JP2014023854A - Cornea inspection equipment - Google Patents

Abstract

An object of the present invention is to provide a corneal endothelial cell imaging apparatus 1 that can perform effective alignment of the cornea to the endothelium without changing the line-of-sight direction of the eye to be examined.
[Solution]
The apparatus 1 includes an inspection optical unit 20 having an anterior ocular segment observation optical system 23 and a cornea imaging optical system 22, a linear drive mechanism and a turning drive mechanism for moving the inspection optical unit, and an inspection optical unit. A control unit 15 for controlling the driving of the inspection optical unit by the linear drive mechanism and the turning drive mechanism, and the control unit includes a test position specifying unit 15a and a specified target. And a normal direction calculation unit 15b of the test site, and this control unit causes the optical reference axis S of the test optical unit to be along the normal line in the designated test site and based on luminance information of the corneal endothelium image. The inspection optical unit is configured to control the drive by the linear drive mechanism and the turning drive mechanism for aligning the inspection optical unit with the designated test site of the corneal endothelium.
[Selection] Figure 5

Description

  The present invention relates to a cornea inspection device. More specifically, the present invention relates to a corneal examination apparatus including a corneal cell photographing apparatus for observing and photographing corneal cells by a specular method. Here, the specular imaging device is a device that irradiates illumination light from the front of the optical axis of the eye to be examined, receives specular reflection light from the cornea from the front, and observes and shoots this image. is there.

  As such a specular corneal inspection apparatus, one disclosed in Japanese Patent Application Laid-Open No. 2008-246071 is known. This corneal cell imaging apparatus includes a plurality of peripheral fixation lamps. When the peripheral part of the cornea of the eye to be examined is photographed by this corneal examination apparatus, the optical axis of the examination optical part is aligned with the photographing part. Specifically, the visual axis of the eye to be examined is rotated and fixed in the designated direction by the subject fixing the appropriately designated fixation lamp among the plurality of peripheral fixation lamps. . Thereby, the imaging target part on the eye to be examined is directed to the front of the apparatus, and the part is imaged.

  However, in the corneal examination apparatus, since the installation positions of the plurality of fixation lamps are fixed, only a predetermined part of the surface of the eye to be examined can be imaged. With this corneal examination apparatus, it is not possible to image an arbitrary part on the eye to be examined. In addition, the subject may feel pain because it is necessary to move the line of sight to a different fixation lamp every time photographing is performed. It is not easy to fixate by rotating the line of sight largely, and there is a risk that fixation will be inaccurate.

JP 2008-246071 A

  The present invention has been made in view of the above-described situation, and an object of the present invention is to provide a cornea inspection apparatus that can inspect an arbitrary part on the cornea without the need for the eye to change the direction of the line of sight. It is said.

The cornea inspection device of the present invention is
An inspection optical unit having an anterior ocular segment observation optical system and a cornea photographing optical system;
A linear drive mechanism for linearly moving the inspection optical unit;
A turning drive mechanism for turning and moving the inspection optical unit;
A control unit for controlling the movement drive of the inspection optical unit by the linear drive mechanism and the turning drive mechanism in order to align the inspection optical unit with a designated position of the eye to be examined; and
The control unit includes a test position specifying unit that specifies a test site on the anterior segment image, and a normal direction calculation unit that calculates the normal of the specified test site,
Control by this control unit
Control of the drive by the linear drive mechanism and the turning drive mechanism in order to align the optical reference axis of the inspection optical unit with the normal line in the designated test site;
Control of driving by a linear drive mechanism for aligning and focusing the inspection optical unit with respect to the designated test site of the corneal endothelium based on the luminance information of the corneal endothelium image obtained by the corneal imaging optical system. And.

Preferably, the linear drive mechanism moves the inspection optical unit in three orthogonal XYZ directions including the Z axis that coincides with the optical reference axis.
The control unit is configured so that the inspection optical unit after turning so that the optical reference axis is along the normal direction can move in an orthogonal three-axis direction of ABC including the C axis that coincides with the optical reference axis. The driving of the linear drive mechanism is controlled.

  Preferably, the control unit is configured to define a velocity vector in the orthogonal triaxial direction of the ABC as a polar coordinate and convert the velocity vector of the polar coordinate into an XYZ orthogonal triaxial velocity vector. Yes.

Preferably, the luminance information of the corneal endothelium image includes a luminance distribution of the corneal endothelium image obtained by the cornea photographing optical system,
The control unit controls driving of the linear drive mechanism to move the inspection optical unit in a direction in which the luminance distribution becomes uniform based on a change in luminance distribution of the corneal endothelium image accompanying movement of the inspection optical unit. It is configured as follows.

  Preferably, the control unit determines the luminance of the vertical luminance measurement target portions near the left and right ends of the corneal endothelium image and the luminance of the horizontal luminance measurement target portions near the upper and lower ends of the corneal endothelium image. By measuring at least one and comparing the brightness, alignment based on the uniformity of the brightness distribution is determined.

  According to the corneal examination apparatus of the present invention, even when examining a plurality of different parts of the eye to be examined, the eye to be examined does not need to change the direction of the line of sight. Furthermore, effective alignment to the endothelium of the cornea is possible.

FIG. 1 is a side view schematically showing one embodiment of a cornea inspection device according to the present invention. FIG. 2 is a front view of the cornea inspection device of FIG. FIG. 3 is a side view showing the vertical in-plane rotation of the main body of the cornea inspection device of FIG. FIG. 4 is a plan view showing the horizontal rotation of the main body of the cornea inspection device of FIG. FIG. 5 is an optical path diagram showing an inspection optical unit arranged in the main body of the cornea inspection apparatus of FIG. FIG. 6A is a front view showing the anterior segment of the eye to be examined, the corneal apex, and the designated imaging point, and FIG. 6B is a sectional view taken along the line VI-VI. FIG. 7 is a diagram for explaining the mismatch between the eye axis and the visual axis of the eye to be examined at the time of the reference alignment, and FIG. 7A shows the eye to be examined in which the eye axis and the visual axis do not match. FIG. 7B shows an eye to be examined in which the eye axis coincides with the visual axis. FIG. 8 is a diagram showing a change in the imaging position of the Purkinje image due to the rotation of the inspection optical unit. FIG. 8A shows the imaging position of the Purkinje image at the time of reference alignment, and FIG. The imaging position of the Purkinje image after an optical part swivels is shown. FIG. 9 is a side sectional view of the eye to be examined for explaining the procedure for alignment to the corneal endothelium. FIG. 9A shows an optical path in the eye to be examined at the time of reference alignment, and FIG. The optical path in the eye to be examined after the optical part is turned is shown. FIG. 10 is a diagram showing an image of slit light reflected by the cornea and received by the receiver of the cornea photographing optical system. FIGS. 11A to 11E are diagrams each showing an example of a simulated corneal image obtained by the cornea photographing optical system. FIGS. 12A to 12E are diagrams each showing an example of a simulated corneal image obtained by the cornea photographing optical system. FIG. 13 is an optical path diagram illustrating another example of the inspection optical unit of the cornea inspection device.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  The corneal examination apparatus shown in FIGS. 1 to 5 captures corneal endothelial cells in an arbitrary part of the anterior segment of the subject's eye without positional restrictions and without having to move the subject's line of sight. 1 is a corneal endothelial cell imaging device (hereinafter, also simply referred to as “device”) 1 devised to achieve this.

