microscope

Abstract

To provide a microscope that can apply a transillumination light to an eye fundus of an examined eye without lowering luminous energy of illumination light applied in the examined eye.SOLUTION: A microscope includes: an illumination system having a first lighting optical axis, and applying an illumination light to an examined eye along the first lighting optical axis; and a photographing system having a first imaging element and an optical system for guiding a first returning light from the examined eye applied by the illumination light to the image surface of the first imaging element, and imaging the first returning light by the first imaging element. The microscope is provided in which shine-proof conditions are satisfied by a material surface comprising the first lighting optical axis, the main surface of the optical system, and an image surface. The microscope includes: a transillumination optical system having a second lighting optical axis unlike the first lighting optical axis, and applying the transillumination light to the eye fundus of the examined eye along the second lighting optical axis; and an observation system for guiding the second returning light from the examined eye where the transillumination light is applied to the eye fundus to the second imaging element or the eye piece.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a microscope that functions as a Scheimpflug camera. [Background technology]

[0002] The slit lamp microscope described in Patent Document 1 is a Scheimpflug camera equipped with an illumination system and an imaging system including a lens system and an image sensor. These illumination system and imaging system are configured to satisfy the Scheimpflug condition, in which a plane including an object plane (a plane focused on an imaging plane described below) including the illumination optical axis of the illumination system, a plane including the principal plane of the lens system, and a plane including the imaging plane of the imaging element intersect on the same straight line. This allows imaging to be performed while focusing on all positions within the object plane. For example, the slit lamp microscope described in Patent Document 1 performs imaging while focusing on a cross section of the anterior segment of the eye to be examined (from the anterior surface of the cornea to the posterior surface of the crystalline lens).

[0003] In addition, the slit lamp microscope described in Patent Document 1 can generate a three-dimensional image of the anterior segment by continuously photographing cross sections of the anterior segment using the photographing system while moving the illumination system and the photographing system in a direction perpendicular to the object plane (illumination optical axis). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-213733 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when observing the condition of an intraocular lens implanted in a subject's eye or a lesion (such as cataract) in the subject's eye, a retroillumination optical system is generally used, which irradiates the fundus of the subject's eye with retroillumination light and illuminates the subject's eye from the back side (background illumination) using the fundus as a secondary light source. However, the slit lamp microscope described in Patent Document 1 does not have a retroillumination optical system. This makes it difficult to observe the intraocular lens, lesions, etc. using this slit lamp microscope.

[0006] Therefore, for example, it is conceivable to provide a retro-illumination optical system in the optical path of the illumination system of a slit lamp microscope. However, in this case, an optical element (such as a dichroic mirror) of the retro-illumination optical system must be provided in the optical path of the illumination system, which reduces the amount of illumination light (slit light) irradiated onto the subject's eye from the illumination system even when the retro-illumination optical system is not in operation. Because a large amount of light is required to photograph the subject's eye (cross section of the anterior segment) using a Scheimpflug camera, it is not desirable to provide an optical element of the retro-illumination optical system in the optical path of the illumination system.

[0007] The present invention has been made in consideration of the above circumstances, and its object is to provide a microscope that can irradiate retro-illumination light onto the fundus of the subject's eye without reducing the amount of illumination light irradiated onto the subject's eye. [Means for solving the problem]

[0008] A microscope for achieving the object of the present invention comprises an illumination system having a first illumination optical axis and irradiating an eye under examination with illumination light along the first illumination optical axis, a first image sensor, and an optical system that directs first return light from the eye under examination irradiated with the illumination light to the imaging surface of the first image sensor, and a photographing system that images the first return light using the first image sensor, in which the object plane including the first illumination optical axis, the main surface of the optical system, and the imaging surface satisfy the Scheimpflug condition, and further comprises a retro-illumination optical system having a second illumination optical axis different from the first illumination optical axis and irradiating the fundus of the eye under examination with retro-illumination light along the second illumination optical axis, and an observation system that directs the second return light from the eye under examination whose fundus is irradiated with retro-illumination light to the second image sensor or an eyepiece.

[0009] With this microscope, the optical elements of the observation system and the retro-illumination optical system are not arranged along the optical path of the illumination system, so that the illumination light irradiated from the illumination system onto the subject's eye is prevented from being vignetted by the optical elements, i.e., a reduction in the amount of illumination light is prevented.

