microscope

Abstract

To provide a microscope that allows a Scheimpflug optical system to be accurately aligned for an eye to be examined.SOLUTION: A microscope includes: a light flux projection system provided in an illumination system for projecting light fluxes different from illumination light onto an eye to be examined along an illumination light axis; an observation system for imaging the eye to be examined onto which light fluxes are projected by the light flux projection system in a direction different from a direction of the illumination light axis and a direction of an imaging light axis of an imaging system, and acquiring an observation image of the eye to be examined; a relative position detection part for detecting a relative position of the eye to be examined with respect to a Scheimpflug optical system on the basis of a Purkinje image included in the observation image acquired by the observation system; and an alignment control part for executing alignment of the Scheimpflug optical system for the eye to be examined on the basis of a result of the detection of the relative position by the relative position detection part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a microscope equipped with a Scheimpflug optical system. [Background technology]

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

[0003] In addition, the slit lamp microscope described in Patent Document 1 continuously photographs cross sections of the anterior eye segment using an imaging system while moving a Scheimpflug optical system in a direction perpendicular to the object plane (illumination optical axis), thereby scanning the entire cornea of ​​the anterior eye segment with slit light and acquiring a cross-sectional image of the anterior eye segment for each scanning position.The slit lamp microscope then generates a three-dimensional image of the anterior eye segment based on the cross-sectional image of the anterior eye segment for each scanning position. [Prior art documents] [Patent documents]

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

[0005] In order to generate a three-dimensional image of a desired three-dimensional region (including the entire region) of the anterior segment using the slit lamp microscope described in Patent Document 1, it is necessary to align the scanning range of the slit light and the photographing range of the cross section of the anterior segment to the three-dimensional region. To achieve this, it is necessary to precisely align the Scheimpflug optical system with the subject's eye before the start of scanning with the slit light.

[0006] The present invention has been made in view of the above circumstances, and has as its object to provide a microscope capable of aligning a Scheimpflug optical system with the subject's eye with high precision. [Means for solving the problem]

[0007] A microscope for achieving the object of the present invention includes an illumination system having an illumination optical axis and irradiating an eye to be examined with illumination light along the illumination optical axis, an imaging element, and an optical system that guides return light from the eye to be examined irradiated with the illumination light to an imaging surface of the imaging element, and an imaging system that images the return light with the imaging element, wherein an object plane including the illumination optical axis, a principal plane of the optical system, and the imaging surface satisfy the Scheimpflug condition, and the microscope further includes a relative movement mechanism that moves the Scheimpflug optical system including the illumination system and the imaging system relative to the eye to be examined, a light beam projection system that is provided in the illumination system and projects a light beam different from the illumination light onto the eye to be examined along the illumination optical axis, and a projection system that projects the light beam onto the eye to be examined by the light beam projection system. an illumination control unit that stops the illumination of the eye to be examined by the illumination system while the illumination is in progress; an observation system that acquires an observation image of the eye to be examined by photographing the eye to which the light beam is projected by the light beam projection system from a direction different from the direction of the illumination optical axis and the direction of the imaging optical axis of the imaging system; a relative position detection unit that detects the relative position of the eye to be examined with respect to the Scheimpflug optical system based on the Purkinje image included in the observation image acquired by the observation system; and an alignment control unit that automatically drives the relative movement mechanism based on the result of relative position detection by the relative position detection unit or drives the relative movement mechanism in response to manual operation, thereby aligning the Scheimpflug optical system with the eye to be examined.

[0008] This microscope allows alignment of the Scheimpflug optical system with the eye to be examined.

[0009] In a microscope according to another aspect of the present invention, when the direction parallel to the illumination optical axis among the mutually orthogonal X, Y, and Z directions is defined as the Z direction, the imaging optical axis is perpendicular to the Y direction and is inclined with respect to the illumination optical axis when viewed from the Y direction, and the observation optical axis of the observation system overlaps with the illumination optical axis when viewed from the Y direction and is inclined with respect to the illumination optical axis when viewed from the X direction.

[0010] In a microscope according to another aspect of the present invention, the inclination angle of the observation optical axis with respect to the illumination optical axis is set to an angle that prevents vignetting of the illumination light by the observation system, thereby preventing a decrease in the amount of illumination light irradiated from the illumination system onto the subject's eye.

[0011] In a microscope according to another aspect of the present invention, the position of the observation system is fixed.

[0012] A microscope for achieving the object of the present invention includes an illumination system having an illumination optical axis and irradiating an eye to be inspected with illumination light along the illumination optical axis, and a plurality of photographing systems for photographing the eye to be inspected illuminated with illumination light by the illumination system from different directions, the plurality of photographing systems including an optical system and an image sensor for capturing an image of return light from the eye to be inspected that has been imaged by the optical system, and in each photographing system, an object plane including the illumination optical axis, a principal plane of the optical system, and an image sensor surface satisfy the Scheimpflug condition. In this microscope, the microscope further includes a relative movement mechanism for moving the Scheimpflug optical system including the illumination system and the plurality of photographing systems relative to the eye to be inspected, and a light beam different from the illumination light that is projected along the illumination optical axis. The apparatus includes a light beam projection system that projects light onto the subject's eye, an illumination control unit that stops the illumination system from irradiating the subject's eye with illumination light while the light beam projection system is projecting the light beam onto the subject's eye, an imaging control unit that causes a plurality of imaging systems to photograph the subject's eye while the light beam projection system is projecting the light beam onto the subject's eye, a relative position detection unit that detects the relative position of the subject's eye with respect to the Scheimpflug optical system based on a Purkinje image included in the observation images of the subject's eye photographed by the plurality of imaging systems, and an alignment control unit that automatically drives a relative movement mechanism based on the relative position detection result by the relative position detection unit or drives the relative movement mechanism in response to manual operation, thereby aligning the Scheimpflug optical system with the subject's eye.

[0013] According to this microscope, the Scheimpflug optical system can be aligned with the subject's eye without providing a separate camera for alignment detection.

[0014] In a microscope according to another aspect of the present invention, the multiple imaging systems include a first imaging system and a second imaging system, and when the direction parallel to the illumination optical axis among the mutually orthogonal X, Y, and Z directions is defined as the Z direction, the imaging optical axis of the first imaging system is perpendicular to the Y direction and is inclined in one direction in the X direction with respect to the illumination optical axis when viewed from the Y direction, and the imaging optical axis of the second imaging system is perpendicular to the Y direction and is inclined in the other direction in the X direction with respect to the illumination optical axis when viewed from the Y direction.

[0015] A microscope according to another aspect of the present invention includes an observation system having an observation optical axis that overlaps with the illumination optical axis when viewed from the Y direction and is inclined with respect to the illumination optical axis when viewed from the X direction, and that acquires an observation image of the eye to be examined by photographing the eye onto which a light beam is projected by a light beam projection system, wherein a relative position detection unit detects the relative position of the eye to be examined in the X and Y directions with respect to the Scheimpflug optical system based on a Purkinje image included in the observation image photographed by the observation system, and detects the relative position of the eye to be examined in the Z direction with respect to the Scheimpflug optical system based on the Purkinje images included in the observation images photographed by the first and second photographing systems, and an alignment control unit performs alignment based on the detection results of the relative positions in the X, Y, and Z directions by the relative position detection unit. This enables more accurate alignment of the Scheimpflug optical system 12 with the eye to be examined.

[0016] In a microscope according to another aspect of the present invention, the light beam projection system projects a light beam of near-infrared light onto the subject's eye, thereby preventing the subject from feeling dazzled by the light beam.

