JP7674555B2 - Model eye - Google Patents

Description

This invention relates to a model eye.

In the medical field, various devices are used, including inspection devices, measuring devices, and imaging devices. Medical devices are precision instruments, and to fully utilize their performance, they require adjustment and calibration based on rigorous evaluation. There are various methods for evaluating medical devices, but the most widely used method is to use a reference device. A reference device is also called a standard (or etalon).

The reference devices used in evaluating medical devices are typically models (simulators) of biological tissues or organs, and are used as phantoms for evaluating radiological diagnostic devices and model eyes for evaluating ophthalmic devices. Reference devices are designed according to the method, standards, specifications, performance, evaluation items, etc. of the medical device being evaluated.

JP 2004-357868 A JP 2013-188314 A JP 2011-053462 A

The objective of this invention is to provide a new technique for evaluating ophthalmic scanning devices that scan living eyes and collect data.

The reference device according to the exemplary embodiment is used to obtain evaluation information of a medical scanning device that scans a living body based on preset scanning conditions to collect data. The reference device has a pattern formed thereon that is designed based on at least one scanning condition.

Some exemplary aspects allow for improved evaluation of ophthalmic scanning devices using an eye model.

1 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an exemplary aspect of an embodiment. 1 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an exemplary aspect of an embodiment. 1 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an exemplary aspect of an embodiment. 1 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an exemplary aspect of an embodiment. 1 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an exemplary aspect of an embodiment. 1 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an exemplary aspect of an embodiment. 1 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an exemplary aspect of an embodiment. 1 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an exemplary aspect of an embodiment. 1 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an exemplary aspect of an embodiment. 1 is a schematic diagram illustrating an example of a configuration of a model eye for evaluating an ophthalmic apparatus according to an exemplary aspect of an embodiment. 1 is a schematic diagram illustrating an example of a configuration of a reference device for evaluating an ophthalmic apparatus according to an exemplary aspect of an embodiment. 1 is a schematic diagram illustrating an example of a configuration of a reference device for evaluating an ophthalmic apparatus according to an exemplary aspect of an embodiment. 1 is a schematic diagram illustrating an example of scanning a fiducial for evaluating an ophthalmic device according to an exemplary aspect of an embodiment. 1 is a schematic diagram illustrating an example of scanning a fiducial for evaluating an ophthalmic device according to an exemplary aspect of an embodiment. FIG. 1 is a schematic diagram illustrating an example of a luminance profile obtained in a scan of a reference for evaluating an ophthalmic device according to an exemplary aspect of an embodiment. 11 is a flowchart illustrating an example of an operation that can be performed by an ophthalmologic apparatus according to an exemplary aspect of an embodiment. 11 is a flowchart illustrating an example of an operation that can be performed by an ophthalmologic apparatus according to an exemplary aspect of an embodiment. 4 illustrates some examples of data generated by an ophthalmic device according to an exemplary aspect of the embodiment. 1 illustrates an example of visualized information generated by an ophthalmologic apparatus according to an exemplary aspect of an embodiment. 1 illustrates an example of visualized information generated by an ophthalmologic apparatus according to an exemplary aspect of an embodiment. 11 is a flowchart illustrating an example of an operation that can be performed by an ophthalmologic apparatus according to an exemplary aspect of an embodiment. 1A to 1C are diagrams for explaining an example of an operation that can be performed by an ophthalmologic apparatus according to an exemplary aspect of an embodiment. 1 illustrates an example of visualized information generated by an ophthalmologic apparatus according to an exemplary aspect of an embodiment.

Some exemplary aspects of the embodiment will be described. The exemplary aspects detailed below deal with the evaluation of an ophthalmic device that combines an optical coherence tomography (OCT) device and a fundus camera, but the device (or system) to which the evaluation according to the embodiment can be applied is not limited to this.

Some aspects may evaluate ophthalmic scanning devices that scan a living eye to collect data. Ophthalmic scanning devices include OCT devices as well as ophthalmic examination devices such as scanning laser ophthalmoscopes (SLOs) (e.g., ophthalmic imaging devices, ophthalmic measurement devices). Some aspects may also evaluate devices for biometric authentication (e.g., retinal scanners).

Additionally, some embodiments may evaluate devices in medical specialties other than ophthalmology. For example, some embodiments may evaluate devices used in radiology, dermatology, or dentistry. Specific types of devices include x-ray computed tomography (CT) scanners, ultrasound scanners, OCT scanners, laser scanners, etc.

As such, the subject to which the evaluation according to the embodiment is applied may be any medical scanning device. In general, a medical scanning device is an examination device (imaging device, measuring device, etc.) that sequentially acquires data (information) from multiple positions on a living body, and is typically configured to scan the living body and collect data based on pre-set scanning conditions.

The scan conditions may be any conditions (parameters, options, etc.) related to the scan, examples of which include the scan pattern (scan trajectory shape), scan area shape, scan dimensions (length, area, volume, depth, diameter, circumference), scan spatial interval (scan spatial density), scan time interval, scan pattern repetition time interval, etc. Note that the scan conditions are not limited to these.

The evaluation parameter according to the embodiment may be an evaluation parameter corresponding to any of the scan conditions, or may be any evaluation parameter related to any of the scan conditions. The parameter related to the scan condition may be, for example, any evaluation parameter that affects the scan condition.

At least some of the functionality of the elements disclosed herein is implemented using circuitry or processing circuitry. The circuitry or processing circuitry may be a general-purpose processor, a special-purpose processor, an integrated circuit, a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), a field programmable gate array (FPGA), a programmable logic device (PGD ... Array), conventional circuitry, and any combination thereof. A processor is considered to be a processing circuitry or circuitry, including transistors and/or other circuitry. In this disclosure, a circuitry, unit, means, or similar term is hardware that performs at least some of the disclosed functions or is hardware that is programmed to perform at least some of the disclosed functions. The hardware may be hardware disclosed herein or known hardware that is programmed and/or configured to perform at least some of the described functions. If the hardware is a processor that can be considered to be a type of circuitry, then a circuitry, unit, means, or similar term is a combination of hardware and software, and the software is used to configure the hardware and/or the processor.

An exemplary embodiment of an ophthalmic device is shown in FIG. 1. The ophthalmic device 1 in this example is a combination device of an OCT device and a fundus camera. The method of this OCT device is spectral domain OCT, but it may be swept source OCT. Spectral domain OCT is a method of splitting light from a low coherence light source into measurement light and reference light, superimposing the return light of the measurement light from the test object on the reference light to generate interference light, detecting the spectral distribution of this interference light with a spectroscope, and applying Fourier transform or the like to the detected spectral distribution to form an image. On the other hand, swept source OCT is a method of splitting light from a wavelength-variable light source into measurement light and reference light, superimposing the return light of the measurement light from the test object on the reference light to generate interference light, detecting this interference light with a photodetector such as a balanced photodiode, and applying Fourier transform or the like to the detection data collected in response to the sweeping of the wavelength and the scanning of the measurement light to form an image. In this way, spectral domain OCT is an OCT method that acquires the spectral distribution by spatial division, and swept source OCT is an OCT method that acquires the spectral distribution by time division.

In this embodiment, unless otherwise specified, no distinction is made between "image data" and "images," which are visualization information generated based on the image data. Furthermore, unless otherwise specified, no distinction is made between a part of the subject's eye (organs, tissues, etc.) and a corresponding part of the phantom (reference device, eye model, etc.). Furthermore, unless otherwise specified, no distinction is made between a part of the subject's eye and its corresponding data (images, etc.), and no distinction is made between a part of the phantom (reference device, eye model, etc.) and its corresponding data (images, etc.). The same may be true when scanning parts other than the eye (organs, tissues, etc.).

The ophthalmic device 1 includes a fundus camera unit 2, an OCT unit 100, and an arithmetic and control unit 200. The fundus camera unit 2 is provided with an optical system and mechanism for acquiring a front image of the subject's eye E, and an optical system and mechanism for applying an OCT scan to the subject's eye E. The OCT unit 100 is provided with an optical system and mechanism for performing an OCT scan. The arithmetic and control unit 200 includes one or more processors configured to perform various processes (arithmetic, control, etc.).

The ophthalmic device 1 is equipped with a lens unit 400 for switching the area to which the OCT scan is applied. The lens unit 400 can be placed between the objective lens 22 and the subject's eye E. By inserting the lens unit 400 into the optical path, the area to which the OCT scan is applied is switched from the fundus Ef to the anterior segment.

The fundus camera unit 2 is provided with an optical system for photographing the subject's eye E (fundus Ef and anterior segment). The digital images acquired are front images such as observation images and photographed images. Typically, observation images are acquired by video capture using continuous light in the near-infrared region, and photographed images are acquired as still images using flash light in the near-infrared region or visible region.

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

The light (observation illumination light) output from the observation light source 11 of the illumination optical system 10 is reflected by the concave mirror 12, passes through the condenser lens 13, and passes through the visible cut filter 14 to become near-infrared light. Furthermore, the observation illumination light is once focused near the photographing light source 15, reflected by the mirror 16, and is guided to the aperture mirror 21 via the relay lens system 17, the relay lens 18, the aperture 19, and the relay lens system 20. The observation illumination light is then reflected at the periphery (area around the hole) of the aperture mirror 21, passes through the dichroic mirror 46, and is refracted by the objective lens 22 to illuminate the subject's eye E. The return light of the observation illumination light from the subject's eye E is refracted by the objective lens 22, passes through the dichroic mirror 46, passes through the hole formed in the central area of the aperture mirror 21, passes through the dichroic mirror 55, passes through the photographing focusing lens 31, and is reflected by the mirror 32. Furthermore, this return light passes through the half mirror 33A, is reflected by the dichroic mirror 33, and is imaged on the light receiving surface of the image sensor 35 by the imaging lens 34. The image sensor 35 detects the return light at a predetermined frame rate. The focus of the photographing optical system 30 can be adjusted to match the fundus Ef or its vicinity, and can also be adjusted to match the anterior segment or its vicinity.

The light output from the imaging light source 15 (imaging illumination light) is projected onto the fundus Ef via the same path as the observation illumination light. The return light of the imaging illumination light from the subject's eye E is guided to the dichroic mirror 33 via the same path as the return light of the observation illumination light, passes through the dichroic mirror 33, is reflected by the mirror 36, and is imaged by the imaging lens 37 on the light receiving surface of the image sensor 38.

The liquid crystal display (LCD) 39 displays a fixation target (fixation target image). A part of the visible light beam output from the LCD 39 is reflected by the half mirror 33A, reflected by the mirror 32, passes through the photographing focusing lens 31 and the dichroic mirror 55, passes through the hole of the aperture mirror 21, passes through the dichroic mirror 46, is refracted by the objective lens 22, and is projected onto the fundus Ef. The fixation target is typically used to guide and fix the line of sight. The direction in which the line of sight of the subject's eye E is guided (and fixed), that is, the direction in which the subject's eye E is prompted to fixate, is called the fixation position. The fixation position can be changed by changing the display position of the fixation target image on the screen of the LCD 39. The ophthalmic device 1 may be capable of providing a graphical user interface (GUI) for changing the fixation position.

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

The alignment method applicable to the embodiment is not limited to those using such alignment indicators, but may be, for example, a method using a stereo camera, a method using Purkinje images, a method using an optical lever, or any combination thereof.

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

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

The dichroic mirror 46 combines the optical path for the fundus camera with the optical path for the OCT scan (measurement arm). The dichroic mirror 46 reflects light in the wavelength band used for the OCT scan and transmits light in the wavelength band used for the fundus camera. The measurement arm is provided with a collimator lens unit 40, a retroreflector 41, a dispersion compensation member 42, an OCT focusing lens 43, an optical scanner 44, and a relay lens 45, in that order from the OCT unit 100 side.

The retroreflector 41 can be moved along the optical path of the measurement light LS incident on it, thereby changing the length of the measurement arm. Changing the measurement arm length is used, for example, to correct the optical path length according to the axial length of the eye, or to adjust the interference state.

