Surgical microscope

Abstract

A surgical microscope comprises: an illumination optical system (32) that illuminates a patient's eye (E) with illumination light; and an observation optical system that guides, via an objective lens (20) and to an imaging device and / or an ocular lens, return light from the patient's eye illuminated with the illumination light. The illumination light axis (OS) of the illumination optical system is inclined with respect to the optical axis (OA) of the objective lens. The illumination optical system illuminates the patient's eye with the illumination light without the illumination light passing through the objective lens.

Description

surgical microscope

[0001] The present invention relates to a surgical microscope used in surgery on a patient's eye.

[0002] In cataract surgery, a cloudy lens is removed from a patient's eye (also referred to as the examinee's eye or the operated eye) and a replacement intraocular lens is inserted into the patient's eye. A surgical microscope is used for such cataract surgery (see Patent Document 1: JP 2021-129623 A). The surgical microscope described in Patent Document 1 includes an illumination optical system that irradiates the patient's eye with illumination light through an objective lens, and an imaging optical system that guides return light from the patient's eye through the objective lens to at least one of an eyepiece and an imaging element. This allows the surgeon to observe the patient's eye through the eyepiece, or to observe an image of the patient's eye displayed on a monitor.

[0003] Furthermore, in the surgical microscope described in Patent Document 1, in order to enable three-dimensional recognition of the patient's eye, the optical axis of the illumination optical system is tilted relative to the optical axis of the photographing optical system (objective lens), and illumination light is irradiated from the illumination optical system through the objective lens onto the patient's eye from an oblique direction.

[0004] During cataract surgery, after the anterior capsule of a patient's eye is incised and the crystalline lens is removed, the posterior capsule must be polished to ensure that no crystalline lens remains on the posterior side. To prevent rupture of the posterior capsule during this procedure, it is important to improve the visibility of the posterior capsule (the Y-shaped suture of the crystalline lens on the posterior side) using a surgical microscope. The surgical microscope described in Patent Document 1 improves the three-dimensional effect of the patient's eye by irradiating the patient's eye with illumination light from an illumination optical system through an objective lens from an oblique direction. While the anterior capsule (the Y-shaped suture of the crystalline lens on the anterior side) is visible, the visibility of the posterior capsule is insufficient. Therefore, further improvements in the visibility of the posterior capsule have been desired.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a surgical microscope that can improve the visibility of the posterior capsule.

[0006] The surgical microscope disclosed herein comprises an illumination optical system that irradiates illumination light onto a patient's eye, and an observation optical system that guides return light from the patient's eye irradiated with the illumination light through an objective lens to at least one of an imaging device or an eyepiece, wherein the illumination optical axis of the illumination optical system is inclined with respect to the optical axis of the objective lens, and the illumination optical system irradiates the illumination light onto the patient's eye without passing through the objective lens.

[0007] The surgical microscope of the present disclosure improves visibility of the posterior capsule.

[0008] FIG. 1 is a top view of a surgical microscope. FIG. 2 is a side view of the surgical microscope. FIG. 3 is an explanatory diagram for explaining the illumination angle and illumination distance of the second illumination optical system. FIG. 4 is an explanatory diagram for explaining the rotational angle position of the second illumination optical system. FIG. 5 is a diagram showing a Y-stitch on the crystalline lens, which serves as an indicator of the visibility of the posterior capsule. FIG. 6 is an explanatory diagram for explaining the relationship between the illumination angle and the visibility of the Y-stitch. FIG. 7 is an explanatory diagram for explaining the relationship between the illumination distance and the visibility of the Y-stitch. FIG. 8 is an explanatory diagram for explaining the relationship between the rotational angle position and the visibility of the Y-stitch. FIG. 9 is an explanatory diagram for explaining the range of rotational angle positions of the second illumination optical system as viewed from above. FIG. 10 is an explanatory diagram for explaining a more preferable range of rotational angle positions of the second illumination optical system as viewed from above. FIG. 11 is a diagram showing a modified example of the surgical microscope.

