JP2018110785A - Ophthalmic microscope and function expansion unit - Google Patents

Abstract

The present invention provides a new type of ophthalmic microscope that increases the degree of freedom in optical design in a Galileo type ophthalmic microscope equipped with an OCT optical system. The present invention relates to an illumination optical system (300), an observation optical system (400), an objective lens (2) through which an optical axis (O-400) of the observation optical system (400) is transmitted, and an OCT. In the ophthalmic microscope (1) having the optical system (500), the optical axis (O-500) of the OCT optical system does not pass through the objective lens (2), and the optical axis (O- 400) and the optical axis (O-500) of the OCT optical system are non-coaxial, the observation optical system (400), the objective lens (2), and the OCT optical system (500). An ophthalmic microscope (1) is provided, characterized in that it is arranged. [Selection] Figure 1

Description

The present invention relates to an ophthalmic microscope such as a fundus camera, a slit lamp, and an ophthalmic surgical microscope having an illumination optical system for illuminating a subject's eye and an observation optical system for observing the illuminated subject's eye. The ophthalmic microscope of the present invention has an OCT optical system capable of obtaining a tomographic image of an eye to be examined by optical coherence tomography (abbreviated as “OCT”), and includes an OCT optical system and an observation optical system. And can be made independent of each other, thereby increasing the degree of freedom in designing an ophthalmic microscope.
The present invention also relates to a function expansion unit that can be attached to and detached from an ophthalmic microscope and can add an OCT function to the ophthalmic microscope.

  An ophthalmic microscope is a medical or examination device that can illuminate a patient's eye to be examined with an illumination optical system, and enlarge and observe the eye to be examined with an observation optical system composed of a lens or the like. As such an ophthalmic microscope, a microscope capable of obtaining a tomographic image of an eye to be examined by having an OCT optical system has been developed.

OCT is a technique for obtaining a tomographic image of a living body by configuring an interferometer using a light source with low coherence (short coherence distance). Specifically, using a light source with low coherence, this light is divided into two by a beam splitter, and one light (measurement light) is irradiated to a living tissue to be reflected or scattered, and the other light (reference light). Is reflected by the mirror. The measurement light is reflected or scattered at various depths in the living tissue, and countless reflected or scattered light returns. When the measurement light that has returned to the beam splitter and the reflected light of the reference light are merged, only the reflected or scattered light of the measurement light that has passed through the same distance as the reference light is detected by interference with the reflected light of the reference light. . Therefore, the intensity of the measurement light reflected at various depths of the living tissue can be detected by adjusting the position of the beam splitter and the mirror to change the path length of the reference light in various ways. With such an OCT optical system, a tomographic image of a living tissue can be obtained.
By providing this OCT optical system in an ophthalmic microscope, it becomes possible to obtain tomographic images of the retina, cornea, iris, etc. of the eye, and it is possible to observe not only the surface of the tissue but also the internal state. Thereby, the diagnostic accuracy of the eye disease can be improved, and the success rate of ophthalmic surgery can be increased.

In an ophthalmic microscope having such an OCT optical system, it is necessary to incorporate the OCT optical system into a microscope having an illumination optical system and an observation optical system so that light from the OCT optical system can enter the eye to be examined. A method has been developed.
For example, a Galileo system having an observation optical system composed of an observation optical system for the left eye and an observation optical system for the right eye of the observer, and having one objective lens through which the optical axes of the left and right observation optical systems are transmitted in common In the ophthalmic microscope, there is a method in which the light of the OCT light source incident from the side of the objective lens is reflected by a reflecting member immediately above the objective lens and transmitted through the objective lens to be incident on the eye to be examined (Patent Document 1 and 2 etc.).

  More specifically, as shown in FIG. 12 (drawing with reference to FIG. 1 of Patent Document 1), the ophthalmic microscope includes an optical axis of the left-eye observation optical system and an optical axis of the right-eye observation optical system. The optical axis of the observation optical system composed of the left and right lens groups (130, 140, 150, 170, 180) that respectively transmit light, the optical axis of the left-eye observation optical system, and the optical axis of the right-eye observation optical system are common And an objective lens (110) that transmits light, an OCT optical system (200, 250, 450, 460, 470), and an illumination optical system (310, 320, 330). In the OCT optical system, the output light from the OCT light source (200) is emitted through the optical fiber (250), the direction is controlled by two scanning mirrors (450, 460), and then the beam combiner ( 340) is combined with the illumination light from the illumination optical system, is reflected by the beam splitter (120), and is incident on the eye to be examined (1000).

In addition, in a Galileo type ophthalmic microscope, there is a method in which light from an OCT light source is emitted from the upper part of an objective lens, transmitted through the objective lens, and incident on the eye to be examined (Patent Document 3).
Furthermore, in the Galileo ophthalmic microscope, there is a method in which the optical path of the OCT optical system is merged substantially coaxially with the optical path of the observation optical system, and is transmitted through the objective lens and incident on the eye to be examined (Patent Documents 4 and 5). ).

  In any of the above methods, the optical axis of the observation optical system and the optical axis of the OCT optical system are transmitted through one objective lens in common.

In the Galileo type ophthalmic microscope, as a method in which the optical axis of the OCT optical system does not pass through the objective lens, the light of the OCT light source incident from the side of the objective lens is reflected by a reflecting member directly under the objective lens, There is a method in which the light is incident on the eye without passing through the objective lens (Patent Document 6).
More specifically, as shown in FIG. 13 (drawing FIG. 2A of Patent Document 6), the side of the objective lens is located below the objective lens (102) through which the optical axis of the observation optical system is transmitted. The light from the OCT light source incident on the eye is reflected by the dichroic mirror (400), and the light from the OCT optical system is incident on the eye to be examined.
In this method, the optical path of the observation optical system and the optical path of the OCT optical system are concentrically joined directly below the objective lens.

Also, as a method different from the Galileo type ophthalmic microscope, there are two objective lenses corresponding to the left and right observation optical systems, respectively, and a Grino type ophthalmic use with a stereo angle between the left and right observation optical systems. There is a microscope (Patent Documents 7 and 8). In a Greenough-type ophthalmic microscope, there is no objective lens that transmits the optical axes of the left and right observation optical systems in common, so that the optical path of the OCT optical system is incident on the eye to be examined without passing through the objective lens. Can do.
However, in the Greenough-type ophthalmic microscope, the left and right observation optical systems are tilted with respect to each other to have a stereo angle, so that a complicated optical design is required.

