Ophthalmic observation device

Abstract

An ophthalmological observation device (1) according to an exemplary embodiment comprises an illumination system (30), an imaging system (40), and a focus processing unit (200, 210). The illumination system comprises a light source (32a) that emits illumination light and an indicator member (35) provided with a plurality of indicators (36a, 36b), and projects the illumination light on a subject eye (E) via the indicator member. The imaging system comprises an imaging element (62) and captures an image of the subject eye. The focus processing unit detects a plurality of indicator images from the image captured by the imaging system, and performs focus control on the imaging system on the basis of the plurality of indicator images detected.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Patent Application No. 63 / 106,087, entitled "APPARATUS AND METHOD FOR OPHTHALMIC OBSERVATION," filed October 27, 2020, which is incorporated by reference in its entirety.

[0002] The present disclosure relates to an ophthalmic observation device. [Background technology]

[0003] An ophthalmic observation device is a device for observing a patient's eye (called the subject's eye). Ophthalmic observation is performed in various situations, such as examination, surgery, and treatment, to understand the condition of the subject's eye.

[0004] Conventional ophthalmic observation devices provided the user with a magnified image obtained by an objective lens or a variable magnification optical system through an eyepiece. However, recent ophthalmic observation devices are configured to capture the magnified image obtained by the objective lens or the variable magnification optical system with an imaging element and display the captured image (called digital ophthalmic observation devices). Types of digital ophthalmic observation devices include surgical microscopes, slit lamp microscopes, and fundus cameras. In addition, various types of ophthalmic examination devices, such as refractometers, keratometers, tonometers, specular microscopes, wavefront analyzers, and microperimeters, are also equipped with the functionality of digital ophthalmic observation devices. Cited Document 1 discloses a surgical microscope that functions as a digital ophthalmic observation device.

[0005] In general, an ophthalmic observation device provides an image of an eye to a user (for example, a medical professional such as a doctor). A digital ophthalmic observation device is typically configured to capture moving images using infrared light and / or visible light as illumination light and to display the images obtained in real time. The real-time moving images (videos) provided in this way are called observation images or live images.

[0006] Ophthalmic observation devices are used to observe various parts of a subject's eye. For example, while anterior segment observation can be performed with a standard optical system configuration, posterior segment observation requires optical elements different from those for anterior segment observation, since illumination light must reach the posterior segment through the pupil, and the returning light must be extracted through the pupil and guided to the optical system. Cited documents 2 and 3 disclose surgical microscopes configured to switch between anterior segment observation and posterior segment observation by using or not using a front lens. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2019-162336 [Patent Document 2] Japanese Patent Application Publication No. 2019-013803 [Patent Document 3] Japanese Patent Application Publication No. 2019-092844 Summary of the Invention [Problem to be solved by the invention]

[0008] A typical digital ophthalmic observation device is configured so that when the optical system configuration is changed to switch from anterior to posterior segment observation, the fundus and the image sensor are optically conjugate when the diopter of the subject's eye is emmetropic. However, because the majority of eyes have refractive errors (myopia, hyperopia, etc.) and diopter varies from person to person, the fundus and the image sensor are not conjugate when the optical system configuration for posterior segment observation is applied, and the digital ophthalmic observation device cannot focus on the fundus. Therefore, in conventional digital ophthalmic observation devices, focus adjustment must be performed again after switching to the optical system configuration for posterior segment observation. However, this refocus adjustment is currently omitted by using a separate concave and / or convex lens. Even in this case, fine focus adjustment is required at the end. As is well known in the art, situations requiring similar focus adjustment or fine focus adjustment are not limited to switching from anterior to posterior segment observation.

[0009] One object of the present disclosure is to provide a new method for focus adjustment in a digital ophthalmologic observation device. [Means for solving the problem]

[0010] An ophthalmic observation device according to some exemplary aspects is an ophthalmic observation device including: an illumination system including a light source that emits illumination light and an index member on which a plurality of indexes are provided, and that projects the illumination light onto an eye to be examined via the index member; an imaging system including an image sensor that images the eye to be examined; and a focus processing unit that detects a plurality of index images from an image obtained by the imaging system and performs focus control of the imaging system based on the plurality of index images.

[0011] In the ophthalmologic observation device according to some exemplary aspects, the plurality of indices may include two indices arranged at positions spaced apart from the observation surface by different optical distances.

[0012] In some exemplary embodiments of the ophthalmic observation device, one of the two indices may be arranged on the side of the light source relative to a position optically conjugate with the observation surface, and the other of the two indices may be arranged on the side of the subject's eye relative to the position optically conjugate with the observation surface.

[0013] In the ophthalmologic observation device according to some exemplary aspects, at least one of the plurality of indices may be disposed at a position spaced apart from the optical axis of the illumination system.

[0014] In the ophthalmologic observation device according to some exemplary aspects, the plurality of indices may include at least two indices that are equidistant from the optical axis.

[0015] In the ophthalmologic observation device according to some exemplary aspects, the at least two indices may include two indices that are arranged symmetrically with respect to the optical axis in a direction perpendicular to the optical axis.

[0016] In the ophthalmologic observation device according to some exemplary embodiments, at least two of the plurality of indices may be provided on a single member.

[0017] In the ophthalmologic observation device according to some exemplary aspects, the single member may be a plane-parallel plate that transmits the illumination light.

[0018] In some exemplary aspects of the ophthalmologic observation device, the plurality of indices may include a first indice provided on a first surface of the plane-parallel plate and a second indice provided on a second surface parallel to the first surface.

[0019] In the ophthalmic observation device according to some exemplary aspects, a position optically conjugate with respect to the observation surface may be disposed between the first surface and the second surface.

[0020] In the ophthalmologic observation device according to some exemplary aspects, the position optically conjugate with respect to the observation surface may be disposed at a position equidistant from each of the first surface and the second surface.

[0021] In the ophthalmologic observation device according to some exemplary aspects, the focus processing unit may perform the focus control based on dimensions of the plurality of target images.

[0022] In the ophthalmologic observation device according to some exemplary aspects, the focus processing unit may compare the sizes of the plurality of target images and perform the focus control based on a result of the comparison.

[0023] The ophthalmologic observation device according to some exemplary aspects may further include an objective lens and a first movement mechanism that moves the illumination system and the imaging system in a direction along the optical axis of the objective lens. Furthermore, the focus processing unit may obtain movement control information including at least one of a movement direction and a movement distance based on a result of the comparison, and may control the first movement mechanism based on the movement control information.

[0024] In the ophthalmologic observation device according to some exemplary aspects, the plurality of indices may include a pair of indices of the same size, which are respectively arranged at two positions spaced apart by an equal optical distance in opposite directions along the optical axis of the illumination system from a position optically conjugate with respect to the observation plane. Furthermore, the focus processing unit may perform the focus control so that the sizes of two indices corresponding to the pair of indices are equal.

[0025] In the ophthalmologic observation device according to some exemplary aspects, the focus processing unit may perform the focus control based on blur of the plurality of target images.

[0026] An ophthalmologic observation device according to some exemplary aspects may further include an objective lens, a second movement mechanism that moves the illumination system and the photographing system in a direction perpendicular to the optical axis of the objective lens, an abnormal image detection unit that performs image analysis to detect an abnormal image from the image obtained by the photographing system, and a movement processing unit that controls the second movement mechanism based on the abnormal image when the abnormal image is detected by the abnormal image detection unit.

[0027] The ophthalmologic observation device according to some exemplary aspects may further include a cropping processing unit that crops a region of a predetermined dimension from the image obtained by the imaging system, and an abnormal image detection unit that performs image analysis to detect an abnormal image from the partial image cropped from the image. Furthermore, when the abnormal image detection unit detects the abnormal image, the cropping processing unit may move the region of the predetermined dimension to a region of the image that does not include the detected abnormal image.

[0028] The ophthalmologic observation device according to some exemplary aspects may further include a mode switching unit for switching between a first observation mode for observing a first portion of the subject's eye and a second observation mode for observing a second portion different from the first portion. Furthermore, the focus processing unit may perform detection of the plurality of target images and the focus control in response to switching of the observation mode by the mode switching unit.

