JP4495292B2 - Corneal cell imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a corneal cell imaging apparatus. More specifically, the present invention relates to a corneal cell photographing apparatus for observing and photographing corneal cells without making contact with an eye to be examined by a specular method. A specular imaging apparatus is an apparatus that irradiates illumination light obliquely with respect to the optical axis of an eye to be examined, receives specularly reflected light from the cornea obliquely, and observes and captures this image.
[0002]
[Prior art]
Conventionally, an apparatus for clearly observing and photographing corneal epithelial cells has not been known. In past contact-type imaging devices, an image of the surface layer (mucin layer or tear film) formed on the surface of the corneal epithelium is mixed in order to image by contacting a cone lens as an objective lens against the eye to be examined, In addition, these layers are photographed in a damaged or destroyed state. As a result, as-is epithelial cells cannot be photographed.
[0003]
Further, in the non-contact type imaging device, the reflected light from the epithelial cells out of the reflected light of the illumination light irradiated on the surface of the eye to be examined cannot be separated from the reflected light from the surface layer, and thus the epithelial cells are imaged. I can't. The reason why the reflected light from the surface layer and the reflected light from the epithelial cells cannot be separated is as follows.
[0004]
FIG. 6 is a view showing a cross section of the cornea C in the vicinity of the epithelium U. FIG. The layer of the epithelium U has a thickness of about 50 microns, and the surface layer S on the surface side thereof has an average thickness of 10 microns or less including the mucin layer and the tear film as a sebum layer. Therefore, when the slit-shaped illumination light L for observation and photographing is irradiated to the anterior eye portion of the eye to be examined from the oblique front, the reflected light Ru from the epithelial cells and the reflected light Rs from the surface layer S overlap in the most range. End up. If the width of the slit light is reduced, the amount of light is insufficient, and the width of the photographing range is reduced. In the figure, reference numeral I denotes the endothelium, and reference numeral J denotes the corneal stroma.
[0005]
The present invention has been made to solve such a problem, and effectively separates the reflected light from the epithelial cells while being non-contact with the eye to be examined, so that a clear epithelial cell image can be obtained with a sufficient amount of illumination light. An object of the present invention is to provide a corneal cell imaging apparatus that can be obtained.
[0006]
[Means for Solving the Problems]
The corneal cell imaging apparatus of the present invention comprises:
An illuminating optical system for illuminating the anterior eye portion of the eye to be examined from the diagonally front by the slit illumination light passing through the first slit, and a movable second slit And an imaging optical system for imaging the reflected light reflected by the anterior segment of the slit illumination light through a second slit, and the second slit is configured to transmit the reflected light accompanying the movement of the first slit. It is configured to move in synchronization with the moving direction.
[0007]
Therefore, the slit illumination light moves on the cornea of the eye to be examined, and the moving reflected light can be observed and photographed. Therefore, a wide range of the cornea can be observed and photographed even with extremely narrow slit illumination light. In addition, since narrow slit illumination light can be used, the light reflected by the corneal epithelium can be separated from the light reflected by the surface layer of the epithelium. As a result, a clear image of epithelial cells can be taken.
[0008]
The corneal cell imaging apparatus may further include an alignment optical system that irradiates alignment index light from the front of the eye to be examined and performs alignment using reflected light from the cornea.
[0009]
Since the above-described first slit and the second slit is formed in the same slit member, corneal cells imaging equipment that is configured such that the slit member is rotated, and a first slit and a second slit It becomes easy to move in synchronization. Further, the configuration of the apparatus is simplified, which is preferable.
[0010]
The alignment optical system has an anterior ocular segment imaging means, the slit member has a slit rotating means, the imaging optical system has a cornea imaging means, and the illumination optical system has An illumination light source, and in the plane formed by the optical axis from the oblique front to the anterior eye part in the illumination optical system and the optical axis extending obliquely forward from the anterior eye part in the photographing optical system, In the corneal cell imaging device, the eye imaging unit is arranged, and the slit rotating unit, the cornea imaging unit, and the illumination light source are arranged in a plane substantially parallel to a plane formed by the two optical axes. Is preferable because a plurality of devices can be efficiently accommodated in a small device housing, and the device can be made compact.
[0011]
Furthermore, it comprises a focusing optical system having a focusing light source that irradiates focusing light on the anterior eye portion of the eye to be examined from its oblique front, and a light receiving means that receives the focused reflected light in the anterior eye portion, A cornea in which the light receiving means has a first light receiving device and a second light receiving device for separately receiving the same in-focus reflected light, and both light receiving devices have different light receiving optical systems. In the cell imaging apparatus, it becomes easy to position the focal point of the imaging optical system on the epithelium.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The corneal cell imaging apparatus of the present invention will be described based on the embodiment shown in the accompanying drawings.