JP-A-8-66421 JP 2008-264488 A JP 2008-268852 A Special table 2010-522020 gazette JP 2008-264490 A US Pat. No. 8,366,271 JP, 2006-185177, A JP, 2006-185178, A

As described above, conventional ophthalmic microscopes equipped with an OCT optical system include Galileo-type ophthalmic microscopes and Greenough-type ophthalmic microscopes, but Greenough-type ophthalmic microscopes require complicated optical designs. Met.
In the conventional Galileo type ophthalmic microscope, as shown in Patent Documents 1 to 5, etc., the optical axis of the observation optical system and the optical axis of the OCT optical system are transmitted through one objective lens in common. However, since the observation optical system and the OCT optical system are not independent, the OCT optical system and the observation optical system are affected by each other, and the degree of freedom in optical design is limited. Met.
In the conventional Galileo type ophthalmic microscope, as shown in Patent Document 6, a method in which the optical axis of the OCT optical system does not pass through the objective lens has been developed. However, the optical axis of the observation optical system and the OCT optical system are developed. In order to detect the reflected or scattered light of the OCT, an optical member for wavelength separation such as a wavelength separation filter or a beam splitter is provided. There was a problem that it was necessary. In addition, since the optical member of the OCT optical system is provided between the objective lens and the eye to be examined, there is a problem that a sufficient distance from the ophthalmic microscope to the eye to be examined cannot be secured.

  Therefore, in view of the above-described conventional situation, an object of the present invention is to develop a new type of ophthalmic microscope that increases the degree of freedom in optical design in a Galileo type ophthalmic microscope equipped with an OCT optical system.

  In order to solve the above-mentioned problems, the inventors of the present application have conducted intensive research. As a result, in the Galileo type ophthalmic microscope, the optical axis of the OCT optical system does not pass through the objective lens through which the optical axis of the observation optical system is transmitted. By arranging the optical axis of the optical system and the optical axis of the OCT optical system to be non-coaxial, the observation optical system and the OCT optical system are independent, and the degree of freedom in optical design is increased. Has been found to be detachable as a unit, and the present invention has been completed.

That is, this invention provides the following 1st invention regarding an ophthalmic microscope, the following 2nd invention regarding a function expansion unit, and the following 3rd invention regarding a function expansion set.
(1) 1st invention has the illumination optical system which illuminates the eye to be examined, the observation optical system for the left eye for observing the eye to be examined illuminated with the illumination optical system, and the observation optical system for the right eye An observation optical system, an objective lens through which the optical axis of the observation optical system for the left eye of the observation optical system and the optical axis of the observation optical system for the right eye transmit in common, and the eye to be examined by optical coherence tomography In an ophthalmic microscope having an OCT optical system for inspection,
The optical axis of the OCT optical system does not pass through the objective lens through which the optical axis of the observation optical system is transmitted, and the optical axis of the observation optical system and the optical axis of the OCT optical system are non-coaxial. The present invention relates to an ophthalmic microscope characterized in that the observation optical system, the objective lens, and the OCT optical system are arranged.
(2) In the first invention, the objective lens has a partial shape of a circular lens, or a shape in which a circular lens is provided with a notch or a hole,
It is preferable that the optical axis of the OCT optical system passes through a portion where the objective lens does not exist, or a notch or a hole provided in the objective lens.
(3) It is preferable that any one of the ophthalmic microscopes further includes an OCT objective lens that transmits the optical axis of the OCT optical system separately from the objective lens.
(4) In the case of (3) above, a circular lens or a lens composed of a circular lens portion is divided into two,
One of the divided lenses is the objective lens,
The other divided lens can be used as the OCT objective lens.
(5) It is preferable that any one of the ophthalmic microscopes further includes an objective lens position control mechanism for adjusting the position of the objective lens.
(6) In any one of the ophthalmic microscopes, it is preferable that the OCT optical system is detachably unitized.
(7) It is preferable that any one of the ophthalmic microscopes further includes a front lens that can be inserted and removed on an optical path between the eye to be examined and the objective lens in order to observe the retina of the eye to be examined.
(8) The second invention is an observation having an illumination optical system for illuminating the eye to be examined, an observation optical system for the left eye for observing the eye to be examined illuminated by the illumination optical system, and an observation optical system for the right eye Function expansion unit for use in an ophthalmic microscope having an optical system and an objective lens through which the optical axis of the observation optical system for the left eye of the observation optical system and the optical axis of the observation optical system for the right eye are transmitted in common In
A joint part detachable from the ophthalmic microscope;
An OCT optical system for inspecting the eye to be examined by optical coherence tomography,
When the function expansion unit is attached to the ophthalmic microscope via the joint portion, the optical axis of the OCT optical system does not pass through the objective lens through which the optical axis of the observation optical system passes, and the observation optical The present invention relates to a function expansion unit characterized in that the optical axis of the system and the optical axis of the OCT optical system are non-coaxial.
(9) The function expansion unit of the second invention preferably has an OCT objective lens through which the optical axis of the OCT optical system passes.
(10) It is preferable that any one of the function expansion units further includes a front lens that can be inserted into and removed from an optical path between the eye to be examined and the objective lens in order to observe the retina of the eye to be examined.
(11) A third invention provides a function expansion set including any one of the function expansion units and a replacement objective lens for replacing the objective lens.
(12) In the third invention, the replacement objective lens has a partial shape of a circular lens, or a shape in which a circular lens is provided with a notch or a hole,
When the objective lens is replaced with the replacement objective lens, and the function expansion unit is attached to the ophthalmic microscope via the joint portion,
It is preferable that the optical axis of the OCT optical system passes through a portion where the replacement objective lens does not exist, or a notch or a hole provided in the replacement objective lens.

In the ophthalmic microscope according to the first aspect of the invention, the optical axis of the OCT optical system does not pass through the objective lens through which the optical axis of the observation optical system passes, and the optical axis of the observation optical system and the optical axis of the OCT optical system are non-coaxial. It has become. With such a configuration, in the ophthalmic microscope of the present invention, the observation optical system and the OCT optical system are independent. For this reason, in the ophthalmic microscope of the present invention, since the observation optical system and the OCT optical system can be optically designed without being affected by each other, the ophthalmic microscope of the present invention has a degree of freedom in optical design. Has the effect of increasing.
The function expansion unit of the second invention and the function expansion set of the third invention are such that the optical axis of the OCT optical system of the function expansion unit does not transmit through the objective lens that transmits the optical axis of the observation optical system of the ophthalmic microscope. The optical axis of the observation optical system of the ophthalmic microscope is not coaxial with the optical axis of the OCT optical system of the function expansion unit. With such a configuration, the OCT optical system of the function expansion unit is independent of the observation optical system of the ophthalmic microscope, and can be unitized and has the effect of increasing the degree of freedom in optical design. In addition, since the function expansion unit can be attached to and detached from the ophthalmic microscope via the joint portion, the function expansion unit and the function expansion set of the present invention can easily add the function of OCT to the ophthalmic microscope. There is an effect.

