JP2023049320A - microscope - Google Patents

Abstract

To provide a microscope capable of fixing a visual axial direction of an eye to be examined while scanning the eye to be examined with illumination light.SOLUTION: A microscope equipped with a relative movement mechanism for relatively moving a Scheimpflug optical system including an illumination system and an imaging system with respective to an eye to be examined and scanning the eye to be examined with illumination light, in which an object surface including an illumination light axis, a principal surface of an optical system, and an imaging surface satisfy a Scheimpflug condition includes a fixation optical system in which a relative position with the eye to be examined is fixed, having a projection light axis defferent from the illumination light axis and an imaging light axis of the imaging system, and projecting fixation light onto the eye to be examined along the projection light axis. The fixation optical system projects the fixation light onto the eye to be examined at least while the relative movement of the Scheimpflug optical system is executed by the relative movement mechanism.SELECTED DRAWING: Figure 4

Description

The present invention relates to microscopes with Scheimpflug optics.

A slit lamp microscope described in Patent Document 1 includes a Scheimpflug optical system that functions as a Scheimpflug camera. A Scheimpflug optical system includes an illumination system and an imaging system including a lens system and an imaging device. The illumination system and the imaging system are composed of a plane including an object plane including the illumination optical axis of the illumination system (a plane on which an imaging plane described later is focused), a plane including the principal plane of the lens system, and an imaging plane of the imaging element. and the containing plane satisfy the Scheimpflug condition that they intersect on the same straight line. As a result, all positions in the object plane can be focused and photographed. Focus on and shoot.

In addition, in the slit lamp microscope described in Patent Document 1, the Scheimpflug optical system is moved in the direction perpendicular to the object plane (illumination optical axis), and the imaging system continuously performs cross-sectional imaging of the anterior segment of the eye. , while scanning the entire cornea of the anterior segment with slit light, an anterior segment cross-sectional image is obtained for each scanning position. Then, the slit lamp microscope generates a three-dimensional image of the anterior segment based on the anterior segment cross-sectional images for each scanning position.

JP 2019-213733 A

By the way, visible light is generally used in many cases as the slit light emitted from the illumination system of the slit lamp microscope to the anterior segment of the eye to be examined. For this reason, there is a possibility that the line of sight of the subject's eye may change due to the subject's eye following the slit light during scanning of the anterior segment of the eye with the slit light. In this case, since a good three-dimensional image of the anterior segment cannot be obtained, it is necessary to fix the visual line direction of the subject's eye during scanning with the slit light.

Here, for example, in an optical coherence tomography (OCT) device and a scanning laser ophthalmoscope (SLO), an eye to be examined is scanned with various types of measurement light, and return light from the eye to be examined is collected. A light emitting/receiving optical system for receiving light and a fixation optical system for fixing the eye to be examined are provided. In the OCT apparatus and SLO, the fixation is devised so that the subject does not follow the measurement light with his/her eyes.

However, in the OCT apparatus and the SLO, the projection/reception optical system and the fixation optical system use a common objective lens (optical system). Therefore, if the OCT apparatus and the fixation optical system of the SLO are applied to the slit lamp microscope described in Patent Document 1, the fixation optical system moves together with the Scheimpflug optical system when scanning the anterior segment of the eye with slit light. Therefore, fixation of the subject's eye cannot be performed.

The present invention has been made in view of such circumstances, and it is possible to fix the line-of-sight direction of the subject's eye while the Scheimpflug optical system is moved relative to the subject's eye, that is, while the subject's eye is scanned with the illumination light. The purpose is to provide a microscope that is

A microscope for achieving the object of the present invention has an illumination optical axis, an illumination system for illuminating an eye to be inspected with illumination light along the illumination optical axis, a first imaging device, and a subject irradiated with the illumination light. A Scheimpflug including an optical system for guiding return light from an eye examination to an imaging surface of a first imaging element, an imaging system for imaging the returned light with the first imaging element, and an illumination system and an imaging system for the eye to be examined. and a relative movement mechanism that relatively moves the optical system to scan the subject's eye with the illumination light, and the object plane including the illumination optical axis, the principal plane of the optical system, and the imaging plane meet the Scheimpflug conditions. in a microscope satisfying a fixation optical system for projecting fixation light onto the eye to be examined along the . project the

According to this microscope, while the eye to be inspected is scanned with the illumination light, the fixation light can be projected onto the eye to be inspected from the fixation optical system whose relative position to the eye to be inspected is fixed.

In the microscope according to another aspect of the present invention, the fixation optical system enables the subject to recognize the direction and amount of positional deviation of the subject's eye relative to a predetermined assumed placement position of the subject's eye. A fixation light is projected onto the subject's eye. This allows the subject to appropriately adjust the position of the subject's eye (face).