[0029] In the ophthalmologic observation device according to some exemplary aspects, the first observation mode may be an anterior ocular segment observation mode for observing an anterior ocular segment of the subject's eye, and the second observation mode may be a posterior ocular segment observation mode for observing a posterior ocular segment of the subject's eye. Furthermore, the mode switching unit may include a lens inserted in an optical path to switch from the anterior ocular segment observation mode to the posterior ocular segment observation mode. [Effects of the Invention]

[0030] According to an exemplary embodiment, it is possible to provide a new method for focus adjustment in a digital ophthalmic observation device. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a schematic diagram showing an example of the configuration of an ophthalmologic observation apparatus (surgical microscope system) according to an exemplary embodiment. [Figure 2] FIG. 1 is a schematic diagram showing an example of the configuration of an ophthalmologic observation apparatus according to an exemplary embodiment. [Figure 3] FIG. 1 is a schematic diagram showing an example of the configuration of an ophthalmologic observation apparatus according to an exemplary embodiment. [Figure 4] FIG. 1 is a schematic diagram showing an example of the configuration of an ophthalmologic observation apparatus according to an exemplary embodiment. [Figure 5] FIG. 10 is a schematic diagram for explaining an example of the operation of the ophthalmologic observation device according to the exemplary embodiment. [Figure 6A] FIG. 10 is a schematic diagram for explaining an example of the operation of the ophthalmologic observation device according to the exemplary embodiment. [Figure 6B] FIG. 10 is a schematic diagram for explaining an example of the operation of the ophthalmologic observation device according to the exemplary embodiment. [Figure 6C] FIG. 10 is a schematic diagram for explaining an example of the operation of the ophthalmologic observation device according to the exemplary embodiment. [Figure 7] FIG. 1 is a schematic diagram showing an example of the configuration of an ophthalmologic observation apparatus according to an exemplary embodiment. [Figure 8] FIG. 10 is a schematic diagram for explaining an example of the operation of the ophthalmologic observation device according to the exemplary embodiment. [Figure 9] FIG. 1 is a schematic diagram showing an example of the configuration of an ophthalmologic observation apparatus according to an exemplary embodiment. [Figure 10A] FIG. 10 is a schematic diagram for explaining an example of the operation of the ophthalmologic observation device according to the exemplary embodiment. [Figure 10B] FIG. 10 is a schematic diagram for explaining an example of the operation of the ophthalmologic observation device according to the exemplary embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0032] Some exemplary aspects of the ophthalmologic observation device according to the embodiment will be described in detail with reference to the drawings. It should be noted that it is possible to combine the matters described in the documents cited in this specification and any known technology with the exemplary aspects.

[0033] An ophthalmic observation device according to an exemplary embodiment is used to grasp the condition of a subject's eye during medical procedures such as surgery, examination, and treatment. The ophthalmic observation device according to the exemplary embodiment described below is a surgical microscope system, but the ophthalmic observation device is not limited to a surgical microscope system. For example, the ophthalmic observation device may be any of a slit lamp microscope, a fundus camera, a refractometer, a keratometer, a tonometer, a specular microscope, a wavefront analyzer, and a microperimeter, or may be a system including any one or more of these. More generally, the ophthalmic observation device may be any ophthalmic device having an observation function.

[0034] The target site for observation using an ophthalmic observation device may be any site of the subject's eye, and may be any site in the anterior segment and / or any site in the posterior segment. Examples of target sites for observation in the anterior segment include the cornea, iris, anterior chamber, angle, lens, ciliary body, and Zinn's zonule. Examples of target sites for observation in the posterior segment include the retina, choroid, sclera, and vitreous body. The target sites for observation are not limited to ocular tissues, but may be any site that is the target of observation in ophthalmology (and / or other departments), such as the eyelid, meibomian gland, and orbit.

[0035] At least a portion of the functionality of the elements disclosed herein is implemented using circuitry or processing circuitry, such as 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 a portion of the disclosed functionality. The term "circuitry," "unit," "means," or the like refers to hardware that performs at least a portion of the disclosed functions or that is programmed to perform at least a portion of the disclosed functions. The hardware may be the hardware disclosed herein or may be 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 a type of circuitry, the term "circuitry," "unit," "means," or the like refers to a combination of hardware and software, where the software is used to configure the hardware and / or the processor.

[0036] <Ophthalmic observation device> The configuration of an exemplary embodiment of an ophthalmic observation device is shown in FIG.

[0037] An ophthalmic observation device 1 (surgical microscope system) according to the embodiment includes an operating device 2, a display device 3, and a surgical microscope 10. In some aspects, the surgical microscope 10 may include at least one of the operating device 2 and the display device 3. In addition, in some aspects, the display device 3 may not be included in the ophthalmic observation device 1. In other words, the display device 3 may be a peripheral device of the ophthalmic observation device 1.

[0038] <Control device 2> The operation device 2 includes an operation device and / or an input device. For example, the operation device 2 may include a button, a switch, a mouse, a keyboard, a trackball, an operation panel, a dial, etc. Typically, the operation device 2 includes a foot switch, similar to a general ophthalmic surgical microscope. The operation device 2 may also be configured to perform operations using voice recognition, eye-gaze input, etc.

[0039] <Display device 3> The display device 3 displays an image of the subject's eye acquired by the surgical microscope 10. The display device 3 includes a display device such as a flat panel display. The display device 3 may also include various display devices such as a touch panel. A typical display device 3 includes a large-screen display device. The display device 3 includes one or more display devices. When the display device 3 includes two or more display devices, for example, one may be a relatively large-screen display device and the other may be a relatively small-screen display device. Furthermore, a configuration may be adopted in which multiple display areas are provided on one display device to display multiple pieces of information.

[0040] The operation device 2 and the display device 3 do not need to be separate devices. For example, a device that integrates an operation function and a display function, such as a touch panel, may be used as the display device 3. In this case, the operation device 2 includes this touch panel and a computer program. The operation content of the operation device 2 is input to a processor (not shown) as an electrical signal. Furthermore, operations and information input may be performed using a graphical user interface (GUI) displayed on the display device 3 and the operation device 2. In some embodiments, the functions of the operation device 2 and the display device 3 may be realized by a touch screen.

[0041] <Surgical microscope 10> The surgical microscope 10 is used to observe the eye (examined eye) of a patient in a supine position. The surgical microscope 10 captures images of the examined eye to generate digital image data (video data). In particular, the surgical microscope 10 generates moving images (video) of the examined eye. The moving images generated by the surgical microscope 10 are transmitted to the display device 3 via a wired and / or wireless signal path and displayed. A user (surgeon) can perform surgery while observing the examined eye using the displayed video (observation image, live image). Some aspects of the surgical microscope 10 may also allow observation through a conventional eyepiece in addition to such video observation.

[0042] In some embodiments, the surgical microscope 10 includes a communication device for transmitting and receiving electrical signals to and from the operation device 2. The operation device 2 receives an operation by a user and generates an electrical signal (operation signal) corresponding to the operation. The operation signal is transmitted to the surgical microscope 10 via a wired and / or wireless signal path. The surgical microscope 10 executes processing corresponding to the received operation signal.

[0043] The observation modes using the surgical microscope 10 of this embodiment include an anterior eye observation mode and a posterior eye observation mode. The anterior eye observation mode is used to observe enlarged images of various parts of the anterior eye (such as the cornea Ec). The posterior eye observation mode is used to observe enlarged images of various parts of the posterior eye (such as the fundus Ef). In the posterior eye observation mode, a front lens 21, which will be described later, is used. When the front lens 21 is arranged in the optical path, the objective lens 20 and the front lens 21 can be considered together as the objective lens.

[0044] Below, we will explain an example of the configuration of the optical system of the surgical microscope 10. For convenience of explanation, the optical axis direction of the objective lens will be referred to as the Z direction (e.g., the vertical direction, up-down direction during surgery), a predetermined direction perpendicular to the Z direction will be referred to as the X direction (e.g., the horizontal direction during surgery, the left-right direction for the surgeon and patient), and a direction perpendicular to both the Z direction and the X direction will be referred to as the Y direction (e.g., the horizontal direction during surgery, the front-back direction for the surgeon, the body axis direction for the patient).

[0045] The observation optical system of the surgical microscope 10 has a pair of optical systems. One optical system acquires image data to be presented to the user's left eye, and the other optical system acquires image data to be presented to the user's right eye. This allows the user to observe with both eyes (binocular observation), and in particular, enables stereoscopic viewing.

[0046] An example of the configuration of the optical system of the surgical microscope 10 is shown in Figures 2 and 3. Figure 2 is a schematic diagram of the optical system as seen from the side of the subject's eye E, and Figure 3 is a schematic diagram of the optical system as seen from the side. For simplicity, the illumination optical system 30 disposed above the objective lens 20 is not shown in Figure 2.

[0047] The surgical microscope 10 includes an objective lens 20, a reflecting mirror RM, a dichroic mirror DM, an illumination optical system 30, and an observation optical system 40. The surgical microscope 10 further includes a front lens 21 used in a posterior segment observation mode. The observation optical system 40 includes a zoom expander 50 and an imaging camera 60. In some embodiments, the illumination optical system 30 (first illumination optical systems 31L and 31R) and / or the observation optical system 40 includes a reflecting mirror RM. In addition, in some embodiments, the illumination optical system 30 (first illumination optical systems 31L and 31R) and / or the observation optical system 40 includes a dichroic mirror DM.

[0048] The objective lens 20 is disposed so as to face the eye E. The optical axis OA of the objective lens 20 is disposed parallel to the Z direction. The objective lens 20 may include two or more lenses.

[0049] The dichroic mirror DM couples the optical path of the illumination optical system 30 (first illumination optical systems 31L and 31R) with the optical path of the observation optical system 40. The dichroic mirror DM is disposed between the zoom expander 50 and the reflecting mirror RM. The dichroic mirror DM reflects illumination light from the illumination optical system 30 (first illumination optical systems 31L and 31R) and guides it to the subject's eye E via the reflecting mirror RM and the objective lens 20 (and the head lens 21), and also transmits return light from the subject's eye E that has been guided by the (head lens 21 and) the objective lens 20 and the reflecting mirror RM, and guides it to the imaging camera 60 via the zoom expander 50.