BRIEF DESCRIPTION OF THE DRAWINGS It is drawing which shows typically the structure of an optical system about what was seen from the side about the ophthalmic microscope of the 1st Embodiment of this invention. It is drawing which shows typically the structure of an optical system about what was seen from the front about the ophthalmic microscope of the 1st Embodiment of this invention. It is drawing which shows typically the optical structure of the OCT unit used with the ophthalmic microscope of the 1st Embodiment of this invention. It is drawing which shows typically the shape of the objective lens used for the ophthalmic microscope of the 1st Embodiment of this invention. 4A is a view seen from the direction of the optical axis of the objective lens, and FIG. 4B is a view seen from the side. It is drawing which shows typically the shape of the objective lens used for the ophthalmic microscope of the 2nd Embodiment of this invention. FIG. 5A is a view seen from the direction of the optical axis of the objective lens, and FIG. 5B is a view seen from the side. It is drawing which shows typically the structure of an optical system as what was seen from the side about the ophthalmic microscope of the 2nd Embodiment of this invention. It is drawing which shows typically the shape of the objective lens used for the ophthalmic microscope of the 3rd Embodiment of this invention. FIG. 7A is a view seen from the direction of the optical axis of the objective lens, and FIG. 7B is a view seen from the side. It is drawing which shows typically the shape of the objective lens used for the ophthalmic microscope of the 4th Embodiment of this invention. FIG. 8A is a view seen from the direction of the optical axis of the objective lens, and FIG. 8B is a view seen from the side. It is drawing which shows typically the shape of the objective lens used for the ophthalmic microscope of the 5th Embodiment of this invention. FIG. 9A is a view seen from the direction of the optical axis of the objective lens, and FIG. 9B is a view seen from the side. It is drawing which shows typically the shape of the objective lens used for the ophthalmic microscope of the 6th Embodiment of this invention. FIG. 10A is a view seen from the direction of the optical axis of the objective lens, and FIG. 10B is a view seen from the side. It is drawing which shows typically the shape of the objective lens used for the ophthalmic microscope of the 7th Embodiment of this invention. FIG. 11A is a view seen from the direction of the optical axis of the objective lens, and FIG. 11B is a view seen from the side. It is drawing which quoted FIG. 1 of patent document 1. FIG. FIG. It is drawing which quoted 2A.

1. 1. Ophthalmic microscope 1-1. Overview of the Ophthalmic Microscope of the Present Invention An ophthalmic microscope of the present invention includes an illumination optical system that illuminates a subject eye, a left-eye observation optical system for observing the subject eye illuminated by the illumination optical system, and a right eye An observation optical system having an observation optical system, an objective lens in which the optical axis of the observation optical system for the left eye of the observation optical system and the optical axis of the observation optical system for the right eye are transmitted in common, and the eye to be examined by optical coherence tomography The present invention relates to an ophthalmic microscope having an OCT optical system for inspecting the above.

In the ophthalmic microscope of the present invention, the optical axis of the OCT optical system does not pass through the objective lens through which the optical axis of the observation optical system is transmitted, and the optical axis of the observation optical system and the optical axis of the OCT optical system are non-coaxial. As described above, the observation optical system, the objective lens, and the OCT optical system are arranged. With such a configuration, in the ophthalmic microscope of the present invention, the observation optical system and the OCT optical system are independent.
For this reason, in the ophthalmic microscope of the present invention, since the observation optical system and the OCT optical system can be optically designed without being affected by each other, the ophthalmic microscope of the present invention has a degree of freedom in optical design. Has the effect of increasing.
For example, although not limited to these, in addition to the objective lens of the observation optical system, an OCT objective lens is also provided in the OCT optical system, and the position of each objective lens is independently controlled, so that the observation optics Optical design is possible in which the focal point of the system and the focal point of the OCT optical system are adjusted independently. Further, an optical design in which the OCT optical system is separated from the observation optical system and the OCT optical system can be attached to and detached from the ophthalmic microscope is also possible. Furthermore, an optical design that can obtain a more detailed three-dimensional tomographic image by adding not only one OCT optical system to the ophthalmic microscope but also a plurality of OCT optical systems becomes possible.

  In the present invention, the term “ophthalmic microscope” refers to a medical or examination device that can enlarge and observe an eye to be examined, and includes not only humans but also animals. “Ophthalmic microscope” includes, but is not limited to, a fundus camera, a slit lamp, an ophthalmic surgical microscope, and the like.

In the present invention, the “illumination optical system” includes an optical element for illuminating the eye to be examined. The illumination optical system can further include a light source, but it may be one that guides natural light to the eye to be examined.
Further, in the present invention, the “observation optical system” is configured to include an optical element that makes it possible to observe the eye to be inspected by return light reflected and scattered from the eye to be inspected illuminated by the illumination optical system. Is. In the present invention, the observation optical system has a left-eye observation optical system and a right-eye observation optical system. When parallax is generated in an image obtained by the left and right observation optical systems, binocular vision is used. It is also possible to observe three-dimensionally.
In addition, the “observation optical system” of the present invention may be one capable of observing the subject's eye with the naked eye of an observer through an eyepiece, an eyepiece, or the like. It may be possible, or it may have both functions.

In the present invention, the “OCT optical system” includes an optical element that passes OCT measurement light or reference light. The OCT optical system can further include an OCT light source.
In the present invention, optical elements used in the “illumination optical system”, “observation optical system”, and “OCT optical system” are not limited to these. For example, lenses, prisms, mirrors, and optical filters are used. A diaphragm, a diffraction grating, a polarizing element, or the like can be used.

In the present invention, the “objective lens” refers to a lens provided on the eye side in an ophthalmic microscope. A front lens (loupe) that is temporarily inserted between the objective lens and the eye to be examined is not included in the “objective lens” in the present invention.
In the present invention, “the optical axis of the observation optical system and the optical axis of the OCT optical system are“ non-coaxial ”” means that the directions of the optical axes are not the same.

1-2. First Embodiment Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.
1 to 4 are drawings schematically showing a first embodiment which is an example of an ophthalmic microscope of the present invention. FIG. 1 is a schematic diagram showing the configuration of the optical system of the ophthalmic microscope according to the first embodiment as viewed from the side, and FIG. 2 is a schematic diagram as viewed from the front. FIG. 3 is a drawing schematically showing the optical configuration of the OCT unit, and FIG. 4 is a drawing schematically showing the shape of the objective lens.