The dispersion compensation member 42, together with the dispersion compensation member 113 (described later) arranged in the reference arm, acts to match the dispersion characteristics of the measurement light LS and the reference light LR.

The OCT focusing lens 43 is moved along the measurement arm to adjust the focus of the measurement arm. The movement of the imaging focusing lens 31, the movement of the focus optical system 60, and the movement of the OCT focusing lens 43 can be controlled in a coordinated manner.

The optical scanner 44 is substantially disposed at a position optically conjugate with the pupil of the subject's eye E. The optical scanner 44 deflects the measurement light LS guided by the measurement arm. The optical scanner 44 is, for example, a galvano scanner capable of two-dimensional scanning. Typically, the optical scanner 44 includes a one-dimensional scanner (x-scanner) for deflecting the measurement light in the ±x direction, and a one-dimensional scanner (y-scanner) for deflecting the measurement light in the ±y direction. In this case, one of the one-dimensional scanners is disposed at a position optically conjugate with the pupil, or a position optically conjugate with the pupil is disposed between the two one-dimensional scanners.

The exemplary OCT unit 100 shown in FIG. 2 is provided with an optical system for spectral domain OCT. This optical system includes an interference optical system. This interference optical system splits light from a low-coherence light source (broadband light source) into measurement light and reference light, and generates interference light by superimposing the return light of the measurement light projected onto the subject's eye E on the reference light that has passed through the reference arm. The spectral distribution of the interference light generated by the interference optical system is detected by a spectrometer. The output (detection signal) from the spectrometer is sent to the arithmetic and control unit 200.

The light source unit 101 outputs broadband low-coherence light L0. The low-coherence light L0 includes, for example, a wavelength band in the near-infrared region (approximately 800 nm to 900 nm) and has a temporal coherence length of approximately several tens of micrometers. The low-coherence light L0 may be near-infrared light having a central wavelength of approximately 1040 to 1060 nm, for example, a wavelength band that is not visible to the human eye. The light source unit 101 includes an optical output device such as a superluminescent diode (SLD), an LED, or a semiconductor optical amplifier (SOA).

In an embodiment in which swept-source OCT is employed, the light source unit includes, for example, a near-infrared tunable laser that changes the wavelength of the emitted light at high speed.

The low-coherence light L0 output from the light source unit 101 is guided by an optical fiber 102 to a polarization controller 103, where its polarization state is adjusted. The light L0 whose polarization state has been adjusted is guided by an optical fiber 104 to a fiber coupler 105, where it is split into a measurement light LS and a reference light LR.

The reference light LR generated by the fiber coupler 105 is guided by the optical fiber 110 to the collimator 111, where it is converted into a parallel beam, and is guided to the retroreflector 114 via the optical path length correction member 112 and the dispersion compensation member 113. The optical path length correction member 112 acts to match the optical path length of the reference light LR with the optical path length of the measurement light LS. The dispersion compensation member 113, together with the dispersion compensation member 42 arranged in the measurement arm, acts to match the dispersion characteristics between the reference light LR and the measurement light LS. The retroreflector 114 is movable along the optical path of the reference light LR incident thereon, thereby changing the length of the reference arm. The change in the reference arm length is used, for example, for optical path length correction according to the axial length and for adjusting the interference state.

The reference light LR that has passed through the retroreflector 114 passes through the dispersion compensation member 113 and the optical path length correction member 112, is converted from a parallel beam to a focused beam by the collimator 116, and enters the optical fiber 117. The reference light LR that has entered the optical fiber 117 is guided to the polarization controller 118, where its polarization state is adjusted, is guided through the optical fiber 119 to the attenuator 120, where its light amount is adjusted, and is guided through the optical fiber 121 to the fiber coupler 122.

Meanwhile, the measurement light LS generated by the fiber coupler 105 is guided through the optical fiber 127 to the collimator lens unit 40, where it is converted into a parallel beam, passes through the retroreflector 41, the dispersion compensation member 42, the OCT focusing lens 43, the optical scanner 44, and the relay lens 45, is reflected by the dichroic mirror 46, is refracted by the objective lens 22, and is projected onto the subject's eye E. The measurement light LS is scattered and reflected at various depth positions in the subject's eye E. The return light of the measurement light LS from the subject's eye E travels in the opposite direction through the measurement arm, is guided to the fiber coupler 105, and reaches the fiber coupler 122 via the optical fiber 128.

The fiber coupler 122 generates interference light LC by superimposing the measurement light LS incident via the optical fiber 128 and the reference light LR incident via the optical fiber 121.

The interference light LC generated by the fiber coupler 122 is guided to the spectrometer 130 through the optical fiber 123. The spectrometer 130 includes, for example, a collimator lens that converts the incident interference light LC into a parallel beam, a diffraction grating that resolves the parallel beam of interference light LC into spectral components, and an image sensor that detects the resolved spectral components. This image sensor is, for example, a line sensor that detects multiple spectral components of the interference light LC and generates an electrical signal (detection signal). The generated detection signal is sent to the arithmetic and control unit 200.

In a mode in which swept-source OCT is employed, interference light generated by superimposing measurement light and reference light is branched at a predetermined branching ratio (e.g., 1:1) to generate a pair of interference light, and the generated pair of interference light is guided to a photodetector. The photodetector includes, for example, a balanced photodiode. The balanced photodiode includes a pair of photodetectors that respectively detect the pair of interference light, and outputs the difference between the pair of detection signals obtained by these. The photodetector sends this output (detection signal such as a difference signal) to a data acquisition system (DAQ). A clock is supplied to the data acquisition system from the light source unit. The clock is generated in the light source unit in synchronization with the output timing of each wavelength swept within a predetermined wavelength range by the wavelength-tunable light source. For example, the light source unit branches light of each output wavelength to generate two branched lights, optically delays one of the branched lights, combines the branched lights, detects the obtained combined light, and generates a clock based on the detection signal. The data acquisition system performs sampling of the detection signal (differential signal) input from the photodetector based on the clock. The data obtained from this sampling is used for processing such as image construction.

The ophthalmic device 1 shown in Figures 1 and 2 is provided with both an element for changing the measurement arm length (e.g., retroreflector 41) and an element for changing the reference arm length (e.g., retroreflector 114 or reference mirror), but in some exemplary embodiments, only one of these elements is provided. The coherence gate position is changed by changing the measurement arm length and the reference arm length relatively (i.e., by changing the optical path length difference between the measurement arm and the reference arm). The element for changing the optical path length difference is not limited to the elements disclosed in this embodiment, and may be any element (optical member, mechanism, etc.).

The arithmetic control unit 200 controls each part of the ophthalmic device 1. The arithmetic control unit 200 also performs various calculations. For example, the arithmetic control unit 200 forms a reflection intensity profile for each A-line by performing signal processing such as Fourier transform on the spectral distribution acquired by the spectroscope 130. Furthermore, the arithmetic control unit 200 forms image data by imaging the reflection intensity profile of each A-line. The calculation processing for this is similar to that of conventional spectral domain OCT.

The arithmetic control unit 200 includes, for example, a processor, a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk drive, a communication interface, and the like. Various computer programs are stored in storage devices such as the hard disk drive. The arithmetic control unit 200 may also include an operation device, an input device, a display device, and the like.

Examples of the configuration of the processing system of the ophthalmic device 1 are shown in Figures 3A to 4E. Figure 3A shows an example of the configuration of the entire processing system. The ophthalmic device 1 in Figure 3A includes a control unit 210, an image forming unit 220, and a data processing unit 230. The control unit 210, the image forming unit 220, and the data processing unit 230 are provided in, for example, the arithmetic control unit 200. Figure 3B shows an example of the configuration of the data processing unit 230. The data processing unit 230A in Figure 3B includes an evaluation unit 250 and a visualization information generation unit 270. Figures 4A to 4E show several examples of the configuration of the evaluation unit 250.

In this embodiment, the evaluation unit 250 and the visualization information generating unit 270 are provided in the ophthalmic device 1 to be evaluated. On the other hand, in some embodiments, an element corresponding to at least a part of the evaluation unit 250 and/or an element corresponding to at least a part of the visualization information generating unit 270 may be provided outside the device to be evaluated (medical scanning device, ophthalmic scanning device). For example, an element corresponding to at least a part of the evaluation unit 250 and/or an element corresponding to at least a part of the visualization information generating unit 270 may be provided in an information processing device (computer) connected to the device to be evaluated by wire or wirelessly. In addition, an element corresponding to at least a part of the evaluation unit 250 may be provided in a first information processing device connected to the device to be evaluated by wire or wirelessly, and an element corresponding to at least a part of the visualization information generating unit 270 may be provided in a second information processing device connected to the first information processing device by wire or wirelessly. Here, each of the information processing device, the first information processing device, and the second information processing device may be a single computer or two or more computers.

At least two of the configuration examples in Figures 3A to 4E can be combined. Any publicly known technology and/or equivalent technology can be combined with any one or a combination of two or more of these configuration examples. Any one or a combination of two or more of these configuration examples can be combined with equivalent technology to any of the configuration examples. This "combination" may be any modification such as addition, substitution, or omission. The same applies to components other than the processing system (any matter in this disclosure).

The control unit 210 includes a processor and controls each part of the ophthalmic device 1. The control unit 210 includes a main control unit 211 and a memory unit 212.

The main control unit 211 includes a processor and controls each element of the ophthalmic device 1 (including the elements shown in Figures 1 to 4E). The main control unit 211 is realized, for example, by the cooperation of hardware including circuits and control software.

The imaging focusing lens 31 arranged in the imaging optical path and the focus optical system 60 arranged in the illumination optical path are moved integrally or in cooperation with each other by an imaging focusing drive unit (not shown) under the control of the main control unit 211. The retroreflector 41 provided in the measurement arm is moved by a retroreflector (RR) drive unit 41A under the control of the main control unit 211. The OCT focusing lens 43 arranged in the measurement arm is moved by an OCT focusing drive unit 43A under the control of the main control unit 211. The movement of the OCT focusing lens 43 can be performed in cooperation with the movement of the imaging focusing lens 31 and the focus optical system 60. The retroreflector 114 arranged in the reference arm is moved by a retroreflector (RR) drive unit 114A under the control of the main control unit 211. Each of the mechanisms illustrated here typically includes an actuator such as a pulse motor that operates under the control of the main control unit 211. The optical scanner 44 provided on the measurement arm operates under the control of the main controller 211. Furthermore, the main controller 211 can control any element included in the ophthalmic apparatus 1, such as the polarization controller 103, the polarization controller 118, the attenuator 120, various light sources, various optical elements, various devices, and various mechanisms. The main controller 211 may also be capable of controlling any peripheral equipment (apparatus, equipment, device, etc.) connected to the ophthalmic apparatus 1, and any equipment, equipment, device, etc. accessible by the ophthalmic apparatus 1.

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

The memory unit 212 stores various types of data. Examples of data stored in the memory unit 212 include image data of OCT images, image data of fundus images, and information about the subject's eye. The information about the subject's eye includes subject information such as a patient ID and name, left/right eye identification information, and electronic medical record information.

Furthermore, the storage unit 212 can store data generated by the data processing unit 230. For example, evaluation information and/or visualization information described below are stored in the storage unit 212. The storage unit 212 can also store information related to a reference device (model eye) described below. For example, standard information described below is stored in the storage unit 212.

The user interface 240 includes a display unit 241 and an operation unit 242. The display unit 241 displays information under the operation of the main control unit 211, and includes, for example, a display device 3. The operation unit 242 includes various operation devices and input devices, generates signals corresponding to operations and inputs, and sends them to the main control unit 211. The user interface 240 may include a device such as a touch panel that integrates a display function and an operation function. An ophthalmic device according to some exemplary aspects may not include at least a part of the user interface. For example, the display device and/or the operation device may be peripheral devices of the ophthalmic device.

