Ophthalmic device, method for controlling ophthalmic device, and recording medium

Abstract

A Scheimpflug imaging system of an ophthalmologic device according to an exemplary embodiment is configured to satisfy the Scheimpflug condition and generates data by imaging the anterior segment of an eye being examined. An illumination system illuminates the object plane of the Scheimpflug imaging system with slit light generated using a non-monochromatic visible light source. A rotation mechanism rotates the Scheimpflug imaging system and the illumination system about a prescribed axis. A control unit controls the Scheimpflug imaging system, the illumination system, and the rotation mechanism unit so that the Scheimpflug imaging system generates a data set corresponding to a plurality of rotational positions.

Description

Ophthalmic apparatus, method for controlling an ophthalmic apparatus, and recording medium

[0001] The present disclosure relates to an ophthalmic apparatus, a method for controlling an ophthalmic apparatus, and a recording medium.

[0002] Diagnostic imaging plays an important role in the field of ophthalmology. Various types of ophthalmic devices (ophthalmic imaging devices) are used in ophthalmic diagnostic imaging, such as slit lamp microscopes, fundus cameras, scanning laser ophthalmoscopes (SLOs), and optical coherence tomography (OCT). Ophthalmic devices with imaging functions are not limited to these ophthalmic imaging devices. Ophthalmic examination and measurement devices, such as refractometers, keratometers, tonometers, specular microscopes, wavefront analyzers, and microperimeters, also have imaging functions and are used for examinations and measurements, as well as for operations such as alignment and focusing.

[0003] Although slit lamp microscopes have been widely used for observing the anterior segment of the eye, other modalities have also been proposed in recent years. For example, the ophthalmic apparatuses disclosed in U.S. Patent No. 6,286,958 (Patent Document 1) and U.S. Patent No. 7,425,068 (Patent Document 2) are configured to collect multiple images of the anterior segment of the eye by integrally rotating an illumination optical system for projecting a slit of light onto the anterior segment of the eye and a Scheimpflug camera for digitally photographing the anterior segment of the eye around an axis that is approximately aligned with the optical axis of the eye to be examined.

[0004] These known techniques utilize slit light consisting of short-wavelength visible light components (i.e., blue slit light) for anterior segment illumination, taking advantage of the fact that light scattering in the anterior segment occurs significantly at short wavelengths. On the other hand, general slit lamp microscopes have traditionally used broadband visible light, such as white light. Therefore, the appearance of images obtained by these known techniques differs from that obtained by general slit lamp microscopes, and may not be easy for experts (e.g., physicians) accustomed to images obtained by slit lamp microscopes to observe. Furthermore, comparative observation and analysis with images obtained by slit lamp microscopes may be difficult.

[0005] Various ophthalmic device systems for observing the anterior segment have been proposed, including those combining blue slit illumination, a Scheimpflug camera, and a rotary scan, as described in Patent Documents 1 and 2. For example, systems combining two non-scanning monochrome Scheimpflug cameras, systems combining a non-scanning monochrome Scheimpflug camera with a color frontal camera, and systems combining a non-scanning color Scheimpflug camera with a transillumination camera have been put to practical use. Similar to the systems described in Patent Documents 1 and 2, systems using monochrome Scheimpflug cameras suffer from the drawbacks of not being able to provide images that are easy for many specialists to observe, and of making comparisons with images obtained with slit lamp microscopes difficult. Furthermore, systems using non-scanning Scheimpflug cameras suffer from the drawbacks of not being able to capture a wide area of ​​the anterior segment, particularly the drawback of not being able to generate three-dimensional images of the anterior segment.

[0006] One object of the present disclosure is to provide ophthalmic imaging that can generate anterior segment images using a rotational scanning method similar to images obtained with a slit lamp microscope.

[0007] One exemplary aspect of an embodiment is an ophthalmic device configured to satisfy the Scheimpflug condition, and including a Scheimpflug photography system that photographs the anterior segment of a subject's eye to generate data, an illumination system that illuminates an object surface of the Scheimpflug photography system with slit light generated using a non-monochromatic visible light source, a rotation mechanism that rotates the Scheimpflug photography system and the illumination system around a predetermined axis, and a control unit that controls the Scheimpflug photography system, the illumination system, and the rotation mechanism to cause the Scheimpflug photography system to generate data sets corresponding to multiple rotational positions.

[0008] Another exemplary aspect of an embodiment is a method for controlling an ophthalmic apparatus for photographing an anterior segment of a test eye, the ophthalmic apparatus being configured to satisfy the Scheimpflug condition and including a Scheimpflug photography system that photographs the anterior segment of the test eye to generate data, an illumination system that illuminates an object surface of the Scheimpflug photography system with slit light generated using a non-monochromatic visible light source, a rotation mechanism that rotates the Scheimpflug photography system and the illumination system around a predetermined axis, a display unit, and a processor. The method of this aspect includes a step of causing the processor to control the Scheimpflug photography system, the illumination system, and the rotation mechanism to generate data sets corresponding to a plurality of rotation positions in the Scheimpflug photography system, and a step of causing the processor to control the display unit to display an image of the anterior segment based on the data sets.

[0009] Yet another exemplary aspect of the embodiment is a computer-readable non-transitory recording medium having a program recorded thereon that causes a computer to execute a method according to the exemplary aspect.

[0010] FIG. 1 is a schematic diagram illustrating a configuration of an ophthalmic apparatus according to a non-limiting aspect of an embodiment. FIG. 2 is a schematic diagram illustrating a configuration of an ophthalmic apparatus according to a non-limiting aspect of an embodiment. FIG. 3 is a schematic diagram illustrating a configuration of an ophthalmic apparatus according to a non-limiting aspect of an embodiment. FIG. 4 is a schematic diagram illustrating a configuration of an ophthalmic apparatus according to a non-limiting aspect of an embodiment. FIG. 5 is a schematic diagram illustrating a configuration of an ophthalmic apparatus according to a non-limiting aspect of an embodiment. FIG. 6 is a schematic diagram illustrating an operation of an ophthalmic apparatus according to a non-limiting aspect of an embodiment. FIG. 7 is a schematic diagram illustrating an operation of an ophthalmic apparatus according to a non-limiting aspect of an embodiment. FIG. 8 is a schematic diagram illustrating an operation of an ophthalmic apparatus according to a non-limiting aspect of an embodiment. FIG. 9 is a schematic diagram illustrating an operation of an ophthalmic apparatus according to a non-limiting aspect of an embodiment. FIG. 10 is a flowchart illustrating an operation of an ophthalmic apparatus according to a non-limiting aspect of an embodiment. FIG. 11 is a schematic diagram illustrating an operation of an ophthalmic apparatus according to a non-limiting aspect of an embodiment. 1 is a schematic diagram for explaining the operation of an ophthalmologic apparatus according to a non-limiting aspect of an embodiment.

[0011] Non-limiting embodiments of the present disclosure will now be described.

[0012] Any known technology can be combined with the embodiments. For example, any matter described in a document cited in this disclosure can be combined with any aspect of the embodiments. Furthermore, at least one of any known document related to the technical field of this disclosure, any known technology in a technical field similar to the technical field of this disclosure, and any known technology in a technical field other than the technical field of this disclosure can be combined with any aspect of the embodiments. In addition, any technical matter disclosed by the applicant of the present application regarding technology related to this disclosure (matters disclosed in patent applications, papers, etc.) can be incorporated by reference into this disclosure.

[0013] Any two or more of the various non-limiting aspects of the embodiments may be at least partially combined.

