JP7271953B2 - Corneal endothelial cell imaging device and corneal endothelial cell imaging program - Google Patents

Description

The present disclosure relates to a corneal endothelial cell imaging device and a corneal endothelial cell imaging program for capturing a corneal endothelial cell image of an eye to be examined.

BACKGROUND ART A corneal endothelial cell imaging apparatus that captures an endothelial cell image by irradiating the cornea of an eye to be inspected with illumination light and receiving corneal reflected light from endothelial cells of the cornea is known (see Patent Document 1). For example, in such a corneal endothelial cell imaging device, an alignment bright spot is formed between the optical axis of the device and the center of curvature of the anterior surface of the cornea based on light reflected from the anterior surface of the cornea, and an alignment bright spot image is obtained. An endothelial cell image of the cornea is captured by aligning the eye to be examined and the device using the device.

JP 2015-107352 A

By the way, when using an alignment bright spot image based on the anterior surface of the cornea, as in the above-described corneal endothelial cell imaging apparatus, the center of curvature of the anterior surface of the cornea and the center of curvature of the posterior surface of the cornea in the direction in which the eye to be examined faces the apparatus. If the positions of , are misaligned, good endothelial cell images may not be captured. For example, when the presenting position of the fixation target fixed by the eye to be inspected is changed and the eye to be inspected is rotated, a good endothelial cell image may not be captured.

In view of the conventional technology described above, the technical problem of the present disclosure is to provide a corneal endothelial cell imaging apparatus capable of satisfactorily capturing a corneal endothelial cell image of an eye to be examined.

In order to solve the above problems, the present disclosure is characterized by having the following configurations.

(1) A corneal endothelial cell imaging apparatus according to a first aspect of the present disclosure projects illumination light emitted from a first light source toward the cornea of an eye to be examined, and the corneal reflected light of the illumination light is detected by the first detector. An imaging optical system for capturing an endothelial cell image of the cornea and an alignment index for the XY directions emitted from the second light source are projected toward the cornea, and the corneal reflected light of the alignment index is projected onto the cornea. and an alignment optical system for detecting with a second detector via an objective lens arranged in the front direction of the subject's eye , the corneal endothelial cell imaging apparatus comprising: based on a detection signal from the second detector and detecting at least the second alignment luminescent spot of a first alignment luminescent spot based on corneal reflected light from the anterior surface of the cornea and a second alignment luminescent spot based on corneal reflected light from the posterior surface of the cornea. setting means; and alignment control means for adjusting the relative position between the subject eye and the imaging optical system based on the second alignment luminescent spot so that the second alignment luminescent spot coincides with the optical axis of the objective lens. and.
(2) A corneal endothelial cell imaging program according to a second aspect of the present disclosure projects illumination light emitted from a first light source toward the cornea of an eye to be examined, and corneal reflected light of the illumination light is detected by a first detector. An imaging optical system for capturing an endothelial cell image of the cornea and an alignment index for the XY directions emitted from the second light source are projected toward the cornea, and the corneal reflected light of the alignment index is projected onto the cornea. and an alignment optical system for detection by a second detector via an objective lens arranged in the front direction of the subject's eye , and a corneal endothelial cell image capturing program for use in a corneal endothelial cell imaging apparatus, wherein the corneal endothelium A first alignment bright spot based on corneal reflected light from the anterior surface of the cornea and a corneal reflection from the posterior surface of the cornea, based on the detection signal from the second detector, are executed by the processor of the cell imaging device. a second alignment luminescent spot based on reflected light; a setting step of detecting at least the second alignment luminescent spot; and an alignment control step of adjusting the relative position between the eye to be inspected and the imaging optical system based on the alignment bright spots.

1 is an external view of a corneal endothelial cell imaging device; FIG. It is a figure which shows the optical system and control system of a corneal-endothelial cell imaging device. FIG. 2 is a diagram of a target projection optical system provided in the corneal endothelial cell imaging apparatus as viewed from the subject. FIG. 4 is a diagram schematically showing positions where alignment luminescent spot images are formed in an eye to be inspected, an anterior segment image captured by an anterior segment observation optical system, and an endothelial cell image captured by a corneal imaging optical system; 4 is a flow chart showing a control operation; It is an example of an anterior segment image displayed on a monitor. It is a figure explaining alignment control. FIG. 4 is a diagram showing epithelial peaks detected by a detector; It is an example of a detection area set based on the first alignment luminescent spot image. It is an example of an anterior segment image displayed on a monitor.

An example, which is one of typical embodiments of the present disclosure, will be described with reference to the drawings.

FIG. 1 is an external view of a corneal endothelial cell imaging device 100 (hereinafter abbreviated as imaging device 100). Hereinafter, the X direction shown in FIG. 1 will be referred to as the left-right direction of the imaging device 100 , the Y direction as the up-down direction of the imaging device 100 , and the Z direction as the front-back direction of the imaging device 100 .

The photographing device 100 is a device for photographing an image of the corneal region of the eye E to be examined. The photographing device 100 has a photographing section 1 , a base 2 , a face support unit 3 , a moving table 4 , a drive section 5 , an operation section 6 and a monitor 7 . The imaging unit 1 is provided on the driving unit 5 and accommodates each optical system in the imaging device 100 . The face support unit 3 is fixed to the base 2 and supports the subject's face. A movable table 4 is provided on the base 2 and moves in the X and Z directions. The driving unit 5 is provided on the moving table 4 and moves in the Y direction.

The operation unit 6 (joystick 6) is operated by the examiner. The joystick 6 is provided with a movement mechanism for moving the photographing unit 1 relative to the eye E to be examined in the X, Y and Z directions. For example, in this embodiment, as a moving mechanism, a sliding mechanism (not shown) for sliding the moving table 4 on the base 2 in the X direction and the Z direction is provided. When the examiner tilts and operates the joystick 6, the movable table 4 slides on the base 2 in the XZ direction. Further, for example, in this embodiment, as a moving mechanism, a sliding mechanism (not shown) for sliding the drive unit 5 with respect to the moving table 4 in the Y direction is provided. When the examiner rotates a rotary knob 6a provided on the joystick 6, the driving section 5 slides in the Y direction with respect to the moving table 4, and the photographing section 1 moves in the Y direction accordingly.

As a configuration for moving the photographing unit 1 with respect to the subject's eye E, a configuration in which the movement is performed by driving the motor in the driving unit 5 without providing a mechanical sliding mechanism may be employed. Further, the manual operation unit such as the joystick 6 may be configured to have a touch panel.

The monitor 7 is provided on the surface of the imaging unit 1 opposite to the subject side (that is, the examiner side). However, the monitor 7 may be arranged on another surface of the photographing unit 1, at a position different from the photographing unit 1 (for example, the moving table 4, etc.), or may be provided separately from the photographing device 100. .

The optical system and control system of the imaging device 100 will be described with reference to FIGS. 2 and 3. FIG. FIG. 2 is a diagram showing the optical system and control system of the imaging device 100. As shown in FIG. Note that FIG. 2 shows an optical arrangement of the optical system housed in the photographing unit 1 when viewed from above. FIG. 3 is a view of a target projection optical system 40 (described later) of the optical system included in the imaging apparatus 100 as seen from the subject side.

First, the schematic configuration of the optical system of the imaging device 100 will be described. The imaging device 100 has a corneal imaging optical system 10 , an alignment optical system 30 , a working distance detection optical system 50 and a fixation optical system 60 .

<Corneal imaging optical system>
The corneal imaging optical system 10 projects illumination light emitted from a light source onto the cornea of the subject's eye, and detects the corneal reflected light of the illumination light with a detector to capture an endothelial cell image of the cornea.