[Description of Drive Mechanism of Corneal Examination Apparatus 1]
As shown in FIGS. 1 and 2, the apparatus 1 has a main body 10 mounted on an XYZ table (also referred to as a triaxial mount) 2 as a linear drive mechanism. The main body 10 houses an inspection optical unit 20 (see FIG. 5) for observing and photographing corneal endothelial cells. The main body 10 is mounted on the XYZ table 2 while being supported by the support frame 3. The XYZ table 2 has a base 2a. On the base 2a, the X table 4 is installed so as to be slidable in the left-right direction (X-axis direction). On the X table 4, a Z table 6 is installed so as to be slidable in the front-rear direction (Z-axis direction). In the figure, the X axis is represented as X, the Y axis is represented as Y, and the Z axis is represented as Z. A Y table 5 is installed on the Z table 6 so as to be movable up and down in the vertical direction (Y-axis direction). As the moving mechanism in each axial direction, a mechanism such as a feed screw method can be adopted. With the above configuration, the inspection optical unit 20 can move in the XYZ orthogonal three-axis directions (left and right, up and down, front and back). The three orthogonal axes of XYZ constitute a three-dimensional coordinate. Here, the eye E side viewed from the apparatus 1 is referred to as the front, and the opposite side is referred to as the rear.

  The device 1 has a turning drive mechanism of the main body 10 separately from the linear drive mechanism. The turning drive mechanism includes an up / down turning drive mechanism 11 and a left / right turning drive mechanism 12. It is as follows. The support frame 3 has a U-shaped frame shape. The support frame 3 supports the main body 10 so as to be rotatable around the X axis (axis extending in the left-right direction). In other words, as shown in FIG. 3, the main body 10 is supported so as to be rotatable in the vertical direction. This is called rotation (turning) in the θx direction. This vertical rotation is a revolution about a reference point 30 set in front of the support frame 3. The reference point 30 is a point set on the optical reference axis S of the inspection optical unit 20 described later.

  The specific configuration of the vertical rotation drive mechanism 11 of the main body 10 is as follows. An arcuate guide groove 7 centered on the reference point 30 is formed on the side wall of the support frame 3. Three guided members 8 protruding outward from the main body 10 are in sliding contact with the edge of the guide groove 7. The main body 10 is formed with an arc-shaped rack 9 a centered on the reference point 30. A pinion gear 9b that is rotationally driven by a vertical rotation driving device 13 installed in the support frame 3 is engaged with the rack 9a. When the pinion gear 9b is rotationally driven, the main body 10 rotates around the X axis passing through the reference point 30 in the left-right direction. In FIG. 3, the optical reference axis S of the main body 10 indicated by a solid line is in a horizontal state. The main body 10 indicated by a two-dot chain line indicates a state where the main body 10 is inclined to the upper limit of the rotation range and a state where the main body 10 is inclined to the lower limit.

  FIG. 4 shows the left / right rotation drive mechanism 12. In the left-right rotation drive mechanism 12, the support frame 3 is rotatable around the Y axis passing through the reference point 30 in the vertical direction. In other words, the main body 10 is supported so as to be rotatable in the left-right direction. This is called rotation (turning) in the θy direction. The specific configuration is as follows. As shown in FIG. 1, a left-right rotation drive device 14 is provided on an extension plate portion 5 a extending in front of the Y table 5. The front portion of the support frame 3 is attached to the rotation shaft 14 a of the left-right rotation drive device 14. The rotation shaft 14 a extends upward along the Y axis passing through the reference point 30. With this configuration, the main body 10 can turn (revolve) left and right within a horizontal plane with the Z axis toward the eye E as the center.

  As described above, each rotation drive around the X axis and the Y axis of the main body 10 is automatically performed by the vertical rotation drive device 13 and the left and right rotation drive device 14.

  As shown in FIG. 5, the apparatus 1 further includes a control unit 15, a main body drive unit 16, an image processing unit 17, an operation unit 18, and a display unit 19. The control unit 15 sends a command for observing and photographing the eye E to be examined by the inspection optical unit 20 to the main body driving unit 16. Based on a command from the control unit 15, the main body drive unit 16 causes the XYZ table 2, the up / down rotation drive mechanism 11, and the left / right rotation drive mechanism 12 to move and move the main body 10. The image processing unit 17 performs image processing on the image of the eye E taken by the inspection optical unit 20. The operation unit 18 performs an operation input to the control unit 15 based on an operation by the examiner. The display unit 19 displays a captured image of the eye E to be examined by the examination optical unit 20, input items in the operation unit 18, and the like.

[Description of installation purpose of each optical system]
The inspection optical unit 20 housed in the main body 10 will be described with reference to FIG. The inspection optical unit 20 includes an illumination optical system 21, a cornea photographing optical system 22, an anterior ocular segment observation optical system 23, an alignment index projection optical system 24, and a fixation target optical system 25. The illumination optical system 21 illuminates the anterior eye portion of the eye E from an oblique front with illumination light for photographing. In this embodiment, the illumination light is slit light. Apart from the illumination optical system 21, an LED 26 that illuminates the entire anterior segment is installed at the front of the main body 10. The corneal imaging optical system 22 receives the reflected light of the illumination light from the anterior segment from an oblique front of the eye E and images the corneal endothelium of the eye E. The alignment index projection optical system 24 irradiates the alignment index light from the front toward the anterior eye portion of the eye E to be examined. The anterior ocular segment observation optical system 23 is an optical system for observing the anterior ocular segment of the eye E to be examined. The anterior ocular segment observation optical system 23 receives the anterior ocular segment and receives a bright spot (Purkinje image) as a reflection image of the alignment index light on the surface of the eye to be examined. Accordingly, the anterior ocular segment observation optical system 23 is configured to detect the corneal apex T position of the anterior ocular segment. This anterior ocular segment observation optical system 23 has a function of aligning the optical reference axis S with the corneal apex T of the eye E to be examined. The fixation target optical system 25 can fix the direction of the eye E by causing the subject to fixate the fixation lamp.