[0014] At least a portion of the various functions of the present disclosure are 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)), or a combination of these devices configured and / or programmed to perform at least some of the disclosed functions. Array), conventional circuitry, and any combination thereof. A processor is considered to be processing circuitry or circuitry, including transistors and / or other circuitry. In this disclosure, circuitry, unit, means, or similar terms refers to hardware that performs at least a portion of the disclosed functions or hardware that is programmed to perform at least a portion of the disclosed functions. The hardware may be hardware disclosed herein or known hardware that is programmed and / or configured to perform at least a portion of the described functions. In the case of a processor, where the hardware can be considered to be a type of circuitry, circuitry, unit, means, or similar terms refers to a combination of hardware and software, and the software is used to configure the hardware and / or processor.

[0015] Overview of the Embodiments One objective of the embodiments of the present disclosure is to generate anterior segment images similar to images obtained by a slit lamp microscope using a rotational scan of the anterior segment. By achieving this objective, it becomes possible to provide images that are easy to observe for specialists (e.g., physicians) who are accustomed to viewing images obtained by a slit lamp microscope, using a rotational scan of the anterior segment. It also becomes possible to perform comparative observation and analysis between images obtained by a slit lamp microscope and images obtained by a rotational scan of the anterior segment.

[0016] The objects and effects of the embodiments of the present disclosure are not limited to those described above. Although some non-limiting aspects of the embodiments are described below, those skilled in the art will understand that each of these aspects provides effects according to its characteristics (configuration, operation, action, use, etc.).

[0017] A first aspect of the embodiment is an ophthalmic apparatus capable of applying a rotational scan type anterior segment scan to an eye to be examined, comprising a Scheimpflug imaging system, an illumination system, a rotation mechanism, and a control unit. The Scheimpflug imaging system is configured to satisfy the Scheimpflug condition and is configured to image the anterior segment of the eye to be examined and generate data. The illumination system is configured to illuminate an object plane of the Scheimpflug imaging system with slit light generated using a non-monochromatic visible light source. The rotation mechanism is configured to rotate the Scheimpflug imaging system and the illumination system around a predetermined axis. The control unit is configured to control the Scheimpflug imaging system, the illumination system, and the rotation mechanism to cause the Scheimpflug imaging system to generate data sets corresponding to multiple rotation positions.

[0018] The Scheimpflug condition is a condition for an optical system (in this disclosure, an imaging system) that stipulates that the optical system be configured so that the object plane, the lens principal plane, and the film plane (image capture plane) intersect on the same straight line. In an optical system that satisfies the Scheimpflug condition, the object plane is not arranged parallel to the lens principal plane. A camera using such a Scheimpflug optical system (a Scheimpflug camera) can simultaneously focus and capture images over a wide depth range, from close to far distances. In the anterior eye segment scan disclosed herein, for example, images can be captured while being focused over a wide depth range, from the anterior surface of the cornea to the posterior surface of the lens. This advantageously enables the acquisition of high-resolution images that capture the entire main observation area of ​​the anterior eye segment.

[0019] The ophthalmic apparatus according to the first aspect is configured to perform a rotational scan of the anterior segment using slit light generated using a non-monochromatic visible light source, thereby enabling the generation of an anterior segment image similar in appearance to an image obtained by a slit lamp microscope. Furthermore, the ophthalmic apparatus according to the first aspect is configured to perform a rotational scan of the anterior segment using a Scheimpflug imaging system, thereby enabling the generation of an image with a deep depth of field. Therefore, the ophthalmic apparatus according to the first aspect is capable of generating an anterior segment image with a deep depth of field that faithfully reproduces the appearance of an image obtained by a slit lamp microscope by the rotational scan of the anterior segment.

[0020] A second aspect of the embodiment is the ophthalmic device of the first aspect, wherein the non-monochromatic visible light source includes a white light source.

[0021] A third aspect of the embodiment is the ophthalmologic apparatus of the second aspect, wherein the Scheimpflug imaging system is configured to generate data including RGB information.

[0022] A fourth aspect of the embodiment is the ophthalmic apparatus according to any one of the first to third aspects, wherein the non-monochromatic visible light source includes a wavelength swept light source.

[0023] A fifth aspect of the embodiment is an ophthalmic device of the fourth aspect, wherein the swept light source is configured to sweep wavelengths across a visible wavelength band, and the Scheimpflug imaging system is configured to generate data including RGB information.

[0024] A sixth aspect of the embodiment is the ophthalmologic apparatus of any one of the first to fifth aspects, including a first Scheimpflug imaging system, a first illumination system, a second Scheimpflug imaging system, and a second illumination system. The first Scheimpflug imaging system is configured to satisfy the Scheimpflug condition and to capture an image of an anterior segment of an eye to be examined to generate first data. The first illumination system is configured to illuminate an object surface of the first Scheimpflug imaging system with a first slit light beam generated using a first non-monochromatic visible light source. The second Scheimpflug imaging system is configured to satisfy the Scheimpflug condition and to capture an image of an anterior segment of the eye to be examined to generate second data. The second illumination system is configured to illuminate an object surface of the second Scheimpflug imaging system with a second slit light beam generated using a second non-monochromatic visible light source.

[0025] A seventh aspect of the embodiment is the ophthalmologic apparatus according to any one of the first to sixth aspects, further including a fixation optical system that presents a fixation target to the subject's eye.

[0026] An eighth aspect of the embodiment is an ophthalmic device of the seventh aspect, wherein the fixation optical system is configured to project fixation light having an intensity higher than that of the slit light onto the subject's eye so as to present a first fixation target positioned within the exit pupil of the illumination system to the subject's eye.

[0027] A ninth aspect of the embodiment is an ophthalmic device of the seventh or eighth aspect, wherein the fixation optical system is configured to project fixation light onto the subject's eye so as to present a large-sized second fixation target positioned within the exit pupil of the illumination system to the subject's eye.

[0028] A tenth aspect of the embodiment is an ophthalmic device according to any one of the seventh to ninth aspects, wherein the fixation optical system is configured to project fixation light onto the subject's eye so as to present the subject's eye with a third fixation target, at least a portion of which changes, located within the exit pupil of the illumination system.

[0029] An eleventh aspect of the embodiment is an ophthalmic device according to any one of the seventh to tenth aspects, wherein the fixation optical system is configured to present a black fourth fixation target positioned within the exit pupil of the illumination system to the subject's eye.

[0030] A twelfth aspect of the embodiment is the ophthalmic apparatus of any one of the seventh to eleventh aspects, further including a housing for an illumination system. The housing for the illumination system is provided with a notch or a light-transmitting portion outside an exit pupil of the illumination system. The fixation optical system is configured to project fixation light onto the subject's eye through the notch or the light-transmitting portion so as to present a fifth fixation target positioned outside the exit pupil of the illumination system to the subject's eye.

[0031] A thirteenth aspect of the embodiment is an ophthalmic device according to any one of the first to twelfth aspects, wherein the angle between the optical axis of the illumination system and a plane perpendicular to the optical axis of the Scheimpflug photography system is in the range of 0 to 90 degrees, preferably in the range of 30 to 60 degrees, and more preferably in the range of 35 to 53 degrees.

[0032] In a fourteenth aspect of the embodiment, in the ophthalmologic apparatus according to any one of the first to thirteenth aspects, the Scheimpflug photography system includes an image sensor. The image sensor is disposed eccentrically with respect to the optical axis of the Scheimpflug photography system.

[0033] In a fifteenth aspect of the embodiment, in the ophthalmic apparatus of the fourteenth aspect, the image sensor includes a photodetector array and a microlens array configured as an imaging lens group for the photodetector array, and the image sensor is disposed eccentrically with respect to the optical axis of the Scheimpflug imaging system so that an angle formed between the optical axis of the microlens array and light rays guided to the microlens array by the Scheimpflug imaging system is small.