The image forming unit 220 forms OCT image data based on the data acquired by the spectrometer 130. The image forming unit 220 includes a processor. The image forming unit 220 is realized, for example, by the cooperation of hardware including a circuit and image forming software.

The image forming unit 220 forms cross-sectional image data based on the data acquired by the spectroscope 130. This image forming process includes signal processing such as sampling (A/D conversion), noise removal (noise reduction), filtering, and fast Fourier transform (FFT), similar to conventional spectral domain OCT.

The image data formed by the image forming unit 220 is a data set that includes a group of image data (a group of A-scan image data) formed by imaging the reflection intensity profile in multiple A-lines (scan lines along the z-direction) arranged in the area where the OCT scan was applied.

The image data formed by the image forming unit 220 is, for example, one or more B-scan image data, or stack data formed by embedding multiple B-scan image data in a single three-dimensional coordinate system. The image forming unit 220 can also perform voxelization processing on the stack data to construct volume data (voxel data). Stack data and volume data are typical examples of three-dimensional image data expressed in a three-dimensional coordinate system.

The data processing unit 230 executes various types of data processing. For example, the data processing unit 230 can apply image processing and analysis processing to OCT image data, and can apply image processing and analysis processing to observation image data or captured image data. The data processing unit 230 includes a processor. The data processing unit 230 is realized, for example, by the cooperation of hardware including circuits and data processing software.

The data processing unit 230 can process the three-dimensional image data constructed by the image forming unit 220. For example, the data processing unit 230 can construct new image data by applying rendering to the three-dimensional image data. Rendering methods include volume rendering, maximum intensity projection (MIP), minimum intensity projection (MinIP), surface rendering, and multiplanar reconstruction (MPR). The data processing unit 230 can also construct projection data by projecting the three-dimensional image data in the z direction (A-line direction, depth direction). Similarly, the data processing unit 230 can construct a shadowgram by projecting a part of the three-dimensional image data (three-dimensional partial image data) in the z direction. Here, the three-dimensional partial image data is set, for example, by applying segmentation to the three-dimensional image data. This segmentation may include, for example, image analysis (image processing) such as threshold processing and edge detection, or may include semantic segmentation using machine learning.

The data processing unit 230A shown in FIG. 3B is an example of the data processing unit 230. The data processing unit 230A includes an evaluation unit 250 and a visualization information generation unit 270. Note that some aspects of the data processing unit 230 may include only the evaluation unit 250.

The evaluation unit 250 is configured to generate evaluation information of the ophthalmic device 1. The evaluation unit 250 generates the evaluation information based on data collected by scanning a reference device (model eye) described below. More generally, some aspects of the evaluation unit 250 are configured to generate evaluation information of a device (medical scanning device, ophthalmic scanning device) that scans a living body and collects data based on preset scanning conditions, based on data collected by scanning a reference device with the device. The evaluation information is information that represents a predetermined quality of the target device, such as the quality of operation, the quality of function, the quality of control, the quality of obtained data, the quality of data processing, etc.

Some examples of the evaluation unit 250 are shown in Figures 4A to 4E. As mentioned above, the evaluation unit 250 may be a combination of any two or more of the exemplary evaluation units 250A to 250E. Below, we will first provide an overview of the evaluation units 250A to 250E, which are some examples of the evaluation unit 250, and then explain specific aspects of the evaluation of the ophthalmic device 1 that can be performed using the evaluation unit 250.

The evaluation unit 250A in FIG. 4A is configured to generate evaluation information based on the projection data of the three-dimensional image data constructed by the image forming unit 220. The evaluation unit 250A includes a projection processing unit 251 and an evaluation information generating unit 252.

The projection processing unit 251 is configured to construct projection data (two-dimensional image data) from three-dimensional image data collected by scanning the three-dimensional area of the fiducial with the ophthalmic device 1. The process of constructing projection data from three-dimensional image data (projection) includes, for example, a calculation of adding up in the z direction the values of multiple pixels contained in each A-scan image data constituting the three-dimensional image data. The projection data of the three-dimensional image data expressed in the xyz coordinate system is two-dimensional image data expressed in the xy coordinate system.

The evaluation information generation unit 252 is configured to generate evaluation information based on the projection data constructed by the projection processing unit 251.

The evaluation unit 250 (e.g., evaluation unit 250A) may be configured to generate evaluation information based on data collected by scanning a reference device with the ophthalmic device 1 and standard information of the pattern.

A predetermined pattern is formed on the reference device. The standard information of the pattern referred to by the evaluation unit 250 represents the aspect of the pattern formed on the reference device. The aspect of the pattern represented by this standard information may be any parameter related to the pattern, for example, shape, dimensions, distribution, number, spacing, etc. The shape of the pattern may be a three-dimensional shape, a two-dimensional shape, a cross-sectional shape, etc. When the pattern consists of multiple sub-patterns (basic patterns or a combination thereof), the shape of the pattern represented by the standard information may be the shape of the sub-pattern or the shape of the entire pattern. The dimensions of the pattern may be length, width, depth, diameter, area, volume, etc. When the pattern consists of multiple sub-patterns, the dimensions of the pattern represented by the standard information may be the dimensions of the sub-pattern or the dimensions of the entire pattern. The distribution of the pattern may be the distribution of the multiple sub-patterns constituting the pattern. The distribution may be, for example, density, the ratio of the dimensions of the pattern part to the dimensions of the non-pattern part, or the ratio of the dimensions of the reference device to the pattern part. The number of patterns may be the number of multiple sub-patterns constituting the pattern. The spacing of a pattern may be the distance between two adjacent sub-patterns among the multiple sub-patterns that make up the pattern. When a pattern is made up of multiple sub-patterns, the standard information of the pattern may include a statistical quantity calculated based on at least some of the multiple sub-patterns, or may be a value for each sub-pattern.

The standard information of the pattern is created in advance, for example, based on the design information of the reference device and/or the measurement data of the reference device. The design information of the reference device is information referenced to form a pattern on the reference device. The design information is created based on at least one scan condition for an OCT scan that the ophthalmic device 1 can execute. In other words, a reference device on which a pattern designed based on at least one scan condition is formed is used for the evaluation of this embodiment. On the other hand, the measurement data of the reference device is data obtained by actually measuring the reference device, and includes information about the pattern formed on the reference device. The standard information created in this manner is, for example, stored in the memory unit 212 and/or stored in a storage device or recording medium accessible to the ophthalmic device 1.

When evaluating the ophthalmic device 1, the ophthalmic device 1 can apply a predetermined pattern of scans to the reference device. This scan pattern includes a line scan, for example a raster scan. A raster scan consists of multiple line scans that are parallel to each other.

Furthermore, the evaluation unit 250 may be configured to determine the straightness (linearity, degree of linearity) of the line scan as evaluation information based on data collected by the scan applied to the reference device. The trajectory of the line scan is ideally a straight line, but there is a possibility that the trajectory of the line scan may deviate from a straight line due to errors in the configuration and control of the ophthalmic device 1. The evaluation unit 250 in this example can evaluate whether the trajectory of the line scan of the ophthalmic device 1 can be considered as a straight line, and can also evaluate the degree of deviation from a straight line.

A linear pattern is formed on the reference device used to evaluate the straightness of the line scan. This linear pattern may be, for example, a linearly formed concave portion (groove, valley) and/or a convex portion. The dimensions of the groove may be designed based on the scanning conditions of the line scan. For example, the length of the groove may be designed based on the length of the line scan, etc. The depth of the groove may be designed based on the length of the A-scan (imaging range in the depth direction, imaging range in the axial direction), etc. The width of the groove may be designed based on the beam diameter of the measurement light, the line scan interval in the raster scan, etc. Convex portions can also be designed in the same manner.

The ophthalmic device 1 applies a scan to the reference device on which such a linear pattern is formed. This scan may be at least one line scan set parallel to the linear pattern, and may typically be a raster scan. For example, the position at which the scan is applied is set so that at least a portion of one or more line scans coincides with at least a portion of the linear pattern. The evaluation unit 250 can determine the straightness of the line scan of the ophthalmic device 1 based on the data collected by this scan and the standard information of the linear pattern. Here, the standard information of the linear pattern is included in the standard information of the pattern described above.

A configuration example of the evaluation unit 250 for evaluating the straightness of a line scan is shown in FIG. 4B. The evaluation unit 250B in this example includes a projection processing unit 253, a position data generation unit 254, and a straightness calculation unit 255. In this example, the ophthalmic apparatus 1 applies a scan to a three-dimensional area (including at least a part of the linear pattern) of the reference device on which the linear pattern is formed. This scan is, for example, a raster scan.

The projection processing unit 253 is configured to construct projection data from data (three-dimensional data) collected by scanning the three-dimensional area of the reference device. The projection processing unit 253 executes processing similar to that of the projection processing unit 251 described above to construct projection data from three-dimensional image data collected by scanning the three-dimensional area of the reference device. This projection data is, for example, two-dimensional image data expressed in an xy coordinate system.

The position data generating unit 254 is configured to obtain position data of the linear pattern based on the projection data constructed by the projection processing unit 253. This position data includes position information of the image of the linear pattern depicted in the projection data (two-dimensional image data). The position data generating unit 254 analyzes the projection data to detect the image of the linear pattern. This image detection may include segmentation. This segmentation may include, for example, image analysis (image processing) such as threshold processing and edge detection, or may include semantic segmentation using machine learning.

The straightness calculation unit 255 is configured to calculate the straightness of the line scan of the ophthalmic device 1 based on the position data generated by the position data generation unit 254 and the standard information of the linear pattern. This straightness indicates the error of the line scan (its trajectory) relative to a geometric straight line.

Another example of evaluation according to this embodiment will be described. The evaluation unit 250 may be configured to generate position evaluation information regarding the position of the scan applied to the reference as evaluation information. The position of the scan evaluated in this example may be the application position of the scan relative to the reference. When the scan to be position-evaluated consists of multiple subscans, that is, when the scan pattern consists of multiple subpatterns, the position of the scan evaluated in this example may be the relative position of two or more subpatterns applied to the reference, or may be the application position of the subscan relative to the reference.

The pattern formed on the fiducial in this example may include a linear pattern group. The linear pattern group includes two or more linear patterns. The ophthalmic device 1 applies multiple line scans to this fiducial to collect data. The multiple line scans may be, for example, raster scans. The evaluation unit 250 can generate evaluation information on the positional relationship of the multiple line scans as position evaluation information based on the data collected by the multiple line scans and the standard information of the linear pattern group created in advance. The position evaluation information generated here is called positional relationship evaluation information. The evaluation unit 250 may be configured to execute, for example, a process of constructing projection data from data (three-dimensional image data) collected from the fiducial by raster scanning, a process of analyzing the projection data to detect the image of each linear pattern, and a process of generating positional relationship evaluation information based on the detected image of the linear pattern group and the standard information of the linear pattern group. Here, the process of detecting the image of the linear pattern group may include any segmentation.

The linear pattern group formed on the reference device may include two (or more) linear patterns that are parallel to each other. In this case, the ophthalmic device 1 can evaluate the scan interval. In other words, an evaluation can be made regarding the distance between these two line scans.

An example of the configuration of the evaluation unit 250 for evaluating the scan interval is shown in FIG. 4C. The evaluation unit 250C in this example includes a distance data generation unit 256 and a distance evaluation information generation unit 257. The ophthalmic device 1 collects data by applying multiple line scans to a reference device on which two (or more) parallel linear patterns are formed. The multiple line scans may be, for example, raster scans.

The interval data generating unit 256 is configured to generate data indicating the interval between the two linear patterns (i.e., the distance between the two linear patterns) based on the data collected by the multiple line scans. The data generated by the interval data generating unit 256 is called interval data. For example, the interval data generating unit 256 may be configured to execute a process of constructing projection data from data (three-dimensional image data) collected from a reference device by raster scanning, a process of analyzing the projection data to detect an image of each linear pattern, and a process of calculating the distance (interval data) between the images of the two detected linear pattern groups. Here, the process of detecting the images of the linear pattern groups may include any segmentation.