[0017] In another aspect of the microscope of the present invention, the illumination system irradiates the anterior segment of the subject's eye with slit-shaped illumination light parallel to the object plane, and when alignment is performed by the alignment control unit, the microscope is equipped with a scanning control unit that drives a relative movement mechanism to move the Scheimpflug optical system in a direction perpendicular to the object plane, while continuously irradiating the subject's eye with illumination light by the illumination system and capturing images of the returning light by the image sensor, and a three-dimensional image generation unit that generates a three-dimensional image of the anterior segment of the eye based on the captured images of the returning light captured by the image sensor for each vertical position. [Effects of the Invention]

[0018] The present invention can align the Scheimpflug optical system with the eye to be examined with high precision. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 2 is a side view of the slit lamp microscope of the first embodiment as seen from the X direction side. [Figure 2] FIG. 2 is a top view of the slit lamp microscope of the first embodiment as viewed from the Y direction side. [Figure 3] FIG. 2 is an explanatory diagram for explaining the configurations and arrangement conditions of an illumination system and an imaging system. [Figure 4] FIG. 3 is an enlarged view of the XY spot projection system in FIG. 2. [Figure 5] 10A and 10B are explanatory diagrams for explaining photographing of the anterior segment by the observation system during alignment detection. [Figure 6] FIG. 2 is an explanatory diagram showing an example of an observation image of the anterior segment taken by the observation system. [Figure 7] FIG. 2 is a functional block diagram of a control device of the slit lamp microscope of the first embodiment. [Figure 8] 5 is a flowchart showing the flow of processing for generating a three-dimensional image of the anterior segment of the eye using the slit lamp microscope of the first embodiment. [Figure 9] 10 is an explanatory diagram for explaining photographing of the anterior eye segment by the photographing system during alignment detection in the second embodiment. FIG. [Figure 10] 1 is an explanatory diagram showing an example of a pair of observation images of the anterior segment captured by the imaging system. FIG. [Figure 11] 10A and 10B are explanatory diagrams for explaining alignment detection in the XYZ directions of the eye to be inspected relative to the Scheimpflug optical system, which is performed by an alignment detection unit according to the second embodiment. [Figure 12] 10 is a flowchart showing the flow of processing for generating a three-dimensional image of the anterior segment using a slit lamp microscope according to a second embodiment. [Figure 13] 10 is a flowchart showing the flow of a process for generating a three-dimensional image of the anterior segment of the eye to be examined by the slit lamp microscope of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] [First embodiment] Fig. 1 is a side view of a slit lamp microscope 10 of the first embodiment as viewed from the X direction. Fig. 2 is a top view of the slit lamp microscope 10 of the first embodiment as viewed from the Y direction. Of the mutually orthogonal X, Y, and Z directions in the figure, the Z direction is a front-to-back direction (also called the working distance direction) parallel to the front direction approaching the subject's eye E and the rear direction away from the subject, the X direction is a left-to-right direction based on the subject, and the Y direction is a direction perpendicular to both the X and Z directions (here, the up-down direction).

[0021] 1 and 2, a slit lamp microscope 10 corresponds to the microscope of the present invention and generates a three-dimensional image of the anterior segment Ea of the subject's eye E. The slit lamp microscope 10 mainly includes a Scheimpflug optical system 12, a moving mechanism 14, an observation system 50, an XY spot projection system 70, and a control device 100.

[0022] [Scheimpflug optical system] The Scheimpflug optical system 12 is held so as to be movable in the X direction by a moving mechanism 14 (described later), and performs cross-sectional imaging along the YZ plane of the anterior segment Ea of the subject's eye E. The Scheimpflug optical system 12 is composed of an illumination system 20 and imaging systems 30R and 30L. Note that the imaging systems 30R and 30L are omitted from FIG. 1 to avoid complication of the drawing.

[0023] <Lighting> The illumination system 20 has an illumination optical axis O1 parallel to the Z direction, and irradiates the anterior segment Ea of the subject's eye E with slit-shaped illumination light L (slit light LS) along this illumination optical axis O1. The illumination system 20 may have a configuration similar to that of an illumination system of a conventional slit lamp microscope, except that it is provided with an XY spot projection system 70 (described later), and includes, for example, an illumination light source 22, a slit forming unit 24, and an objective lens 26, which are arranged along the illumination optical axis O1.

[0024] The illumination light source 22 is, for example, an LED (light emitting diode), and emits illumination light L. Visible light is used as the illumination light L, but infrared light (near-infrared light) may also be used. The illumination light L emitted from the illumination light source 22 passes through a lens or the like (not shown) and then enters the slit forming portion 24.

[0025] The illumination light source 22 may be composed of multiple light sources. For example, the illumination light source 22 may include a light source that outputs continuous light and an illumination light source that outputs flash light. The illumination light source 22 may also include an illumination light source for the anterior segment and an illumination light source for the posterior segment. Furthermore, the illumination light source 22 may include multiple light sources that output illumination light L with different wavelengths.

[0026] The slit forming unit 24 has, for example, a pair of slit blades parallel to the Y direction, and by changing the distance between these slit blades in the X direction (slit width), changes the width of the area through which the illumination light L passes. As a result, the illumination light L that has passed through the slit forming unit 24 becomes slit light LS whose width direction is the X direction and whose length direction is the Y direction at the anterior segment position when focused.

[0027] The length of the slit light LS in the Y direction is set to be equal to or greater than the diameter of the cornea on the surface of the anterior eye segment Ea. The slit forming unit 24 may be configured to be able to change the length of the slit light LS in the Y direction.

[0028] The objective lens 26 irradiates the anterior segment Ea with the illumination light L that has passed through the slit forming portion 24. As a result, the anterior segment Ea is irradiated with the slit light LS.

[0029] The illumination system 20 may further include a focusing optical system (not shown) for changing the focus position of the slit light LS.

[0030] <Photography> The imaging systems 30R and 30L capture images of the anterior segment Ea illuminated by the slit light LS from two different directions. The imaging systems 30R and 30L may have the same configuration as the imaging systems of conventional slit lamp microscopes. For example, the imaging system 30R (corresponding to the first imaging system of the present invention) includes an optical system 32R and an image sensor 34R arranged along the imaging optical axis O2R. The imaging system 30L (corresponding to the second imaging system of the present invention) includes an optical system 32L and an image sensor 34L arranged along the imaging optical axis O2L.

[0031] The photographing optical axis O2R is parallel to the ZX plane and is inclined at an angle θR toward one side of the X direction with respect to the Z direction when viewed from the Y direction. The photographing optical axis O2L is parallel to the ZX plane and is inclined at an angle θL toward the other side of the X direction with respect to the Z direction when viewed from the Y direction. The angles θR and θL may be equal to or different from each other. The illumination optical axis O1, the photographing optical axis O2R, and the photographing optical axis O2L intersect at a single point.

[0032] Although not shown, the optical system 32R includes, for example, an objective lens, a variable magnification optical system, and an imaging lens, in that order from the side closest to the subject's eye E. Return light LA ​​from the anterior eye segment Ea passes through the objective lens and variable magnification optical system of the optical system 32R, and is imaged on the imaging surface 36R of the image sensor 34R by the imaging lens of the optical system 32R. The optical system 32R may further include a focusing optical system (not shown).

[0033] The return light LA ​​from the anterior segment Ea includes the return light of the slit light LS irradiating the anterior segment Ea, and may also include other light. Examples of the return light LA ​​include reflected light, scattered light, and fluorescent light. Examples of other light include light from the installation environment of the slit lamp microscope 10 (room light, sunlight, etc.). If an anterior segment illumination system (not shown) for illuminating the entire anterior segment Ea is provided separately from the illumination system 20, the return light (reflected light) of the anterior segment illumination light from this anterior segment illumination system may be included in the "other light."