[0034] A sixteenth aspect of the embodiment is an ophthalmic device according to the fourteenth or fifteenth aspect, wherein the center position of the light receiving surface of the image sensor is located away from the intersection of the optical axis of the Scheimpflug imaging system and the image plane.

[0035] A seventeenth aspect of the embodiment is an ophthalmic device according to any one of the fourteenth to sixteenth aspects, wherein the center position of the light receiving surface of the image sensor is located closer to the optical axis of the illumination system than the intersection of the optical axis of the Scheimpflug photography system and the image plane.

[0036] Any two or more of the features of the first to seventeenth aspects may be at least partially combined. Also, any feature described in the present disclosure may be at least partially combined with the first to seventeenth aspects. An ophthalmic device of an aspect obtained by such a combination exhibits the effects based on each of the combined features, as well as the synergistic effects of the two or more combined features.

[0037] An eighteenth aspect of the embodiment provides a method corresponding to the ophthalmic apparatus of the first aspect. The method of this aspect is a method for controlling an ophthalmic apparatus for photographing an anterior segment of an eye to be examined. The ophthalmic apparatus controlled by the method of this aspect includes a Scheimpflug photography system, an illumination system, a rotation mechanism, a display, and a processor. The Scheimpflug photography system is configured to satisfy the Scheimpflug condition and is configured to photograph the anterior segment of the eye to be examined and generate data. The illumination system is configured to illuminate an object plane of the Scheimpflug photography system with slit light generated using a non-monochromatic visible light source. The rotation mechanism is configured to rotate the Scheimpflug photography system and the illumination system around a predetermined axis.

[0038] The method of this aspect causes the processor to execute control of the Scheimpflug imaging system, the illumination system, and the rotation mechanism unit to generate data sets corresponding to a plurality of rotation positions in the Scheimpflug imaging system, and further causes the processor to execute control to display images of the anterior segment based on the generated data sets on the display unit.

[0039] The method according to the eighteenth aspect provides the same effects as the ophthalmic apparatus according to the first aspect.

[0040] Any of the features of the first to seventeenth aspects can be at least partially combined with the method of the eighteenth aspect. Also, any of the features described in this disclosure can be at least partially combined with the method of the eighteenth aspect. The method of the aspect obtained by such a combination exhibits the effects of each of the combined features, as well as the synergistic effects of two or more of the combined features.

[0041] A nineteenth aspect of the embodiment is a program for causing a computer to execute the method of the eighteenth aspect. The computer of the nineteenth aspect includes the processor of the eighteenth aspect.

[0042] The program according to the nineteenth aspect provides the same effects as the ophthalmologic apparatus according to the first aspect.

[0043] Any of the features of the first to seventeenth aspects can be at least partially combined with the program according to the nineteenth aspect. Furthermore, any of the features described in the present disclosure can be at least partially combined with the program according to the nineteenth aspect. The program according to the aspect obtained by such a combination not only exhibits the effects based on each of the combined features, but also exhibits a synergistic effect of the two or more combined features.

[0044] A twentieth aspect of the embodiment is a computer-readable non-transitory recording medium having the program of the nineteenth aspect recorded thereon.

[0045] The recording medium according to the twentieth aspect has the same effects as the ophthalmologic apparatus according to the first aspect.

[0046] Any of the features of the first to seventeenth aspects can be at least partially combined into a recording medium according to the twentieth aspect. Furthermore, any of the features described in the present disclosure can be at least partially combined into a recording medium according to the twentieth aspect. A recording medium according to an aspect obtained by such a combination will not only exhibit the effects based on each of the combined features, but will also exhibit a synergistic effect of the two or more combined features.

[0047] This disclosure describes various non-limiting aspects, including aspects 1 to 20. This disclosure mainly describes exemplary aspects of an ophthalmic device, exemplary aspects of a method for controlling an ophthalmic device, exemplary aspects of a program, and exemplary aspects of a recording medium. However, it will be understood by those skilled in the art that possible categories of aspects of embodiments are not limited to these.

[0048] <Ophthalmic Apparatus> Several non-limiting examples of aspects of the ophthalmic apparatus according to the embodiment will be described below. The ophthalmic apparatus according to the embodiment includes a rotary type anterior segment scanner similar to those disclosed in Patent Documents 1 and 2.

[0049] 1 shows an example of the configuration of an ophthalmic apparatus according to one embodiment. The ophthalmic apparatus 1 of this embodiment is used for imaging the anterior segment of a subject's eye E, and includes an illumination and imaging optical system 2, a fixation optical system 3, a movement mechanism 6, a control unit 7, a data processing unit 8, a communication unit 9, and a user interface (UI) 10. The cornea of ​​the subject's eye E is indicated by the symbol Co, the iris by the symbol Ir, and the crystalline lens by the symbol Cr.

[0050] According to the convention in the field of ophthalmology, the direction along the axis of the subject's eye E is defined as the Z direction (Z axis), and the plane perpendicular to the Z direction is defined as the XY plane. The left-right direction (horizontal direction) for the subject is defined as the X direction (X axis), and the direction perpendicular to both the X and Z directions (up-down direction, body axis direction) is defined as the Y direction (Y axis).

[0051] Reference symbol 2a denotes the optical axis of the illumination and photography optical system 2. The optical axis 2a of the illumination and photography optical system 2 (in this embodiment, the illumination optical axis 21a shown in FIG. 2) is disposed substantially parallel to the Z axis. Reference symbol 3a denotes the optical axis of the fixation optical system 3 (referred to as the fixation optical axis). The fixation optical axis 3a is disposed so as to be inclined at an angle α with respect to the Z axis (illumination optical axis 21a). The angle α is referred to as the fixation angle. The magnitude of the fixation angle α is a non-negative value, i.e., zero or a positive value.

[0052] In an embodiment in which the fixation angle α=0 is applied, the fixation optical system 3 is an optical system arranged coaxially with the illumination and photography optical system 2, and presents a fixation target to the subject's eye E that is coaxial with the light (slit light) projected onto the subject's eye E by the illumination and photography optical system 2. In this embodiment, the optical path of the Scheimpflug optical system and the optical path of the fixation optical system are coaxially coupled by an optical path coupling element. This optical path coupling element may be, for example, a half mirror or a dichroic mirror.

[0053] In a mode in which a fixation angle α>0 is applied, the fixation optical system 3 presents a fixation target to the subject's eye E from a direction inclined with respect to the optical axis 2a (Z-axis) of the illumination and photography optical system 2. This inclined direction may be determined arbitrarily or may be variable.

[0054] The moving mechanism 6 moves the illumination and photography optical system 2 and the fixation optical system 3. The moving mechanism 6 may be capable of moving the illumination and photography optical system 2 and the fixation optical system 3 three-dimensionally (i.e., in the X, Y, and Z directions). This three-dimensional movement is used for alignment and tracking. The moving mechanism 6 also rotates the illumination and photography optical system 2 in order to apply a rotational scan type anterior eye segment scan to the subject's eye E. Details of the moving mechanism 6 will be described later.

[0055] The control unit 7 is configured to control each unit of the ophthalmologic apparatus 1. For example, the control unit 7 controls the illumination and photography optical system 2 (illumination light source, image sensor, optical element, mechanism, etc.), the fixation optical system 3 (fixation light source, etc.), the movement mechanism 6, the data processing unit 8, the communication unit 9, the user interface 10, etc.

[0056] The control unit 7 includes a processor, a main storage device, an auxiliary storage device, etc. Computer programs such as various control programs are stored in the auxiliary storage device. These computer programs may be stored in a computer or storage device accessible to the ophthalmic apparatus 1. The functions of the control unit 7 are realized by cooperation between software such as the control programs and hardware such as the processor.

