Ophthalmic device, method for controlling ophthalmic device, and program

Abstract

To provide a novel technique for speedily and accurately identifying a depth position of a desired layer area in a subject eye.SOLUTION: An ophthalmologic apparatus comprises a layer area identifying unit and a layer area position calculation unit. The layer area identifying unit identifies a first depth position equivalent to a first layer area in an eyeground of a subject eye, on the basis of a detection result of interference light obtained by executing OCT scanning on the eyeground. The layer area position calculation unit adds a predetermined offset value to the first depth position and calculates a second depth position equivalent to a second layer area in the eyeground.SELECTED DRAWING: Figure 5

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] Axial length is measured not only to select the power of an intraocular lens (IOL) before cataract surgery, but also to confirm axial refractive error and measure eye shape.

[0003] Devices capable of measuring axial length include ultrasonic axial length measurement devices that measure axial length by contacting an ultrasonic probe with the cornea, and optical axial length measurement devices that perform optical coherence tomography on the test eye to optically measure axial length in a non-contact manner.

[0004] Generally, the axial length is measured by an ultrasonic axial length measuring device, but the measurement by the ultrasonic axial length measuring device requires skilled technique and the administration of anesthesia to the subject's eye, which places a heavy burden on the subject.

[0005] In contrast, measurements using optical axial length measuring devices do not require skilled techniques and can be performed without contact, significantly reducing the burden on the subject. However, measurements cannot be performed on eyes with cataracts, making it difficult to obtain reliable measurement results.

[0006] For example, Patent Document 1 discloses an axial length measuring device that includes an ultrasonic axial length measuring means that measures the axial length ultrasonically, and a non-contact axial length measuring means that measures the axial length optically without contact.

[0007] For example, Patent Document 2 discloses a method for measuring the axial length by identifying the position of the corneal apex and the position of the retinal pigment epithelium layer from an intensity profile in the A-scan direction obtained by performing optical coherence tomography on the test eye.

[0008] For example, Non-Patent Document 1 discloses a method for converting an optical path length corresponding to an axial length obtained by optical coherence tomography using near-infrared light of 780 nanometers (nm) as the measurement light into an axial length (physical length) measured using an ultrasonic axial length measurement device. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2008-161218 A [Patent Document 2] Special Publication No. 2014-500096 [Non-patent literature]

[0010] [Non-Patent Document 1] Suheimat M, Verkicharla PK, Mallen EAH, Rozema J, Atchison DA, “Refractive indices used by the Haag-Streit Lenstar to calculate axial biometric dimensions”, Ophthalmic & Physiological Optics 2015, 35:90-96.doi:10.1111 / opo.12182 Summary of the Invention [Problem to be solved by the invention]

[0011] Axial length is the distance from the corneal apex to the retinal pigment epithelium (RPE) layer. However, in the intensity profile of the interference signal obtained by performing optical coherence tomography, the peak corresponding to the RPE layer may be buried in peaks corresponding to layer regions such as the inner segment-outer segment junction (IS / OS line) and Bruch membrane. In such cases, it may take time to identify the peak corresponding to the RPE layer, or the peak corresponding to the RPE layer may fail to be identified or may be erroneously detected. As a result, the reliability of the axial length measurement results is reduced.

[0012] Therefore, it is required to quickly and accurately identify the depth position of a desired layer region in the subject's eye.

[0013] The present invention has been made in consideration of the above circumstances, and one of its objectives is to provide a new technology for quickly and accurately identifying the depth position of a desired layer region in a test eye. [Means for solving the problem]

[0014] A first aspect of some embodiments is an ophthalmologic device that includes a layer region identification unit that identifies a first depth position corresponding to a first layer region in the fundus based on detection results of interference light obtained by performing an OCT scan on the fundus of a test eye, and a layer region position calculation unit that adds a predetermined offset value to the first depth position to calculate a second depth position corresponding to a second layer region in the fundus.

[0015] In a second aspect of some embodiments, in the first aspect, the first layer region is an IS / OS line and the second layer region is a retinal pigment epithelium layer.

[0016] In a third aspect of some embodiments, in the first or second aspect, the layer region position calculation unit adds a different offset value to the first depth position depending on the subject's eye.

[0017] In a fourth aspect of some embodiments, in the second or third aspect, the layer region specifying unit specifies the first depth position and a third depth position corresponding to the corneal apex based on a detection result of the interference light. The ophthalmic apparatus includes an axial length calculating unit that calculates an axial length of the test eye based on the third depth position and the second depth position.

[0018] In a fifth aspect of some embodiments, in the fourth aspect, the OCT scan is performed by irradiating the test eye with measurement light having a first wavelength as a measurement wavelength, and the ophthalmic apparatus includes a wavelength correction unit that performs wavelength correction on the axial length calculated by the axial length calculation unit to correct the axial length to a second wavelength different from the first wavelength.

[0019] A sixth aspect of some embodiments is an ophthalmic device including an axial length calculation unit that calculates an axial length based on a detection result of interference light obtained by performing an OCT scan on a test eye using measurement light having a first wavelength as a measurement wavelength, and a wavelength correction unit that performs wavelength correction on the axial length calculated by the axial length calculation unit to correct it to an axial length at a second wavelength different from the first wavelength.

[0020] In a seventh aspect of some embodiments, in the fifth or sixth aspect, the wavelength correction unit corrects the axial length at the second wavelength by multiplying the axial length calculated by the axial length calculation unit by a ratio of the refractive index of the human eye at the first wavelength to the refractive index of the human eye at the second wavelength.

[0021] In an eighth aspect of some embodiments, in any one of the fifth to seventh aspects, the second wavelength is 780 nm.

[0022] A ninth aspect of some embodiments, in any of the fifth to eighth aspects, includes an axial length conversion unit that converts the axial length corrected by the wavelength correction unit into an axial length obtained using an ultrasonic axial length measurement device.

[0023] In a tenth aspect of some embodiments, in the ninth aspect, the axial length conversion unit converts the optical path length as the axial length corrected by the wavelength correction unit into a physical length as the axial length obtained using the ultrasonic axial length measurement device.

[0024] An eleventh aspect of some embodiments, in any of the first to tenth aspects, includes an OCT optical system that splits light from a light source into measurement light and reference light, irradiates the measurement light onto the test eye, and detects the interference light between return light of the measurement light from the test eye and the reference light that has passed through a reference light path.

[0025] A twelfth aspect of some embodiments is a method for controlling an ophthalmic device, including a layer area identification step of identifying a first depth position corresponding to a first layer area in the fundus based on detection results of interference light obtained by performing an OCT scan on the fundus of a test eye, and a layer area position calculation step of adding a predetermined offset value to the first depth position to calculate a second depth position corresponding to a second layer area in the fundus.

[0026] In a thirteenth aspect of some embodiments, in the twelfth aspect, the first layer region is an IS / OS line and the second layer region is a retinal pigment epithelium layer.

[0027] In a fourteenth aspect of some embodiments, in the twelfth or thirteenth aspect, the layer region identifying step identifies the first depth position and a third depth position corresponding to the corneal apex based on a detection result of the interference light. The control method for an ophthalmologic apparatus includes a step of calculating an axial length of the subject's eye based on the third depth position and the second depth position.

[0028] In a fifteenth aspect of some embodiments, in the fourteenth aspect, the OCT scan is performed by irradiating the test eye with measurement light having a first wavelength as a measurement wavelength. The control method for an ophthalmic apparatus includes a wavelength correction step of correcting the axial length calculated in the axial length calculation step to a wavelength at a second wavelength different from the first wavelength.

[0029] A sixteenth aspect of some embodiments is a method for controlling an ophthalmic device, comprising: an axial length calculation step of calculating an axial length based on a detection result of interference light obtained by performing an OCT scan on a test eye using measurement light having a first wavelength as a measurement wavelength; and a wavelength correction step of correcting the axial length calculated in the axial length calculation step to a wavelength at a second wavelength different from the first wavelength.

[0030] A seventeenth aspect of some embodiments, in the fifteenth or sixteenth aspect, includes an axial length conversion step of converting the axial length corrected in the wavelength correction step into an axial length obtained using an ultrasonic axial length measurement device.

[0031] An eighteenth aspect of some embodiments is a program for causing a computer to execute each step of the control method for an ophthalmic apparatus according to any one of the twelfth to seventeenth aspects.

[0032] The configurations according to the above-mentioned multiple claims can be combined in any manner. Effect of the Invention

[0033] According to the present invention, it is possible to provide a new technique for quickly and accurately identifying the depth position of a desired layer region in a subject's eye. [Brief description of the drawings]

[0034] [Figure 1] 1 is a schematic diagram illustrating an example of the configuration of an optical system of an ophthalmic apparatus according to an embodiment. [Diagram 2] 1 is a schematic diagram illustrating an example of the configuration of an optical system of an ophthalmic apparatus according to an embodiment. [Diagram 3] 2 is a schematic diagram illustrating an example of the configuration of a processing system of an ophthalmic apparatus according to an embodiment. FIG. [Figure 4] 2 is a schematic diagram illustrating an example of the configuration of a processing system of an ophthalmic apparatus according to an embodiment. FIG. [Diagram 5]2 is a schematic diagram illustrating an example of the configuration of a processing system of an ophthalmic apparatus according to an embodiment. FIG. [Figure 6] 5A and 5B are schematic diagrams for explaining the operation of the ophthalmologic apparatus according to the embodiment. [Figure 7] 5A and 5B are schematic diagrams for explaining the operation of the ophthalmologic apparatus according to the embodiment. [Figure 8] 5 is a schematic diagram showing a flow of an example of an operation of the ophthalmologic apparatus according to the embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] 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 drawings. Note that the contents of documents cited in this specification and any publicly known techniques may be incorporated in the following embodiments.

[0036] The ophthalmologic apparatus according to the embodiment specifies a depth position corresponding to a first layer region of the fundus based on a detection result of interference light obtained by executing an OCT scan on the subject's eye, and calculates a depth position corresponding to a second layer region of the fundus by adding a predetermined offset value to the specified depth position. For example, the first layer region is the IS / OS line, and the second layer region is the RPE layer.