[0009] [Overall Configuration of Surgical Microscope] Figure 1 is a top view of a surgical microscope 10. Figure 2 is a side view of the surgical microscope 10. The Z direction in the figure is parallel to the up-down direction and corresponds to the working distance direction of the surgical microscope 10 (the direction of the optical axis OA of the objective lens 20, which will be described later). The X direction in the figure corresponds to the left-right direction (interpupillary distance direction) relative to the surgeon or patient (also referred to as the subject), and the Y direction is perpendicular to the XZ directions.

[0010] 1 and 2, a surgical microscope 10 is used for magnifying and observing a patient's eye E (also referred to as a subject) in a supine position during cataract surgery. The cataract surgery involves the steps of incising the anterior capsule CLa of the patient's eye E to remove the crystalline lens CL, polishing the posterior capsule CLb, and inserting an intraocular lens. The surgical microscope 10, which will be described in more detail below, improves the visibility of the posterior capsule CLb before and during cataract surgery.

[0011] The surgical microscope 10 includes an objective lens 20, a dichroic mirror DM, first illumination optical systems 31L and 31R, a second illumination optical system 32, an observation optical system 40, and an imaging device 60. The observation optical system 40 also includes a zoom expander 50. The objective lens 20 and the dichroic mirror DM may be included as part of the observation optical system 40. Although not shown, a front lens for fundus observation may be removably provided between the objective lens 20 and the patient's eye E.

[0012] The objective lens 20 has an optical axis OA parallel to the Z direction (working distance direction) and is disposed at a position facing the patient's eye E. A dichroic mirror DM and first illumination optical systems 31L and 31R are disposed above the objective lens 20 in the Z direction.

[0013] The dichroic mirror DM is provided between the objective lens 20 and the first illumination optical systems 31L, 31R at a position where the optical paths of the first illumination optical systems 31L, 31R can be coupled to the optical path of the observation optical system 40. The dichroic mirror DM transmits illumination light incident from the first illumination optical systems 31L, 31R and guides it to the objective lens 20. Furthermore, the dichroic mirror DM receives, via the objective lens 20, return light from the patient's eye E irradiated with illumination light from the first illumination optical systems 31L, 31R or return light from the patient's eye E irradiated with illumination light from the second illumination optical system 32. The dichroic mirror DM reflects the return light from the patient's eye E, which has entered through the objective lens 20, toward the observation optical system 40.

[0014] The first illumination optical systems 31L and 31R each emit illumination light with a wavelength in the visible region having a color temperature of, for example, 3000 K (Kelvin). As a result, the illumination light from the first illumination optical systems 31L and 31R is irradiated onto the patient's eye E via the dichroic mirror DM and the objective lens 20 (front lens).

[0015] Furthermore, the optical axis OL of the first illumination optical system 31L and the optical axis OR of the first illumination optical system 31R are arranged to be approximately coaxial with the optical axis OA of the objective lens 20. As a result, the first illumination optical systems 31L and 31R illuminate the fundus of the patient's eye E with so-called "0-degree illumination" via the dichroic mirror DM and the objective lens 20 (front lens). As a result, the illumination light is diffusely reflected on the fundus, allowing a retro-illumination image (red reflex) of the fundus to be stereoscopically photographed (observed).

[0016] The first illumination optical systems 31L and 31R can be omitted, in which case a reflecting mirror is disposed in place of the dichroic mirror DM.

[0017] The second illumination optical system 32 corresponds to the illumination optical system of the present disclosure. The second illumination optical system 32 has an illumination optical axis OS tilted with respect to the optical axis OA, and performs oblique illumination (angled illumination) in which illumination light is irradiated onto the patient's eye E from an oblique direction without passing through the objective lens 20. By performing oblique illumination, stereoscopic imaging of a predetermined portion of the patient's eye E (such as the crystalline lens CL and the posterior capsule CLb) can be performed while avoiding the influence of ghost images due to reflection from the cornea of ​​the patient's eye E. Furthermore, because the second illumination optical system 32 provides oblique illumination onto the patient's eye E without passing through the objective lens 20, the illumination angle ω, which is the tilt angle of the illumination optical axis OS with respect to the optical axis OA, can be made larger than in the prior art (see Patent Document 1) in which oblique illumination is performed via the objective lens 20.