The interval evaluation information generating unit 257 is configured to generate interval evaluation information regarding the interval between two line scans corresponding to two linear patterns, based on the interval data generated by the interval data generating unit 256 and standard information of the two linear patterns created in advance. The generated interval evaluation information is an example of positional relationship evaluation information.

The linear pattern group formed on the reference device may include a plurality of linear patterns parallel to each other. In this case, the ophthalmic device 1 can perform an evaluation regarding overscan. Overscan is a technique for constructing an image excluding data from the periphery of the area to which the scan is applied. When scanning is performed using an optical scanner 44 that performs reciprocating motion like a galvano scanner, the motion of the scanner becomes unstable in the section before and after switching the direction of motion. For example, a sudden change (sudden deceleration and sudden acceleration) in the speed of motion of the scanner occurs in that section. As a result, artifacts such as image distortion occur. Overscan is a technique for constructing an image excluding the part where such artifacts occur. In this aspect, for example, the artifact occurrence area can be obtained from the performance and specifications of the optical scanner 44 to create standard information. The evaluation of overscan in this example can provide a method for providing information on whether the artifact occurrence area is appropriately set, for example. In addition, the evaluation of overscan in this example may be capable of providing the presence or absence, degree, amount, acceptability, etc. of artifacts related to overscan.

An example of the configuration of the evaluation unit 250 for evaluating overscan is shown in FIG. 4D. The evaluation unit 250D in this example includes a distance data generation unit 258, a distance evaluation information generation unit 259, a distribution generation unit 260, and an overscan evaluation information generation unit 261. The ophthalmic device 1 collects data by applying multiple line scans to a reference device on which multiple linear patterns parallel to each other are formed. The multiple line scans may be, for example, raster scans.

The interval data generation unit 258 and the interval evaluation information generation unit 259 have the same configuration as the interval data generation unit 256 and the interval evaluation information generation unit 257 in FIG. 4C, respectively, and execute the same processing. The multiple linear patterns that are parallel to each other are referred to as the first to Nth linear patterns in the order in which they are arranged (N is an integer equal to or greater than 2).

The spacing data generating unit 258 obtains spacing data between the nth linear pattern and the n+1th linear pattern (n=1, 2, ..., N-1). In other words, the spacing data generating unit 258 calculates the distance between any two adjacent linear patterns.

Furthermore, the interval evaluation information generating unit 259 generates interval evaluation information for the nth linear pattern and the n+1th linear pattern based on the interval data obtained for the nth linear pattern and the n+1th linear pattern and the standard information created in advance for the nth linear pattern and the n+1th linear pattern. This results in N-1 pieces of interval evaluation information corresponding to the N-1 pairs obtained from the N linear patterns.

The distribution generation unit 260 is configured to generate information representing the distribution of the N-1 pieces of interval evaluation information thus obtained. The generated information is called the interval evaluation information distribution. For example, the distribution generation unit 260 can generate the interval evaluation information distribution by determining the position of each of the N-1 pieces of interval evaluation information according to the arrangement of the N linear patterns (e.g., relative arrangement or arrangement on a reference device).

The overscan evaluation information generation unit 261 is configured to generate evaluation information regarding overscan (overscan evaluation information) based on the interval evaluation information distribution generated by the distribution generation unit 260 and standard information on overscan created in advance. The generated overscan evaluation information is an example of positional relationship evaluation information.

Another example of the evaluation according to this embodiment will be described. This example can be used to evaluate a measurement method that applies multiple scans to the same part of an object (i.e., to evaluate the reproducibility of the scan). Examples of such measurement methods in the field of ophthalmology include OCT angiography (OCT angiography), which emphasizes blood vessels from the difference between multiple images of the test eye, image averaging, which averages multiple images of the test eye to remove random noise, and a method of generating time-series data from multiple images of the test eye (e.g., OCT blood flow measurement, motion measurement, etc.). These measurement methods require repeatedly scanning the same area of the object (test eye) with high accuracy. This example evaluates whether the position reproducibility of such repeated scans is sufficient.

In this example, the ophthalmic device 1 applies repeated scans to the fiducial. That is, the ophthalmic device 1 performs multiple scans of the same pattern targeting the same area of the fiducial. This results in multiple data collected from the fiducial by scanning the same pattern.

Note that although these multiple data sets are collected by multiple scans targeting the same area, they are not necessarily collected from the same area. If the position repeatability of the scan is low, the multiple data sets will have been collected from substantially different areas. Here, the criterion (threshold) for determining whether the position repeatability is sufficient may be set according to the type of measurement method.

An example of the configuration of the evaluation unit 250 for evaluating the position repeatability of a repetitive scan is shown in FIG. 4E. The evaluation unit 250E in this example includes a repeatability evaluation information generation unit 262. The repeatability evaluation information generation unit 262 generates evaluation information (repeatability evaluation information) of the position repeatability of this repetitive scan based on multiple data collected by the repetitive scan. The generated repeatability evaluation information is an example of position evaluation information.

Next, the visualization information generation unit 270 will be described. The visualization information generation unit 270 generates visualization information from the evaluation information generated by the evaluation unit 250. The visualization information is information that visually represents at least a part of the evaluation information or information obtained therefrom.

The evaluation information input to the visualization information generation unit 270 may be any type of evaluation information collected by scanning a reference instrument, and may be, for example, any of the following exemplary evaluation information: evaluation information based on projection data; evaluation information based on standard information of a pattern formed on a reference instrument; evaluation information of the linearity (straightness) of a line scan; evaluation information of the scan position (position evaluation information); evaluation information of the positional relationship of multiple line scans (positional relationship evaluation information); evaluation information of the spacing between line scans (spacing evaluation information); evaluation information of overscan (overscan evaluation information); evaluation information of the positional repeatability of repetitive scans (reproducibility evaluation information); evaluation information that is a combination of any two or more of the above examples; evaluation information similar to any of the above examples; evaluation information based on any of the above examples. Specific examples of visualization information will be described later.

The above describes an overview of evaluation units 250A to 250E, which are examples of the evaluation unit 250. Below, we will explain some specific aspects of the evaluation of the ophthalmic device 1 that can be performed using such an evaluation unit 250.

In some specific embodiments, for example, a model eye is used to evaluate the ophthalmic device 1. The model eye is provided with a reference device. As described above, a pattern designed based on one or more scanning conditions of the ophthalmic device 1 is formed on the reference device. The reference device is used, for example, as a part of the model eye that corresponds to the fundus (imitation fundus). The reference device is not limited to the simulation fundus, and may be a part of the model eye that corresponds to any part of the eye. The reference device does not have to be part of the model eye, and may be, for example, a reference device alone, or may be provided as part of the simulation fundus.

An example of a model eye is shown in Figure 5. In this example, the model eye 500 is placed in front of the objective lens 22 to evaluate the performance of the ophthalmic device 1. For example, the model eye 500 is attached to a face holder (chin rest, forehead rest, etc.) via a dedicated attachment. This places the model eye 500 in a position similar to the subject eye E. The alignment function of the ophthalmic device 1 can be used to align the ophthalmic device 1 with the model eye 500. This makes it possible to facilitate the task of evaluating the ophthalmic device 1, and also makes it possible to evaluate the ophthalmic device 1 while taking into account an evaluation of the quality of the alignment.

The model eye 500 includes a cornea portion 510 (cornea-equivalent lens) corresponding to the cornea, an iris portion 520 corresponding to the iris, a lens portion 550 (lens equivalent to the lens) corresponding to the crystalline lens, a vitreous portion 560 corresponding to the vitreous body, and a fundus portion 570 corresponding to the fundus. The number of elements included in the model eye 500 (e.g., the number of lenses) is arbitrary.

The iris portion 520 forms an opening 540 corresponding to the pupil. The iris portion 520 may be provided with a variable portion 530 for changing the size (opening diameter) of the opening 540. The variable portion 530 is, for example, detachable from the iris portion 520, and multiple members corresponding to different opening diameters are selectively applied. Alternatively, the variable portion 530 is configured to be movable relative to the iris portion 520. The size of the opening 540 may be fixed. The vitreous portion 560 is filled with a liquid such as oil. The substance filled in the vitreous portion 560 is arbitrary, and may be, for example, any gas, any liquid, or any solid. A gas (air) typically exists in the space between the cornea portion 510 and the lens portion 550. The substance provided in the space between the cornea portion 510 and the lens portion 550 is arbitrary, and may be, for example, any gas, any liquid, or any solid.

The fundus section 570 is a simulated fundus and includes a fiducial. Details and specific examples of the fiducial will be described later.

The fundus portion 570 may have a layered structure corresponding to the fundus of a human eye. For example, the fundus portion 570 may have one or more layers corresponding to any tissue of the fundus of a human eye. Fundus tissues include the inner limiting membrane, nerve fiber layer, ganglion cell layer, inner plexiform layer, inner nuclear layer, outer plexiform layer, outer nuclear layer, external limiting membrane, photoreceptor layer, retinal pigment epithelium layer, Bruch's membrane, choroid, and sclera. The thickness and refractive index of each layer formed in the fundus portion 570 may be equivalent to the thickness and refractive index of one or more corresponding tissues.

The shape of the fundus portion 570 is not limited to a flat plate shape as shown in FIG. 5, and may be a curved shape. For example, the shape of the fundus portion 570 may be a part of a sphere or a part of an ellipsoid that imitates the shape of the fundus of the human eye.

The fundus 570 may have a structure corresponding to any part or tissue of the human eye. For example, the fundus 570 may have a structure corresponding to the macula, a structure corresponding to the optic disc, a structure corresponding to blood vessels, etc. The fundus 570 may also have a structure corresponding to any disease, any pathological condition, or any lesion. For example, the fundus 570 may have a structure corresponding to age-related macular degeneration (AMD) (drusen, etc.), a structure corresponding to retinal detachment, a structure corresponding to bleeding, a structure corresponding to a tumor, a structure corresponding to atrophy, etc.

The parameter values of the model eye 500 may be designed to be equivalent or similar to those of a human eye. The parameter values of the model eye 500 are obtained, for example, from a standard model eye or clinical data. Standard model eyes include the Gullstrand model eye, the Navarro model eye, the Liou-Brennan model eye, the Badal model eye, the Arizona model eye, the Indiana model eye, any standardized model eye, and model eyes equivalent to any of these. The model eye 500 may also be designed based on an eye having a disease such as high myopia. For example, the curvature of the fundus (reference device) of the model eye corresponding to high myopia is designed to be larger than the curvature of the fundus (reference device) of another model eye (for example, a model eye corresponding to a normal eye). The model eye 500 may also have a structure corresponding to any disease, any pathological condition, or any lesion. For example, the model eye 500 may have a structure corresponding to any corneal disease, any lens disease, or the like. The eye model 500 may also have a structure equivalent to an artificial object. For example, the eye model 500 may have an intraocular lens (IOL) or a structure equivalent thereto.

The distance between the center position of the anterior surface of the cornea portion 510 (the position corresponding to the corneal apex) and the anterior surface of the fundus portion 570 may be designed based on the axial length of the human eye. In addition, the overall focal length of the cornea portion 510, the lens portion 550, and the vitreous portion 560 may be designed to be equal to the focal length of the human eye. For example, the model may have a means (e.g., a spacer) for changing the optical distance between the lens portion 550 and the fundus portion 570. This makes it possible to change the refractive power of the model eye 500, and, for example, to perform imaging and measurement evaluation of an eye with a long axial length.

