, and controls the VCC lens 47 (VCC driver 47A) based on the detection result of the interference light LC obtained by the interference optical system. Thereafter, the optical scanner control unit 211A controls the optical scanner 42 to scan a second scan range that includes the first scan range with the measurement light LS. The image forming unit 220 forms an OCT image (tomogram) of the subject's eye E based on the detection result of the interference light LC obtained by scanning the second scan range with the measurement light LS.

[0190] (Example of adjusting the OCT focusing lens 45) In some embodiments, the adjustment of the OCT focusing lens 45 is performed using a tomographic image (or the detection results of the interference light LC) obtained by circle scanning, similar to the adjustment of the VCC lens 47. That is, OCT measurement, calculation of the statistical value, and control of the OCT focusing driver 45A are repeatedly performed until a statistical value of multiple evaluation values ​​of multiple divided images obtained by dividing the tomographic image obtained by circle scanning satisfies a predetermined second termination condition. The second termination condition may be the same as the first termination condition. For example, the main controller 211 repeatedly performs OCT measurement, calculation of the statistical value, and control of the OCT focusing driver 45A so as to reduce the difference between the statistical value and a second preset value that satisfies the second termination condition. The main controller 211 terminates the adjustment of the OCT focusing lens 45 when the relationship between the statistical value and the second preset value satisfies a predetermined second relationship.

[0191] In some embodiments, the adjustment of the OCT focusing lens 45 is performed using a tomographic image (or the detection results of the interference light LC) obtained by a scan other than a circle scan (e.g., a line scan). That is, the OCT measurement, the calculation of the statistical value, and the control of the OCT focusing driver 45A are repeatedly performed until the statistical value of multiple evaluation values ​​of multiple divided images obtained by dividing the tomographic image obtained by line scan satisfies a predetermined second termination condition. The second termination condition may be the same as the first termination condition. For example, the main controller 211 repeatedly performs the OCT measurement, the calculation of the statistical value, and the control of the OCT focusing driver 45A so as to reduce the difference between the statistical value and a second preset value that satisfies the second termination condition. The main controller 211 terminates the adjustment of the OCT focusing lens 45 when the relationship between the statistical value and the second preset value satisfies the predetermined second relationship.

[0192] In some embodiments, the display controller 211C causes the display device 3 or the display unit 240A to display the position of the OCT focusing lens 45 before or after the change.

[0193] In some embodiments, the scan range of the scan performed in the above adjustment example is included in the imaging range for acquiring an OCT image. That is, the optical scanner control unit 211A controls the optical scanner 42 to scan a first scan range of the subject's eye E with the measurement light LS, and controls the OCT focusing lens 45 (OCT focusing drive unit 45A) based on the detection result of the interference light LC obtained by the interference optical system. Thereafter, the optical scanner control unit 211A controls the optical scanner 42 to scan a second scan range that includes the first scan range with the measurement light LS. The image forming unit 220 forms an OCT image (tomogram) of the subject's eye E based on the detection result of the interference light LC obtained by scanning the second scan range with the measurement light LS.

[0194] (Example of adjustment of optical path length changer 41 and corner cube 114) In some embodiments, the adjustment of the optical path length changer 41 or the corner cube 114 is performed using a tomographic image (or the detection result of the interference light LC) obtained by circle scanning, similar to the adjustment of the VCC lens 47. In this case, OCT measurement, calculation of the evaluation value, and control of the optical path length changer 41 or the reference driver 114A are repeatedly performed until a single evaluation value for the entire tomographic image obtained by circle scanning satisfies a predetermined third termination condition. The third termination condition is a condition for an image region corresponding to a site of interest (tissue) in the tomographic image to fall within a predetermined depth range. The image region corresponding to the site of interest in the tomographic image is identified by identifying a layer region corresponding to the desired site of interest from multiple layer regions obtained by performing a segmentation process on the tomographic image. For example, the main controller 211 repeatedly performs OCT measurement, calculation of statistical values, and control of the optical path length changer 41 or the corner cube 114 so as to reduce the difference between the evaluation value and a third predetermined value required to satisfy the third termination condition. When the relationship between the evaluation value and the third preset value reaches the predetermined third relationship, the main control unit 211 ends the adjustment of the optical path length changing unit 41 or the corner cube 114 .

[0195] In some embodiments, the adjustment of the optical path length changing unit 41 or the corner cube 114 is performed using a tomographic image (or the detection result of the interference light LC) obtained by line scanning. In this case, the OCT measurement, the calculation of the evaluation value, and the control of the optical path length changing unit 41 or the corner cube 114 are repeatedly performed until a single evaluation value of the entire tomographic image obtained by line scanning satisfies a predetermined third termination condition.

[0196] In some embodiments, the display control unit 211C causes the display device 3 or the display unit 240A to display information corresponding to the optical path length before or after the change.

[0197] In some embodiments, the scan range of the scan performed in the above adjustment example is included in the imaging range for acquiring an OCT image. That is, the optical scanner control unit 211A controls the optical scanner 42 to scan a first scan range of the subject's eye E with the measurement light LS, and controls the optical path length changer 41 or the corner cube 114 (reference driver 114A) based on the detection result of the interference light LC obtained by the interference optical system. Thereafter, the optical scanner control unit 211A controls the optical scanner 42 to scan a second scan range that includes the first scan range with the measurement light LS. The image forming unit 220 forms an OCT image (tomogram) of the subject's eye E based on the detection result of the interference light LC obtained by scanning the second scan range with the measurement light LS.

[0198] (Example of adjustment of polarization controllers 103 and 118) In some embodiments, the polarization controllers 103 and 118 are adjusted using a tomographic image (or the detection result of the interference light LC) obtained by circle scanning, similar to the adjustment of the VCC lens 47. In this case, OCT measurement, calculation of the evaluation value, and control of the polarization controllers 103 and 118 are repeatedly performed until a single evaluation value of the entire tomographic image obtained by circle scanning satisfies a predetermined fourth termination condition. The fourth termination condition is a condition for achieving the highest image quality of the entire tomographic image (e.g., the evaluation value reaches a maximum value). For example, the main controller 211 repeatedly performs OCT measurement, calculation of statistical values, and control of the polarization controllers 103 and 118 so as to reduce the difference between the evaluation value and a fourth preset value that satisfies the fourth termination condition. The main controller 211 terminates the adjustment of the polarization controllers 103 and 118 when the relationship between the evaluation value and the fourth preset value satisfies a predetermined fourth relationship.

[0199] In some embodiments, the polarization controllers 103 and 118 are adjusted using a tomographic image (or the detection result of the interference light LC) obtained by line scanning. In this case, the OCT measurement, the calculation of the evaluation value, and the control of the polarization controllers 103 and 118 are repeatedly performed until a single evaluation value of the entire tomographic image obtained by line scanning satisfies a predetermined fourth termination condition.