[0037] This makes it possible to accurately identify the representative position on the fundus (retina) side in a short time without failing to identify the representative position on the fundus side. As a result, it is possible to improve the measurement accuracy of the intraocular distance (e.g., axial length) of the subject's eye identified using the representative position on the fundus side.

[0038] In addition, the ophthalmologic apparatus according to the embodiment can perform wavelength correction, or wavelength correction and conversion using a predetermined conversion formula, on intraocular distances such as axial length obtained based on the detection result of interference light obtained by executing an OCT scan on the subject's eye. This makes it possible to compare with the measurement results of other axial length measuring devices capable of measuring axial length with measurement light of different wavelengths and the measurement results of ultrasonic axial length measuring devices with high accuracy.

[0039] The control method of the 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 processor (computer) to execute each step of the control method of the ophthalmic apparatus. The recording medium according to the embodiment is a computer-readable non-transitory recording medium (storage medium) on which the program according to the embodiment is recorded.

[0040] In this specification, the term "processor" refers to a circuit such as a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), a field programmable gate array (FPGA)), etc. The processor realizes the functions according to the embodiment by, for example, reading and executing a program stored in a memory circuit or a storage device.

[0041] Hereinafter, a case will be described in which the ophthalmic apparatus according to the embodiment includes a measurement optical system including an OCT optical system that performs OCT on the subject's eye, but the configuration of the ophthalmic apparatus according to the embodiment is not limited to this. For example, the ophthalmic apparatus according to the embodiment may be configured to obtain a detection result of interference light from an external OCT device.

[0042] An ophthalmic apparatus according to some embodiments has not only a function of an OCT apparatus for performing OCT, but also at least one function of a fundus camera, a scanning laser ophthalmoscope, a slit lamp microscope, and a surgical microscope. Furthermore, an ophthalmic apparatus according to some embodiments has a function of measuring optical characteristics of a subject's eye. Ophthalmic apparatuses having a function of measuring optical characteristics of a subject's eye include a tonometer, a wavefront analyzer, a specular microscope, and a perimeter. An ophthalmic apparatus according to some embodiments has a function of a laser treatment apparatus used for laser treatment.

[0043] In the following, the embodiment will be described in detail with particular reference to a case where a spectral domain type OCT technique is used in measurements using OCT, etc. However, the configuration according to the embodiment can also be applied to an ophthalmic apparatus using another type of OCT (for example, a swept source type).

[0044] <Optical system configuration> 1 and 2 show an example of the configuration of an optical system of an ophthalmic apparatus according to an embodiment. Fig. 1 shows an example of the overall configuration of an optical system of an ophthalmic apparatus 1000 according to an embodiment. Fig. 2 shows an example of the configuration of the optical system of an OCT unit 100 in Fig. 1.

[0045] The ophthalmic apparatus 1000 according to the embodiment includes an optical system for observing the subject's eye E, an optical system for inspecting the subject's eye E, and a dichroic mirror for wavelength separation of the optical paths of these optical systems. An anterior eye observation system 5 is provided as the optical system for observing the subject's eye E. An OCT optical system and a refraction measurement optical system (refractive power measurement optical system) are provided as the optical system for inspecting the subject's eye E.

[0046] The ophthalmic apparatus 1000 includes an alignment system 1, a keratometry system 3, a fixation projection system 4, an anterior segment observation system 5, a reflex measurement projection system 6, a reflex measurement light receiving system 7, and an OCT optical system 8. In the following, for example, the anterior segment observation system 5 uses light of 940 nm to 1000 nm, the reflex measurement optical system (reflex measurement projection system 6, reflex measurement light receiving system 7) uses light of 850 nm to 880 nm, and the fixation projection system 4 uses light of 400 nm to 700 nm. In addition, the OCT optical system 8 uses light of 840 nm. In other words, the OCT optical system 8 executes OCT measurement (OCT scan) with a measurement wavelength of 840 nm.

[0047] (Alignment system 1) The alignment system 1 is used for Z alignment and XY alignment of the optical system with respect to the subject's eye E. The Z alignment is alignment in the Z direction (front-back direction, working distance direction) parallel to the optical axis of the anterior segment observation system 5 (e.g., the objective lens 51). The XY alignment is alignment in directions perpendicular to this optical axis (left-right direction (X direction), up-down direction (Y direction)).

[0048] The alignment system 1 includes two or more anterior eye cameras 14. The two or more anterior eye cameras 14 capture images of the anterior eye of the subject's eye E from different directions substantially simultaneously, and output the two or more captured images (anterior eye images) to a processing unit 9 described below. The processing unit 9 analyzes the two or more captured images from the two or more anterior eye cameras 14 to specify a three-dimensional position of the subject's eye E (specifically, a characteristic portion of the subject's eye E), and performs alignment of the optical system with respect to the subject's eye E (characteristic portion) in the XY and Z directions based on the specified three-dimensional position.

[0049] In the following, the alignment system 1 includes two anterior eye cameras 14. However, the alignment system 1 may include three or more anterior eye cameras 14. Furthermore, the function of one of the two anterior eye cameras 14 may be realized by an imaging element 59 included in the anterior eye observation system 5 described later.

[0050] (Anterior segment observation system 5) The anterior eye observation system 5 captures a moving image of the anterior eye of the subject's eye E. In the optical system via the anterior eye observation system 5, the imaging surface of the imaging element 59 is disposed at a pupil conjugate position (a position optically approximately conjugate with the pupil of the subject's eye E). The anterior eye illumination light source 50 irradiates the anterior eye of the subject's eye E with illumination light (e.g., infrared light). The light reflected by the anterior eye of the subject's eye E passes through the objective lens 51, transmits through the dichroic mirror 52, passes through a hole formed in the aperture (telecentric aperture) 53, passes through the relay lenses 55 and 56, and transmits through the dichroic mirror 76. The dichroic mirror 52 combines (separates) the optical path of the reflex measurement optical system and the optical path of the anterior eye observation system 5. The dichroic mirror 52 is disposed such that the optical path combining surface that combines these optical paths is inclined with respect to the optical axis of the objective lens 51. The light transmitted through the dichroic mirror 76 is focused on the imaging surface of an imaging element 59 (area sensor) by an imaging lens 58. The imaging element 59 captures images and outputs signals at a predetermined rate. The output (video signal) of the imaging element 59 is input to a processing unit 9 described below. The processing unit 9 displays an anterior eye image E' based on this video signal on a display screen 10a of a display unit 10 described below. The anterior eye image E' is, for example, an infrared moving image.

[0051] (Kerato measurement system 3) The kerato measurement system 3 projects a ring-shaped light beam (infrared light) onto the cornea Cr of the subject's eye E to measure the shape of the cornea Cr. The kerato plate 31 is disposed between the objective lens 51 and the subject's eye E. The kerato plate 31 is provided on the rear side (objective lens 51 side) of the kerato plate 31 with a kerato ring light source 32. The kerato plate 31 is formed with a kerato pattern (transmitting portion) that transmits light from the kerato ring light source 32 along a circumference centered on the optical axis of the objective lens 51. The kerato pattern may be formed in an arc shape (part of the circumference) centered on the optical axis of the objective lens 51. By illuminating the kerato plate 31 with light from the kerato ring light source 32, a ring-shaped light beam (arc-shaped or circumferential measurement pattern) is projected onto the cornea Cr of the subject's eye E. The reflected light (keratinization image) from the cornea Cr of the subject's eye E is detected together with the anterior eye image E' by the imaging element 59. The processing unit 9 performs a known calculation based on this keratinization image to calculate corneal shape parameters that represent the shape of the cornea Cr.

[0052] (Reflective measurement projection system 6, Reflective measurement receiving system 7) The refraction measurement optical system includes a refraction measurement projection system 6 and a refraction measurement light receiving system 7 used for refractive power measurement. The refraction measurement projection system 6 projects a light beam (e.g., a ring-shaped light beam) (infrared light) for refractive power measurement onto the fundus Ef. The refraction measurement light receiving system 7 receives the return light of this light beam from the subject's eye E. The refraction measurement projection system 6 is provided on an optical path branched by an aperture prism 65 provided on the optical path of the refraction measurement light receiving system 7. The hole formed in the aperture prism 65 is positioned at the pupil conjugate position. In the optical system passing through the refraction measurement light receiving system 7, the imaging surface of the imaging element 59 is positioned at the fundus conjugate position (a position optically approximately conjugate with the fundus Ef of the subject's eye E).

[0053] In some embodiments, the reflex measurement light source 61 is a superluminescent diode (SLD) light source, which is a high-brightness light source. The reflex measurement light source 61 is movable in the optical axis direction. The reflex measurement light source 61 is disposed at a fundus conjugate position. The light output from the reflex measurement light source 61 passes through a relay lens 62 and enters a conical surface of a conical prism 63. The light that enters the conical surface is deflected and exits from the bottom surface of the conical prism 63. The light that exits from the bottom surface of the conical prism 63 passes through a light-transmitting portion formed in a ring shape in the ring aperture 64. The light (ring-shaped light beam) that passes through the light-transmitting portion of the ring aperture 64 is reflected by a reflecting surface formed around the hole of the hole prism 65, passes through the rotary prism 66, and is reflected by the dichroic mirror 67. The light reflected by the dichroic mirror 67 is reflected by the dichroic mirror 52, passes through the objective lens 51, and is projected onto the subject's eye E. The rotary prism 66 is used to average the light intensity distribution of the ring-shaped light beam on the blood vessels or diseased area of ​​the fundus Ef and to reduce speckle noise caused by the light source.

[0054] The return light of the ring-shaped light beam projected on the fundus Ef passes through the objective lens 51 and is reflected by the dichroic mirror 52 and the dichroic mirror 67. The return light reflected by the dichroic mirror 67 passes through the rotary prism 66, passes through the hole of the aperture prism 65, passes through the relay lens 71, is reflected by the reflecting mirror 72, and passes through the relay lens 73 and the focusing lens 74. The focusing lens 74 is movable along the optical axis of the reflector measurement light receiving system 7. The light passing through the focusing lens 74 is reflected by the reflecting mirror 75, is reflected by the dichroic mirror 76, and is imaged on the imaging surface of the imaging element 59 by the imaging lens 58. The processing unit 9 calculates the refractive power value of the subject's eye E by performing a known calculation based on the output from the imaging element 59. For example, the refractive power value includes a spherical power, a cylindrical power and an astigmatism axis angle, or an equivalent spherical power.