  As is apparent from FIG. 5, the optical axis (also referred to as illumination optical axis) 21a of the illumination optical system 21 and the optical axis (also referred to as imaging optical axis) 22a of the cornea photographing optical system 22 intersect each other. This intersection is referred to as “focusing point F” of the cornea photographing optical system 22. A straight line that bisects the angle formed by the illumination optical axis 21 a and the imaging optical axis 22 a is used as the optical reference axis S of the inspection optical unit 20. The illumination optical axis 21a, the photographing optical axis 22a, and the optical reference axis S are arranged in the same plane. Therefore, the focal point F and the reference point 30 exist on the optical reference axis S. The reference point 30 is located in front of the focal point F. The separation distance between the reference point 30 and the focal point F corresponds to the general radius of curvature R of the cornea of the eye E (see FIG. 6B). When the focal point F is aligned with the cornea of the eye E, the position of the reference point 30 in the apparatus 1 substantially coincides with the curvature center Q of the cornea of the eye E. Accordingly, in this state, when the inspection optical unit 20 is rotated about the reference point 30 about the X axis and the Y axis, the focal point F moves in an arc along the cornea surface of the eye E to be examined. It will be.

[Description of configuration of each optical system]
The illumination optical system 21 includes an illumination light source 31 for photographing composed of LEDs that illuminate the anterior segment of the eye E. Visible light from the illumination light source 31 passes through the condenser lens 32 and the imaging slit member 33. The slit light that has passed through the photographing slit member 33 is converged on the anterior eye portion of the eye E by passing through the illumination objective lens 34. In the present embodiment, a mirror 35 for changing the direction of the illumination optical axis 21a is provided.

  The cornea photographing optical system 22 has a photographing CCD 36 for photographing corneal cells. The slit light reflected by the cornea of the eye E is transmitted through the photographing objective lens 37, the field stop 38, and the relay lens 39 and guided to the photographing CCD 36. In the present embodiment, mirrors 40 and 41 for changing the direction of the photographing optical axis 22a are provided. The field stop 38 is disposed at the first imaging point of the eye E. The illumination optical system 21 and the cornea photographing optical system 22 also have detailed alignment and focusing functions. These functions will be described later.

  The alignment index projection optical system 24 has a light source 42 for alignment index light composed of infrared LEDs. Near-infrared light from the alignment light source 42 passes through the projection lens 43 to be collimated, and is irradiated onto the anterior eye portion from the front thereof. In the present embodiment, a mirror 44 for changing the direction of the alignment optical axis 24a is provided. On the alignment optical axis 24a, a visible light reflecting infrared light transmission mirror 45 is provided to make the alignment optical axis 24a coaxial with an optical axis 25a of a fixation target optical system 25 described later. Further, on the alignment optical axis 24a, a half mirror 46 is provided for synthesizing coaxially with an optical axis 23a of the anterior ocular segment observation optical system 23 described later. The optical axis 23a of the anterior ocular segment observation optical system 23 coaxial with the alignment optical axis 24a bisects the angle formed by the illumination optical axis 21a and the photographing optical axis 22a. In other words, the optical axis 23 a of the anterior ocular segment observation optical system 23 coincides with the optical reference axis S.

  The anterior ocular segment observation optical system 23 has a CCD 47 for anterior ocular segment observation. Near infrared light from the alignment light source 42 is reflected by the eye E to be examined. A bright spot (also referred to as a Purkinje image) as a reflected image is transmitted through the anterior segment imaging lens 48 and received by the CCD 47. The CCD 47 that images the anterior segment has a much lower imaging magnification than the CCD 36 that images corneal endothelial cells. A visible light cut filter 49 is provided in front of the CCD 47.

  Alignment is performed based on the Purkinje image received by the CCD 47. Specifically, it is as follows. First, the inspection optical unit 20 is advanced toward the eye E along the Z axis by the XYZ table 2. At this point, the Z axis coincides with the optical reference axis S. When the Purkinje image can be detected by the anterior ocular segment observation optical system 23, the inspection optical unit 20 is moved in the XY directions for alignment. On the display unit 19, the anterior segment image captured by the anterior segment observation optical system 23 is displayed together with the Purkinje image at the corneal vertex T position. The XYZ table 2 is moved in the XY axis direction so that the Purkinje image reaches a predetermined position on the display screen of the CCD 47, for example, the screen center position corresponding to the optical reference axis S. Thereby, the optical reference axis S is made to coincide with the corneal apex T of the eye E to be examined. This alignment is referred to as an alignment operation. Further, as will be described later, this is called reference alignment.

  The fixation target optical system 25 includes a fixation lamp 50 and a mask 51 made of visible light LEDs. A small hole 51 a having a predetermined shape is formed in the mask 51. The fixed index light having a predetermined shape that has passed through the small hole 51a from the fixation lamp 50 is reflected by the visible light reflection infrared light transmission mirror 45, and is irradiated to the eye E along the alignment optical axis 24a. . The direction of the eye E is fixed when the subject stares at the fixation index light.

  This device 1 is a device that does not require changing the orientation of the eye E when photographing a plurality of different parts of the anterior segment. The subject only needs to face forward naturally with the face fixed to the forehead pad 52 and the liftable chin rest 53. By moving the inspection optical unit 20, a plurality of different parts of the cornea of the eye E can be imaged. However, the front vision state of the eye E may be fixed using the fixation target optical system 25. The fixation lamp 50 is not intended to change the direction of the eye E, but is provided so that the subject can easily fix the line of sight in one direction.

  The control unit 15 includes a test position specifying unit 15a and a normal direction calculation unit 15b. The operation will be described with reference to FIG. 6A is a front view showing the anterior segment of the eye E, the corneal apex T, and the designated imaging region (designated region to be examined) M, and FIG. 6B is along the VI-VI line. FIG. The test position specifying unit 15a is operated by clicking the mouse of the operation unit 18 or the like, and a desired site on the anterior segment image displayed on the display unit 19 is specified as the test site. The position of the designated part M in the plane coordinates or the circular coordinates is specified (FIG. 6A). The origin of the coordinates in this case is, for example, the corneal apex T on the anterior ocular segment image viewed in the direction facing the line of sight of the eye E to be examined.