The corneal imaging optical system 10 has an illumination optical system 10a and a light receiving optical system 10b. The corneal imaging optical system 10 projects light from an illumination light source 11 (“first light source” in this embodiment) toward the cornea Ec of the subject's eye E by means of an illumination optical system 10a. In addition, the corneal imaging optical system 10 receives light emitted from the illumination light source 11 and reflected by the cornea Ec by the light-receiving optical system 10b. receive light. By using the corneal imaging optical system 10, the imaging apparatus 100 can photograph the corneal region of the subject's eye in a non-contact manner.

The optical axes of the illumination optical system 10a and the light receiving optical system 10b intersect on the eye E to be examined. Advantageously, the illumination optical system 10a and the light receiving optical system 10b are arranged symmetrically with respect to a central axis. For example, in this embodiment, the optical axis L2 of the illumination optical system 10a and the optical axis L3 of the light receiving optical system 10b are arranged symmetrically with respect to the central axis L1 (optical axis L1 described later).

The illumination optical system 10a projects illumination light from the illumination light source 11 toward the cornea Ec. The illumination optical system 10 a of this embodiment has an illumination light source 11 , a condenser lens 12 , a slit plate 13 , a dichroic mirror 14 and a projection lens 15 . The illumination light source 11 emits illumination light used for photographing the corneal region of the eye E to be inspected. In this embodiment, the illumination light source 11 emits visible light. For example, a visible LED, a flash lamp, or the like may be used as the illumination light source 11 . The dichroic mirror 14 reflects visible light and transmits infrared light. The slit plate 13 and the cornea Ec are arranged at substantially conjugate positions with respect to the projection lens 15 . Light emitted from the illumination light source 11 is condensed by the condensing lens 12 and passes through a slit formed in the slit plate 13 . The slit light passing through the slit plate 13 is reflected by the dichroic mirror 14, converged by the projection lens 15, and irradiated onto the cornea Ec.

The light-receiving optical system 10b receives corneal reflected light from the cornea Ec containing endothelial cells with the imaging device 22 . The light receiving optical system 10b of this embodiment includes an objective lens 16, a dichroic mirror 17, a mask 18, a first imaging lens 19, a mirror 20, a second imaging lens 21, and a two-dimensional imaging device 22 (hereinafter referred to as imaging device 22). omitted). The dichroic mirror 17 reflects visible light and transmits infrared light. The mask 18 is arranged at a position substantially conjugate with the cornea Ec. The first imaging lens 19 and the second imaging lens 21 form an imaging optical system that forms an endothelial cell image on the imaging device 22 . The imaging device 22 is used to capture endothelial cell images. The imaging element 22 is arranged at a position substantially conjugate with the cornea Ec. As the imaging device 22, for example, a two-dimensional CCD image sensor (Charge coupled device image sensor), a two-dimensional CMOS image sensor (Complementary Metal Oxide Semiconductor Image Sensor), or the like may be used.

The light guided to the cornea Ec along the optical axis L1 of the illumination optical system 10a is reflected by the cornea Ec and guided in the direction of the optical axis L3 (oblique direction) of the light receiving optical system 10b. After that, the light passes through an objective lens 16 and a dichroic mirror 17 and is once imaged on a mask 18 . The mask 18 blocks light that becomes noise when acquiring an endothelial cell image. The light passing through the mask 18 is imaged on the imaging element 22 via the first imaging lens 19 , the mirror 20 and the second imaging lens 21 . As a result, a high-magnification endothelial cell image is obtained.

<Alignment optical system>
The alignment optical system 30 projects the XY-direction alignment index emitted from the light source onto the cornea of the subject's eye, and detects the corneal reflected light of the alignment index with a detector.

The alignment optical system 30 has a target projection optical system 40, a front projection optical system 30a, and an anterior segment observation optical system 30b (alignment detection optical system 30b). The alignment optical system 30 projects light from the infrared light sources 41a, 41b, and 43a to 43d toward the cornea Ec of the eye E to be inspected by the index projection optical system 40. FIG. Further, the alignment optical system 30 projects light from the infrared light source 31 (“second light source” in this embodiment) toward the cornea Ec of the subject's eye E using the front projection optical system 30a. Further, the alignment optical system 30 uses the anterior segment observation optical system 30b to irradiate the corneal reflected light emitted from the infrared light source and reflected by the cornea Ec to the imaging device 35 (“second detector” in this embodiment). to receive light.

The index projection optical system 40 projects an alignment index for the XYZ directions obliquely toward the periphery of the cornea Ec (in other words, the periphery of the corneal vertex position). By using the alignment index projected from the index projection optical system 40, rough alignment of the photographing unit 1 with respect to the subject's eye is performed. For example, when the eye to be examined E is greatly deviated from the imaging surface of the imaging element 22, the alignment index projected from the index projection optical system 40 is projected by the imaging unit 1 (in other words, the corneal imaging optical system) with respect to the eye to be examined E. It is used to know the direction to move the system 10). The target projection optical system 40 has a first projection optical system 40a and a second projection optical system 40b (see FIG. 3).

FIG. 3 is a diagram of the first projection optical system 40a and the second projection optical system 40b as viewed from the subject side. The first projection optical system 40a is inclined at a predetermined angle with respect to the optical axis L1. The first projection optical system 40a projects an alignment index at infinity from an oblique direction toward the cornea Ec. In this embodiment, the first projection optical system 40a has infrared light sources 41a and 41b and collimator lenses 42a and 42b, respectively, and is arranged symmetrically with respect to the optical axis L1. project an alignment index at infinity. The infrared light source 41a and the infrared light source 41b in the first projection optical system 40a are arranged on substantially the same meridian as the horizontal direction passing through the optical axis L1 (see FIG. 3).

The lights emitted from the infrared light sources 41a and 41b are collimated by collimator lenses 42a and 42b, respectively, and projected onto the cornea Ec. As a result, an alignment index image n1a based on the corneal reflected light of the alignment index projected by the infrared light source 41a and an alignment index image n1a based on the corneal reflected light of the alignment index projected by the infrared light source 41b are formed on the cornea Ec. An index image n1b is formed (see FIG. 6).

The second projection optical system 40b is inclined at a predetermined angle with respect to the optical axis L1. The second projection optical system 40b projects an alignment index at a finite distance from an oblique direction toward the cornea Ec. In this embodiment, the second projection optical system 40b has infrared light sources 43a to 43d, is arranged symmetrically with respect to the optical axis L1, and projects an alignment index at a finite distance to the subject's eye E ( See Figure 3). The infrared light sources 43a and 43b are arranged above the optical axis L1 and are arranged at the same height in the Y direction. Also, the infrared light sources 43c and 43d are arranged below the optical axis L1 and are arranged at the same height in the Y direction. Also, the infrared light sources 43a and 43b, and the infrared light sources 43c and 43d are arranged vertically symmetrically with respect to the optical axis L1.

The light from the infrared light sources 43a and 43b is irradiated obliquely upward toward the upper portion of the cornea Ec. As a result, an alignment index image n2a, which is a virtual image of the alignment index projected by the infrared light source 43a, and an alignment index image n2b, which is a virtual image of the alignment index projected by the infrared light source 43b, are formed on the cornea Ec. formed (see FIG. 6). The light from the infrared light sources 43c and 43d is irradiated obliquely downward toward the lower portion of the cornea Ec. As a result, an alignment index image n2c, which is a virtual image of the alignment index projected by the infrared light source 43c, and an alignment index image n2d, which is a virtual image of the alignment index projected by the infrared light source 43d, are formed on the cornea Ec. formed (see FIG. 6).