[0010] In a microscope according to another aspect of the present invention, the second illumination optical axis is inclined with respect to the first illumination optical axis, and the inclination angle of the second illumination optical axis with respect to the first illumination optical axis is set to an angle at which the illumination light is not vignetted by the retro-illumination optical system, thereby preventing a decrease in the amount of illumination light.

[0011] In a microscope according to another aspect of the present invention, the observation system has a common observation optical axis with a part of the second illumination optical axis, and guides the second return light incident along the observation optical axis to the second image sensor or the eyepiece, thereby obtaining a good retro-illumination image even when the retro-illumination optical system is tilted with respect to the ocular axis of the subject's eye.

[0012] In a microscope according to another aspect of the present invention, the transillumination optical system irradiates the fundus with near-infrared transillumination light, thereby enabling a transillumination image of the subject's eye to be observed without using a mydriatic agent to dilate the pupil of the subject's eye.

[0013] In a microscope according to another aspect of the present invention, a moving mechanism is provided for moving the illumination system and the imaging system in a direction perpendicular to the object plane, and the positions of the retro-illumination optical system and the observation system are fixed.

[0014] In a microscope according to another aspect of the present invention, the illumination system irradiates the anterior segment of the subject's eye with slit-shaped illumination light.

[0015] In a microscope according to another aspect of the present invention, when the direction parallel to the first illumination optical axis is defined as the Z direction among the mutually orthogonal X, Y, and Z directions, the imaging optical axis of the imaging system is perpendicular to the Y direction and is inclined with respect to the first illumination optical axis when viewed from the Y direction, and the second illumination optical axis overlaps with the first illumination optical axis when viewed from the Y direction and is inclined with respect to the first illumination optical axis when viewed from the X direction. [Effects of the Invention]

[0016] The present invention can irradiate the fundus of the subject's eye with retro-illumination light without reducing the amount of illumination light irradiated onto the subject's eye. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 2 is a side view of the slit lamp microscope as seen from the X direction side. [Figure 2] FIG. 2 is a top view of the slit lamp microscope as seen from the Y direction side. [Figure 3] FIG. 2 is an explanatory diagram for explaining the configurations and arrangement conditions of an illumination system and an imaging system. [Figure 4] FIG. 1 is an explanatory diagram showing an example of a transillumination image obtained by photographing a test eye having an implanted intraocular lens using a slit lamp microscope, and an anterior segment cross-sectional image obtained by photographing the test eye using a Scheimpflug optical system. [Figure 5] FIG. 1 is an explanatory diagram showing an example of a transillumination image obtained by photographing a test eye having an implanted intraocular lens using a slit lamp microscope, and an anterior segment cross-sectional image obtained by photographing the test eye using a Scheimpflug optical system. [Figure 6] FIG. 1 is an explanatory diagram showing an example of a transillumination image obtained by photographing a test eye having an implanted intraocular lens using a slit lamp microscope, and an anterior segment cross-sectional image obtained by photographing the test eye using a Scheimpflug optical system. [Figure 7] FIG. 10 is an explanatory diagram for explaining a modified example of the observation system of the slit lamp microscope. DETAILED DESCRIPTION OF THE INVENTION

[0018] [Overall configuration of a slit lamp microscope] Fig. 1 is a side view of the slit lamp microscope 10 as viewed from the X direction. Fig. 2 is a top view of the slit lamp microscope 10 as viewed from the Y direction. Of the mutually orthogonal X, Y, and Z directions in the figure, the Z direction is a front-to-back direction (also called the working distance direction) parallel to the front direction approaching the subject's eye E and the rear direction away from the subject, the X direction is a left-to-right direction based on the subject, and the Y direction is a direction perpendicular to both the X and Z directions (here, the up-down direction).

[0019] 1 and 2, a slit lamp microscope 10 corresponds to the microscope of the present invention and has a mode for generating a three-dimensional image of the anterior segment Ea of the subject's eye E and a mode for capturing a transillumination image DS of the subject's eye E. This slit lamp microscope 10 mainly comprises a Scheimpflug optical system 12, a moving mechanism 14, an observation system 50, a transillumination optical system 60, and a control device 100.