In a microscope according to another aspect of the present invention, the shape and luminous flux diameter of the fixation light projected onto the eye by the fixation optical system are adjusted to the entire fixation light when the positional deviation is within a predetermined range. is projected onto the subject's eye and the positional deviation exceeds a specified range, the shape and the luminous flux diameter are set such that the fixation light is vignetted according to the direction and amount of the positional deviation. As a result, the subject can recognize the direction and amount of positional deviation, so that the position of the subject's eye (face) can be appropriately adjusted.

In a microscope according to another aspect of the present invention, the fixation light has a cross shape. This allows the subject to recognize the displacement direction and displacement amount of the positional displacement.

In a microscope according to another aspect of the present invention, a fixation optical system projects fixation light onto the subject's eye via a pinhole. Thereby, the depth of field of the fixation optical system can be increased.

In a microscope according to another aspect of the present invention, an observation system whose relative position with respect to an eye to be examined is fixed, has an observation optical axis common to a part of the projection optical axis, and and an observation system that guides the return light from the eye to be inspected that is incident on the second imaging device or the eyepiece.

In the microscope according to another aspect of the present invention, when the Z direction is the direction parallel to the illumination optical axis among the mutually orthogonal XYZ directions, the photographing optical axis is perpendicular to the Y direction and viewed from the Y direction. The projection optical axis overlaps with the illumination optical axis when viewed in the Y direction and is inclined with respect to the illumination optical axis when viewed in the X direction.

In the microscope according to another aspect of the present invention, the illumination system irradiates the anterior segment of the subject's eye with slit-shaped illumination light parallel to the object plane, and the relative movement mechanism moves the Scheimpflug optical system to the object plane. move in a direction perpendicular to

The present invention can fix the line-of-sight direction of an eye to be inspected while scanning the eye to be inspected with illumination light.

It is the side view which looked at the slit lamp microscope from the X direction side. It is the top view which looked at the slit lamp microscope from the Y-direction side. FIG. 3 is an explanatory diagram for explaining respective configurations and arrangement conditions of an illumination system and an imaging system; 2 is an enlarged top view of the fixation optical system in FIG. 1 as viewed from above in the Y direction; FIG. FIG. 4 is an explanatory diagram showing an example of a fixation target presented to a subject when the displacement of the subject's eye is within a specified range; FIG. 4 is an explanatory diagram showing an example of a fixation target presented to a subject when the displacement of the subject's eye exceeds a specified range; FIG. 7 is an explanatory diagram showing an example of a fixation target presented to the subject when the displacement of the subject's eye is larger than in the example shown in FIG. 6; 4 is a flow chart showing the flow of processing for generating a three-dimensional image of the anterior segment using a slit lamp microscope. FIG. 10 is an explanatory diagram for explaining a modified example of the observation system of the slit lamp microscope;

[Overall Configuration of Slit Lamp Microscope]
FIG. 1 is a side view of the slit lamp microscope 10 viewed from the X-direction side. FIG. 2 is a top view of the slit lamp microscope 10 viewed from the Y-direction side. Of the XYZ directions orthogonal to each other in the figure, the Z direction is the front-back direction (also referred to as the working distance direction) parallel to the front direction approaching the eye E and the rear direction moving away from the subject, and the X direction is The horizontal direction is the horizontal direction with reference to the subject, and the Y direction is a direction perpendicular to both the XZ directions (here, the vertical direction).

As shown in FIGS. 1 and 2, the 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 eye E to be examined. The slit lamp microscope 10 roughly includes a Scheimpflug optical system 12 , a moving mechanism 14 , an observation system 50 , a fixation optical system 80 and a control device 100 .

[Scheimpflug optical system]
The Scheimpflug optical system 12 is held movably in the X direction by a moving mechanism 14, which will be described later, and performs cross-sectional imaging of the anterior segment Ea of the subject's eye E along the YZ plane. The Scheimpflug optical system 12 is composed of an illumination system 20 and photographing systems 30R and 30L. Note that the imaging systems 30R and 30L are not shown in FIG. 1 in order to avoid complication of the drawing.

<Lighting system>
The illumination system 20 has an illumination optical axis O1 parallel to the Z direction, and irradiates a slit-shaped illumination light L (slit light LS) to the anterior segment Ea of the eye to be examined E along this illumination optical axis O1. do. The illumination system 20 may have the same configuration as the illumination system of a conventional slit lamp microscope. include.

The illumination light source 22 uses, for example, an LED (light emitting diode) and emits illumination light L. As shown in FIG. Visible light is used as the illumination light L, but infrared light (near-infrared light) may be used. The illumination light L emitted from the illumination light source 22 enters the slit forming portion 24 after passing through a lens (not shown) or the like.