[0018] The second illumination optical system 32 includes a light source 32 a and an illumination lens 32 b. The light source 32 a uses, for example, a bullet-shaped LED (Light Emitting Diode) and emits illumination light (white light) with a wavelength in the visible region having a color temperature of, for example, 4000 K to 6000 K. The illumination lens 32 b transmits the illumination light from the light source 32 a and irradiates the illumination light onto the patient's eye E without passing through the objective lens 20.

[0019] The position and orientation (illumination angle ω, illumination distance L and rotation angle position θ shown in FIGS. 3 and 4 described later) of the second illumination optical system 32 are adjusted within a range that can improve the visibility of the posterior capsule CLb, as will be described in detail later. Note that the second illumination optical system 32 is held by a holding unit (not shown) so that the above-mentioned position and orientation can be changed.

[0020] The observation optical system 40 has an observation optical axis OB parallel to the Y direction, and guides the return light from the patient's eye E, which has entered through the objective lens 20 and the dichroic mirror DM, to the imaging device 60. The observation optical system 40 includes an observation optical system 40L for the left eye and an observation optical system 40R for the right eye.

[0021] The left-eye observation optical system 40L includes a left-eye zoom expander 50L. The right-eye observation optical system 40R includes a right-eye zoom expander 50R. The left-eye zoom expander 50L includes multiple zoom lenses 51L, 52L, and 53L, and the right-eye zoom expander 50R includes multiple zoom lenses 51R, 52R, and 53R. Each of the zoom lenses 51L to 53L and each of the zoom lenses 51R to 53R can be moved in the optical axis direction of the observation optical axis OB by a magnification change mechanism (not shown).

[0022] The imaging device 60 captures an image of the return light from the patient's eye E, which is guided by the observation optical system 40. The imaging device 60 includes an imaging device 60L for the left eye and an imaging device 60R for the right eye.

[0023] The left-eye imaging device 60L includes an imaging lens 61L and an imaging element 62L. The imaging lens 61L forms an image of the returning light that has passed through the left-eye zoom expander 50L on the imaging surface of the imaging element 62L. The imaging element 62L is a two-dimensional area sensor. The imaging element 62L captures the returning light that has been imaged on its imaging surface and outputs an imaging signal.

[0024] The right-eye imaging device 60R includes an imaging lens 61R and an imaging element 62R. The imaging lens 61R forms an image of the returning light that has passed through the right-eye zoom expander 50R on the imaging surface of the imaging element 62R. The imaging element 62R is a two-dimensional area sensor. The imaging element 62R captures the returning light that has been imaged on its imaging surface and outputs an imaging signal.

[0025] Based on the imaging signals output from the left eye imaging device 60L and the right eye imaging device 60R, respectively, a control device (not shown) displays an observation image of the observed area of ​​the patient's eye E (e.g., the crystalline lens CL, the posterior capsule CLb) on a monitor (not shown).

[0026] It is also possible to provide a left eye eyepiece 64L instead of the left eye imaging device 60L, and a right eye eyepiece 64R instead of the right eye imaging device 60R. In this case, the surgeon observes the observation site of the patient's eye E through the left eye eyepiece 64L and the right eye eyepiece 64R. Furthermore, the surgical microscope 10 may be provided with both the left eye imaging device 60L and the right eye imaging device 60R and the left eye eyepiece 64L and the right eye eyepiece 64R.

[0027] [Second illumination optical system 32] Fig. 3 is an explanatory diagram for explaining the illumination angle ω and illumination distance L of the second illumination optical system 32. Fig. 4 is an explanatory diagram for explaining the rotation angle position θ of the second illumination optical system 32. Fig. 5 is a diagram showing the Y-shaped suture Sb of the crystalline lens CL, which serves as an indicator of the visibility of the posterior capsule CLb.

[0028] 3 and 4 , the position and orientation of the second illumination optical system 32 is adjusted within a range that can improve the visibility of the posterior capsule CLb before and during cataract surgery on the patient's eye E. The position and orientation of the second illumination optical system 32 include the illumination angle ω, illumination distance L, and rotation angle position θ of the second illumination optical system 32.

[0029] As described above, the illumination angle ω is the angle of the illumination optical axis OS with respect to the optical axis OA (see FIG. 3 ). The illumination distance L is the distance from the patient's eye E to the second illumination optical system 32 (e.g., the illumination lens 32 b) in the direction along the illumination optical axis OS (see FIG. 3 ).