[0020] [Scheimpflug optical system] The Scheimpflug optical system 12 is held so as to be movable in the X direction by a moving mechanism 14 (described later), and performs cross-sectional imaging along the YZ plane of the anterior segment Ea of the subject's eye E. The Scheimpflug optical system 12 is composed of an illumination system 20 and imaging systems 30R and 30L. Note that the imaging systems 30R and 30L are omitted from FIG. 1 to avoid complication of the drawing.

[0021] <Lighting> The illumination system 20 has a first illumination optical axis O1 parallel to the Z direction, and irradiates the anterior segment Ea of the subject's eye E with slit-shaped illumination light L (slit light LS) along this first illumination optical axis O1. The illumination system 20 may have a configuration similar to that of an illumination system of a conventional slit lamp microscope, and includes, for example, an illumination light source 22, a slit forming unit 24, and an objective lens 26, which are arranged along the first illumination optical axis O1.

[0022] The illumination light source 22 is, for example, an LED (light emitting diode), and emits illumination light L. Visible light is used as the illumination light L, but infrared light (near-infrared light) may also be used. The illumination light L emitted from the illumination light source 22 passes through a lens or the like (not shown), and then enters the slit forming portion 24. Furthermore, emission of the illumination light L from the illumination light source 22 is stopped when observing a retro-illumination image DS of the subject's eye E.

[0023] The illumination light source 22 may be composed of multiple light sources. For example, the illumination light source 22 may include a light source that outputs continuous light and an illumination light source that outputs flash light. The illumination light source 22 may also include an illumination light source for the anterior segment and an illumination light source for the posterior segment. Furthermore, the illumination light source 22 may include multiple light sources that output illumination light L with different wavelengths.

[0024] The slit forming unit 24 has, for example, a pair of slit blades parallel to the Y direction, and by changing the distance between these slit blades in the X direction (slit width), changes the width of the area through which the illumination light L passes. As a result, the illumination light L that has passed through the slit forming unit 24 becomes slit light LS whose width direction is the X direction and whose length direction is the Y direction at the anterior segment position when focused.

[0025] The length of the slit light LS in the Y direction is set to be equal to or greater than the diameter of the cornea on the surface of the anterior eye segment Ea. The slit forming unit 24 may be configured to be able to change the length of the slit light LS in the Y direction.

[0026] The objective lens 26 irradiates the anterior segment Ea with the illumination light L that has passed through the slit forming portion 24. As a result, the anterior segment Ea is irradiated with the slit light LS.

[0027] The illumination system 20 may further include a focusing optical system (not shown) for changing the focus position of the slit light LS.

[0028] <Photography> The imaging systems 30R and 30L capture images of the anterior segment Ea illuminated by the slit light LS from two different directions. The imaging systems 30R and 30L may have the same configuration as the imaging systems of conventional slit lamp microscopes. For example, the imaging system 30R includes an optical system 32R and an image sensor 34R arranged along the imaging optical axis O2R. The imaging system 30L also includes an optical system 32L and an image sensor 34L arranged along the imaging optical axis O2L.

[0029] The photographing optical axis O2R is parallel to the ZX plane and is inclined at an angle θR toward one side of the X direction with respect to the Z direction when viewed from the Y direction. The photographing optical axis O2L is parallel to the ZX plane and is inclined at an angle θL toward the other side of the X direction with respect to the Z direction when viewed from the Y direction. The angles θR and θL may be equal to or different from each other. The first illumination optical axis O1, the photographing optical axis O2R, and the photographing optical axis O2L intersect at a single point.

[0030] Although not shown, the optical system 32R includes, for example, an objective lens, a variable magnification optical system, and an imaging lens, in that order from the side closest to the subject's eye E. Return light LA ​​(corresponding to first return light) from the anterior eye segment Ea passes through the objective lens and variable magnification optical system of the optical system 32R, and is imaged on the imaging surface 36R of the image sensor 34R by the imaging lens of the optical system 32R. The optical system 32R may further include a focusing optical system (not shown).