The reflectance of the front surface (surface facing the cornea 510) of the iris portion 520 (variable portion 530) may be designed to be equivalent to that of the human eye. This reflectance may be, for example, the reflectance of infrared wavelengths. Similarly, the front surface of the cornea portion 510 can also be designed to be equivalent to that of the human eye. In addition, the model eye 500 may be designed so that the entrance pupil of the iris portion 520 (variable portion 530, opening 540) is positioned at a position equivalent to that of the entrance pupil of the iris of the human eye.

To prevent the light used to scan the model eye 500 (in this embodiment, the measurement light LS) and the light used for alignment (in this embodiment, the alignment light output from the LED 51) from being multiple-reflected within the model eye 500, it is possible to provide an anti-reflective coating on the lenses, etc., or to apply an anti-reflective paint to the internal components.

When performing alignment based on the pupil, such as alignment using a stereo camera, the following parameter values can be set, for example. First, the entrance pupil of the aperture 540 may be located at a position approximately 3.06 millimeters away from the cornea portion 510. Furthermore, the diameter of the aperture 540 may be set to a value within the range of 2 to 10 millimeters. In addition, the infrared light reflectance of the iris portion 520 (variable portion 530) may be set to a value within the range of 2.0 to 2.5 percent. With such a design, it becomes possible to perform alignment with respect to the model eye 500 based on the aperture 540, similar to the case of performing alignment based on the pupil of the human eye.

Even when other alignment methods are used, the parameter values of the model eye 500 are set according to the method. For example, when alignment is performed using a corneal reflection image (Purkinje image), the radius of curvature of the cornea portion 510 (the radius of curvature of the front surface of the cornea-equivalent lens) may be set to approximately 7.7 millimeters. Similarly, when alignment is performed using an optical lever, the radius of curvature of the cornea portion 510 (the radius of curvature of the front surface of the cornea-equivalent lens) can be set to approximately 7.7 millimeters.

Next, the reference device will be described. In this embodiment, the reference device is a part of the model eye 500 (fundus portion 570), but the embodiment is not limited to this. For example, the reference device in some embodiments may be used alone for evaluation or may be built into the ophthalmic device.

An example of the datum of this embodiment is shown in Figures 6A and 6B. Figure 6A is a front view (top view) of the datum 600 of this embodiment, and Figure 6B is a cross-sectional view showing the A-A section (xy section) of Figure 6A.

The reference device 600 has multiple linear patterns formed vertically and horizontally. In other words, the reference device 600 has a checkerboard (lattice, grid) pattern formed on it.

As shown in FIG. 6B, the pattern in this example is formed by recesses (grooves), but some patterns may be formed by protrusions. In addition, some patterns may be formed by two or more materials with different optical properties. For example, a base (substrate, board, etc.) can be made of a first material having a first scattering property, and a pattern portion can be formed of a second material having a second scattering property different from the first scattering property. Alternatively, a reference device with a groove formed therein can be made of a first material, and a second material can be placed in the groove (for example, the second material can be filled in the groove). Note that the optical property is not limited to the scattering property, and may be any optical property such as an absorption property, a reflection property, a transmission property, or a polarization property.

As described above, a grid pattern is formed on the reference device 600. This grid pattern includes a plurality of linear patterns 601 along a first direction and a plurality of linear patterns 602 along a second direction different from the first direction. In this example, the first direction and the second direction are orthogonal to each other, but the embodiment is not limited to this, and for example, in some aspects, the first direction and the second direction may be oblique to each other.

When the ophthalmic device 1 is used, the reference device 600 (model eye 500) is positioned relative to the ophthalmic device 1 so that the first direction is approximately aligned with the y direction and the second direction is approximately aligned with the x direction. This configuration and positioning corresponds to, for example, line scanning in the x direction, line scanning in the y direction, cross scanning, multi-cross scanning, and raster scanning.

The linear patterns 601 aligned along the first direction are arranged substantially parallel to one another and at substantially equal intervals I. In other words, the linear patterns 601 aligned along the first direction are periodically formed in the arrangement direction (second direction). The linear patterns 601 have substantially equal dimensions. As shown in FIG. 6B, the linear patterns 601 have substantially equal widths W and substantially equal depths D.

Similarly, the multiple linear patterns 602 along the second direction are arranged substantially parallel to each other and at substantially equal intervals. In other words, the multiple linear patterns 602 along the second direction are formed periodically in the arrangement direction (first direction). Here, the interval between the multiple linear patterns 602 may be equal to or different from the interval I between the multiple linear patterns 601. In addition, the dimensions of the multiple linear patterns 602 are substantially equal. Here, the dimensions (width, depth, etc.) of the linear patterns 602 may be equal to or different from the dimensions (width W, depth D, etc.) of the linear patterns 601.

The relationship between the parameters (dimensions, intervals, etc.) of the multiple linear patterns 601 and the corresponding parameters of the multiple linear patterns 602 may be designed based on the scan conditions used in the evaluation of the ophthalmic device 1. For example, if the intervals in the x direction and the y direction of the multiple scan points (multiple lattice points) in the raster scan used in the evaluation are equal, the interval I of the multiple linear patterns 601 and the interval (I) of the multiple linear patterns 602 can be made equal to each other. Also, if the intervals in the x direction and the y direction of the multiple scan points (multiple lattice points) in the raster scan used in the evaluation are different, the interval I of the multiple linear patterns 601 and the interval I of the multiple linear patterns 602 can be made different from each other.

Although the fiducial 600 shown in Figures 6A and 6B has a pattern formed on its surface, embodiments are not limited thereto, and for example, in some aspects, a fiducial can be prepared that has a pattern formed therein.

In this example, the reference device 600 is a flat plate-shaped member, but the embodiment is not limited to this. For example, the reference device 600 may be a member having a curved surface, or may be a curved plate-shaped member. Such a curved shape mimics the shape of the fundus of the human eye.

The material of the reference device 600 may be any material, for example, porous glass. More generally, the material of the reference device 600 may be any material that has scattering properties in the wavelength band of the measurement light LS (near-infrared light), for example, porous silica glass.

The reference numeral 601a in FIG. 6B indicates the central axis (center position) of the linear pattern 601. In this embodiment, the shape (width W) of the linear pattern 601 is created under the condition that the degree of symmetry is 1% or less when a plane that passes through the central axis 601a and extends in the z direction is used as a symmetry plane (datum plane).

7A and 7B show examples of scans applied to the reference 600 for evaluation of the ophthalmic device 1. Reference numeral 700 in FIG. 7A indicates the application area (outer edge, contour) of the scan of this example on the reference 600. The scan of this example is a three-dimensional scan applied to a three-dimensional region of the reference 600 whose range in the xy direction is defined by the scan area 700. An example of this three-dimensional scan is shown in FIG. 7B. The three-dimensional scan of this example is a raster scan consisting of multiple line scans 700-k (k=1, 2, ..., K: K is a positive integer) along the x direction. The K line scans 700-1 to 700-K are parallel to each other. In some aspects, a raster scan consisting of multiple line scans along the y direction can be applied to the reference 600. Note that the scan aspects (raster scan aspects, three-dimensional scan aspects, etc.) are not limited to these.

An example of a luminance profile obtained using such a scan is shown in Figure 8. The luminance profile in this example is generated by constructing three-dimensional image data from data collected from a three-dimensional area of the fiducial 600 by raster scanning, projecting this three-dimensional image data in the z direction to construct projection data, and determining the luminance distribution on a line along the x direction of this projection data.

The horizontal and vertical axes of the luminance profile in FIG. 8 indicate the x coordinate (position in the x direction) and luminance value, respectively. Each plot point indicates the luminance value at the corresponding x coordinate. The graph is obtained by interpolating the plot points with a spline curve. Each dashed line parallel to the vertical axis indicates the estimated position of the center of gravity (groove center of gravity) of the groove (recess, linear pattern 601) of the reference device 600. The distance between two adjacent groove centers of gravity is an estimate of the spacing between two corresponding linear patterns 601.

Below, we explain some specific examples of evaluation of the ophthalmic device 1 using such a reference device 600 and raster scans 700-1 to 700-K.

A first specific example of the evaluation will be described with reference to FIG. 9. In this example, an evaluation of the straightness of the line scan of the ophthalmic device 1 is performed. First, the model eye 500 (reference device 600) is placed (S1). For example, the model eye 500 is attached to a chin rest via a dedicated attachment. The manner in which the model eye 500 is attached is not limited to this.

After the model eye 500 is attached, the ophthalmic device 1 starts alignment of the model eye 500 (S2). The alignment may be performed by any of the exemplary methods described above.

Once the alignment is complete, the ophthalmic device 1 applies an OCT scan to the fiducial 600 of the model eye 500 (S3). The OCT scan in this example is a raster scan as shown in Figures 7A and 7B.

Next, the ophthalmic device 1 constructs three-dimensional image data from the data collected by the raster scan in step S3 (S4), and constructs projection data from this three-dimensional image data (S5).

The ophthalmologic apparatus 1 further creates a luminance profile similar to that shown in FIG. 8 from this projection data (S6). The luminance profile is created for at least one line. The at least one line for which the luminance profile is created may include at least one of a line along the x direction, a line along the y direction, and a line along another direction. Typically, a luminance profile can be created for a line parallel to the line scan 700-k shown in FIG. 7B (in this example, a line along the x direction). This allows the straightness of the line scan 700-k to be evaluated. When determining the straightness of a line along a direction different from the x direction, the arrangement state of two or more line scans 700-k (such as their arrangement state in the y direction) can be evaluated.

Then, the ophthalmic device 1 detects the sulcus centroid from the luminance profile created in step S6 (S7). Any method may be used to detect (estimate) the sulcus centroid. For example, the luminance profile in FIG. 8 may be analyzed to identify the local lowest end position, and the local highest end positions in the vicinity (on both sides) of the identified local lowest end position may be identified, and the estimated position of the sulcus centroid may be obtained from these identified positions.

Next, the ophthalmic device 1 identifies the coordinates of each groove centroid identified in step S7 (S8). Here, at least the x coordinate of the groove centroid is identified. This allows the coordinates (at least the x coordinate) of each linear pattern 601 that intersects with the line on which the luminance profile has been created to be obtained. In other words, the distribution of the centroid positions of the multiple linear patterns 601 on that line is obtained.

Next, the ophthalmic device 1 calculates the interval between the groove centroids from the coordinates of the multiple groove centroids identified in step S8 (S9). The calculation of the groove centroid interval may be performed for each pair of adjacent groove centroids, or may be performed for a pair selected from these pairs. In addition, when the groove centroid interval is calculated for two or more pairs, statistics (e.g., average, mode, median, variance, standard deviation, etc.) of the two or more obtained groove centroid intervals may be calculated. Alternatively, the groove centroid interval may be estimated by calculating the distance between two non-adjacent groove centroids and dividing the calculated distance by a value obtained by adding 1 to the number of other groove centroids that exist between the two groove centroids.

Next, the ophthalmic device 1 generates evaluation information based on at least one of the groove centroid coordinates identified in step S8, the groove centroid interval calculated in step S9, and information obtained from at least one of these (S10).

In this example, the standard information of the reference device 600 is stored in the storage unit 212. The standard information in this example includes standard information on the groove centroid position (groove centroid coordinate), standard information on the groove centroid interval, and standard information on parameters obtained from the groove centroid position and/or the groove centroid interval. The ophthalmic device 1 can generate evaluation information on the linearity of the scan by comparing the groove centroid coordinate identified in step S8, the groove centroid interval calculated in step S9, and information obtained from at least one of them, with such standard information. For example, the ophthalmic device 1 can calculate the difference between the groove centroid coordinate identified in step S8 and the groove centroid position (coordinate) included in the standard information, and can obtain the linearity evaluation information (straightness) of the line scan 700-k based on the calculated difference (i.e., the deviation of the groove centroid coordinate actually measured relative to the standard groove centroid position). In addition, the ophthalmic device 1 calculates the difference between the groove centroid spacing calculated in step S9 and the groove centroid spacing included in the standard information, and can obtain linearity evaluation information (straightness) of the line scan 700-k based on the calculated difference (i.e., the error between the actually measured groove centroid spacing and the standard groove centroid spacing).