As shown in FIG. 1, the optical system of the ophthalmic microscope (1) has an objective lens (2), an illumination optical system (300), an observation optical system (400), and an OCT optical system (500). doing.
The objective lens (2), the illumination optical system (300), and the observation optical system (400) are housed in the ophthalmic microscope main body (6). On the other hand, the OCT optical system (500) is accommodated in the function expansion unit (7). In FIG. 1, the ophthalmic microscope main body (6) and the function expansion unit (7) are indicated by alternate long and short dash lines.
The ophthalmic microscope main body (6) and the function expansion unit (7) are detachably connected by a joint portion (not shown).

  As shown in FIG. 1, the illumination optical system (300) illuminates the eye (8) through the objective lens (2). The illumination optical system (300) includes an illumination light source (9), an optical fiber (301), an exit aperture stop (302), a condenser lens (303), an illumination field stop (304), a collimator lens (305), and a reflection mirror ( 306). The optical axis of the illumination optical system (300) is indicated by a dotted line (O-300) in FIG.

The illumination light source (9) is provided outside the ophthalmic microscope body (6). One end of an optical fiber (301) is connected to the illumination light source (9). The other end of the optical fiber is disposed at a position facing the condenser lens (303) inside the ophthalmic microscope main body (6). The illumination light output from the illumination light source (9) is guided by the optical fiber (301) and enters the condenser lens (303).
An exit aperture stop (302) is provided at a position facing the exit port (fiber end on the condenser lens (303) side) of the optical fiber (301). The exit aperture stop (302) acts to block a partial region of the exit aperture of the optical fiber (301). When the blocking area by the exit aperture stop (302) is changed, the emission area of the illumination light is changed. Thereby, the irradiation angle by the illumination light, that is, the angle formed by the incident direction of the illumination light with respect to the eye to be examined (8) and the optical axis of the objective lens (2) can be changed.

The illumination field stop (304) is provided at a position (x position) optically conjugate with the front focal position (U0) of the objective lens (2). The collimating lens (305) converts the illumination light that has passed through the illumination field stop (304) into a parallel light flux. The reflection mirror (306) reflects the illumination light converted into a parallel light beam by the collimator lens (305) toward the objective lens (2). The reflected light passes through the objective lens (2) and is irradiated to the eye to be examined (8).
Illumination light (a part) irradiated to the eye to be examined (8) is reflected and scattered by the tissue of the eye to be examined such as cornea and retina. The reflected / scattered return light (also called “observation light”) passes through the objective lens (2) and enters the observation optical system (400).

As shown in FIG. 1, the observation optical system (400) includes a variable power lens system (401), a beam splitter (402), an imaging lens (403), an image erecting prism (404), and an eye width adjusting prism ( 405), a field stop (406), and an eyepiece lens (407). The optical axis of the observation optical system (400) is indicated by a dotted line (O-400) in FIG.
The observation optical system (400) is used for observing the eye to be examined (8) illuminated by the illumination optical system (300) through the objective lens (2).

As shown in FIG. 1, the OCT optical system (500) includes an OCT unit (10), an optical fiber (501), a collimating lens (502), an illumination field stop (509), an optical scanner (503a, 503b), and a relay. An optical system (504), a first lens group (505), a second lens group (506), and an OCT objective lens (507) are included.
The optical axis of the OCT optical system (500) is indicated by a dotted line (O-500) in FIG.
As shown in FIG. 1, in the first embodiment, the optical axis (O-500) of the OCT optical system does not pass through the objective lens (2), and the optical axis (O-400) of the observation optical system. ) And the optical axis (O-500) of the OCT optical system are non-coaxial, so that the OCT optical system and the observation optical system are independent.

  The OCT unit (10) divides light from an OCT light source having low coherence (short coherence distance) into measurement light and reference light. The measurement light is guided by the OCT optical system (500) and applied to the eye to be examined (8), and is reflected / scattered in the tissue of the eye to be examined, which is returned to the OCT unit (10). The OCT unit (10) detects interference between the return light of the measurement light and the reference light. Thereby, a tomographic image of the tissue of the eye to be examined can be obtained.

  As shown in FIG. 1, the OCT unit (10) is provided outside the function expansion unit (7), but one end of the optical fiber (501) is connected to the function expansion unit (7). ). The measurement light generated by the OCT unit (10) is emitted from the other end of the optical fiber (501). The emitted measurement light includes a collimating lens (502), an illumination field stop (509), an optical scanner (503a, 503b), a relay optical system (504), a first lens group (505), a second lens group (506), The return light of the measurement light irradiated to the eye to be examined (8) via the OCT objective lens (507), etc., and reflected / scattered by the tissue of the eye to be examined (8) travels in the opposite direction in the reverse direction. The light enters the other end of the fiber (501).

When observing the retina of the fundus, the front lens (14) is inserted on the optical axes O-300, O-400, and O-500 in front of the eye of the subject's eye by moving means (not shown). In this case, the front focal position (U0) of the objective lens (2) is conjugate with the retina of the fundus.
When observing the anterior segment of the cornea, iris, etc., observation is performed with the front lens detached from the front of the subject's eye.

As shown in FIG. 1, the collimating lens (502) converts the measurement light emitted from the other end of the optical fiber (501) into a parallel light flux. The collimating lens (502) and the other end of the optical fiber (501) are configured to be relatively movable along the optical axis of the measurement light. In the first embodiment, the collimator lens (502) is configured to be movable, but the other end of the optical fiber (501) may be configured to be movable along the optical axis of the measurement light.
The illumination field stop (509) is conjugate with the front focal position (U0) of the objective lens (2).

  Optical scanners (503a, 503b) in the OCT optical system deflect measurement light that has been converted into a parallel light beam by the collimator lens (502) in a two-dimensional manner. In the optical scanner (503a, 503b), a deflecting member configured to be rotatable about two axes intersecting each other is used. Examples of the deflecting member include a galvano mirror, a polygon mirror, a rotating mirror, and a MEMS (Micro Electro Mechanical Systems) mirror. In the first embodiment, the optical scanner (503a, 503b) includes a galvanometer mirror. In other words, the optical scanner has a first scanner (503a) having a deflection surface that can be rotated about a first axis, and a second scanner having a deflection surface that can be rotated about a second axis orthogonal to the first axis. A scanner (503b) is included. A relay optical system (504) is provided between the first scanner (503a) and the second scanner (503b).

The first lens group (505) includes one or more lenses. The second lens group (506) is also configured to include one or more lenses.
Further, an OCT objective lens (507) is provided on the side in contact with the eye to be examined (8).
The OCT objective lens is configured to be movable along the optical axis, and the focus of the OCT optical system can be adjusted by controlling the position of the OCT objective lens. Thereby, the focus of the OCT optical system can be adjusted to a position different from the focus of the observation optical system.