[0031] The return light LA ​​from the anterior segment Ea includes the return light of the slit light LS irradiating the anterior segment Ea, and may also include other light. Examples of the return light LA ​​include reflected light, scattered light, and fluorescent light. Examples of other light include light from the installation environment of the slit lamp microscope 10 (room light, sunlight, etc.). If an anterior segment illumination system (not shown) for illuminating the entire anterior segment Ea is provided separately from the illumination system 20, the return light (reflected light) of the anterior segment illumination light from this anterior segment illumination system may be included in the "other light."

[0032] The image sensor 34R, together with the image sensor 34L described below, constitutes a first image sensor of the present invention. The image sensor 34R is a CMOS (complementary metal oxide semiconductor) or CCD (charge coupled device) area sensor having a two-dimensional image sensor surface 36R. The image sensor 34R captures an image of the return light LA ​​formed on the image sensor surface 36R by the optical system 32R, and outputs an anterior segment cross-sectional image DR to the control device 100. This anterior segment cross-sectional image DR is a captured image of the YZ cross section at the slit light irradiation position of the anterior segment Ea.

[0033] The optical system 32L has the same configuration as the optical system 32R described above, and although not shown, includes an objective lens, a variable magnification optical system, an imaging lens, etc., and may further include a focusing optical system. As a result, the return light LA ​​from the anterior segment Ea irradiated with the slit light LS passes through the objective lens and variable magnification optical system of the optical system 32L and is imaged on the imaging surface 36L of the image sensor 34L by the imaging lens of the optical system 32L.

[0034] The image sensor 34L is a CMOS or CCD area sensor having a two-dimensional image pickup surface 36L, and captures the returned light LA ​​formed on the image pickup surface 36L by the optical system 32L, and outputs an anterior eye segment cross-sectional image DL to the control device 100. This anterior eye segment cross-sectional image DL is a photographed image of the YZ cross section at the slit light irradiation position of the anterior eye segment Ea.

[0035] <Scheimpflug camera> 3 is an explanatory diagram for explaining the configuration and arrangement conditions of the illumination system 20 and the imaging systems 30R and 30L. As shown in FIG. 3, the illumination system 20 and the imaging system 30L function as a Scheimpflug camera, and the illumination system 20 and the imaging system 30R also function as a Scheimpflug camera.

[0036] As shown by reference numeral 3A in Figure 3, the illumination system 20 and the imaging system 30L are configured so that an object plane SP (a plane on which the imaging planes 36R and 36L are focused) that includes the first illumination optical axis O1 and is parallel to the YZ plane, a principal plane SL of the optical system 32L, and the imaging plane 36L satisfy the Scheimpflug condition (principle). More specifically, a plane H1 that includes the object plane SP, a plane H2L that includes the principal plane SL, and a plane H3L that includes the imaging plane 36L intersect on the same straight line. As a result, the imaging system 30L focuses on all positions within the object plane SP (for example, the range from the anterior surface of the cornea to the posterior surface of the lens of the anterior eye segment Ea) and captures the image, i.e., captures a cross-sectional image of the anterior eye segment Ea, thereby obtaining a cross-sectional image DL of the anterior eye segment.

[0037] Similarly, as shown by reference numeral 3B in Fig. 3, the illumination system 20 and the imaging system 30R are configured so that the object plane SP, the principal plane SR of the optical system 32R, and the imaging plane 36R satisfy the Scheimpflug condition. More specifically, the plane H1, the plane H2R including the principal plane SR, and the plane H3R including the imaging plane 36R intersect on the same straight line. As a result, the imaging system 30R also focuses on all positions within the object plane SP (the range from the anterior surface of the cornea to the posterior surface of the lens of the anterior eye segment Ea) and performs cross-sectional imaging of the anterior eye segment Ea, thereby obtaining a cross-sectional image DR of the anterior eye segment.

[0038] The configuration of the illumination system 20 and the imaging systems 30R, 30L that satisfies the Scheimpflug condition is realized by the configuration and arrangement of elements included in the illumination system 20, the configuration and arrangement of elements included in the imaging systems 30R, 30L, and the relative positions of the illumination system 20 and the imaging systems 30R, 30L. Parameters indicating the relative positions of the illumination system 20 and the imaging systems 30R, 30L include, for example, the above-mentioned angles θR, θL. The angles θR, θL are set to, for example, 17.5 degrees, 30 degrees, or 45 degrees. Note that the angles θR, θL may be variable.