[0034] The image sensor 34R is a CMOS (complementary metal oxide semiconductor) or CCD (charge coupled device) area sensor having a two-dimensional image sensing surface 36R. The image sensor 34R captures an image of the return light LA ​​formed on the image sensing surface 36R by the optical system 32R, and outputs an anterior eye segment cross-sectional image DR, which is an image of the return light LA, to the control device 100. The anterior eye segment cross-sectional image DR is an image of the YZ cross section at the slit light irradiation position of the anterior eye segment Ea.

[0035] The optical system 32L has the same configuration as the optical system 32R described above, and although not shown, includes an objective lens, a variable magnification optical system, an imaging lens, etc., and may further include a focusing optical system. As a result, the return light LA ​​from the anterior segment Ea irradiated with the slit light LS passes through the objective lens and variable magnification optical system of the optical system 32L and is imaged on the imaging surface 36L of the image sensor 34L by the imaging lens of the optical system 32L.

[0036] The image sensor 34L is a CMOS or CCD area sensor having a two-dimensional image pickup surface 36L, and captures the return light LA ​​formed on the image pickup surface 36L by the optical system 32L, and outputs an anterior-segment cross-sectional image DL, which is an image of the return light LA, to the control device 100. The anterior-segment cross-sectional image DL is an image of the YZ cross section at the slit light irradiation position of the anterior segment Ea.

[0037] <Scheimpflug camera> 3 is an explanatory diagram for explaining the configuration and arrangement conditions of the illumination system 20 and the imaging systems 30R and 30L. As shown in FIG. 3, the illumination system 20 and the imaging system 30L function as a Scheimpflug camera, and the illumination system 20 and the imaging system 30R also function as a Scheimpflug camera.

[0038] As shown by reference numeral 3A in Figure 3, the illumination system 20 and the imaging system 30L are configured so that an object plane SP (a plane on which the imaging planes 36R and 36L are focused) that includes the illumination optical axis O1 and is parallel to the YZ plane, a principal plane SL of the optical system 32L, and the imaging plane 36L satisfy the Scheimpflug condition (principle). More specifically, a plane H1 that includes the object plane SP, a plane H2L that includes the principal plane SL, and a plane H3L that includes the imaging plane 36L intersect on the same straight line. As a result, the imaging system 30L focuses on all positions within the object plane SP (for example, the range from the anterior surface of the cornea to the posterior surface of the lens of the anterior eye segment Ea) and captures the image, i.e., captures a cross-sectional image of the anterior eye segment Ea, thereby obtaining a cross-sectional image DL of the anterior eye segment.

[0039] Similarly, as shown by reference numeral 3B in Fig. 3, the illumination system 20 and the imaging system 30R are configured so that the object plane SP, the principal plane SR of the optical system 32R, and the imaging plane 36R satisfy the Scheimpflug condition. More specifically, the plane H1, the plane H2R including the principal plane SR, and the plane H3R including the imaging plane 36R intersect on the same straight line. As a result, the imaging system 30R also focuses on all positions within the object plane SP (the range from the anterior surface of the cornea to the posterior surface of the lens of the anterior eye segment Ea) and performs cross-sectional imaging of the anterior eye segment Ea, thereby obtaining a cross-sectional image DR of the anterior eye segment.

[0040] The configuration of the illumination system 20 and the imaging systems 30R, 30L that satisfies the Scheimpflug condition is realized by the configuration and arrangement of elements included in the illumination system 20, the configuration and arrangement of elements included in the imaging systems 30R, 30L, and the relative positions of the illumination system 20 and the imaging systems 30R, 30L. Parameters indicating the relative positions of the illumination system 20 and the imaging systems 30R, 30L include, for example, the above-mentioned angles θR, θL. The angles θR, θL are set to, for example, 17.5 degrees, 30 degrees, or 45 degrees. Note that the angles θR, θL may be variable.

[0041] [Movement mechanism] The moving mechanism 14 corresponds to the relative moving mechanism of the present invention, and although not shown, is composed of a stage on which the Scheimpflug optical system 12 is mounted, and an actuator such as a motor that moves this stage in the X, Y, and Z directions. Note that the configuration of the moving mechanism 14 is not particularly limited as long as it can move the Scheimpflug optical system 12 relative to the subject's eye E, and for example, the moving mechanism 14 may be one that moves a face support unit (not shown).

[0042] When aligning the Scheimpflug optical system 12 with the subject's eye E, the moving mechanism 14 performs alignment (auto-alignment) of the Scheimpflug optical system 12 with the subject's eye E by adjusting the position of the Scheimpflug optical system 12 in the XYZ directions under the control of the control device 100 described below.

[0043] Furthermore, when generating a 3D image of the anterior eye segment Ea, the moving mechanism 14, under the control of the control device 100 (described later), moves the Scheimpflug optical system 12 in a direction perpendicular to the illumination optical axis O1 in accordance with the illumination of the anterior eye segment Ea by the illumination system 20 with the slit light LS and the capture of the anterior eye segment cross-sectional images DR and DL by the imaging systems 30R and 30L. More specifically, the moving mechanism 14 moves the Scheimpflug optical system 12 in the X direction, which is a direction perpendicular to the object plane SP. This allows the anterior eye segment Ea to be scanned in the X direction with the slit light LS parallel to a YZ plane, with the X direction being the width direction and the Y direction being the length direction. In this embodiment, the range of movement of the Scheimpflug optical system 12 in the X direction by the moving mechanism 14, i.e., the scanning range of the slit light LS in the X direction relative to the anterior eye segment Ea, is set to a range that includes at least the cornea of ​​the anterior eye segment Ea. This allows the slit light LS to scan the entire cornea.

[0044] In this way, by scanning the anterior eye segment Ea in the X direction with the slit light LS from the illumination system 20 using the movement mechanism 14, the imaging systems 30R, 30L capture the returned light LA ​​(video image capture) and continuously output the anterior eye segment cross-sectional images DR, DL, thereby obtaining the anterior eye segment cross-sectional images DR, DL of the anterior eye segment Ea for each scanning position of the slit light LS in the X direction (see Patent Document 1 mentioned above). Note that the movement mechanism 14 used for alignment and the movement mechanism 14 that moves the Scheimpflug optical system 12 in the X direction may be separate entities.

[0045] [Observation system] Returning to FIG. 1, the observation system 50 is provided independently of the Scheimpflug optical system 12, and its position is fixed within the slit lamp microscope 10, that is, its position relative to the eye E to be examined is fixed.

[0046] The observation system 50 has an observation optical axis O3, and includes an optical system 52 and an image sensor 54 arranged along the observation optical axis O3 in this order from the side closest to the eye E to be examined.

[0047] The observation optical axis O3 overlaps with the illumination optical axis O1 when viewed from the Y direction, and is tilted downward in the Y direction (or upward in the Y direction) with respect to the illumination optical axis O1 when viewed from the X direction by an inclination angle θ. This inclination angle θ is set to an appropriate angle, for example, about 8 degrees, so that the slit light LS irradiated from the illumination system 20 onto the anterior eye segment Ea is not vignetted by the observation system 50. This prevents a decrease in the light intensity of the slit light LS irradiated from the illumination system 20 onto the anterior eye segment Ea.

[0048] The optical system 52 includes an imaging lens (not shown) and forms an image of the return light LB from the subject's eye E on the imaging element 54. The optical system 52 may include a focusing optical system.

[0049] The return light LB from the subject's eye E includes return light (anterior segment reflected light) of the anterior segment illumination light irradiated onto the anterior segment Ea from the aforementioned anterior segment illumination system (not shown), and return light from the anterior segment Ea of the subject's eye E onto which the XY spot light LP is projected by the XY spot projection system 70 described below.

