JPH08173387A - Cornea cell photographing system with cornea thickness measuring function - Google Patents

Abstract

PURPOSE: To provide a cornea cell photographing system in advantageous cost to perform photographing of endothelial cells of the cornea of an eye to be tested and simultaneously measuring cornea thickness without generating an error in the cornea thickness measurement even if the eye is moved, with little load on a testee since it is a cornea non-contact type, and without requiring another light receiving element for cornea thickness measurement except for the photographing element for cornea cell photographing. CONSTITUTION: A slit 2 for photographing in an illuminating light system to light an eye axis Ea of the cornea C of an eye to be tested from an oblique direction is formed as a thin width slit at an end in the longitudinal direction, and images respectively of thin width slit images are formed on the upper parts of mutually neighboring epithelial image and endothelial image on a photographing element 7 in an enlarging photographing optical system based on the slit illuminating light. Signals of the formed photographing image screen of a tested part are converted to the cornea thickness by measuring the interval of centers of the thin width slit images in a photographing signal processor 10 to show the enlarged image of the cornea endothelial cells and the cornea thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corneal cell imaging apparatus having a function of measuring corneal thickness together with corneal endothelial cell imaging.

[0002]

2. Description of the Related Art Conventionally, a corneal thickness measuring device called a pachometer for optically measuring the thickness of the cornea observes the reflected light from the eye to be inspected into which slit light is incident while rotating a parallel prism. It is known to measure the corneal thickness based on the rotation angle of the prism when the reflected light from the corneal epithelium / endothelium overlaps, and to the one improved in terms of measurement operation and measurement accuracy without using the prism, Japanese Patent Application Laid-Open No. 5-146409 discloses a device that photoelectrically converts a light flux reflected from the corneal epithelium / endothelium to measure the corneal thickness. On the other hand, the corneal endothelium imaging apparatus at present cannot generally measure the corneal thickness, and the pacometer, which is a separate device, is required for the corneal thickness measurement, and the corneal endothelial cells cannot be imaged by the pacometer.

The applicant previously described in Japanese Patent Application No. 5166132/1993 that a magnifying photographing optical system facing the spherical surface of the eye is moved in a non-contact state with respect to the spherical surface of the eye so that the slit light is incident on the cornea. While the corneal endothelium is imaged on the basis of the signal detected from the corneal endothelium focus of the reflected light from the
We proposed a device that can measure the corneal thickness by detecting the amount of movement of the photographic optical system from the focus position of the corneal epithelium to the focus position of the corneal endothelium detected respectively.

[0004]

As described above, the conventional corneal cell imaging apparatus generally cannot measure the corneal thickness during imaging of corneal endothelial cells, and the apparatus proposed by the applicant of the present invention has a photographic optical system The corneal thickness is calculated based on the amount of movement of the imaging optical system by the epithelial signal and the endothelium signal that are sequentially detected by moving in the direction of the eye to be inspected. There was a problem that an error would occur if it moved.

The present invention has been made in view of the above points, and does not cause a measurement error even when the eye moves during the measurement of corneal thickness, and it is a corneal non-contact type that burdens the subject. There is provided a corneal cell imaging apparatus having a small corneal thickness measuring function which is advantageous in terms of cost and does not require a separate light receiving element for corneal thickness measurement in addition to an imaging element for corneal endothelial cell imaging. The purpose is to

[0006]

In order to achieve the above object, in the present invention, as a corneal cell imaging apparatus having a corneal thickness measuring function, a slit is formed obliquely from the eye spherical surface of the eye to be inspected. In a corneal cell imaging apparatus having an illuminating optical system for illuminating and a magnifying observation means having a magnifying photographing optical system for observing by forming an enlarged image of a portion to be examined on an image sensor based on the slit illumination light, A slit for photographing of the illumination optical system is formed as a slit having a predetermined long narrow width at one end in the longitudinal direction, and the adjacent endothelium magnified image and epithelial magnified image on the memory image pickup screen in the magnifying observation means are in the same direction respectively. It comprises a means for measuring the center interval of the narrow slit images formed in the portion and a means for displaying the corneal thickness.

As the magnifying observation means, a frame memory for storing an image pickup screen and a monitor television for displaying the image pickup screen are provided, and an external input device such as a mouse is attached to the means for measuring the center interval of the narrow slits. It is a good idea to use a device that calculates and displays the corneal thickness according to the instructions of the endothelium center and the epithelial center on the monitor screen by the external input device.