[0013]
FIG. 1 is a perspective view showing an embodiment of a corneal cell imaging apparatus of the present invention. FIG. 2 is a plan view of the corneal cell imaging apparatus of FIG. 3 is a rear view of the corneal cell imaging apparatus of FIG. 1 (viewed from the back of the apparatus toward the eye to be examined). FIG. 4 is a rear view showing an example of the slit plate in the corneal cell imaging apparatus of FIG. 1 (a view seen from the rear of the slit plate toward the eye to be examined). FIG. 5 is a rear view (a view seen from the back of the mask toward the eye to be examined) showing an example of the observation visual field mask in the corneal cell imaging apparatus of FIG. FIG. 6 is a cross-sectional view showing a cross section of the cornea of the eye to be examined.
[0014]
The corneal cell imaging apparatus 1 shown in FIGS. 1 to 3 is a machine frame (not shown) that can be moved in the Z direction that moves forward and backward toward the eye E and the X and Y directions that are perpendicular to the Z direction and perpendicular to each other. It has a photographing system 2 arranged on the top.
[0015]
The imaging system 2 illuminates the illumination optical system 4 for illuminating the anterior eye portion of the eye E with a slit light from the diagonally front, and the slit light reflected on the anterior eye surface of the eye E. The imaging optical system 5 and an alignment optical system for irradiating an alignment index light for imaging optical axis alignment (alignment) from the front toward the anterior eye portion of the eye E and imaging the corneal reflection light 6, a focusing optical system 7 for making the focal point of the photographing optical system 5 coincide with the corneal endothelium that is a photographing part, a rotary type that intersects the optical axis of the illumination optical system 4 and the optical axis of the photographing optical system 5. The slit plate 9 is provided.
[0016]
The illumination optical system 4 has a strobe discharge tube 8 as a light source for anterior segment illumination. Visible light from the strobe discharge tube 8 passes through a slit 19 formed in the slit plate 9, and this slit light is converged on the cornea of the eye E by the illumination lens 10. In the present embodiment, a cold mirror 11 is interposed in the middle of the optical path in order to make the optical path of the focusing optical system described later from the middle of the optical path of the illumination optical system 4. The cold mirror 11 reflects illumination light which is visible light and transmits focus detection light which will be described later, which is infrared light. A reference numeral 27 in FIG. 1 indicates a continuous observation lamp that continuously emits illumination light in order to continuously observe images of corneal cells.
[0017]
The photographing optical system 5 has a television camera 12 for photographing corneal cells. The slit light reflected by the cornea of the eye E is guided to the television camera 12 after passing through the photographing lens 13, the mirror 14 and the imaging lens 15. In the present embodiment, the optical path of the photographic optical system 5 is made the same as the optical path of the focusing optical system 7 to be described later halfway. For this purpose, a cold mirror 16 is provided for branching the optical path. The cold mirror 16 reflects illumination light that is visible light and transmits focus detection light that is infrared light.
[0018]
The alignment optical system 6 includes a light emitting diode 17 and a television camera 18 as a light source for alignment index light. Near-infrared light from the light-emitting diode 17 is irradiated from the front of the anterior eye portion of the eye E through the half mirror 22. Further, a bright spot (Purkinje image), which is a reflection image of the alignment index light on the cornea of the eye E to be examined, passes through the half mirror 22 and is sent to the television camera 18. Based on this Purkinje image, the photographing frame is moved in the XY directions so that the photographing optical axis coincides with the apex of the cornea.
[0019]
The slit plate 9 is rotated by a motor 20, and a plurality of slits 19 are formed on the circumference of the same radius from the rotation center 3 (see FIG. 4). In the present embodiment, the illumination light that has passed through one slit (hereinafter referred to as the first slit) 19 a is reflected by the anterior eye portion of the eye E, and the first slit 19 a is sandwiched between the rotation center 3 of the slit plate 9. The illumination optical system 4 and the photographing optical system 5 are disposed so as to pass through another slit (hereinafter referred to as a second slit) 19b positioned at 180 ° to reach the television camera 12. In addition, the slit illumination light moves on the anterior eye portion of the eye E as the first slit 19 a moves due to the rotation of the slit plate 9. The slit reflected light in the anterior eye portion also moves in the same manner, but the second slit 19b moves in accordance with the moving direction and moving speed of the moving slit reflected light. Thus, the illumination optical system 4 including the relay lens 25 and the mirror 14 and the optical devices of the photographing optical system 5 are arranged so that the illumination light and the reflected light can pass through the slits 19a and 19b that move in synchronization with each other. Arrangement has been made. The slits 19a and 19b are preferably formed to have the same width.