Note that, with such an index projection optical system 40, the alignment index images n1a and n1b produced by the first projection optical system 40a are positioned at the same horizontal position as the alignment luminescent spot image i1 produced by the front projection optical system 30a. , are formed symmetrically. Further, the alignment index images n2a and n2b by the second projection optical system 40b are formed symmetrically with respect to the alignment luminescent spot image i1 above the alignment luminescent spot image i1 by the front projection optical system 30a. Alignment index images n2c and n2d by the second projection optical system 40b are formed symmetrically with respect to the alignment luminescent spot image i1 below the alignment luminescent spot image i1 by the front projection optical system 30a.

The front projection optical system 30a projects an alignment index for the XY directions from the front toward the center of the cornea Ec (that is, the corneal vertex position or approximately the corneal vertex position). By using the alignment index projected from the front projection optical system 30a, fine alignment with respect to the subject's eye E is performed. For example, when the photographing unit 1 is roughly aligned with the subject's eye E based on the alignment index projected from the index projection optical system 40, the image of the alignment index projected from the front projection optical system 30a (that is, An alignment luminescent spot image i1), which will be described later, is formed on the eye E to be examined. For example, the alignment index projected from the front projection optical system 30a is used to substantially match the center of the cornea Ec of the eye E to be examined and the optical axis L1. In this embodiment, an alignment reference position ( later) is set.

The front projection optical system 30 a has an infrared light source 31 , a projection lens 32 and a half mirror 33 . When the infrared light source 31 is turned on, the front projection optical system 30a projects the alignment index onto the cornea Ec from the direction of the optical axis L1. The alignment index emitted from the infrared light source 31 is reflected by the half mirror 33 through the projection lens 32 and projected onto the cornea Ec. As a result, an alignment bright spot image i1 based on the corneal reflected light of the alignment index projected by the infrared light source 31 is formed on the cornea Ec at the corneal vertex of the subject's eye E (see FIG. 4). As the alignment luminescent point image i1, a first alignment luminescent point image i1a based on the corneal front surface reflected light from which the alignment index is reflected from the anterior surface of the cornea Ec, and a corneal image from which the alignment index is reflected from the posterior surface of the cornea Ec. A second alignment bright spot image i1b based on the rear surface reflected light is formed, which will be described later.

The anterior segment observation optical system 30b receives corneal reflected light of the alignment index from the cornea Ec by the imaging device 35 . The anterior segment observation optical system 30b has an objective lens 34 and a two-dimensional image sensor 35 (hereinafter abbreviated as image sensor 35). The imaging device 35 is used to capture an alignment bright spot image i1. The imaging device 35 is arranged at a position substantially conjugate with the cornea Ec of the eye E to be examined. For example, as the imaging device 35, a two-dimensional CCD image sensor, a two-dimensional CMOS image sensor, or the like may be used.

The light guided to the cornea Ec along the optical axis L1 of the front projection optical system 30a is reflected by the cornea Ec and guided to the anterior segment observation optical system 30b. After that, the light passes through the half mirror 33 and forms an image on the imaging device 22 via the objective lens 34 . As a result, an alignment bright spot image i1 is acquired.

In this embodiment, the anterior segment observation optical system 30b is also used as an optical system for observing and photographing the subject's eye E from the front direction. That is, the imaging device 35 captures an alignment bright spot image i1 together with an anterior segment image of the anterior segment of the eye E to be inspected. When capturing an anterior segment image of the subject's eye E, an anterior segment illumination light source (not shown) is used. Of course, the alignment optical system 30 includes an optical system for detecting the corneal reflected light of the alignment index projected onto the eye E by the index projection optical system 40 and the front projection optical system 30a, and an optical system for observing and photographing the eye E. and an optical system for the above may be separately provided.

In this embodiment, the alignment optical system 30 has been described with an example of a configuration including the target projection optical system 40 and the front projection optical system 30a, but the present invention is not limited to this. The alignment optical system 30 may be configured to include at least the front projection optical system 30a. That is, it is sufficient that the alignment optical system 30 captures the alignment bright spot image i1 based on the corneal reflected light of the alignment index for the XY directions projected toward the center of the cornea Ec of the eye E to be inspected.

<Working distance detection optical system>
The working distance detection optical system 50 projects light (that is, detection light) for detecting the focus state of the corneal imaging optical system 10 toward the cornea Ec. By using the detection light projected from the working distance detection optical system 50, precise alignment in the Z direction of the photographing unit 1 with respect to the eye to be examined is performed. The working distance detection optical system 50 has a projection optical system 50a and a detection optical system 50b.

The optical axis L2 of the light projecting optical system 50a and the optical axis L3 of the detecting optical system 50b are arranged at symmetrical positions with respect to the optical axis L1. The light projecting optical system 50a projects detection light for detecting the focus state of the corneal imaging optical system 10 with respect to the cornea Ec of the subject's eye E from an oblique direction toward the cornea Ec. On the other hand, the detection optical system 50b includes a detector 54 (photodetector 54) in which a plurality of pixels are arranged, and detects corneal reflected light from the cornea Ec of the detection light projected from the light projecting optical system 50a. detected by device 54 .

The projection optical system 50 a has an illumination light source 51 , a condenser lens 52 , a pinhole plate 53 and a projection lens 15 . The pinhole plate 53 is arranged at a position substantially conjugate with the cornea Ec. The detection optical system 50 b has an objective lens 16 and a detector 54 . For example, a one-dimensional light receiving element (line sensor) may be used as the detector 54 . The detector 54 and the cornea Ec are arranged at substantially conjugate positions.

The detection light emitted from the illumination light source 51 illuminates the pinhole plate 53 through the condenser lens 52 . The detection light that has passed through the aperture of the pinhole plate 53 is projected onto the cornea Ec via the projection lens 15 and reflected by the cornea Ec in the direction of the optical axis L3. The corneal reflected light is then detected by detector 54 via objective lens 16 and dichroic mirror 17 . The detector 54 outputs the intensity distribution of the corneal reflected light in the depth direction as a signal to the controller 70 . The output signal from detector 54 is used to detect the alignment state in the Z direction. Here, the light receiving position of the detection light on the detector 54 changes according to the positional relationship between the photographing unit 1 and the subject's eye E in the Z direction. The photographing apparatus 100 detects the amount of misalignment in the Z direction by detecting the misalignment between the light receiving position of the detection light and the proper alignment position.

<Fixation optics>
The fixation optical system 60 has a fixation target for fixating the subject's eye, and changes the line-of-sight direction of the subject's eye by switching the presentation position of the fixation target. In this embodiment, a fixation lamp is used as a fixation target, and the line-of-sight direction of the subject's eye is changed by switching the lighting position of the fixation lamp. For example, a plurality of fixation lights are arranged on a plane perpendicular to the optical axis. The fixation optical system 60 has an internal fixation optical system 60a (see FIG. 2) and an external fixation optical system 60b (see FIG. 3).

The internal fixation optical system 60 a projects a fixation lamp onto the subject's eye E from inside the imaging unit 1 . The internal fixation optical system 60a has visible light sources 61a to 61i (fixation lights 61a to 61i), a projection lens 62, and a dichroic mirror 63. The visible light sources 61a to 61i are arranged at different positions with respect to the direction orthogonal to the optical axis L4, and are used to guide the line of sight of the subject's eye. The visible light source 61a is arranged near the optical axis L4. The visible light source 61a is used to guide the line of sight of the eye E to be examined in the front direction. The visible light source 61a is turned on when obtaining an endothelial cell image of the central portion of the cornea Ec. Also, the visible light sources 61b to 61i are arranged on the same circumference around the optical axis L4. In the example shown in FIG. 2, they are arranged at intervals of 45 degrees at 0, 45, 90, 135, 180, 225, 270, and 315 degrees when viewed from the subject. there is The visible light sources 61b to 61i are used to guide the line of sight of the subject's eye E in the peripheral direction. Visible light sources 61b-61i are turned on when obtaining endothelial cell images around the center of the cornea Ec. The dichroic mirror 63 reflects visible light and transmits infrared light. Visible light emitted from the visible light sources 61a to 61i is collimated by the projection lens 62, reflected by the dichroic mirror 63, and guided to the eye E to be examined. As a result, the fixation lamp is projected onto the fundus of the eye E to be examined.