Thus, in the ophthalmic microscope of the first embodiment, the optical axis (O-500) of the OCT optical system does not pass through the objective lens (2), and the optical axis (O-400) of the observation optical system. And the optical axis (O-500) of the OCT optical system are non-coaxial, so that the observation optical system and the OCT optical system are independent.
For this reason, in the ophthalmic microscope of the first embodiment, the observation optical system and the OCT optical system can be controlled independently, and the OCT optical system can be attached to and detached from the ophthalmic microscope. It is also possible to do.

The ophthalmic microscope according to the first embodiment will be further described in detail with reference to the drawings.
FIG. 2 is a schematic diagram illustrating the configuration of the optical system of the ophthalmic microscope according to the first embodiment as viewed from the front.
As shown in FIG. 2, the observation optical system is divided into an observation optical system (400L) for the left eye of the observer and an observation optical system (400R) for the right eye, each having an observation optical path. Yes. The optical axes of the left and right observation optical systems are indicated by dotted lines (O-400L, O-400R) in FIG.

As shown in FIG. 2, the left and right observation optical systems (400L, 400R) are respectively a variable magnification lens system (401), an imaging lens (403), an image erecting prism (404), and an eye width adjusting prism ( 405), a field stop (406), and an eyepiece lens (407). The beam splitter (402) is included only in the observation optical system 400R for the right eye.
The variable magnification lens system (401) includes a plurality of zoom lenses (401a, 401b, 401c). Each zoom lens (401a, 401b, 401c) is movable along the optical axes (O-400L, O-400R) of the left and right observation optical systems by a zoom mechanism (not shown). Thereby, the magnification at the time of observing or photographing the eye to be examined (8) is changed.

As shown in FIG. 2, the beam splitter (402) of the right-eye observation optical system (400R) is a part of the observation light guided along the right-eye observation optical system from the eye to be examined (8). Is separated and guided to the photographing optical system. The photographing optical system includes an imaging lens (1101), a reflection mirror (1102), and a television camera (1103).
The television camera (1103) includes an image sensor (1103a). The image pickup element (1103a) is configured by, for example, a CCD (Charge Coupled Devices) image sensor, a CMOS (Complementary Metal Oxide Semiconductor) image sensor, or the like. An image sensor (1103a) having a two-dimensional light receiving surface (area sensor) is used.
When the ophthalmic microscope (1) is used, the light receiving surface of the imaging device (1103a) is disposed at a position optically conjugate with, for example, the cornea or retina surface of the eye to be examined (8).

The image erecting prism (404) converts the inverted image into an erect image. The eye width adjustment prism (405) is an optical element for adjusting the distance between the left and right observation optical paths in accordance with the eye width of the observer (the distance between the left eye and the right eye). The field stop (406) limits the observer's field of view by blocking the peripheral region in the cross section of the observation light. The field stop (406) is provided at a position (x position) conjugate with the front focal position (U0) of the objective lens (2).
The observation optical system (400L, 400R) may include a stereo variator configured to be detachable from the optical path of the observation optical system. The stereo variator is an optical axis position changing element for changing the relative positions of the optical axes (O-400L, O-400R) of the left and right observation optical systems respectively guided by the left and right variable magnification lens systems (401). is there. For example, the stereo variator is retracted to a retracted position provided on the observer side with respect to the observation optical path.

In the ophthalmic microscope of the first embodiment, in addition to the observation optical system used by the main observer, a sub-observation optical system (400S) for use by the assistant observer is provided.
As shown in FIG. 2, the sub-observation optical system (400S) passes the return light (observation light) reflected and scattered by the eye to be examined (8) illuminated by the illumination optical system via the objective lens (2). To the assistant eyepiece (411). The optical axis of the sub-observation optical system is indicated by a dotted line (O-400S) in FIG.
The sub-observation optical system (400S) is also provided with a pair of left and right optical systems, and stereoscopic observation with binocular is possible.

As shown in FIG. 2, the sub-observation optical system (400S) includes a prism (408), a reflection mirror (410), and an eyepiece for assistant (411). In the first embodiment, an imaging lens (409) is further disposed between the prism (408) and the reflection mirror (410). Observation light from the eye to be examined (8) passes through the objective lens (2) and is reflected by the reflecting surface (408a) of the prism (408). The observation light reflected by the reflecting surface (408a) passes through the imaging lens (409), is reflected by the reflecting mirror (410), and is guided to the assistant eyepiece lens (411).
The observation optical system (400L, 400R) and the sub-observation optical system (400S) are housed in the ophthalmic microscope main body (6).

When observing the retina of the fundus, the front lens (14) is inserted on the optical axes O-300, O-400, and O-500 in front of the eye of the subject's eye by moving means (not shown). In this case, the front focal position (U0) of the objective lens (2) is conjugate with the retina of the fundus.
When observing the anterior segment of the cornea, iris, etc., observation is performed with the front lens detached from the front of the subject's eye.

FIG. 3 is a drawing schematically showing an optical configuration of the OCT unit (10) used in the ophthalmic microscope according to the first embodiment.
As shown in FIG. 3, the OCT unit (10) divides the light emitted from the OCT light source unit (1001) into measurement light (LS) and reference light (LR), and passes through another optical path (measurement light ( LS) and reference light (LR) constitute an interferometer that detects interference.
The OCT light source unit (1001) includes a wavelength scanning type (wavelength sweep type) light source capable of scanning (sweeping) the wavelength of emitted light, as in a general swept source type OCT apparatus. The OCT light source unit (1001) temporally changes the output wavelength at a near infrared wavelength that cannot be visually recognized by human eyes. The light output from the OCT light source unit (1001) is indicated by a symbol L0.

The light L0 output from the OCT light source unit (1001) is guided to the polarization controller (1003) by the optical fiber (1002) and its polarization state is adjusted. The polarization controller (1003) adjusts the polarization state of the light L0 guided in the optical fiber (1002), for example, by applying external stress to the looped optical fiber (1002).
The light L0 whose polarization state is adjusted by the polarization controller (1003) is guided to the fiber coupler (1005) by the optical fiber (1004), and is divided into measurement light (LS) and reference light (LR).

As shown in FIG. 3, the reference light (LR) is guided to the collimator (1007) by the optical fiber (1006) to become a parallel light beam. The reference light LR that has become a parallel light beam is guided to the corner cube (1010) via the optical path length correction member (1008) and the dispersion compensation member (1009). The optical path length correction member (1008) acts as a delay unit for matching the optical path lengths (optical distances) of the reference light (LR) and the measurement light (LS). The dispersion compensation member (1009) acts as a dispersion compensation means for matching the dispersion characteristics of the reference light (LR) and the measurement light (LS).
The corner cube (1010) folds the traveling direction of the reference light (LR) that has become a parallel light beam by the collimator (1007) in the reverse direction. The optical path of the reference light (LR) incident on the corner cube (1010) and the optical path of the reference light (LR) emitted from the corner cube (1010) are parallel. The corner cube (1010) is movable in a direction along the incident optical path and the outgoing optical path of the reference light (LR). By this movement, the length of the optical path (reference optical path) of the reference light (LR) is changed.

