JPH07148116A - Cornea-cell phtographing apparatus - Google Patents

Abstract

PURPOSE:To provide a cornea-cell photographing apparatus capable of focussing the corneal endothelium precisely and easily and also of detecting the reflection on the epithelium precisely when the enlarged image of the corneal endothelium cell of a subject eye is taken, as well as of measuring thickness of the cornea easily and securely. CONSTITUTION:When the eyeball surface 2 is given the slit lighting and the endothelial image of the subject is formed in the right focus on the receiving surface 22 of a TV camera 23 by way of the enlarged photographing optical systems based on the lighting, a light detecting element (a) for detecting the focussing situation of endothelium is placed at the position to receive the slit light reflected on the cornea on a light axis 14 passing through an objective lens 15, and in the same way, a light detecting element (b) for detecting the focussing situation of epithelium is placed on a light axis 14 divirging from the light axis 14. For two light detecting elements (a), (b) the optimum elements are used respectively to meet their purposes, and in calculation of the corneal thickness, a line sensor and others in use of detecting the endothelial reflection light by the element (a) are adjusted to the corresponding position the epithelial reflection light is received by the element (b), for the calculation of the corneal 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 state photographing apparatus for magnifying observation or photographing a corneal endothelial cell of an eyeball of a subject, and more particularly to corneal cell photographing advantageous for corneal thickness measurement. Regarding the device.

[0002]

2. Description of the Related Art To see the effects of contact lenses,
It is necessary to observe the state of corneal endothelium in preoperative and postoperative medical care for cataract surgery. On the other hand, the objective lens of the microscope is a non-contact type or a contact type, and the slit illumination light is radiated toward the observed part obliquely with respect to the eye axis to separate the reflected light from the corneal surface and the image light rays of the endothelial cells. Various devices have been used in which the corneal endothelial cells in the test area are photographed by a television camera or the like. In order to eliminate the troublesome operation of these conventional devices, the present applicant has previously filed Japanese Patent Application No. 05-166132 (June 1, 1993).
(0th day application), it is possible to automatically perform the enlarged observation or the enlarged photograph of the corneal endothelial cells in the examined portion, and simultaneously measure the corneal thickness of the eye to be examined at the same time as the enlarged observation or the enlarged photograph. Proposed a device. In this device, when measuring the corneal thickness, two reflected lights from the corneal epithelium and the corneal endothelium were detected by one light receiving element.

[0003]

However, the above two reflected lights are strong in epithelial reflected light and weak in endothelial reflected light, and the difference between the two is large, so it is difficult to reliably and accurately detect these two reflected lights. There was a problem. Therefore, the applicant of the present application has proposed, in Japanese Patent Application No. 05-241986 (filed on September 2, 1993), an improvement for surely detecting corneal endothelium reflected light that is significantly weaker than corneal epithelium reflected light. Then, by the improvement, the corneal endothelium reflected light can be reliably detected with high accuracy. However, for the measurement of corneal thickness, it is still necessary to detect epithelial reflex with high accuracy at the same time.

The present invention has been made in view of the above circumstances, and can easily and accurately focus the corneal endothelium of the subject, and also detect the epithelial reflex with high accuracy. It is an object of the present invention to provide a corneal cell imaging device that can perform corneal thickness measurement easily and reliably.

[0005]

In order to achieve the above object, in the present invention, an illumination optical system for slit-illuminating an eye spherical surface of an eye to be inspected, and a portion to be inspected based on slit illumination light illuminating the eye spherical surface. A magnifying photographing optical system for forming and observing and photographing a magnified image, and a cornea of slit light through an objective lens at least when a corneal endothelium image is focused on the image plane of the magnifying photographing optical system. A cornea composed of a focus detection light receiving element set at a position for receiving the endothelium reflected light or the corneal epithelium reflected light, and a means for moving the apparatus main body toward the eye to be inspected so as to come to the corneal endothelium focused position. In the cell imaging apparatus, two light receiving elements, that is, a light receiving element a for receiving corneal endothelium reflected light and a light receiving element b for receiving corneal epithelium reflected light are used as the focus detecting light receiving elements.

A light receiving element b for receiving the reflected light from the corneal epithelium
As a light receiving element capable of detecting the movement amount of the epithelium reflected light in the moving direction, and the light receiving element a for receiving the corneal endothelium reflected light receives the corneal epithelium reflected light when the endothelium reflected light is detected. It is effective to configure the corneal cell imaging device so as to calculate the corneal thickness corresponding to the epithelium reflected light receiving position on the light receiving element b.

[0007]

In this device, the magnified image of the corneal endothelium of the subject is formed by the magnifying photographing optical system based on the reflected light from the spherical surface of the eye which is slit-illuminated by the illumination system. In this case, as shown in the optical path diagram of the corneal cell imaging apparatus in FIG. 1, the imaging system 3 is manually or automatically advanced to the direction of the eye to be inspected and the imaging system 3 is moved.
When there is a relative movement between the eye and the subject's eye, the vertically long slit illumination light projected from the illumination lamp 4 to the cornea 2 through the illumination system is reflected by the epithelial surface of the cornea 2 and slit-shaped through the objective lens 15. The epithelium reflected light is the light receiving element a for detecting the endothelium focus.
The illumination light that has moved through the anterior surface of the corneal epithelium is reflected on the corneal endothelium surface deeper than the corneal epithelial surface on the illumination optical axis 12 and slit-shaped endothelium reflected light through the objective lens 15 as well, Following the slit-shaped epithelial reflected light, the front surface of the endothelium focus detection light-receiving element a is moved in a state of adjoining with a small gap.