[0039] [Moving mechanism] Although not shown, the moving mechanism 14 includes a stage on which the Scheimpflug optical system 12 is mounted and an actuator such as a motor for moving the stage at least in the X direction among the X, Y, and Z directions. The moving mechanism 14 moves the Scheimpflug optical system 12 in a direction perpendicular to the first illumination optical axis O1, more specifically, in the X direction, which is perpendicular to the object plane SP, in accordance with the illumination of the anterior eye segment Ea by the illumination system 20 with the slit light LS and the capture of the anterior eye segment cross-sectional images DR and DL by the imaging systems 30R and 30L. This allows the anterior eye segment Ea to be scanned in the X direction with the slit light LS parallel to the YZ plane, with the X direction being the width direction and the Y direction being the length direction. In this embodiment, the range of movement of the Scheimpflug optical system 12 in the X direction by the moving mechanism 14, i.e., the scanning range of the slit light LS in the X direction relative to the anterior eye segment Ea, is set to a range that includes at least the cornea of ​​the anterior eye segment Ea. Therefore, the entire cornea can be scanned with the slit light LS.

[0040] In this way, by scanning the anterior eye segment Ea in the X direction with the slit light LS from the illumination system 20 using the moving mechanism 14, the imaging systems 30R and 30L capture the returned light LA ​​(video imaging) and continuously output the anterior eye segment cross-sectional images DR and DL, whereby the anterior eye segment cross-sectional images DR and DL of the anterior eye segment Ea can be obtained for each scanning position of the slit light LS in the X direction (see Patent Document 1 above).

[0041] [Observation system] Returning to FIG. 1, the observation system 50 and the retro-illumination optical system 60 described below are provided independently of the Scheimpflug optical system 12, and their positions are fixed within the slit lamp microscope 10, i.e., their relative positions with respect to the subject's eye E are fixed.

[0042] The observation system 50 has an observation optical axis O3, and includes an optical system 52 and an image sensor 54 arranged along the observation optical axis O3 in this order from the side closest to the eye E to be examined.

[0043] The observation optical axis O3 (the same applies to a second illumination optical axis O3A described later) overlaps with the first illumination optical axis O1 when viewed from the Y direction, and is tilted downward in the Y direction (or upward in the Y direction) with respect to the first illumination optical axis O1 when viewed from the X direction by an inclination angle θ. This inclination angle θ is set to an appropriate angle, for example, approximately 8 degrees, so that the slit light LS irradiated from the illumination system 20 onto the anterior eye segment Ea is not vignetted by the observation system 50 and the retro-illumination optical system 60 described later. This prevents a decrease in the light intensity of the slit light LS irradiated from the illumination system 20 onto the anterior eye segment Ea.

[0044] The optical system 52 includes an imaging lens (not shown) and forms an image of the return light LB (corresponding to the second return light) from the subject's eye E on the imaging element 54. The optical system 52 may include a focusing optical system.

[0045] The return light LB from the subject's eye E includes return light (anterior segment reflected light) of the anterior segment illumination light irradiated onto the anterior segment Ea from the previously described anterior segment illumination system (not shown), and return light (fundus reflected light) of the retroillumination light LT irradiated onto the fundus Ef of the subject's eye E from the retroillumination optical system 60 described below.

[0046] The imaging element 54 corresponds to the second imaging element of the present invention, and is a CMOS or CCD type area sensor that captures the returned light LB formed by the optical system 52 and outputs an observation image of the subject's eye E (including the retroillumination image DS described below) to the control device 100.

[0047] [Transillumination optical system] The retro-illumination optical system 60 has a second illumination optical axis O3A that is common to a part of the observation optical axis O3 of the observation system 50, i.e., it is coaxial with the observation system 50. The second illumination optical axis O3A branches off from the observation optical axis O3 at a position midway, and the second illumination optical axis O3A is common to the observation optical axis O3 from this branching position to the subject's eye E. Note that instead of branching the second illumination optical axis O3A from a position midway from the observation optical axis O3, the observation optical axis O3 may be branched from a position midway from the second illumination optical axis O3A.

[0048] The retro-illumination optical system 60 includes a retro-illumination light source 62, a mirror 64, and a mirror 66 arranged along a second illumination optical axis O3A.