As shown in FIG. 3, the reference light (LR) passing through the corner cube (1010) is converged from the parallel light flux by the collimator (1011) via the dispersion compensation member (1009) and the optical path length correction member (1008). It is converted into a light beam, enters the optical fiber (1012), is guided to the polarization controller (1013), and the polarization state of the reference light (LR) is adjusted.
The polarization controller (1013) has the same configuration as the polarization controller (1003), for example. The reference light LR whose polarization state is adjusted by the polarization controller (1013) is guided to the attenuator (1015) by the optical fiber (1014), and the light quantity is adjusted under the control of the arithmetic control unit (12). The reference light (LR) whose light quantity is adjusted by the attenuator (1015) is guided to the fiber coupler (1017) by the optical fiber (1016).

  As can be understood from FIGS. 1 and 3, the measurement light (LS) generated by the fiber coupler (1005) is guided to the collimating lens (502) by the optical fiber (501). As shown in FIG. 1, the measurement light incident on the collimating lens (502) includes an optical scanner (503a, 503b), a relay optical system (504), a first lens group (505), and a second lens group (506). , And the OCT objective lens (507) to irradiate the eye to be examined (8). The measurement light is reflected and scattered at various depth positions of the eye to be examined (8). The backscattered light of the measurement light by the eye to be inspected (8) travels in the same direction as the forward path in the reverse direction, and is guided to the fiber coupler (1005) and passes through the optical fiber (1018) as shown in FIG. Then, the fiber coupler (1017) is reached.

  The fiber coupler (1017) combines (interferes) the measurement light (LS) incident through the optical fiber (1018) and the reference light (LR) incident through the optical fiber (1016). ) Generate interference light. The fiber coupler (1017) generates a pair of interference light (LC) by branching the interference light between the measurement light (LS) and the reference light (LR) at a predetermined branching ratio (for example, 50:50). . A pair of interference light (LC) emitted from the fiber coupler (1017) is guided to the detector (1021) by two optical fibers (1019, 1020), respectively.

  The detector (1021) has, for example, a pair of photodetectors that respectively detect a pair of interference lights (LC), and outputs a difference between detection results, thereby providing a balanced photodiode (hereinafter referred to as “BPD”). ). The detector (1021) sends the detection result (detection signal) to the arithmetic control unit (12). The arithmetic control unit (12), for example, forms a cross-sectional image by performing Fourier transform or the like on the spectrum distribution based on the detection result obtained by the detector (1021) for each series of wavelength scans (for each A line). To do. The arithmetic control unit (12) displays the formed image on the display unit (13).

  In this embodiment, a Michelson interferometer is used. However, for example, any type of interferometer such as a Mach-Zehnder type can be appropriately used.

FIG. 4 is a schematic diagram illustrating the shape of an objective lens used in the ophthalmic microscope according to the first embodiment. 4A is a view seen from the direction of the optical axis of the objective lens, and FIG. 4B is a view seen from the side.
As shown in FIG. 4A, the planar shape of the objective lens (2) is circular. In the microscope of the first embodiment, the optical path of the left-eye observation optical system (P-400L), the optical path of the right-eye observation optical system (P-400R), and the optical path of the illumination optical system (P-300). ) Are transmitted through different portions of the objective lens (2). Although not shown, the optical path of the sub-observation optical system passes through the vicinity of the optical path (P-400L) of the left-eye observation optical system.
Next, as shown in FIG. 4B, the side surface shape of the objective lens (2) is a convex shape, which is a convex lens.

1-3. Shape of Objective Lens As the objective lens used in the ophthalmic microscope of the present invention, a circular lens can be used as in the first embodiment.
However, in the present invention, it is preferable to reduce the angle formed by the optical axis of the OCT optical system and the optical axis of the observation optical system. For this purpose, an objective lens having a partial shape of a circular lens or a circular lens is used. It is preferable to use an objective lens having a shape provided with a notch or a hole.

In the present invention, the “partial shape of a circular lens” refers to a shape obtained by cutting off a part of a circular lens when viewed in plan from the optical axis direction of the lens, and is not limited to these. A lens cut into a semicircular shape, a sector shape, a rectangular shape, or the like can be used so that the optical path of the observation optical system for the eye and the optical path of the observation optical system for the right eye are transmitted.
Further, in the present invention, “a shape in which a circular lens is provided with a notch or a hole” means a shape in which a notch or a hole is provided in a plan view from the optical axis direction of the lens. Although not necessarily, for example, a lens having a shape in which a notch or a hole is provided in a portion through which the optical path of the OCT optical system transmits can be used.

By using the lens having such a shape, the optical path of the OCT optical system can pass through a portion where the cut lens is not present in the circular lens, or a notch or a hole provided in the lens. Thereby, the angle formed by the optical axis of the OCT optical system and the optical axis of the observation optical system can be reduced without the optical axis of the OCT optical system being transmitted through the objective lens.
In the present invention, the angle formed by the optical axis of the OCT optical system and the optical axis of the observation optical system (one of the optical axes of the left and right observation optical paths) is preferably 1 to 15 °, more preferably The angle is preferably 4 to 10 °, and more preferably 6 to 8 °.

In the ophthalmic microscope of the present invention, a circular lens or a lens composed of a circular lens portion is divided into two, and one of the divided lenses is used as an objective lens through which the optical axis of the observation optical system is transmitted. This lens can be an objective lens that transmits the optical axis of the OCT optical system.
Here, as the “lens composed of a circular lens portion”, a lens having the above-mentioned “circular lens partial shape” can be used.
If such a divided lens is used and the position can be independently controlled, the observation optical system and the OCT optical system can be controlled independently.

1-4. Second Embodiment Hereinafter, an example of another embodiment of the present invention will be described in detail with reference to the drawings.
5 and 6 are drawings schematically showing a second embodiment which is another example of the ophthalmic microscope of the present invention.
FIG. 5 is a schematic diagram illustrating the shape of an objective lens used in the ophthalmic microscope according to the second embodiment. FIG. 5A is a view seen from the direction of the optical axis of the objective lens, and FIG. 5B is a view seen from the side.
FIG. 6 is a schematic diagram illustrating the configuration of the optical system of the ophthalmic microscope according to the second embodiment as viewed from the side.