The external fixation optical system 60b projects a fixation lamp onto the subject's eye E from outside the photographing unit 1 . The external fixation optical system 60b may be provided outside the imaging unit 1 and on the surface facing the subject. The external fixation optical system 60b has visible light sources 64a-64f (fixation lights 64a-64f). The visible light sources 64a to 64f are arranged at different positions in the XY directions and used to guide the line of sight of the subject's eye. When the eye E is fixed to the visible light sources 64a to 64f of the external fixation optical system 60b, the eye E is fixed to the visible light sources 64a to 64f of the internal fixation optical system 60a. The direction of the line of sight can be greatly swung. Also, the visible light sources 64a to 64f are arranged on the same circumference around the optical axis L1. In the example shown in FIG. 3, they are arranged at intervals of 60 degrees at 2 o'clock, 4 o'clock, 6 o'clock, 8 o'clock, 10 o'clock, and 12 o'clock when viewed from the subject. The visible light sources 64a to 64f are used to guide the line of sight of the subject's eye E in the peripheral direction. Visible light sources 64a-64f are turned on to obtain peripheral endothelial cell images in the cornea Ec. In this case, the endothelial cell images acquired using the visible light sources 64a to 64f are images further outside than the endothelial cell images acquired using the visible light sources 61b to 61g.

For example, when capturing an endothelial cell image of the lower cornea, the lighting position of the fixation lamp is set upward, and the line of sight of the subject's eye E is guided upward. Also, when capturing an endothelial cell image of the upper cornea, the lighting position of the fixation lamp is set downward, and the line of sight of the subject's eye E is guided downward.

In this embodiment, a fixation optical system that changes the direction of guiding the line of sight of the subject's eye E by switching and turning on a plurality of fixation lamps with different positions is taken as an example, but this is not necessarily the case. not. For example, as a fixation optical system that has a configuration in which a single fixation lamp can be moved in a direction orthogonal to the optical axis, and changes the direction of guiding the line of sight of the subject's eye E by moving the fixation lamp. good too. Further, for example, it has a display panel such as a liquid crystal display, an organic EL (Electro Luminescence) display, a plasma display, or the like, and controls the light emission position of the display panel to change the direction in which the line of sight of the subject's eye E is guided. It may be a viewing optical system.

Next, a schematic configuration of the control system of the imaging device 100 will be described. The imaging device 100 has a control section 70 , an HDD 74 , an image processing IC 75 and an operation input section 76 .

Each part of the photographing apparatus 100 is controlled by the control part 70 . The control unit 70 is connected to the drive unit 5 , joystick 6 , various light sources, various imaging elements, HDD 74 , image processing IC 75 , operation input unit 76 and monitor 7 . Note that the monitor 7 may be a touch panel. In this case, the monitor 7 also serves as part of the operation input section 76 .

The control unit 70 includes a CPU 71 , a ROM 72 and a RAM 73 . The CPU 71 is a processing device for executing various types of processing related to the imaging device 100 . The ROM 72 is a non-volatile storage device storing various control programs and fixed data. The RAM 73 is used as a rewritable volatile storage device, but is of course not limited to this. Temporary data is stored in the RAM 73 when the control program is executed.

The HDD 74 is used as a rewritable non-volatile storage device, but is of course not limited to this. In this embodiment, the HDD 74 stores an anterior segment image of the subject's eye.

The image processing IC 75 is used as an image forming section. The image processing IC 75 forms an endothelial cell image of the subject's eye E by processing the signal output from the imaging device 22 . Further, by processing the signal output from the imaging element 35, an anterior segment image of the eye E to be examined is formed. In this embodiment, the image processing IC 75, which is a circuit separate from the control unit 70, performs image processing such as forming an image of the subject's eye. The configuration may be such that a part or all of it is performed by the control unit 70 .

Alignment operations in the XY directions between the subject's eye E and the photographing unit 1 by the photographing apparatus 100 will now be described. In the photographing apparatus 100, when the adjustment of the relative position between the subject's eye E and the imaging unit 1 (corneal imaging optical system 10) using the index projection optical system 40 and the front projection optical system 30a is completed, the cornea Ec of the subject's eye E 4, an alignment index image based on the corneal reflected light of the alignment index by the index projection optical system 40 and an alignment bright spot image i1 (see FIG. 4) based on the corneal reflected light of the alignment index by the front projection optical system 30a are formed. state.

FIG. 4 shows the position where the alignment bright spot image i1 is formed in the subject's eye E, the anterior segment image 80 captured by the anterior segment observation optical system 30b, and the endothelial cell image 90 captured by the corneal imaging optical system 10. It is a figure which shows typically. FIG. 4A shows a state in which the line of sight of the subject's eye E is guided in the front direction. FIG. 4B shows a state in which the line of sight of the subject's eye E is guided in the peripheral direction (downward direction here). The cornea Ec includes an alignment bright spot image i1 based on the corneal reflected light of the alignment index by the alignment optical system 30 and an alignment index image n1 (alignment index image n1) based on the corneal reflected light of the alignment index by the first projection optical system 40a. index images n1a and n1b) and an alignment index image n2 (that is, alignment index images n2a, n2b, n2c, and n2d) based on the cornea-reflected light of the alignment index by the second projection optical system 40b are respectively formed. However, for the sake of convenience, illustration of the alignment index images n1 and n2 is omitted.

On the subject's eye E, a first alignment bright spot image i1 formed by the front projection optical system 30a is formed as a first alignment bright spot image i1 based on the corneal front surface reflected light in which the alignment index is reflected by the front surface Ec1 of the cornea Ec (hereinafter referred to as the corneal front surface Ec1). An image i1a is formed. The first alignment bright spot image i1a is formed on a straight line that is parallel to the optical axis L1 and passes through the curvature center Pa of the corneal anterior surface Ec1 (hereinafter referred to as the front surface curvature center Pa). Further, on the subject's eye E, a second alignment image based on the corneal rear surface reflected light in which the alignment index is reflected by the rear surface Ec2 of the cornea Ec (hereinafter referred to as the corneal rear surface Ec2) is projected as an alignment bright point image i1 by the front projection optical system 30a. A bright spot image i1b is formed. The second alignment bright spot image i1b is formed on a straight line that is parallel to the optical axis L1 and passes through the center of curvature Pb of the corneal posterior surface Ec2 (hereinafter referred to as the posterior surface curvature center Pb). The luminance of the second alignment luminescent spot image i1b is about 1/100 of the luminance of the first alignment luminescent spot image i1a.

When the line of sight of the subject's eye E is in the front direction as shown in FIG. 4A, the subject's eye E is not rotated. For example, when the subject's eye E is caused to fixate on the fixation lamp 61a of the internal fixation optical system 60a, the subject's eye E is not rotated. In this case, since the front curvature center Pa and the back curvature center Pb of the eye E are coaxially positioned, the first alignment bright spot image i1a and the second alignment bright spot image i1b are coaxially formed. On the anterior segment image 80, the first alignment luminescent point image i1a and the second alignment luminescent point image i1b overlap, and it is observed that there is only the first alignment luminescent point image i1a.