[0055] (Fixation projection system 4) The OCT optical system 8 described below is provided on an optical path separated by wavelength from the optical path of the reflex measurement optical system by the dichroic mirror 67. The fixation projection system 4 is provided on an optical path branched off from the optical path of the OCT optical system 8 by the dichroic mirror 83.

[0056] The fixation projection system 4 presents a fixation target to the subject's eye E. A fixation unit 40 is disposed in the optical path of the fixation projection system 4. The fixation unit 40 is movable along the optical path of the fixation projection system 4 under the control of a processing unit 9, which will be described later. The fixation unit 40 includes a liquid crystal panel 41. A relay lens 42 is disposed between the dichroic mirror 83 and the fixation unit 40.

[0057] The liquid crystal panel 41, controlled by the processing unit 9, displays a pattern representing a fixation target. By changing the display position of the pattern on the screen of the liquid crystal panel 41, the fixation position of the subject's eye E can be changed. The fixation positions of the subject's eye E include a position for acquiring an image centered on the macular part of the fundus Ef, a position for acquiring an image centered on the optic disc, and a position for acquiring an image centered on the center of the fundus between the macular part and the optic disc. The display position of the pattern representing the fixation target can be changed arbitrarily.

[0058] Light from the liquid crystal panel 41 passes through the relay lens 42, transmits through the dichroic mirror 83, passes through the relay lens 82, is reflected by the reflecting mirror 81, transmits through the dichroic mirror 67, and is reflected by the dichroic mirror 52. The light reflected by the dichroic mirror 52 passes through the objective lens 51 and is projected onto the fundus Ef. In some embodiments, each of the liquid crystal panel 41 and the relay lens 42 is independently movable in the optical axis direction.

[0059] (OCT optical system 8) The OCT optical system 8 is an optical system for performing OCT measurement. Based on the result of a reflex measurement performed before the OCT measurement, the position of the focusing lens 87 is adjusted so that the end face of the optical fiber f1 is conjugate with the OCT measurement site and the optical system. The OCT measurement site may be any site of the subject's eye E, such as the fundus Ef or the anterior segment.

[0060] The OCT optical system 8 is provided on an optical path that is wavelength-separated from the optical path of the reflex measurement optical system by a dichroic mirror 67. The optical path of the fixation projection system 4 is coupled to the optical path of the OCT optical system 8 by a dichroic mirror 83. This allows the optical axes of the OCT optical system 8 and the fixation projection system 4 to be coaxially coupled.

[0061] The OCT optical system 8 includes an OCT unit 100. As shown in FIG. 2, the OCT unit 100 is provided with an optical system for performing OCT measurement (OCT photography, OCT scan) on the subject's eye E. This optical system has the same configuration as a conventional spectral domain type OCT device. That is, this optical system is configured to split light (low coherence light) from a broadband light source into reference light and measurement light, cause the measurement light that has passed through the subject's eye E (OCT measurement site) to interfere with the reference light that has passed through a reference light path to generate interference light, and detect the spectral components of this interference light. This detection result (detection signal) is sent to a processing unit 9.

[0062] The light source unit 101 outputs a wideband low-coherence light L0. The low-coherence light L0 has wavelength components in the near-infrared wavelength band (approximately 800 nm to 900 nm) and has a temporal coherence length of approximately several tens of micrometers. In addition, near-infrared light having a central wavelength of approximately 1040 to 1060 nm, for example, a wavelength band that cannot be seen by the human eye, may be used as the low-coherence light L0.

[0063] Hereinafter, it is assumed that the light source unit 101 outputs low-coherence light L0 having a wavelength component of 840 nm.

[0064] The light source unit 101 includes a light output device such as a super luminescent diode (SLD), an LED, or an SOA (Semiconductor Optical Amplifier).

[0065] Low-coherence light L0 output from a light source unit 101 is guided by an optical fiber 102 to a fiber coupler 103, where it is split into a measurement light LS and a reference light LR.

[0066] The reference light LR is guided by the optical fiber 104 and reaches the attenuator (optical attenuator) 105. The attenuator 105 automatically adjusts the light amount of the reference light LR guided by the optical fiber 104 under the control of the processing unit 9 using a known technique. The reference light LR whose light amount has been adjusted by the attenuator 105 is guided by the optical fiber 104 and reaches the polarization controller (polarization adjuster) 106. The polarization controller 106 is a device that adjusts the polarization state of the reference light LR guided in the optical fiber 104, for example, by applying stress from the outside to the looped optical fiber 104. Note that the configuration of the polarization controller 106 is not limited to this, and any known technique can be used. The reference light LR whose polarization state has been adjusted by the polarization controller 106 reaches the fiber coupler 109.

[0067] The measurement light LS generated by the fiber coupler 103 is guided by the optical fiber f1 to the collimator lens 90 (FIG. 1), and is collimated into a parallel beam by the collimator lens 90. Furthermore, the measurement light LS passes through an optical path length changing unit 89, an optical scanner 88, a focusing lens 87, a relay lens 85, and a reflecting mirror 84 and reaches a dichroic mirror 83.

[0068] In some embodiments, the focusing lens 87 and the optical scanner 88 are housed in one unit that is movable in the optical axis direction. This allows the focusing lens 87 and the optical scanner 88 to move in the optical axis direction while maintaining the optical positional relationship between them. By configuring the focusing lens 87 and the optical scanner 88 to be movable as a unit in this manner, it is possible to adjust the optical system while maintaining the conjugate relationship between the optical scanner 88 and the subject's eye E. In addition, in this configuration, by changing the focal length f of the focusing lens 87, it is possible to easily change the magnification relationship between the pupil of the subject's eye E and the optical scanner 88.

[0069] In some embodiments, the focusing lens 87 and the optical scanner 88 are moved independently in the optical axis direction within the unit. In some embodiments, the focusing lens 87 and the optical scanner 88 are moved independently or integrally in the optical axis direction under control of the processing unit 9. For example, the pupil of the subject's eye E is disposed at the focal position of the objective lens 51, and the deflection surface of the optical scanner 88 is disposed at the focal position of the focusing lens 87 (when the optical scanner 88 is disposed at the focal position of the focusing lens 87, a pupil conjugate relationship is maintained, and the deflection surface of the optical scanner 88 is disposed at the pupil conjugate position).

[0070] The optical path length changer 89 changes the optical path length of the measurement light LS. By changing the optical path length of the measurement light LS, it is possible to change the difference between the optical path length of the reference light LR and the optical path length of the measurement light LS. For example, the optical path length changer 89 includes a retroreflector that is movable along the optical path of the measurement light LS and the optical path of the return light of the measurement light LS, and changes the optical path length of the measurement light LS by moving the retroreflector.

[0071] The optical scanner 88 deflects the measurement light LS one-dimensionally or two-dimensionally.

[0072] In some embodiments, the optical scanner 88 includes a first galvanometer mirror and a second galvanometer mirror. The first galvanometer mirror deflects the measurement light LS so as to scan the OCT measurement site in a horizontal direction perpendicular to the optical axis of the OCT optical system 8. 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 perpendicular to the optical axis of the OCT optical system 8. Examples of the scanning mode of the measurement light LS by such an optical scanner 88 include horizontal scan, vertical scan, cross scan, radial scan, circular scan, concentric circle scan, and spiral scan.

[0073] In some embodiments, the optical scanner 88 includes a MEMS scanner (MEMS mirror scanner) that two-dimensionally deflects the measurement light LS. The MEMS scanner deflects the measurement light LS so as to scan the OCT measurement site in horizontal and vertical directions perpendicular to the optical axis of the OCT optical system 8.

[0074] In addition, the optical scanner 88 may be configured to include a polygon mirror, a rotating mirror, a dowel prism, a double dowel prism, a rotation prism, etc., in addition to the galvanometer mirror and the MEMS scanner.

[0075] The measurement light LS that reaches the dichroic mirror 83 is reflected by the dichroic mirror 83, passes through the relay lens 82, and is reflected by the reflecting mirror 81. The measurement light LS reflected by the reflecting mirror 81 is reflected by the dichroic mirror 52, refracted by the objective lens 51, and irradiated onto the OCT measurement site. The measurement light LS is scattered (including reflected) at various depth positions of the OCT measurement site. Backscattered light of the measurement light LS by the OCT measurement site travels in the opposite direction along the same path as the outward path and is guided to the fiber coupler 103, and reaches the fiber coupler 109 via the optical fiber 108.

[0076] The fiber coupler 109 causes interference between the backscattered light of the measurement light LS and the reference light LR that has passed through the attenuator 105 and the like. The interference light LC thus generated is guided by an optical fiber 110 and emitted from an emission end 111. The interference light LC is further collimated by a collimator lens 112, dispersed (spectrally resolved) by a diffraction grating (spectroscope) 113, and collected by a zoom optical system 114 to be projected onto the light receiving surface of a CCD image sensor 115. Note that although the diffraction grating 113 shown in FIG. 2 is a transmissive type, it is also possible to use other types of dispersive elements, such as a reflective diffraction grating.

[0077] The CCD image sensor 115 is, for example, a line sensor that has two or more light receiving elements (detection elements) arranged therein, detects each spectral component of the dispersed interference light LC, and converts it into an electric charge. The CCD image sensor 115 accumulates the electric charges to generate a detection signal, and sends this to the processing unit 9.

[0078] Although a Michelson interferometer is used in this embodiment, any type of interferometer, such as a Mach-Zehnder interferometer, may be used as appropriate. Also, instead of the CCD image sensor, other types of image sensors, such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor, may be used.

[0079] 1, the optical path length of the measurement light LS is changed by the optical path length changing unit 89 to change the difference between the optical path length of the measurement light LS and the optical path length of the reference light LR, but the configuration according to the embodiment is not limited to this. For example, the optical path length of the reference light LR may be changed by a known method to change the difference between the optical path length of the measurement light LS and the optical path length of the reference light LR.