  Generally, the curvature radius of the corneal epithelium of the human eye is about 7.7 mm, and this is R. According to the normal direction calculation unit 15b, from the curvature radius R and the distance D between the position of the corneal apex T on the anterior segment image and the specified test site M, the specified test site is geometrically specified. The three-dimensional position of M and the direction of the normal N at the designated test site M are calculated (FIG. 6B). For example, it is assumed that the designated test site M is a point separated from the corneal apex T position in the anterior segment image by a distance D upward in the Y-axis direction, and the corneal curvature radius is R. The direction of the normal N in this case is a direction that forms an angle of θy2 = arcsin (D / R) upward with respect to the horizontal optical reference axis S passing through the pupil center 58.

Below, operation | movement of the apparatus 1 for imaging | photography the arbitrary points on the cornea of the eye E to be examined is demonstrated.
[Standard alignment]
As shown in FIG. 1, first, the face of the subject is applied to the forehead rest 52 installed at the upper front of the apparatus 1 at the standby position and the elevating chin rest 53 installed at the lower front. Fix the face direction by touching. The anterior segment LED 26 at the front of the main body 10 is lit to illuminate the anterior segment. Next, the height of the elevating chin rest 53 and the left and right positions of the head are approximately matched so that the anterior segment image is included in the imaging screen of the CCD 47 of the anterior segment observation optical system 23. A captured image of the anterior segment is displayed on the display unit 19. The direction of the eye E is fixed by causing the subject to fixate the fixation index light from the fixation lamp 50. In this state, an imaging button (start button) (not shown) of the apparatus 1 is pressed, and the inspection optical unit 20 advances in the Z-axis direction toward the eye E by driving the XYZ table 2.

  When the Purkinje image P is detected on the anterior segment image received by the CCD 47, the advancement of the inspection optical unit 20 stops. Next, the inspection optical unit 20 is displaced in the XY directions so that the Purkinje image P is positioned within a predetermined range at the center of the anterior segment image, for example. Thereby, the optical reference axis S is made to coincide with the corneal apex T corresponding to the pupil center of the eye E to be examined. This alignment is referred to as an alignment operation. Since this alignment is not for the designated test site M, it is called preliminary alignment or reference alignment.

[Confirmation of the angle between the visual axis of the eye E and the eye axis]
FIG. 7 shows a cross-sectional plan view of the eye E in a state in which the reference alignment has been performed, and an anterior eye image 60 of the eye E observed by the anterior eye observation optical system 23. As shown in FIG. 7A, the visual axis 56 is generally assumed to be displaced inward from the eye axis 57 by about 5 ° to 7 °. This is because the fovea (macular center), which is a fixation corresponding point on the retina, is shifted from the eye axis to the ear side. In addition, since eye characteristics peculiar to the subject such as convergence, some perspective, and a non-circular pupil are added, the relationship between the visual axis 56 and the eye axis 57 is not uniform. FIG. 7A illustrates an eye E to be examined in which the visual axis 56 and the eye axis 57 are shifted by a predetermined angle θx1 in the X-axis direction. In FIG. 7A, for easy understanding, the deviation between the visual axis 56 and the eye axis 57 is shown to be considerably larger than actual. FIG. 7B illustrates the eye E to be examined in which the visual axis 56 and the eye axis 57 coincide. Here, the visual axis 56 is a straight line connecting the target object to be watched and the fovea of the fundus of the eyeball. The eye axis 57 is a straight line that passes through the pupil center 58 and connects the anterior and posterior poles of the eyeball. If the visual axis 56 and the eye axis 57 are misaligned, the Purkinje image P on the anterior segment image 60 is separated from the pupil center 58 even if the reference alignment is performed. In the example of FIG. 7A, the Purkinje image P is separated from the pupil center 58 by a distance d in the X-axis direction. Reference numeral 59 in the figure indicates an iris, and reference numeral 61 indicates a rotation point of the eye E to be examined. The rotation point 61 is a center point of rotation when the eyeball changes the direction of the eye axis 57.

In a state where the reference alignment with respect to the eye E is performed, the angle θx1 formed by the eye axis 57 and the visual axis 56 is confirmed. The deviation angle θx1 is the distance d between the Purkinje image P and the pupil center 58, the curvature radius R of the cornea of the eye E, and the distance in the Z-axis direction between the position of the Purkinje image P and the corneal apex T. From L, the following formula is used.
θx1 = arctan (d / (RL))
The separation distance d can be read from the anterior segment image 60. As the curvature radius R and the separation distance L of the cornea, an average value of each value for a general human eye may be used. In this case, R = 3.8 mm and L = 7.7 mm. In the eye E shown in FIG. 7B, d = 0, and the deviation angle θx1 = 0. In this case, the Purkinje image P coincides with the pupil center 58 on the anterior segment image 60.

  FIG. 7A illustrates a state in which the eye axis 57 is inclined only in the X-axis direction from the visual axis 56 in a state where the reference alignment is performed. However, it may be inclined only in the Y-axis direction or in the middle direction between the X-axis direction and the Y-axis direction. In these cases, the deviation angle θx1 in the X-axis direction and the deviation angle θy1 in the Y-axis direction are calculated.

[Specifying the test site and calculating the turning angle of the eye E]
In the following description of the operation procedure of the apparatus 1, the eye E of FIG. 7B in which the visual axis 56 and the eye axis 57 coincide is assumed for easy understanding. As described above with reference to FIG. 6, the test site is specified by the operator operating the operation unit 18, so that any site on the anterior eye image 60 can be detected via the test position designating unit 15 a. Designated as test site M. An anterior eye image 60 in which the test site M is designated is recorded in the control unit 15.