Note that the illumination light source 22 may be composed of a plurality of 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. Further, the illumination light source 22 may include an anterior segment illumination light source and a posterior segment illumination light source. Furthermore, the illumination light source 22 may include a plurality of light sources whose output wavelengths of the illumination light L are different from each other.

The slit forming part 24 has, for example, a pair of slit blades parallel to the Y direction, and the width of the region through which the illumination light L passes is changed by changing the interval (slit width) between these slit blades in the X direction. As a result, the illumination light L that has passed through the slit forming portion 24 becomes slit light LS having the width direction in the X direction and the length direction in the Y direction at the anterior segment position at the time of focusing.

The length of the slit light LS in the Y direction is set to be equal to or larger than the corneal diameter on the surface of the anterior segment Ea. Note that the slit forming section 24 may be configured to change the length of the slit light LS in the Y direction.

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

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

<Shooting system>
The imaging systems 30R and 30L image the anterior segment Ea irradiated with the slit light LS from two different directions. The imaging systems 30R and 30L may have the same configuration as the imaging system of a conventional slit lamp microscope. For example, the imaging system 30R includes an optical system 32R and an imaging element 34R arranged along the imaging optical axis O2R. The imaging system 30L also includes an optical system 32L and an imaging device 34L arranged along the imaging optical axis O2L.

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

Although illustration is omitted, the optical system 32R includes, for example, an objective lens, a variable magnification optical system, an imaging lens, and the like in order from the side closer to the eye E to be examined. The return light LA from the anterior segment Ea passes through the objective lens of the optical system 32R and the variable magnification optical system, and is imaged on the imaging surface 36R of the imaging element 34R by the imaging lens of the optical system 32R. Note that the optical system 32R may further include a focusing optical system (not shown).

The return light LA from the anterior segment Ea includes the return light of the slit light LS with which the anterior segment Ea is irradiated, and may further include other light. Examples of the returned light LA include reflected light, scattered light, fluorescence, and the like. Another example of light is light from the installation environment of the slit lamp microscope 10 (indoor light, sunlight, etc.). Further, when an anterior segment illumination system (not shown) for illuminating the entire anterior segment Ea is provided separately from the illumination system 20, the anterior segment illumination from this anterior segment illumination system Return light (reflected light) of light may be included in the “other light”.

The image pickup device 34R constitutes the first image pickup device of the present invention together with an image pickup device 34L, which will be described later. The imaging element 34R is a CMOS (complementary metal oxide semiconductor) or CCD (Charge Coupled Device) area sensor having a two-dimensional imaging surface 36R. The imaging element 34R captures the return light LA imaged on the imaging surface 36R by the optical system 32R, and outputs an anterior segment cross-sectional image DR, which is a captured image of the return light LA, to the control device 100. This anterior segment cross-sectional image DR is a YZ cross-sectional image of the anterior segment Ea at the slit light irradiation position.

The optical system 32L has the same configuration as the optical system 32R described above, and includes an objective lens, a variable magnification optical system, an imaging lens, etc., although not shown, 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 the variable magnification optical system of the optical system 32L, and the imaging element 34L is imaged by the imaging lens of the optical system 32L. An image is formed on the surface 36L.

The imaging element 34L is a CMOS or CCD area sensor having a two-dimensional imaging surface 36L, and captures an image of the return light LA formed on the imaging surface 36L by the optical system 32L. An anterior segment cross-sectional image DL, which is an image, is output to the control device 100 . This 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.

<Scheimpflug camera>
FIG. 3 is an explanatory diagram for explaining respective configurations 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.

As indicated by reference numeral 3A in FIG. 3, an object surface SP (a surface on which the imaging surfaces 36R and 36L are focused) that includes the illumination optical axis O1 and is parallel to the YZ plane, a main surface SL of the optical system 32L, and an imaging surface The illumination system 20 and the imaging system 30L are configured so that 36L and 36L satisfy the Scheimpflug condition (principle). More specifically, a plane H1 including the object surface SP, a plane H2L including the main surface SL, and a plane H3L including the imaging surface 36L intersect on the same straight line. As a result, the imaging system 30L focuses and photographs all positions within the object plane SP (for example, the range from the anterior surface of the cornea to the posterior surface of the crystalline lens of the anterior segment Ea). An eye cross-sectional image DL is obtained.

Similarly, as indicated by reference numeral 3B in FIG. 3, the illumination system 20 and the imaging system 30R are arranged such that the object surface SP, the main surface SR of the optical system 32R, and the imaging surface 36R satisfy the Scheimpflug condition. and are configured. More specifically, the plane H1, the plane H2R including the main surface SR, and the plane H3R including the imaging surface 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 of the anterior segment Ea to the posterior surface of the crystalline lens), and performs cross-sectional imaging of the anterior segment Ea. DR is obtained.