[0030] The rotational angle position θ is the angular position of the second illumination optical system 32 (illumination lens 32b, etc.) in the XY plane in the direction around the optical axis OA (see FIG. 4). Here, when the optical axis OA is viewed from above in the Z direction, the side opposite to the direction in which the surgeon is located is set to θ=0°, the side in which the surgeon is located is set to θ=180°, the right side of the surgeon (right hand direction) is set to θ=90°, and the left side of the surgeon (left hand direction) is set to θ=270°.

[0031] The ranges of the illumination angle ω, illumination distance L, and rotation angle position θ of the second illumination optical system 32 that can improve the visibility of the posterior capsule CLb will be specifically described below. In this embodiment, the Y-shaped suture of the crystalline lens is used as an indicator of the visibility of the posterior capsule CLb. As shown in Fig. 5 , a Y-shaped suture Sa is formed on the anterior capsule CLa side of the crystalline lens CL, and a Y-shaped suture Sb is formed on the posterior capsule CLb side of the crystalline lens CL. The Y-shaped suture Sb serves as an indicator for the visibility of the posterior capsule CLb.

[0032] Fig. 6 is an explanatory diagram illustrating the relationship between the illumination angle ω and the visibility of the Y-shaped suture Sb. As shown in Fig. 6 and the previously described Fig. 3, the range of the illumination angle ω is set to 20°<ω<40°. Here, in the conventional technology (see Patent Document 1) in which oblique illumination is performed on the patient's eye E through an objective lens 20, the illumination angle ω increases only to approximately 5° to 6°, resulting in a small (deep) illumination angle ω. Therefore, in the conventional technology, the illumination light does not reach the scattering body of the posterior capsule CLb, making it difficult to see the Y-shaped suture Sb (posterior capsule CLb).

[0033] In contrast, the second illumination optical system 32 of this embodiment provides oblique illumination of the patient's eye E without the objective lens 20, allowing the illumination angle ω to be larger (shallower) than in the prior art. This allows the illumination light to reach the scattering bodies of the posterior capsule CLb, improving the visibility of the Y-shaped suture Sb, i.e., the visibility of the posterior capsule CLb. If the illumination angle ω is too large (shallow), the illumination light will hit the entire posterior capsule CLb, making it difficult to see part of the posterior capsule CLb. Although the visibility of the posterior capsule CLb is improved when the illumination angle ω is approximately 30°, it is necessary to consider variations in the patient's eye E. Therefore, in this embodiment, the range of the illumination angle ω is set to 20°<ω<40° based on the results of experiments or simulations.

[0034] FIG. 7 is an explanatory diagram illustrating the relationship between the illumination distance L and the visibility of the Y-shaped suture Sb. As shown in FIG. 7 and the previously described FIG. 3, the range of the illumination distance L is set to 130 mm<L<330 mm. If the illumination distance L is too long, i.e., if the second illumination optical system 32 is too far from the patient's eye E, the illumination light does not reach the posterior capsule CLb, making it difficult to see the Y-shaped suture Sb (posterior capsule CLb). Conversely, if the illumination distance L is too short, i.e., if the second illumination optical system 32 is too close to the patient's eye E, flare appears in the observation image, making it difficult to see the Y-shaped suture Sb (posterior capsule CLb). Therefore, in this embodiment, the range of the illumination distance L is set to 130 mm<L<330 mm based on the results of experiments or simulations.

[0035] The illumination distance L can be calculated from the equation L = h / (cos ω) based on the height distance h (also referred to as the height position, see FIG. 3 ) from the patient's eye E along the optical axis direction of the optical axis OA to the second illumination optical system 32 (illumination lens 32 b, etc.) and the illumination angle ω. Therefore, instead of determining the range of the illumination distance L, the range of the height distance h may be determined. In this case, for example, the height distance h can be set to a range from 150 mm to 250 mm.

[0036] Furthermore, when the distance from the optical axis OA to the second illumination optical system 32 (illumination lens 32b, etc.) along a direction perpendicular to the optical axis OA is defined as a vertical distance d (see FIG. 3), the illumination angle ω and the illumination distance L can be calculated based on the height distance h and the vertical distance d. Therefore, instead of determining the ranges of the illumination angle ω and the illumination distance L, the ranges of the height distance h and the vertical distance d may be determined.