Then, the ophthalmic apparatus 1 generates visualization information from the evaluation information generated in step S10 (S11). The ophthalmic apparatus 1 can display the generated visualization information on the display unit 241. The visualization information may be, for example, a map (such as a heat map) showing the distribution of the evaluation information, a brightness profile (such as a graph or plot), or the like. Specific examples of the visualization information will be described later.

The ophthalmologic device 1 can transmit the evaluation information and visualization information to an external device and can also record them on a recording medium. This concludes the explanation of the first specific example of evaluation (END).

A second specific example of the evaluation will be described with reference to FIG. 10. This example is for evaluating the straightness of the line scan of the ophthalmic device 1. Steps S21 to S25 may be performed in the same manner as steps S1 to S5 of the first specific example.

Furthermore, the ophthalmic device 1 creates a luminance profile similar to that shown in FIG. 8 from the projection data constructed in step S25. In this example, the ophthalmic device 1 creates at least one luminance profile along the x direction and at least one luminance profile along the y direction (S26).

Then, the ophthalmic device 1 detects the groove centroid from each luminance profile created in step S26 (S27). This process may be performed in the same manner as step S7 in the first specific example. Furthermore, the ophthalmic device 1 identifies the coordinates of each groove centroid identified in step S27 (S28). Here, the x-coordinate and y-coordinate (i.e., coordinates in the xy coordinate system) of the groove centroid are identified.

Next, the ophthalmologic apparatus 1 creates a scatter diagram by plotting the positions of the groove centroids in a predetermined two-dimensional coordinate system based on the x- and y-coordinates of the groove centroids identified in step S28 (S29). For example, the horizontal and vertical axes of this two-dimensional coordinate system represent the distance in the x- and y-directions, respectively. The unit of distance is, for example, micrometers.

Some examples of data generated in step S29 are shown in FIG. 11. Reference numeral 800 indicates a portion of the reference device (scan application area) corresponding to the scan area 700 in FIG. 7A. Reference numeral 801 indicates one line along the x direction in the scan application area 800, and reference numerals 802 and 803 indicate two lines along the y direction. Reference numeral 811 indicates a scatter diagram created by plotting the positions of multiple groove centroids on line 801. Similarly, reference numeral 812 indicates a scatter diagram created by plotting the positions of multiple groove centroids on line 802, and reference numeral 813 indicates a scatter diagram created by plotting the positions of multiple groove centroids on line 803.

Next, the ophthalmic device 1 applies polynomial fitting to each scatter diagram created in step S29 (S30). The polynomial used in this polynomial fitting may be, for example, at least one of a quadratic polynomial, a cubic polynomial, and a quartic polynomial. Note that any curve fitting may be performed instead of or in addition to the polynomial fitting.

Then, the ophthalmic device 1 generates linearity evaluation information (straightness) based on the coefficients of the polynomial obtained by the polynomial fitting performed in step S30 (S31). More specifically, the ophthalmic device 1 can generate linearity evaluation information based on the magnitude of the coefficients of the polynomial. For example, the value of the coefficient can be converted into a straightness value according to a conversion formula generated in advance by utilizing the property that the coefficient becomes zero if the deviation of the groove center of gravity is small and close to a straight line. Alternatively, the linearity can be judged from the value of the coefficient based on a threshold value generated in advance by utilizing the same property.

Furthermore, the ophthalmic device 1 can generate visualization information from the evaluation information generated in step S31. In addition, the ophthalmic device 1 can display the generated visualization information on the display unit 241. Furthermore, the ophthalmic device 1 can transmit the evaluation information and the visualization information to an external device or record them on a recording medium. This concludes the explanation of the second specific example of evaluation (END).

A third specific example of the evaluation will be described with reference to FIG. 12. This example provides an example of visualized information that visually represents the evaluation information. The visualized information in this example represents the distribution of groove center-of-gravity intervals in a scan application area 800 similar to that in FIG. 11.

Reference numeral 821 denotes a groove spacing map that is a two-dimensional mapping of the groove spacing in the x direction at multiple positions in the scan application area 800. For example, the groove spacing 805 in the x direction at a certain position is represented at the corresponding position (position indicated by the arrow) in the groove spacing map 821.

Similarly, reference numeral 822 denotes a groove spacing map that is a two-dimensional mapping of groove spacing in the y direction at multiple positions in the scan application area 800. For example, groove spacing 804 in the y direction at a certain position is represented at its corresponding position (position indicated by an arrow) in the groove spacing map 822.

The groove spacing maps 821 and 822 may be color maps that express the magnitude of the groove spacing value with different colors. A color code indicating the correspondence between the groove spacing value and the color is arranged on the right side of the groove spacing map 821 as a color map. Similarly, a color code indicating the correspondence between the groove spacing value and the color is arranged on the right side of the groove spacing map 822 as a color map. The ophthalmic device 1 assigns a corresponding color in the color code to the groove spacing value at each position.

In some embodiments, the color code is set so that the larger the groove spacing value, the closer to yellow, and the smaller the groove spacing value, the closer to blue.

At least one of the groove spacing maps 821 and 822 may be visualization information in a form different from a color map. For example, a map in which the groove spacing value is expressed by contrast or a pattern may be used. The groove spacing may also be expressed by a numerical value.

In this example, the groove spacing is defined as the distance between two adjacent groove centers of gravity, but the embodiment is not limited to this. For example, in some aspects, the groove spacing may be defined as the deviation (distance value, variance value, standard deviation value, etc.) of each groove spacing from a representative value (average value, mode, median, etc.) of multiple groove spacings.

In addition, by setting a threshold value for groove spacing in advance and comparing the groove spacing value at each position with this threshold value, it is possible to determine whether the groove spacing at each position is good or bad. Furthermore, it is possible to provide visualized information showing the results of this pass/fail judgment. For example, it is possible to provide a map showing the distribution of pass/fail judgment results.

A fourth specific example of evaluation will be described with reference to FIG. 13. This example provides an example of visualization information that visually represents evaluation information. The visualization information in this example visually represents overscan evaluation information for the scan application area 800 similar to that in FIG. 11.

As mentioned above, the evaluation of overscan may provide, for example, whether the artifact occurrence area is set appropriately, the presence, degree, amount, and acceptability of overscan-related artifacts, etc.

In this example, the ophthalmic device 1 can evaluate the state of the image in the end region in the x-direction of the scan application area (800) in the manner described above. Here, the x-direction is the direction along each line scan 700-k.

The ophthalmic device 1 can determine the relative positions of two images corresponding to a pair of adjacent line scans 700-k and 700-(k+1) in the x-direction end region of the scan application area (800). For example, the ophthalmic device 1 can determine at least one of the distance (spacing) in the y direction between these two images and the deviation in the x direction. In addition, the ophthalmic device 1 can determine the uniformity (evenness) of the spacing in the x direction of multiple A-scan image data included in the image (B-scan image data) corresponding to the line scan 700-k.

The ophthalmologic apparatus 1 can generate visualization information that visually represents the overscan evaluation information based on such overscan evaluation parameter information. The visualization information (overscan evaluation map) 823 related to overscan shown in FIG. 13 represents the distribution of the overscan evaluation parameter information in the scan application area 800 (particularly, the end regions 824 and 825 in the x direction) similar to that in FIG. 11.

The overscan evaluation map 823 may be a color map that expresses the magnitude of the value of the overscan evaluation parameter with different colors. A color code indicating the correspondence between the value of the overscan evaluation parameter and the color is arranged on the right side of the overscan evaluation map 823 as a color map. The ophthalmic device 1 assigns a corresponding color in the color code to the value of the overscan evaluation parameter at each position. As with the third specific example, the overscan evaluation map 823 may be visualized information in a form different from the color map.

In addition, by setting a threshold value for the overscan evaluation parameter in advance and comparing the value of the overscan evaluation parameter at each position with the threshold value, it is possible to determine whether the overscan evaluation parameter at each position is good or bad. Furthermore, it is possible to provide visualized information showing the results of this pass/fail determination. For example, it is possible to provide a map showing the distribution of pass/fail determination results.

A fifth specific example of evaluation will be described. This example provides evaluation information and visualization information regarding the position repeatability of repetitive scans performed in OCT angiography, image averaging, OCT blood flow measurement, motion measurement, etc. An example of the process for generating the repeatability evaluation information and its visualization information is shown in FIG. 14. Steps S41 and S42 may be performed in the same manner as steps S1 and S2 of the first specific example, respectively.

Once the alignment in step S42 is complete, the ophthalmic device 1 applies an iterative scan to the model eye 500 (S43). In other words, the ophthalmic device 1 performs multiple scans targeting the same location on the fiducial 600. The iterative scans in this example are multiple raster scans.

The number of repetitions in the repetitive scan may be any number of times, two or more. The number of repetitions may be determined, for example, according to the type of measurement method to be evaluated. In some embodiments, when the measurement method to be evaluated is OCT angiography, the number of repetitions in the repetitive scan may be four, which is the same as the number of scans performed in OCT angiography targeting the same location. The number of repetitions when other measurement methods are to be evaluated may be determined in the same manner. In this example, four raster scans are performed targeting the same location (scan application area 800) of the reference device 600.

The ophthalmic device 1 constructs three-dimensional image data from each of the four collected data sets obtained by the repeated scan in step S43. This results in four pieces of three-dimensional image data corresponding to the four raster scans (S44). Furthermore, the ophthalmic device 1 constructs projection data from each piece of three-dimensional image data constructed in step S44. This results in four pieces of projection data corresponding to the four raster scans (S45).

Next, the ophthalmic device 1 creates a luminance profile similar to that shown in FIG. 8 from each projection data obtained in step S45 (S46). In this example, the ophthalmic device 1 creates, for example, one or both of a plurality of luminance profiles along the x direction and a plurality of luminance profiles along the y direction. This results in four groups of luminance profiles corresponding to the four raster scans.

Next, the ophthalmic device 1 detects sulcus centroids from each luminance profile created in step S46 (S47). This process may be performed in the same manner as step S7 in the first specific example. This results in four groups of sulcus centroids corresponding to the four raster scans.

Next, the ophthalmologic device 1 identifies the coordinates of each groove centroid identified in step S47 (S48). In this example, the x-coordinate and y-coordinate of the groove centroid (i.e., the coordinates in the xy coordinate system) are identified. This results in four groove centroid coordinate groups corresponding to the four raster scans.

Next, for each point of the fiducial 600 (each point within the range to which the repeated scan has been applied; the same applies below in this example), the ophthalmic device 1 selects the groove centroid coordinates corresponding to that point, one at a time, from the group of four groove centroid coordinates identified in step S48. This assigns four groove centroid coordinates to each point of the fiducial 600. In other words, four groove centroids are associated with each point of the fiducial 600. Furthermore, the ophthalmic device 1 calculates, for each point of the fiducial 600, the position error between the four groove centroids associated with that point (S49).

The error calculated in step S49 represents the amount of deviation (displacement, variation) of the scan position (scan range) during four raster scans performed sequentially targeting the same area of the reference device 600. This provides a distribution of the amount of deviation of the scan position in the reference device 600 (the range to which the repeated scans are applied). The value calculated in step S49 may be, for example, any amount calculated from the four groove center positions (coordinates), such as the standard deviation, maximum error, average error, etc.

Next, the ophthalmic device 1 generates reproducibility evaluation information based on the error distribution of the groove centroid position obtained in step S49 (S50). This process may include, for example, a process of comparing at least a portion of the multiple errors obtained in step S49, or a value obtained based thereon, with a predetermined threshold value (threshold processing).

Furthermore, the ophthalmic apparatus 1 generates visualization information (reproducibility visualization information) from the reproducibility evaluation information generated in step S50 (S51). Examples of the form of the reproducibility visualization information will be described later. In addition, the ophthalmic apparatus 1 can display the generated reproducibility visualization information on the display unit 241. Furthermore, the ophthalmic apparatus 1 can transmit the reproducibility evaluation information and the reproducibility visualization information to an external device or record them on a recording medium. This concludes the explanation of the series of processes shown in FIG. 14 (END).