[0050] The dichroic mirror DM coaxially couples the optical path of the illumination optical system 30 (first illumination optical systems 31L and 31R) with the optical path of the observation optical system 40. That is, the optical axis of the illumination optical system 30 and the optical axis of the observation optical system 40 intersect at the dichroic mirror DM. In this embodiment, the illumination optical system 30 includes a left-eye illumination optical system (31L) and a right-eye illumination optical system (31R), and the observation optical system 40 includes a left-eye observation optical system 40L and a right-eye observation optical system 40R. The dichroic mirror DM coaxially couples the optical path of the left-eye illumination optical system (first illumination optical system 31L) with the optical path of the left-eye observation optical system 40L, and coaxially couples the optical path of the right-eye illumination optical system (first illumination optical system 31R) with the optical path of the right-eye observation optical system 40R. That is, the optical axis OL of the left eye illumination optical system (first illumination optical system 31L) and the optical axis OB of the left eye observation optical system 40L intersect at the dichroic mirror DM, and the optical axis OR of the right eye illumination optical system (first illumination optical system 31R) and the optical axis OB of the right eye observation optical system 40R intersect at the dichroic mirror DM.

[0051] The reflecting mirror RM is disposed above the objective lens 20. The upper end of the optical axis OA of the objective lens 20, which extends in the Z direction, is located at the reflecting mirror RM. The reflecting mirror RM also deflects the optical axes OB of the observation optical systems 40L and 40R, which extend in the Y direction, so that they are parallel to the optical axis OA of the objective lens 20 (Z direction). At the reflecting mirror RM, the optical axis OA of the objective lens 20 is located midway between the optical axis OB of the observation optical system 40L and the optical axis OB of the observation optical system 40R. The first illumination optical systems 31L and 31R are disposed above the dichroic mirror DM. The second illumination optical system 32 is disposed above the objective lens 20. The second illumination optical system 32 is disposed at a position offset toward the dichroic mirror DM with respect to the reflecting mirror RM. In other words, the optical axis OS of the second illumination optical system 32 is located closer to the dichroic mirror DM than the optical axis OA of the objective lens 20.

[0052] The illumination optical system 30 is an optical system for illuminating the subject's eye E via the objective lens 20 (and the front lens 21). The illumination optical system 30 may be configured to illuminate the subject's eye E with one of two or more illumination lights having different color temperatures. The illumination optical system 30 projects illumination light of a specified color temperature onto the subject's eye E under the control of a control unit (200) described below.

[0053] As described above, the illumination optical system 30 includes the first illumination optical systems 31L and 31R and the second illumination optical system 32.

[0054] The illumination method using the first illumination optical systems 31L and 31R is so-called "coaxial illumination," which allows a transillumination image to be obtained using diffuse reflection at the fundus. In this embodiment, the user can observe the transillumination image of the subject's eye E with both eyes. That is, in this embodiment, a transillumination image of the subject's eye E can be captured with both the left-eye observation optical system 40L and the right-eye observation optical system 40R, and the resulting pair of transillumination images can be displayed.

[0055] The optical axis OS of the second illumination optical system 32 is positioned at a position offset in the Y direction from the optical axis OA of the objective lens 20. The first illumination optical systems 31L and 31R and the second illumination optical system 32 are positioned so that the offset of the optical axis OS from the optical axis OA of the objective lens 20 is greater than the offset of the optical axes OL and OR from the optical axis OA of the objective lens 20. This makes it possible to achieve so-called "angled illumination (oblique illumination, tilted illumination)," which makes it possible to observe the subject's eye E with binoculars while preventing the inclusion of ghosts caused by corneal reflection, etc. Furthermore, it becomes possible to observe the unevenness of parts and tissues of the subject's eye E in detail.

[0056] The first illumination optical system 31L includes a light source 31a and a condenser lens 31b. The light source 31a outputs illumination light with a wavelength in the visible region corresponding to a color temperature of, for example, 3000K (Kelvin). The illumination light output from the light source 31a passes through the condenser lens 31b, is reflected by the dichroic mirror DM, is reflected by the reflecting mirror RM, passes through the objective lens 20 (and the head lens 21), and is incident on the subject's eye E. The same is true for the first illumination optical system 31R.

[0057] The second illumination optical system 32 includes a light source 32a, a lens 32b, and an index member 35. The index member 35 is disposed between the light source 32a and the lens 32b. The light source 32a may include a condenser lens (not shown). The light source 32a outputs illumination light with a wavelength in the visible region corresponding to a color temperature of, for example, 4000K to 6000K. As will be described in detail later, the index member 35 is provided with a plurality of indexes. The lens 32b functions to project the plurality of indexes provided on the index member 35 onto the subject's eye E.

[0058] The index member 35 provides a plurality of indexes used for focus adjustment (focus control) of the observation optical system 40 with respect to the subject's eye E. The index member 35 may have any configuration and may include any device or element. For example, the index member 35 may be one or more optical elements (e.g., a light-transmitting plate-like member, typically a plane-parallel plate) provided with a reticle (e.g., a cross index or a pinhole index) as an index, one or more diaphragm members capable of using an aperture as an index, a plurality of light sources (e.g., light-emitting elements such as LEDs), or a transmissive display (e.g., a transmissive LCD or a transmissive OLED).

[0059] The illumination light output from the light source 32a passes through the index member 35 and the lens 32b, and is refracted by the objective lens 20 (and the front lens 21) to enter the eye E without passing through the reflecting mirror RM.

[0060] The arrangement and manner of the multiple indicators provided on the indicator member 35 may be arbitrary. Furthermore, the arrangement and / or manner of the multiple indicators may be changeable. The manner (shape, size, color, etc.) of the multiple indicators may be the same or different from each other. Several examples of the arrangement of the multiple indicators are described below. Note that it is possible to at least partially combine at least two of these examples.

[0061] A first example of the arrangement of multiple indices will be described. In this example, attention is focused on the optical distance from the observation surface. The multiple indices in this example include at least two indices that are at different optical distances from the observation surface. The observation surface is, so to speak, the position at which the user wants to focus most (the position (site, depth) that the user pays attention to when observing the subject's eye E), and is a position (observation position) that is desired to be optically conjugate with the image sensor 62 of the observation optical system 40.

[0062] If the subject's eye E is emmetropic, and this optical conjugate relationship is achieved in the anterior segment observation mode, even if the front lens 21 is inserted into the optical path and the mode is switched to the posterior segment observation mode, the focus will be on the desired observation surface of the posterior segment (typically the fundus Ef (retina)), so there is almost no need for focus adjustment when switching to the observation area.

[0063] On the other hand, if the subject's eye E has a refractive error, even if a suitable optical conjugate relationship is achieved in the anterior segment observation mode, the focus will shift from the desired observation plane of the posterior segment when the mode is switched to the posterior segment observation mode. Therefore, by projecting two targets according to this specific example and taking an image, two target images with different focus states are depicted in the captured image, and the current focus state of the observation optical system 40 can be grasped from parameters related to these target images (dimensions, blur, etc.), making it possible to perform focus adjustment (details will be described later).

[0064] A specific example of the first example will be described. In this specific example, a plane conjugate to the observation plane is arranged between two targets. In other words, one target is arranged on the light source 32a side of a plane optically conjugate to the observation plane (a plane intersecting the optical path of the second illumination optical system 32), and the other target is arranged on the lens 32b side (the side of the subject's eye E) of that plane. By referring to two target images based on these two targets, it is possible to grasp the focus state and perform focus adjustment.

[0065] A second example of the arrangement of multiple indices will be described. At least one of the multiple indices in this example is not arranged on the optical axis OS of the second illumination optical system 32. That is, at least one of the multiple indices in this example is arranged at a position away from the optical axis OS of the second illumination optical system 32. If two (or more) indices are arranged together on the optical axis OS, their images will overlap in the captured image, making them indistinguishable, and the indices will become meaningless. This example aims to avoid such problems, and two (or more) indices are arranged at different positions in directions (X and Y directions) perpendicular to the optical axis OS.

[0066] A specific example of the second example will be described. In this specific example, the multiple indices include at least two indices that are equidistant from the optical axis OS of the second illumination optical system 32. In other words, when the three-dimensional coordinates (XYZ coordinates) of each of the at least two indices are projected onto an XY plane perpendicular to the optical axis OS, at least two projected positions (XY coordinates) corresponding to the at least two indices are arranged on the same circle centered on the XY coordinates of the optical axis OS.

[0067] For example, the at least two indices equidistant from the optical axis OS include two indices arranged symmetrically with respect to the optical axis OS in directions (X and Y directions) perpendicular to the optical axis OS. In other words, when the X, Y and Z coordinates of the two indices are projected onto the XY plane, the two X and Y coordinates corresponding to the two indices are arranged point-symmetrically with respect to the X and Y coordinates of the optical axis OS.