[0200] In some embodiments, the display control unit 211C causes the display device 3 or the display unit 240A to display information corresponding to the polarization state before or after the change.

[0201] In some embodiments, the scan range of the circle scan performed in the above adjustment example is included in the imaging range for acquiring an OCT image. That is, the optical scanner control unit 211A controls the polarization controllers 103 and 118 based on the detection result of the interference light LC obtained by the interference optical system by controlling the optical scanner 42 to scan a first scan range of the subject's eye E with the measurement light LS. Thereafter, the optical scanner control unit 211A controls the optical scanner 42 to scan a second scan range that includes the first scan range with the measurement light LS. The image forming unit 220 forms an OCT image (tomogram) of the subject's eye E based on the detection result of the interference light LC obtained by scanning the second scan range with the measurement light LS.

[0202] 8A and 8B are schematic diagrams showing the scan ranges of the circle scan performed in the provisional imaging and the scan performed in the actual imaging.

[0203] 8A, for example, circle scans CS1, CS2, and CS3 are performed in the provisional imaging within a scan range SA0 of the scan performed in the actual imaging. That is, the circle scans are performed so as to scan at least a portion of the scan range SA0. It is desirable that the circle scans performed in the provisional imaging be included within the scan range SA0 (for example, circle scans CS1 and CS2).

[0204] In some embodiments, as shown in Fig. 8B, circle scans CS1, CS11, CS12, CS12, and CS13 are performed to scan the center or corners of scan range SA0. Depending on the target of imaging condition adjustment, circle scans may be performed by changing the position within scan range SA0.

[0205] The spatial spread (speckle size) of the laser light's speckle noise becomes approximately equal to the diffraction limit r. The diffraction limit r is proportional to the central frequency λ of the laser light and inversely proportional to the numerical aperture of the objective lens 22. In some embodiments, when the number of A-lines in a circular scan line (diameter R) in the eye E to be examined during the execution of the circular scan is N, R×π / N < r is satisfied. At this time, it becomes possible to reduce the number of A-lines in the circular scan, and the imaging conditions can be adjusted with high precision in a shorter time.

[0206] Note that in each of the above adjustment examples, the case of forming a tomographic image has been described, but it is also possible to calculate an evaluation value from the detection result of the interference light LC.

[0207] [Operation Example] An operation example of the ophthalmic apparatus 1 according to the embodiment will be described.

[0208] FIG. 9, FIG. 10A, and FIG. 10B show flowcharts of operation examples of the ophthalmic apparatus 1 according to the embodiment. FIG. 9 represents a flowchart of an operation example of the ophthalmic apparatus 1 according to the embodiment. FIGS. 10A and 10B represent flowcharts of an operation example of step S6 in FIG. 9. In the storage unit 212, a computer program for realizing the processes shown in FIGS. 9, FIG. 10A, and FIG. 10B is stored. The main control unit 211 operates according to this computer program to execute the processes shown in FIGS. 9, FIG. 10A, and FIG. 10B.

[0209] (S1: Alignment) First, in a state where a fixation target is presented at a predetermined fixation position, the main control unit 211 performs alignment adjustment of the optical system with respect to the eye E to be examined. Examples of alignment adjustment include manual and automatic operations.

[0210] When performing alignment adjustment manually, the main controller 211 projects a pair of alignment indicators onto the subject's eye E using the alignment optical system 50. The display unit 240A displays a pair of alignment bright spots as received light images of these alignment indicators. The main controller 211 also causes the display unit 240A to display an alignment scale indicating positions to which the pair of alignment bright spots should be moved. The alignment scale is, for example, a parenthetical image.

[0211] When the positional relationship between the subject's eye E and the fundus camera unit 2 (objective lens 22) is appropriate, i.e., when the distance (working distance) between the subject's eye E and the fundus camera unit 2 is appropriate and the optical axis of the optical system of the fundus camera unit 2 and the eye axis (corneal apex position) of the subject's eye E are (almost) aligned, a pair of alignment bright spots are first imaged at predetermined positions (for example, midpoints between the corneal apex and the center of corneal curvature) and then projected onto the subject's eye E by a known method. The examiner (user) can adjust the alignment of the optical system with respect to the subject's eye E by moving the fundus camera unit 2 three-dimensionally so as to guide the pair of alignment bright spots into the alignment scale.

[0212] When performing automatic alignment adjustment, a movement mechanism 150 is used to move the fundus camera unit 2. The data processing unit 230 identifies the position of each alignment bright spot on the screen displayed on the display unit 240A and calculates the displacement between the identified position of each alignment bright spot and the alignment scale. The main control unit 211 moves the fundus camera unit 2 using the movement mechanism 150 so as to cancel this displacement. The position of each alignment bright spot can be identified, for example, by calculating the luminance distribution of each alignment bright spot and then calculating the center of gravity position based on this luminance distribution. Since the position of the alignment scale is constant, the desired displacement can be obtained, for example, by calculating the displacement between its center position and the center of gravity position. The movement direction and movement distance of the fundus camera unit 2 can be determined by referring to the unit movement distance in each of the predetermined x, y, and z directions (for example, the results of prior measurement of how much the alignment indicator moves in each direction when the fundus camera unit 2 is moved in each direction). The main control unit 211 generates a signal according to the determined movement direction and movement distance, and transmits this signal to the movement mechanism 150. As a result, the position of the optical system with respect to the eye E is automatically adjusted.

[0213] (S2: Initialize the VCC driver) Next, the main controller 211 initializes the VCC driver 47A. By initializing the VCC driver 47A, the cylindrical power of the VCC lens 47 is initialized. This makes it possible to avoid a situation in which adjustments of the various parts of the ophthalmologic apparatus 1 are performed in a state where an unintended cylindrical power is applied in steps S3 to S6, which will be described later.

[0214] (S3: Adjust depth position) Next, the main controller 211 adjusts the depth position at which the image region corresponding to the site of interest in the subject's eye E is rendered so that the image region corresponding to the site of interest falls within a predetermined depth range in the tomographic image.

[0215] Specifically, the main control unit 211 turns on the light source unit 101 and controls the optical scanner 42 to deflect the measurement light LS according to a deflection pattern corresponding to line scanning, thereby performing OCT measurement.

[0216] Next, the main control unit 211 causes the image forming unit 220 to form a tomographic image based on the detection result of the interference light LC obtained by the line scan.

[0217] Next, the main controller 211 controls the analyzer 231 to perform segmentation processing on the tomographic image and identify multiple layer regions. The analyzer 231 identifies a desired first layer region on the shallower side and a desired second layer region on the deeper side from the identified multiple layer regions. The main controller 211 controls the optical path length changer 41 or the reference driver 114A so that an image region corresponding to the region between the identified first and second layer regions falls within a predetermined depth range in the tomographic image.