[0049] The transillumination light source 62 emits transillumination light LT (near-infrared light) in the near-infrared wavelength range. For example, a bullet-shaped LED that emits the transillumination light LT with narrow directivity is used as this transillumination light source 62. Note that an LED that emits the transillumination light LT with wide directivity may be used as the transillumination light source 62, and the transillumination light LT emitted from this LED may be converted into parallel light using a lens. The transillumination light LT emitted from the transillumination light source 62 is reflected by a mirror 64 toward a mirror 66. Note that the mirror 64 may be omitted and the transillumination light LT may be emitted directly from the transillumination light source 62 toward the mirror 66.

[0050] The mirror 66 is, for example, a dichroic mirror, and is disposed at a position where the second illumination optical axis O3A branches off from the observation optical axis O3. The mirror 66 reflects the retro-illumination light LT incident from the retro-illumination light source 62 via the mirror 64 toward the subject's eye E, and conversely, transmits the return light LB incident from the subject's eye E and emits it toward the optical system 52.

[0051] In this way, the trans-illumination optical system 60 irradiates the fundus Ef with trans-illumination light LT along the second illumination optical axis O3A. As a result, the trans-illumination light LT is diffusely reflected on the fundus Ef, and the fundus Ef serves as a secondary light source to provide background illumination to the crystalline lens of the subject's eye E from its back side. Return light LB from the background-illuminated subject's eye E passes through the mirror 66 and the optical system 52 and is incident on the image sensor 54, where it is imaged by the image sensor 54, thereby obtaining a trans-illumination image DS of the subject's eye E. Here, because the trans-illumination optical system 60 is coaxial with the observation system 50, a good trans-illumination image DS can be obtained even if the trans-illumination optical system 60 is inclined with respect to the ocular axis of the subject's eye E (here, the Z direction). The trans-illumination image DS output from the image sensor 54 is output to the control device 100.

[0052] The transillumination image DS is used to observe the misalignment (decentration) and edge of an intraocular lens 200 (see FIG. 4, etc.) such as an IOL (intraocular lens) or ICL (implantable collar lens) implanted in the subject's eye E, or to observe lesions that can be photographed with background illumination. If visible light is used as the transillumination light LT, the subject's eye E will constrict, making it difficult to observe the edge of the intraocular lens 200, and therefore it is necessary to use a mydriatic agent to open the pupil of the subject's eye E. In contrast, in this embodiment, near-infrared light is used as the transillumination light LT, which prevents the subject's eye E from constricting, making it possible to confirm the edge of the intraocular lens 200 without using a mydriatic agent.

[0053] [Control device] The control device 100 is equipped with an arithmetic circuit composed of various processors, memories, etc., and controls the overall operation of each part of the slit lamp microscope 10 based on operation instructions from the examiner input into an operation unit (not shown).

[0054] <3D image generation> When the control device 100 receives an instruction to generate a three-dimensional image of the anterior eye segment Ea as an operation instruction, it controls the movement mechanism 14 to align the Scheimpflug optical system 12 with the scanning start position (scan start position) of the slit light LS with respect to the anterior eye segment Ea. Note that this alignment may be performed manually by the examiner.

[0055] Next, the control device 100 controls the illumination light source 22, the image sensors 34R, 34L, and the movement mechanism 14 to successively perform the following operations: irradiating the anterior eye segment Ea with the slit light LS using the illumination system 20; capturing the returned light LA ​​using the imaging systems 30R, 30L and outputting the anterior eye segment cross-sectional images DR, DL; and scanning the slit light LS in the X direction using the movement mechanism 14. As a result, an area including at least the cornea of ​​the anterior eye segment Ea is scanned in the X direction with the slit light LS, and anterior eye segment cross-sectional images DR, DL are obtained for each scanning position of the slit light LS in the X direction. At this time, because the optical elements of the observation system 16 and the retro-illumination optical system 18 are not disposed in the optical path of the illumination system 20, vignetting of the slit light LS irradiated from the illumination system 20 to the anterior eye segment Ea by the optical elements, i.e., reduction in the light intensity of the slit light LS, is prevented.