[0057] The data processing unit 8 executes various types of data processing. The data to be processed may be either data acquired by the ophthalmologic apparatus 1 or data input from an external source.

[0058] The data processing unit 8 includes a processor, a main storage device, an auxiliary storage device, etc. Computer programs such as various data processing programs are stored in the auxiliary storage device. These computer programs may be stored in a computer or storage device accessible to the ophthalmic apparatus 1. The functions of the data processing unit 8 are realized by cooperation between software such as the data processing programs and hardware such as the processor.

[0059] The communication unit 9 performs data communication between the ophthalmic apparatus 1 and other devices. The method of this data communication may be determined arbitrarily and may be wired communication or wireless communication. The transmitted data and received data may be encrypted data. In this case, the ophthalmic apparatus 1 (for example, the control unit 7 or the data processing unit 8) includes a processor capable of performing encryption and decryption.

[0060] The user interface 10 includes any user interface device such as a display device or an operation device. A user such as a doctor, a patient, or an assistant can use the user interface 10 to operate the ophthalmic apparatus 1 or input information to the ophthalmic apparatus 1. At least a part of the user interface 10 may be a peripheral device of the ophthalmic apparatus 1.

[0061] The user interface 10 of this embodiment includes a display unit 11 shown in Fig. 3. The display unit 11 displays various information under the control of the control unit 7. The display unit 11 may include a flat panel display such as a liquid crystal display (LCD).

[0062] The user interface 10 may include an operation device (not shown). The operation device includes a device for operating the ophthalmic apparatus 1 and a device for inputting information. For example, the operation device includes a button, a switch, a lever, a dial, a handle, a knob, a mouse, a keyboard, a trackball, an operation panel, etc. The user interface 10 may include a device in which a display device and an operation device are integrated, such as a touch screen.

[0063] The illumination and photography optical system 2 includes an imaging system (Scheimpflug imaging system) configured to satisfy the Scheimpflug condition and an illumination system that illuminates the object plane of this Scheimpflug imaging system, and is capable of performing Scheimpflug imaging of the anterior segment of the subject's eye E. The illumination and photography optical system 2 is used to apply an anterior segment scan to the subject's eye E to collect a data set consisting of multiple anterior segment images (anterior segment image set, anterior segment image group). The anterior segment scan method is a rotational scan similar to those described in Patent Documents 1 and 2.

[0064] The illumination light used for scanning the anterior eye segment in this embodiment is slit light. This slit light is generated from light emitted by a non-monochromatic visible light source 13 shown in Fig. 3. The non-monochromatic visible light source 13 may be a component of the ophthalmic apparatus 1 (the illumination and photography optical system 2, the illumination system 21) or an external device connected to the ophthalmic apparatus 1.

[0065] The non-monochromatic visible light source 13 is a light source that outputs visible light with a wavelength band wider than that of monochromatic visible light. For example, the light (non-monochromatic visible light) generated by the non-monochromatic visible light source 13 has a wavelength band wider than that of the short wavelength component (blue monochromatic light) used in Patent Documents 1 and 2. The wavelength band of the blue monochromatic light may be, but is not limited to, typically about 380 to 500 nanometers.

[0066] Non-limiting examples of light source devices that can be used as the non-monochromatic visible light source 13 include a white light source, a broadband visible light source, and a wavelength-swept visible light source. In some embodiments, the non-monochromatic visible light source 13 includes a light-emitting device that generates first non-monochromatic visible light and a bandpass filter that extracts second non-monochromatic visible light having a narrower wavelength band than the first non-monochromatic visible light from the first non-monochromatic visible light. In this case, the slit light is generated from the second non-monochromatic visible light. In embodiments that do not include a bandpass filter, the slit light is generated from the non-monochromatic visible light (corresponding to the first non-monochromatic visible light) generated by the non-monochromatic visible light source 13 (light-emitting device).

[0067] Fig. 2 shows an example of the illumination and photography optical system 2. The optical axis 2a of the illumination and photography optical system 2 shown in Fig. 1 corresponds to the illumination optical axis 21a shown in Fig. 2. The illumination and photography optical system 2 of this example includes an illumination system 21 and a Scheimpflug photography system 22.

[0068] Some embodiments may include two or more Scheimpflug imaging systems. For example, as described in Japanese Patent No. 7466607, a pair of Scheimpflug imaging systems may be provided that capture images from opposite directions. The two or more Scheimpflug imaging systems have a common object plane, and this common object plane is illuminated by the illumination system.

[0069] The illumination system 21 is configured to project illumination light (non-monochromatic visible illumination light, non-monochromatic visible slit light) onto the anterior segment of the subject's eye E based on the non-monochromatic visible light generated by the non-monochromatic visible light source 13. The non-monochromatic visible slit light is projected onto the object plane of the Scheimpflug photography system 22. In this way, the illumination and photography optical system 2 is configured to apply Scheimpflug photography to the anterior segment illuminated with non-monochromatic visible slit light.

[0070] In some embodiments, the illumination system 21 includes a non-monochromatic visible light source 13 that generates non-monochromatic visible light, a slit forming unit that forms a slit opening for converting the non-monochromatic visible light into slit light (non-monochromatic visible slit light), and an optical system (such as an objective lens) that projects the non-monochromatic visible slit light onto the subject's eye E. The illumination system 21 may be configured so that the dimensions (slit width, slit length) and orientation of the slit opening are variable.

[0071] In some embodiments, the Scheimpflug imaging system 22 includes an optical system including an objective lens, a variable magnification optical system, and an imaging lens, and an image sensor that detects light guided by the optical system. The image sensor is an area image sensor having a light receiving surface (imaging surface) formed by a two-dimensionally arranged array of photodetector elements, and may be, for example, a CCD image sensor or a CMOS image sensor.

[0072] The illumination system 21 and the Scheimpflug photography system 22 are moved by a movement mechanism 6. As shown in Fig. 3, the movement mechanism 6 includes a parallel movement mechanism 61 and a rotation mechanism 62. Although not shown, the movement mechanism 6 may also include a mechanism for performing a tilting action to rotate the illumination and photography optical system 2 up and down, or a swinging action to rotate it left and right.

[0073] The parallel movement mechanism 61 is configured to translate the illumination and photography optical system 2 three-dimensionally, and is used for alignment of the illumination and photography optical system 2 with respect to the eye E to be examined.

[0074] The rotation mechanism 62 is configured to rotate the illumination and photographing optical system 2 about a predetermined axis. The rotation mechanism 62 integrally rotates the illumination system 21 and the Scheimpflug photographing system 22 in an anterior eye segment scan using non-monochromatic visible slit light. The rotation axis in this anterior eye segment scan may be, for example, the optical axis 21a (illumination optical axis) of the illumination system 21. By combining the operations of the illumination system 21, the Scheimpflug photographing system 22, and the rotation mechanism 62, anterior eye segment scan using a rotational scan method using non-monochromatic visible slit light is realized.

[0075] In addition to the rotational scanning type anterior eye segment scan using the rotation mechanism 62, the ophthalmologic apparatus 1 of this embodiment may be capable of performing translational scanning type anterior eye segment scan using the translation mechanism 61. For example, translational scanning type anterior eye segment scan can be performed by moving a slit light beam with the Y direction as the longitudinal direction in the X direction.

[0076] The angle formed by the illumination optical axis 21a of the illumination system 21 and the optical axis (photography optical axis) 22a of the Scheimpflug photography system 22 is called the Scheimpflug angle. The magnitude of the Scheimpflug angle is called the Scheimpflug angle θ. The Scheimpflug angle θ may be determined arbitrarily.