[0050] The imaging element 54 is a CMOS or CCD area sensor that captures the returned light LB formed by the optical system 52 and outputs an observation image D of the subject's eye E (an anterior segment image obtained by photographing the anterior segment Ea) to the control device 100.

[0051] Although not shown, an eyepiece system that guides the return light LB to an eyepiece may be provided in the observation system 50, allowing the examiner to observe the observation image D through the eyepiece.

[0052] [XY spot projection system] 4 is an enlarged view of the XY spot projection system 70 in FIG. 2. As shown in FIG. 4 and the previously described FIGS. 1 and 2, the XY spot projection system 70 corresponds to the light beam projection system of the present invention and is used for alignment detection, which detects the relative position of the subject's eye E with respect to the Scheimpflug optical system 12, more specifically, for alignment detection in the X and Y directions. This XY spot projection system 70 has a projection optical axis O1A that is common to a part of the illumination optical axis O1, i.e., it is coaxial with the illumination system 20. The projection optical axis O1A branches off midway from the illumination optical axis O1, and the section from this branching position to the subject's eye E is common to the illumination optical axis O1.

[0053] The XY spot projection system 70 includes a spot light source 72, an optical system 74, and a mirror 76 arranged along a projection optical axis O1A.

[0054] An LED capable of emitting near-infrared light, for example, is used as the spot light source 72. During alignment detection, the spot light source 72 emits XY spot light LP (near-infrared light), which is spot light in the near-infrared wavelength range, as the light beam of the present invention under the control of a control device 100 described below.

[0055] The optical system 74 converts the XY spot light LP incident from the spot light source 72 into a parallel beam, and then emits the XY spot light LP toward a mirror 76. Although not shown, a diffuser plate, a diaphragm, and the like may be disposed between the spot light source 72 and the optical system 74.

[0056] The mirror 76 is, for example, a dichroic mirror, and is arranged at a position where the projection optical axis O1A branches off from the illumination optical axis O1. The mirror 76 reflects the XY spot light LP of near-infrared light incident from the spot light source 72 via the optical system 74 toward the subject's eye E, and transmits the visible illumination light L incident from the objective lens 26 and emits it toward the subject's eye E. In this way, the XY spot light LP is projected from the XY spot projection system 70 onto the anterior eye segment Ea. The beam diameter φ of the XY spot light LP will be described later.

[0057] Fig. 5 is an explanatory diagram for explaining the photographing of the anterior eye segment Ea (photographing of the return light LB) by the observation system 50 during alignment detection. Fig. 6 is an explanatory diagram showing an example of an observation image D (anterior eye segment image) of the anterior eye segment Ea photographed by the observation system 50.

[0058] As shown in Fig. 5, when an XY spot light LP is projected onto the anterior segment Ea from the XY spot projection system 70, the XY spot light LP is reflected by the corneal surface, the crystalline lens, and the like of the anterior segment Ea, thereby generating a Purkinje image PI. When the corneal radius of curvature of the subject's eye E is R, the Purkinje image PI is a virtual image observed at a position (R / 2) that is half the corneal radius of curvature R from the corneal apex of the subject's eye E. Note that the Purkinje image PI is a collective term for images generated by reflection from the front and rear surfaces of the cornea and the crystalline lens, and strictly speaking, they are called Purkinje first image, Purkinje second image, Purkinje third image, and Purkinje fourth image from the corneal surface side. The Purkinje image PI used in the first embodiment is the Purkinje first image generated by reflection from the corneal surface.

[0059] During alignment detection, the observation system 50 captures the returned light LB from the anterior segment Ea onto which the XY spot light LP is projected by the XY spot projection system 70, that is, photographs the anterior segment Ea. As a result, an observation image D of the anterior segment Ea including a Purkinje image PI as shown in FIG. 6 is captured by the observation system 50, and this observation image D is output from the observation system 50 to the control device 100.

[0060] The observation image D including the Purkinje image PI is a front image captured by the observation system 50 from a position substantially in front of the subject's eye E, so the Purkinje image PI will not be out of focus even if the alignment of the Scheimpflug optical system 12 with respect to the subject's eye E in the X and Y directions is significantly misaligned. Therefore, capturing an image of the anterior segment Ea with the observation system 50 can widen the detection range of the Purkinje image PI in the X and Y directions. Based on the position of the Purkinje image PI included in this observation image D, the control device 100 (described later) detects the relative position of the subject's eye E in the X and Y directions with respect to the Scheimpflug optical system 12, i.e., detects alignment in the X and Y directions (see JP 2015-85081 A).

[0061] The beam diameter φ (see FIG. 4) of the XY spot light LP projected onto the subject's eye E is adjusted to a size (e.g., 14 mm) that allows the control device 100 to detect the Purkinje image PI from within the observation image D. Note that a larger beam diameter φ of the Purkinje image PI allows the control device 100 to perform alignment detection even when the alignment of the Scheimpflug optical system 12 with respect to the subject's eye E is significantly deviated in the X and Y directions.

[0062] If the alignment of the Scheimpflug optical system 12 with respect to the subject's eye E in the Z direction is misaligned, the Purkinje image PI included in the observation image D will be out of focus (see JP 2015-85081 A). Therefore, the control device 100 can determine whether the Scheimpflug optical system 12 is properly aligned in the Z direction with respect to the subject's eye E, based on the degree of focus of the Purkinje image PI included in the observation image D. Note that the method for detecting the relative position of the subject's eye E with respect to the Scheimpflug optical system 12 in the Z direction, i.e., the method for detecting alignment in the Z direction, is not particularly limited, and a known method may be used, or a method described in a second embodiment described later may be used.

[0063] [Control device] FIG. 7 is a functional block diagram of the control device 100 of the slit lamp microscope 10 of the first embodiment. As shown in FIG. 7, the control device 100 includes an arithmetic circuit configured with various processors, memory, and the like. The various processors include a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), and a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA)). The various functions of the control device 100 may be implemented by a single processor, or by multiple processors of the same or different types.

[0064] In addition to the illumination system 20 (illumination light source 22), the photographing systems 30R, 30L (image sensors 34R, 34L), the moving mechanism 14, the observation system 50 (image sensor 54), and the XY spot projection system 70 (spot light source 72), the control device 100 is also connected to an operation unit 102 and a display unit 104.

[0065] The operation unit 102 is used for various operations of the slit lamp microscope 10, such as adjusting the position and orientation of the Scheimpflug optical system 12 (manual alignment operation), starting generation of a 3D image of the anterior segment Ea, and switching the observation mode of the slit lamp microscope 10. The operation unit 102 includes various operation devices provided on the slit lamp microscope 10, such as hardware keys (switches, buttons), an operation lever, a mouse, a keyboard, and an operation panel (including the display surface of the display unit 104).

[0066] A display device such as an LCD (Liquid Crystal Display) is used as the display unit 104. The display unit 104 displays the anterior eye segment cross-sectional images DR and DL captured by the imaging systems 30R and 30L, the observation image D of the anterior eye segment Ea captured by the observation system 50, and a three-dimensional image of the anterior eye segment Ea generated by a three-dimensional image generating unit 122 (described later).

[0067] The control device 100 functions as an illumination control unit 110, an imaging control unit 112, an alignment detection unit 114, an alignment control unit 116, a scanning control unit 118, an image acquisition unit 120, and a three-dimensional image generation unit 122 by reading and executing a control program stored in a memory unit (not shown).

[0068] The illumination control unit 110 controls the emission of illumination light L from the illumination light source 22, i.e., the irradiation of the slit light LS onto the anterior eye segment Ea by the illumination system 20. The illumination control unit 110 stops the emission of illumination light L from the illumination light source 22 when detecting the alignment of the subject's eye E with respect to the Scheimpflug optical system 12, and continues to emit illumination light L from the illumination light source 22 from the completion of alignment until the completion of scanning with the slit light LS.