[0068] By arranging multiple indices in this orderly manner, the analysis range for detecting index images (described later) can be narrowed compared to when multiple indices are arranged irregularly, making it possible to simplify and speed up the process. Furthermore, when manually fine-tuning the focus while referring to the displayed image in which the index images are depicted, the user can easily find the index images, and furthermore, it becomes easy to compare multiple index images.

[0069] A third example of the arrangement of multiple indicators will be described. In this example, at least two of the multiple indicators are provided on a single member. This single member is included in indicator member 35. In general, indicator member 35 is made up of one or more members. According to this example, it is possible to simplify the configuration of indicator member 35 compared to, for example, a case where two indicators are provided on separate members. Note that indicator member 35 may also be made up of two or more members with multiple indicators dispersedly arranged.

[0070] A specific example of the third example will be described. The single member in this example is a plane-parallel plate that transmits illumination light output from the light source 32a. The multiple indices may include a first indice provided on a first surface of the plane-parallel plate and a second indice provided on a second surface parallel to the first surface. In other words, a configuration in which indices are provided on each of two parallel surfaces (referred to as "both surfaces") of the plane-parallel plate may be used. Furthermore, a position conjugate to the observation plane may be located between both surfaces of the plane-parallel plate. In other words, a position conjugate to the observation plane may be located inside the plane-parallel plate. Additionally, a position conjugate to the observation plane may be located on the center plane of the plane-parallel plate. In other words, a position optically conjugate to the observation plane may be located at a position equidistant from each of the two surfaces of the plane-parallel plate. This specific example provides one configuration example of the first example described above. Generally, when the index member 35 includes a plate-like member such as a plane-parallel plate, the position of the plate-like member relative to the optical axis OS of the second illumination optical system 32 may be arbitrarily determined. For example, the plane-parallel plate may be arranged so that its two optical surfaces intersect orthogonally or obliquely with the optical axis OS.

[0071] The color temperature of the illumination light from the first illumination optical systems 31L and 31R may be lower than the color temperature of the illumination light from the second illumination optical system 32. With this configuration, it becomes possible to observe the subject's eye E in warm colors using the first illumination optical systems 31L and 31R, and to observe the structure and shape of the subject's eye E in detail.

[0072] In some embodiments, each of the optical axes OL and OR is movable relative to the optical axis OA of the objective lens 20. The direction of this relative movement is a direction intersecting the optical axis OA of the objective lens 20, and this relative movement is expressed by a displacement vector in which at least one of the X and Y components is non-zero. In some embodiments, each of the optical axes OL and OR may be movable independently. On the other hand, in some embodiments, the optical axes OL and OR may be movable integrally. For example, the surgical microscope 10 includes a movement mechanism (31d) that moves the first illumination optical systems 31L and 31R independently or integrally, and this movement mechanism moves the first illumination optical systems 31L and 31R independently or integrally in a direction intersecting the optical axis OA of the objective lens 20. This makes it possible to adjust the visibility of the subject's eye E. In some embodiments, the movement mechanism operates under the control of a control unit (200) described below.

[0073] In some aspects, the optical axis OS is movable relative to the optical axis OA of the objective lens 20. The direction of this relative movement is a direction intersecting the optical axis OA of the objective lens 20, and this relative movement is expressed by a displacement vector in which at least one of the X and Y components is non-zero. For example, the surgical microscope 10 is provided with a movement mechanism (32d) that moves the second illumination optical system 32, and this movement mechanism moves the second illumination optical system 32 in a direction intersecting the optical axis OA of the objective lens 20. This makes it possible to adjust the visibility of irregularities in the parts and tissues of the subject's eye E. In some aspects, the movement mechanism operates under the control of a control unit (200) described below.

[0074] As described above, in this embodiment, illumination light is projected toward the subject's eye E from a position directly above the objective lens 20, and the optical axis OB of the observation optical system 40 is arranged horizontally (along the Y direction), but the arrangement of the optical system is not limited to this. For example, the observation optical system 40 may be arranged so that the angle between the optical axis OB of the observation optical system 40 and a plane (XY plane) perpendicular to the optical axis OA of the objective lens 20 is ±20 degrees or less.

[0075] According to the configuration of this embodiment, the observation optical system 40, which generally has a longer optical path length than the illumination optical system 30, is arranged substantially parallel to the XY plane, and therefore does not obstruct the field of view of the surgeon, as is the case with conventional surgical microscopes in which the observation optical system is arranged vertically in front of the surgeon's eyes. Therefore, the surgeon can easily view the screen of the display device 3 installed in front of him / her. In other words, the visibility of the displayed information (images and videos of the subject's eye E, and various other reference information) during surgery, etc. is improved. Furthermore, because the housing is not arranged in front of the surgeon's eyes, the surgeon does not feel oppressive, and the burden on the surgeon is reduced.

[0076] The observation optical system 40 is an optical system for observing an image formed based on the return light of the illumination light incident from the subject's eye E via (the front lens 21 and) the objective lens 20. In this embodiment, the observation optical system 40 guides the image to the imaging element of the imaging camera 60. The observation optical system 40 functions as an imaging system.

[0077] As described above, the observation optical system 40 includes the left-eye observation optical system 40L and the right-eye observation optical system 40R. The configuration of the left-eye observation optical system 40L is similar to the configuration of the right-eye observation optical system 40R. In some aspects, the optical arrangements of the left-eye observation optical system 40L and the right-eye observation optical system 40R may be changeable independently of each other.

[0078] The zoom expander 50 is also called a beam expander, a variable beam expander, etc. The zoom expander 50 includes a left-eye zoom expander 50L and a right-eye zoom expander 50R. The configuration of the left-eye zoom expander 50L is similar to the configuration of the right-eye zoom expander 50R. In some aspects, the optical arrangements of the left-eye zoom expander 50L and the right-eye zoom expander 50R may be changeable independently of each other.

[0079] The left-eye zoom expander 50L includes a plurality of zoom lenses 51, 52, and 53. At least one of the plurality of zoom lenses 51, 52, and 53 is movable in the optical axis direction by a magnification change mechanism (a magnification change mechanism 50Ld described below).

[0080] Similarly, the right-eye zoom expander 50R includes a plurality of zoom lenses 51, 52, and 53, and at least one of the plurality of zoom lenses 51, 52, and 53 is movable in the optical axis direction by a magnification change mechanism (a magnification change mechanism 50Rd described below).

[0081] The magnification change mechanism may be configured to move each zoom lens of the left-eye zoom expander 50L and each zoom lens of the right-eye zoom expander 50R independently or integrally in the optical axis direction, thereby changing the magnification when photographing the subject's eye E. In some aspects, the magnification change mechanism operates under the control of a control unit (200) described below.

[0082] The imaging camera 60 is a device that captures an image formed by the observation optical system 40 and generates digital image data, and is typically a digital camera (digital video camera). The imaging camera 60 includes a left-eye imaging camera 60L and a right-eye imaging camera 60R. The configuration of the left-eye imaging camera 60L is similar to the configuration of the right-eye imaging camera 60R. In some aspects, the optical arrangements of the left-eye imaging camera 60L and the right-eye imaging camera 60R can be changed independently of each other.

[0083] The left-eye imaging camera 60L includes an imaging lens 61 and an imaging element 62. The imaging lens 61 forms an image based on the returned light that has passed through the left-eye zoom expander 50L on the imaging surface of the imaging element 62. The imaging element 62 is an area sensor, and may typically be a charge-coupled device (CCD) image sensor or a complementary metal-oxide semiconductor (CMOS) image sensor. The imaging element 62 operates under the control of a control unit (200) described below.

[0084] The right-eye imaging camera 60R includes an imaging lens 61 and an imaging element 62. The imaging lens 61 forms an image based on the returned light that has passed through the right-eye zoom expander 50R on the imaging surface of the imaging element 62. The imaging element 62 is an area sensor, and may typically be a CCD image sensor or a CMOS image sensor. The imaging element 62 operates under the control of a control unit (200) described below.

[0085] <Processing system> Some examples of the processing system of the ophthalmologic observation device 1 will be described with reference to Fig. 4. Any two or more of the various configuration examples described below can be at least partially combined.

[0086] The control unit 200 controls each unit of the ophthalmic observation device 1. The control unit 200 includes a main control unit 201 and a storage unit 202. The main control unit 201 includes a processor and controls each unit of the ophthalmic observation device 1. For example, in order to realize the functions according to this embodiment, the processor can read and execute programs stored in the storage unit 202 or other storage devices, and can also use (reference, process, calculate, etc.) data and information stored in the storage unit 202 or other storage devices.

[0087] The main control unit 201 can control each of the two light sources 31a of the illumination optical system 30, control the light source 32a of the illumination optical system 30, control each of the two image sensors 62 of the observation optical system 40, control each of the movement mechanisms 31d and 32d, control each of the magnification mechanisms 50Ld and 50Rd, control the operation device 2, control the display device 3, etc.

[0088] Control of the light source 31a includes turning the light source on and off, adjusting the light intensity, adjusting the illumination aperture, etc. Control of the light source 32a includes turning the light source on and off, adjusting the light intensity, adjusting the illumination aperture, etc. If the illumination optical system 30 includes a light source whose color temperature can be changed, the main control unit 201 can change the color temperature of the output illumination light by controlling this light source.