As the magnifying and observing means, means for extracting adjacent side portions of the magnified endothelium image and epithelial magnified image on the side of the narrow slits on the imaging screen, and the magnified endothelium image and epithelial magnified image in the same direction, respectively. Equipped with a means to extract the narrow slit image formed on the side of the skin and a means to start a predetermined clock after the counter reset with the endothelial signal and stop with the epithelial signal to calculate and display the corneal thickness. It is very effective to use the one that has been prepared.

[0009]

According to the present invention, by adopting the structure described in claim 1, when enlarging and photographing the corneal endothelial cells of the eye to be inspected, the illumination light from the illumination optical system is slit to the eye spherical surface of the eye to be inspected. Through the imaging slit whose one end in the longitudinal direction is formed to have a predetermined narrow width, the eye axis is illuminated obliquely, and the reflected light from the cornea of the examined part based on this slit illumination light is magnified imaging optics of the magnifying observation means. A magnified image of the cornea to be inspected can be formed on the image pickup element through the system, and the magnified image of corneal cells can be displayed on the monitor television of the observation means. At this time,
The center interval of narrow slit images formed on the side in the same direction (for example, the upper side) of the adjacent magnified endothelium image and epithelial magnified image on the imaging screen that stores the image signal from the imaging device of the magnifying observation means is monitored on the monitor screen. The corneal thickness measured together with the magnified image of the endothelial cells can be displayed on the monitor television or other display means (printer or the like) by measuring the above or on the image signal with the measuring means.

When observing a magnified image of corneal endothelial cells with the magnifying and observing means, while measuring the corneal thickness, the magnifying and observing means displays a frame memory for storing an image-capturing screen and an image-capturing screen. By providing an external input device such as a mouse as a means for measuring the center interval of the narrow slit image by equipping the monitor TV, the narrow slit image of the endothelium and epithelium on the monitor screen with the external input device. By instructing the center of, the corneal thickness can be easily calculated and displayed from the manual.

When observing the magnified image of corneal endothelial cells by the magnifying and observing means, while measuring the corneal thickness, by adopting the configuration of claim 3, the adjoining endothelium is magnified from the image pickup screen stored in the magnifying and observing means. After extracting only the narrow slit side of the image and the enlarged epithelium image, the narrow slit images of the endothelium and epithelium are extracted and the counter signal is reset by the endothelium signal, and then a predetermined clock signal is generated continuously. By starting the counting and stopping the counting with the epithelial signal, the corneal thickness can be easily calculated from the obtained count value, and the corneal thickness can be displayed on the monitor television or other display means.

[0012]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram of an embodiment, and FIG. 2B shows a photographing slit plate used in the illumination optical system of the embodiment.

FIG. 1 shows an illumination optical system for illuminating the cornea C of the eye E to be examined, a magnifying photographing optical system for magnifying and photographing the illuminated corneal cells, and means for observing the magnified photographed image. A corneal cell imaging device provided with a magnifying observation means consisting of In the illumination optical system, as an illumination light source for the cornea C of the eye E to be inspected, an illumination light source 1 composed of an illumination lamp or a stroboscopic discharge tube is used, and the light emitted from the illumination light axis 1 is projected on the illumination optical axis 4 via the slit plate 2 and the projection lens 3. It is provided at a predetermined position on the illumination optical axis 4 so that the cornea C, which is the surface to be observed of the optometry E, is irradiated at a predetermined angle from the oblique direction with respect to the eye axis Ea.

On the opposite side of the illumination optical axis 4 of the illumination optical system and the eye axis Ea of the eye E to be examined, an oblique slit-shaped illumination light beam from an illumination light source 1 such as an illumination lamp or a stroboscopic discharge tube for the eye spherical surface C is provided. The reflected light from the cornea C of the cornea C causes an image of the corneal endothelial cells of the observed portion to be displayed on the imaging surface of the television camera 8 (CCD
A magnifying photographing optical system for magnifying observation / photographing by forming an image on the light receiving surface 7 is provided at a predetermined position on the optical axis 6 of the photographing lens 5
Are arranged.

The slit plate 2 provided on the illumination optical axis 4 has a slit for photographing in a direction perpendicular to the plane of the drawing.
As shown in FIG. 2 (B), the shape of a rectangular slit for photography provided on a conventional slit plate 2'as shown in FIG. It was formed in. Thereby, from the oblique direction of the eye axis Ea, the reflected light of the slit illumination light from the cornea C is passed through the imaging lens 5 by the television camera 8, and the image pickup element 7 of the television camera enlarges the endothelium image and the epithelium image. In the conventional device, a bright epithelium image is formed through the narrow gray zone as shown in FIG. 3 (A) when the images are simultaneously captured. Although it is not possible to measure the distance between the center of the endothelium and the center of the epithelium because the center position of is not known, by forming one side of the slit for photography with a predetermined width into a slit with a predetermined length as described above,
As shown in FIG. 3B, it is possible to measure the center interval d of the narrow slit images formed on the side portions (the upper portion in the embodiment) of the endothelium image and the epithelial image, respectively, in the same direction. in this case,
In the image pickup device 7 of the television camera, the center interval d is
Since the imaging is performed obliquely to the eye axis Ea, it is smaller than the actual corneal thickness.