As shown in FIG. 5A, the objective lens (2) used in the second embodiment has a partial shape obtained by cutting out a part of a circular lens, and the optical path of the left-eye observation optical system ( P-400L), the optical path of the right-eye observation optical system (P-400R), and the optical path of the illumination optical system (P-300) pass through different portions of the objective lens (2). The optical path (P-500) of the OCT optical system passes through the vicinity of the objective lens (2).
As shown in FIG. 5B, the side surface shape of the objective lens (2) is a partial shape obtained by cutting off a part of the convex lens.

As shown in FIG. 6, in the ophthalmic microscope of the second embodiment, the objective lens housed in the microscope body (6) is replaced with the objective lens (2) having the shape shown in FIG. ing.
The OCT optical system (500) housed inside the function expansion unit (7) includes an OCT unit (10), an optical fiber (501), a collimator lens (502), an illumination field stop (509), an optical scanner (503a, 503b), a relay optical system (504), a first lens group (505), a second lens group (506), an OCT objective lens (507), and a reflection mirror (508). .
When the function expansion unit (7) is attached to the microscope body (6) via a joint portion (not shown), the OCT objective lens (507) and the reflection mirror (508) are the lenses of the objective lens (2). Is inserted into the upper part of the cut-out part. The light (0-500) of the OCT optical system is reflected by the reflection mirror (508), passes through the OCT objective lens (507), and is irradiated to the eye to be examined (8).

When observing the retina of the fundus, the front lens (14) is inserted on the optical axes O-300, O-400, and O-500 in front of the eye of the subject's eye by moving means (not shown). In this case, the front focal position (U0) of the objective lens (2) is conjugate with the retina of the fundus.
When observing the anterior segment of the cornea, iris, etc., observation is performed with the front lens detached from the front of the subject's eye.

  In the second embodiment, the angle formed by the optical axis of the OCT optical system and the optical axis of the observation optical system can be reduced as compared with the first embodiment.

1-5. Third Embodiment FIG. 7 shows the shape of an objective lens used in a third embodiment, which is another example of the ophthalmic microscope of the present invention. FIG. 7A is a view seen from the direction of the optical axis of the objective lens, and FIG. 7B is a view seen from the side.
As shown in FIG. 7A, the objective lens (2) used in the third embodiment has a shape in which a cutout is provided in a part of a circular lens. The optical path (P-500) of the OCT optical system passes through the notch.

1-6. Fourth Embodiment FIG. 8 shows the shape of an objective lens used in a fourth embodiment which is another example of the ophthalmic microscope of the present invention. FIG. 8A is a view seen from the direction of the optical axis of the objective lens, and FIG. 8B is a view seen from the side.
As shown in FIG. 8A, the objective lens (2) used in the fourth embodiment has a shape obtained by cutting a part of a circular lens into a rectangular shape. The optical path (P-400L) and the optical path (P-400R) of the right-eye observation optical system are transmitted through different portions of the objective lens (2). The optical path (P-500) of the OCT optical system and the optical path (P-300) of the illumination optical system pass through the vicinity of the objective lens (2).
Further, as shown in FIG. 8B, the side shape of the objective lens (2) is a partial shape obtained by cutting off a part of the convex lens.

1-7. Fifth Embodiment FIG. 9 shows the shape of an objective lens used in a fifth embodiment, which is another example of the ophthalmic microscope of the present invention. FIG. 9A is a view seen from the direction of the optical axis of the objective lens, and FIG. 9B is a view seen from the side.
As shown in FIG. 9A, the objective lens (2) used in the fifth embodiment has a shape obtained by cutting a part of a circular lens into a semicircular shape, and the left-eye observation optical system. The optical path (P-400L), the optical path (P-400R) of the right-eye observation optical system, and the optical path (P-300) of the illumination optical system are transmitted through different portions of the objective lens (2). The optical path (P-500) of the OCT optical system passes through the vicinity of the objective lens (2).
Further, as shown in FIG. 9B, the side surface shape of the objective lens (2) is a partial shape obtained by cutting off a part of the convex lens.

1-8. Sixth Embodiment FIG. 10 shows the shape of an objective lens used in a sixth embodiment, which is another example of the ophthalmic microscope of the present invention. FIG. 10A is a view seen from the direction of the optical axis of the objective lens, and FIG. 10B is a view seen from the side.
As shown in FIG. 10A, the objective lens (2) used in the sixth embodiment has a shape in which a part of a circular lens is cut out in a crescent shape, and the objective optical system for the left eye is used. The optical path (P-400L), the optical path (P-400R) of the observation optical system for the right eye, and the optical path (P-300) of the illumination optical system are transmitted through different portions of the objective lens (2). The optical path (P-500) of the OCT optical system passes through the vicinity of the objective lens (2).
Further, as shown in FIG. 10B, the side shape of the objective lens (2) is a partial shape obtained by cutting off a part of the convex lens.

1-9. Seventh Embodiment FIG. 11 shows the shape of an objective lens used in a seventh embodiment, which is another example of the ophthalmic microscope of the present invention. FIG. 11A is a view seen from the direction of the optical axis of the objective lens, and FIG. 11B is a view seen from the side.
As shown in FIG. 11A, the objective lens (2) used in the seventh embodiment has a shape in which a hole (201) is provided in the center of a circular lens. The optical path (P-500) of the OCT optical system passes through the hole.
By providing a hole in this way, it is possible to irradiate the OCT optical system from the center of the objective lens without passing through the objective lens.

2. Function expansion unit The function expansion unit of the present invention can be attached to and detached from an ophthalmic microscope, and can add an OCT function to an ophthalmic microscope.
The function expansion unit of the present invention includes an illumination optical system that illuminates an eye to be examined, and an optical path of an observation optical system for a left eye and an optical path of an observation optical system for a right eye for observing the eye to be examined illuminated by the illumination optical system And an objective lens through which the optical axis of the observation optical system for the left eye of the observation optical system and the optical axis of the observation optical system for the right eye transmit in common are used. Is.
And the function expansion unit of the present invention comprises a joint part that can be attached to and detached from the ophthalmic microscope,
An OCT optical system for inspecting the eye to be examined by optical coherence tomography,
When the function expansion unit is attached to the ophthalmic microscope via the joint portion, the optical axis of the OCT optical system does not pass through the objective lens through which the optical axis of the observation optical system passes, and the observation optical The optical axis of the system and the optical axis of the OCT optical system are non-coaxial.

  The OCT optical system of the function expansion unit of the present invention is independent of the observation optical system of the ophthalmic microscope, and can be unitized and has the effect of increasing the degree of freedom in optical design. In addition, since the function expansion unit of the present invention can be attached to and detached from the ophthalmic microscope via the joint portion, there is an effect that the OCT function can be easily added to the ophthalmic microscope.

  The “joint part” of the function expansion unit of the present invention is not particularly limited as long as it allows the function expansion unit and the ophthalmic microscope to be attached and detached. It can be set as the joint part connected by matching, and the joint part connected using a screw | thread.