As shown in FIG. 4B, when the line of sight of the subject's eye E is downward at a predetermined angle θ, the subject's eye E is rotated. As an example, when the eye to be examined E is caused to fixate on the fixation lamp 64d of the external fixation optical system 60b, the eye to be examined E is rotated. In this case, the front surface curvature center Pa and the rear surface curvature center Pb of the eye to be examined E are not coaxially positioned, and the second alignment bright spot image i1b is shifted downward by the shift amount Δd with respect to the first alignment bright spot image i1a. formed by Therefore, both the first alignment luminescent spot image i1a and the second alignment luminescent spot image i1b are observed on the anterior segment image 80 .

In the conventional alignment operation, the alignment reference position K for aligning the corneal imaging optical system 10 with respect to the eye E to be inspected is set to the position of the first alignment bright spot image i1a based on the reflected light from the front surface of the cornea. An endothelial cell image was captured in a state in which the alignment reference position K and the optical axis L1 were substantially aligned. In this case, if the line of sight of the subject's eye E is in the front direction, the posterior corneal surface Ec2 is appropriately arranged with respect to the optical axis L1. As an example, the tangent line N1 that intersects the optical axis L1 of the posterior corneal surface Ec2 is substantially perpendicular to the optical axis L1. Therefore, in the corneal imaging optical system 10, when the illumination light emitted along the optical axis L2 from the illumination light source 11 is reflected by the corneal posterior surface Ec2, the reflected light travels along the optical axis L3, and the image sensor 22 is imaged. As a result, the endothelial cell image 90 is captured with uniform brightness in the center and the periphery.

On the other hand, when the line of sight of the subject's eye E is directed downward, the posterior corneal surface Ec2 may not be appropriately arranged with respect to the optical axis L1. As an example, the tangent line N1 that intersects the optical axis L1 of the posterior surface of the cornea Ec2 may not be substantially perpendicular to the optical axis L1, but may be inclined. Therefore, in the corneal imaging optical system 10, when the illumination light emitted from the illumination light source 11 along the optical axis L2 is reflected by the corneal posterior surface Ec2, the reflected light travels off the optical axis L3 and travels partially. Light is no longer picked up by the imaging device 22 . As a result, the brightness of the endothelial cell image 90 becomes non-uniform, and the periphery is captured dark.

In the conventional XY direction alignment operation, as described above, there are cases where the endothelial cell image 90 cannot be satisfactorily captured. In this embodiment, the difference due to the line-of-sight direction of the eye to be inspected E is taken as an example, but the present invention is not limited to this. Similarly, when the endothelial cell image 90 cannot be captured satisfactorily in a mutually eccentric state (for example, when the subject's eye E has undergone refractive surgery such as LASIK, when the subject's eye E has a corneal disease, etc.) was there.

Therefore, in this embodiment, in the alignment operation in the XY directions, the alignment reference position K is set to the position of the second alignment bright spot image i1b based on the corneal rear surface reflected light, and the alignment reference position K and the optical axis L1 are substantially aligned. Endothelial cell images are taken in the state of For example, according to this, the endothelial cell image 90 can be satisfactorily captured at a position where the tangent line N1 where the posterior corneal surface Ec2 intersects the optical axis L1 is substantially perpendicular to the optical axis L1.

<Control operation>
A control operation of the imaging apparatus 100 for capturing a corneal endothelial cell image will be described below with reference to the flowchart shown in FIG.

<Capturing an image of the anterior segment of the eye to be examined>
The examiner instructs the subject to fixate on the fixation light. First, the CPU 71 turns on the fixation lamp 61a in the internal fixation optical system 60a (S1). Thereby, the eye E to be examined is presented with the fixation lamp 61a.

Next, the CPU 71 turns on the anterior segment observation light source (not shown). The image processing IC 75 processes a signal output from the imaging device 22 of the anterior eye observation optical system 30b to generate an anterior eye image 80 of the subject's eye and output the anterior eye image 80 to the monitor 7. (S2). In this embodiment, the image processing IC 75 sequentially forms an anterior segment image 80 and sequentially displays it on the monitor 7 . In other words, the image processing IC 75 displays the anterior segment image 80 on the monitor 7 as a live image.

<Alignment between eye to be examined and imaging unit>
The CPU 71 uses the anterior segment image 80 to perform alignment processing of the imaging unit 1 with respect to the eye E to be examined. The CPU 71 turns on the infrared light source 31 in the front projection optical system 30a. The CPU 71 also turns on the infrared light sources 41a and 41b in the first projection optical system 40a and the infrared light sources 43a to 43d in the second projection optical system 40b. The CPU 71 also turns on the illumination light source 51 in the working distance detection optical system 50 .

FIG. 6 is an example of an anterior segment image 80 displayed on the monitor 7 . FIG. 6A shows a state in which the photographing unit 1 is displaced with respect to the subject's eye (that is, a state in which there is misalignment). FIG. 6B shows a state in which the photographing unit 1 is not displaced with respect to the subject's eye (that is, a state in which there is no misalignment). The anterior segment image 80 includes a first alignment bright spot image i1a from the front projection optical system 30a, alignment index images n1a and n1b from the first projection optical system 40a, and alignment index images from the second projection optical system 40b. n2a to n2d are formed.

The CPU 71 performs alignment in the XY directions using the alignment index images n2a to n2d from the second projection optical system 40b and the first alignment bright spot image i1a from the front projection optical system 30a (S3). In this alignment, an alignment reference position K is set at the position of the first alignment luminescent spot image i1a, and the first alignment luminescent spot image i1a (alignment reference position K) is aligned with the optical axis L1. The CPU 71 detects the alignment index images n2a to n2d, and detects the center position of the rectangle formed by these alignment index images as the approximate corneal apex position Mo of the eye E to be examined.

FIG. 7 is a diagram for explaining alignment control. FIG. 7(a) shows the alignment of the approximate corneal vertex position Mo with respect to the reticle R. FIG. FIG. 7B shows the alignment of the first alignment bright spot image i1a with respect to the reticle R. FIG. The CPU 71 detects the misalignment direction and deviation amount Δq1 in the XY directions of the approximate corneal vertex position Mo with respect to the reticle R representing the center position of the optical axis L1 electronically displayed on the anterior segment image 80. . Further, the CPU 71 moves the photographing unit 1 in the XY directions so that the deviation amount Δq1 falls within the allowable range A1. As a result, the first alignment bright spot image i1a is detected on the anterior segment image 80 .

Subsequently, the CPU 71 detects the direction of misalignment in the XY directions of the first alignment bright spot image i1a with respect to the reticle R and the deviation amount Δq2. Further, the CPU 71 moves the photographing unit 1 in the XY directions so that the deviation amount Δq2 is within the allowable range. As a result, the state shown in FIG. 6A changes to the state shown in FIG. 6B, and the alignment in the XY directions is completed.

The CPU 71 also performs alignment in the Z direction using the alignment index images n1a and n1b from the first projection optical system 40a and the alignment index images n2a to n2d from the second projection optical system 40b (S4). When the first alignment bright spot image i1a is detectable, the alignment index images n1a and n1b are also detectable. Alignment index images n1a and n1b are at infinity, and alignment index images n2a to n2d are at finite distance. Therefore, for example, when the photographing unit 1 is displaced in the Z direction with respect to the subject's eye E, the interval between the alignment index images n1a and n1b hardly changes, but the interval between the alignment index images n2a and n2b and the alignment index image n2c and n2d spacings vary. The CPU 71 compares the interval between the alignment index images n1a and n1b and the interval between the alignment index images n2a and n2b (or the interval between the alignment index images n2c and n2d) to determine the direction/bias of misalignment in the Z direction. The position amount is detected, and the photographing unit 1 is moved in the Z direction so that the misalignment falls within the allowable range. For details on this, refer to Japanese Patent Application Laid-Open No. 6-46999.