The configurations of the illumination system 20 and the imaging systems 30R and 30L that satisfy such Scheimpflug conditions include the configuration and arrangement of elements included in the illumination system 20, the configuration and arrangement of elements included in the imaging systems 30R and 30L, and illumination. This is realized by the relative positions of the system 20 and the imaging systems 30R and 30L. Parameters indicating the relative positions of the illumination system 20 and the imaging systems 30R and 30L include, for example, the angles θR and θL described above. The angles θR and θL are set to 17.5 degrees, 30 degrees, or 45 degrees, for example. Note that the angles θR and θL may be variable.

[Movement Mechanism]
The moving mechanism 14 corresponds to the relative moving mechanism of the present invention, and although not shown, includes a stage on which the Scheimpflug optical system 12 is mounted, an actuator such as a motor for moving the stage in the XYZ directions, It is composed of The structure of the moving mechanism 14 is not particularly limited as long as the Scheimpflug optical system 12 can be moved relative to the eye E to be examined. may

When aligning the Scheimpflug optical system 12 with respect to the eye E to be examined, the moving mechanism 14 adjusts the position of the Scheimpflug optical system 12 in the XYZ directions under the control of the control device 100, which will be described later. Alignment (auto-alignment) of the optical system 12 is executed.

Further, when the three-dimensional image of the anterior segment Ea is generated, the moving mechanism 14 irradiates the anterior segment Ea with the slit light LS by the illumination system 20 and performs The Scheimpflug optical system 12 is moved in the direction perpendicular to the illumination optical axis O1 in accordance with the photographing of the anterior segment cross-sectional images DR and DL. More specifically, the moving mechanism 14 moves the Scheimpflug optical system 12 in the X direction, which is the direction perpendicular to the object plane SP. As a result, the anterior segment Ea can be scanned in the X direction with the slit light LS parallel to the YZ plane having the X direction as the width direction and the Y direction as the length direction. At this time, in the present embodiment, the moving range of the Scheimpflug optical system 12 in the X direction by the moving mechanism 14, that is, the scanning range of the slit light LS for the anterior segment Ea in the X direction includes at least the cornea of the anterior segment Ea. is set to Therefore, the entire cornea can be scanned with the slit light LS.

In this way, while the slit light LS from the illumination system 20 is scanned in the X direction with respect to the anterior segment Ea by the moving mechanism 14, the photographing systems 30R and 30L capture images (moving images) of the return light LA and the cross-sectional images of the anterior segment. By continuously outputting DR and DL, anterior segment cross-sectional images DR and DL of the anterior segment Ea are obtained for each scanning position of the slit light LS in the X direction (see Patent Document 1 above). The moving mechanism 14 used for alignment and the moving mechanism 14 for moving the Scheimpflug optical system 12 in the X direction may be separate bodies.

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

The observation system 50 has an observation optical axis O3, and includes an optical system 52 and an imaging element 54 arranged along the observation optical axis O3 in order from the side closer to the eye E to be examined.

The observation optical axis O3 (also the projection optical axis O4, which will be described later) overlaps with the illumination optical axis O1 when viewed from the Y direction, and is positioned below the illumination optical axis O1 in the Y direction (Y direction) when viewed from the X direction. It is tilted by the tilt angle θ to the direction upward side is also possible). This tilt 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 to the anterior segment Ea is not eclipsed by the observation system 50 and a fixation optical system 80, which will be described later. there is This prevents a decrease in the light amount of the slit light LS irradiated from the illumination system 20 to the anterior segment Ea.

The optical system 52 includes an imaging lens (not shown) and the like, and forms an image of the return light LB (corresponding to the second return light) from the eye E to be examined on the imaging device 54 . Note that the optical system 52 may include a focusing optical system.

The return light LB from the subject's eye E includes the return light (anterior segment reflected light) of the anterior segment illumination light irradiated to the anterior segment Ea from the aforementioned anterior segment illumination system (not shown). is included.

The imaging element 54 is a CMOS or CCD area sensor and corresponds to the second imaging element of the present invention. The image pickup device 54 picks up the return light LB imaged by the optical system 52 and outputs an observation image D of the subject's eye E (an anterior segment image obtained by capturing the anterior segment Ea) to the control device 100 .

[Fixation optics]
FIG. 4 is an enlarged top view of the fixation optical system 80 in FIG. 1 as seen from above in the Y direction. Note that the Z1 direction in the drawing is a direction inclined by an inclination angle θ with respect to the Z direction, that is, a direction parallel to the observation optical axis O3. Also, the Y1 direction in the drawing is a direction perpendicular to both the Z1 direction and the X direction.