[0077] 4 shows a non-limiting example configuration of the illumination system 21 and the Scheimpflug photography system 22. The illumination system 21 projects a non-monochromatic visible slit light beam 21b onto the subject's eye E. The Scheimpflug photography system 22 photographs the anterior segment of the subject's eye E onto which the non-monochromatic visible slit light beam 21b is projected. The Scheimpflug photography system 22 includes an image sensor 221. The imaging surface of the image sensor 221 is arranged on an image plane 221P of the Scheimpflug photography system 22.

[0078] The imaging light beam group 22b indicates the range of the field of view (range in the Z direction) of the Scheimpflug imaging system 22. The Scheimpflug imaging system 22 in this example is designed so that the field of view includes the range from the anterior surface of the cornea to the posterior surface of the lens.

[0079] Two planes perpendicular to the imaging optical axis 22a are denoted by reference numerals 22P1 and 22P2. The perpendicular plane 22P1 is located at a position passing through an intersection C1 between the illumination optical axis 21a and the imaging optical axis 22a. The perpendicular plane 22P2 is located at a position passing through an intersection C2 between the imaging optical axis 22a and the image plane 221P.

[0080] 4, the Scheimpflug angle formed by the illumination optical axis 21a and the photographing optical axis 22a and the angle formed by the illumination optical axis 21a and the vertical plane 22P1 are complementary to each other. In other words, the sum of the Scheimpflug angle and the angle formed by the illumination optical axis 21a and the vertical plane 22P1 is a right angle.

[0081] In some embodiments, the angle between the illumination optical axis 21a and the vertical plane 22P1 may be any value in the range of 0 to 90 degrees. In other words, the Scheimpflug angle θ may be any value in the range of 0 to 90 degrees. In this case, for example, Scheimpflug photography can be applied to at least a shallow region of the anterior segment. In some specific examples, Scheimpflug photography can be applied to a region including at least the cornea and its vicinity.

[0082] In some embodiments, the angle between the illumination optical axis 21a and the vertical plane 22P1 may be any value within the range of 30 degrees to 60 degrees. In other words, the Scheimpflug angle θ may be any value within the range of 30 degrees to 60 degrees. In this case, for example, Scheimpflug photography can be applied to shallow to slightly deep regions of the anterior segment. In some specific examples, Scheimpflug photography can be applied to a region including at least the anterior surface of the cornea and the anterior chamber.

[0083] In some embodiments, the angle between the illumination optical axis 21a and the vertical plane 22P1 may be any value within the range of 35 degrees to 53 degrees. In other words, the Scheimpflug angle θ may be any value within the range of 37 degrees to 55 degrees. In this case, for example, Scheimpflug photography can be applied to a wide range of the anterior segment of the eye, from shallow to deep regions. In some specific examples, Scheimpflug photography can be applied to a range from the anterior surface of the cornea to the posterior surface of the lens.

[0084] Although the case where the Scheimpflug angle θ is selected in consideration of the size of the imaging range has been described above, other factors may also be considered. For example, the Scheimpflug angle θ may be determined by considering at least one of various factors related to Scheimpflug imaging, such as the size of the imaging range, the brightness of the illumination, the characteristics of the optical elements, the level of image quality (the difficulty of image quality correction), and the level of trapezoidal distortion (the difficulty of trapezoidal correction). The same applies to other design values.

[0085] In this example, the image sensor 221 is disposed eccentrically with respect to the imaging optical axis 22a. In a typical Scheimpflug optical system, the center position of the light receiving surface of the image sensor is disposed on the imaging optical axis. In contrast, in this example, the center position 221x of the light receiving surface of the image sensor 221 is disposed at a position away from the imaging optical axis 22a. More specifically, the center position 221x of the light receiving surface of the image sensor 221 is disposed at a position away from the intersection C2 of the imaging optical axis 22a and the image plane 221P. The light receiving surface of the image sensor 221 is disposed on the image plane 221P. In other words, the displacement of the image sensor 221 is performed along the image plane 221P (on the image plane 221P).

[0086] FIG. 5 shows an example of the configuration of the image sensor 221 shown in FIG. 4 . Similar to a typical color image sensor, the image sensor 221 of this example includes a microlens array 221a, a color filter array 221b, and a photodetector array 221c. The photodetector array 221c is an optical device in which a large number of photodiodes are arranged. The microlens array 221a is an optical device in which a large number of microlenses that act as imaging lenses corresponding to the photodiodes of the photodetector array 221c are arranged. The color filter array 221b is an optical device in which a group of color filters (a group of red (R) filters, a group of green (G) filters, and a group of blue (B) filters) corresponding to the photodiodes of the photodetector array 221c are arranged.

[0087] In some embodiments, as shown in FIG. 5 , the image sensor 221 is disposed eccentrically with respect to the imaging optical axis 22a so that the angle (referred to as the imaging light ray incident angle β) between the light rays (imaging light ray 22c) guided by the imaging system 2 to the photodetector array 221c (imaging surface, light receiving surface) and the optical axis 221d of the microlens array 221a is smaller than the angle in a conventional configuration (i.e., a configuration in which the center position of the light receiving surface of the image sensor is located on the imaging optical axis). The imaging light ray incident angle β may be determined arbitrarily and is preferably 30 degrees or less, more preferably 10 degrees or less. Note that the optical axis of each microlens in the microlens array 221a is oriented in a uniform direction. In other words, the optical axes of each microlens in the microlens array 221a are parallel. The orientation of the optical axis 221d corresponds to the orientation of these optical axes.

[0088] 6, the image sensor 221 is disposed eccentrically with respect to the imaging optical axis 22a so that the angle formed between the imaging light ray 22c guided to the microlens array 221a by the imaging system 2 and the optical axis 221d of the microlens array 221a (referred to as the imaging light incident angle γ) is smaller than that in a conventional configuration. The imaging light incident angle γ may be determined arbitrarily.

[0089] In addition, in the example of Figure 4, the center position 221x of the light receiving surface of the image sensor 221 is located at a position offset toward the illumination system 2 (a position closer to the illumination optical axis 21a) with respect to the intersection C2 of the imaging optical axis 22a and the image plane 221P.

[0090] In some embodiments, by adopting a configuration in which the image sensor 221 is disposed eccentrically with respect to the imaging optical axis 22a, the imaging light ray 22c can be directed at an angle of 90 degrees or close to that with respect to the light receiving surface of the image sensor 221. In other words, the imaging light ray 22c can be directed parallel to or close to the optical axis 221d of the image sensor 221. This makes it possible to improve the light receiving efficiency of the image sensor 221.

[0091] The decentering amount Δ of the image sensor 221 shown in FIG. 4 is the offset of the center position 221x of the light receiving surface of the image sensor 221 from the intersection C2 of the imaging optical axis 22a and the image plane 221P. The decentering amount Δ may be determined based on any parameters or characteristics. Non-limiting examples of factors that can be referenced for determining the decentering amount Δ include the imaging light incident angle (β, γ), the position of the entrance pupil of the Scheimpflug imaging system 22, and the target value of resolution.

[0092] Next, we will explain the fixation optical system 3. In this embodiment, the anterior segment is scanned by rotating the non-monochromatic visible slit light 21b that is clearly visible to the human eye, and this anterior segment scanning itself can be a factor that destabilizes the fixation state of the subject's eye E. Therefore, in this embodiment, it is desirable to introduce a means for stabilizing the fixation state of the subject's eye E during the anterior segment scanning.