[0218] In some embodiments, step S3 repeats the line scan and layer region identification process so that the image region corresponding to the region between the first layer region and the second layer region falls within the desired depth range in the tomographic image.

[0219] In some embodiments, in step S3, the detection result of the interference light LC is obtained by circle scanning.

[0220] (S4: Focus adjustment) Next, the main control unit 211 performs focus adjustment.

[0221] Specifically, the main control unit 211 turns on the light source unit 101 and controls the optical scanner 42 to deflect the measurement light LS according to a deflection pattern corresponding to the circle scan, thereby performing OCT measurement.

[0222] Next, the main controller 211 causes the image forming part 220 to form a tomographic image based on the detection result of the interference light LC obtained by the circle scan.

[0223] Subsequently, the main controller 211 causes the image divider 231A to generate a plurality of divided images by dividing the formed tomographic image in the B-scan direction. The image divider 231A generates divided images DP1 to DP8 by dividing the tomographic image into eight in the B-scan direction, for example.

[0224] Next, the main control unit 211 causes the image evaluation unit 231B to calculate an evaluation value corresponding to the image quality of each of the generated divided images DP1 to DP8. As described above, the image evaluation unit 231B calculates an evaluation value for each of the generated divided images. Furthermore, the image evaluation unit 231B calculates a statistical value of the multiple evaluation values ​​calculated for the multiple divided images. For example, the image evaluation unit 231B calculates the value VCCQ of the evaluation formula shown in equation (1) as the statistical value.

[0225] The main controller 211 controls the OCT focusing driver 45A based on the statistical value of the multiple evaluation values ​​(value VCCQ of the evaluation formula) calculated by the image evaluator 231B, thereby moving the OCT focusing lens 45 to a position corresponding to the statistical value of the multiple evaluation values.

[0226] The OCT measurement, the calculation of the statistical value, and the control of the OCT focus driver 45A are repeatedly performed until the statistical value of the multiple evaluation values ​​satisfies a predetermined termination condition. For example, the main controller 211 repeatedly performs the OCT measurement, the calculation of the statistical value, and the control of the OCT focus driver 45A so as to reduce the difference between the statistical value and a preset value that satisfies the predetermined termination condition. The main controller 211 ends the adjustment of the OCT focus lens 45 when the relationship between the statistical value and the preset value reaches a predetermined relationship.

[0227] (S5: Polarization adjustment) Next, the main controller 211 performs polarization adjustment, in which at least one of the polarization state of the measurement light LS and the polarization state of the reference light LR is adjusted.

[0228] Specifically, the main control unit 211 turns on the light source unit 101 and controls the optical scanner 42 to deflect the measurement light LS according to a deflection pattern corresponding to the circle scan, thereby performing OCT measurement.

[0229] Next, the main controller 211 causes the image forming part 220 to form a tomographic image based on the detection result of the interference light LC obtained by the circle scan.

[0230] Subsequently, the main controller 211 causes the image divider 231A to generate a plurality of divided images by dividing the formed tomographic image in the B-scan direction. The image divider 231A generates divided images DP1 to DP8 by dividing the tomographic image into eight in the B-scan direction, for example.

[0231] Next, the main control unit 211 causes the image evaluation unit 231B to calculate an evaluation value corresponding to the image quality of each of the generated divided images DP1 to DP8. As described above, the image evaluation unit 231B calculates an evaluation value for each of the generated divided images. Furthermore, the image evaluation unit 231B calculates a statistical value of the multiple evaluation values ​​calculated for the multiple divided images. For example, the image evaluation unit 231B calculates the value VCCQ of the evaluation formula shown in equation (1) as the statistical value.

[0232] The main control unit 211 controls the polarization controller 103 or the polarization controller 118 so that the statistical value of the multiple evaluation values ​​calculated by the image evaluation unit 231B (the value VCCQ of the evaluation formula) is maximized. As a result, at least one of the polarization state of the measurement light LS and the polarization state of the reference light LR is changed according to the statistical value of the multiple evaluation values. In some embodiments, after adjusting one of the polarization controller 103 and the polarization controller 118, the other is adjusted.

[0233] Until the statistical value of the plurality of evaluation values ​​satisfies a predetermined termination condition, the OCT measurement, the calculation of the statistical value, and the control of the polarization controllers 103 and 118 are repeatedly performed. For example, the main controller 211 repeatedly performs the OCT measurement, the calculation of the statistical value, and the control of the polarization controllers 103 and 118 so as to reduce the difference between the statistical value and a preset value that satisfies the predetermined termination condition. The main controller 211 ends the adjustment of the polarization controllers 103 and 118 when the relationship between the statistical value and the preset value satisfies a predetermined relationship.

[0234] (S6: Adjust the VCC lens) Next, the main control unit 211 adjusts the VCC lens 47.

[0235] Step S6 will be described in detail later.

[0236] (S7: OCT measurement) When the photographing conditions are adjusted by adjusting the adjustments of the various parts of the ophthalmologic apparatus 1 in steps S2 to S6, the main controller 211 executes OCT measurement for the actual photographing.

[0237] Specifically, the main controller 211 turns on the light source unit 101 and controls the optical scanner 42 to deflect the measurement light LS according to a deflection pattern corresponding to a desired scan mode, thereby performing OCT measurement. In step S7, for example, a line scan, a circle scan, a radial scan, a multi-line cross scan, or a 3D scan is performed.

[0238] Next, the main control unit 211 causes the image forming unit 220 to form a tomographic image based on the detection result of the interference light LC obtained by scanning the deflection pattern corresponding to the desired scan mode.

[0239] In step S7, an image of the eye E to be examined is displayed live using the formed tomographic image, or a three-dimensional image is formed.

[0240] This is the end of the operation of the ophthalmologic apparatus 1 (END).

[0241] In step S6 of FIG. 9, for example, the flow shown in FIGS. 10A and 10B is executed.

[0242] Fig. 11 is a diagram illustrating the operation of step S6 in Fig. 9. Fig. 11 schematically shows the axial direction of cylindrical lens 471 (VCC1) and the axial direction of cylindrical lens 472 (VCC2). For ease of explanation, in Fig. 11, the horizontal axis angle is represented as 0 degrees, the vertical (upward) axis angle is represented as 90 degrees, and the rotation direction from 0 degrees to 90 degrees is considered to be the positive direction.

[0243] (S11: Set cylinder power to the initial value) First, the main control unit 211 controls the VCC driving unit 47A to rotate the cylindrical lenses 471 and 472 and set the cylindrical power (θp in FIG. 11) to an initial value.