As shown in FIG. 4 and FIG. 1 described above, the fixation optical system 80 projects (irradiates) the fixation light LF onto the fundus Ef of the eye E to be examined. The fixation optical system 80 has a projection optical axis O4 in common with part of the observation optical axis O3 of the observation system 50, that is, is coaxial with the observation system 50. FIG. The projection optical axis O4 branches from the middle of the observation optical axis O3, and the area from this branch position to the subject's eye E is shared with the observation optical axis O3. Note that instead of branching the projection optical axis O4 from the middle of the observation optical axis O3, the observation optical axis O3 may be branched from the middle of the projection optical axis O4.

The fixation optical system 80 includes a fixation light source 81, a diffusion plate 82, a pinhole member 83, a lens 84, a cross reticle plate 85, a lens 86, and a mirror 87 arranged along the projection optical axis O4.

The fixation light source 81 uses, for example, a green LED, and emits green light, which is visible light, as fixation light LF. The fixation light LF emitted from the fixation light source 81 is diffused by the diffusion plate 82 and then passes through the pinhole 83 a formed in the pinhole member 83 . At this time, the depth of field of the fixation optical system 80 can be increased by reducing the diameter of the pinhole 83a. As a result, even if the fixation optical system 80 does not have a focusing mechanism, the fixation light LF can be focused within a certain diopter range.

The fixation light LF that has passed through the pinhole 83 a passes through the cross reticle plate 85 via the lens 84 . Thereby, a cross-shaped fixation light LF is projected onto the fundus oculi Ef. The fixation light LF transmitted through the cross reticle plate 85 is incident on the mirror 87 via the lens 86 .

The mirror 87 is, for example, a dichroic mirror or a half mirror, and is arranged at a branch position of the projection optical axis O4 from the observation optical axis O3. The mirror 87 reflects the fixation light LF incident from the lens 86 toward the eye E to be inspected, and conversely transmits the return light LB incident from the eye E to be inspected and emits it toward the optical system 52 .

Thus, the fixation optical system 80 projects the fixation light LF onto the fundus oculi Ef along the projection optical axis O4. At this time, the luminous flux diameter φ of the fixation light LF on the pupil of the eye E is adjusted to 4.5 mm, for example. As a result, a cross-shaped fixation light LF is formed on the fundus oculi Ef, as shown in the fundus image Df in the area surrounded by the dotted circle C in the drawing, in the fundus oculi Ef. A cross-shaped fixation target FP is presented. As a result, the visual line direction of the subject's eye E can be fixed in the direction of the fixation target FP, that is, the subject's eye E can be made to fixate.

Since the fixation optical system 80 is provided in the observation system 50 whose relative position to the subject's eye E is fixed, when the Scheimpflug optical system 12 is moved in the X direction by the moving mechanism 14, that is, the slit Even when the anterior segment Ea is scanned in the X direction by the light LS, the fixation of the subject's eye E can be stabilized (continued).

Further, in this embodiment, the fixation optical system 80 is used for rough alignment (also referred to as simple alignment), which is positional adjustment of the subject's eye E (face) with respect to the slit lamp microscope 10 performed by the subject. For example, when the slit lamp microscope 10 is of the screenoscope type, the examinee needs to look into an eyepiece viewing hole (not shown) provided in the slit lamp microscope 10 . At this time, when the subject's eye E is displaced in the direction (XY direction) perpendicular to the illumination optical axis O1 from the assumed arrangement position assumed in the slit lamp microscope 10 (hereinafter simply referred to as "positional displacement"). There is

In such a case, if the positional deviation of the eye to be examined E is within a predetermined specified range (also referred to as an allowable range) from the assumed arrangement position, for example, the observation range of the observation system 50, the eye to be examined with respect to the Scheimpflug optical system 12 Detection of the relative position of E (alignment detection) and alignment of the Scheimpflug optical system 12 with respect to the eye E can be performed. However, if the positional deviation of the subject's eye E exceeds the above-described specified range, alignment detection and alignment cannot be performed.

Therefore, in the present embodiment, the subject can recognize the displacement direction and displacement amount of the subject's eye E with respect to the assumed placement position based on the fixation target FP presented to the subject's eye E by the fixation optical system 80. At the same time, the subject can also recognize whether or not this positional deviation is within the above specified range. Therefore, when the displacement of the eye E to be examined with respect to the assumed arrangement position is within the specified range, the entire fixation light LF is projected onto the fundus oculi Ef. The shape of the fixation light LF and the luminous flux diameter φ on the pupil are set so that the fixation light LF projected onto the fundus oculi Ef is vignetted according to the shift direction and amount of shift.