[0093] The fixation optical system 3 is configured to present a fixation target to the subject's eye E. The fixation optical system 3 may have a general configuration. In some embodiments, the fixation optical system 3 may include a fixation light source, a diffuser, a pinhole member, a first lens, a cross reticle plate, and a second lens, according to the non-limiting configuration example described in Japanese Patent Application Laid-Open No. 2023-49320. The fixation light source generates visible light (e.g., green light). The generated visible light is diffused by the diffuser and then projected onto the pinhole member. The visible light that passes through an opening (pinhole) formed in the pinhole member is projected onto the cross reticle plate via the first lens. The visible light that passes through a cross-shaped light-transmitting portion formed in the cross reticle plate is guided to the subject's eye E via the second lens. The subject can visually recognize the cross-shaped fixation target.

[0094] The following describes some non-limiting examples of the fixation optical system 3 that can be applied to the ophthalmic apparatus 1 of this embodiment. Two or more of these non-limiting examples can be at least partially combined.

[0095] The first example of the fixation optical system 3 improves the visibility of the fixation target and stabilizes the fixation state of the subject's eye E during an anterior segment scan by presenting high-intensity fixation light (bright fixation light) to the subject's eye E in parallel with an anterior segment scan using non-monochromatic visible slit light. The presented fixation target may be dynamic or static. A dynamic fixation target is a fixation target whose appearance (intensity (brightness), size, shape, color, etc.) and position are variable, while a static fixation target is a fixation target whose appearance and position are unchanged.

[0096] 7, the fixation optical system 3 of this example is configured to project fixation light having an intensity higher than that of the non-monochromatic visible slit light 21b onto the subject's eye E so as to present a fixation target 31 that is (apparently) located within the exit pupil 21c of the illumination system 21 as viewed from the subject's eye E to the subject's eye E. The fixation target 31 is presented to the subject's eye E while an anterior segment scan is being performed by the rotational scan method using the non-monochromatic visible slit light 21b.

[0097] The intensity of the fixation light may be determined arbitrarily. For example, based on the brightness of the image of the non-monochromatic visible slit light 21 b visually recognized by the subject's eye E, a high-intensity fixation light may be used to make the subject's eye E visually recognize a fixation target 31 that is brighter than the brightness of the image of the non-monochromatic visible slit light 21 b.

[0098] The wavelength band of the fixation light may be determined arbitrarily. The wavelength band of the fixation light may be at least partially different from the wavelength band of the non-monochromatic visible slit light 21b. In some embodiments, a portion of the wavelength band of visible light may be used for the non-monochromatic visible slit light 21b, and another portion of the wavelength band of visible light may be used for the fixation light. In some embodiments, the entire wavelength band of visible light may be used for the non-monochromatic visible slit light 21b, and a wavelength band of visible light with high visibility to the human eye (e.g., a wavelength band corresponding to green) may be used for the fixation light.

[0099] The second example of the fixation optical system 3 is to present a large fixation target to the subject's eye E in parallel with an anterior segment scan using a non-monochromatic visible slit light, thereby improving the visibility of the fixation target and stabilizing the fixation state of the subject's eye E during an anterior segment scan. The presented fixation target may be either dynamic or static.

[0100] 8 or 9, the fixation optical system 3 of this example is configured to project fixation light onto the subject's eye E so as to present to the subject's eye E a large fixation target 32A or 32B that is (apparently) located within the exit pupil 21c of the illumination system 21 as viewed from the subject's eye E. The fixation target 32A or 32B is presented to the subject's eye E while an anterior segment scan is being performed by a rotational scan method using the non-monochromatic visible slit light 21b.

[0101] The size of the fixation light may be determined arbitrarily. For example, based on the size of the image of the non-monochromatic visible slit light 21b visually recognized by the subject's eye E, fixation light may be used that causes the subject's eye E to visually recognize a fixation target 32A or 32B that is larger than the size of the image of the non-monochromatic visible slit light 21b. As in the first example, the wavelength band of the fixation light may be determined arbitrarily.

[0102] 8, a fixation light for forming an X-shaped (cross-shaped) fixation target 32A is projected together with the non-monochromatic visible slit light 21b onto the subject's eye E. The subject is prompted to gaze at, for example, the center position of the fixation target 32A (the intersection position of the two lines forming the X shape) or at an end position of the fixation target 32A.

[0103] 9, a fixation light for forming a circular fixation target 32B is projected together with the non-monochromatic visible slit light 21b onto the subject's eye E. The subject is prompted to gaze at, for example, an arbitrary position (e.g., the upper end position) of the fixation target 32B or at the center position of the fixation target 32B.

[0104] The fixation target 32A in FIG. 8 and the fixation target 32B in FIG. 9 are non-limiting examples, and the size, shape, position, etc. of the fixation target presented to the subject's eye E are not limited to these.

[0105] A third example of the fixation optical system 3 improves the visibility of the fixation target and stabilizes the fixation state of the test eye E during an anterior segment scan by presenting a dynamic fixation target to the test eye E in parallel with an anterior segment scan using non-monochromatic visible slit light.

[0106] As shown in Fig. 10 , the fixation optical system 3 of this example is configured to project fixation light onto the subject's eye E so as to present dynamic fixation targets 33A and 33B, which are (apparently) located within the exit pupil 21c of the illumination system 21 as viewed from the subject's eye E, to the subject's eye E. At least a portion of the dynamic fixation targets 33A and 33B is variable. The change in the fixation target shown in Fig. 10 (from fixation target 33A to fixation target 33B) is merely a non-limiting example. The dynamic fixation target 33A (33B) is presented to the subject's eye E while an anterior segment scan is being performed using a rotational scan method using the non-monochromatic visible slit light 21b.

[0107] The change in the fixation target may be any change, such as a change in intensity (brightness), a change in size, a change in shape, a change in color, or a change in position, or a combination of two or more of these. The manner of the change in the fixation target may be any change, such as a single change, multiple changes, repeated changes (e.g., blinking), continuous changes, or gradual changes. The change in the fixation target is realized by the control unit 7 controlling the fixation optical system 3.

[0108] The fourth example of the fixation optical system 3 presents a black fixation target to the subject's eye E in parallel with an anterior segment scan using a non-monochromatic visible slit light, thereby improving the visibility of the fixation target and stabilizing the fixation state of the subject's eye E during the anterior segment scan. The presented black fixation target may be dynamic or static. The dimensions and presentation position of the black fixation target may be determined arbitrarily.

[0109] 11 , the fixation optical system 3 of this example is configured to present a black fixation target 34 to the subject's eye E, which is (apparently) located within the exit pupil 21c of the illumination system 21 as viewed from the subject's eye E. The black fixation target 34 is presented to the subject's eye E, for example, by placing a black dot in the optical path of the illumination system 21. The black fixation target 34 is presented to the subject's eye E while an anterior segment scan is being performed by a rotational scan method using the non-monochromatic visible slit light 21b.

[0110] The fifth example of the fixation optical system 3 presents a fixation target located outside the exit pupil 21c of the illumination system 21 to the subject's eye E in parallel with an anterior segment scan using non-monochromatic visible slit light, thereby improving the visibility of the fixation target and stabilizing the fixation state of the subject's eye E during an anterior segment scan. The presented fixation target may be dynamic or static. The brightness and dimensions of the fixation target may be determined arbitrarily.

[0111] 12 , a cutout or light-transmitting portion for passing fixation light is formed in the housing 21d of the illumination system 21. The cutout or light-transmitting portion is provided outside the exit pupil 21c of the illumination system 21. The fixation optical system 3 is configured to project fixation light onto the subject's eye E through the cutout or light-transmitting portion of the housing 21d so as to present a fixation target 35 (apparently) located outside the exit pupil 21c of the illumination system 21 to the subject's eye E. The fixation target 35 is presented to the subject's eye E while an anterior segment scan is being performed by the rotational scan method using the non-monochromatic visible slit light 21b.

[0112] Next, a description will be given of the operation of the ophthalmologic apparatus 1. Fig. 13 shows a non-limiting example of the operation.