[0020]
With this configuration, the cornea of the eye E is scanned with the slit light. Therefore, a wide range of corneal cells can be observed and photographed even with slit light that illuminates a very narrow range. As shown in FIG. 4, the above scanning is repeated in a very short time by forming a range in which the slits 19 are formed at equal intervals on the slit plate 9 so as to be point-symmetric with respect to the rotation center 3. Therefore, it is possible to observe corneal cells as moving images. The slits do not have to be formed at regular intervals, and need not be formed over the entire circumference. However, by forming a plurality of slit areas symmetrically, it is possible to repeatedly scan even slit light that illuminates a very narrow range. As a result, the problem due to the small amount of illumination light can be solved. Further, the rotation direction of the slit plate 9 may be only one direction, or may be reciprocated with a predetermined stroke.
[0021]
As a result, it is possible to use slit illumination light having such a narrow width that the reflected light on the surface of the thin corneal surface (about 10 microns or less) and the reflected light on the corneal epithelium can be completely separated. That is, the slit 19 on the slit plate 9 is formed to have a width of about 0.05 to 0.2 mm, and the slit illumination light that has passed through the slit 19 is slit on the cornea by the lens system with a width of about 10 microns. Reduce to become illumination light. This reflected light is also magnified by the lens system of the photographing optical system 5.
[0022]
As shown in FIG. 5, a mask 28 having an observation visual field 28 a opened around the optical axis of the photographing optical system 5 in the slit plate 9 is disposed close to the slit plate 9. The size of the observation visual field 28a is not particularly limited, but in order to prevent image blurring, the width of the observation visual field 28a is made to substantially coincide with the formation interval of the slits 19 in the slit plate 9, and only one reflection slit light R passes at a time. You can do it.
[0023]
As shown in FIGS. 1 and 3, the corneal cell photographing camera (TV camera) 12, the anterior ocular segment observation camera (TV camera) 18, the slit plate 9, the motor 20, and the illumination means are respectively compared with other optical devices. It has a large volume. The illumination means includes an illumination light source (strobe discharge tube) 8 and a continuous observation lamp 27. The anterior ocular segment observation camera 18 is disposed in a plane formed by the optical axes 4 a and 5 a extending from obliquely forward to the eye E in the illumination optical system 4 and the photographing optical system 5. The corneal cell imaging camera 12, the slit plate 9, the motor 20, and the illumination means are all arranged in a lower surface in the figure than the surface on which the anterior segment observation camera 18 is disposed. It is a two-story arrangement. And the apparatus arrange | positioned in the lower surface in a figure is a corneal cell imaging camera arranged in parallel with the motor 20, the slit board 9, from the front (examined eye side) of the corneal cell imaging device 1 to back. 12 and the illumination means are arranged in this order. With such an arrangement, each device is accommodated in the apparatus housing in a proper manner, and the corneal cell imaging apparatus 1 is finished in a compact manner.
[0024]
Next, the focusing optical system 7 will be described. The focusing optical system 7 includes a focusing lamp 21 and a position sensor 23. The focus detection light that has passed through the slit 24 from the focus lamp 21 reaches the eye E along the optical axis 4 a of the illumination optical system 4, is reflected by the anterior eye portion, and is optical axis 5 a of the photographing optical system 5. To the position sensor 23 to receive light.
[0025]
That is, when the intersection (the above-mentioned focal point) of the optical axis 4a of the illumination optical system 4 and the optical axis 5a of the imaging optical system 5 is at the imaging region of the eye E, the position sensor 23 reflects the focus detection light. Detect light. At that time, illumination light and reflected light pass through the slits 19a and 19b, respectively. That is, the focal point of the photographic optical system 5 is set to the above-described focal point, and both the slits 19a and 19b are at conjugate positions with respect to the focal point. Then, the focal point is aligned with the photographing part of the eye E by moving the photographing system 2 in the Z direction in FIG. This alignment is called focusing.
[0026]
The position sensor includes a beam splitter 23c, and a first light receiving device 23a and a second light receiving device 23b that respectively receive light separated into two from the same reflected light by the beam splitter 23c. Both the light receiving devices 23a and 23b have slits. Both the light receiving devices 23a and 23b have light receiving optics for making the magnification of the image to be received, the width of the slit light, the wavelength of the received light, the polarization, etc. different from each other. By doing so, it becomes possible to easily focus on test sites having different properties. For example, a first light-receiving device 23a that can capture the position of the corneal endothelium and a second light-receiving device 23b that can identify and capture the position of the surface layer and the position of epithelial cells are combined. As a result, it is possible to clearly observe and take an image of epithelial cells, which has been difficult in the past.