[0037] Fig. 8 is an explanatory diagram illustrating the relationship between the rotation angle position θ and the visibility of the Y-shaped suture Sb. As shown in Fig. 8, by changing the rotation angle position θ of the second illumination optical system 32, the location where the illumination light is reflected in the scattering medium of the posterior capsule CLb, i.e., the location that is easily visible in the scattering medium, changes. Therefore, the optimal rotation angle position θ changes depending on which of the three suture lines that make up the Y-shaped suture Sb is being focused on. In this case, the rotation angle position θ is determined so that the illumination light is irradiated from a direction perpendicular to the extension direction of the suture line of interest.

[0038] Furthermore, if the rotation angle position θ of the second illumination optical system 32 is set in a certain angle range centered on the direction in which the surgeon is positioned, for example, 180°, this will hinder the surgeon from performing cataract surgery. For this reason, the range of the rotation angle position θ of the second illumination optical system 32 is determined taking into consideration the visibility of the posterior capsule CLb and the position of the surgeon (including an assistant; the same applies hereinafter).

[0039] Fig. 9 is an explanatory diagram illustrating the range of rotational angle positions θ of the second illumination optical system 32 as viewed from above. Fig. 10 is an explanatory diagram illustrating a more preferable range of rotational angle positions θ of the second illumination optical system 32 as viewed from above. Note that the symbol T in Figs. 9 and 10 represents the trajectory of the second illumination optical system 32 when the rotational angle position θ of the second illumination optical system 32 is changed from 0° to 360°. Furthermore, the symbol PA in Figs. 9 and 10 represents the allowable range of the rotational angle position θ, and the symbol FA represents the prohibitive range of the rotational angle position θ.

[0040] As shown in Fig. 9, as a result of experiments or simulations conducted in consideration of the visibility of the posterior capsule CLb and the position of the surgeon, the range of the rotational angle position θ of the second illumination optical system 32 is determined to be within a range excluding 120°≦θ≦240° (see prohibited range FA), i.e., within a range of -120° (240°) < θ < 120° (see permitted range PA). Furthermore, as shown in Fig. 10, it is more preferable to determine the range of the rotational angle position θ of the second illumination optical system 32 within at least one of the ranges of -30° (330°) < θ < 30°, 60° < θ < 120°, and 240° < θ < 300°.

[0041] As described above, the surgical microscope 10 of this embodiment can significantly improve the visibility of the posterior capsule CLb compared to conventional methods by adjusting the illumination angle ω, illumination distance L, and rotation angle position θ of the second illumination optical system 32 to the above-mentioned optimal ranges. In particular, in this embodiment, the second illumination optical system 32 provides oblique illumination to the patient's eye E without passing through the objective lens 20, so that a larger illumination angle ω can be ensured compared to conventional methods, thereby improving the visibility of the posterior capsule CLb.

[0042] [Modification] Figure 11 is a diagram showing a modification of the surgical microscope 10. While the second illumination optical system 32 of the surgical microscope 10 in the above embodiment has a linear illumination optical axis OS, this illumination optical axis OS may be bent. As shown in Figure 11, the modification of the surgical microscope 10 has basically the same configuration as the surgical microscope 10 in the above embodiment, except that it includes a second illumination optical system 36 instead of the second illumination optical system 32. For this reason, components that are identical in function or configuration to those in the above embodiment are designated by the same reference numerals, and their description will be omitted.

[0043] The illumination optical axis OS of the second illumination optical system 36 is bent in a direction perpendicular to the Z direction (up-down direction) and toward the optical axis OA (hereinafter referred to as the optical axis direction side) on the side opposite to the patient's eye E. The second illumination optical system 36 includes a light source 36a, a lens 36b, a filter 36c, and a reflecting mirror 36d, which are arranged along the side opposite to the optical axis direction side.

[0044] The light source 36a is, for example, a bullet-shaped LED similar to the light source 32a in the above embodiment, and emits the same illumination light as the light source 32a. The lens 36b is basically the same as the illumination lens 32b in the above embodiment, and transmits the illumination light incident from the light source 36a and emits it toward the filter 36c. The filter 36c adjusts the color of the illumination light.