  FIG. 8 shows a case where a site different from the example of FIG. 6 is designated as the test site. FIG. 8A shows a plan view cross-sectional view of the eye E and an anterior eye image 60 at the time of reference alignment before turning of the main body 10 (inspection optical unit 20). FIG. 8B shows a cross-sectional plan view of the eye E and the anterior eye image 60 after the test optical unit 20 is turned. In FIG. 8A, the Purkinje image P appears at the pupil center 58 in the anterior segment image 60. Here, a position separated from the pupil center 58 in the anterior segment image 60 by a predetermined distance X2 in the X-axis direction is designated as the test site M. The direction of the normal N of the designated part is calculated by the normal direction calculation unit 15b as described above. The normal direction calculation unit 15b calculates an angle formed by the visual axis 56 (matching with the optical reference axis S) of the eye E to be inspected at the time of reference alignment and the normal N and the direction thereof. The normal direction calculation unit 15b calculates this angle from the separation distance X2 and the curvature radius R of the cornea. In this example, this angle is θx2 = arcsin (X2 / R) in the X-axis direction. This angle θx2 and direction (X-axis direction) correspond to the angle and direction that the inspection optical unit 20 should turn. Here, the X-axis direction is taken as an example of the direction in which the inspection optical unit 20 should turn, but of course it is not limited to the X-axis direction. There are cases in the Y-axis direction and in the middle direction between the X-axis and the Y-axis. When the above-described deviation angle (θy or the like) exists in the eye E, this added to the above θx2 is the angle to turn. The angle and direction in which the inspection optical unit 20 should turn is recorded in the control unit 15.

[Swivel movement of inspection optical unit 20]
The normal direction calculation unit 15b transmits the angle θx2 and the direction to be turned, which are the calculation results, to the main body drive unit 16 as control information. Based on this information, the main body drive unit 16 turns the inspection optical unit 20 by a predetermined angle θx2 in the X-axis direction, and the vertical rotation drive device 13 of the vertical rotation drive mechanism 11 and the horizontal rotation drive mechanism. 12 left-right rotation drive devices 14 are driven. By this turning drive, the optical reference axis S substantially coincides with the direction of the normal line N. At least the optical reference axis S is substantially parallel to the normal line N. In the anterior ocular segment image 60 after the pivoting movement displayed on the display unit 19, the Purkinje image P appears at the position of the designated test site M (FIG. 8B). This anterior segment image 60 is recorded in the control unit 15. It should be noted that the angle and direction in which the inspection optical unit 20 actually turns can be easily calculated and confirmed from the anterior segment image 60. This actually swiveled angle and direction can be compared with the angle and direction that the inspection optical unit 20 should turn. Based on this comparison, it is possible to determine whether or not the eye E has been displaced while the inspection optical unit 20 is turning. Further, even if there is no fixation lamp 50 for fixing the eye E to the front view state, the angle θx2 and the direction can be used assuming the front view state of the eye E to be examined.

  The anterior eye image 60 after the rotation of the inspection optical unit 20 is an image obtained by viewing the eye E from the normal N direction. However, as shown in FIG. 9, this Purkinje image P is not a reflection image at the corneal endothelium 63 to be imaged but a reflection image at the corneal epithelium 62. The optical reference axis S is not aligned with the corneal endothelium 63 but with the apex T of the corneal epithelium 62.

  FIG. 9A shows the optical path in the eye E during reference alignment, and FIG. 9B shows the optical path in the eye E after the inspection optical unit 20 is turned. As shown in FIG. 9, the radius of curvature Ru of the corneal epithelium 62 is larger than the radius of curvature Ri of the corneal endothelium 63. In FIG. 9, for easy understanding, the difference between the radius of curvature Ru of the corneal epithelium 62 and the radius of curvature Ri of the corneal endothelium 63 is shown to be much larger than the actual cornea. At the time of the reference alignment shown in FIG. 9A, the rotation point 61 of the eyeball, the center of curvature Qu of the corneal epithelium 62, the center of curvature Qi of the corneal endothelium 63, and the pupil center 58 are all on the eye axis 57 of the eyeball. . These points 61, Qu, Qi, and 58 are all on a straight line. The center of curvature Qu of the corneal epithelium 62 is located in front of the center of curvature Qi of the corneal endothelium 63, that is, on the back side of the eye E to be examined. In FIG. 9, for easy understanding, the distance between the center of curvature Qu of the corneal epithelium 62 and the center of curvature Qi of the corneal endothelium 63 is also much larger than the actual cornea. Thus, the cornea has a meniscus concave lens shape. Accordingly, as shown in FIG. 9A, the Purkinje image P is formed on the eye axis 57 in a state where the reference alignment is performed so that the optical reference axis S coincides with the eye axis 57 of the eye E to be examined. In this state, the optical reference axis S is orthogonal to the apex T of the corneal epithelium 62 and is also orthogonal to the apex Ti of the corneal endothelium 63. It is considered that a clear photographed image of endothelial cells can be obtained by photographing in this state.

  However, as shown in FIG. 9B, after the inspection optical unit 20 is turned, the imaging position of the Purkinje image P deviates from the eye axis 57. In the alignment method in which the optical reference axis S is aligned with the Purkinje image P, the optical reference axis S is orthogonal to the vertex T of the corneal epithelium 62 but not orthogonal to the vertex Ti of the corneal endothelium 63. This is because the cornea has a meniscus concave lens shape as described above. It is considered that a clear photographed image of endothelial cells cannot be obtained when photographed in this state. Therefore, as described below, detailed alignment that is not based on the Purkinje image P in the corneal epithelium 62 is required.

[Detailed alignment and focusing after turning of inspection optical unit 20]
After the inspection optical unit 20 turns, the control unit 15 controls the inspection optical unit 20 from movement in the XYZ orthogonal triaxial direction to movement of the ABC substantially in the orthogonal triaxial direction through the polar coordinate transformation. Is converted to In this detailed alignment, “focus”, which is alignment in the C-axis direction, which is the approaching direction (reference optical axis direction S) to the eye E, is also performed. The C axis is the optical reference axis S after the inspection optical unit 20 is turned. The C-axis extends in a direction inclined by the turning angle θx2 with respect to the Z-axis at the time of reference alignment. The A axis is an axis that is perpendicular to the C axis and extends in the horizontal direction. The B axis is an axis in a direction perpendicular to the A axis and the C axis.

  In order to obtain a clear endothelial cell image, it is preferable to move the inspection optical unit 20 in the A-axis direction and the B-axis direction so that the optical reference axis S substantially coincides with the designated test site Mi of the endothelium. It is done. In the present embodiment, as will be described later, detailed alignment is performed based on the luminance information of the corneal endothelium image 65. Along with this detailed alignment, as the focusing operation, the inspection optical unit 20 is moved in the C-axis direction so that the focal point F of the inspection optical unit 20 coincides with the inner skin. The detailed alignment operation and the focusing operation are performed simultaneously. As described above, in FIG. 9, the difference between the radius of curvature Ru of the corneal epithelium 62 and the radius of curvature Ri of the corneal endothelium 63 and the separation distance between the center of curvature Qu of the corneal epithelium 62 and the center of curvature Qi of the corneal endothelium 63 are as follows. It is much larger than the actual cornea. Therefore, in FIG. 9, the position Mu where the optical reference axis S at the same inclination angle is orthogonal to the corneal epithelium 62 and the position Mi orthogonal to the corneal epithelium 62 are greatly separated. However, in the actual human eye, the distance between the positions Mu and Mi in the AB plane is extremely small. This separation distance is about 0.2 mm when the turning angle is 30 °. If the turning angle is reduced, the separation distance is also reduced.