[0080] The processing unit 9 calculates a refractive power value from a measurement result obtained using the refraction measurement optical system, and based on the calculated refractive power value, moves each of the refraction measurement light source 61 and the focusing lens 74 in the optical axis direction to a position where the fundus Ef, the refraction measurement light source 61, and the image sensor 59 are conjugate with each other. In some embodiments, the processing unit 9 moves the focusing lens 87 and the optical scanner 88 in the optical axis direction in conjunction with the movement of the focusing lens 74. In some embodiments, the processing unit 9 moves the liquid crystal panel 41 (fixation unit 40) in the optical axis direction in conjunction with the movement of the refraction measurement light source 61 and the focusing lens 74.

[0081] In the above embodiments, at least one function of the focusing lenses 74, 87 may be realized by a liquid crystal lens or a liquid lens.

[0082] <Processing system configuration> The configuration of the processing system of the ophthalmic apparatus 1000 will be described. An example of the functional configuration of the processing system of the ophthalmic apparatus 1000 is shown in Figs. 3 to 5. Fig. 3 shows an example of a functional block diagram of the processing system of the ophthalmic apparatus 1000. Fig. 4 shows an example of a functional block diagram of the OCT optical system 8 in Fig. 3 which is the processing target of the processing unit 9. Fig. 5 shows an example of a functional block diagram of the data processing unit 250 in Fig. 3.

[0083] The processing unit 9 controls each unit of the ophthalmologic apparatus 1000. The processing unit 9 can also execute various types of arithmetic processing. The processing unit 9 includes a processor. The processing unit 9 realizes the functions according to the embodiment by, for example, reading and executing a program stored in a memory circuit or a storage device.

[0084] The processing unit 9 includes a control unit 210 and an arithmetic processing unit 220. The ophthalmologic apparatus 1000 also includes moving mechanisms 40D, 74D, 87D, 200, a display unit 270, an operation unit 280, and a communication unit 290.

[0085] The moving mechanism 200 is a mechanism for moving the head unit housing the optical system in the X, Y, and Z directions. For example, the moving mechanism 200 is provided with an actuator that generates a driving force for moving the head unit, and a transmission mechanism that transmits this driving force. The actuator is, for example, a pulse motor. The transmission mechanism is, for example, a combination of gears or a rack-and-pinion. The control unit 210 (main control unit 211) controls the moving mechanism 200 by sending a control signal to the actuator.

[0086] The moving mechanism 40D is a mechanism for moving the fixation unit 40 in the optical axis direction of the fixation projection system 4 (the optical axis direction of the objective lens 51). For example, like the moving mechanism 200, the moving mechanism 40D is provided with an actuator that generates a driving force for moving the fixation unit 40, and a transmission mechanism that transmits this driving force. The actuator is, for example, a pulse motor. The transmission mechanism is, for example, a combination of gears or a rack-and-pinion. The control unit 210 (main control unit 211) controls the moving mechanism 40D by sending a control signal to the actuator.

[0087] The moving mechanism 74D is a mechanism for moving the focusing lens 74 in the optical axis direction of the reflector measurement light receiving system 7. For example, similar to the moving mechanism 200, the moving mechanism 74D is provided with an actuator that generates a driving force for moving the focusing lens 74, and a transmission mechanism that transmits this driving force. The actuator is, for example, a pulse motor. The transmission mechanism is, for example, a combination of gears or a rack and pinion. The control unit 210 (main control unit 211) controls the moving mechanism 74D by sending a control signal to the actuator.

[0088] The moving mechanism 87D is a mechanism for moving the focusing lens 87 in the optical axis direction of the OCT optical system 8 (the optical axis direction of the objective lens 51). For example, similar to the moving mechanism 200, the moving mechanism 87D is provided with an actuator that generates a driving force for moving the focusing lens 87, and a transmission mechanism that transmits this driving force. The actuator is, for example, a pulse motor. The transmission mechanism is, for example, a combination of gears or a rack-and-pinion. The control unit 210 (main control unit 211) controls the moving mechanism 87D by sending a control signal to the actuator.

[0089] In some embodiments, the control of the moving mechanism 87D includes control of moving the focusing lens 87 in the optical axis direction, control of moving the focusing lens 87 to a focusing reference position corresponding to the imaging region, control of moving within a moving range (focusing range) corresponding to the imaging region, etc. For example, the main control unit 211 controls the moving mechanism 87D by sending a control signal to an actuator, and moves the focusing lens 87 in the optical axis direction.

[0090] (Control unit 210) The control unit 210 includes a processor and controls each unit of the ophthalmic apparatus. The control unit 210 includes a main control unit 211 and a storage unit 212. The storage unit 212 stores in advance computer programs for controlling the ophthalmic apparatus 1000. The computer programs include an alignment system control program, a keratoconjugation system control program, a fixation system control program, an anterior eye observation system control program, a reflex measurement projection system control program, a reflex measurement light receiving system control program, an OCT optical system control program, a calculation processing program, and a user interface program. The main control unit 211 operates according to such computer programs, and the control unit 210 executes control processing.

[0091] The main control unit 211 performs various controls of the ophthalmic apparatus as a measurement control unit.

[0092] The control of the alignment system 1 includes the control of the anterior eye camera 14 .

[0093] The control of the anterior eye cameras 14 includes adjusting the exposure, gain, and detection rate of each anterior eye camera, and controlling the synchronization of image capture by the two anterior eye cameras 14. In some embodiments, the two anterior eye cameras 14 are controlled so that the exposure conditions, gain, and detection rates of the two anterior eye cameras are substantially identical.

[0094] The control of the keratometry system 3 includes control of the keratometry light source 32 .

[0095] The control of the keratinizing light source 32 includes turning on and off the light source, adjusting the light amount, adjusting the aperture, etc. As a result, the keratinizing light source 32 is switched between on and off, and the light amount is changed. The main control unit 211 causes the calculation processing unit 220 to execute a known calculation on the keratinizing image detected by the imaging element 59. As a result, the corneal shape parameters of the subject's eye E are obtained.

[0096] The control of the fixation projection system 4 includes control of the liquid crystal panel 41 and movement control of the fixation unit 40 .

[0097] The control of the liquid crystal panel 41 includes turning on and off the display of the fixation target, switching the fixation target according to the type of examination or measurement, switching the display position of the fixation target, etc. The main controller 211 controls the moving mechanism 40D by sending a control signal to the actuator, and moves at least the liquid crystal panel 41 in the optical axis direction. Thereby, the position of the liquid crystal panel 41 is adjusted so that the liquid crystal panel 41 and the fundus Ef are optically conjugate with each other.

[0098] The control of the anterior-eye observation system 5 includes control of the anterior-eye illumination light source 50, control of the image sensor 59, and the like.

[0099] The control of the anterior-eye illumination light source 50 includes turning the light source on and off, adjusting the amount of light, and adjusting the aperture. This causes the anterior-eye illumination light source 50 to be switched on and off, and changes the amount of light. The control of the image sensor 59 includes adjusting the exposure, gain, and detection rate of the image sensor 59. The main controller 211 captures a signal detected by the image sensor 59, and causes the calculation processor 220 to execute processing such as forming an image based on the captured signal.

[0100] The control of the reflex measurement projection system 6 includes control of the reflex measurement light source 61, control of the rotary prism 66, and the like.

[0101] The control of the reflex measurement light source 61 includes turning on and off the light source, adjusting the light amount, adjusting the aperture, and the like. As a result, the reflex measurement light source 61 is switched between on and off, and the light amount is changed. For example, the reflex measurement projection system 6 includes a moving mechanism that moves the reflex measurement light source 61 in the optical axis direction. This moving mechanism is provided with an actuator that generates a driving force for moving the moving mechanism, and a transmission mechanism that transmits this driving force, similar to the moving mechanism 200. The main control unit 211 controls the moving mechanism by sending a control signal to the actuator, and moves the reflex measurement light source 61 in the optical axis direction. The control of the rotary prism 66 includes rotation control of the rotary prism 66, and the like. For example, a rotation mechanism that rotates the rotary prism 66 is provided, and the main control unit 211 rotates the rotary prism 66 by controlling this rotation mechanism.

[0102] The control of the reflex measurement light receiving system 7 includes control to move the reflex measurement light source 61 and the focusing lens 74 in the optical axis direction according to the refractive power of the test eye E, so that the reflex measurement light source 61, the fundus Ef, and the image sensor 59 are optically conjugate with each other. In this case, the main controller 211 controls the moving mechanism 74D, etc. according to the refractive power of the test eye E to position the reflex measurement light source 61, the fundus Ef, and the image sensor 59 at positions where they are approximately optically conjugate with each other.

[0103] The control of the OCT optical system 8 includes control of the optical scanner 88, control of the optical path length changing unit 89, and control of the OCT unit 100. The control of the OCT unit 100 includes control of the light source unit 101, control of the attenuator 105, control of the polarization controller 106, control of the zoom optical system 114, control of the CCD image sensor 115, and the like.

[0104] The control of the optical scanner 88 includes setting a scan mode for scanning the measurement site with a predetermined scan pattern, controlling the scan range, and controlling the scan speed. By controlling the scan range (scan start position and scan end position), it is possible to control the angle range of the deflection plane for deflecting the measurement light LS. By controlling the scan speed, it is possible to control the speed at which the angle of the deflection plane is changed. The main control unit 211 controls at least one of the scan mode, scan range, and scan speed by outputting a control signal to the optical scanner 88.

[0105] The control of the optical path length changing unit 89 includes control of the optical path length of the measurement light LS. The main control unit 211 outputs a control signal to the optical path length changing unit 89 to cause the optical path length changing unit 89 to change the optical path length of the measurement light LS.

[0106] The control of the light source unit 101 includes turning the light source on and off, adjusting the light amount, and adjusting the aperture. The control of the attenuator 105 includes adjusting the light amount of the reference light LR. The control of the polarization controller 106 includes adjusting the polarization state of the reference light LR. The control of the zoom optical system 114 includes controlling the optical magnification. The control of the CCD image sensor 115 includes adjusting the exposure, gain, and detection rate of the CCD image sensor 115. The main control unit 211 takes in a signal detected by the image sensor 115, and causes the calculation processing unit 220 to execute processing such as forming an image based on the taken-in signal.