[0089] Control of the image sensor 62 includes exposure adjustment, gain adjustment, shooting rate adjustment, etc. The main control unit 201 can control the two image sensors 62 so that the shooting timings of the two image sensors 62 coincide, or control the two image sensors 62 so that the difference in shooting timing between the two image sensors 62 is within a predetermined time. Furthermore, the main control unit 201 can control the reading of digital data obtained by each image sensor 62.

[0090] The movement mechanism 31d moves the two light sources 31a independently or integrally in a direction intersecting the optical axis of the objective lens 20. The main controller 201 controls the movement mechanism 31d to move the optical axes OL and OR of the illumination optical system 30 independently or integrally with respect to the optical axis OA of the objective lens 20.

[0091] The moving mechanism 32d moves the light source 32a in a direction intersecting the optical axis of the objective lens 20. The main controller 201 can move the optical axis OS relative to the optical axis OA of the objective lens 20 by controlling the moving mechanism 32d.

[0092] The movement mechanism 70 moves the surgical microscope 10. For example, the movement mechanism 70 is configured to integrally move at least a portion of the illumination optical system 30 and the observation optical system 40. This makes it possible to change the relative positions of at least a portion of the illumination optical system 30 and the observation optical system 40 with respect to the subject's eye E while maintaining the relative positional relationship between at least a portion of the illumination optical system 30 and the observation optical system 40. In some aspects, the movement mechanism 70 is configured to integrally move the first illumination optical systems 31L and 31R and the observation optical system 40. This makes it possible to change the relative positions of the first illumination optical systems 31L and 31R and the observation optical system 40 with respect to the subject's eye E while maintaining the coaxial illumination state. In some aspects, the movement mechanism 70 is configured to integrally move the second illumination optical system 32 and the observation optical system 40. This makes it possible to change the relative positions of the second illumination optical system 32 and the observation optical system 40 with respect to the subject's eye E while maintaining the illumination angle of oblique illumination. In some aspects, the movement mechanism 70 is configured to integrally move the first illumination optical systems 31L and 31R, the second illumination optical system 32, and the observation optical system 40. This makes it possible to change the relative positions of the illumination optical system 30 and the observation optical system 40 with respect to the subject's eye E while maintaining both the coaxial illumination state and the illumination angle of oblique illumination.

[0093] The movement mechanism 70 can move the surgical microscope 10 in any direction. For example, the movement mechanism 70 may be capable of moving the surgical microscope 10 three-dimensionally. That is, the movement mechanism 70 may be capable of moving the surgical microscope 10 in each of the X direction, Y direction, and Z direction, or may be capable of moving the surgical microscope 10 in any direction that is a combination of at least two of the X direction, Y direction, and Z direction.

[0094] Movement in the X and Y directions (movement in the X direction, movement in the Y direction, and movement in a combined direction of the X and Y directions) is performed by various integrated movements of the illumination optical system 30 and the observation optical system 40. The group of elements of the movement mechanism 70 for moving the surgical microscope 10 in the X and Y directions corresponds to the second movement mechanism.

[0095] Movement in the Z direction is performed to adjust the focus of the observation optical system 40. By moving the observation optical system 40 in the Z direction, the focal point of the observation optical system 40 moves in the Z direction. The group of elements of the movement mechanism 70 for moving the surgical microscope 10 in the Z direction corresponds to the first movement mechanism. Note that the method for adjusting the focus of the observation optical system 40 is not limited to this. For example, a focus lens and a mechanism for moving the lens may be provided in the observation optical system (photography system), as in a fundus camera.

[0096] In addition, when the front lens 21 is arranged in the optical path, focus adjustment may be performed by moving the front lens 21, and when the front lens 21 is not arranged in the optical path, focus adjustment may be performed by moving the objective lens 20.

[0097] More generally, the ophthalmic observation device 1 may be configured to perform focus adjustment by moving at least a part of the illumination optical system 30, moving at least a part of the observation optical system 40, moving the objective lens 20, and moving the front lens 21, or by a combination of two or more of these.

[0098] The movement mechanism 70 operates under the control of the control unit 200 .

[0099] In some aspects, the main control unit 201 can control at least two of the moving mechanisms 31d, 32d, and 70 in a coordinated manner.

[0100] The magnification change mechanism 50Ld moves at least one of the multiple zoom lenses 51 to 53 of the left-eye zoom expander 50L in the optical axis direction. The main controller 201 can change the magnification of the left-eye observation optical system 40L by controlling the magnification change mechanism 50Ld.

[0101] Similarly, the magnification change mechanism 50Rd moves at least one of the multiple zoom lenses 51 to 53 of the right-eye zoom expander 50R in the optical axis direction. The main controller 201 can change the magnification of the right-eye observation optical system 40R by controlling the magnification change mechanism 50Rd.

[0102] The control over the operation device 2 includes operation permission control, operation prohibition control, and transmission control and / or reception control of an operation signal from the operation device 2. The main control unit 201 receives an operation signal generated by the operation device 2 and executes control corresponding to the received signal.

[0103] Control of the display device 3 includes information display control, etc. The main control unit 201, as a display control unit, can cause the display device 3 to display an image based on the digital image data generated by the imaging element 62. Typically, the main control unit 201 can cause the display device 3 to display a pair of images (a pair of moving images) in parallel based on a pair of video data (video signals) generated in parallel by the imaging element 62. The main control unit 201 can also cause the display device 3 to display a still image (frame) included in one of the pair of images. Furthermore, the main control unit 201 can cause the display device 3 to display an image (moving image, still image, etc.) obtained by processing the digital image data generated by the imaging element 62. The main control unit 201 can also cause the display device 3 to display any information generated by the ophthalmic observation device 1 or any information acquired by the ophthalmic observation device 1 from outside.

[0104] The main control unit 201 can display a left-eye image by sequentially displaying on the display device 3 digital image data (frames) sequentially generated as left-eye image data by the imaging element 62 of the left-eye observation optical system 40L, and can display a right-eye image by sequentially displaying on the display device 3 digital image data (frames) sequentially generated as right-eye image data by the imaging element 62 of the right-eye observation optical system 40R. Here, the left and right imaging elements 62 may be synchronized with each other, and the display of the left-eye image and the display of the right-eye image may be synchronized with each other. This allows the ophthalmologic observation device 1 to display on the display device 3 left and right frames obtained substantially simultaneously by the left and right imaging elements 62 substantially simultaneously, and synchronize display updates.

[0105] The video data acquired by the observation optical system 40 may be processed by the data processing unit 210 and then displayed on the display device 3 by the main control unit 201. The data processing unit 210 can sequentially apply predetermined processing (image processing) to digital image data (frames) sequentially generated as left-eye video data by the image sensor 62 of the left-eye observation optical system 40L, while sequentially applying predetermined processing (image processing) to digital image data (frames) sequentially generated as right-eye video data by the image sensor 62 of the right-eye observation optical system 40R. Here, the left and right image sensors 62 may be synchronized with each other, and the processing of the left-eye video data and the processing of the right-eye video data may be synchronized with each other. That is, the data processing unit 210 can process, in parallel, left and right frames acquired substantially simultaneously by the left and right image sensors 62. The left and right frames processed in parallel are sent to the main control unit 201, for example, as a pair of frames (i.e., associated with each other). The main control unit 201 receives a pair of frames (a left-eye frame and a right-eye frame) sequentially input from the data processing unit 210, and sequentially displays the sequentially input left-eye frames on the display device 3 to display a left-eye image, while sequentially displaying the sequentially input right-eye frames on the display device 3 to display a right-eye image. Here, the display of the left-eye image and the right-eye image may be synchronized with each other. This allows the ophthalmologic observation device 1 to process frames obtained substantially simultaneously by the left and right imaging elements 62 in parallel and display them substantially simultaneously on the display device 3, thereby synchronizing display updates.

[0106] The main controller 201 can display the left-eye image and the right-eye image on the display device 3 in a manner that allows stereoscopic viewing. For example, the main controller 201 can create a pair of left and right parallax images from left-eye and right-eye frames acquired substantially simultaneously, and display this pair of parallax images on the display device 3. A user (such as a surgeon) can recognize the pair of parallax images as a stereoscopic image using a known stereoscopic viewing method. Any stereoscopic viewing method can be applied to this embodiment, and can be, for example, a stereoscopic viewing method with the naked eye, a stereoscopic viewing method using an auxiliary device (such as polarized glasses), a stereoscopic viewing method using image processing (such as image synthesis or rendering) on left-eye and right-eye frames, a stereoscopic viewing method that simultaneously displays a pair of parallax images, a stereoscopic viewing method that switches between displaying a pair of parallax images, or a stereoscopic viewing method that combines two or more of these methods.

[0107] The data processing unit 210 executes various types of data processing. Some examples of processing that the data processing unit 210 can execute are described below. The data processing unit 210 (each of its elements) includes a processor that operates according to predetermined software (programs), and is realized by cooperation between hardware and software. The data processing unit 210 acts as a focus processing unit together with the control unit 200 (main control unit 201).