A specific example of the series of processes shown in FIG. 14 will be described with further reference to FIG. 15 and FIG. 16. In this example, as shown in FIG. 15, four projection data 831 to 834 corresponding to four raster scans are obtained.

First, for an arbitrary position (first position) 831a of the first projection data 831, the ophthalmologic device 1 determines a position (second position) 832a of the second projection data 832 that corresponds to this first position 831a.

For example, the ophthalmologic apparatus 1 can identify the x and y coordinates (first x and y coordinates) of the first position in the x and y coordinate system (first x and y coordinate system) in which the first projection data 831 is defined, identify a position having the same x and y coordinates as the first x and y coordinates in the x and y coordinate system (second x and y coordinate system) in which the second projection data 832 is defined, and set this identified position as the second position 832a. The determination of the position (third position) 833a of the third projection data 833 corresponding to the first position 831a and the determination of the position (fourth position) 834a of the fourth projection data 834 corresponding to the first position 831a can also be performed in the same manner. Note that the method of determining the four corresponding positions in the four projection data 831 to 834 is not limited to this.

Next, as shown in FIG. 16, the ophthalmologic device 1 generates information at a position (defined position) defined by these positions 831a to 834a based on data P(1) of the first projection data 831 at the first position 831a (and its vicinity), data P(2) of the second projection data 833 at the second position 832a (and its vicinity), data P(3) of the third projection data 833 at the third position 833a (and its vicinity), and data P(4) of the fourth projection data 834 at the fourth position 834a (and its vicinity).

For example, data P(1) to P(4) may be pixel information at the corresponding first to fourth positions 831a to 834a, respectively, or may be data generated from the pixel information. Data P(1) to P(4) may include pixel information at positions near the corresponding first to fourth positions 831a to 834a, respectively, or may include data generated from pixel information at the positions near the positions. The defined position may be any of the first to fourth positions 831a to 834a (for example, the first position 831a), or may be a position determined from at least two of the first to fourth positions 831a to 834a (for example, the average position).

The information thus obtained is assigned to the defined positions, thereby obtaining the reproducibility visualization information 841 in FIG. 16. The reproducibility visualization information 841 is a color map that represents the distribution of the displacement of the groove center of gravity in the x direction. The positions of the reproducibility visualization information 841 (the above-mentioned defined positions) are assigned colors that correspond to the information (values) generated from the four pieces of data P(1) to P(4) that correspond to the first to fourth positions 831a to 834a, respectively. By performing such processing for each point of the first projection data 831, the reproducibility visualization information 841 is generated, which is a map that represents the distribution as reproducibility evaluation information. The reproducibility visualization information 843, which is a color map that represents the displacement of the groove center of gravity in the y direction, is generated in the same manner.

Another example for generating reproducibility evaluation information will be described. This example uses registration of projection data (or three-dimensional image data). The ophthalmic device 1 provides registration for the first to fourth projection data 831 to 834. This registration may be global registration or local registration.

Global registration is image processing aimed at aligning the overall position of each of the first to fourth projection data 831 to 834. For example, the ophthalmologic apparatus 1 uses the first projection data as reference data and registers each of the second to fourth projection data 832 to 834 with respect to this reference data. Any registration method may be used, but may include, for example, a process of detecting feature points of each projection data 831 to 834 and a process of determining the deviation of each of the second to fourth projection data 832 to 834 with respect to the first projection data 831 based on the position error of the detected feature points. This deviation is used as the amount of positional deviation between the projection data.

Local registration is image processing aimed at aligning partial regions (local regions) of the projection data 831 to 834. For example, the ophthalmic device 1 first uses the first projection data as reference data and sets one local region (reference local region) of the first projection data 831. The dimensions and shape of the reference local region may be arbitrary. For example, an arbitrary point of the first projection data 831 can be specified, and the region in the vicinity of this specified point can be set as the reference local region. Next, the ophthalmic device 1 identifies a partial region equivalent to the reference local region by analyzing each of the second to fourth projection data 832 to 834. This makes it possible to obtain the amount of local positional deviation between the first projection data 831 and each of the second to fourth projection data 832 to 834. For example, it is possible to obtain the amount of positional misalignment between an arbitrary point (the above-mentioned specified point) of the first projection data 831 and each corresponding point of the second to fourth projection data 832 to 834. By performing such processing for multiple points of the projection data 831, it is possible to obtain the distribution of the amount of positional misalignment between the first to fourth projection data 831 to 834.

Some features, some actions, and some effects of this aspect will be described. Each of the multiple features described below can be a feature of this aspect individually, and any combination of two or more of them can also be a feature of this aspect. Note that the features provided by this disclosure are not limited to those described above.

This aspect provides a reference device for evaluating a scan-type medical device, in which a pattern corresponding to the scanning conditions of the medical device is formed. More specifically, the reference device 600 of this aspect is a reference device for acquiring evaluation information of a medical scanning device (ophthalmic device 1) that scans a living body based on preset scanning conditions to collect data, in which a pattern designed based on at least one scanning condition of the ophthalmic device 1 is formed. This kind of reference device in which a pattern corresponding to the scanning conditions of a medical scanning device is formed is new, and by using this reference device, it becomes possible to perform new evaluation methods for medical scanning devices, such as evaluation of the linearity of the scan, evaluation of the positional repeatability of the scan, and evaluation related to motion contrast imaging (OCT angiography, etc.).

The pattern formed on the fiducial 600 is designed, for example, based on any scanning conditions in the OCT scan performed by the ophthalmic device 1. The scanning conditions referenced in the design of the pattern may include, for example, at least one of the scan pattern, scan dimensions (length, area, volume, diameter, etc.), scan interval, scan density, and number of scan repetitions, and may also include at least one of the other scanning conditions exemplified in this embodiment.

The pattern formed on the fiducial 600 of this embodiment may include at least a first periodic pattern along a first direction. Each of the multiple linear patterns 601 and multiple linear patterns 602 in this embodiment provides an example of such a first periodic pattern. According to this embodiment, for example, evaluation can be performed on one or more scans along the first direction.

The pattern formed on the reference device 600 of this embodiment may further include a second periodic pattern along a second direction different from the first direction. In this embodiment, both the multiple linear patterns 601 and the multiple linear patterns 602 are formed on the reference device 600, and the combination of the multiple linear patterns 601 and the multiple linear patterns 602 provides an example of a combination of a first periodic pattern and a second periodic pattern. That is, one of the multiple linear patterns 601 and the multiple linear patterns 602 provides an example of a first periodic pattern, and the other provides an example of a second periodic pattern. In addition, the combination of the multiple linear patterns 601 and the multiple linear patterns 602 provides an example of a grid pattern. According to such an embodiment, for example, evaluation can be performed on one or more scans along the first direction, and evaluation can also be performed on one or more scans along the second direction. In this embodiment, evaluations are performed on raster scans, one line scan that constitutes a raster scan, two or more line scans that constitute a raster scan, and multiple raster scans. Conventionally, evaluations of scan length, etc. were performed using a reference device on which a cross pattern was formed, but since evaluations could only be performed on the cross pattern, it was not possible to evaluate, for example, diagonal scans, and it was also not possible to evaluate scan distortion. Such inconveniences are eliminated by this embodiment.

At least a part of the pattern formed on the fiducial 600 of this embodiment may be a recess (groove, valley) and/or a protrusion (mountain) formed on the surface or inside. In the example shown in FIG. 6B, the recess formed on the surface of the fiducial 600 constitutes the pattern. Although not shown, the pattern may be formed by forming a protrusion on the surface of the fiducial, or the pattern may be formed by forming a recess and/or a protrusion inside the fiducial. According to such an embodiment, a specific configuration is provided for including information about the pattern in the data collected by scanning.

At least a portion of the pattern formed on the fiducial 600 of this embodiment may be formed from two or more materials with different optical characteristics. For example, although not shown, for a specific optical characteristic, a base (substrate, board, etc.) can be made from a first material having a first characteristic amount, and a pattern portion can be formed from a second material having a second characteristic amount different from the first characteristic amount. According to this embodiment, a specific configuration is provided for including information about the pattern in the data collected by optical scanning.

At least a portion of the pattern formed on the fiducial 600 of this embodiment may be formed from two or more materials with different light scattering properties. According to this embodiment, a specific configuration is provided for including information about the pattern in data collected by optical scanning in a measurement method that utilizes differences in light scattering properties between tissues, such as OCT.

This aspect provides a reference device for evaluating a scan-type ophthalmic device, the reference device having a periodic pattern formed thereon. More specifically, the reference device 600 of this aspect has a spatially periodically arranged pattern, such as a plurality of linear patterns 601 and a plurality of linear patterns 602. The periodic pattern may include a pattern periodically arranged in one direction, or may include a pattern periodically arranged in two or more directions. A reference device for evaluating an ophthalmic device having such a periodic pattern formed thereon is novel, and by using this reference device, it becomes possible to perform new evaluation methods for ophthalmic devices, such as evaluation of the linearity of the scan of the ophthalmic device, evaluation of the positional repeatability of the scan of the ophthalmic device, and evaluation of the motion contrast imaging (OCT angiography, etc.) of the ophthalmic device.

This aspect provides a model eye in which a reference device having at least one of the above-mentioned features is used as a simulated fundus. More generally, this aspect provides a model eye in which a reference device having at least one of the various configurations described in this disclosure is used as a simulated fundus. Note that the model eye provided by this aspect is not limited to this, and for example, the tissue simulated by the reference device may be any tissue of the eye, such as the cornea, lens, iris, or vitreous body.

In the model eye provided by this aspect, at least a portion of the surface of the reference device may be formed as a curved surface. Furthermore, a pattern may be formed on the curved surface or inside the curved surface. According to this aspect, it is possible to evaluate an ophthalmic device using an eye model including a reference device having a curved surface that mimics the shape of the fundus. This makes it possible to more accurately reproduce the scanning conditions that are actually applied to a living eye and perform the evaluation, thereby improving the quality of the evaluation.

This aspect provides a novel medical evaluation device for acquiring evaluation information of a medical scanning device that scans a living body to collect data. This medical scanning device includes a reference device and an evaluation unit. The reference device has a pattern formed thereon that is designed based on at least one scanning condition of the medical scanning device. The evaluation unit generates evaluation information based on data collected by scanning the reference device. For example, the above-mentioned ophthalmic device 1 applies an OCT scan to the subject's eye E to collect data, and includes a reference device 600 on which a pattern designed based on at least one scanning condition of the ophthalmic device 1 is formed, and an evaluation unit 250 (for example, at least one of the evaluation units 250A to 250E).

In some embodiments, the medical evaluation device may be integrated with the medical scanning device. For example, in some embodiments, the medical evaluation device is incorporated into the medical scanning device, in other words, the medical scanning device has the configuration and function for evaluating itself. In contrast, in some embodiments, the medical evaluation device may be separate from the medical scanning device. For example, in some embodiments, the medical evaluation device may be a combination of an information processing device (computer) including an evaluation unit and a reference device. In this way, the implementation form of the medical evaluation device may be arbitrary.

In some embodiments, the pattern formed on the fiducial of the medical evaluation device may include at least a first periodic pattern along a first direction and may further include a second periodic pattern along a second direction different from the first direction. For example, the pattern formed on the fiducial of the medical evaluation device may be a grid pattern.

In some embodiments, at least a portion of the pattern formed on the reference of the medical evaluation device may be recesses and/or protrusions formed on the surface or inside. In some embodiments, at least a portion of the pattern on the reference of the medical evaluation device may be formed from two or more materials with different optical properties, which may include scattering properties.