[0069] The imaging control unit 112 controls the imaging of anterior-segment cross-sectional images DR and DL by the imaging systems 30R and 30L (imaging of the return light LA) and the imaging of the observation image D by the observation system 50 (imaging of the return light LB). When detecting alignment, the imaging control unit 112 causes the observation system 50 to capture the observation image D and stops the operation of the imaging systems 30R and 30L. Furthermore, from the completion of alignment until the completion of scanning with the slit light LS, the imaging control unit 112 causes at least the imaging systems 30R and 30L to continuously capture the anterior-segment cross-sectional images DR and DL (video imaging).

[0070] The alignment detection unit 114 corresponds to the relative position detection unit of the present invention and controls alignment detection of the subject's eye E in the X, Y, and Z directions with respect to the Scheimpflug optical system 12. For example, in response to an operation to start generating a three-dimensional image of the anterior eye segment Ea via the operation unit 102, the alignment detection unit 114 controls the illumination control unit 110 to stop irradiating the anterior eye segment Ea with the slit light LS from the illumination system 20. The alignment detection unit 114 also controls the XY spot projection system 70 to start projecting the XY spot light LP onto the subject's eye E, and controls the imaging control unit 112 to cause the observation system 50 to capture an image of the anterior eye segment Ea. As a result, an observation image D (see FIG. 6 ) of the anterior eye segment Ea including the Purkinje image PI is captured by the observation system 50, and this observation image D is output from the observation system 50 to the alignment detection unit 114.

[0071] Next, the alignment detection unit 114 detects the Purkinje image PI from the observation image D input from the observation system 50 by a known method, and performs alignment detection in the XY directions to detect the relative position of the eye E in the XY directions with respect to the Scheimpflug optical system 12 based on the position (XY position) of the Purkinje image PI in this observation image D. For example, if the detected coordinates of the Purkinje image PI in the observation image D, that is, the detected coordinates of the Purkinje image PI in the imaging plane of the image sensor 54 are (x, y), the position coordinates of the reference coordinates in this imaging plane are (x0, y0), and the magnification of the observation system 50 is β, then the position coordinates of the Purkinje image PI on the eye E are expressed by the following [Mathematical Expression 1].

[0072]

number

[0073] Then, the alignment detection unit 114 outputs the alignment detection results in the X and Y directions to the alignment control unit 116.

[0074] Furthermore, the alignment detection unit 114 detects the alignment of the eye E in the Z direction with respect to the Scheimpflug optical system 12 using a known method, and outputs the detection result to the alignment control unit 116 .

[0075] The alignment control unit 116 adjusts the position of the Scheimpflug optical system 12 in the XYZ directions by driving the moving mechanism 14 based on the alignment detection results in the XYZ directions input from the alignment detection unit 114, thereby aligning the Scheimpflug optical system 12 in the XYZ directions with respect to the subject's eye E. As a result, the position of the Scheimpflug optical system 12 is adjusted to the scanning start position of the slit light LS with respect to the anterior segment Ea.

[0076] The scan control unit 118 controls the scanning of the slit light LS on the anterior eye segment Ea in the X direction. When the above-mentioned alignment is completed, the scan control unit 118 stops the projection of the XY spot light LP onto the subject's eye E by the XY spot projection system 70, and controls the illumination control unit 110 and the imaging control unit 112 to start irradiating the anterior eye segment Ea with the slit light LS from the illumination system 20 and imaging of the anterior eye segment Ea by the imaging systems 30R and 30L.

[0077] The scan control unit 118 also drives the moving mechanism 14 to move the Scheimpflug optical system 12 in the X direction. As a result, the anterior eye segment Ea is scanned in the X direction by the slit light LS, and the imaging systems 30R and 30L capture cross-sectional images DR and DL of the anterior eye segment at each scanning position of the slit light LS in the X direction.

[0078] The image acquisition unit 120 acquires the anterior segment cross-sectional images DR, DL from the imaging systems 30R, 30L and outputs them to the three-dimensional image generation unit 122 every time the imaging systems 30R, 30L capture the anterior segment cross-sectional images DR, DL.

[0079] The three-dimensional image generating unit 122 generates a three-dimensional image of the anterior eye segment Ea based on the anterior eye segment cross-sectional images DR and DL for each of the above-mentioned scanning positions input from the image acquiring unit 120. The method for generating this three-dimensional image is a publicly known technique (see Patent Document 1 above), so a detailed description thereof will be omitted. In the first embodiment, the anterior eye segment Ea is imaged from two different directions by the imaging systems 30R and 30L. Therefore, even if an artifact is included in one of the anterior eye segment cross-sectional images DR and DL, as long as the other does not include an artifact, a three-dimensional image can be generated using the other. This enables the generation of a high-quality three-dimensional image.

[0080] [Operation of the first embodiment] FIG. 8 is a flowchart showing the flow of the process of generating a three-dimensional image of the anterior eye segment Ea by the slit lamp microscope 10 of the first embodiment configured as described above.

[0081] 8, after the subject's face is placed on a face support unit (not shown), the examiner operates the operation unit 102 to start generating a 3D image (step S1), and the alignment detection unit 114 controls the illumination control unit 110 to stop the irradiation of the slit light LS from the illumination light source 22 onto the anterior eye segment Ea, and controls the XY spot projection system 70 to start projecting the XY spot light LP onto the anterior eye segment Ea (step S2). By stopping the irradiation of the slit light LS of visible light onto the subject's eye E and projecting the XY spot light LP of near-infrared light onto the subject's eye E, the subject is prevented from feeling dazzled by the slit light LS and the XY spot light LP.

[0082] The alignment detection unit 114 also controls the imaging control unit 112 to capture an image of the returned light LB using the imaging element 54 of the observation system 50, i.e., to capture an image of the anterior eye segment Ea in which the Purkinje image PI is generated by the projection of the XY spot light LP (step S3). As a result, an observation image D of the anterior eye segment Ea including the Purkinje image PI is output from the observation system 50 to the alignment detection unit 114.

[0083] Next, the alignment detection unit 114 detects the alignment of the subject's eye E with respect to the Scheimpflug optical system 12 in the X and Y directions based on the position of the Purkinje image PI included in the observation image D input from the observation system 50, and outputs the detection result to the alignment control unit 116 (step S4). At this time, in the first embodiment, the anterior eye segment Ea is photographed by the observation system 50, so even if the alignment of the Scheimpflug optical system 12 with respect to the subject's eye E is significantly deviated in the X and Y directions, the Purkinje image PI in the observation image D is not blurred, making it possible to detect the alignment in the X and Y directions.

[0084] Furthermore, the alignment detection unit 114 detects the alignment of the eye E in the Z direction relative to the Scheimpflug optical system 12 using a known method, and outputs the detection result to the alignment control unit 116.

[0085] Then, the alignment detection unit 114 drives the moving mechanism 14 to align the Scheimpflug optical system 12 in the X, Y, and Z directions with respect to the subject's eye E (step S5), based on the alignment detection results in the X, Y, and Z directions input from the alignment detection unit 114. As a result, the position of the Scheimpflug optical system 12 is adjusted to the scanning start position of the slit light LS with respect to the anterior segment Ea.

[0086] When the alignment of the Scheimpflug optical system 12 is completed, the scan control unit 118 stops the projection of the XY spot light LP onto the anterior eye segment Ea by the XY spot projection system 70 and controls the illumination control unit 110 to start irradiating the anterior eye segment Ea with the slit light LS from the illumination system 20 (step S6). The scan control unit 118 also controls the photography control unit 112 to capture the returned light LA ​​using the image pickup elements 34R and 34L of the photography systems 30R and 30L, i.e., to photograph a cross section of the anterior eye segment Ea (step S7). As a result, the image pickup elements 34R and 34L output anterior eye segment cross-sectional images DR and DL to the image acquisition unit 120.