That is, as shown in FIG.
When SL is obliquely irradiated to the eye axis Ea and the epithelium and endothelium of the cornea C are simultaneously imaged, the reflected light of the slit light SL is reflected at the same angle θ with respect to the eye axis Ea, The distance between the corneal epithelium C ₁ and the corneal endothelium C ₂ due to the reflected light when viewed from the imaging direction on the ocular axis is the center distance d of the narrow slit image on the imaging screen, and d = if the corneal thickness is n. n sin θ is smaller than the actual corneal thickness, and corneal thickness n = d / sin θ. Therefore, the corneal thickness is calculated by converting the actual center distance in the image pickup signal processing device 10 from the center distance d of the narrow slit images measured on the image pickup screen [FIG. 3 (B)] by the image pickup signal from the television camera 8. It can be obtained and displayed on the monitor TV 12 or the like.

Next, two embodiments of the image pickup signal processing unit for calculating and displaying the corneal thickness from the corneal magnified image picked up by the optical system of this apparatus will be described. [Embodiment 1] FIG. 5 is a block diagram showing a circuit configuration of the embodiment. The optical system 9 shown in FIG. 5 has the configuration of the optical system shown in FIG.
The alignment control and imaging control signal a input from the general control unit 10 ₁ having a U or other circuits, after the X-Y-Z direction alignment of the optical system 9 with respect to the eye (alignment) , It is designed to perform corneal radiography.

The image signal of the photographed cornea, the frame memory 11 from the optical system 9, the captured by freeze control signal b to the frame memory 11 from the general control unit 10 ₁ is stored. Corneal image signal stored in the frame memory 11, an image shown in FIG. 3 (B) are called in signal C from the general control unit 10 ₁ is input to the monitor television 12 is supposed to be displayed . Further, the general control unit 10 ₁ is connected mouse 14, the upper portion of the endothelium image epithelial image of the imaging screen of the monitor television 12 moved the mouse cursor on the monitor television 12 by moving the mouse 14 said position by instructing the center of each of the elongated slit images formed right and left is input to the comprehensive controller 10 ₁ at a said general control unit 11, the incident angle θ calculated at the time (alignment
The corneal thickness is calculated by a predetermined calculation formula n = d / sin θ (using the center distance d indicated by the center position) and displayed on the screen of the monitor television 12. When the cornea thickness is calculated by the instructions of the center of the endothelium and the center of the epithelium using this mouse 14, and is displayed on the monitor TV 12, the corneal endothelium image automatically photographed from the printer 13 and the measured corneal thickness are displayed on the corneal epithelium part. It is designed to be printed out.

Next, the measurement of corneal thickness in Example 1
The display procedure will be described based on the flowchart shown in FIG. First, the optical system 9 including the illumination optical system and the magnifying imaging optical system of the present device is aligned with the cornea C of the eye E in the X, Y, and Z directions (positioning including focusing), and the corneal endothelium. The magnified image of the cells is taken together with the magnified image of the epithelium. As a result of this photographing, as shown in FIG. 3 (B), an image in which a narrow slit image is formed at the upper part of each of the magnified endothelium and magnified epithelium adjacent to each other through the gray zone is imaged, and this imaging screen is a frame. together are uptake stored in the memory 11, it is reproduced and displayed on the monitor television 12 in the signal C from the general control unit 10 _1. At this time, the examiner moves the mouse 14 while looking at the monitor screen to position the mouse cursor at the center of each of the narrow slit images of the endothelium and epithelium on the monitor screen, and center the endothelium and the center of the epithelium. Instruct.
As a result, the distance d between the center of the endothelium and the center of the epithelium on the monitor screen
Predetermined formula corneal thickness are input to the comprehensive controller 10 ₁ n = d
The corneal thickness is calculated by / sinθ. Then, the corneal thickness is displayed on the monitor screen together with the endothelium image and the epithelial image, for example, and the paper on which the corneal thickness, the endothelial cell enlarged image, and the epithelial image portion are displayed is printed out from the printer 13 at the same time. As a result, it is possible to easily obtain accurate measurement data of corneal thickness together with a magnified image of corneal endothelial cells by a simple manual operation. In addition, in the above-mentioned example, although the center interval of the narrow slit images of the endothelium and the epithelium is measured,
Of course, the right end interval or the left end interval of the narrow slit image may be measured, and further, the right end of the endothelium image and the right end of the epithelial image or the left end of the endothelium image and the left end of the epithelial image may be measured.