[0108] The ophthalmologic observation device 1 of this embodiment captures an image while projecting a plurality of indices onto the subject's eye E with illumination light, detects a plurality of indices from the obtained image (video data, frame), and performs focus control of the observation optical system 40. The data processing unit 210 executes a process of detecting a plurality of indices corresponding to a plurality of indices from the image of the subject's eye E. The focus control based on the detected plurality of indices images is performed by the main control unit 201 controlling the moving mechanism 70.

[0109] The data processing unit 210 is configured to detect index images from the image using any region extraction method. At this time, the data processing unit 210 can perform index image detection according to a processing procedure created in consideration of the form and / or arrangement of each index provided on the index member 35.

[0110] Several examples of index image detection taking into consideration the aspect of the index will be described. Considering that if the index is a reticle, the index image is rendered relatively dark, and if the index is a light source, the index image is rendered relatively bright, the data processing unit 210 can perform index image detection using brightness threshold processing such as binarization. Furthermore, if the color of the index is distinctive, the data processing unit 210 can perform index image detection using color analysis processing such as characteristic color extraction. Furthermore, if the shape of the index is distinctive, the data processing unit 210 can perform index image detection using shape analysis processing such as pattern matching. The data processing unit 210 may also be configured to perform index image detection using any segmentation method. Generally, segmentation is processing for identifying a partial region in an image. Segmentation may include any known image processing technique, such as segmentation using image processing such as edge detection and / or segmentation using machine learning (e.g., deep learning).

[0111] When the arrangement of the index is taken into consideration, for example, the data processing unit 210 can determine the search range in the image frame based on the arrangement of the index on the index member 35. Note that the search range may be determined in advance based on the arrangement of the optical system. When the arrangement of the optical system is variable, the data processing unit 210 can determine the search range in the current optical system arrangement based on the search range determined in advance for the default optical system arrangement and the current optical system arrangement.

[0112] <Autofocus> Several examples of the operation (autofocus) of the ophthalmologic observation device 1 of this embodiment will be described. Note that, although the operation when shifting from an anterior eye segment observation mode to a posterior eye segment observation mode will be described below as an example, similar operations can be performed in other situations. For example, it will be understood by those skilled in the art that similar operations can be performed when shifting from a posterior eye segment observation mode to an anterior eye segment observation mode or in any other case.

[0113] A first example of the operation of the ophthalmologic observation device 1 will be described. Consider the case of transitioning from an anterior eye observation mode to a posterior eye observation mode in a state where the observation surface is placed on the cornea Ec (a state where the cornea Ec and the image sensor 62 are in an optically conjugate relationship). As described above, transition from the anterior eye observation mode to the posterior eye observation mode is achieved by inserting the front lens 21 between the objective lens 20 and the subject's eye E.

[0114] In some aspects, the ophthalmic observation device 1 can automatically detect that the head lens 21 has been inserted into the optical path. For example, when a user performs an operation to insert the head lens 21 into the optical path, the ophthalmic observation device 1 can detect the movement of a member (such as an arm) supporting the head lens 21 using an encoder or microswitch (not shown) and start processing related to focus control. As another example, when the head lens 21 is inserted into the optical path under the control of the main control unit 201, the ophthalmic observation device 1 can start processing related to focus control after performing the control, for example. As yet another example, the ophthalmic observation device 1 can detect that the mode has shifted from the anterior eye segment observation mode to the posterior eye segment observation mode based on a change in the image caused by the insertion of the head lens 21 into the optical path.

[0115] The process related to focus control in this example starts with providing multiple indices by the index member 35. In some aspects, the index member 35 is inserted into the optical path of the second illumination optical system 32 under the control of the main controller 201, or multiple indices are displayed on a transmissive display serving as the index member 35 under the control of the main controller 201.

[0116] Next, the main controller 201 turns on the light source 32a of the second illumination optical system 32. As a result, illumination light output from the light source 32a is projected onto the subject's eye E via the index member 35. The observation optical system 40 acquires an image (video) in which a plurality of index images corresponding to the plurality of indexes projected onto the subject's eye E are depicted. The main controller 201 sequentially transfers frames (still images) sequentially acquired by the observation optical system 40 to the data processor 210.

[0117] The data processing unit 210 sequentially detects multiple target images from sequentially input frames. The multiple targets include two targets positioned at different optical distances from the observation surface (e.g., the retina). In this case, the two target images corresponding to the two targets have different blur states. For example, if one of the two targets is positioned on the light source 32a side relative to a position optically conjugate with the observation surface, and the other is positioned on the subject's eye E side relative to a position optically conjugate with the observation surface, when the focal point of the observation optical system 40 is located in front of the observation surface (the objective lens 20 side), the degree of focus on the one target becomes higher (i.e., the blur of the other target becomes larger), and when the focal point of the observation optical system 40 is located behind the observation surface, the degree of focus on the other target becomes higher (i.e., the blur of the one target becomes larger). Note that when the focal point (almost) coincides with the observation surface, the degree of blur of the two target images becomes equal. For example, if two indices have the same size, when the focus is (almost) aligned with the observation surface, the size of the two indices will be equivalent. In this way, the indices that are focused will be reversed depending on the position of the focus relative to the observation surface. By utilizing this, it is possible to determine whether the focus is on the near side or the far side relative to the observation surface. Note that any known blur quantification method can be applied to evaluate the magnitude of blur.

[0118] In this way, the data processing unit 210 of this example can determine the position of the focal point relative to the observation surface based on the blur of the multiple target images, and can determine the direction of movement of the surgical microscope 10 to align the focal point with the observation surface. Furthermore, the data processing unit 210 can determine the amount of movement (movement distance) of the surgical microscope 10 to align the focal point with the observation surface from (comparison of) the degree of blur of the multiple target images.

[0119] At least one of the movement direction and movement amount calculated by the data processing unit 210 is provided as movement control information to the main control unit 201. The main control unit 201 controls the movement mechanism 70 based on the movement control information, thereby performing focus adjustment (focus control) to adjust the focus of the observation optical system 40 to the observation surface (e.g., the retina).

[0120] According to this first example, it is possible to reduce the workload of the user, shorten the surgery time, and reduce the burden on the user and the patient.

[0121] A second example of the operation of the ophthalmologic observation device 1 will be described. As in the first example, a case where the mode is shifted from the anterior eye segment observation mode to the posterior eye segment observation mode will be considered. See FIG. 5. FIG. 5 shows an outline of the second illumination optical system 32.

[0122] The lens 32c is a condenser lens provided in the light source 32a (as described above). The lens 32c acts as a collimator lens that converts the illumination light output from the light source device 32a into a parallel beam.

[0123] The index member 35 in this example is a plane-parallel plate. A first index 36a is formed on a surface 35a of the plane-parallel plate 35 facing the light source 32a, and a second index 36b is formed on a surface 35b (the surface facing the eye E) parallel to the surface 35a. The first index 36a and the second index 36b may have any shape. For example, the shape of the first index 36a and the shape of the second index 36b may be the same (e.g., circular), and the dimensions of the first index 36a and the second index 36b may be the same. Note that in FIG. 5, the first index 36a and the second index 36b are represented by different shapes to enhance their distinguishability.

[0124] The first index 36a is arranged at a position spaced a first distance apart in a first direction (upward in FIG. 5 ) perpendicular to the optical axis OS of the second illumination optical system 32. The second index 36b is arranged at a position spaced a second distance apart in a second direction (downward in FIG. 5 ) perpendicular to the optical axis OS and different from the first direction. The first and second distances may or may not be equal. The first and second directions may or may not be opposite directions relative to the optical axis OS. In this example, the first and second distances are equal and the first and second directions are opposite directions relative to the optical axis OS. That is, in this example, the first index 36a and the second index 36b are arranged symmetrically (point-symmetrically) with respect to the optical axis OS in the direction (XY direction) perpendicular to the optical axis OS.

[0125] Reference numeral 35c denotes a surface located equidistant from the first surface 35a and the second surface 35b. That is, surface 35c is the central plane of the plane-parallel plate 35, parallel to both the first surface 35a and the second surface 35b and located equidistant from both surfaces. Surface 35c is optically conjugate with the observation plane 81. The first target image 82a formed by the second illumination optical system 32 is an image of the first target 36a and is formed at a position optically conjugate with the first target 36a. Similarly, the second target image 82b formed by the second illumination optical system 32 is an image of the second target 36b and is formed at a position optically conjugate with the second target 36b.

[0126] Reference numeral 80 simply denotes an optical element group arranged between the plane-parallel plate 35 and an observation surface 81 (e.g., the retina). When the optical systems shown in Figures 2 and 3 are applied, the optical element group 80 includes the lens 32b and the objective lens 20 in the anterior eye segment observation mode, and includes the lens 32b, the objective lens 20, and the front lens 21 in the posterior eye segment observation mode.

[0127] The illumination light output from the light source 32a is converted into parallel light by the lens 32c, passes through the plane-parallel plate 35 on which the first target 36a and the second target 36b are provided, and is projected onto the subject's eye E via the optical element group 80. When the subject's eye E is photographed with the observation optical system 40 while the illumination light is projected, an image (video) depicting the first target image 82a and the second target image 82b is obtained. In this example, the positional relationship between the focal point of the observation optical system 40 and the observation plane 81 is determined using these two target images 82a and 82b.