The present aspect also provides a novel medical evaluation device for acquiring evaluation information of a medical scanning device that scans a living body to collect data. The medical scanning device includes a reference device and an evaluation unit. A periodic pattern is formed on the reference device. The evaluation unit generates evaluation information based on data collected by scanning the reference device. For example, the above-mentioned ophthalmic device 1 applies an OCT scan to the subject's eye E to collect data, and includes a reference device 600 on which a periodic pattern corresponding to a raster scan or the like that can be performed by the ophthalmic device 1 is formed, and an evaluation unit 250 (for example, at least one of the evaluation units 250A to 250E). The medical evaluation device may be implemented in any form.

In some embodiments, the fiducial of the medical scanning device may be a simulated fundus of a model eye. In a fiducial as a simulated fundus, at least a portion of the surface of the fiducial may be formed as a curved surface, and further, the pattern formed on the fiducial may be formed on or within the curved surface.

In some aspects, the medical scanning device may be configured to perform an evaluation based on the projection data. Such a medical scanning device collects three-dimensional data by applying a scan to a three-dimensional area of a fiducial. The evaluation unit includes a projection processing unit and an evaluation information generating unit. The projection processing unit is configured to construct projection data (two-dimensional data) from the collected three-dimensional data. The evaluation information generating unit is configured to generate evaluation information based on the constructed projection data. It is clear to those skilled in the art that the above-mentioned ophthalmic device 1 has such a configuration. According to such an aspect, evaluation can be performed using two-dimensional information represented by the projection data, which has the advantage of requiring fewer processing resources and processing time than using collected three-dimensional information. For example, in various evaluations performed by the above-mentioned ophthalmic device 1, z-coordinate information is not necessary, and it can be said that there is no particular problem even if the dimension is reduced to projection data defined in an xy coordinate system.

In some aspects, the evaluation unit of the medical scanning device may be configured to generate evaluation information based on data collected by scanning the fiducial and standard information of the pattern formed on the fiducial. As described above, the standard information of the pattern can be created in advance, for example, based on design information of the fiducial and/or measurement data of the fiducial. It will be clear to those skilled in the art that the above-mentioned ophthalmic device 1 has such a configuration. According to such an aspect, it becomes possible to more accurately compare the actual pattern formed on the fiducial with the data collected by scanning the fiducial, thereby improving the quality of the evaluation information.

In some embodiments, the evaluation unit of the medical scanning device may be configured to determine the straightness of the line scan applied to the reference device. Straightness (linearity, degree of linearity) is an example of evaluation information. It will be clear to those skilled in the art that the above-mentioned ophthalmic device 1 has such a configuration. According to such an embodiment, it becomes possible to evaluate whether the trajectory of the line scan performed by the medical scanning device can be considered as a straight line, and also to evaluate the degree of deviation of the line scan trajectory from a straight line.

In some embodiments, the pattern of the fiducial of the medical scanning device may include a linear pattern. Furthermore, the evaluation unit may be configured to determine the straightness of the line scan based on data collected by scanning the fiducial and standard information of the linear pattern. It will be apparent to those skilled in the art that the above-mentioned ophthalmic device 1 has such a configuration. According to such an embodiment, a specific configuration for evaluating the straightness of the line scan is provided.

In some aspects, the evaluation unit of the medical scanning device may include a projection processing unit, a position data generation unit, and a straightness calculation unit. The projection processing unit is configured to construct projection data from three-dimensional data collected by scanning a three-dimensional area of the fiducial. The position data generation unit is configured to obtain position data of a linear pattern formed on the fiducial based on the generated projection data. The straightness calculation unit is configured to calculate the straightness of the line scan based on the obtained position data and standard information of the linear pattern. It will be clear to those skilled in the art that the above-mentioned ophthalmic device 1 has such a configuration. According to such an aspect, a more specific configuration for evaluating the straightness of the line scan is provided.

In some embodiments, the medical scanning device may further include a visualization information generation unit that generates visualization information from the evaluation information generated by the evaluation unit. It will be clear to those skilled in the art that the above-described ophthalmic device 1 has such a configuration. According to such an embodiment, it becomes possible to provide a user with visualization information that visually represents the evaluation information of the medical scanning device.

This aspect provides a novel medical evaluation device for obtaining evaluation information regarding the position of a scan of a medical scanning device that scans a living body and collects data. The medical scanning device includes a reference device and an evaluation unit. The reference device has a pattern that is designed based on at least one scanning condition of the medical scanning device. The evaluation unit is configured to generate position evaluation information regarding the position of a scan applied to the reference device based on data collected by scanning the reference device. It is clear to a person skilled in the art that the above-mentioned ophthalmic device 1 has such a configuration. The implementation form of the medical evaluation device may be arbitrary.

In some embodiments, the pattern formed on the fiducial of the medical evaluation device for obtaining evaluation information related to the position of the scan may include at least a first periodic pattern along a first direction and may further include a second periodic pattern along a second direction different from the first direction. For example, the pattern formed on the fiducial of the medical evaluation device may be a grid pattern.

In some embodiments, at least a portion of the pattern formed on the reference of the medical evaluation device for obtaining evaluation information regarding the position of the scan may be a concave and/or convex portion formed on the surface or inside. Also, in some embodiments, at least a portion of the pattern of the reference of the medical evaluation device may be formed of two or more materials with different optical properties, which may include scattering properties.

This aspect provides a novel medical evaluation device for obtaining evaluation information regarding the position of a scan of a medical scanning device that scans a living body and collects data. The medical scanning device includes a reference device and an evaluation unit. A periodic pattern is formed on the reference device. The evaluation unit is configured to generate position evaluation information regarding the position of a scan applied to the reference device based on data collected by scanning the reference device. It is clear to a person skilled in the art that the above-mentioned ophthalmic device 1 has such a configuration. The implementation form of the medical evaluation device may be arbitrary.

In some embodiments, the fiducial of the medical scanning device for obtaining evaluation information regarding the position of the scan may be a simulated fundus of an eye model. In the fiducial as a simulated fundus, at least a portion of the surface of the fiducial may be formed as a curved surface, and further, the pattern formed on the fiducial may be formed on or within the curved surface.

In some aspects, a medical scanning device for obtaining evaluation information regarding the position of a scan may be configured to perform evaluation based on projection data. Such a medical scanning device collects three-dimensional data by applying a scan to a three-dimensional area of a fiducial. The evaluation unit includes a projection processing unit and an evaluation information generating unit. The projection processing unit is configured to construct projection data (two-dimensional data) from the collected three-dimensional data. The evaluation information generating unit is configured to generate evaluation information based on the constructed projection data. It is clear to those skilled in the art that the above-mentioned ophthalmic device 1 has such a configuration. According to such an aspect, evaluation regarding the position of a scan can be performed using two-dimensional information represented by the projection data, which has the advantage of requiring fewer processing resources and processing time than using collected three-dimensional information.

In some aspects, the evaluation unit of the medical scanning device for obtaining evaluation information regarding the position of the scan may be configured to generate the evaluation information based on data collected by scanning the fiducial and standard information of the pattern formed on the fiducial. As described above, the standard information of the pattern can be created in advance, for example, based on design information of the fiducial and/or measurement data of the fiducial. It is clear to those skilled in the art that the above-mentioned ophthalmic device 1 has such a configuration. According to such an aspect, it is possible to more accurately compare the actual pattern formed on the fiducial and the data collected by scanning the fiducial, thereby improving the quality of the evaluation information regarding the position of the scan.

In some aspects, the pattern formed on the reference of the medical scanning device for obtaining evaluation information regarding the position of the scan may include a linear pattern group. Furthermore, the evaluation unit may be configured to generate positional relationship evaluation information regarding the positional relationship of the multiple line scans as position evaluation information based on data collected by applying multiple line scans to the reference and standard information of the linear pattern group. The positional relationship of the multiple line scans may be, for example, the spacing between the line scans (e.g., the spacing between raster scans, the angular spacing between radial scans, etc.).

In some embodiments, the linear pattern group formed on the reference of the medical scanning device for obtaining evaluation information regarding the position of the scan may include two linear patterns parallel to each other. Furthermore, the evaluation unit may include a spacing data generation unit and a spacing evaluation information generation unit. The spacing data generation unit is configured to obtain spacing data of the two linear patterns based on data collected from the reference. The spacing evaluation information generation unit is configured to generate spacing evaluation information regarding the spacing between two line scans corresponding to the two linear patterns based on the obtained spacing data and standard information of the two linear patterns. The spacing evaluation information is an example of positional relationship evaluation information. It is clear to a person skilled in the art that the above-mentioned ophthalmic device 1 has such a configuration. According to such an embodiment, it is possible to evaluate the spacing of the line scans performed by the medical scanning device against the standard information.

In some aspects, the linear pattern group formed on the reference device of the medical scanning device for obtaining evaluation information regarding the position of the scan may include a plurality of linear patterns parallel to each other. Furthermore, the evaluation unit may include a spacing data generation unit, a spacing evaluation information generation unit, a distribution generation unit, and an overscan evaluation information generation unit. The spacing data generation unit is configured to obtain spacing data of the plurality of linear patterns based on data collected from the reference device. The spacing evaluation information generation unit is configured to generate spacing evaluation information regarding the spacing of the plurality of line scans corresponding to the plurality of linear patterns based on the obtained spacing data and standard information of the plurality of linear patterns. The distribution generation unit generates a spacing evaluation information distribution representing the distribution of the generated spacing evaluation information from the generated spacing evaluation information. The overscan evaluation information generation unit is configured to generate overscan evaluation information based on the generated spacing evaluation information distribution and the standard information of the overscan. The overscan evaluation information is an example of positional relationship evaluation information. It is clear to a person skilled in the art that the above-mentioned ophthalmic device 1 has such a configuration. According to such an aspect, it is possible to evaluate the state of overscan performed by the medical scanning device in light of the standard information.

In some aspects, the evaluation unit of the medical scanning device for obtaining evaluation information regarding the position of the scan is configured to generate repeatability evaluation information regarding the position repeatability of the repetitive scan based on a plurality of data collected by applying a repetitive scan to a reference device. The repeatability evaluation information is an example of position evaluation information. It is clear to those skilled in the art that the above-mentioned ophthalmic device 1 has such a configuration. According to such an aspect, it is possible to evaluate the position repeatability of the repetitive scan performed by the medical scanning device. For example, according to such an aspect, it is possible to perform a quality evaluation of a modality in which a repetitive scan is used, such as OCT angiography, image averaging, blood flow measurement, motion measurement, etc.

In some embodiments, the medical scanning device for obtaining evaluation information regarding the position of the scan may further include a visualization information generation unit that generates visualization information from the evaluation information generated by the evaluation unit. It will be clear to those skilled in the art that the above-mentioned ophthalmic device 1 has such a configuration. According to such an embodiment, it is possible to provide a user with visualization information that visually represents the evaluation information of the medical scanning device.

The above-described embodiments are merely examples of the implementation of this invention. Anyone who wishes to implement this invention may make any modifications (omissions, substitutions, additions, etc.) within the scope of the gist of this invention.

1 Ophthalmological equipment 500 Model eye 600 Reference device

Claims (2)

1. A model eye for acquiring evaluation information of an ophthalmic scanning device that performs pupil-based alignment with a living eye and scans the living eye to collect data,
A cornea portion corresponding to the cornea of the human eye;
an iris portion forming an opening corresponding to the pupil of a human eye;
A fundus portion having a fiducial having a periodic pattern formed thereon as a simulated fundus,
an entrance pupil of the aperture is positioned approximately 3.06 millimeters from the cornea;
The diameter of the opening is set to a value within a range of 2 to 10 millimeters,
The infrared light reflectance of the iris portion is set to a value within a range of 2.0 to 2.5 percent.
Model eye. a variable portion for changing an opening diameter of the opening formed by the iris portion,
The infrared light reflectance of the variable portion is set to a value within a range of 2.0 to 2.5 percent.
The eye model of claim 1.

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