The CPU 71 also uses the light detected by the working distance detection optical system 50 to perform alignment in the Z direction. FIG. 8 is a diagram showing epithelial peaks detected by the detector 57. FIG. The CPU 71 controls the driving section 5 based on the signal output from the detector 54 to move the photographing section 1 in the Z direction. For example, the CPU 71 detects the peak P corresponding to the reflected light from the corneal epithelium in the waveform indicating the intensity distribution of the corneal reflected light in the depth direction, based on the intensity distribution indicated by the output signal from the detector 54. . The drive unit 5 is driven so that the position Pz of the epithelial peak on the detector 54 becomes the position of a predetermined pixel (for example, the position of the center pixel) of the detector 54 . As a result, in the imaging device 100, the focus of the corneal imaging optical system 10 is set to the corneal epithelium or its vicinity. Alignment in the Z direction is performed as described above.

<Gaze Guidance of Subject's Eye E>
When the XYZ alignment of the photographing unit 1 with respect to the eye E to be examined is completed, the examiner turns on the fixation lamp to guide the line of sight of the eye E to be examined. The examiner operates the monitor 7 (operation input unit 76) to specify the lighting position of the fixation lamp. The CPU 71 changes the lighting position of the fixation lamp according to the signal input from the monitor 7 (S5).

For example, in this embodiment, the CPU 71 turns on the fixation lamp 64d of the external fixation optical system 60b in order to guide the line of sight of the subject's eye E downward. Thereby, the eye E to be examined is presented with the fixation lamp 64d. Further, since the line of sight of the eye to be examined E is directed downward, the anterior segment image 80 of the eye to be examined E includes the first alignment bright point image i1a and the second alignment bright point image i1b by the front projection optical system 30a. becomes observed.

<Detection of Alignment Bright Spot Image>
The CPU 71 detects the first alignment bright spot image i1a by analyzing the anterior segment image 80 (S6). For example, the CPU 71 performs edge detection as analysis processing on the anterior segment image 80 and detects the rise and fall of luminance, thereby detecting the first alignment bright spot image i1a. Of course, the analysis processing is not limited to edge detection, and any configuration capable of detecting the first alignment bright spot image i1a may be used.

When detecting the first alignment luminescent point image i1a from the anterior segment image 80, the CPU 71 sets a detection area for detecting the second alignment luminescent point image i1b based on the first alignment luminescent point image i1a (S7 ). For example, the detection area may be set around the first alignment luminescent spot image i1a with the first alignment luminescent spot image i1a as the center. Further, for example, the detection area may be set at a predetermined position with respect to the first alignment bright spot image i1a. In this embodiment, a case where the detection area is set at a predetermined position with respect to the first alignment luminescent spot image i1a will be exemplified.

FIG. 9 shows an example of the detection area S set based on the first alignment luminescent spot image i1a. FIG. 9A shows a state in which the eye E to be examined is presented with the fixation lamp 64a. FIG. 9B shows a state in which the eye E to be examined is presented with the fixation lamp 64d. The direction in which the second alignment luminescent point image i1b is formed on the cornea Ec of the eye E to be examined can be predicted from the presentation position of the fixation lamp with respect to the eye E to be examined (in other words, the line-of-sight direction of the eye E to be examined). For example, as shown in FIG. 9A, when the fixation lamp 64a is presented to the eye E to be examined (that is, when the line of sight of the eye E to be examined is directed upward), the first alignment brightness A second alignment bright point image i1b is formed above the point image i1a. Further, for example, as shown in FIG. 9B, when the fixation lamp 64d is presented to the eye E to be examined (that is, when the line of sight of the eye E to be examined is directed downward), the first A second alignment luminescent spot image i1b is formed below the alignment luminescent spot image i1a.

Further, the position where the second alignment bright point image i1b is formed on the cornea Ec of the eye E to be examined can be predicted from the presentation angle of the fixation lamp with respect to the eye E to be examined. For example, the smaller the presentation angle of the fixation lamp, the closer the second alignment luminescent spot image i1b is to the first alignment luminescent spot image i1a. A second alignment bright spot image i1b is formed at a position far from i1a. As an example, in the state in which the fixation lamp 61c is presented to the subject's eye E and the state in which the fixation light 64a is presented to the eye E, the state in which the fixation lamp 64a is presented is positioned farther from the first alignment luminescent spot image i1a than the second position. An alignment bright spot image i1b is formed.

Therefore, the direction and position in which the second alignment luminescent spot image i1b is formed may be associated in advance with the presentation position and presentation angle of the fixation lamp based on experiments, simulations, etc., and stored in the ROM 93 . The CPU 71 sets a detection region S corresponding to the presentation position and presentation angle of the fixation lamp with respect to the eye E to be examined, for the first alignment bright spot image i1a. In addition, in FIG. 9, the detection area S has a rectangular shape, but it can have various shapes. Also, the detection region S may be the upper half (lower half) of the anterior segment image 80, or the like.

The CPU 71 analyzes the anterior segment image 80 to detect the second alignment bright spot image i1b from the detection area S set based on the first alignment bright spot image i1a (S8). The CPU 71 may detect the second alignment luminescent spot image i1b by edge detection, similar to the detection of the first alignment luminescent spot image i1a.

Note that the anterior segment image 80 includes a third alignment bright spot image (not shown) based on light reflected from the front surface of the lens of the eye E to be inspected and the alignment index reflected by the front surface of the lens of the eye to be inspected E, as an alignment bright spot image i1. A fourth alignment bright spot image (not shown) is also formed based on the reflected light from the back surface of the crystalline lens that is reflected by the alignment index on the posterior surface of the crystalline lens of E. Of these, the fourth alignment luminescent point image is approximately the same size as the second alignment luminescent point image i1b, and is formed at substantially the same position in the Z direction, making it difficult to distinguish them from each other. Also, the fourth alignment luminescent point image is formed in the same direction as the XY directions in which the second alignment luminescent point image i1b is formed with respect to the first alignment luminescent point image i1a. However, the position in the XY direction where the fourth alignment luminescent spot image is formed differs greatly from the position in the XY direction where the second alignment luminescent spot image i1b is formed. is appropriately set, the possibility of erroneously detecting the fourth alignment luminescent spot image when detecting the second alignment luminescent spot image i1b is reduced.

<Setting the alignment reference position>
When detecting the second alignment luminescent point image i1b, the CPU 71 sets an alignment reference position K for aligning the corneal imaging optical system 10 with respect to the subject's eye E based on the position of the second alignment luminescent point image i1b. (S9). In this embodiment, in step S3, the eye to be examined E faces the front direction, and the alignment reference position K is set at the position of the first alignment luminescent spot image i1a. , and the alignment reference position K is changed to the position of the second alignment bright spot image i1b.

Subsequently, the CPU 71 executes alignment for matching (substantially matching) the second alignment luminescent spot image i1b set as the alignment reference position K and the central axis L1. FIG. 10 is a diagram for explaining alignment control based on the position of the second alignment luminescent spot image i1b. 10A shows the alignment of the second alignment bright spot image i1b with respect to the reticle R. FIG. FIG. 10B is an example of an anterior segment image 80 displayed on the monitor 7 . The CPU 71 detects the misalignment direction and the deviation amount Δq3 in the XY directions of the second alignment bright spot image i1b with respect to the reticle R displayed on the anterior segment image 80 . Further, the CPU 71 moves the photographing unit 1 in the XY directions so that the deviation amount Δq3 is within the allowable range A3. As a result, the relative positions of the subject's eye E and the photographing unit 1 in the XY directions are adjusted, and on the anterior eye image 80, the second alignment bright spot image i1b is aligned with the reticle R (optical axis center position of L1).