[0244] Specifically, the main controller 211 controls the VCC driver 47A to set the axial direction of the cylindrical lens 471 and the axial direction of the cylindrical lens 472 to 0 degree. After that, the main controller 211 controls the VCC driver 47A to change the axial direction of the cylindrical lens 471 and the axial direction of the cylindrical lens 472, and sets the predetermined cylindrical power θp to θp' (θp = θp').

[0245] Next, the main control unit 211 executes control to determine the cylindrical axis angle of the VCC lens 47 (steps S12 to S16).

[0246] (S12: OCT measurement) Next, the main control unit 211 controls the OCT unit 100 and the like to perform OCT measurement.

[0247] Specifically, the main control unit 211 turns on the light source unit 101 and controls the optical scanner 42 to deflect the measurement light LS according to a deflection pattern corresponding to the circle scan, thereby performing OCT measurement.

[0248] (S13: Evaluate OCT images) Next, the main controller 211 causes the image forming part 220 to form an OCT image (tomographic image) based on the detection result of the interference light LC obtained in step S12.

[0249] Next, the main controller 211 causes the image divider 231A to generate divided images DP1 to DP8 by dividing the formed OCT image in the B-scan direction.

[0250] Next, the main control unit 211 causes the image evaluation unit 231B to calculate an evaluation value corresponding to the image quality of each of the generated divided images DP1 to DP8. As described above, the image evaluation unit 231B calculates an evaluation value for each of the generated divided images. Furthermore, the image evaluation unit 231B calculates a statistical value of the evaluation values ​​calculated for the divided images DP1 to DP8. For example, the image evaluation unit 231B calculates the value VCCQ of the evaluation formula shown in equation (1) as the statistical value.

[0251] (S14:Next?) Next, the main controller 211 determines whether to further change the cylindrical axis angle and re-evaluate the OCT image. For example, the main controller 211 repeats re-evaluation of the OCT image so as to evaluate the OCT image for cylindrical axis angles θa ranging from 0 degrees to 180 degrees.

[0252] When it is determined in step S14 that the OCT image is to be re-evaluated (step S14: Y), the operation of the ophthalmic apparatus 1 proceeds to step S15. On the other hand, when it is determined in step S14 that the OCT image is not to be re-evaluated (step S14: N), the operation of the ophthalmic apparatus 1 proceeds to step S16.

[0253] (S15: Change the cylinder axis angle) When it is determined in step S14 that the OCT image is to be re-evaluated (step S14: Y), the main control unit 211 controls the VCC driving unit 47A to change the axial directions of the cylindrical lenses 471 and 472 while maintaining the cylindrical power θp.

[0254] Specifically, the main control unit 211 controls the VCC driving unit 47A to change the cylinder axis angle by a predetermined number of steps in the positive direction.

[0255] The operation of the ophthalmologic apparatus 1 proceeds to step S12.

[0256] Steps S12 to S15 are repeatedly executed for the cylinder axis angle θa in the range from 0 degrees to 180 degrees.

[0257] (S16: Determine the cylinder axis angle) When it is determined in step S14 that the OCT image is not to be re-evaluated (step S14: N), the main controller 211 determines the cylinder axis angle.

[0258] Specifically, the main control unit 211 identifies the maximum value of the statistical values ​​calculated in step S13, which is repeatedly executed for the cylinder axis angle θa in the range from 0 to 180 degrees, and identifies the cylinder axis angle θa' when the statistical value is maximum. The main control unit 211 determines the identified cylinder axis angle as the cylinder axis angle θa (θa = θa').

[0259] Next, the main control unit 211 executes control to determine the cylindrical power of the VCC lens 47 (steps S17 to S22).

[0260] (S17: Set cylinder power) Next, the main control unit 211 controls the VCC driving unit 47A to rotate the cylindrical lenses 471 and 472 to set a predetermined cylindrical power.

[0261] For example, the main control unit 211 controls the VCC driving unit 47A to rotate the cylindrical lens 471 by +θp′ / 2 and rotate the cylindrical lens 472 by −θp′ / 2. As a result, the cylindrical axis angle θa1 of the cylindrical lens 471 (VCC1) is expressed by equation (2).

[0262]

number

[0263] Similarly, the cylindrical axis angle θa2 of the cylindrical lens 472 (VCC2) is expressed as in equation (3).

[0264]

number

[0265] As shown in FIG. 11, the cylindrical power θp is determined by the angle formed by the cylindrical axis angles θa1 and θa2.

[0266] (S18: OCT measurement) Next, the main controller 211 controls the OCT unit 100 and the like to perform OCT measurement, similarly to step S12.

[0267] (S19: Evaluate OCT images) Next, similarly to step S13, the main controller 211 causes the image forming part 220 to form an OCT image (tomographic image) based on the detection result of the interference light LC obtained in step S18.

[0268] Next, the main controller 211 causes the image divider 231A to generate divided images DP1 to DP8 by dividing the formed OCT image in the B-scan direction.

[0269] Next, the main control unit 211 causes the image evaluation unit 231B to calculate an evaluation value corresponding to the image quality of each of the generated divided images DP1 to DP8. As described above, the image evaluation unit 231B calculates an evaluation value for each of the generated divided images. Furthermore, the image evaluation unit 231B calculates a statistical value of the evaluation values ​​calculated for the divided images DP1 to DP8. For example, the image evaluation unit 231B calculates the value VCCQ of the evaluation formula shown in equation (1) as the statistical value.

[0270] (S20:Next?) Next, the main controller 211 determines whether to further change the cylindrical power and re-evaluate the OCT image. For example, the main controller 211 repeats re-evaluation of the OCT image so as to evaluate the OCT image for cylindrical powers θp ranging from 0 degrees to 90 degrees.

[0271] When it is determined in step S20 that the OCT image is to be re-evaluated (step S20: Y), the operation of the ophthalmic apparatus 1 proceeds to step S21. On the other hand, when it is determined in step S20 that the OCT image is not to be re-evaluated (step S20: N), the operation of the ophthalmic apparatus 1 proceeds to step S22.

[0272] (S21: Change cylinder power) When it is determined in step S20 that the OCT image should be re-evaluated (step S20: Y), the main control unit 211 controls the VCC driving unit 47A to change the axial directions of the cylindrical lenses 471 and 472 while maintaining the cylindrical axis angle θa.

[0273] Specifically, the main control unit 211 controls the VCC driving unit 47A to change at least one of the axial directions of the cylindrical lens 471 and the cylindrical lens 472, thereby changing the cylindrical power by a predetermined step.

[0274] The operation of the ophthalmologic apparatus 1 proceeds to step S18.

[0275] Steps S18 to S21 are repeatedly executed for cylindrical power θp ranging from 0 degrees to 90 degrees.