[Embodiment 2] FIG. 6 is a block diagram showing a circuit configuration of the embodiment. The optical system 9 in FIG. 6 has the configuration of the optical system shown in FIG. 1, and like the first embodiment, the integrated control unit 10 ₁ (see FIG. 6) provided in the imaging signal processing device 10 (see FIG. 1). Input of the alignment control / imaging control signal a from the reference), the X of the optical system 9 with respect to the eye to be inspected.
・ Cornea imaging is performed after alignment (positioning) in the Y and Z directions.

The photographed image signal of the cornea is taken into the frame memory 11 from the optical system 9 and stored therein, and is also inputted to the mask circuit 15, and in the mask circuit, the narrow width for detecting the corneal thickness of the image pickup screen is inputted. Only the upper part including the slit image part [see FIG. 3 (b)] is detected. The detected signal of the upper part is input to the comparator 16, and the lightness and darkness of the image are compared to extract a bright portion, that is, only a narrow slit image portion for detecting the corneal thickness of the endothelium and the epithelium. The signals of the narrow slit image portions of the endothelium and the epithelium extracted are input to the counter 18. A clock signal is constantly input from the clock 17 to the counter 18, and the counter 18 is configured to start counting after the counter is reset by the endothelial signal and stop counting by the epithelial signal. signal corresponding to the d inputs to the comprehensive controller 10 _1. And it calculates the corneal thickness by a predetermined calculation formula from the general control unit 10 ₁ input count signal.

[0022] The general control unit 10 ₁ is connected to an operation panel 19 including operation buttons, together with the alignment control and imaging control of the optical system by button operation, the endothelium image displayed on the monitor television 12 described later The display image of the corneal thickness and the like can be printed out from the printer 13.

[0023] as well as display reads endothelium image the image signal stored in the frame memory 11 is only endothelium image portion is called the signal C from the general control unit 10 ₁ to the monitor television 12, the comprehensive controller 10 corneal thickness of the signal calculated by ₁ is to the monitor television 12 and input to the TV monitor 12 also the signal C from the general control unit 10 ₁ adapted to be synthesized and displayed with endothelium image. And if necessary, the operation panel 19
By operating the button at, it is possible to obtain a paper on which the magnified image of corneal endothelial cells and the corneal thickness are printed out from the printer 13.

Next, the procedure for measuring and displaying the corneal thickness in the second embodiment will be described with reference to the flowchart shown in FIG. First, the optical system 9 including the illumination optical system and the magnifying imaging optical system of the present device is aligned with the cornea C of the eye E in the X, Y, and Z directions (positioning including focusing), and the corneal endothelium. The magnified image is taken together with the magnified image of the epithelium. As a result of this photography, as shown in FIG.
Images in which narrow slit images are formed are respectively captured on the upper part of the endothelium magnified image and the epithelium magnified image which are adjacent to each other via the gray zone, and the imaging screen is captured and stored in the frame memory 11 and the general control unit 10 ₁ Only the endothelium image is reproduced / displayed on the monitor television 12 by the signal C from.

On the other hand, the photographed image signals of the corneal endothelium and epithelium are input to the mask circuit 15 from the optical system 9, and only the upper portion including the narrow slit image portion for detecting the corneal thickness is detected in the mask circuit 15. . The detected upper signal is input to the comparator 16, and the comparator circuit compares the lightness and darkness of the image to extract only the narrow slit image portion for detecting the corneal thickness of the endothelium and the epithelium in a bright place. Next, the signal of the narrow slit image portion of the extracted endothelium and epithelium is input to the counter 18, and the counter 18 is reset by the endothelium signal using the predetermined clock signal that is constantly input, and the count is started. And stop counting with the epithelial signal,
Count signal is calculated by a predetermined calculation formula comprehensive controller 10 ₁ calculates the corneal thickness. Calculated corneal thickness of the signal is input from the general control unit 10 ₁ to the monitor television 12, the monitor TV 12, is synthesized and displayed with the endothelium image. Then, by operating the buttons on the operation panel 19,
From the printer 13, a paper on which the magnified image of corneal endothelial cells and the corneal thickness are displayed is printed out. By using a mouse, it is possible to obtain accurate measurement data of corneal thickness automatically with a magnified image of corneal endothelial cells with a simple operation without the need to specify the center of endothelium and the center of epithelium on the monitor screen using a mouse. You can In the above-mentioned embodiment, after the counter is reset with the endothelial signal, the predetermined clock is started and stopped with the epithelial signal to perform the counting for the corneal thickness measurement. The clock may be started by the signal and stopped by the endothelium signal.