  The movement of the inspection optical unit 20 in the respective axis directions of ABC is performed by the XYZ table 2 even after turning. For this reason, in the control unit 15, control axis conversion (coordinate axis conversion) from each axis of XYZ to each axis of ABC is generally performed as follows. The three orthogonal axes after the optical reference axis S turns by θx and θy from the reference alignment position are defined as three axes of ABC. In the control unit 15, a velocity vector in a certain direction in the ABC triaxial coordinate system is converted into a velocity vector in the XYZ coordinate system of the XYZ table 2. The velocity vector in the ABC triaxial coordinate system represents the movement for detailed alignment and focusing. First, this velocity vector is defined by fr, fθy, and fθx in the polar coordinate system as shown in the following formula. The velocity vector in the polar coordinate system is converted into fx, fz, and fy in the XYZ coordinate system of the XYZ table 2 that is an actual drive system. This conversion is performed by the following equation.

  The corneal imaging optical system 22 determines whether the focal point F of the inspection optical unit 20 matches the designated test site Mi of the endothelium in each ABC axis direction, that is, whether the detailed alignment and focusing have been performed. This is automatically performed based on the luminance distribution of the obtained corneal endothelium image 65 (see FIGS. 11 and 12) and the position of the corneal endothelium image 65 on the screen. When it is determined that detailed alignment and focusing have been performed, the corneal endothelium image 65 is automatically captured and recorded. The corneal endothelium image 65 is taken by the photographing CCD 36 of the cornea photographing optical system 22 described above. The above-described reference alignment is performed based on the anterior segment image 60 by the CCD 47 of the anterior segment observation optical system 23 having a small photographing magnification. However, the CCD 36 for corneal imaging has a higher imaging magnification than the CCD 47 of the anterior ocular segment observation optical system 23. For this reason, in the detailed alignment and focusing operations, the movement distance and movement speed of the inspection optical unit 20 are both small, and the movement control by the control unit 15 is very precise.

[Focus operation after turning of inspection optical unit 20]
As an example of a criterion for determining that focusing has been performed among the detailed alignment and focusing, the corneal endothelium image 65 is determined as being in a predetermined position on the image receiving surface of the imaging CCD 36. The predetermined position is a position where the corneal endothelial cell can be most clearly imaged. When the intersection (focusing point) F between the illumination optical axis 21a and the imaging optical axis 22a moves on the C axis and reaches the imaging target site of the corneal endothelium, the image processing unit 17 detects the in-focus. At this time, on the condition that the detailed alignment has been achieved, the CCD 36 can clearly photograph the region to be imaged (corneal endothelial cell).

  FIG. 10 relatively shows a state in which the inspection optical unit 20 approaches the cornea of the eye E fixed in the C-axis direction for focusing. In FIG. 10, for the sake of easy understanding, the inspection optical unit 20 is fixed and the cornea 55 is approaching the inspection optical unit 20. The standby position of the apparatus 1 is a position where the inspection optical unit 20 is sufficiently separated from the eye E and cannot be focused. FIG. 10 also shows the movement of the slit image accompanying the movement of the inspection optical unit 20 in the C-axis direction. That is, a slit image moving on the screen 36a of the photographing CCD 36 is shown. The slit image is received by the photographing CCD 36. The image on the screen 36 a is processed by the image processing unit 17 and sent to the control unit 15. This image can also be displayed on the display unit 19 by the operation of the operation unit 18. The slit images shown in FIG. 10 are a corneal epithelial image 64 and a corneal endothelium image 65. An image by the slit light reflected by the corneal epithelium 62 is a corneal epithelial image 64, and an image by the slit light reflected by the corneal endothelium 63 is a corneal endothelium image 65. The corneal endothelium image 65 has less light than the corneal epithelial image 64. The imaging target is a corneal endothelium image 65.

  As shown in FIG. 10, as the inspection optical unit 20 approaches the eye E (the cornea 55 approaches the inspection optical unit 20), the position received through the imaging objective lens 21 is indicated by an arrow in the figure. Move in direction A. The corneal epithelium image 64 and the corneal endothelium image 65 move in the direction of arrow A in that order. In FIG. 10, the first optical axis 22a1 is the optical axis of the reflected image on the corneal epithelium 62 of the examination optical unit 20 before the approaching movement. The second optical axis 22a2 is an optical axis of a reflected image on the corneal endothelium 63 of the inspection optical unit 20 after moving close to a predetermined distance. The third optical axis 22a3 is an optical axis of a reflected image on the corneal epithelium 62 of the inspection optical unit 20 after moving close to a predetermined distance. The corneal endothelium image 65 to be imaged is imaged on the condition that detailed alignment has been achieved when it is correctly positioned at a predetermined position on the screen 36a of the CCD 36.

[Detailed alignment operation after turning of inspection optical unit 20]
An example of determining that the detailed alignment has been made will be described with reference to FIG. Further, another example of the determination will be described with reference to FIG. A corneal endothelium image 65 is shown in FIGS. Actually, this figure is a photograph of the artificial artificial eye endothelium, but there is no problem in explaining the luminance information of the corneal endothelium image 65 described later. Since the illumination light applied to the eye E from the illumination light source 31 is slit light, the corneal endothelium image 65 received by the CCD 36 is a slit-shaped image. As an example of a criterion for determining that the detailed alignment has been performed, the luminance distribution of the corneal endothelium image 65 is substantially uniform, the luminance of the upper and lower portions of the corneal endothelium image 65 is substantially equal, and the luminance of the left and right portions. Are determined to be substantially equal. This luminance distribution includes the luminance itself and its distribution.