Specifically, in this embodiment, the shape of the fixation light LF projected onto the fundus oculi Ef is set to a cross shape as described above, and the fixation light LF is vignetted when the positional deviation exceeds the specified range. (the size of the fixation target FP presented to the subject) on the pupil is set as follows.

FIG. 5 is an explanatory diagram showing an example of the fixation target FP presented to the subject when the displacement of the subject's eye E is within a specified range. FIG. 6 is an explanatory diagram showing an example of the fixation target FP presented to the subject when the displacement of the subject's eye E exceeds the prescribed range. FIG. 7 is an explanatory diagram showing an example of the fixation target FP presented to the subject when the displacement of the subject's eye E is greater than in the example shown in FIG. 6 and 7 show an example of vignetting of the fixation target FP. The vignetting state of the fixation target FP depends on the diopter of the eye E to be examined, the pupil diameter, and the alignment position in the Z direction. different.

As shown in FIG. 5, when the displacement of the subject's eye E is within a specified range, the subject can visually recognize the entire cross-shaped fixation target FP. In this case, the subject can easily recognize that position adjustment (rough alignment) of the subject's eye E (face) is unnecessary.

On the other hand, as shown in FIGS. 6 and 7, when the displacement of the eye E to be examined exceeds the specified range, the subject may partially visually recognizes the vignetting fixation target FP. In this case, the subject can recognize that the above-described rough alignment is necessary, and can recognize the direction in which the fixation target FP is vignetting among the up, down, left, and right directions. The direction in which the subject's eye E (face) is moved can be determined based on the direction. As a result, the subject can roughly adjust the position of the subject's eye E (face) so that a part of the cross-shaped fixation target FP is not vignetted, that is, so that the lengths in the vertical and horizontal directions are uniform. Alignment can be performed. As a result, since the positional deviation of the eye to be examined E is kept within the prescribed range, even if the pupil diameter of the eye to be examined E is large, the eye to be examined E can be placed within the alignment detection range or the observation range. Observation of E, etc. become possible.

[Control device]
The control device 100 includes an arithmetic circuit composed of various processors, memories, etc., and controls each part of the slit lamp microscope 10 based on an operation instruction from an examiner input to an operation unit (not shown). Overall control of operations. The control device 100 performs projection of the fixation light LF onto the eye E to be examined by the fixation optical system 80, alignment detection and alignment of the Scheimpflug optical system 12 with respect to the eye E to be examined, and projection of the fixation light LF onto the anterior segment Ea by the illumination system 20. irradiating the slit light LS, photographing the anterior segment cross-sectional images DR and DL by the imaging systems 30R and 30L, scanning the anterior segment Ea with the slit light LS, and generating a three-dimensional image of the anterior segment Ea. Control.

The control device 100 controls the fixation light source 81 in a state before the start of alignment of the Scheimpflug optical system 12 with respect to the eye E to be examined, such as when the power of the slit lamp microscope 10 is turned on. Projection of the fixation light LF onto the fundus oculi Ef by the optical system 80 is executed. Further, while the anterior segment Ea is being scanned by the slit light LS, the control device 100 controls the fixation light source 81 to prevent the fixation optical system 80 from projecting the fixation light LF onto the fundus oculi Ef. let it run.

Further, when an instruction to generate a three-dimensional image of the anterior segment Ea is received by an operation unit (not shown), the control device 100 controls the observation system 50 (or the imaging systems 30R and 30L) to An observation image D of Ea is captured, and based on this observation image D, alignment detection is performed to detect the relative position of the subject's eye E with respect to the Scheimpflug optical system 12 . Then, based on the result of the alignment detection, the control device 100 drives the moving mechanism 14 to adjust the XYZ direction position of the Scheimpflug optical system 12, thereby performing XYZ direction alignment of the Scheimpflug optical system 12 with respect to the eye E to be examined. (precision alignment). Since the alignment detection and alignment are well-known techniques, detailed descriptions thereof are omitted here.

Further, when the alignment described above is completed, the control device 100 irradiates the anterior segment Ea with the slit light LS by the illumination system 20, photographs the cross section of the anterior segment Ea by the imaging systems 30R and 30L, and moves the moving mechanism 14. and scanning of the slit light LS in the X direction (see Patent Document 1 above). Then, based on the anterior segment cross-sectional images DR and DL captured by the imaging systems 30R and 30L at each scanning position during the scanning of the slit light LS, the control device 100 performs a three-dimensional image of the anterior segment Ea by a known method. An image is generated (see Patent Document 1 above).

[Action of slit lamp microscope]
FIG. 8 is a flow chart showing the flow of processing for generating a three-dimensional image of the anterior segment Ea by the slit lamp microscope 10 configured as described above. Here, a screenoscope type slit lamp microscope 10 will be described as an example.