[0276] (S22: Determine cylinder power) When it is determined in step S20 that the OCT image is not to be re-evaluated (step S20: N), the main controller 211 determines the cylindrical power.

[0277] Specifically, the main control unit 211 identifies the maximum value of the statistical values ​​calculated in step S19, which is repeatedly executed for cylindrical powers θp in the range from 0 degrees to 90 degrees, and identifies the cylindrical power θp" when the statistical value is maximum.The main control unit 211 determines the identified cylindrical power as the cylindrical power θp (θp=θp").

[0278] (S23: Adjust the VCC lens) Subsequently, the main control unit 211 controls the VCC driving unit 47A to adjust the VCC lens 47 using the cylindrical axis angle θa′ determined in step S16 and the cylindrical power θp″ determined in step S22.

[0279] Specifically, the main control unit 211 controls the VCC driving unit 47A to set the cylindrical axis angle θa1 of the cylindrical lens 471 as shown in equation (4).

[0280]

number

[0281] Similarly, the main control unit 211 controls the VCC driving unit 47A to set the cylindrical axis angle θa2 of the cylindrical lens 472 as shown in equation (5).

[0282]

number

[0283] This is the end of the flow of step S6 in FIG. 9 (END).

[0284] As described above, since at least the VCC lens 47 is adjusted using a circle scan, horizontal and vertical information on a plane perpendicular to the optical axis of the interference optical system can be obtained in a shorter time than in the case of a raster scan (or two or more line scans). Therefore, horizontal and vertical information can be obtained in a shorter time, and astigmatism can be corrected from the obtained horizontal and vertical information. As a result, even if the light source is fast, astigmatism can be corrected with high precision without being affected by eye movement, etc.

[0285] Furthermore, since the scan mode is changed for each adjustment target for which the imaging conditions are determined, it is possible to change the imaging conditions in the optimal scan mode according to the adjustment target, thereby enabling the imaging conditions to be adjusted with high precision in a shorter time.

[0286] It should be noted that the embodiment is not limited to the order of steps in Fig. 9. For example, the order of execution of steps S4 to S6 can be changed arbitrarily.

[0287] In some embodiments, a program for causing a computer to execute the above-described method for controlling an ophthalmic apparatus is provided. Such a program can be stored on any non-transitory computer-readable recording medium. The recording medium may be an electronic medium using magnetic, optical, magneto-optical, or semiconductor materials. Typically, the recording medium is a magnetic tape, a magnetic disk, an optical disk, a magneto-optical disk, a flash memory, a solid-state drive, or the like. The program can also be transmitted and received via a network such as the Internet or a LAN.

[0288] [effect] An ophthalmic apparatus, a control method for the ophthalmic apparatus, and a program according to an embodiment will be described.

[0289] An ophthalmic apparatus (1) according to some embodiments includes an interference optical system (an optical system included in the OCT unit 100, an optical scanner 42, and a VCC lens 47), an optical scanner control unit (211A), and a correction control unit (211B). The interference optical system includes an astigmatism correction optical element (the VCC lens 47) and an optical scanner (42). The interference optical system splits light (L0) from a light source (light source unit 101) into measurement light (LS) and reference light (LR), irradiates the measurement light onto the subject's eye (E) via the astigmatism correction optical element and the optical scanner, and detects interference light (LC) between return light of the measurement light from the subject's eye and the reference light. The optical scanner control unit controls the optical scanner to deflect the measurement light in horizontal and vertical directions in a plane perpendicular to the optical axis of the interference optical system. The correction control unit controls the astigmatism correction optical element to correct astigmatism based on the detection result of the interference light obtained by the interference optical system.

[0290] With this configuration, horizontal and vertical information on a plane perpendicular to the optical axis of the interference optical system can be obtained in a shorter time than with raster scanning or two or more line scans, and astigmatism can be corrected. As a result, even when the light source is fast, astigmatism can be corrected with high precision without being affected by eye movement, etc.

[0291] Some embodiments include an analyzer (231) that analyzes the detection result of the interference light. The correction controller controls the astigmatism correction optical element based on the analysis result obtained by the analyzer.

[0292] With this configuration, it is possible to correct astigmatism with higher precision in accordance with the detection result of the interference light.

[0293] Some embodiments include an image forming unit (220) that forms an image of the subject's eye based on the detection result of the interference light. The analysis unit analyzes each of a plurality of divided images obtained by dividing the image in a direction intersecting the A-scan direction. The correction control unit controls the astigmatism correction optical element based on a plurality of analysis results for the plurality of divided images.

[0294] With this configuration, the image of the subject's eye is divided in a direction intersecting the A-scan direction to generate multiple divided images, and the astigmatism correction optical element is controlled based on multiple analysis results obtained by analyzing the divided images, so that the astigmatism correction optical element can be controlled based on more detailed analysis results of the image of the subject's eye. This makes it possible to adjust the astigmatism correction optical element with high accuracy in a short amount of time using simple processing.

[0295] In some embodiments, the analysis unit calculates an evaluation value corresponding to the analysis result for each of the divided images, and the correction control unit controls the astigmatism correction optical element based on a statistical value of the multiple evaluation values ​​for the multiple divided images.

[0296] With this configuration, an evaluation value is calculated for each divided image, and the astigmatism correction optical element is controlled based on the statistical value of the multiple evaluation values ​​for the multiple divided images, making it possible to adjust the astigmatism correction optical element with high precision in a short amount of time and with simpler processing.

[0297] Some embodiments include a first display control unit (display control unit 211C) that causes a display means (display device 3, display unit 240A) to display the evaluation value or statistical value calculated by the analysis unit.

[0298] With this configuration, it is possible to easily identify divided images with different evaluation values ​​from among a plurality of divided images, and it becomes easy to identify factors that determine whether the adjustment of the astigmatism correction optical member is appropriate.

[0299] In some embodiments, the optical scanner control unit controls the astigmatism correction optical member based on a detection result of the interference light obtained by the interference optical system by controlling the optical scanner to scan a first scan range of the test eye with the measurement light, and then controls the optical scanner to scan a second scan range containing the first scan range with the measurement light. The image forming unit forms an image of the test eye based on the detection result of the interference light obtained by scanning the second scan range with the measurement light.

[0300] With this configuration, it is possible to control the astigmatism correction optical element in consideration of the detection result of the interference light in the second scan range for forming an image of the subject's eye, and therefore it is possible to correct astigmatism for the main imaging (main measurement) with high precision. Also, by making the first scan range narrower than the second scan range, it is possible to further shorten the scan time of the first scan range, and it becomes possible to correct astigmatism with higher precision.

[0301] In some embodiments, the optical scanner control unit corrects the position of the second scan range based on tracking information obtained by tracking the interference optical system with respect to the movement of the test eye, and controls the optical scanner to scan the corrected second scan range with the measurement light.