[0128] Some examples of the first target image 82a and the second target image 82b depicted in the images (frames) obtained in this example are shown in FIGS. 6A, 6B, and 6C.

[0129] 6A is a simplified illustration of an image obtained when the focal point of the observation optical system 40 is located closer to the object (the objective lens 20) than the observation plane 81. In this case, the focal point of the observation optical system 40 is optically closer to the position where the first target image 82a is formed (the position optically conjugate with the first target 36a) than to the position where the second target image 82b is formed (the position optically conjugate with the second target 36b). Therefore, the first target image 82a in the image 91 has a relatively good focus state (small blur), while the second target image 82b in the image 91 has a relatively poor focus state (large blur). In other words, when the first target image 82a and the second target image 82b detected by the data processing unit 210 are compared, the size of the first target image 82a is smaller than the size of the second target image 82b.

[0130] 6B is a simplified illustration of an image obtained when the focal point of the observation optical system 40 is located behind the observation surface 81 (on the opposite side from the objective lens 20). In this case, the focal point of the observation optical system 40 is optically closer to the position where the second target image 82b is formed than to the position where the first target image 82a is formed. Therefore, the first target image 82a in the image 92 is relatively poorly focused (largely blurred), while the second target image 82b in the image 91 is relatively well focused (smallly blurred). In other words, when the first target image 82a and the second target image 82b detected by the data processing unit 210 are compared, the size of the first target image 82a is larger than the size of the second target image 82b.

[0131] 6C is a simplified representation of an image obtained when the focal point of the observation optical system 40 is (almost) coincident with the observation plane 81. In this case, the distance from the focal point of the observation optical system 40 to the position where the first target image 82a is formed is optically (almost) equal to the distance from the focal point of the observation optical system 40 to the position where the second target image 82b is formed. Therefore, the focus state of the first target image 82a and the focus state of the second target image 82b in the image 93 are equivalent. In other words, when the first target image 82a and the second target image 82b detected by the data processing unit 210 are compared, the dimensions of the first target image 82a and the second target image 82b are approximately equal.

[0132] As can be seen from the above explanation, according to this example, it is possible to grasp the focus state of the observation optical system 40 based on the sizes of the two index images. Note that the number of indexes used is not limited to two, and may be three or more.

[0133] If the dimensions of the two target images differ, the ophthalmologic observation device 1 of this example can determine, via the data processing unit 210, that the focus of the observation optical system 40 is deviated from the observation surface (the focus state is not good). Furthermore, the ophthalmologic observation device 1 of this example can perform focus adjustment by moving the surgical microscope 10 via control of the movement mechanism 70 by the main control unit 201. If a focus lens is provided in the observation optical system 40, the position of the focus lens can be adjusted. The data processing unit 210 can determine the movement direction of the surgical microscope 10 by determining the magnitude relationship between the two target images. Furthermore, the data processing unit 210 can determine the movement amount of the surgical microscope 10 based on the difference (difference, ratio, etc.) in the dimensions of the two target images. Based on the movement control information obtained in this manner, the main control unit 201 can control the movement mechanism 70. By repeating this series of processes, the focus of the observation optical system 40 can be guided to the observation surface, and this preferable focus state can be maintained.

[0134] In some aspects, the ophthalmic observation device 1 can execute the following processes: analyzing an observation image acquired by the surgical microscope 10 to detect multiple target images; calculating dimensions (e.g., diameter, circumference) of each detected target image; comparing the calculated dimensions of the multiple target images; determining movement control information (movement direction, movement amount) based on the result of this size comparison; and moving the surgical microscope 10 (or focus lens) based on the determined movement control information. In some aspects, the ophthalmic observation device 1 can repeatedly execute such a series of processes until the detected dimensions of the multiple target images satisfy a predetermined condition. For example, the ophthalmic observation device 1 can repeatedly execute the above series of processes until the dimensions of the multiple target images become equivalent (e.g., until the dimensions become equal or until the difference in dimensions becomes equal to or less than a predetermined threshold).

[0135] In some aspects, focus control can be performed in response to switching of the observation region. For example, the ophthalmologic observation device 1 further includes a mode switching unit for switching between a first observation mode for observing a first region of the subject's eye E and a second observation mode for observing a second region different from the first region. The control unit 200 and the data processing unit 210 (focus processing unit) are configured to perform detection of multiple target images and focus control in response to switching of the observation mode by the mode switching unit. According to such an aspect, switching of the observation mode can be used as a trigger to start autofocus in any of the above-mentioned aspects.

[0136] As described above, the first observation mode may be the anterior eye observation mode, and the second observation mode may be the posterior eye observation mode. In this case, the mode switching unit may include a front lens 21 that is inserted into the optical path to switch from the anterior eye observation mode to the posterior eye observation mode. The ophthalmic observation device 1 can start any of the above-mentioned autofocusing modes when triggered by the front lens 21 being inserted into the optical path. The ophthalmic observation device 1 can also start any of the above-mentioned autofocusing modes when triggered by the front lens 21 being retracted from the optical path.

[0137] Instead of or in addition to performing autofocus, the ophthalmologic observation device 1 can display information indicating the focus state acquired by the data processing unit 210. This allows the user to understand the current focus state from the displayed information.

[0138] Instead of or in addition to performing autofocus, the ophthalmic observation device 1 can display information indicating movement control information (movement direction, movement amount) acquired by the data processing unit 210. This allows the user to perform manual focus adjustment (fine adjustment, etc.) while referring to the displayed information. In other words, such an ophthalmic observation device 1 can support manual focus adjustment.

[0139] <Alignment> Some of the aspects of autofocus described above correspond to the alignment of the surgical microscope 10 in the Z direction. In addition, the ophthalmologic observation device 1 can align the surgical microscope 10 in the X and Y directions.

[0140] Conventionally, surgeons move the surgical microscope while referring to the observation image (for example, while observing the displayed image or while looking through the eyepiece to observe the subject's eye) to prevent unwanted light or dark areas from entering the field of view. This operation has been performed using a foot switch or a lever attached to the surgical microscope.

[0141] Below, several examples of alignment in the XY directions will be described. Note that it is possible to at least partially combine at least two of the several examples described below. Furthermore, in the following description, matters related to the ophthalmologic observation device 1 described above will be referred to as appropriate.

[0142] In the alignment in the XY directions, the illumination optical system 30 and the observation optical system 40 are at least partially moved in the XY directions. This movement is performed by the main control unit 201 controlling the movement mechanism 70.

[0143] In addition, when the front lens 21 is placed in the optical path, alignment is performed by moving the front lens 21, and when the front lens 21 is not placed in the optical path, alignment is performed by moving the objective lens 20.

[0144] More generally, the ophthalmic observation device 1 may be configured to perform alignment by any one of moving at least a part of the illumination optical system 30, moving at least a part of the observation optical system 40, moving the objective lens 20, and moving the front lens 21, or a combination of any two or more of these.

[0145] FIG. 7 shows a configuration example of a first mode for realizing auto-alignment in the XY directions. The data processing unit 210A of this example is an example of the data processing unit 210 and includes an abnormal image detection unit 211. The abnormal image detection unit 211 performs image analysis to detect abnormal images from images obtained by the observation optical system 40. Abnormal images are, for example, image regions with abnormally high brightness (for example, images of unnecessary light such as flare) and image regions with abnormally low brightness (dark areas). The abnormal image detection unit 211 may be configured to detect abnormal images by, for example, performing brightness threshold processing.

[0146] The control unit 200 (main control unit 201) and the data processing unit 210 act as a movement processing unit, and control the movement mechanism 70 based on the abnormal image detected by the abnormal image detection unit 211 to move the surgical microscope 10 in the X and Y directions.

[0147] The image 300 shown in FIG. 8 is a simplified illustration of an image containing an abnormal image. Reference numeral 301 denotes an abnormal image (flare or dark area) detected from the image 300 by the abnormal image detection unit 211. The data processing unit 210 can determine the movement direction based on the position of the abnormal image 301 in the image 300 (image frame). For example, in the image 300 of FIG. 8, an abnormal image is present in the upper left corner. In this case, the data processing unit 210 can set the movement direction to the direction toward the lower right corner. Typically, the data processing unit 210 can set the movement direction to the direction opposite to the direction in which the abnormal image is present as viewed from the center of the image. For example, the data processing unit 210 can perform a process of determining a representative point of the abnormal image, and a process of determining a vector starting from the representative point and ending at the center of the image, and set the direction of this vector as the movement direction. The representative point of the abnormal image may be, for example, the center of gravity or the position closest to the center of the image.

[0148] The data processing unit 210 can determine the amount of movement based on the dimensions of the abnormal image 301 in the image 300. For example, the data processing unit 210 can identify the position of the abnormal image closest to the image center, calculate a vector starting from the intersection of a line passing through the identified position and the image center with the frame edge and ending at the identified position, and set the magnitude of this vector (or greater) as the amount of movement. In this case, the direction of the vector can be set as the movement direction.