[0107] Furthermore, the main control unit 211 performs processing for writing data to the storage unit 212 and processing for reading data from the storage unit 212 .

[0108] (Storage unit 212) The storage unit 212 stores various types of data. Examples of data stored in the storage unit 212 include objective measurement results (OCT measurement results), image data of OCT images, image data of anterior eye images, subjective test results, and subject eye information. The subject eye information includes information about the subject, such as a patient ID and name, and information about the subject eye, such as left / right eye identification information. The storage unit 212 also stores various programs and data for operating the ophthalmic apparatus.

[0109] (Calculation processing unit 220) The arithmetic processing unit 220 includes a processor and executes various arithmetic processing. A storage unit (e.g., storage unit 212) not shown in the figure stores computer programs for executing various arithmetic processing in advance. The processor operates according to the computer programs to realize the functions of each unit that executes various arithmetic processing.

[0110] 3, the arithmetic processing unit 220 includes an ocular refractive power calculation unit 230, an image forming unit 240, and a data processing unit 250. The ocular refractive power calculation unit 230 calculates the ocular refractive power of the subject's eye E. The image forming unit 240 forms an OCT image based on the detection result of the interference light LC acquired using the OCT optical system 8. The data processing unit 250 performs various data processing (image processing) and analysis processing on the measurement result (detection result of the interference light LC, etc.) acquired using the optical system provided in the ophthalmic apparatus 1000 and the OCT image formed by the image forming unit 240.

[0111] (Eye refractive power calculation unit 230) The ocular refractive power calculation unit 230 analyzes a ring image (pattern image) obtained by receiving the return light of the ring-shaped light beam (ring-shaped measurement pattern) projected on the fundus Ef by the reflex measurement projection system 6 by the imaging element 59. For example, the ocular refractive power calculation unit 230 obtains the center of gravity of the ring image from the luminance distribution in the image in which the obtained ring image is depicted, obtains the luminance distribution along a plurality of scanning directions extending radially from the center of gravity, and identifies the ring image from the luminance distribution. Next, the ocular refractive power calculation unit 230 obtains an ellipse approximation of the identified ring image, and obtains the spherical power, the cylindrical power, and the cylindrical axis angle by substituting the major axis and minor axis of the ellipse into a known formula. Alternatively, the ocular refractive power calculation unit 230 can obtain parameters of the ocular refractive power based on the deformation and displacement of the ring image relative to the reference pattern.

[0112] Moreover, the eye refractive power calculation unit 230 calculates the corneal refractive power, the degree of corneal astigmatism, and the corneal astigmatism axis angle based on the keratinizing image acquired by the anterior eye observation system 5. For example, the eye refractive power calculation unit 230 calculates the corneal curvature radius of the principal meridian and the principal meridian of the anterior cornea by analyzing the keratinizing image, and calculates the above parameters based on the corneal curvature radius.

[0113] (Image forming unit 240) The image forming unit 240 forms image data of the OCT image of the test eye E based on the detection signal of the interference light LC obtained by the CCD image sensor 115. That is, the image forming unit 240 forms image data of the test eye E based on the detection result of the interference light LC by the interference optical system. This processing includes filtering, FFT (Fast Fourier Transform), and other processing, as in conventional spectral domain type OCT. 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 in the test eye E).

[0114] To improve image quality, multiple data sets collected by repeating the same pattern scan multiple times can be superimposed (averaged).

[0115] (Data processing unit 250) The data processing unit 250 performs various data processing (image processing) and analysis processing on the OCT image formed by the image forming unit 240 or the detection signal of the interference light LC obtained by the CCD image sensor 115. For example, the data processing unit 250 executes correction processing such as brightness correction and dispersion correction of the image. In addition, the data processing unit 250 performs various image processing and analysis processing on the image (anterior eye image, etc.) obtained by using the anterior eye observation system 5.

[0116] The data processing unit 250 can perform known image processing such as an interpolation process for interpolating pixels between OCT images (tomographic images) formed by the image forming unit 240 to form image data of a three-dimensional image of the fundus Ef or the anterior segment. The image data of the three-dimensional image means image data in which the positions of pixels are defined by a three-dimensional coordinate system. The image data of the three-dimensional image includes image data consisting of three-dimensionally arranged voxels. This image data is called volume data or voxel data. When an image based on the volume data is displayed, the data processing unit 250 performs a rendering process (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. The pseudo three-dimensional image is displayed on a display device such as the display unit 270.

[0117] 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 scan lines three-dimensionally based on the positional relationship of the scan lines. In other words, stack data is image data obtained by expressing multiple tomographic images that were originally defined by individual two-dimensional coordinate systems using one three-dimensional coordinate system (i.e., embedding them in one three-dimensional space).

[0118] The data processing unit 250 can perform various renderings on the acquired three-dimensional data set (volume data, stack data, etc.) to form a B-mode image (longitudinal section image, axial section image) in an arbitrary cross section, a C-mode image (transverse section image, horizontal section image) in an arbitrary cross section, a projection image, a shadowgram, etc. An image of an arbitrary cross section such as a B-mode image or a C-mode image is formed by selecting pixels (voxels) on a specified cross section from the three-dimensional data set. A projection image is formed by projecting the three-dimensional data set in a predetermined direction (Z direction, depth direction, axial direction). A shadowgram is formed by projecting a part of the three-dimensional data set (for example, partial data corresponding to a specific layer) in a predetermined direction. An image with a viewpoint on the front side of the subject's eye, such as a C-mode image, a projection image, or a shadowgram, is called an en-face image.

[0119] The data processing unit 250 can construct a B-mode image or a front image (vessel-enhanced image, angiogram) in which retinal blood vessels and choroidal blood vessels are emphasized based on data (e.g., B-scan image data) collected in time series by OCT scanning. For example, time-series OCT data can be collected by repeatedly scanning approximately the same part of the subject's eye E.

[0120] In some embodiments, the data processor 250 compares time-series B-scan images obtained by B-scanning approximately the same region, and constructs an enhanced image in which the changed portion is emphasized by converting pixel values ​​of the changed portion of signal intensity into pixel values ​​corresponding to the changed portion. Furthermore, the data processor 250 extracts information of a predetermined thickness in a desired region from the constructed multiple enhanced images, and constructs the information as an en-face image to form an OCTA image.

[0121] Images generated by the data processing unit 250 (for example, a three-dimensional image, a B-mode image, a C-mode image, a projection image, a shadowgram, and an OCTA image) are also included in the OCT image.

[0122] The data processing unit 250 also analyzes each of the two photographed images acquired substantially simultaneously by the two anterior eye cameras 14 to identify a characteristic position corresponding to the characteristic portion of the anterior eye. The characteristic portion of the anterior eye is, for example, the pupil center (pupil gravity center). The data processing unit 250 calculates the three-dimensional position of the characteristic portion (i.e., the three-dimensional position of the subject's eye E) by applying a known trigonometric method to the positions of the two anterior eye cameras 14 and the characteristic positions corresponding to the characteristic portions in the identified two photographed images. The calculated three-dimensional position can be used to align the optical system with the subject's eye E.

[0123] Furthermore, the ophthalmic apparatus 1000 can measure intraocular distances such as the axial length of the subject's eye E by performing an OCT scan on the subject's eye E. In the embodiment, the data processing unit 250 realizes the function of an axial length calculation unit.

[0124] The data processing unit 250 is capable of calculating the distance between the position corresponding to the corneal apex and the position corresponding to the RPE layer as the axial length based on the detection results of the interference light LC obtained by performing an OCT scan.

[0125] Here, in the intensity profile of the interference signal generated by detecting the interference light LC, if the peak corresponding to the RPE layer is close to the peak corresponding to the layer region such as the IS / OS line or Bruch's membrane, and the peak level corresponding to the RPE layer is lower than the peak level corresponding to the IS / OS line, etc., the peak corresponding to the RPE layer is buried in the peak corresponding to the IS / OS line, etc. As a result, it may take time to identify the peak corresponding to the RPE layer, or the peak corresponding to the RPE layer may fail to be identified, or the peak corresponding to the RPE layer may be erroneously detected.

[0126] Therefore, first, the data processing unit 250 identifies a depth position corresponding to the IS / OS line or Bruch's membrane (first layer region) based on the detection result of the interference light LC (the intensity profile of the interference light LC). Next, the data processing unit 250 adds a predetermined offset value to the identified depth position to calculate a depth position corresponding to the RPE layer (second layer region) in the fundus. This makes it possible to identify the depth position corresponding to the RPE layer in a short time and reliably. As a result, it becomes possible to improve the reliability of intraocular distances such as axial length calculated using the identified RPE layer, compared to the case where the RPE layer is directly identified.

[0127] In addition, the data processing unit 250 identifies the distance corresponding to the axial length, which is the distance between the position corresponding to the corneal apex and the position corresponding to the RPE layer, as the optical path length OPL, and calculates the axial length (physical length) AL according to the relationship shown in equation (1).

[0128]

number

[0129] In formula (1), OPL represents the optical path length, AL represents the physical length of the axial length, and n represents the refractive index of the human eye (group index). Here, the refractive index differs for each component of the eye (cornea, lens, etc.), but n represents the refractive index when the eyeball is converted into a single component.

[0130] Here, the refractive index n has wavelength dependency. This means that the axial length calculated as the physical length changes depending on the measurement wavelength. For example, the optical path length when the axial length is measured with measurement light LS having a measurement wavelength of 840 nm is defined as OPL. 840 and the refractive index at 840 nm is n 840 Similarly, the optical path length when the axial length is measured with a measurement light LS having a measurement wavelength of 780 nm is expressed as OPL. 780 and the refractive index at 780 nm is n 780 Then, we obtain the relationship shown in equation (3).

[0131]

number

[0132] This means that the axial length measured using the measuring light LS having a measurement wavelength of 840 nm is different from the axial length measured using the measuring light LS having a measurement wavelength of 780 nm.