[0027]
A reference numeral 29 in FIG. 1 indicates a fixation target light source for keeping the direction of the subject's eye constant by causing the subject's eye E to fixate.
[0028]
【The invention's effect】
According to the corneal cell imaging apparatus of the present invention, a clear image of each layer including the epithelium of the cornea can be obtained.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a corneal cell imaging apparatus of the present invention.
FIG. 2 is a plan view of the corneal cell imaging apparatus of FIG.
FIG. 3 is a rear view of the corneal cell imaging apparatus of FIG. 1;
4 is a rear view showing an example of a slit plate in the corneal cell imaging apparatus of FIG. 1. FIG.
5 is a rear view showing an example of an observation visual field mask in the corneal cell imaging apparatus of FIG. 1; FIG.
FIG. 6 is a cross-sectional view showing a cross section of a cornea of an eye to be examined.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Corneal cell imaging device 2 Imaging system 3 Center of rotation (of slit plate) 4 Illumination optical system 5 Imaging optical system 6 Alignment optical system 7 Focusing optical system 8 Strobe discharge tube 9 Slit plate 10 Illumination lens 11 Half mirror 12 Television camera 13 Shooting lens 14 Mirror 15 Imaging lens 16 Cold mirror 17 Light emitting diode 18 Television camera 19 Slit 19a First slit 19b Second slit 20 Motor 21 Focusing lamp 22 Half mirror 23 Position sensor 23a First light receiving device 23b Second light receiving device 23c Beam splitter 24 (for focusing lamp) slit 25 relay lens 27 continuous observation lamp 28 mask 28a observation visual field 29 fixation target light source C cornea E eye I endothelium R reflected light S surface layer,
U epithelium

Claims (6)

A rotary slit member in which the first slit and the second slit are formed point-symmetrically with respect to the rotation center;
Illumination for illuminating the anterior eye portion of the subject's eye from the oblique front with the slit illumination light that has passed through the first slit from the illumination light source and the illumination lens that is opposed to the illumination light source and the subject's eye Optical system,
And a photographing lens which faces in a state spaced in the cornea imaging means and the subject's eye, for taking by the cornea imaging means light reflected by the anterior segment of the slit illumination light through the second slit With a photographic optical system,
The reflected light travels I accompanied the movement of the first slit, so as to transmit it in synchronism with moving the second slit, the optical axis of the optical axis and the imaging optical system of the illumination optical system horizontally A corneal cell imaging apparatus in which mirrors that bend in the vertical direction and the vertical direction are provided . It further includes an alignment optical system that irradiates alignment index light from the front of the eye to be examined and performs alignment by reflected light from the cornea ,
The alignment optical system has an anterior ocular segment imaging means;
In the illumination optical system, the optical axis extending from the diagonally front to the anterior eye part and the optical axis extending diagonally forward from the anterior eye part in the photographing optical system are arranged to reach the anterior eye part. 2. The corneal cell according to claim 1, wherein the anterior eye imaging means is positioned so that the optical axis of the anterior eye imaging means is located and passes between the illumination lens and the imaging lens and reaches the eye to be examined. Shooting device. The mirror above
A first mirror that refracts the optical axis of the illumination optical system extending obliquely forward of the anterior eye part and the optical axis of the photographing optical system extending obliquely forward of the anterior eye part in opposite directions from each other;
A second mirror that bends both optical axes bent in this way in the same vertical direction;
The corneal cell imaging apparatus according to claim 1 or 2, further comprising a third mirror that bends both optical axes thus bent in the same direction in the front-rear direction to reach the illumination light source and the cornea imaging means. A first surface formed by an optical axis from the oblique front to the anterior eye part in the illumination optical system and an optical axis extending obliquely forward from the anterior eye part in the photographing optical system;
In the illumination optical system, the second surface formed by the optical axis passing through the first slit from the illumination light source and the optical axis extending through the second slit to the cornea photographing means in the photographing optical system are parallel to each other. like,
The corneal cell imaging device according to any one of claims 1 to 3, wherein the mirror is arranged . Upper Symbol slit member includes a motor as a slit rotating means,
The corneal cell imaging apparatus according to claim 4, wherein the motor is arranged such that a rotation axis thereof is located in the second surface . A focusing optical system having a focusing light source that irradiates focusing light from an oblique front of the anterior eye portion of the eye to be examined, and a light receiving means that receives the focused reflected light in the anterior eye portion;
The light receiving means has a first light receiving device and a second light receiving device for separately receiving the same focused reflected light,
The corneal cell imaging device according to any one of claims 1 to 5, wherein the two light receiving devices have different light receiving optical systems.

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