[0087] Then, the scan control unit 118 starts scanning the anterior eye segment Ea with the slit light LS by driving the moving mechanism 14 to move the Scheimpflug optical system 12 in the X direction (step S8). As a result, the imaging systems 30R, 30L capture anterior eye segment cross-sectional images DR, DL at each scanning position in the X direction of the slit light LS until the slit light LS reaches the scanning end position, and the image acquisition unit 120 acquires the anterior eye segment cross-sectional images DR, DL from the imaging systems 30R, 30L and outputs them to the three-dimensional image generation unit 122 (steps S9, S10: NO).

[0088] When the slit light LS reaches the scanning end position, scanning of the anterior eye segment Ea by the slit light LS ends (YES in step S10). Since scanning of the anterior eye segment Ea by the slit light LS starts after the above-mentioned alignment is performed, a desired range of the anterior eye segment Ea (e.g., the entire cornea) can be scanned by the slit light LS, and the imaging range of the cross section of the anterior eye segment Ea by the imaging systems 30R and 30L can be adjusted to a desired range (e.g., from the anterior surface of the cornea to the posterior surface of the lens).

[0089] When scanning of the anterior eye segment Ea with the slit light LS is completed, the three-dimensional image generating unit 122 generates a three-dimensional image of the anterior eye segment Ea based on the anterior eye segment cross-sectional images DR and DL for each scanning position input from the image acquiring unit 120 (step S11). The three-dimensional image of the anterior eye segment Ea is displayed on the display unit 104, or on various display devices connected to the control device 100 via a communication network (not shown). Furthermore, when a designation operation for designating a cross section of the three-dimensional image is performed by the operating unit 102, the control device 100 may generate a two-dimensional cross-sectional image showing the cross section of the three-dimensional image and display this two-dimensional cross-sectional image on the display unit 104 or the like (see Patent Document 1 mentioned above).

[0090] As described above, in the first embodiment, the XY spot light LP is projected onto the anterior eye segment Ea from the XY spot projection system 70 provided in the illumination system 20, and the anterior eye segment Ea is photographed by the observation system 50, thereby making it possible to detect the alignment of the subject's eye E with respect to the Scheimpflug optical system 12 based on the observation image D of the anterior eye segment Ea. This allows the Scheimpflug optical system 12 to be aligned with the subject's eye E with high precision.

[0091] [Second embodiment] Next, a slit lamp microscope 10 according to a second embodiment of the present invention will be described. In the slit lamp microscope 10 according to the first embodiment, the anterior eye segment Ea onto which the XY spot light LP is projected by the XY spot projection system 70 is imaged by the observation system 50, and alignment detection of the eye E to be examined with respect to the Scheimpflug optical system 12 is performed based on the observation image D captured by the observation system 50. In contrast, in the slit lamp microscope 10 according to the second embodiment, the anterior eye segment Ea onto which the XY spot light LP is projected is imaged by the imaging systems 30R and 30L, and the above-mentioned alignment detection is performed based on a pair of observation images DR1 and DL1 (see FIG. 10 ) of the anterior eye segment Ea captured by these imaging systems 30R and 30L.

[0092] The slit lamp microscope 10 of the second embodiment has basically the same configuration as the slit lamp microscope 10 of the first embodiment described above, and therefore, components that are identical in function or configuration to those of the first embodiment described above will be given the same reference numerals and their description will be omitted.

[0093] Fig. 9 is an explanatory diagram for explaining the photographing of the anterior eye segment Ea (photographing of the return light LA) by the photographing systems 30R and 30L during alignment detection in the second embodiment. Fig. 10 is an explanatory diagram showing an example of a pair of observation images DR1 and DL1 (anterior eye segment images) of the anterior eye segment Ea photographed by the photographing systems 30R and 30L.

[0094] As shown in Fig. 9, when the XY spot light LP is projected onto the anterior eye segment Ea by the XY spot projection system 70, the alignment detection unit 114 of the second embodiment controls the imaging control unit 112 to capture the returned light LA ​​using the image sensors 34R and 34L of the imaging systems 30R and 30L, i.e., to capture the anterior eye segment Ea using the imaging systems 30R and 30L. As a result, the anterior eye segment Ea including the Purkinje image PI is captured from different directions by the imaging systems 30R and 30L, i.e., stereoscopically captured. As a result, as shown in Fig. 10, a pair of observation images DR1 and DL1 including the observation image DR1 captured by the imaging system 30R and the observation image DL1 captured by the imaging system 30L are obtained, and this pair of observation images DR1 and DL1 are output from the imaging systems 30R and 30L to the alignment detection unit 114.

[0095] The pair of observation images DR1, DL1 are captured by the imaging systems 30R, 30L of the Scheimpflug optical system 12. The imaging systems 30R, 30L can capture images by focusing on all positions within the object plane SP. Therefore, even if the alignment of the Scheimpflug optical system 12 with respect to the eye E in the Z direction is significantly misaligned, the Purkinje image PI will not be out of focus. Therefore, in the second embodiment, the detection range of the Purkinje image PI in the Z direction can be widened. Note that in the second embodiment, if the alignment of the Scheimpflug optical system 12 with respect to the eye E in the X and Y directions is misaligned, the Purkinje image PI included in the observation image D will be out of focus.

[0096] 11 is an explanatory diagram for explaining alignment detection in the XYZ directions of the eye E to be examined relative to the Scheimpflug optical system 12, performed by the alignment detection unit 114 of the second embodiment. As shown in Fig. 12, in the second embodiment, stereoscopic photography of the anterior eye segment Ea is performed by the imaging systems 30R and 30L, and therefore the alignment detection unit 114 can perform alignment detection by analyzing a pair of observation images DR1 and DL1 using the principle of three-dimensional measurement by a general stereo camera.

[0097] Specifically, the alignment detection unit 114 detects the position (XY coordinates) of each Purkinje image PI from the pair of observation images DR1 and DL1. Here, the XY coordinates of the Purkinje image PI in the observation image DR1 are (xR, xL), and the XY coordinates of the Purkinje image PI in the observation image DL1 are (yR, yL). If the base length of the imaging systems 30R and 30L is B and the focal length of the imaging systems 30R and 30L is f, the alignment detection unit 114 calculates the position coordinates (X, Y, Z) of the Purkinje image PI (e.g., the corneal vertex) on the subject's eye E using the following [Equation 2]. In this way, the alignment detection unit 114 detects the relative position of the subject's eye E in the XYZ directions with respect to the Scheimpflug optical system 12, i.e., detects alignment in the XYZ directions.

[0098]

number

[0099] As in the first embodiment, the alignment control unit 116 of the second embodiment drives the moving mechanism 14 based on the alignment detection results in the X, Y, and Z directions input from the alignment detection unit 114 to align the Scheimpflug optical system 12 in the X, Y, and Z directions with respect to the subject's eye E.

[0100] FIG. 12 is a flowchart showing the flow of processing for generating a three-dimensional image of the anterior eye segment Ea by the slit lamp microscope 10 of the second embodiment.

[0101] 12, in the second embodiment, after the XY spot light LP is projected onto the subject's eye E by the XY spot projection system 70 (step S2), the alignment detection unit 114 controls the imaging control unit 112 to cause the imaging systems 30R and 30L to capture images of the anterior eye segment Ea in which the Purkinje image PI is generated by the projection of the XY spot light LP (step S3A). This allows the imaging systems 30R and 30L to be used as stereo cameras. Then, a pair of observation images DR1 and DL1 of the anterior eye segment Ea including the Purkinje image PI are output from the imaging systems 30R and 30L to the alignment detection unit 114.