[0056] The control device 100 then generates a three-dimensional image of the anterior eye segment Ea based on the anterior eye segment cross-sectional images DR and DL for each of the above-mentioned scanning positions. Note that the method for aligning the Scheimpflug optical system 12, the method for capturing the anterior eye segment cross-sectional images DR and DL using the Scheimpflug optical system 12 (the method for scanning the anterior eye segment using slit light LS), and the method for generating a three-dimensional image of the anterior eye segment Ea are publicly known technologies (see Patent Document 1 above), so detailed explanations will be omitted. The three-dimensional image of the anterior eye segment Ea generated by the control device 100 is output to a monitor connected to the control device 100, although not shown, or to an external display device via a communication network.

[0057] <Retroillumination photography> On the other hand, when the control device 100 receives an instruction to capture a retroillumination image DS of the subject's eye E as an operational instruction, it controls the movement mechanism 14 to align the observation system 16 and the retroillumination optical system 18 with respect to the subject's eye E. This alignment may also be performed manually by the examiner. Furthermore, when the control device 100 receives an instruction to capture a retroillumination image DS, it stops irradiating the anterior segment Ea with the slit light LS from the illumination system 20. This prevents the slit light LS from being included as noise in the retroillumination image DS.

[0058] Next, the control device 100 causes the transillumination light source 62 to emit the transillumination light LT, and also causes the observation system 50 to capture an image of the return light LB. This results in a transillumination image DS of the subject's eye E. Although not shown, this transillumination image DS is output by the control device 100 to a monitor, or to an external display device via a communication network.

[0059] 4 to 6 are explanatory diagrams showing an example of a transillumination image DS obtained by photographing the subject's eye E, into which an intraocular lens 200 has been implanted, using the slit lamp microscope 10 configured as described above, and anterior segment cross-sectional images DR and DL obtained by photographing the subject's eye E using the Scheimpflug optical system 12. Based on the transillumination image DS, it is possible to determine the positions of the mark 200a and hole 200b indicating the astigmatic axis direction of the intraocular lens 200 (ICL), as shown in FIG. 4, determine the position of the edge 200c of the intraocular lens 200, i.e., decentration, as shown in FIG. 5, and observe the diffraction grating of the intraocular lens 200, as shown in FIG. 6. This makes it possible to confirm the intraocular lens 200, which cannot be confirmed in the anterior segment cross-sectional images DR and DL, or to observe lesions (such as crystalline lens opacities) that can be observed with background illumination.

[0060] [Effects of this embodiment] As described above, in this embodiment, the slit lamp microscope 10 is provided with a retro-illumination optical system 60 that can irradiate the fundus Ef with retro-illumination light LT along the second illumination optical axis O3A, which is different from the first illumination optical axis O1 of the illumination system 20, thereby eliminating the need to place the optical elements of the retro-illumination optical system 60 in the middle of the optical path of the illumination system 20. As a result, in this embodiment, the fundus Ef can be irradiated with retro-illumination light LT without reducing the amount of slit light LS irradiated from the illumination system 20 to the anterior segment Ea.

[0061] [Modification of observation system] 7 is an explanatory diagram illustrating a modified example of the observation system 50 of the slit lamp microscope 10. In the above embodiment, the observation system 50 guides the returning light LB to the image sensor 54. However, the returning light LB may be guided to an eyepiece 59, that is, the examiner may observe the retro-illumination image DS through the eyepiece 59. In this case, as shown in FIG. 7, an eyepiece system 56 is provided in the observation system 50. This eyepiece system 56 includes a beam splitter 57, an imaging lens 58, and the eyepiece 59.

[0062] The beam splitter 57 is disposed on the observation optical axis O3, and transmits a portion of the return light LB from the subject's eye E to the optical system 52, and reflects the remainder toward the imaging lens 58. The imaging lens 58 guides the return light LB incident from the beam splitter 57 to the eyepiece 59. This allows the examiner to observe the retroillumination image DS through the eyepiece 59.

[0063] [others] In the above embodiment, the slit light LS parallel to the YZ plane is scanned in the X direction by moving the Scheimpflug optical system 12 in the X direction using the moving mechanism 14, but the length direction and scanning direction of the slit light LS can be changed as desired. Also, as described in Patent Document 1, the anterior segment Ea may be scanned with the slit light LS by rotating the Scheimpflug optical system 12 about the first illumination optical axis O1.