[0149] The main control unit 201 can align the surgical microscope 10 in the X and Y directions by controlling the movement mechanism 70 based on the movement control information (movement direction, movement amount) obtained by the data processing unit 210. Note that by repeatedly obtaining the movement control information and moving the surgical microscope 10, the optimal position in the X and Y directions can be searched for.

[0150] Compared to conventional manual alignment, this type of auto-alignment can reduce the amount of work required by the user, shorten the surgical time, and reduce the burden on the user and the patient.

[0151] A configuration example of a second aspect for realizing auto-alignment in the X and Y directions is shown in Fig. 9. A data processing unit 210B in this example is an example of the data processing unit 210, and includes a cropping processing unit 212 and an abnormal image detection unit 213.

[0152] The cropping processing unit 212 crops an area of predetermined dimensions (called a cropping target area) from the image obtained by the observation optical system 40. The dimensions of the cropping target area may be fixed or variable. Furthermore, the default position of the cropping target area may be fixed or variable. The main control unit 201 causes the display device 3 to display the image (partial image) cropped from the image obtained by the observation optical system 40.

[0153] The abnormal image detection unit 213 performs image analysis to detect an abnormal image from a partial image cropped from the image obtained by the observation optical system 40. The abnormal image detection unit 213 executes the same processing as the abnormal image detection unit 211 of the first example.

[0154] When the abnormal image detection unit 213 detects an abnormal image from a partial image, the cropping processing unit 212 moves a region of a predetermined size to a region of the image (the image acquired by the observation optical system 40) that does not include the detected abnormal image. Note that the cropping processing unit 212 may change the aspect (e.g., size, shape) of the cropping target region so that it does not include the detected abnormal image.

[0155] The image 310 shown in FIG. 10A is a simplified illustration of an image containing an abnormal image. The image 310 is an image acquired by the observation optical system 40 and shows the entire imaging area captured by the image sensor 62. Reference numeral 311 denotes an abnormal image mixed in the image 310. Reference numeral 312 denotes a cropping target area at the current stage. The cropping processing unit 212 crops the cropping target area 312 from the image 311 (referred to as a partial image 312). The abnormal image detection unit 213 performs image analysis to detect an abnormal image from the partial image 312. In the example shown in FIG. 10A, the partial image 312 includes a part of the abnormal image 311. In this case, the cropping processing unit 212 moves the cropping target area to a region of the partial image 312 that does not include the detected abnormal image. The process of determining the movement direction and amount may be performed in the same manner as in the first example. Alternatively, abnormal image detection may be applied to the entire image 311, and the results may be reflected in the movement of the cropping target area.

[0156] 10B shows the cropping target area 313 that has been moved by such auto-alignment. After the movement, the cropping target area 313 does not contain any abnormal images. Note that by repeatedly obtaining movement control information (movement direction, movement amount) and moving the cropping target area, it is possible to search for an optimal cropping target area.

[0157] Compared to conventional manual alignment, this type of auto-alignment can reduce the amount of work required by the user, shorten the surgical time, and reduce the burden on the user and the patient.

[0158] The present disclosure merely exemplifies embodiments, and any modifications, omissions, additions, substitutions, etc. can be made within the scope of the present disclosure and its equivalents. [Explanation of symbols]

[0159] 1. Ophthalmic observation device 2 Control device 3 Display device 10 Surgical microscope 30 Illumination optical system 35 Indicator member 40 Observation optical system 62 Image sensor 200 control section 201 Main control unit 210 Data Processing Unit 211, 213 Abnormal image detection unit 212 Cropping processing unit

Claims

1. an illumination system including a light source that emits illumination light and an index member having a plurality of indexes, and that projects the illumination light onto the subject's eye via the index member; an imaging system including an imaging element for capturing an image of the subject's eye; a focus processing unit that detects a plurality of target images from an image obtained by the imaging system and performs focus control of the imaging system based on the plurality of target images; Including, the plurality of indices include two indices arranged at positions separated from the observation surface by different optical distances from each other; Ophthalmic observation device.

2. one of the two targets is disposed on the side of the light source with respect to a position optically conjugate with the observation surface, and the other is disposed on the side of the eye to be examined with respect to the position optically conjugate with the observation surface; 2. The ophthalmologic observation device according to claim 1.

3. an illumination system including a light source that emits illumination light and an index member having a plurality of indexes, and that projects the illumination light onto the subject's eye via the index member; an imaging system including an imaging element for capturing an image of the subject's eye; a focus processing unit that detects a plurality of target images from an image obtained by the imaging system and performs focus control of the imaging system based on the plurality of target images; Including, At least two of the plurality of indices are provided on a plane-parallel plate that transmits the illumination light, the plurality of indices include a first indice provided on a first surface of the plane-parallel plate and a second indice provided on a second surface parallel to the first surface; Ophthalmic observation device.

4. a position optically conjugate with respect to the observation surface is disposed between the first surface and the second surface; 4. An ophthalmologic observation device according to claim 3.

5. the position optically conjugate with respect to the observation surface is disposed at a position equidistant from each of the first surface and the second surface; 5. An ophthalmologic observation device according to claim 4.

6. an illumination system including a light source that emits illumination light and an index member having a plurality of indexes, and that projects the illumination light onto the subject's eye via the index member; an imaging system including an imaging element for capturing an image of the subject's eye; a focus processing unit that detects a plurality of target images from an image obtained by the imaging system and performs focus control of the imaging system based on the plurality of target images; Including, the focus processing unit compares the dimensions of the plurality of target images and performs the focus control based on the result of the comparison. Ophthalmic observation device.

7. An objective lens, a first moving mechanism that moves the illumination system and the imaging system in a direction along the optical axis of the objective lens; Further comprising: The focus processing unit determining movement control information including at least one of a movement direction and a movement distance based on the result of the comparison; controlling the first movement mechanism based on the movement control information; 7. An ophthalmologic observation device according to claim 6.

8. the plurality of indices include a pair of indices having the same dimensions, each of which is disposed at two positions spaced apart by an equal optical distance in opposite directions along an optical axis of the illumination system from a position optically conjugate with respect to an observation plane; the focus processing unit performs the focus control so that the sizes of two target images corresponding to the pair of targets are equal to each other.

8. An ophthalmologic observation device according to claim 6 or 7.

9. an illumination system including a light source that emits illumination light and an index member having a plurality of indexes, and that projects the illumination light onto the subject's eye via the index member; an imaging system including an imaging element for capturing an image of the subject's eye; a focus processing unit that detects a plurality of target images from an image obtained by the imaging system and performs focus control of the imaging system based on the plurality of target images; An objective lens, a second moving mechanism that moves the illumination system and the imaging system in a direction perpendicular to the optical axis of the objective lens; an abnormal image detection unit that performs image analysis to detect abnormal images from the images obtained by the imaging system; a movement processing unit that controls the second movement mechanism based on the abnormal image when the abnormal image is detected by the abnormal image detection unit; Including, Ophthalmic observation device.

10. an illumination system including a light source that emits illumination light and an index member having a plurality of indexes, and that projects the illumination light onto the subject's eye via the index member; an imaging system including an imaging element for capturing an image of the subject's eye; a focus processing unit that detects a plurality of target images from an image obtained by the imaging system and performs focus control of the imaging system based on the plurality of target images; a cropping processing unit that crops an area of a predetermined size from the image obtained by the imaging system; an abnormal image detection unit that performs image analysis to detect abnormal images from partial images cropped from the image; Including, When the abnormal image is detected by the abnormal image detection unit, the cropping processing unit moves the region of the predetermined dimensions to a region of the image that does not include the detected abnormal image. Ophthalmic observation device.

11. an illumination system including a light source that emits illumination light and an index member having a plurality of indexes, and that projects the illumination light onto the subject's eye via the index member; an imaging system including an imaging element for capturing an image of the subject's eye; a focus processing unit that detects a plurality of target images from an image obtained by the imaging system and performs focus control of the imaging system based on the plurality of target images; a mode switching unit for switching between a first observation mode for observing a first region of the subject's eye and a second observation mode for observing a second region different from the first region; Including, the focus processing unit performs the detection of the target images and the focus control in response to the observation mode being switched by the mode switching unit, the first observation mode is an anterior ocular segment observation mode for observing an anterior ocular segment of the subject's eye, the second observation mode is a posterior segment observation mode for observing a posterior segment of the subject's eye, the mode switching unit includes a lens that is inserted into an optical path to switch from the anterior eye segment observation mode to the posterior eye segment observation mode. Ophthalmic observation device.

12. At least one of the plurality of indicators is disposed at a position spaced apart from the optical axis of the illumination system. An ophthalmologic observation device according to any one of claims 1 to 11.

13. the plurality of indices include at least two indices that are equidistant from the optical axis; 13. The ophthalmologic observation device of claim 12.

14. the at least two indices include two indices arranged symmetrically with respect to the optical axis in a direction perpendicular to the optical axis; 14. The ophthalmologic observation device of claim 13.

15. the focus processing unit performs the focus control based on blur of the plurality of target images. An ophthalmologic observation device according to any one of claims 1 to 14.

Images