[0133] Therefore, in the embodiment, wavelength correction is performed on the axial length measured using measurement light LS with a measurement wavelength of 840 nm, which makes it possible to calculate the axial length at a wavelength other than 840 nm (e.g., 780 nm) (axial length measured using measurement light LS having another wavelength component).

[0134] Furthermore, strictly speaking, the measurement value of the axial length obtained by the non-contact axial length measuring device according to the embodiment is different from the measurement value of the axial length obtained by the ultrasonic axial length measuring device.

[0135] Therefore, in the embodiment, the measurement value of the axial length measured using measurement light LS having a measurement wavelength of 840 nm can be converted into the measurement value of the axial length obtained by an ultrasonic axial length measurement device.

[0136] Such a data processing unit 250 includes a layer region specifying unit 251, a layer region position calculating unit 252, an axial length calculating unit 253, a wavelength correcting unit 254, and an axial length converting unit 255, as shown in FIG.

[0137] (Layer area identification unit 251) The layer region specifying part 251 specifies a depth position corresponding to a predetermined part of the subject's eye E based on the detection result of the interference light LC acquired by the OCT unit 100. Examples of the predetermined part include a predetermined layer region in the fundus Ef, the corneal apex in the anterior segment, etc. Examples of the predetermined layer region in the fundus Ef include the IS / OS line, Bruch's membrane, etc.

[0138] In the embodiment, the layer region specifying part 251 specifies a depth position corresponding to the corneal apex in the anterior eye part (cornea Cr) and a depth position corresponding to the IS / OS line in the fundus oculi Ef.

[0139] (Layer region position calculation unit 252) The layer region position calculation unit 252 adds a predetermined offset value to the depth position identified by the layer region identification unit 251, thereby calculating a depth position corresponding to another part in the subject's eye E different from the part whose depth position is identified by the layer region identification unit 251. An example of the other part is the RPE layer.

[0140] Fig. 6 is a diagram illustrating the operation of the layer region position calculation part 252 according to the embodiment. Fig. 6 shows a schematic diagram of an example of an OCT image (tomographic image) of the fundus oculi Ef.

[0141] As described above, it is assumed that the depth position corresponding to the IS / OS line is specified by the layer region specifying unit 251. The layer region position calculating unit 252 calculates a depth position corresponding to another layer region different from the IS / OS line based on the IS / OS line by adding an offset value dt to the depth position corresponding to the IS / OS line. Therefore, the layer region position calculating unit 252 can calculate a depth position corresponding to the RPE layer by adding an offset value dt to the depth position corresponding to the IS / OS line.

[0142] Examples of the offset value dt include a constant and a variable that varies depending on the subject or the eye to be examined.

[0143] When the offset value dt is a constant, the offset value dt is determined based on normative data obtained in advance by measuring a plurality of examinee's eyes. For example, the offset value dt is determined by averaging the measured values ​​for a plurality of examinee's eyes.

[0144] When the offset value dt is a variable, the offset value dt can be determined according to information of the subject. The offset value dt can also be determined according to information of the subject's eye E. The information of the subject's eye E includes intraocular distance (e.g., the distance between predetermined layer regions in the fundus Ef). In some embodiments, the offset value dt is determined according to the distance between a depth position corresponding to the IS / OS line of the subject's eye E and a depth position corresponding to the Bruch's membrane.

[0145] (Axial length calculation unit 253) The axial length calculation unit 253 calculates, as the axial length (optical path length), the distance between the depth position (first depth position) of the layer region identified by the layer region identification unit 251 and the depth position (second depth position) of another layer region different from the layer region calculated by the layer region position calculation unit 252. When calculating the axial length as a physical length, the axial length calculation unit 253 calculates the physical length of the axial length according to formula (1).

[0146] Fig. 7 is a diagram for explaining the operation of the axial length calculation unit 253 according to the embodiment. Fig. 7 shows an example of an intensity profile of an interference signal obtained by performing an OCT scan on the anterior segment, and an example of an intensity profile of an interference signal obtained by performing an OCT scan on the fundus Ef. In Fig. 7, the same parts as those in Fig. 1 or 6 are given the same reference numerals, and the description will be omitted as appropriate.

[0147] 1 has been completed using the alignment system 1 and the moving mechanism 200 so that the optical axis of the OCT optical system 8 coincides with the center of the pupil of the eye E. The layer region identifying unit 251 searches for a peak in the intensity profile of the interference signal obtained by performing an OCT scan on the anterior segment after the alignment is completed, and identifies the position of the identified peak as the depth position za corresponding to the corneal apex.

[0148] Next, the layer region identifying unit 251 searches for a peak in the intensity profile of the interference signal obtained by performing an OCT scan on the fundus Ef after the alignment is completed, and identifies the position of the peak corresponding to the IS / OS line (or Bruch's membrane) as the depth position zf. The layer region position calculating unit 252 calculates the depth position (zf+dt) corresponding to the RPE layer by adding an offset value dt to the depth position zf corresponding to the IS / OS line.

[0149] Here, when the peak corresponding to the RPE layer in the intensity profile of the interference signal is close to the peak corresponding to other layer regions, and the peak level corresponding to the RPE layer is lower than the peak level corresponding to other layer regions, it is difficult to identify the peak corresponding to the RPE layer.In contrast, in the embodiment, the depth position corresponding to the IS / OS line (or Bruch's membrane), which is easy to identify the peak, is identified, and an offset value is added to the identified depth position.Therefore, it is possible to accurately identify the representative position of the fundus Ef side in a short time without failing to identify the representative position of the fundus Ef side.

[0150] The axial length calculation unit 253 calculates the distance between the depth position za corresponding to the corneal apex identified by the layer area identification unit 251 and the depth position (zf+dt) corresponding to the RPE layer calculated by the layer area position calculation unit 252 as the axial length AL0 (optical path length).

[0151] As described above, the representative position on the fundus Ef side is accurately identified in a short time without failing to be identified, so that the measurement accuracy of the axial length of the subject's eye E can be improved.

[0152] In some embodiments, a single OCT scan is used to obtain an intensity spectrum of the interference signal ranging from the anterior segment to the fundus Ef, and the depth position corresponding to the corneal apex and the depth position corresponding to the IS / OS line are identified from the obtained intensity spectrum.

[0153] In some embodiments, the layer region identification unit 251 identifies the depth position of a layer region of the fundus Ef other than the IS / OS line (or Bruch's membrane), and the layer region position calculation unit 252 calculates the depth position of the RPE layer by adding an offset value to the identified depth position.

[0154] (Wavelength correction section 254) The wavelength correction unit 254 performs wavelength correction on the axial length calculated by the axial length calculation unit 253 as shown in equation (4), thereby correcting the axial length to one obtained using measurement light having a measurement wavelength different from the measurement wavelength (840 nm) of the measurement light LS (e.g., 780 nm).

[0155]

number

[0156] Here, the axial length (optical path length) OPL is calculated by the axial length calculation unit 253. 840 At this time, the wavelength correction unit 254 calculates the refractive index of the human eye at 780 nm (n 780 ) versus the refractive index of the human eye at 840 nm (n 840 ) is the axial length (optical path length) OPL 840 As a result, the axial length (optical path length) OPL obtained using the measurement light having a wavelength component of 780 nm is 780 Correct to.

[0157] (Axial length conversion section 255) The axial length conversion unit 255 converts the axial length, which has been wavelength-corrected by the wavelength correction unit 254, into an axial length (physical length) obtained using an ultrasonic axial length measurement device.

[0158] For example, the axial length conversion unit 255 converts the axial length (optical path length) wavelength-corrected by the wavelength correction unit 254 into the axial length (physical length) obtained using an ultrasonic axial length measurement device according to formula (5). For example, Non-Patent Document 1 discloses formula (5) as a formula for converting the optical path length obtained by a non-contact axial length measurement device into the axial length measured using an ultrasonic axial length measurement device.

[0159]

number

[0160] Here, the axial length (optical path length) OPL 780 At this time, the axial length conversion unit 255 converts the axial length (optical path length) OPL calculated by the wavelength correction unit 254 into 780 By substituting into equation (5), the axial length (physical length) AL1 is calculated.

[0161] In some embodiments, the axial length conversion unit 255 converts the axial length (optical path length) OPL calculated by the axial length calculation unit 253 into the axial length (optical path length) OPL calculated by the axial length calculation unit 253 without performing wavelength correction according to equation (4) by the wavelength correction unit 254. 840 By directly substituting into equation (6), the axial length (physical length) AL1 is calculated.

[0162]

number

[0163] In some embodiments, the main controller 211 controls the display unit 270 described later to display on the same screen the axial length (optical path length) calculated by the axial length calculator 253 and the axial length (optical path length) corrected by the wavelength corrector 254. In some embodiments, the main controller 211 controls the display unit 270 described later to display on the same screen the axial length (physical length) obtained by converting the axial length (optical path length) calculated by the axial length calculator 253 according to formula (2), and the axial length (physical length) obtained by converting the axial length (optical path length) corrected by the wavelength corrector 254 according to formula (3).

[0164] In some embodiments, the main control unit 211 controls the display unit 270 described below to display at least two of the axial length (physical length) obtained by converting the axial length (optical path length) calculated by the axial length calculation unit 253 according to equation (2), the axial length (physical length) obtained by converting the axial length (optical path length) corrected by the wavelength correction unit 254 according to equation (3), and the axial length (physical length) obtained by the axial length conversion unit 255 on the same screen.

[0165] According to the embodiment, it becomes possible to compare with high accuracy the measurement results of other axial length measuring devices that measure axial length using measuring light of different wavelengths, and the measurement results of an ultrasonic axial length measuring device.

[0166] (Display section 270, operation section 280) The display unit 270 serves as a user interface unit and displays information under the control of the control unit 210. The display unit 270 includes the display unit 10 shown in FIG.

[0167] The operation unit 280 is used as a user interface unit to operate the ophthalmic apparatus. The operation unit 280 includes various hardware keys (joystick, button, switch, etc.) provided in the ophthalmic apparatus. The operation unit 280 may also include various software keys (buttons, icons, menus, etc.) displayed on the touch panel type display screen 10a.

[0168] At least a part of the display unit 270 and the operation unit 280 may be integrally configured. A typical example of such an integral configuration is a touch panel type display screen 10a.