[0064] In the above embodiment, the anterior segment Ea is irradiated with the slit light LS, but the irradiation position of the slit light LS may be changed as appropriate within the subject's eye E. Also, in the above embodiment, the subject's eye E is irradiated with the slit light LS, but the subject's eye E may be irradiated with illumination light of various shapes other than the slit light LS.

[0065] In the above embodiment, the Scheimpflug optical system 12 is provided with two imaging systems 30R and 30L, but the number of imaging systems may be one or three or more.

[0066] In the above embodiment, the fundus oculi Ef is irradiated with near-infrared transillumination light LT from the transillumination optical system 60, but it may also be irradiated with visible transillumination light LT. [Explanation of symbols]

[0067] 10. Slit Lamp Microscope 12 Scheimpflug optics 14 Moving mechanism 16 Observation System 18 Transillumination optical system 20 Lighting System 22 Light source 24 Slit forming section 26 Objective Lens 30L, 30R photography system 32L,32R optical system 34L, 34R image sensor 36L, 36R imaging surface 50 Observation System 52 Optical system 54 Image sensor 56 Eyepiece system 57 Beam Splitter 58 Imaging Lens 59 Eyepiece 60 Transillumination optical system 62 Transillumination light source 64 Mirror 66 Mirror 100 control device 200 Intraocular Lenses 200a mark 200b hole 200c Edge DL Anterior segment cross-sectional image DR anterior segment cross-sectional image DS transillumination image E. Examined eye Ea anterior segment Ef fundus H1 plane H2L,H2R plane H3L,H3R plane L illumination light LA,LB Return light LS slit light LT Transillumination O1 First illumination optical axis O2L shooting optical axis O2R shooting optical axis O3 Observation optical axis O3A Second illumination optical axis SL main surface SP material SR main surface θ Tilt angle θL angle θR angle

Claims

1. an illumination system having a first illumination optical axis and irradiating an anterior segment of the eye to be examined with illumination light along the first illumination optical axis; an imaging system including a first image sensor and an optical system that guides first return light from the subject's eye illuminated with the illumination light to an imaging surface of the first image sensor, and that captures an image of the first return light using the first image sensor; Equipped with In a microscope, an object plane including the first illumination optical axis, a principal plane of the optical system, and the imaging plane satisfy the Scheimpflug condition, a retro-illumination optical system having a second illumination optical axis different from the first illumination optical axis, through which the illumination light does not pass, and irradiating the fundus of the eye to be examined with retro-illumination light along the second illumination optical axis without passing through an optical element arranged along the first illumination optical axis; an observation system that guides second return light from the subject's eye, the fundus of which is irradiated with the retro-illumination light, to a second image sensor or an eyepiece; A microscope equipped with:

2. the second illumination optical axis is inclined with respect to the first illumination optical axis, 2. The microscope according to claim 1, wherein an inclination angle of the second illumination optical axis with respect to the first illumination optical axis is set to an angle at which the illumination light is not vignetted by the retro-illumination optical system.

3. 3. The microscope according to claim 1, wherein the observation system has a common observation optical axis with a portion of the second illumination optical axis, and guides the second return light incident along the observation optical axis to the second imaging element or the eyepiece.

4. 4. The microscope according to claim 1, wherein the transillumination optical system irradiates the fundus with the transillumination light of near-infrared light.

5. a movement mechanism that moves the illumination system and the imaging system in a direction perpendicular to the object plane, 5. The microscope according to claim 1, wherein the positions of the retro-illumination optical system and the observation system are fixed.

6. 6. The microscope according to claim 1, wherein the illumination system irradiates the anterior segment of the subject's eye with the illumination light in a slit shape.

7. a direction parallel to the first illumination optical axis among X, Y, and Z directions which are orthogonal to each other is defined as a Z direction, and an imaging optical axis of the imaging system is perpendicular to a Y direction and is inclined with respect to the first illumination optical axis when viewed from the Y direction; 7. The microscope according to claim 1, wherein the second illumination optical axis overlaps with the first illumination optical axis when viewed from the Y direction and is tilted with respect to the first illumination optical axis when viewed from the X direction.

Images