[0302] According to this configuration, it becomes possible to correct astigmatism with higher precision while following the movement of the subject's eye.

[0303] Some embodiments include a second display control unit (display control unit 211C) that causes a display means (display device 3, display unit 240A) to display an image of the test eye formed based on the detection results of the interference light obtained by scanning the second scan range with the measurement light.

[0304] According to this configuration, it is possible to provide an ophthalmologic apparatus capable of displaying on the display means an image of the eye to be examined in which astigmatism has been corrected with high accuracy.

[0305] In some embodiments, the interference optical system includes a focus position changing member (OCT focusing lens 45, OCT focusing driver 45A) that is disposed in the optical path of the measurement light and can change the focal position of the measurement light. The correction controller controls the focus position changing member based on the detection result of the interference light obtained by the interference optical system.

[0306] According to this configuration, it is possible to provide an ophthalmic apparatus that can correct astigmatism with high accuracy in a short time and adjust the focal position of the measurement light.

[0307] In some embodiments, the interference optical system includes an optical path length changing member (optical path length changing unit 41, corner cube 114, and reference driver 114A) disposed in the optical path of the measurement light or the optical path of the reference light, which changes the optical path length difference between the measurement light and the reference light. The optical scanner control unit controls the optical scanner to deflect the measurement light in a direction intersecting the optical axis of the interference optical system. The correction control unit controls the optical path length changing member based on the detection result of the interference light obtained by the interference optical system.

[0308] According to this configuration, it is possible to provide an ophthalmic apparatus that can correct astigmatism with high accuracy in a short time and adjust the optical path length difference between the measurement light and the reference light.

[0309] In some embodiments, the interference optical system includes a polarization state changing member (polarization controller 103, 118) disposed in the optical path of the measurement light or the optical path of the reference light, which changes the polarization state of the measurement light or the polarization state of the reference light. The optical scanner control unit controls the optical scanner to deflect the measurement light in a direction intersecting the optical axis of the interference optical system. The correction control unit controls the polarization state changing member based on the detection result of the interference light obtained by the interference optical system.

[0310] According to this configuration, it is possible to provide an ophthalmic apparatus that can correct astigmatism with high accuracy in a short time and adjust the optical path length difference between the measurement light and the reference light.

[0311] In some embodiments, the astigmatism correcting optic has variable cylinder power and cylinder axis angle.

[0312] According to this configuration, by changing the cylindrical power and the cylindrical axis angle, it becomes possible to correct astigmatism with high precision in a short time.

[0313] In some embodiments, the astigmatism correcting optic comprises a variable cross cylinder lens.

[0314] According to such a configuration, by using a variable cross-cylinder lens, it becomes possible to correct the aberration with high precision at low cost and in a short time.

[0315] Some embodiments include a third display control unit (display control unit) that causes a display means (display device 3, display unit 240A) to display at least one of the cylindrical power and the cylindrical axis angle.

[0316] According to such a configuration, it becomes possible to easily grasp the state of adjustment of the aberration.

[0317] In some embodiments, the optical scanner control unit deflects the measurement light in the horizontal and vertical directions by controlling the optical scanner so as to deflect the measurement light in a circular shape.

[0318] According to such a configuration, the scan speed can be made substantially constant over the entire scan area, and a uniform scan result can be obtained over the entire scan area. As a result, it becomes possible to correct the aberration with high precision based on the uniform scan result. Further, for example, since it is less likely to be affected by regular reflection from the vertex of the objective lens, it becomes possible to correct the aberration with high precision based on an artifact-free scan result.

[0319] In some embodiments, when the diffraction limit is r, the diameter of the circular scan line in the eye to be examined is R, and the number of A lines in the scan line is N, R×π / N < r is satisfied.

[0320] According to such a configuration, it becomes possible to reduce the number of A lines without degrading the accuracy of the scan for adjusting the imaging conditions (measurement conditions), and it becomes possible to correct the aberration with high precision in a shorter time.

[0321] A control method for an ophthalmic apparatus (1) according to some embodiments is a control method for an ophthalmic apparatus including an interference optical system (an optical system included in the OCT unit 100, an optical scanner 42, and a VCC lens 47), an optical scanner control unit (211A), and a correction control unit (211B). The interference optical system includes an astigmatism correction optical element (the VCC lens 47) and an optical scanner (42). The interference optical system splits light (L0) from a light source (light source unit 101) into measurement light (LS) and reference light (LR), irradiates the measurement light onto the subject's eye (E) via the astigmatism correction optical element and the optical scanner, and detects interference light (LC) between return light of the measurement light from the subject's eye and the reference light. The control method for an ophthalmic device includes a first control step of controlling an optical scanner to deflect measurement light in horizontal and vertical directions in a plane perpendicular to the optical axis of the interference optical system, and a second control step of controlling an astigmatism correction optical element to correct astigmatism based on the detection result of interference light obtained by the interference optical system by irradiating the measurement light deflected in the first control step onto the subject's eye.

[0322] This method allows for obtaining horizontal and vertical information and correcting astigmatism in a shorter time than raster scanning or two or more line scans. This makes it possible to correct astigmatism with high precision, without being affected by eye movement, even when the light source is fast.

[0323] Some embodiments include an analyzing step of analyzing the detection result of the interference light, and a second control step of controlling the astigmatism correction optical member based on the analysis result obtained in the analyzing step.

[0324] According to this method, it becomes possible to correct astigmatism with higher precision in accordance with the detection result of the interference light.

[0325] Some embodiments include a first image forming step of forming an image of the subject's eye based on the detection result of the interference light, an analysis step of analyzing each of a plurality of divided images obtained by dividing the image in a direction intersecting the A-scan direction, and a second control step of controlling the astigmatism correction optical element based on a plurality of analysis results corresponding to the plurality of divided images.

[0326] According to this method, the image of the subject's eye is divided in a direction intersecting the A-scan direction to generate a plurality of divided images, and the astigmatism correction optical element is controlled based on a plurality of analysis results obtained by analyzing the divided images, so that the astigmatism correction optical element can be controlled based on more detailed analysis results of the image of the subject's eye. This makes it possible to adjust the astigmatism correction optical element with high accuracy in a short amount of time using simple processing.

[0327] In some embodiments, the analyzing step calculates an evaluation value corresponding to the analysis result for each of the divided images, and the second control step controls the astigmatism correction optical member based on a statistical value of the evaluation values ​​for the plurality of divided images.

[0328] According to this method, an evaluation value is calculated for each divided image, and the astigmatism correction optical element is controlled based on the statistical value of the multiple evaluation values ​​for the multiple divided images, making it possible to adjust the astigmatism correction optical element with high precision in a short amount of time and with simpler processing.