[0045] The reflecting mirror 36d reflects the illumination light that has passed through the filter 36c and is incident thereon toward the patient's eye E without passing through the objective lens 20. This allows the second illumination optical system 36 to provide oblique illumination to the patient's eye E without passing through the objective lens 20.

[0046] The illumination angle ω of the second illumination optical system 36 is the angle of the illumination optical axis OS of illumination light directed from the reflecting mirror 36d to the patient's eye E relative to the optical axis OA. The illumination distance L of the second illumination optical system 36 is the distance from the patient's eye E to the reflecting mirror 36d in the direction along the illumination optical axis OS. The rotational angle position θ of the second illumination optical system 36 is the angular position of the reflecting mirror 36d in the XY plane in the direction around the optical axis OA. The ranges of the illumination angle ω, illumination distance L, and rotational angle position θ are adjusted to the same ranges as in the above embodiment. This achieves the same effects as in the above embodiment. Furthermore, by bending the illumination optical axis OS in the second illumination optical system 36, the surgical microscope 10 can be made smaller.

[0047] In the modified example of the surgical microscope 10 shown in Figure 11, the illumination optical axis OS of the second illumination optical system 36 is bent in one direction in the Y direction, but as long as the surgical microscope 10 can be made smaller, the bending direction of the illumination optical axis OS is not particularly limited, and the illumination optical axis OS may be bent in any direction, such as the X direction or the Z direction.

[0048] [Others] The configuration of the second illumination optical system 32, 36 constituting the surgical microscope 10 is not limited to the configurations shown in Figures 1 to 4 and 11 and can be modified as appropriate, as long as it is possible to provide oblique illumination of the patient's eye E without using the objective lens 20. Furthermore, the configuration of the observation optical system 40 is also not limited to the configuration shown in Figures 1 and 2 and can be modified as appropriate.

[0049] In the above embodiment, three parameters of the second illumination optical system 32 (similarly the second illumination optical system 36), namely, the illumination angle ω, the illumination distance L, and the rotation angle position θ, are adjusted, but it is also possible to adjust only one of the three parameters (for example, only the illumination angle ω, or only the illumination angle ω and the illumination distance L).

[0050] In the above embodiment, the optical axis OA of the objective lens 20 is parallel to the vertical direction, but the direction of this optical axis OA is not particularly limited, and it may be non-parallel to the vertical direction.

[0051] In the above embodiment, a surgical microscope 10 used to observe the posterior capsule CLb before and during cataract surgery was used as an example, but the present invention is applicable to various surgical microscopes 10 (excluding slit lamp microscopes) used to observe the posterior capsule CLb before and during various surgeries on a patient's eye E.

[0052] Some or all of the above-described embodiments can be described as, but are not limited to, the following supplementary notes.

[0053] [Supplementary Item 1] A surgical microscope comprising: an illumination optical system that irradiates illumination light onto a patient's eye; and an observation optical system that guides return light from the patient's eye irradiated with the illumination light through an objective lens to at least one of an imaging device or an eyepiece, wherein an illumination optical axis of the illumination optical system is inclined with respect to the optical axis of the objective lens, and the illumination optical system irradiates the illumination light onto the patient's eye without passing through the objective lens.

[0054] According to the surgical microscope described in Appendix 1, a large illumination angle, which is the inclination angle of the illumination optical axis relative to the optical axis of the objective lens, can be ensured, thereby improving the visibility of the posterior capsule.

[0055] [Supplementary Item 2] The surgical microscope according to Supplementary Item 1, wherein the optical axis of the objective lens is parallel to the vertical direction.

[0056] [Supplementary Item 3] The surgical microscope according to Supplementary Item 2, wherein, when a tilt angle of the illumination optical axis with respect to the optical axis of the objective lens is ω, the tilt angle is 20°<ω<40°, and when an illumination distance, which is the distance from the patient's eye to the illumination optical system, is L, the illumination distance is 130 mm<L<330 mm, and when a rotation angle position of the illumination optical system in a direction around the optical axis of the objective lens is θ, and when the direction opposite to the direction in which the surgeon is located when viewed from above in the up-down direction is θ=0°, the direction in which the surgeon is located when viewed from above is θ=180°, the right direction of the surgeon when viewed from above is θ=90°, and the left direction of the surgeon when viewed from above is θ=270°, the rotation angle position is within a range excluding 120°≦θ≦240°. This improves the visibility of the posterior capsule and prevents the illumination optical system from interfering with the surgeon's operation on the patient's eye.