[0169] (Communication unit 290) The communication unit 290 has a function for communicating with an external device (not shown). The communication unit 290 has a communication interface according to a connection form with the external device. An example of the external device is a spectacle lens measuring device for measuring optical characteristics of a lens. The spectacle lens measuring device measures the diopter of the spectacle lens worn by the subject, and inputs the measurement data to the ophthalmic device 1000. The external device may be any ophthalmic device, a device (reader) that reads information from a recording medium, or a device (writer) that writes information to a recording medium. Furthermore, the external device may be a hospital information system (HIS) server, a DICOM (Digital Imaging and COmmunication in Medicine) server, a doctor's terminal, a mobile terminal, a personal terminal, a cloud server, or the like. The communication unit 290 may be provided in the processing unit 9, for example.

[0170] The IS / OS line or Bruch's membrane is an example of a "first layer region" according to an embodiment. The RPE layer is an example of a "second layer region" according to an embodiment. 840 nm is an example of a "first wavelength" according to an embodiment. 780 nm is an example of a "second wavelength" according to an embodiment.

[0171] <Example of operation> The operation of the ophthalmologic apparatus 1000 according to the embodiment will be described.

[0172] Fig. 8 shows an example of the operation of the ophthalmic apparatus 1000. Fig. 8 shows a flow diagram of the example of the operation of the ophthalmic apparatus 1000. The storage unit 212 stores a computer program for realizing the processing shown in Fig. 8. The main control unit 211 operates according to the computer program to execute the processing shown in Fig. 8.

[0173] (S1: Alignment) With the face of the subject fixed on a face receiving portion (not shown), the examiner performs a predetermined operation on the operation portion 280, whereby the ophthalmologic apparatus 1000 performs alignment.

[0174] Specifically, the main controller 211 controls the two anterior eye cameras 14 to start photographing the anterior eye of the subject's eye E. When two photographed images (anterior eye images) are acquired by the two anterior eye cameras 14, the main controller 211 controls the data processor 250 to analyze each of the two photographed images to identify a characteristic position corresponding to the pupil center, and calculates the three-dimensional position of the pupil center (subject's eye E) by applying a known trigonometric method to the positions of the two anterior eye cameras 14 and the identified characteristic positions in the two photographed images. The main controller 211 controls the moving mechanism 200 based on the calculated three-dimensional position of the subject's eye E to perform alignment of the optical system with respect to the subject's eye E. Specifically, the main controller 211 controls the moving mechanism 200 based on the calculated three-dimensional position to align the optical axis of the OCT optical system 8 (optical axis of the objective lens 51) with the axis of the subject's eye E and to make the distance of the optical system (objective lens 51) with respect to the subject's eye E a predetermined working distance. Here, the working distance is a predetermined value also called the working distance, and means the distance between the subject's eye E and the optical system during an examination using the optical system.

[0175] In addition, when the anterior eye camera 14 captures video of the anterior eye from different directions in parallel, the main control unit 211 can perform tracking of the optical system in response to the movement of the subject eye E, for example, by performing the following processes (1) and (2). (1) The data processing unit 250 sequentially analyzes two frames obtained substantially simultaneously in moving image capture by the two anterior eye cameras 14, thereby sequentially determining the three-dimensional position of the subject's eye E. (2) The main control unit 211 sequentially controls the moving mechanism 200 based on the three-dimensional position of the subject's eye E sequentially obtained by the data processing unit 250, thereby causing the position of the optical system to follow the movement of the subject's eye E.

[0176] Furthermore, the main control unit 211 moves the reflex measurement light source 61, the focusing lens 74, and the liquid crystal panel 41 to the origin position (for example, a position corresponding to 0 D (diopter)) along their respective optical axes.

[0177] (S2: Fundus OCT scan) Next, the main controller 211 controls the OCT optical system 8 and the like to perform an OCT scan on the fundus Ef.

[0178] Specifically, the main controller 211 controls the moving mechanism 87D to move the focusing lens 87 in the optical axis direction so that the focal position of the measurement light LS is set on the fundus Ef. Next, the main controller 211 adjusts the light source unit 101, the attenuator 105, the polarization controller 106, the zoom optical system 114, the CCD image sensor 115, and the optical path length changer 89. Next, the main controller 211 causes the liquid crystal panel 41 to display a pattern showing a fixation target at a display position corresponding to a desired fixation position. This allows the subject's eye E to gaze at the desired fixation position. The main controller 211 controls the optical scanner 88 to perform a scan with the measurement light LS over a predetermined scan range on the fundus Ef. The detection result of the interference light LC obtained by scanning with the measurement light LS is sent to the image forming unit 240.

[0179] (S3: Anterior segment OCT scan) Next, the main controller 211 controls the OCT optical system 8 and the like to perform an OCT scan on the anterior segment.

[0180] Specifically, the main controller 211 controls the moving mechanism 87D to move the focusing lens 87 in the optical axis direction so that the focal position of the measurement light LS is set on the anterior segment. Next, the main controller 211 adjusts the light source unit 101, the attenuator 105, the polarization controller 106, the zoom optical system 114, the CCD image sensor 115, and the optical path length changer 89. Next, the main controller 211 causes the liquid crystal panel 41 to display a pattern indicating a fixation target at a display position corresponding to a desired fixation position. The main controller 211 controls the optical scanner 88 to perform a scan with the measurement light LS over a predetermined scan range in the anterior segment. The detection result of the interference light LC obtained by scanning the measurement light LS is sent to the image forming unit 240.

[0181] (S4: Identify IS / OS line) Next, the main control unit 211 controls the layer region identification unit 251 to analyze the detection result of the interference light LC at the fundus Ef acquired in step S2 (or the OCT image of the fundus Ef) and identify the depth position corresponding to the IS / OS line.

[0182] In addition, the main control unit 211 controls the layer region identification unit 251 to analyze the detection result of the interference light LC in the anterior segment (or the OCT image of the anterior segment) acquired in step S3, and to identify the depth position corresponding to the corneal apex.

[0183] (S5: Add offset value) Next, the main controller 211 controls the layer region position calculator 252 to add a predetermined offset value to the depth position of the IS / OS line identified in step S4, thereby identifying the depth position corresponding to the RPE layer.

[0184] (S6: Calculate the axial length) Next, the main controller 211 controls the axial length calculator 253 to calculate the distance between the depth position corresponding to the corneal apex identified in step S2 and the depth position corresponding to the RPE layer calculated in step S3 as the axial length (optical path length) OPL 840 The calculation is as follows.

[0185] (S7: Wavelength correction) Next, the main controller 211 controls the wavelength corrector 254 to correct the axial length OPL calculated in step S6. 840 By performing wavelength correction according to equation (4), the axial length (OPL) at 780 nm is calculated as 780 Correct to.

[0186] (S8: Convert axial length) Next, the main controller 211 controls the axial length converter 255 to calculate the axial length OPL corrected in step S7. 780 is substituted into equation (5) to convert it into the axial length AL1 measured using the ultrasonic axial length measuring device.

[0187] In some embodiments, the main control unit 211 causes at least two of the calculation results of steps S6 to S8 to be displayed on the same screen of the display unit 270. This makes it possible to easily compare the calculation results of steps S6 to S8.

[0188] This is the end of the operation of the ophthalmologic apparatus 1000 (END).

[0189] In the flow shown in FIG. 8, step S8 is a step of calculating the axial length OPL calculated in step S6. 840 may be converted to the axial length AL1 measured using an ultrasonic axial length measuring device by substituting into equation (6).

[0190] [Effect] An ophthalmic apparatus, a control method for the ophthalmic apparatus, and a program according to an embodiment will be described.

[0191] The ophthalmologic apparatus (1000) according to the embodiment includes a layer region identifying unit (251) and a layer region position calculating unit (252). The layer region identifying unit identifies a first depth position (zf) corresponding to a first layer region in the fundus based on a detection result of interference light obtained by performing an OCT scan on the fundus (Ef) of the subject's eye (E). The layer region position calculating unit calculates a second depth position (zf+dt) corresponding to a second layer region in the fundus by adding a predetermined offset value (dt) to the first depth position.

[0192] According to this embodiment, even if it takes a long time to identify the second layer region, or if the identification fails or is erroneously detected, for example because the intensity peak of the interference light (interference signal) corresponding to the second layer region is close to the intensity peak of the interference light corresponding to another layer region, it is possible to accurately identify the depth position of the second layer region in a short time.

[0193] In some embodiments, the first layer region is the IS / OS line and the second layer region is the retinal pigment epithelium layer.

[0194] According to this aspect, even if it takes a long time to identify the retinal pigment epithelium layer, or identification fails or is erroneously detected, it is possible to accurately identify the depth position of the retinal pigment epithelium layer in a short time.

[0195] In some embodiments, the layer region position calculation section adds a different offset value to the first depth position depending on the subject's eye.

[0196] According to this aspect, since the offset value is changed depending on the eye to be examined, it becomes possible to specify the depth position of the second layer region more accurately.

[0197] In some embodiments, the layer region specifying unit specifies the first depth position and a third depth position (za) corresponding to the corneal apex based on the detection result of the interference light. The ophthalmic apparatus includes an axial length calculating unit (253) that calculates the axial length of the subject's eye based on the third depth position and the second depth position.

[0198] According to this aspect, even if it takes a long time to identify the second layer region, or if identification fails or there is an erroneous detection, the depth position of the second layer region can be accurately identified in a short time, making it possible to calculate the axial length with higher accuracy.

[0199] In some embodiments, the OCT scan is performed by irradiating the subject's eye with measurement light (LS) having a first wavelength (840 nm) as a measurement wavelength. The ophthalmic apparatus includes a wavelength correction unit (254) that performs wavelength correction on the axial length calculated by the axial length calculation unit to correct the axial length to a second wavelength (780 nm) different from the first wavelength.

[0200] According to this aspect, it is possible to compare the measured values ​​of the axial length, regardless of the wavelength dependency of the measured values ​​of the axial length obtained at different measurement wavelengths.