[0113] First, the subject's head is placed on a holder (forehead rest, chin rest) (not shown) of the ophthalmic apparatus 1. In response to an instruction operation performed using, for example, the user interface 10, the ophthalmic apparatus 1 starts projecting fixation light onto the subject's eye E, which is the target of an anterior eye scan, and aligns the illumination and imaging optical system 2 with the subject's eye E (S1).

[0114] After the alignment is completed, the ophthalmologic apparatus 1 may start tracking to make the illumination and photographing optical system 2 follow the movement of the subject's eye E.

[0115] Alignment and tracking may be performed using an anterior segment observation system (not shown). The anterior segment observation system acquires an observation image (moving image) of the anterior segment of the subject's eye E. The observation image is typically an image of the anterior segment captured from the front, and may be a color image or a near-infrared image. For details of the anterior segment observation system, see, for example, Japanese Patent No. 7517903.

[0116] After the preparatory operations such as alignment are completed, the ophthalmologic apparatus 1 projects non-monochromatic visible slit light 21b onto the anterior segment of the subject's eye E using the illumination system 21 (S2).

[0117] The initial position (initial orientation) of the non-monochromatic visible slit light 21b may be determined arbitrarily. For example, the longitudinal direction of the non-monochromatic visible slit light 21b is approximately aligned with the Y direction, and the center (the center in the longitudinal direction and the center in the lateral direction) of the non-monochromatic visible slit light 21b is approximately aligned with the axis of the subject's eye E. In this embodiment, the center of the non-monochromatic visible slit light 21b corresponds to the illumination optical axis 21a of the illumination system 21.

[0118] Next, the anterior segment of the eye E is scanned by a rotational scan method using the non-monochromatic visible slit light 21b (S3).

[0119] The anterior eye segment scan in this example is performed by the control unit 7 controlling the illumination system 21, the Scheimpflug photography system 22, and the rotation mechanism 62. More specifically, the control unit 7 controls the illumination system 21 to output non-monochromatic visible slit light 21b, controls the Scheimpflug photography system 22 to repeat photography (data generation) at predetermined time intervals (predetermined photography rate), and controls the rotation mechanism 62 to rotate the illumination system 21 and the Scheimpflug photography system 22 integrally around the illumination optical axis 21a, thereby performing the anterior eye segment scan in this example.

[0120] In the anterior segment scan of this example, the rotation angles of the illumination system 21 and the Scheimpflug imaging system 22 may be arbitrary. For example, as shown in Fig. 14, by rotating the illumination system 21 and the Scheimpflug imaging system 22 by 180 degrees around the axis Rc of the subject's eye E (rotation along the locus R), a data set corresponding to a three-dimensional region around the axis Rc of the subject's eye E is collected.

[0121] 15, the data set collected in the anterior segment scan of this example includes a plurality of data corresponding to a plurality of cross sections P1 to PN arranged radially around the axis Rc of the subject's eye E. The plurality of cross sections P1 to PN correspond to a plurality of rotational positions in the anterior segment scan. The plurality of rotational positions can be defined as a plurality of positions on the trajectory R of the anterior segment scan, and the plurality of cross sections P1 to PN can also be defined in the same way.

[0122] The data corresponding to each cross section Pn is image data for that cross section Pn and includes information corresponding to the wavelength band of the non-monochromatic visible slit light 21b. For example, when the non-monochromatic visible slit light 21b is white light, the data corresponding to each cross section Pn includes RGB information consisting of red (R) information, green (G) information, and blue (B) information. Even when a broadband visible light source or a swept-wavelength visible light source is used, information corresponding to the wavelength band is included. In this embodiment, for example, data including at least two pieces of information (RG information, GB information, RB information, or RGB information) selected from red (R) information, green (G) information, and blue (B) information can be obtained.

[0123] The rotation angle of the illumination system 21 and the Scheimpflug imaging system 22 in the anterior segment scan of this example is not limited to 180 degrees as shown in FIG. 14 . In some embodiments, the illumination system 21 and the Scheimpflug imaging system 22 can be rotated by an angle exceeding 180 degrees. In this case, two or more pieces of data corresponding to one rotation position can be acquired. This allows statistical calculations (such as averaging) for each rotation position and selection of data for each rotation position.

[0124] In some embodiments, conversely, the illumination system 21 and the Scheimpflug imaging system 22 can be rotated by an angle less than 180 degrees. In this case, the anterior segment can be scanned by targeting only a portion of interest in the anterior segment, thereby shortening the examination time.

[0125] The data set collected in step S3 is stored, for example, in a storage device of the control unit 7 or a storage device of the data processing unit 8. The data processing unit 8 applies a predetermined analysis process to the data set (S4).

[0126] This analysis process may be any known process, and may include, for example, corneal curvature analysis, corneal pachymetry, corneal elevation analysis, corneal topography, anterior chamber depth analysis, iridocorneal angle analysis, etc. In distance measurement, pixel spacing is performed to determine the distance corresponding to one pixel (pixel spacing).

[0127] The data processing unit 8 can also correct each piece of data collected in the anterior segment scan. For example, the data processing unit 8 may be configured to correct distortions (trapezoidal distortion, refractive distortion) of each piece of data collected in the anterior segment scan. For details on distortion correction, see, for example, Japanese Patent No. 7154044.

[0128] The control unit 7 displays the color anterior segment image based on the data set collected in step S3 and the analysis data obtained in step S4 on the display unit 11 (S5). The color anterior segment image may have been subjected to correction processing such as distortion correction.

[0129] According to the ophthalmic apparatus 1 of this embodiment, it is possible to generate an anterior segment image similar in appearance to an image obtained by a slit lamp microscope by using a rotational scanning method for anterior segment scanning. Moreover, by using a Scheimpflug optical system, it is possible to obtain an image with a deep depth of field. Therefore, according to the ophthalmic apparatus 1 of this embodiment, it is possible to generate a color anterior segment image with a deep depth of field that faithfully reproduces the appearance of an image obtained by a slit lamp microscope by using a rotational scanning method for anterior segment scanning, which is a special effect that cannot be achieved by conventional ophthalmic apparatuses.

[0130] A description will be given of a modified example of the ophthalmologic apparatus 1 of this embodiment. In the above embodiment, one pair of a Scheimpflug imaging system and an illumination system is provided, but two or more pairs may be provided.

[0131] For example, in one modified example, a pair (first pair) of a first Scheimpflug imaging system and a first illumination system and a pair (second pair) of a second Scheimpflug imaging system and a second illumination system are provided. The first Scheimpflug imaging system is configured to satisfy the Scheimpflug condition and is configured to capture an image of an anterior segment of the subject's eye E to generate first data. The first illumination system is configured to illuminate an object surface of the first Scheimpflug imaging system with a first slit light generated using a first non-monochromatic visible light source. Similarly, the second Scheimpflug imaging system is configured to satisfy the Scheimpflug condition and is configured to capture an image of an anterior segment of the subject's eye E to generate second data. The second illumination system is configured to illuminate an object surface of the second Scheimpflug imaging system with a second slit light generated using a second non-monochromatic visible light source.

[0132] The positional relationship between the first pair and the second pair may be determined arbitrarily. For example, the object plane of the first Scheimpflug imaging system and the object plane of the second Scheimpflug imaging system may be common to each other or may be separate from each other. Furthermore, the wavelength bands of the first non-monochromatic visible light source and the second non-monochromatic visible light source may be equal to each other or may be different from each other. Furthermore, the rotation mechanism 62 may rotate the first pair and the second pair in parallel (e.g., integrally) or separately. The rotation axes of the first pair and the second pair may be common to each other or may be separate from each other.