[0057] [Supplementary Item 4] The surgical microscope according to Supplementary Item 3, wherein the rotation angle position is within at least one of the ranges of −30°<θ<30°, 60°<θ<120°, and 240°<θ<300°, thereby improving visibility of the posterior capsule and preventing the illumination optical system from interfering with the surgeon's surgery on the patient's eye.

[0058] [Supplementary Item 5] The surgical microscope according to any one of Supplementary Items 1 to 4, wherein the illumination optical axis is bent on the side opposite to the patient's eye side, thereby enabling the surgical microscope to be made smaller.

[0059] [Supplementary Item 6] The surgical microscope according to Supplementary Item 5, wherein the opposite side of the illumination optical axis is bent in a direction perpendicular to the up-down direction, thereby enabling the surgical microscope to be made smaller.

[0060] [Supplementary Item 7] The surgical microscope according to any one of Supplementary Items 1 to 6, which is used for observing the posterior capsule of a patient's eye during cataract surgery.

[0061] REFERENCE SIGNS LIST 10...surgical microscope 20...objective lens 31L, 31R...first illumination optical system 32...second illumination optical system 32a...light source 32b...illumination lens 36...second illumination optical system 36a...light source 36b...lens 36c...filter 36d...reflection mirror 40...observation optical system 40L...observation optical system for left eye 40R...observation optical system for right eye 50...zoom expander 50L...zoom expander for left eye 50R...zoom expander for right eye 51L to 53L...zoom lenses 51R to 53R...zoom lenses 60...imaging device 60L...imaging device for left eye 60R...imaging device for right eye 61L, 61R...imaging lens 62L, 62R...imaging element 64L, 64R...ocular lens for right eye CL...crystalline lens CLa...anterior capsule CLb...posterior capsule DM...Dichroic mirror E...Patient's eye FA...Prohibited range L...Lighting distance OA...Optical axis OB...Observation optical axis OL, OR...Optical axis OS...Illumination optical axis PA...Permitted range Sa, Sb...Y-shaped suture Y...Lens d...Vertical distance h...Height distance θ...Rotation angle position ω...Illumination angle

Claims

1. A surgical microscope comprising: an illumination optical system that irradiates a patient's eye with illumination light; and an observation optical system that guides return light from the patient's eye irradiated with the illumination light through an objective lens to at least one of an imaging device or an eyepiece, wherein the illumination optical axis of the illumination optical system is inclined with respect to the optical axis of the objective lens, and the illumination optical system irradiates the patient's eye with the illumination light without passing through the objective lens.

2. A surgical microscope according to claim 1, wherein the optical axis of the objective lens is parallel to the vertical direction.

3. The surgical microscope according to claim 2, wherein, when the tilt angle of the illumination optical axis with respect to the optical axis of the objective lens is ω, the tilt angle is 20°<ω<40°, and when the illumination distance, which is the distance from the patient's eye to the illumination optical system, is L, the illumination distance is 130 mm<L<330 mm, and when the rotation angle position of the illumination optical system in the direction around the optical axis of the objective lens is θ, the direction opposite to the direction in which the surgeon is located when viewed from above in the up-down direction is θ=0°, the direction in which the surgeon is located when viewed from above is θ=180°, the right direction of the surgeon when viewed from above is θ=90°, and the left direction of the surgeon when viewed from above is θ=270°, the rotation angle position is within the range excluding 120°≦θ≦240°.

4. A surgical microscope according to claim 3, wherein the rotation angle position is within at least one of the ranges of -30°<θ<30°, 60°<θ<120°, and 240°<θ<300°.

5. A surgical microscope according to any one of claims 2 to 4, wherein the illumination optical axis is bent on the side opposite to the patient's eye.

6. A surgical microscope according to claim 5, wherein the opposite side of the illumination optical axis is bent in a direction perpendicular to the up-down direction.

7. A surgical microscope according to any one of claims 1 to 4, which is used to observe the posterior capsule of a patient's eye during cataract surgery.

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