  A specific example of the function expansion unit of the present invention is the function expansion unit (enclosed by a one-dot chain line indicated by reference numeral 7 in FIGS. 1 and 6) in the ophthalmic microscope of the first embodiment and the ophthalmic microscope of the second embodiment. As described in (1).

3. Function expansion set The function expansion set of the present invention is the above-mentioned 2. And a replacement objective lens for replacing the objective lens of the ophthalmic microscope, and these are a set.
Here, as the replacement objective lens, 1-3. Can be used.
As a specific example of the replacement objective lens, the objective lenses (FIGS. 5 and 7 to 11) used in the second to seventh embodiments can be used.

  The function expansion set of the present invention has an effect that the function expansion unit can be attached to and detached from the ophthalmic microscope via the joint portion, so that the OCT function can be easily added to the ophthalmic microscope.

  The ophthalmic microscope, function expansion unit, and function expansion set of the present invention are useful in the industry for manufacturing ophthalmic medical devices.

The reference numerals used in FIGS. 1 to 11 indicate the following.
DESCRIPTION OF SYMBOLS 1 Ophthalmic microscope 2 Objective lens 300 Illumination optical system 301 Optical fiber 302 Output light aperture 303 Condenser lens 304 Illumination field aperture 305 Collimating lens 306 Reflection mirror 400 Observation optical system 400L Observation optical system 400R for the left eye Observation optical for the right eye System 400S sub-observation optical system 401 zoom lens system 401a, 401b, 401c zoom lens 402 beam splitter 403 imaging lens 404 image erecting prism 405 eye width adjustment prism 406 field stop 407 eyepiece lens 408 prism 408a prism reflecting surface 409 Image lens 410 Reflecting mirror 411 Assistant eyepiece 500 OCT optical system 501 Optical fiber 502 Collimate lenses 503a and 503b Optical scanner 504 Relay optical system 505 First lens group 506 Second lens group 507 O CT objective lens 508 Reflective mirror 509 Illumination field stop 6 Ophthalmic microscope main body 7 Function expansion unit 8 Eye to be examined 9 Illumination light source 10 OCT unit 1001 OCT light source unit 1002 Optical fiber 1003 Polarization controller 1004 Optical fiber 1005 Fiber coupler 1006 Optical fiber 1007 Collimator 1008 Optical path length correction member 1009 Dispersion compensation member 1010 Corner cube 1011 Collimator 1012 Optical fiber 1013 Polarization controller 1014 Optical fiber 1015 Attenuator 1016 Optical fiber 1017 Fiber coupler 1018 Optical fiber 1019 Optical fiber 1020 Optical fiber 1021 Detector 1101 Imaging lens 1102 Reflective mirror 1103 Television camera 1103a Image sensor 12 Arithmetic control unit 13 Display unit 14 Front lens O-300 Optical axis O-400 of the illumination optical system Optical axis O-400L of the observation optical system Optical axis O-400R of the observation optical system for the left eye Optical axis O-400S of the observation optical system for the right eye Sub-observation Optical axis of optical system O-500 Optical axis of OCT optical system P-300 Optical path of illumination optical system P-400L Optical path of observation optical system for left eye P-400R Optical path of observation optical system for right eye P-500 OCT optical system Optical path L0 Light output from the OCT light source unit Interference light LS Measurement light LR Reference light U0 Front focal position

Claims (12)

An illumination optical system for illuminating the eye to be examined, an observation optical system having an observation optical system for the left eye and an observation optical system for the right eye for observing the eye illuminated by the illumination optical system, and the observation optical system An objective lens through which the optical axis of the observation optical system for the left eye and the optical axis of the observation optical system for the right eye transmit in common, and an OCT optical system for inspecting the eye to be examined by optical coherence tomography In an ophthalmic microscope having
The optical axis of the OCT optical system does not pass through the objective lens through which the optical axis of the observation optical system is transmitted, and the optical axis of the observation optical system and the optical axis of the OCT optical system are non-coaxial. An ophthalmic microscope comprising the observation optical system, the objective lens, and the OCT optical system. The objective lens has a partial shape of a circular lens, or a shape in which a circular lens has a notch or a hole,
2. The ophthalmic microscope according to claim 1, wherein an optical axis of the OCT optical system passes through a portion where the objective lens does not exist, or a notch or a hole provided in the objective lens.   The ophthalmic microscope according to claim 1, further comprising an OCT objective lens through which an optical axis of the OCT optical system is transmitted separately from the objective lens. Divide the lens consisting of a circular lens or a circular lens part into two parts,
One of the divided lenses is the objective lens,
The ophthalmic microscope according to claim 3, wherein the other divided lens is the OCT objective lens.   The ophthalmic microscope according to claim 1, further comprising an objective lens position control mechanism for adjusting a position of the objective lens or the OCT objective lens.   The ophthalmic microscope according to claim 1, wherein the OCT optical system is detachably unitized.   7. The apparatus according to claim 1, further comprising a front lens that can be inserted into and removed from an optical path between the eye to be examined and the objective lens in order to observe the retina of the eye to be examined. The ophthalmic microscope described. An illumination optical system for illuminating the eye to be examined, an observation optical system having an observation optical system for the left eye and an observation optical system for the right eye for observing the eye illuminated by the illumination optical system, and In the function expansion unit used for an ophthalmic microscope having an optical axis of the observation optical system for the left eye and an objective lens that transmits the optical axis of the observation optical system for the right eye in common,
A joint part detachable from the ophthalmic microscope;
An OCT optical system for inspecting the eye to be examined by optical coherence tomography,
When the function expansion unit is attached to the ophthalmic microscope via the joint portion, the optical axis of the OCT optical system does not pass through the objective lens through which the optical axis of the observation optical system passes, and the observation optical A function expansion unit, wherein the optical axis of the system and the optical axis of the OCT optical system are non-coaxial.   The function expansion unit according to claim 8, further comprising an OCT objective lens that transmits an optical axis of the OCT optical system.   The function expansion unit according to claim 8 or 9, further comprising a front lens that can be inserted into and removed from an optical path between the eye to be examined and the objective lens in order to observe the retina of the eye to be examined. .   A function expansion set comprising the function expansion unit according to claim 8 and a replacement objective lens for replacing the objective lens. The replacement objective lens has a partial shape of a circular lens, or a shape in which a circular lens has a notch or a hole,
When the objective lens is replaced with the replacement objective lens, and the function expansion unit is attached to the ophthalmic microscope via the joint portion,
12. The function expansion set according to claim 11, wherein the optical axis of the OCT optical system passes through a portion where the replacement objective lens does not exist, or a notch or a hole provided in the replacement objective lens. .