<Photography of endothelial cell images>
After setting the alignment reference position K, the CPU 71 captures an endothelial cell image 90 of the eye E to be examined. The CPU 71 turns on the illumination light source 11 of the corneal imaging optical system 10 . The image processing IC 75 processes the signal output from the imaging element 22 of the corneal imaging optical system 10 to generate an endothelial cell image 90 of the subject's eye and output the endothelial cell image 90 to the monitor 7 (S10). By these operations, the endothelial cell image 90 of the subject's eye E is captured satisfactorily.

In this embodiment, when capturing a corneal endothelial cell image, the internal fixation lamp 61a is turned on to perform alignment in the XY and Z directions, and then the external fixation lamp 64d is turned on to perform the first alignment. Although the configuration for detecting the luminescent spot image i1a and the second alignment luminescent spot image i1b has been described as an example, the present invention is not limited to this. For example, when capturing a corneal endothelial cell image, the external fixation lamp is turned on to perform alignment in the XY and Z directions, and then the first alignment bright spot image i1a and the second alignment bright spot image i1b are detected. It is good also as a structure which carries out.

As described above, for example, the corneal endothelial cell imaging apparatus according to the present embodiment includes the first alignment bright spot image based on the corneal reflected light from the anterior surface of the cornea of the subject's eye and the corneal reflection from the posterior surface of the cornea of the subject's eye. a second alignment luminescent spot image based on light; and detecting at least the second alignment luminescent spot image, and aligning the corneal imaging optical system with the subject's eye based on the second alignment luminescent spot image. Set the alignment reference position. By adjusting the relative positions of the eye to be inspected and the corneal imaging optical system based on the second alignment bright spot image, the endothelial cell image can be obtained with the posterior surface of the cornea appropriately arranged with respect to the optical axis. Images can be taken. As a result, the brightness of the endothelial cell image becomes uniform between the central portion and the peripheral portion, and a good image can be obtained in which the darkening of the peripheral portion is suppressed.

Further, for example, the corneal endothelial cell imaging apparatus in the present embodiment sets an alignment reference position for aligning the imaging optical system with respect to the eye to be inspected based on the second alignment bright spot image, and sets the alignment reference position. Based on this, the relative position between the subject's eye and the imaging optical system is adjusted. As a result, the second alignment luminescent spot image can always be detected, the second alignment luminescent spot image can be matched (substantially matched) with the optical axis, and the posterior surface of the cornea can be arranged more appropriately with respect to the optical axis. .

Further, for example, the corneal endothelial cell imaging apparatus in the present embodiment detects the first alignment luminescent spot image, and also detects the second alignment luminescent spot image based on the first alignment luminescent spot image. The second alignment luminescent spot image is formed around the first alignment luminescent spot image, but its brightness is low and it is difficult to detect. By using the first alignment luminescent spot image as a guide, the second alignment luminescent spot image can be efficiently detected.

Further, for example, the corneal endothelial cell imaging apparatus in the present embodiment sets a detection region for detecting the second alignment luminescent spot image, detects the second alignment luminescent spot image from within the detection region, and detects the second alignment luminescent spot image. Set the alignment reference position based on the bright spot image. As described above, the brightness of the second alignment luminescent spot image is low and is difficult to detect. However, by setting the detection area in advance, the second alignment luminescent spot image can be detected more efficiently. Moreover, by setting the detection area in advance, the possibility of erroneously detecting an image different from the second alignment bright spot image is reduced.

Further, for example, the corneal endothelial cell imaging apparatus in this embodiment sets a detection area for detecting the second alignment bright spot image around the first alignment bright spot image. Since the second alignment luminescent spot image is formed around the first alignment luminescent spot image, by setting a detection region in advance around the first alignment luminescent spot image, the second alignment luminescent spot image can be formed differently from the second alignment luminescent spot image. It is possible to suppress erroneous image detection and efficiently detect the second alignment bright spot image.

Further, for example, the corneal endothelial cell imaging apparatus in this embodiment sets a detection region for detecting the second alignment bright spot image based on the presentation position of the fixation target with respect to the eye to be examined. For example, the position where the second alignment luminescent spot image is formed changes depending on the line-of-sight direction of the subject's eye. Therefore, it is possible to predict the position where the second alignment luminescent spot image is formed from the presentation position of the fixation target presented to the eye to be inspected, and set the detection area to be small. Efficient detection.

<transformation example>
In this embodiment, an anterior segment image 80 of the eye to be inspected E, which is obtained by imaging the signal from the imaging device 35 in the anterior segment observation optical system 30b by the image processing IC 75, is used to obtain the corneal reflected light of the eye to be inspected E. Although the configuration for detecting the alignment luminescent spot image i1 based on the above has been described as an example, the present invention is not limited to this. For example, a configuration may be adopted in which the alignment bright spot image i1 based on the corneal reflected light of the eye E to be inspected is detected by using the signal on the imaging surface of the imaging element 35 as it is.

In this embodiment, both the first alignment bright spot image i1a based on the front corneal reflected light of the eye E to be inspected and the second alignment bright spot image i1b based on the back corneal reflected light of the eye E to be inspected are both detected. Although the configuration has been described as an example, it is not limited to this. In the present embodiment, it is sufficient to detect at least the second alignment luminescent point image i1b out of the first alignment luminescent point image i1a and the second alignment luminescent point image i1b. In other words, the configuration may be such that only the second alignment luminescent spot image i1b is detected. For example, in this case, by setting the detection region S according to the presentation position and presentation angle of the fixation lamp with respect to the eye E, the second alignment image can be obtained without using the first alignment bright spot image i1a. A bright spot image i1b may be detected.

In this embodiment, the configuration for setting the detection area S for detecting the second alignment luminescent spot image i1b has been described as an example, but the configuration is not limited to this. For example, the detection area S may not necessarily be provided, and in this case, the position with the next highest luminance to the first alignment luminescent spot image i1a may be detected as the second alignment luminescent spot image i1b.

In this embodiment, in order to adjust the relative position between the subject's eye E and the imaging unit 1 (corneal imaging optical system 10), the position of the second alignment bright spot image i1b detected from the anterior segment image 80 is Based on this, the alignment reference position K is set, and the photographing unit 1 is moved in the XY directions so that the alignment reference position K is aligned with the reticle R displayed at the center position of the optical axis L1. It is not limited to this. In order to adjust the relative position between the subject's eye E and the imaging unit 1, the position of the reticle R displayed on the anterior segment image 80 may be moved. That is, the display on the reticle R may be moved to a position different from the central position of the optical axis L1. In this case, in the anterior segment image 80, the amount of deviation in the XY direction of the second alignment bright point image i1b with respect to the first alignment bright point image i1a is detected, and the position of the reticle R is moved based on this amount of deviation. be. For example, the photographing unit 1 may be moved in the XY directions so that the first alignment luminescent spot image i1a is aligned with the reticle R, thereby aligning the second alignment luminescent spot image i1b with the optical axis L1.