[0329] Some embodiments include a first display control step of causing a display means (the display device 3, the display unit 240A) to display the evaluation value or the statistical value calculated in the analysis step.

[0330] According to this method, it is possible to easily identify divided images with different evaluation values ​​from among a plurality of divided images, and it becomes easy to identify factors that determine whether the adjustment of the astigmatism correction optical member is appropriate.

[0331] In some embodiments, the method includes a third control step and a second image formation step. In the third control step, the second control step controls the astigmatism correction optical member based on the detection result of interference light obtained by scanning a first scan range of the test eye with the measurement light in the first control step, and then controls the optical scanner to scan a second scan range containing the first scan range with the measurement light. In the second image formation step, an image of the test eye is formed based on the detection result of interference light obtained by scanning the second scan range with the measurement light in the third control step.

[0332] According to this method, it is possible to control the astigmatism correction optical element in consideration of the detection result of the interference light in the second scan range for forming an image of the subject's eye, and therefore it is possible to correct astigmatism for the actual photography (actual measurement) with high precision. Furthermore, by making the first scan range narrower than the second scan range, it is possible to further shorten the scan time of the first scan range, and it becomes possible to correct astigmatism with higher precision.

[0333] In some embodiments, the second control step corrects the position of the second scan range based on tracking information obtained by tracking the interference optical system with respect to the movement of the test eye, and controls the optical scanner to scan the corrected second scan range with the measurement light.

[0334] According to this method, it becomes possible to correct astigmatism with higher precision while following the movement of the subject's eye.

[0335] Some embodiments include a second display control step of displaying on a display means (display device 3, display unit 240A) an image of the test eye formed based on the detection results of the interference light obtained by scanning the second scan range with the measurement light.

[0336] According to this method, it becomes possible to display on the display means an image of the eye to be examined in which astigmatism has been corrected with high accuracy.

[0337] In some embodiments, the interference optical system includes a focus position changing member (OCT focusing lens 45, OCT focusing driver 45A) that is disposed in the optical path of the measurement light and can change the focal position of the measurement light. The control method for an ophthalmologic apparatus further includes a fourth control step of controlling the focus position changing member based on the detection result of the interference light obtained by the interference optical system.

[0338] According to this method, it becomes possible to correct astigmatism with high precision in a short time and adjust the focal position of the measuring light.

[0339] In some embodiments, the interference optical system is arranged in the optical path of the measurement light or the optical path of the reference light and includes an optical path length changing member (optical path length changing unit 41, corner cube 114, and reference drive unit 114A) that changes the optical path length difference between the measurement light and the reference light. The control method for an ophthalmic apparatus includes a fifth control step of controlling the optical scanner to deflect the measurement light in a direction intersecting the optical axis of the interference optical system, and a sixth control step of controlling the optical path length changing member based on a detection result of the interference light obtained by the interference optical system by irradiating the test eye with the measurement light deflected in the fifth control step.

[0340] According to this method, it is possible to correct astigmatism with high precision in a short time and adjust the optical path length difference between the measurement light and the reference light.

[0341] In some embodiments, the interference optical system includes a polarization state changing member (polarization controller 103, 118) that is arranged in the optical path of the measurement light or the optical path of the reference light and changes the polarization state of the measurement light or the polarization state of the reference light. The control method for an ophthalmic apparatus includes a seventh control step of controlling the optical scanner to deflect the measurement light in a direction intersecting the optical axis of the interference optical system, and an eighth control step of controlling the polarization state changing member based on a detection result of the interference light obtained by the interference optical system by irradiating the test eye with the measurement light deflected in the seventh control step.

[0342] According to this method, it is possible to correct astigmatism with high precision in a short time and adjust the optical path length difference between the measurement light and the reference light.

[0343] In some embodiments, the astigmatism correcting optic has variable cylinder power and cylinder axis angle.

[0344] According to this method, by changing the cylindrical power and the cylindrical axis angle, it becomes possible to correct astigmatism with high accuracy in a short time.

[0345] In some embodiments, the astigmatism correcting optic comprises a variable cross cylinder lens.

[0346] According to this method, by using a variable cross cylinder lens, it becomes possible to correct astigmatism with high accuracy at low cost and in a short time.

[0347] Some embodiments include a third display control step of causing the display means (the display device 3, the display unit 240A) to display at least one of the cylindrical power and the cylindrical axis angle.

[0348] According to this method, it becomes possible to easily grasp the state of astigmatism adjustment.

[0349] In some embodiments, the first control step deflects the measurement light in horizontal and vertical directions by controlling the optical scanner to deflect the measurement light in a circular shape.

[0350] This method allows the scanning speed to be kept nearly constant across the entire scan area, resulting in uniform scan results across the entire scan area. As a result, astigmatism can be corrected with high accuracy based on the uniform scan results. Furthermore, since the method is less susceptible to the effects of specular reflection from the vertex of the objective lens, for example, astigmatism can be corrected with high accuracy based on artifact-free scan results.

[0351] In some embodiments, when the diffraction limit is r, the diameter of the circular scan line in the eye to be examined is R, and the number of A-lines in the scan line is N, R×π / N < r is satisfied.

[0352] According to such a method, it becomes possible to reduce the number of A-lines without degrading the accuracy of the scan for adjusting the imaging conditions (measurement conditions), and it becomes possible to correct the aberration with high accuracy in a shorter time.

[0353] A program according to some embodiments causes a computer to execute each step of the control method of the ophthalmic device described in any of the above.

[0354] According to such a program, it is possible to acquire horizontal and vertical information in a plane perpendicular to the optical axis of the interference optical system in a shorter time than raster scanning or two or more line scans, and correct the aberration. Thereby, even when the light source is speeded up, it becomes possible to correct the aberration with high accuracy without being affected by the movement of the eyeball or the like.

[0355] The configurations described above are merely examples for preferably implementing the present invention. Therefore, any modifications (omissions, substitutions, additions, etc.) within the scope of the gist of the present invention can be appropriately made. The applicable configurations are selected, for example, according to the purpose. Further, depending on the applicable configurations, effects obvious to those skilled in the art and the effects described in this specification can be obtained.