[0102] Next, the alignment detection unit 114 detects the alignment of the eye E in the X, Y, and Z directions with respect to the Scheimpflug optical system 12 based on the positions of the Purkinje images PI included in the pair of observation images DR1, DL1 input from the imaging systems 30R, 30L, and outputs the detection result to the alignment control unit 116 (step S4A). At this time, in the second embodiment, the anterior eye segment Ea is imaged by the Scheimpflug optical system 12 (imaging systems 30R, 30L). Therefore, even if the alignment of the Scheimpflug optical system 12 with respect to the eye E is significantly deviated in the Z direction, the Purkinje images PI in the observation images DR1, DL1 are not blurred, and therefore alignment detection in the Z direction is possible.

[0103] The processing from step S5 onwards is the same as that in the first embodiment shown in FIG. 8, and therefore a detailed description thereof will be omitted here.

[0104] As described above, in the second embodiment, the anterior segment Ea onto which the XY spot light LP is projected from the XY spot projection system 70 is photographed by the imaging systems 30R and 30L, and it becomes possible to detect the alignment of the subject's eye E with respect to the Scheimpflug optical system 12 based on the pair of observation images DR1 and DL1 photographed by the imaging systems 30R and 30L. This makes it possible to align the Scheimpflug optical system 12 with the subject's eye E with high precision, similar to the first embodiment.

[0105] In addition, in the second embodiment, the anterior segment Ea is photographed using the Scheimpflug optical system 12, so there is no need to provide a separate camera to photograph the anterior segment Ea during alignment detection, and the configuration of the slit lamp microscope 10 can be simplified.

[0106] [Third embodiment] Next, a slit lamp microscope 10 according to a third embodiment of the present invention will be described. In the slit lamp microscope 10 according to the first embodiment, the anterior segment Ea onto which the XY spot light LP is projected is imaged by the observation system 50. Therefore, in the first embodiment, even if the alignment of the Scheimpflug optical system 12 with respect to the subject's eye E in the X and Y directions is significantly misaligned, the Purkinje image PI will not be blurred. Conversely, however, if the alignment of the Scheimpflug optical system 12 with respect to the subject's eye E in the Z direction is misaligned, the Purkinje image PI will be blurred. Therefore, the first embodiment is suitable for alignment in the X and Y directions.

[0107] On the other hand, in the slit lamp microscope 10 in the second embodiment, the anterior eye segment Ea onto which the XY spot light LP is projected is imaged by the imaging systems 30R and 30L of the Scheimpflug optical system 12. For this reason, in the second embodiment, even if the alignment of the Scheimpflug optical system 12 with respect to the eye E in the Z direction is significantly misaligned, the Purkinje image PI will not be out of focus. Conversely, however, if the alignment of the Scheimpflug optical system 12 with respect to the eye E in the X and Y directions is misaligned, the Purkinje image PI will be out of focus. Therefore, the second embodiment is suitable for alignment in the Z direction.

[0108] Therefore, in the slit lamp microscope 10 of the third embodiment, the observation system 50 is used to align the Scheimpflug optical system 12 with the eye E in the X and Y directions, and the imaging systems 30R and 30L are used to align the Scheimpflug optical system 12 with the eye E in the Z direction. Note that the slit lamp microscope 10 of the third embodiment has basically the same configuration as the slit lamp microscopes 10 of the above embodiments, and therefore, components that are the same in function or configuration as those of the above embodiments are given the same reference numerals and their description will be omitted.

[0109] FIG. 13 is a flowchart showing the flow of a process for generating a three-dimensional image of the anterior ocular segment Ea of the subject's eye E by the slit lamp microscope 10 of the third embodiment.

[0110] 13, in the third embodiment, after the XY spot light LP is projected onto the subject's eye E by the XY spot projection system 70 (step S2), the alignment detection unit 114 controls the imaging control unit 112 to cause the observation system 50 to capture an image of the anterior eye segment Ea in which a Purkinje image PI is generated by the projection of the XY spot light LP (step S3-1). As a result, an observation image D of the anterior eye segment Ea including the Purkinje image PI is output from the observation system 50 to the alignment detection unit 114.

[0111] Next, the alignment detection unit 114 detects the alignment of the eye E in the X and Y directions with respect to the Scheimpflug optical system 12 based on the observation image D, and outputs the detection result to the alignment control unit 116 (step S4-1). Then, based on the alignment detection result in the X and Y directions by the alignment detection unit 114, the alignment detection unit 114 drives the movement mechanism 14 to align the Scheimpflug optical system 12 in the X and Y directions with respect to the eye E (step S5-1).

[0112] When the alignment in the X and Y directions is completed, the alignment detection unit 114 controls the imaging control unit 112 to cause the imaging systems 30R and 30L to capture images of the anterior segment Ea in which the Purkinje image PI is generated (step S3-2). As a result, a pair of observation images DR1 and DL1 of the anterior segment Ea including the Purkinje image PI are output from the imaging systems 30R and 30L to the alignment detection unit 114.

[0113] Next, the alignment detection unit 114 detects the alignment of the eye E in the Z direction with respect to the Scheimpflug optical system 12 based on the pair of observation images DR1 and DL1, and outputs the detection result to the alignment control unit 116 (step S4-2). Then, based on the alignment detection result in the Z direction by the alignment detection unit 114, the alignment detection unit 114 drives the movement mechanism 14 to align the Scheimpflug optical system 12 in the Z direction with respect to the eye E (step S5-2). This completes the alignment of the Scheimpflug optical system 12 with respect to the eye E in the X, Y, and Z directions.

[0114] The processing from step S6 onwards is the same as that in the first embodiment shown in FIG. 8, and therefore a detailed description thereof will be omitted here.

[0115] As described above, in the third embodiment, by combining XY-direction alignment using the observation system 50 and Z-direction alignment using the imaging systems 30R and 30L, it is possible to align the Scheimpflug optical system 12 with the subject's eye E with higher precision than with each of the above-mentioned practical diameters.

[0116] [others] In each of the above embodiments, the slit light LS parallel to the YZ plane is scanned in the X direction by moving the Scheimpflug optical system 12 in the X direction using the moving mechanism 14, but the length direction and scanning direction of the slit light LS can be changed as desired. Furthermore, as described in Patent Document 1, the anterior segment Ea may be scanned with the slit light LS by rotating the Scheimpflug optical system 12 about the illumination optical axis O1.

[0117] In each of the above embodiments, the anterior segment Ea is irradiated with slit light LS, but the irradiation position of the slit light LS may be changed as appropriate within the subject's eye E. Furthermore, in each of the above embodiments, the subject's eye E is irradiated with slit light LS, but the subject's eye E may be irradiated with illumination light of various shapes other than slit light LS.

[0118] In the first embodiment, the Scheimpflug optical system 12 is provided with two imaging systems 30R and 30L, but the number of imaging systems may be one or three or more. In the second and third embodiments, the number of imaging systems may be three or more.

[0119] In the above embodiment, an XY spot light LP of near-infrared light is projected onto the test eye E from the XY spot projection system 70, but an XY spot light LP of visible light may also be projected onto the test eye E, and further, a light beam of any shape other than spot light may also be projected onto the test eye E.