As shown in FIG. 8, when the slit lamp microscope 10 is powered on, the control device 100 controls the fixation light source 81 to start emission of the fixation light LF from the fixation light source 81 . Then, when the subject looks into the eyepiece peephole (not shown) of the slit lamp microscope 10, the fixation optical system 80 projects the fixation light LF onto the fundus oculi Ef, giving the subject a cruciform shape. A fixation target FP is presented (step S1). As a result, the subject recognizes whether rough alignment, which is position adjustment of the subject's eye E (face), is unnecessary or necessary based on whether or not the entire cross-shaped fixation target FP is visible.

When part of the fixation target FP is vignetted according to the direction and amount of positional deviation of the eye E to be examined, the examinee determines that the fixation target FP is vignetted in each of the up, down, left, and right directions. The direction in which the subject's eye E (face) is to be moved is discriminated based on the direction in which it is present. Then, the subject performs rough alignment for adjusting the position of the subject's eye E so that the lengths of the fixation target FP in the vertical and horizontal directions are uniform (step S2). As a result, the positional deviation of the eye to be inspected E is kept within the specified range, so that alignment detection, observation of the eye to be inspected E, and the like are possible.

Next, when the examiner operates an operation unit (not shown) to start generating a three-dimensional image of the anterior segment Ea, the control device 100 causes the observation system 50 to photograph the anterior segment Ea. Alignment detection of the subject's eye E with respect to the Scheimpflug optical system 12 is performed based on the observed image D (anterior segment image) obtained in . Then, the control device 100 drives the moving mechanism 14 to align the Scheimpflug optical system 12 based on the alignment detection result (step S3). Thereby, the Scheimpflug optical system 12 is position-adjusted to the scanning start position of the slit light LS with respect to the anterior segment Ea.

When the alignment is completed, the control device 100 starts irradiation of the slit light LS from the illumination system 20 to the anterior segment Ea (step S4), and the return light LA by the imaging elements 34R and 34L of the imaging systems 30R and 30L. Imaging, that is, cross-sectional imaging of the anterior segment Ea is performed (step S5). As a result, the anterior segment cross-sectional images DR and DL are output from the imaging elements 34R and 34L to the control device 100 .

Then, the control device 100 drives the moving mechanism 14 to move the Scheimpflug optical system 12 in the X direction, thereby starting scanning of the anterior segment Ea with the slit light LS (step S6). As a result, while the slit light LS is being scanned in the X direction, the anterior segment cross-sectional images DR and DL are captured by the imaging systems 30R and 30L at each scanning position in the X direction of the slit light LS. acquire anterior segment cross-sectional images DR and DL from the imaging systems 30R and 30L (step S7).

In addition, the control device 100 causes the fixation optical system 80 to project the fixation light LF onto the fundus oculi Ef in synchronization with the start of scanning of the anterior segment Ea by the slit light LS (step S8). As a result, the fixation target FP is presented to the subject's eye E, so that the gaze direction of the subject's eye E can be fixed in the direction of the subject's eye E, that is, the subject's eye E can be made to fixate. As a result, it is possible to prevent the subject from following the slit light LS with his/her eyes when scanning the anterior segment Ea with the slit light LS.

Thereafter, the processes from step S6 to step S8 are repeatedly executed until the slit light LS reaches the scanning end position (NO in step S9). Then, when the scanning of the anterior segment Ea by the slit light LS is completed (YES in step S9), the control device 100 scans the anterior segment cross-sectional images DR, Based on DL, a three-dimensional image of the anterior segment Ea is generated (step S10).

As described above, in this embodiment, by providing the fixation optical system 80 in the observation system 50 whose relative position to the eye E to be examined is fixed, while the Scheimpflug optical system 12 is moving in the X direction, that is, While the anterior segment Ea is being scanned by the slit light LS, the visual fixation of the subject's eye E can be performed by the fixation optical system 80 to fix the line-of-sight direction of the subject's eye. As a result, a good three-dimensional image of the anterior segment Ea is obtained.

[Modified example of observation system]
FIG. 9 is an explanatory diagram for explaining a modification of the observation system 50 of the slit lamp microscope 10. As shown in FIG. In the above embodiment, the observation system 50 guides the return light LB to the image sensor 54, but the return light LB is led to the eyepiece 59. ) may be observable. In this case, an eyepiece system 56 is provided in the observation system 50 as shown in FIG. The eyepiece system 56 includes a beam splitter 57 , an imaging lens 58 and an eyepiece 59 .

The beam splitter 57 is arranged on the observation optical axis O3, transmits part of the return light LB from the eye E to be emitted to the optical system 52, and reflects the rest toward the imaging lens 58. . The imaging lens 58 guides the return light LB incident from the beam splitter 57 to the eyepiece lens 59 . Thereby, the examiner can observe the observation image D through the eyepiece lens 59 .