  FIG. 11 shows five corneal endothelium images 65 from (a) to (e). A corneal endothelium image 65 of FIG. 11A arranged at the center of FIG. 11 shows a state in which it is determined that the luminance distribution is substantially uniform and the detailed alignment is substantially achieved. A corneal endothelium image 65 in FIG. 11B on the left side shows an image of a portion shifted by about 0.5 mm from the corneal endothelium portion in FIG. The corneal endothelium image 65 in FIG. 11 (c) on the right side shows an image of a portion displaced by about 0.5 mm from the corneal endothelium portion in FIG. The upper corneal endothelium image 65 in FIG. 11 (d) shows an image of a portion shifted by about 0.5 mm from the corneal endothelium portion in FIG. The upper corneal endothelium image 65 in FIG. 11 (e) shows an image of a portion shifted by about 0.5 mm from the corneal endothelium portion in FIG. As shown in the drawing, luminance measurement lines indicating the measurement target portions of the corneal endothelium image 65 are arranged at two upper and lower portions so as to extend in the left-right direction. This luminance measurement line is referred to as a horizontal luminance measurement line BLH.

  FIG. 12 also shows five corneal endothelium images 65 from (a) to (e). The corneal endothelium image 65 in FIG. 12 is the same as the corneal endothelium image 65 in FIG. The corneal endothelium image 65 of FIG. 12A arranged at the center of FIG. 12 shows a state in which it is determined that the luminance distribution is substantially uniform and the detailed alignment is substantially achieved. A corneal endothelium image 65 in FIG. 12B on the left side shows an image of a portion shifted by about 0.5 mm from the corneal endothelium portion in FIG. The corneal endothelium image 65 in FIG. 12C on the right side shows an image of a portion that is shifted by about 0.5 mm from the corneal endothelium portion in FIG. The upper corneal endothelium image 65 in FIG. 12 (d) shows an image of a portion shifted by about 0.5 mm from the corneal endothelium portion in FIG. The upper corneal endothelium image 65 in FIG. 12 (e) shows an image of a portion shifted about 0.5 mm from the corneal endothelium portion in FIG. In FIG. 12, luminance measurement lines are arranged at two positions on the left and right sides of the corneal endothelium image 65 so as to extend in the vertical direction. This luminance measurement line is referred to as a vertical luminance measurement line BLV.

  In FIG. 11B and FIG. 11C exemplifying a state where the center of the corneal endothelium in FIG. 11A is shifted to the left and right by about 0.5 mm, the horizontal luminance measurement line BLH is illustrated. The luminance distribution is not uniform. In FIGS. 11D and 11E exemplifying a state where the center of the corneal endothelium in FIG. 11A is shifted up and down by about 0.5 mm, the luminance distribution on the upper and lower horizontal luminance measurement lines BLH is illustrated. And the average luminance (which may be an integral value of luminance) are different from each other. Thus, by providing the two upper and lower horizontal luminance measurement lines BLH, it is possible to detect the luminance distribution of the corneal endothelium image 65 and determine whether or not the detailed alignment is substantially achieved.

  In FIG. 12B and FIG. 12C exemplifying a state where the center of the corneal endothelium in FIG. 12A is shifted to the left and right by about 0.5 mm, the left and right vertical luminance measurement lines BLV are illustrated. The upper luminance distribution and the average luminance (which may be an integrated luminance value) are different from each other. In FIG. 12 (d) and FIG. 12 (e) exemplifying the state where the center of the corneal endothelium in FIG. 12 (a) is shifted up and down about 0.5 mm, the luminance distribution on the vertical luminance measurement line BLV is uniform. is not. As described above, by providing the left and right vertical luminance measurement lines BLV, it is possible to detect the luminance distribution of the corneal endothelium image 65 and determine whether or not the detailed alignment is substantially achieved.

  The present invention is not limited to the above, and two horizontal luminance measurement lines BLH and two vertical luminance measurement lines BLV may be provided. Further, even if one horizontal luminance measurement line BLH and one vertical luminance measurement line BLV are provided, the luminance distribution of the corneal endothelium image 65 is detected and the detailed alignment is substantially achieved as described above. It becomes possible to judge whether. In short, any configuration that can discriminate the luminance distribution in the vertical and horizontal directions of the obtained slit-like endothelium image may be used.

  During the detailed alignment operation, the control unit 15 transmits luminance information on the vertical luminance measurement line BLV and / or the horizontal luminance measurement line BLH from the image processing unit 17 to the main body driving unit 16. The main body drive unit 16 drives the XYZ table 2 so as to move the inspection optical unit 20 in a direction in which the luminance distributions on the upper and lower horizontal luminance measurement lines BLH approach each other. Alternatively, the XYZ table 2 is driven so that the inspection optical unit 20 is moved in a direction in which the luminance distribution on each horizontal luminance measurement line BLH is uniformized. Alternatively, the XYZ table 2 is driven so that the inspection optical unit 20 is moved in a direction in which the average luminances (which may be integrated luminance values) on the upper and lower horizontal luminance measurement lines BLH approach each other. Alternatively, the main body driving unit 16 drives the XYZ table 2 so as to move the inspection optical unit 20 in a direction in which the luminance distributions on the left and right vertical luminance measurement lines BLV approach each other. Alternatively, the main body drive unit 16 drives the XYZ table 2 so as to move the inspection optical unit 20 in a direction in which the luminance distribution on the vertical luminance measurement line BLV is uniform. Alternatively, the main body driving unit 16 drives the XYZ table 2 so that the inspection optical unit 20 is moved in a direction in which the average luminance (which may be an integrated value of luminance) on the left and right vertical luminance measurement lines BLV approaches each other. Alternatively, the XYZ table 2 is driven so that the inspection optical unit 20 is moved based on a combination of at least two types of the luminance information. That is, the inspection optical unit 20 is moved in both the AB axis directions in which the luminance distribution of the corneal endothelium image 65 is substantially uniform.

  Instead of the luminance measurement lines BLV and BLH, a range to be a luminance measurement target (not shown) may be provided at each of the four corners of the corneal endothelium image 65 having a rectangular slit shape. In this case, the main body drive unit 16 drives the XYZ table 2 so as to move the inspection optical unit 20 in a direction in which the average luminance (which may be an integrated value of luminance) of the four luminance measurement regions is substantially the same. You may do it.

  As shown in FIGS. 11 and 12, the rectangular slit-shaped corneal endothelium image 65 has a narrow width in the vertical direction (B-axis direction) and a wide width in the horizontal direction (A-axis direction). When the inspection optical unit 20 is displaced in the horizontal direction (long side direction), a luminance change is likely to appear at both ends in the horizontal direction of the image 64 as compared to when the inspection optical unit 20 is displaced in the vertical direction (short side direction). With the displacement in the horizontal direction (long side direction), even if the amount of displacement is small, luminance changes tend to appear at both ends of the image 64, but with a small amount of displacement in the vertical direction (short side direction), both ends of the image 64 Changes in brightness are unlikely to appear. Therefore, the main body drive unit 16 is relatively slow in the long side direction (A-axis direction) and relatively fast in the short side direction (B-axis direction) until a change in luminance appears in the initial operation of detailed alignment. The XYZ table 2 may be driven so as to move the inspection optical unit 20.