[0201] The ophthalmic apparatus (1000) according to the embodiment includes an axial length calculation unit (253) and a wavelength correction unit (254). The axial length calculation unit calculates the axial length based on the detection result of interference light obtained by performing an OCT scan on the subject's eye (E) using measurement light (LS) having a measurement wavelength of a first wavelength (840 nm). The wavelength correction unit performs wavelength correction on the axial length calculated by the axial length calculation unit, thereby correcting the axial length to a second wavelength (780 nm) different from the first wavelength.

[0202] According to this aspect, it is possible to compare the measured values ​​of the axial length, regardless of the wavelength dependency of the measured values ​​of the axial length obtained at different measurement wavelengths.

[0203] In some embodiments, the wavelength correction unit is configured to correct the refractive index of the human eye at the second wavelength (n 780 ) versus the refractive index of the human eye at the first wavelength (n 840 The axial length calculated by the axial length calculation unit is multiplied by the ratio of (a) to (b) to correct the axial length to the second wavelength.

[0204] According to this aspect, it is possible to correct the axial length to that obtained at a desired measurement wavelength through simple processing.

[0205] In some embodiments, the second wavelength component is 780 nm.

[0206] According to this embodiment, it becomes possible to compare the measured value of the axial length with that obtained by a non-contact axial length measuring device using a measurement wavelength of 780 nm.

[0207] Some embodiments include an axial length conversion unit (255) that converts the axial length corrected by the wavelength correction unit into an axial length obtained using an ultrasonic axial length measurement device.

[0208] According to this aspect, it becomes possible to compare the measurement value of the axial length obtained by the ophthalmic apparatus with the measurement result of the ultrasonic axial length measuring device with high accuracy.

[0209] In some embodiments, the axial length conversion unit converts the optical path length as the axial length corrected by the wavelength correction unit into a physical length as the axial length obtained using an ultrasonic axial length measurement device.

[0210] According to this aspect, it is possible to convert the measurement of the axial length obtained using an ultrasonic axial length measuring device by simple processing.

[0211] Some embodiments include an OCT optical system (8) that splits light (L0) from a light source (light source unit 101) into measurement light (LS) and reference light (LR), irradiates the measurement light to the test eye, and detects interference light (LC) between the return light of the measurement light from the test eye and the reference light that has passed through the reference light path.

[0212] According to this aspect, it is possible to provide an ophthalmologic apparatus capable of performing OCT on the subject's eye and accurately identifying the depth position of the second layer region in the fundus in a short time.

[0213] The control method for the ophthalmologic apparatus (1000) according to the embodiment includes a layer region identifying step and a layer region position calculating step. The layer region identifying step identifies a first depth position (zf) corresponding to a first layer region in the fundus based on a detection result of interference light (LC) obtained by performing an OCT scan on the fundus (Ef) of the subject's eye (E). The layer region position calculating step calculates a second depth position (zf+dt) corresponding to a second layer region in the fundus by adding a predetermined offset value (dt) to the first depth position.

[0214] According to this embodiment, even if it takes a long time to identify the second layer region, or if the identification fails or is erroneously detected, for example because the intensity peak of the interference light (interference signal) corresponding to the second layer region is close to the intensity peak of the interference light corresponding to another layer region, it is possible to accurately identify the depth position of the second layer region in a short time.

[0215] In some embodiments, the first layer region is the IS / OS line and the second layer region is the retinal pigment epithelium layer.

[0216] According to this aspect, even if it takes a long time to identify the retinal pigment epithelium layer, or identification fails or is erroneously detected, it is possible to accurately identify the depth position of the retinal pigment epithelium layer in a short time.

[0217] In some embodiments, the layer region identifying step identifies the first depth position and a third depth position (za) corresponding to the corneal apex based on a detection result of the interference light. The control method for an ophthalmic apparatus includes an axial length calculating step of calculating an axial length of the subject's eye based on the third depth position and the second depth position.

[0218] According to this aspect, even if it takes a long time to identify the second layer region, or if identification fails or there is an erroneous detection, the depth position of the second layer region can be accurately identified in a short time, making it possible to calculate the axial length with higher accuracy.

[0219] In some embodiments, the OCT scan is performed by irradiating the subject's eye with measurement light having a first wavelength (840 nm) as a measurement wavelength. The method for controlling an ophthalmic apparatus includes a wavelength correction step of correcting the axial length calculated in the axial length calculation step to a wavelength at a second wavelength (780 nm) different from the first wavelength.

[0220] According to this aspect, it is possible to compare the measured values ​​of the axial length, regardless of the wavelength dependency of the measured values ​​of the axial length obtained at different measurement wavelengths.

[0221] The control method for the ophthalmic apparatus (1000) according to the embodiment includes an axial length calculation step and a wavelength correction step. In the axial length calculation step, the axial length is calculated based on a detection result of interference light obtained by performing an OCT scan on the subject's eye (E) using measurement light (LS) having a first wavelength (840 nm) as a measurement wavelength. In the wavelength correction step, the axial length calculated in the axial length calculation step is corrected to the axial length at a second wavelength (780 nm) different from the first wavelength by performing wavelength correction on the axial length calculated in the axial length calculation step.

[0222] According to this aspect, it is possible to compare the measured values ​​of the axial length, regardless of the wavelength dependency of the measured values ​​of the axial length obtained at different measurement wavelengths.

[0223] Some embodiments include an axial length conversion step of converting the axial length corrected in the wavelength correction step into an axial length obtained using an ultrasonic axial length measurement device.

[0224] According to this aspect, it becomes possible to compare the measurement value of the axial length obtained by the ophthalmic apparatus with the measurement result of the ultrasonic axial length measuring device with high accuracy.

[0225] A program according to the embodiment causes a computer to execute each step of any one of the above-described methods for controlling an ophthalmologic apparatus.

[0226] According to this aspect, it is possible to provide a program that can accurately identify the depth position of the second layer region in a short time even when it takes a long time to identify the second layer region, or when identification fails or erroneous detection occurs, for example, when the intensity peak of the interference light (interference signal) corresponding to the second layer region is close to the intensity peak of the interference light corresponding to another layer region.

[0227] <Other> The embodiment described above is merely one example for carrying out the present invention. Anyone who wishes to carry out the present invention may make any modifications, omissions, additions, etc. within the scope of the gist of the present invention. [Explanation of symbols]

[0228] 1 Alignment system 3 Kerato measurement system 4 Fixation projection system 5 Anterior segment observation system 6 Reflector measurement projection system 7 Reflector measurement light receiving system 8 OCT optical system 9 Processing section 51 Objective Lens 88 Optical Scanner 210 Control section 211 Main control unit 250 Data Processing Unit 251 Layer area identification part 252 Layer area position calculation unit 253 Axial length calculation section 254 Wavelength correction section 255 Axis length conversion section 1000 ophthalmology equipment

Claims

1. a layer region specifying unit that specifies a first depth position corresponding to an IS / OS line or a Bruch's membrane in the fundus based on a detection result of interference light obtained by performing an OCT scan on the fundus of the test eye; a layer region position calculation unit that calculates a second depth position corresponding to a retinal pigment epithelium layer of the fundus by adding a predetermined offset value to the first depth position; 13. An ophthalmic device comprising:

2. The layer region position calculation unit adds a different offset value to the first depth position depending on the subject's eye.

2. An ophthalmic apparatus according to claim 1.

3. the layer region specifying unit specifies the first depth position and a third depth position corresponding to a corneal apex based on a detection result of the interference light, an axial length calculation unit that calculates an axial length of the subject's eye based on the third depth position and the second depth position; 3. An ophthalmic apparatus according to claim 1 or 2.

4. The OCT scan is performed by irradiating the test eye with measurement light having a first wavelength as a measurement wavelength, a wavelength correction unit that performs wavelength correction on the axial length calculated by the axial length calculation unit to correct the axial length to a second wavelength different from the first wavelength.

4. An ophthalmic apparatus according to claim 3.

5. The wavelength correction unit corrects the axial length at the second wavelength by multiplying the axial length calculated by the axial length calculation unit by a ratio of the refractive index of the human eye at the first wavelength to the refractive index of the human eye at the second wavelength.

5. An ophthalmic apparatus according to claim 4.

6. The second wavelength is 780 nm.

6. An ophthalmic apparatus according to claim 4 or 5.

7. An axial length conversion unit converts the axial length corrected by the wavelength correction unit into an axial length obtained by using an ultrasonic axial length measurement device. The ophthalmic apparatus according to any one of claims 4 to 6.

8. The axial length conversion unit converts the optical path length as the axial length corrected by the wavelength correction unit into a physical length as the axial length obtained by using the ultrasonic axial length measurement device.

8. An ophthalmic apparatus according to claim 7.

9. The OCT optical system splits light from a light source into measurement light and reference light, irradiates the measurement light onto the subject's eye, and detects interference light between return light of the measurement light from the subject's eye and the reference light passing through a reference light path. The ophthalmic apparatus according to any one of claims 1 to 8.

10. a layer region identifying step of identifying a first depth position corresponding to the IS / OS line or Bruch's membrane in the fundus based on a detection result of interference light obtained by performing an OCT scan on the fundus of the test eye; a layer region position calculation step of calculating a second depth position corresponding to a retinal pigment epithelium layer in the fundus by adding a predetermined offset value to the first depth position; A method for controlling an ophthalmic device, comprising:

11. the layer region specifying step includes specifying the first depth position and a third depth position corresponding to a corneal apex based on a detection result of the interference light; and calculating an axial length of the subject's eye based on the third depth position and the second depth position. The method for controlling an ophthalmic apparatus according to claim 10 .

12. The OCT scan is performed by irradiating the test eye with measurement light having a first wavelength as a measurement wavelength, A wavelength correction step of performing wavelength correction on the axial length calculated in the axial length calculation step to correct the axial length to a second wavelength different from the first wavelength. The method for controlling an ophthalmic apparatus according to claim 11 .

13. The axial length corrected in the wavelength correction step is converted into an axial length obtained by using an ultrasonic axial length measuring device. The method for controlling an ophthalmic apparatus according to claim 12 .

14. A program for causing a computer to execute each step of the method for controlling an ophthalmic apparatus according to any one of claims 10 to 13.

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