[others]
In the above embodiment, the Scheimpflug optical system 12 is moved in the X direction by the moving mechanism 14 to scan the slit light LS parallel to the YZ plane in the X direction. The direction can be changed arbitrarily. Further, as described in Patent Document 1, the Scheimpflug optical system 12 may be rotated about the illumination optical axis O1 to scan the anterior segment Ea with the slit light LS.

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

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

In the above embodiment, the fixation optical system 80 projects the cross-shaped fixation light LF onto the fundus oculi Ef. The shape of the fixation light LF is not particularly limited as long as is recognizable. may

10 Slit Lamp Microscope 12 Scheimpflug Optical System 14 Moving Mechanism 20 Illumination System 22 Illumination Light Source 24 Slit Forming Unit 26 Objective Lenses 30L, 30R Imaging Systems 32L, 32R Optical Systems 34L, 34R Imaging Elements 36L, 36R Imaging Surface 50 Observation System 52 Optics System 54 Imaging device 56 Eyepiece system 57 Beam splitter 58 Imaging lens 59 Eyepiece 80 Fixation optical system 81 Fixation light source 82 Diffusion plate 83 Pinhole member 83a Pinhole 84 Lens 85 Cross reticle plate 86 Lens 87 Mirror 100 Control device C Dotted circle D Observation images DL, DR Cross-sectional image of anterior segment Df Fundus image E Eye to be examined Ea Anterior segment Ef Fundus FP Fixation target H1 Plane H2L, H2R Plane H3L, H3R Plane L Illumination light LA, LB Return light LF Fixation Sighting light LS Slit light O1 Illumination optical axis O2L, O2R Imaging optical axis O3 Observation optical axis O4 Projection optical axis SL, SR Main surface SP Object surface θ Tilt angle θL Angle θR Angle φ Luminous flux diameter

Claims (8)

an illumination system having an illumination optical axis and irradiating an eye to be inspected with illumination light along the illumination optical axis;
and an optical system that guides the return light from the eye to be examined irradiated with the illumination light to an imaging surface of the first image pickup device, and the return light is picked up by the first image pickup device. shooting system and
a relative movement mechanism that relatively moves a Scheimpflug optical system including the illumination system and the imaging system with respect to the eye to be inspected to scan the eye to be inspected with the illumination light;
with
In a microscope in which an object plane including the illumination optical axis, a principal plane of the optical system, and the imaging plane satisfy Scheimpflug conditions,
A fixation optical system having a fixed relative position to the eye to be inspected, and having a projection optical axis different from the illumination optical axis and the imaging optical axis of the imaging system, along the projection optical axis comprising a fixation optical system that projects fixation light onto the eye to be examined;
A microscope in which the fixation optical system projects the fixation light onto the subject's eye at least while the relative movement of the Scheimpflug optical system is being performed by the relative movement mechanism. The fixation optical system emits the fixation light to the eye to be examined, with which the subject can recognize the direction and amount of positional displacement of the eye to be examined with respect to a predetermined assumed position of the eye to be examined. 2. A microscope as claimed in claim 1, which projects onto the . When the positional deviation is within a predetermined range, the fixation optical system projects the shape and luminous flux diameter of the fixation light onto the eye to be inspected so that the entire fixation light is projected onto the eye to be inspected. and when the positional deviation exceeds the specified range, the fixation light is set to a shape and a luminous flux diameter in which the fixation light is vignetted according to the direction and amount of the positional deviation. microscope. 4. A microscope according to claim 2, wherein said fixation light has a cross shape. The microscope according to any one of claims 1 to 4, wherein the fixation optical system projects the fixation light onto the subject's eye via a pinhole. An observation system whose relative position with respect to the eye to be examined is fixed, and which has an observation optical axis common to a part of the projection optical axis, and is incident from the eye to be examined along the observation optical axis 6. The microscope according to any one of claims 1 to 5, further comprising an observation system that guides the returned light to the second imaging device or an eyepiece. When the Z direction is the direction parallel to the illumination optical axis among the mutually orthogonal XYZ directions, the imaging optical axis is perpendicular to the Y direction and is aligned with the illumination optical axis when viewed from the Y direction. is slanted with respect to
7. The projection optical axis according to any one of claims 1 to 6, wherein the projection optical axis 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. Microscope as described. The illumination system irradiates the anterior ocular segment of the eye to be inspected with slit-shaped illumination light parallel to the object plane,
8. A microscope according to claim 1, wherein said relative movement mechanism moves said Scheimpflug optical system in a direction perpendicular to said object plane.

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