Description of Reference Numerals

[0356] 1 Ophthalmic device 3 Display device 41 Optical path length changing unit 45 OCT focusing lens 47 VCC lens 47A VCC driving unit 100 OCT unit 103, 118 Polarization controller 114 Corner cube 114A Reference Drive 200 Calculation and Control Unit 210 Control Unit 211 Main control unit 211A Optical scanner control unit 211B Correction control unit 211C Display control unit 212 Storage section 220 Image forming unit 230 Data Processing Unit 231 Analysis Department 231A Image division section 231B Image Evaluation Unit 240A display section E. Examined eye LC interference light LR reference light LS measurement light

Claims

1. an interference optical system including an astigmatism correction optical member and an optical scanner, which splits light from a light source into measurement light and reference light, irradiates the measurement light onto the subject's eye via the astigmatism correction optical member and the optical scanner, and detects interference light between return light of the measurement light from the subject's eye and the reference light; an optical scanner control unit that controls the optical scanner to deflect the measurement light according to a first scan pattern or a second scan pattern different from the first scan pattern; a correction control unit that executes correction control to control the astigmatism correction optical member so as to correct astigmatism based on a detection result of the interference light obtained by the interference optical system by deflecting the measurement light according to the first scan pattern using the optical scanner control unit; and an image forming unit that forms an image of the subject's eye based on a detection result of the interference light obtained by the interference optical system by deflecting the measurement light according to the second scan pattern using the optical scanner control unit after the correction control is performed; an analysis unit that analyzes each of a plurality of divided images obtained by dividing the image in a direction intersecting the A-scan direction; Including, The correction control unit controls the astigmatism correction optical element based on a plurality of analysis results for the plurality of divided images.

2. the analysis unit calculates an evaluation value corresponding to the analysis result for each divided image; The correction control unit controls the astigmatism correction optical member based on a statistical value of a plurality of evaluation values ​​for the plurality of divided images.

2. An ophthalmic apparatus according to claim 1.

3. the interference optical system includes a focal position changing member that is disposed in an optical path of the measurement light and that can change a focal position of the measurement light, The correction control unit controls the focusing position changing member based on a detection result of the interference light obtained by the interference optical system by deflecting the measurement light according to the first scan pattern using the optical scanner control unit.

3. An ophthalmic apparatus according to claim 1 or 2.

4. the interference optical system includes an optical path length changing member that is disposed in an optical path of the measurement light or an optical path of the reference light and changes an optical path length difference between the measurement light and the reference light, The correction control unit controls the optical path length changing member based on a detection result of the interference light obtained by the interference optical system by deflecting the measurement light according to the first scan pattern using the optical scanner control unit.

4. The ophthalmic apparatus according to claim 1, wherein the ophthalmic apparatus is a microscope.

5. the interference optical system includes a polarization state changing member that is disposed in an optical path of the measurement light or an optical path of the reference light and changes a polarization state of the measurement light or a polarization state of the reference light, The correction control unit controls the polarization state changing member based on a detection result of the interference light obtained by the interference optical system by deflecting the measurement light according to the first scan pattern using the optical scanner control unit.

5. The ophthalmic apparatus according to claim 1, wherein the ophthalmic apparatus is a microscope.

6. The astigmatism correction optical element is capable of changing the cylindrical power and the cylindrical axis angle.

6. The ophthalmic apparatus according to claim 1, wherein the ophthalmic apparatus is a microscope.

7. The astigmatism correction optical member includes a variable cross cylinder lens.

7. An ophthalmic apparatus according to claim 6.

8. The first scan pattern is a scan pattern in which the measurement light is deflected in horizontal and vertical directions on a plane perpendicular to the optical axis of the interference optical system. The ophthalmic apparatus according to any one of claims 1 to 7.

9. The first scan pattern is a scan pattern in which the movement locus of the irradiation position of the measurement light in the measurement region is circular.

9. An ophthalmic apparatus according to claim 8.

10. A control method for an ophthalmic apparatus including an interference optical system that includes an astigmatism correction optical element and an optical scanner, splitting light from a light source into measurement light and reference light, irradiating a subject's eye with the measurement light via the astigmatism correction optical element and the optical scanner, and detecting interference light between return light of the measurement light from the subject's eye and the reference light, an optical scanner control step of controlling the optical scanner to deflect the measurement light according to a first scan pattern or a second scan pattern different from the first scan pattern; a correction control step of executing correction control to control the astigmatism correction optical member so as to correct astigmatism based on a detection result of the interference light obtained by the interference optical system by irradiating the test eye with the measurement light deflected according to the first scan pattern in the optical scanner control step; an image forming step of forming an image of the eye to be examined based on a detection result of the interference light obtained by deflecting the measurement light according to the second scan pattern in the optical scanner control step after the correction control is performed; an analysis step of analyzing each of a plurality of divided images obtained by dividing the image in a direction intersecting the A-scan direction and analyzing a detection result of the interference light; Including, The method for controlling an ophthalmic apparatus includes controlling the astigmatism correction optical element based on a plurality of analysis results corresponding to the plurality of divided images in the correction control step.

11. the analyzing step calculates an evaluation value corresponding to the analysis result for each divided image; The correction control step controls the astigmatism correction optical member based on a statistical value of the evaluation values ​​for the plurality of divided images. The method for controlling an ophthalmic apparatus according to claim 10.

12. the interference optical system includes a focal position changing member that is disposed in an optical path of the measurement light and that can change a focal position of the measurement light, The correction control step controls the focusing position changing member based on a detection result of the interference light obtained by the interference optical system by deflecting the measurement light according to the first scan pattern in the optical scanner control step.

12. The method for controlling an ophthalmic apparatus according to claim 10 or 11.

13. the interference optical system includes an optical path length changing member that is disposed in an optical path of the measurement light or an optical path of the reference light and changes an optical path length difference between the measurement light and the reference light, The correction control step controls the optical path length changing member based on a detection result of the interference light obtained by the interference optical system by deflecting the measurement light according to the first scan pattern in the optical scanner control step. The method for controlling an ophthalmic apparatus according to any one of claims 10 to 12.

14. the interference optical system includes a polarization state changing member that is disposed in an optical path of the measurement light or an optical path of the reference light and changes a polarization state of the measurement light or a polarization state of the reference light, The correction control step controls the polarization state changing member based on a detection result of the interference light obtained by the interference optical system by deflecting the measurement light according to the first scan pattern in the optical scanner control step. The method for controlling an ophthalmic apparatus according to any one of claims 10 to 13.

15. The astigmatism correction optical element is capable of changing the cylindrical power and the cylindrical axis angle. The method for controlling an ophthalmic apparatus according to any one of claims 10 to 14.

16. The astigmatism correction optical member includes a variable cross cylinder lens. The method for controlling an ophthalmic apparatus according to claim 15.

17. The first scan pattern is a scan pattern in which the measurement light is deflected in horizontal and vertical directions on a plane perpendicular to the optical axis of the interference optical system. The method for controlling an ophthalmic apparatus according to any one of claims 10 to 16.

18. The first scan pattern is a scan pattern in which the movement locus of the irradiation position of the measurement light in the measurement region is circular. The method for controlling an ophthalmic apparatus according to claim 17.

19. A program causing a computer to execute each step of the method for controlling an ophthalmic apparatus according to any one of claims 10 to 18.

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