In this embodiment, the alignment reference position K is set to the second alignment bright spot image i1b in a state in which the fixation lamp provided in the external fixation optical system 60b is turned on to guide the line of sight of the eye E to be examined. Although described as an example, it is not limited to this. Of course, the fixation lamps (for example, the fixation lamps 61b to 61i) of the internal fixation optical system 60a are turned on to guide the line of sight of the subject's eye E. may be set. However, when using the fixation lamps 61b to 61i of the internal fixation optical system 60a, it is not always necessary to set the alignment reference position K to the second alignment bright spot image i1b.

For example, in the present embodiment, when the subject's eye E fixes its eyes on the fixation lights 64a to 64f of the external fixation optical system 60b, the presentation angle of the fixation lights with respect to the subject's eye E is about 25 degrees, and the first alignment The shift amount Δd of the second alignment luminescent spot image i1b with respect to the luminescent spot image i1a is large. On the other hand, when the subject's eye E fixes its eyes on the fixation lamps 61b to 61i of the internal fixation optical system 60a, the presentation angle of the fixation target with respect to the subject's eye E is about 5 degrees, and the first alignment bright point image i1a The shift amount Δd of the second alignment luminescent spot image i1b with respect to is small. Therefore, when using the fixation lamps 61b to 61i of the internal fixation optical system 60a, the alignment reference position K may be set to the first alignment bright spot image i1a.

That is, the photographing apparatus 100 is configured such that when the fixation light is presented to the subject's eye E at a presentation position for capturing an endothelial cell image in the center of the cornea Ec (in other words, when the fixation light for the subject's eye E is less than a predetermined angle), the first alignment luminescent spot image i1a may be detected and the alignment reference position K based on the first alignment luminescent spot image i1a may be set. In addition, the photographing apparatus 100 is configured such that when the fixation light is presented to the subject's eye E at a presentation position for capturing an endothelial cell image in the peripheral portion of the cornea Ec (in other words, when the fixation light for the subject's eye E is a predetermined angle or more), the second alignment luminescent spot image i1b may be detected and the alignment reference position K based on the second alignment luminescent spot image i1b may be set. With such a configuration, even when capturing an endothelial cell image in the peripheral portion of the cornea Ec of the subject's eye E, the posterior corneal surface Ec2 is appropriately arranged with respect to the optical axis L1, and the endothelial cell image can be captured satisfactorily. can do.

In the above description, whether alignment is performed using the first alignment luminescent spot image i1a or alignment using the second alignment luminescent spot image i1b is changed based on the presentation position of the fixation lamp. but not limited to this. For example, based on the angle θ of the line-of-sight direction of the eye to be inspected E (that is, the angle between the visual axis of the eye to be inspected E and the optical axis L1), either the first alignment luminescent spot image i1a or the second alignment luminescent spot image i1b is determined. Whether to use it may be switched. As an example, a threshold is set for the angle θ within a range of 5 degrees to 25 degrees, and the first alignment luminescent spot image i1a is used when the angle θ is less than the threshold, and the second alignment image i1a is used when the angle θ is greater than or equal to the threshold. A configuration using the alignment bright spot image i1b may also be used. Such a threshold may be set to an arbitrary value by the examiner, or may be set to a predetermined value in advance.

In this embodiment, as described above, the luminance of the second alignment luminescent spot image i1b is only about 1/100 of the luminance of the first alignment luminescent spot image i1a. Undetected can happen. Therefore, when the line of sight of the subject's eye E is guided in the peripheral direction, the detected light amount of the second alignment luminescent spot image i1b may be adjusted so that the second alignment luminescent spot image i1b is easily detected. As an example, the amount of light detected by the imaging device 35 may be increased by increasing the amount of light emitted from the infrared light source 31 of the anterior segment observation optical system 30b. Further, as an example, the amount of light detected by the image sensor 35 may be increased by increasing the gain of the image sensor 35 . Of course, both the adjustment of the amount of light in the infrared light source 31 and the adjustment of the gain in the imaging element 35 may be performed.

For example, such adjustment of the amount of light detected by the second alignment luminescent spot image i1b may be performed at any timing by the examiner, or may be automatically adjusted when the fixation lamp that causes the eye to be examined E to fixate is turned on. may The configuration may be such that the adjustment is performed automatically when the second alignment bright spot image i1b is not detected. This makes it possible to efficiently detect the second alignment luminescent spot image whose luminance is lower than that of the first alignment luminescent spot image.

Note that the technology disclosed in this embodiment is not limited to application to the apparatus exemplified in this embodiment. For example, the terminal control software (program) that performs the functions of the above embodiments is supplied to a system or device via a network or various storage media, and a control device (e.g., CPU, etc.) of the system or device executes the program. It is also possible to read and execute.

10 Corneal Imaging Optical System 30 Alignment Optical System 30a Front Projection Optical System 30b Anterior Segment Observation Optical System 40 Index Projection Optical System 50 Working Distance Detection Optical System 60 Fixation Optical System 70 Control Unit 100 Corneal Endothelial Cell Imaging Device

Claims (5)

An imaging optical system for capturing an endothelial cell image of the cornea by projecting illumination light emitted from a first light source onto the cornea of the subject's eye and detecting corneal reflected light of the illumination light with a first detector. and,
An alignment index for the XY directions emitted from a second light source is projected toward the cornea, and corneal reflected light from the alignment index is passed through an objective lens arranged in the front direction of the subject's eye to a second detector. an alignment optical system for detection;
A corneal endothelial cell imaging device having
A first alignment bright spot based on the corneal reflected light from the anterior surface of the cornea and a second alignment bright spot based on the corneal reflected light from the posterior surface of the cornea, based on the detection signal from the second detector. setting means for detecting at least the second alignment luminescent spot;
alignment control means for adjusting a relative position between the eye to be inspected and the imaging optical system based on the second alignment luminescent spot so that the second alignment luminescent spot coincides with the optical axis of the objective lens;
A corneal endothelial cell imaging device comprising: In the corneal endothelial cell imaging device of claim 1,
The setting means sets an alignment reference position for aligning the imaging optical system with the eye to be inspected based on the second alignment bright spot,
The corneal endothelial cell imaging apparatus, wherein the alignment control means adjusts a relative position between the eye to be inspected and the imaging optical system based on the alignment reference position. In the corneal endothelial cell imaging device of claim 1 or 2,
The corneal endothelial cell imaging apparatus, wherein the setting means detects the second alignment luminescent spot based on the first alignment luminescent spot. In the corneal endothelial cell imaging device according to any one of claims 1 to 3,
The setting means sets a detection area for detecting the second alignment luminescent spots, detects the second alignment luminescent spots from within the detection area, and determines the alignment reference position based on the second alignment luminescent spots. A corneal endothelial cell imaging apparatus characterized by setting An imaging optical system for capturing an endothelial cell image of the cornea by projecting illumination light emitted from a first light source onto the cornea of the subject's eye and detecting corneal reflected light of the illumination light with a first detector. and,
An alignment index for the XY directions emitted from a second light source is projected toward the cornea, and corneal reflected light from the alignment index is passed through an objective lens arranged in the front direction of the subject's eye to a second detector. an alignment optical system for detection;
A corneal endothelial cell imaging program used in a corneal endothelial cell imaging apparatus having
By being executed by the processor of the corneal endothelial cell imaging device,
A first alignment bright spot based on the corneal reflected light from the anterior surface of the cornea and a second alignment bright spot based on the corneal reflected light from the posterior surface of the cornea, based on the detection signal from the second detector. a setting step of detecting at least the second alignment luminescent spot;
an alignment control step of adjusting the relative position between the subject eye and the imaging optical system based on the second alignment luminescent spot so that the second alignment luminescent spot coincides with the optical axis of the objective lens;
A corneal endothelial cell imaging program characterized by causing the corneal endothelial cell imaging apparatus to execute.

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