  FIG. 13 shows an optical path diagram of another corneal examination apparatus (hereinafter also simply referred to as an apparatus) 71. The apparatus 71 is different from the apparatus 1 of FIG. 5 in that the alignment index projection optical system 73 in the inspection optical unit 72 is not provided with a dedicated receiver, and the imaging CCD 36 of the cornea imaging optical system 22 receives the image for alignment. It also functions as a vessel. As a result, the mirror 41 in the apparatus 1 of FIG. 5 is replaced with a visible light reflecting infrared light transmitting mirror 74. As for other devices, both devices 1 and 71 are the same. Therefore, in FIG. 13, the same reference numerals are given to the same devices as the constituent members of the apparatus 1 of FIG. 5, and the description thereof is omitted.

  In this apparatus 71, both the corneal endothelium image 65 by the corneal imaging optical system 22 and the anterior segment image by the anterior segment observation optical system 23 are captured by the common imaging CCD 36. The imaging of the corneal endothelium 63 and the imaging of the anterior segment are performed by the same CCD 36, although the imaging magnification differs greatly. The corneal endothelium image 65 and the anterior ocular segment image have different imaging timings so that the corneal endothelium image 65 and the anterior ocular segment image are not captured in an overlapping state. The illumination light source 31 of the illumination optical system 21 and the alignment light source 42 of the alignment index projection optical system 24 are blinked in synchronization with the photographing cycle of the photographing CCD 36. The illumination light source 31 and the alignment light source 42 are turned on alternately. Therefore, the corneal endothelium image 65 and the anterior ocular segment image are not superimposed and are obtained as different images.

  According to the corneal examination apparatus of the present invention, even when examining a plurality of different parts of the eye to be examined, it is not necessary to change the line-of-sight direction while the eye to be examined is fixed. Therefore, it is useful for the examination of the peripheral part of the cornea in the anterior segment.

DESCRIPTION OF SYMBOLS 1,71 Corneal inspection apparatus 2 XYZ table 3 Support frame 4 X table 5 Y table 6 Z table 7 Guide groove 8 Guided member 9a Rack 9b Pinion gear 10 Main body 11 Vertical rotation drive mechanism 12 Left-right rotation drive mechanism 13 Vertical rotation Drive device 14 Left-right rotation drive device 15 Control unit 16 Main body drive unit 17 Image processing unit 18 Operation unit 19 Display unit 20, 72 Inspection optical unit 21 Illumination optical system 22 Imaging optical system 23 Anterior eye observation optical system 24, 73 Alignment index Projection optical system 25 Fixation target optical system 30 Reference point 31 Photographing illumination light source 32 Condenser lens 33 Photographing slit member 34 Illumination objective lens 35, 40, 41, 44 Mirror 36 Photographing CCD
37 Objective lens (condensing lens)
38 Field stop 39 Relay lens 42 Light source for alignment 43 Projection lens 45, 74 Visible light reflecting infrared light transmitting mirror (cold mirror)
46 Half mirror 47 CCD for anterior segment observation
48 Anterior imaging lens 49 Visible light cut filter 50 Fixation lamp (LED)
51 Mask 52 Forehead 53 Elevating chin rest 55 Cornea 56 Visual axis 57 Eye axis 58 Pupil center 59 Iris 60 Anterior eye image 61 Rotation point 62 Epithelium 63 Endothelium 64 Corneal epithelial image 65 Corneal endothelium image BLH Transverse luminance measurement line BLV Vertical Luminance measurement line d Separation distance between Purkinje image (in the anterior segment) and pupil center E Subject eye F Focus point L Separation between Purkinje image imaging position (on the eye axis) and apex of cornea M Designated test site ( (Examination site)
N (normal at specified test site) P Purkinje image Q Center of curvature of cornea R Radius of curvature of cornea S Optical reference axis T Top of cornea

Claims (5)

An inspection optical unit having an anterior ocular segment observation optical system and a cornea photographing optical system;
A linear drive mechanism for linearly moving the inspection optical unit;
A turning drive mechanism for turning and moving the inspection optical unit;
A control unit for controlling the movement drive of the inspection optical unit by the linear drive mechanism and the turning drive mechanism in order to align the inspection optical unit with a designated position of the eye to be examined; and
The control unit includes a test position specifying unit that specifies a test site on the anterior segment image, and a normal direction calculation unit that calculates the normal of the specified test site,
Control by this control unit
Control of the drive by the linear drive mechanism and the turning drive mechanism in order to align the optical reference axis of the inspection optical unit with the normal line in the designated test site;
Control of driving by a linear drive mechanism for aligning and focusing the inspection optical unit with respect to the designated test site of the corneal endothelium based on the luminance information of the corneal endothelium image obtained by the corneal imaging optical system. And a corneal examination apparatus. The linear drive mechanism moves the inspection optical unit in three orthogonal XYZ directions including the Z axis that coincides with the optical reference axis.
The control unit is configured so that the inspection optical unit after turning so that the optical reference axis is along the normal direction can move in an orthogonal three-axis direction of ABC including the C axis that coincides with the optical reference axis. The cornea examination device according to claim 1 which controls a drive of a linear drive mechanism.   The said control part WHEREIN: The velocity vector of the orthogonal triaxial direction of the said ABC is defined by a polar coordinate, The velocity vector of this polar coordinate is converted into the said XYZ orthogonal triaxial velocity vector. Corneal examination device. The luminance information of the corneal endothelium image includes the luminance distribution of the corneal endothelium image obtained by the corneal imaging optical system,
The control unit controls driving of the linear drive mechanism to move the inspection optical unit in a direction in which the luminance distribution becomes uniform based on a change in luminance distribution of the corneal endothelium image accompanying movement of the inspection optical unit. The corneal examination apparatus according to any one of claims 1 to 3.   The control unit determines at least one of the luminance of the vertical luminance measurement target portions near the left and right ends of the corneal endothelium image and the luminance of the horizontal luminance measurement target portions of the corneal endothelium images near the upper and lower end portions. 5. The cornea inspection device according to claim 4, wherein an alignment based on uniformity of the luminance distribution is determined by measuring and comparing the luminance.