[0026]

According to the corneal cell imaging apparatus having the corneal thickness measuring function of the present invention as set forth in claim 1, when the corneal thickness is measured together with the magnified imaging of corneal endothelial cells, the measurement is performed even when the eye moves. A cost that does not cause an error, is less of a burden on the subject with a non-corneal contact type, and does not require a light-receiving element for measuring corneal thickness other than an imaging element for imaging corneal cells. It is possible to provide a corneal cell imaging device having a corneal thickness measurement function which is advantageous in terms of the aspect.

According to the second aspect of the invention, an external input device such as a mouse is attached as a means for measuring the corneal thickness, and the corneal thickness is measured by designating a predetermined position on the photographed image on the monitor screen. Therefore, it is possible to provide a corneal cell imaging apparatus equipped with a function of measuring the corneal thickness, which has a small number of components that can easily calculate and display the corneal thickness by a simple manual operation and has a low cost. .

According to the third aspect of the present invention, an external input device such as a mouse for measuring the corneal thickness is not required, and the corneal thickness can be automatically calculated and displayed at the time of photographing the corneal endothelial cells. It is possible to provide a corneal cell imaging apparatus having a corneal thickness measurement function capable of omitting the thickness measurement operation.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention,

FIG. 2 is an explanatory view showing a shape change of a photographing slit,

FIG. 3 is an explanatory view of changing a shape of a photographed image by changing a shape of a slit for photographing,

FIG. 4 is an explanatory diagram of corneal thickness conversion by obliquely capturing an image on the eye axis,

FIG. 5 is a block diagram of Embodiment 1 of the present invention,

FIG. 6 is a block diagram of a second embodiment of the present invention,

FIG. 7 is a flowchart showing a procedure for measuring corneal thickness in Example 1,

FIG. 8 is a flowchart showing a procedure for measuring corneal thickness in Example 2.

[Explanation of symbols]

1 ... Light source, 2 ... Shooting slit plate, 3 ... Projection lens, 4 ... Illumination optical system optical axis, 5 ... Imaging lens, 6 ...
Enlarged photographic optical system optical axis, 7 ... imaging device, 8 ... TV camera, 9 ... optical system (total), 10 ... image signal processing apparatus, 10 ₁ ... Overall control unit, 11 ... frame memory,
12 ... Monitor TV, 13 ... Printer, 14 ... Mouse,
15 ... Mask circuit, 16 ... Comparator, 17 ... Clock, 18 ... Counter, C ... Corneal, C ₁ ... Corneal epithelium,
C ₂ ... corneal endothelium, d ... corneal thickness seen from the imaging direction, E
... eye (eyeball), n ... corneal thickness.

Claims (3)

[Claims] 1. An illumination optical system for slit-illuminating an eye spherical surface of an eye to be examined from an oblique direction to an eye axis, and an enlarged image of a subject to be examined is formed on an image pickup device based on the slit illumination light for observation. In a corneal cell imaging apparatus equipped with a magnifying observation means having a magnifying imaging optical system to do so, while forming the imaging slit of the illumination optical system in a predetermined length narrow slit at one end in the longitudinal direction, in the magnifying observation means Means for measuring the center interval of narrow slit images formed on the side portions of the adjacent magnified endothelium image and magnified epithelial image adjacent to each other on the memory image pickup screen and means for displaying the corneal thickness A corneal cell imaging device equipped with a corneal thickness measurement function. 2. The magnifying observation means comprises a frame memory for storing an image pickup screen and a monitor television for displaying the image pickup screen, and an external input device such as a mouse is attached to the means for measuring the center interval of the narrow slits. The corneal thickness is calculated and displayed by an instruction of the center of endothelium and the center of epithelium on a monitor screen by the external input device.
A corneal cell imaging apparatus having the described corneal thickness measurement function. 3. The magnifying and observing means is the same as the means for extracting adjacent side portions of the magnified endothelium image and the epithelial magnified image on the narrow slit side of the adjacent magnified image of the endothelium and the magnified endothelium image, respectively. It is equipped with a means for extracting narrow slit images formed on the side in the direction and means for counting and starting the predetermined clock after the counter reset with the endothelial signal and stopping with the epithelial signal so that the corneal thickness can be calculated and displayed. A corneal cell imaging apparatus having a corneal thickness measurement function according to claim 1 or 2.