[0120] In the above-described embodiments, an example has been described in which the control device 100 automatically drives the moving mechanism 14 to align the Scheimpflug optical system 12 with the subject's eye E. However, the present invention can also be applied to manual alignment. In manual alignment, the alignment state of the Scheimpflug optical system 12 with the subject's eye E is displayed on the display unit 104 based on the alignment detection results in the X, Y, and Z directions by the alignment detection unit 114, and the examiner manually operates the operation unit 102 in accordance with this display to drive the moving mechanism 14, thereby performing manual alignment in the X, Y, and Z directions. [Explanation of symbols]

[0121] 10. Slit Lamp Microscope 12 Scheimpflug optics 14 Moving mechanism 20 Lighting System 22 Light source 24 Slit forming section 26 Objective Lens 30L, 30R photography system 32L,32R optical system 34L, 34R image sensor 36L, 36R imaging surface 50 Observation System 52 Optical system 54 Image sensor 70 XY spot projection system 72 Spot Light 74 Optical system 76 Mirror 100 control device 102 Operation section 104 Display section 110 Lighting control unit 112 Imaging control unit 114 Alignment detection unit 116 Alignment control unit 118 Scanning control section 120 Image acquisition unit 122 3D image generation unit D Observation image DL,DR Anterior segment cross-sectional image Observation images of DL1 and DR1 E Eye to be examined Ea Anterior eye segment H1 Plane H2L, H2R Planes H3L, H3R Planes L Illumination light LA, LB Return light LP XY spot light LS Slit light O1 Illumination optical axis O1A Projection optical axis O2L, O2R Imaging optical axes O3 Observation optical axis PI Purkinje image R Corneal radius of curvature SL, SR Principal planes SP Object plane θ Tilt angle θL, θR Angles φ Beam diameter

Claims

1. an illumination system having an illumination optical axis and irradiating the subject's eye with illumination light along the illumination optical axis; an imaging system including an imaging element and an optical system that guides return light from the subject's eye illuminated with the illumination light to an imaging surface of the imaging element, and that images the return light using the imaging element; Equipped with In a microscope, an object plane including the illumination optical axis, a principal plane of the optical system, and the imaging plane satisfy the Scheimpflug condition, a relative movement mechanism that moves a Scheimpflug optical system including the illumination system and the imaging system relative to the eye to be examined; a light beam projection system provided in the illumination system and configured to project a light beam different from the illumination light onto the subject's eye along the illumination optical axis; an observation system that acquires an observation image of the eye to be examined, onto which the light beam is projected by the light beam projection system, by photographing the eye to be examined from a direction different from the direction of the illumination optical axis and the direction of the imaging optical axis of the imaging system; Equipped with When a direction parallel to the illumination optical axis is defined as a Z direction among X, Y, and Z directions which are orthogonal to each other, the imaging optical axis is perpendicular to a Y direction and is inclined with respect to the illumination optical axis when viewed from the Y direction, an observation optical axis of the observation system overlaps with the illumination optical axis when viewed from the Y direction and is inclined with respect to the illumination optical axis when viewed from the X direction; A microscope in which the tilt angle of the observation optical axis with respect to the illumination optical axis is set to an angle at which the illumination light is not eclipsed by the observation system.

2. An illumination system having an illumination optical axis and irradiating the subject's eye with illumination light along the illumination optical axis; an imaging system including an imaging element and an optical system that guides return light from the subject's eye illuminated with the illumination light to an imaging surface of the imaging element, and that images the return light using the imaging element; Equipped with In a microscope, an object plane including the illumination optical axis, a principal plane of the optical system, and the imaging plane satisfy the Scheimpflug condition, a relative movement mechanism that moves a Scheimpflug optical system including the illumination system and the imaging system relative to the eye to be examined; a light beam projection system provided in the illumination system and configured to project a light beam different from the illumination light onto the subject's eye along the illumination optical axis; an observation system that acquires an observation image of the eye to be examined, onto which the light beam is projected by the light beam projection system, by photographing the eye to be examined from a direction different from the direction of the illumination optical axis and the direction of the imaging optical axis of the imaging system; Equipped with A microscope in which the position of the observation system is fixed.

3. When a direction parallel to the illumination optical axis is defined as a Z direction among X, Y, and Z directions which are orthogonal to each other, the imaging optical axis is perpendicular to a Y direction and is inclined with respect to the illumination optical axis when viewed from the Y direction, 3. The microscope according to claim 2, wherein an observation optical axis of the observation system overlaps with the illumination optical axis when viewed from the Y direction and is tilted with respect to the illumination optical axis when viewed from the X direction.

4. 4. The microscope according to claim 3, wherein the tilt angle of the observation optical axis with respect to the illumination optical axis is set to an angle at which the illumination light is not eclipsed by the observation system.

5. 5. The microscope according to claim 1, wherein the light beam projection system projects the light beam of near-infrared light onto the subject's eye.

6. An illumination control unit that stops the illumination system from irradiating the illumination light onto the subject's eye while the light beam projection system projects the light beam onto the subject's eye; a relative position detection unit that detects a relative position of the eye to be examined with respect to the Scheimpflug optical system based on a Purkinje image included in the observation image acquired by the observation system; an alignment control unit that automatically drives the relative movement mechanism based on a detection result of the relative position by the relative position detection unit or drives the relative movement mechanism in response to a manual operation, thereby aligning the Scheimpflug optical system with the subject's eye; The microscope according to any one of claims 1 to 5, comprising:

7. the illumination system irradiates an anterior segment of the subject's eye with slit-shaped illumination light parallel to the object plane, a scanning control unit that, when the alignment control unit has performed the alignment, continuously performs irradiation of the subject's eye with the illumination light by the illumination system and imaging of the return light by the image sensor while driving the relative movement mechanism to move the Scheimpflug optical system in a direction perpendicular to the object plane; and a three-dimensional image generating unit that generates a three-dimensional image of the anterior eye segment based on the captured image of the return light captured by the image sensor for each position in the vertical direction; The microscope according to claim 6 , comprising:

8. An illumination system having an illumination optical axis and irradiating illumination light onto the subject's eye along the illumination optical axis; an imaging system including an imaging element and an optical system that guides return light from the subject's eye illuminated with the illumination light to an imaging surface of the imaging element, and that images the return light using the imaging element; Equipped with In a microscope, an object plane including the illumination optical axis, a principal plane of the optical system, and the imaging plane satisfy the Scheimpflug condition, a relative movement mechanism that moves a Scheimpflug optical system including the illumination system and the imaging system relative to the eye to be examined; a light beam projection system provided in the illumination system and configured to project a light beam different from the illumination light onto the subject's eye along the illumination optical axis; an illumination control unit that stops the illumination system from irradiating the subject's eye with the illumination light while the light beam projection system projects the light beam onto the subject's eye; an observation system that acquires an observation image of the eye to be examined, onto which the light beam is projected by the light beam projection system, by photographing the eye to be examined from a direction different from the direction of the illumination optical axis and the direction of the imaging optical axis of the imaging system; a relative position detection unit that detects a relative position of the eye to be examined with respect to the Scheimpflug optical system based on a Purkinje image included in the observation image acquired by the observation system; an alignment control unit that automatically drives the relative movement mechanism based on a detection result of the relative position by the relative position detection unit or drives the relative movement mechanism in response to a manual operation, thereby aligning the Scheimpflug optical system with the subject's eye; Equipped with the illumination system irradiates an anterior segment of the subject's eye with slit-shaped illumination light parallel to the object plane, a scanning control unit that, when the alignment control unit has performed the alignment, continuously performs irradiation of the subject's eye with the illumination light by the illumination system and imaging of the return light by the image sensor while driving the relative movement mechanism to move the Scheimpflug optical system in a direction perpendicular to the object plane; and a three-dimensional image generating unit that generates a three-dimensional image of the anterior eye segment based on the captured image of the return light captured by the image sensor for each position in the vertical direction; A microscope equipped with:

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