[0133] Some non-limiting aspects of the ophthalmic apparatus according to the embodiment have been described above. Any two or more aspects according to the present disclosure can be at least partially combined.

[0134] Other Aspects The embodiments of the present disclosure are not limited to ophthalmic devices. Examples of embodiments other than ophthalmic devices include a method for controlling an ophthalmic device, a method for photographing an anterior segment, a program, and a recording medium. According to these embodiments, similar to the embodiments of the ophthalmic device, it is possible to generate a color anterior segment image with a deep depth of field that faithfully reproduces the aspect of an image obtained by a slit lamp microscope by scanning the anterior segment using a rotational scan method.

[0135] Some embodiments provide a method for controlling an ophthalmic apparatus. The ophthalmic apparatus includes a Scheimpflug imaging system, an illumination system, a rotation mechanism, a display, and a processor. The Scheimpflug imaging system is configured to satisfy the Scheimpflug condition and is configured to capture an image of an anterior segment of an eye to be examined and generate data. The illumination system is configured to illuminate an object plane of the Scheimpflug imaging system with slit light generated using a non-monochromatic visible light source. The rotation mechanism is configured to rotate the Scheimpflug imaging system and the illumination system around a predetermined axis. The method according to this embodiment includes a step of causing the processor to control the Scheimpflug imaging system, the illumination system, and the rotation mechanism to cause the Scheimpflug imaging system to generate data sets corresponding to multiple rotation positions (anterior segment scan control step). Furthermore, the method according to this embodiment includes a step of causing the processor to control the display to display images of the anterior segment based on the data sets collected by the anterior segment scan control step (display control step).

[0136] Any of the items described in this disclosure can be combined with the method according to the embodiments.

[0137] Some embodiments provide a program. The program according to the embodiments causes a computer including a processor and a memory to execute the method according to the above-described embodiment. Any of the features described in the present disclosure can be combined with the program according to the embodiments.

[0138] Some embodiments provide a computer-readable non-transitory recording medium. The recording medium according to the embodiments stores a program that causes a computer to execute the method according to the above-described embodiments. Any of the features described in this disclosure can be combined with the recording medium according to the embodiments.

[0139] A computer-readable non-transitory recording medium that can be used as a recording medium in this embodiment may be a recording medium of any form, for example, a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory.

[0140] The embodiments and aspects described in the present disclosure are merely examples, and any modifications (omissions, substitutions, additions, etc.) within the scope of the present invention can be applied to the embodiments and aspects of the present disclosure.

Claims

1. An ophthalmic apparatus comprising: a Scheimpflug imaging system configured to satisfy the Scheimpflug condition and which captures images of the anterior segment of a subject's eye to generate data; an illumination system which illuminates an object surface of the Scheimpflug imaging system with slit light generated using a non-monochromatic visible light source; a rotation mechanism which rotates the Scheimpflug imaging system and the illumination system around a predetermined axis; and a control unit which controls the Scheimpflug imaging system, the illumination system, and the rotation mechanism to cause the Scheimpflug imaging system to generate data sets corresponding to a plurality of rotation positions.

2. The ophthalmic device of claim 1, wherein the non-monochromatic visible light source includes a white light source.

3. The ophthalmologic apparatus according to claim 2, wherein the Scheimpflug imaging system generates the data including RGB information.

4. The ophthalmic device according to any one of claims 1 to 3, wherein the non-monochromatic visible light source includes a wavelength swept light source.

5. The ophthalmic apparatus of claim 4, wherein the swept light source sweeps wavelengths across a visible wavelength band, and the Scheimpflug imaging system generates the data including RGB information.

6. An ophthalmic device according to any one of claims 1 to 5, comprising: a first Scheimpflug imaging system configured to satisfy the Scheimpflug condition and to photograph the anterior segment of the eye to generate first data; a first illumination system configured to illuminate an object surface of the first Scheimpflug imaging system with a first slit light generated using a first non-monochromatic visible light source; a second Scheimpflug imaging system configured to satisfy the Scheimpflug condition and to photograph the anterior segment of the eye to generate second data; and a second illumination system configured to illuminate an object surface of the second Scheimpflug imaging system with a second slit light generated using a second non-monochromatic visible light source.

7. The ophthalmic apparatus according to any one of claims 1 to 6, further comprising a fixation optical system for presenting a fixation target to the subject's eye.

8. The ophthalmic device according to claim 7, wherein the fixation optical system projects fixation light having an intensity higher than that of the slit light onto the subject's eye so as to present a first fixation target positioned within the exit pupil of the illumination system to the subject's eye.

9. The ophthalmic device according to claim 7 or 8, wherein the fixation optical system projects fixation light onto the subject's eye so as to present a second large fixation target positioned within the exit pupil of the illumination system to the subject's eye.

10. An ophthalmic device according to any one of claims 7 to 9, wherein the fixation optical system projects fixation light onto the subject's eye so as to present to the subject's eye a third fixation target, at least a portion of which changes, located within the exit pupil of the illumination system.

11. The ophthalmic apparatus according to any one of claims 7 to 10, wherein the fixation optical system presents a black fourth fixation target arranged within the exit pupil of the illumination system to the subject's eye.

12. An ophthalmic device according to any one of claims 7 to 11, further comprising a housing for the illumination system, wherein the housing is provided with a cutout or a light-transmitting section outside the exit pupil of the illumination system, and the fixation optical system projects fixation light onto the subject's eye through the cutout or the light-transmitting section so as to present a fifth fixation target positioned outside the exit pupil of the illumination system to the subject's eye.

13. An ophthalmic device according to any one of claims 1 to 12, wherein the angle formed between the optical axis of the illumination system and a plane perpendicular to the optical axis of the Scheimpflug photography system is in the range of 0 to 90 degrees, preferably in the range of 30 to 60 degrees, and more preferably in the range of 35 to 53 degrees.

14. An ophthalmic apparatus according to any one of claims 1 to 13, wherein the Scheimpflug photographing system includes an image sensor, and the image sensor is disposed eccentrically with respect to the optical axis of the Scheimpflug photographing system.

15. An ophthalmic device according to claim 14, wherein the image sensor includes a photodetector array and a microlens array configured as an imaging lens group for the photodetector array, and is disposed eccentrically with respect to the optical axis of the Scheimpflug photography system so that the angle formed between the light rays guided to the microlens array by the Scheimpflug photography system and the optical axis of the microlens array is small.

16. An ophthalmic apparatus according to claim 14 or 15, wherein the center position of the light receiving surface of the image sensor is located at a position away from the intersection of the optical axis of the Scheimpflug imaging system and the image plane.

17. An ophthalmic device according to any one of claims 14 to 16, wherein the center position of the light receiving surface of the image sensor is located closer to the optical axis of the illumination system than the intersection of the optical axis of the Scheimpflug imaging system and the image plane.

18. A method for controlling an ophthalmic apparatus for photographing the anterior segment of a subject's eye, the ophthalmic apparatus being configured to satisfy the Scheimpflug condition and including: a Scheimpflug photography system that photographs the anterior segment of the subject's eye to generate data; an illumination system that illuminates an object surface of the Scheimpflug photography system with slit light generated using a non-monochromatic visible light source; a rotation mechanism that rotates the Scheimpflug photography system and the illumination system around a predetermined axis; a display; and a processor, the method including the steps of: causing the processor to control the Scheimpflug photography system, the illumination system, and the rotation mechanism to generate data sets corresponding to a plurality of rotation positions in the Scheimpflug photography system; and causing the processor to control the display to display images of the anterior segment based on the data sets.

19. A computer-readable non-transitory recording medium having recorded thereon a program for causing a computer to execute the method of claim 18.

Images