On the other hand, the other epithelial focus located on the optical axis 14 ₂ focus detection light receiving elements b of the detecting light-receiving elements a and separately expanded imaging optical system endothelium focal Following the same epithelial reflected light The endothelium reflected light moves on the front surface of the epithelial focusing detection light receiving element b. Then, when the corneal reflected light of the corneal reflected light moving on the front surface of the light receiving element a is incident on the light receiving area of the light receiving element a and the focused state of the endothelium is detected, an enlarged corneal endothelium image of the test portion is detected. Is focused on the image receiving surface 22 of the TV camera 23, and the strobe discharge tube 8 of the illumination system emits light to cause the TV camera
The image of the corneal endothelial cells magnified by the monitor 23 (see FIG. 2) can be observed or photographed from the monitor 23. In this case, a light receiving element (for example, a phototransistor) which is most suitable for detecting the reflected endothelium is used as the light receiving element a for detecting the endothelium focusing, and a light receiving element which is optimum for detecting the epithelium reflected light is used as the light receiving element b for detecting the epithelium focusing. Element (eg line sensor, PSD, etc.)
By using, the respective light receiving optical paths can be devised according to the application without concern about mutual influences, the degree of freedom in design is increased, and the light receiving function can be easily adjusted. As a result, the endothelium can be easily and accurately detected, and the epithelium position when the endothelium is detected can be accurately detected.

As the light receiving element b for receiving the corneal epithelium reflected light, a light receiving element capable of detecting the amount of movement in the epithelium reflected light moving direction is used, and the light receiving element a for receiving the corneal endothelium reflected light receives the endothelium reflected light. A machine which is a movement amount detecting means in the previous application (Japanese Patent Application No. 05-166132) by calculating the corneal thickness corresponding to the light receiving position of the epithelium reflected light on the light receiving element b when detected. Corneal thickness can be easily measured electronically without using a conventional encoder. A CCD camera for image pickup may be used as the light receiving element b.

[0010]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is an optical path diagram of the above embodiment, and FIG. 2 is a block diagram of an electric circuit of the above embodiment.

In FIG. 1, an illumination system for slit-illuminating an eye spherical surface 2 of an eye 1 to be inspected and a slit illumination light illuminating the eye spherical surface facing the eye spherical surface 2 are used to magnify and observe an object to be inspected by a television camera 23. It consists was allow an enlarged photograph enlarged and the photographing optical system, and the imaging matching position by detecting the corneal endothelial reflected light of the test section a portion 14 ₁ extending in the optical path of the enlarged image taking optical system A corneal endothelium focusing detection light receiving element a for detection is provided, and the optical axis 14 ₂ is branched from the optical axis 14 ₁ of the magnifying photographing optical system and is arranged 45 ° crossing with the optical axis 14 _2. With respect to the reflecting surface of the infrared light transmitting / visible light reflecting mirror 21, the corneal epithelium focusing detection light receiving element b arranged so as to have a light receiving surface at a conjugate position with the image receiving surface 22 of the television camera is The focus of the slit is detected and it is long in the moving direction of the slit reflected light. The light-receiving surface, is detectably form the moving amount of the moving direction of the epithelium reflected light.

As an illumination light source for the portion to be examined on the eye spherical surface 2, an illumination lamp 4 used during focusing of the magnifying and photographing optical system.
And the stroboscopic discharge tube 8 used at the time of taking a magnified photograph of the corneal endothelial cells, the respective light emitted from the illumination optical axis 12 through the projection lens 13 to the cornea 2 which is the surface to be observed of the eye 1 to be inspected,
The stroboscopic discharge tube 8 illuminates at a predetermined position on the illumination optical axis 12 and the illumination lamp 4 illuminates via the half mirror 11 on the illumination optical axis 12 so as to irradiate the eye axis at a predetermined angle from the oblique direction. It is provided on the optical axis perpendicular to the optical axis 12. Then, the light emitted from the illumination lamp 4 is provided with a narrow slit slit 7 for detection corresponding to the slit aperture 17 on the front surface of the corneal endothelium focusing detection light receiving element a at the focus position by the condenser lens 5. The light emitted from the stroboscopic discharge tube 8 is focused at a focus position by the condenser lens 9 and has a predetermined wide slit slit 10 for photographing so that a wide field of view can be photographed.
And a visible light cut filter 6 is provided on the optical axis of the illumination lamp 4 in front of the detection slit 7.
Only the infrared light of the light of the illumination lamp 4 is reflected by the half mirror 11 which reflects and transmits the infrared light and is projected onto the eye spherical surface 2, while the visible light of the strobe discharge tube 8 is reflected by the half mirror 11.
To be projected onto the eye spherical surface 2.

Further, on the opposite side of the axial 2 ₁ of the eye and the illumination optical axis 12 of the illumination system, the cornea of the oblique slit-shaped illumination light by the illumination lamp 4 or the strobe discharge tube 8 to the eyeball surface 2 An image of the corneal endothelium of the observed part upon receiving the reflected light from the image 2 is received on the image receiving surface (CCD light receiving surface) 22 of the television camera 23.
A magnifying photographing optical system for magnifying observation or photographing a magnified image by being formed on the image capturing device is provided, and when the corneal endothelium image is focused on the image receiving surface 22 of the television camera 23, the optical path of the optical system is changed. is set to a position obtained by extending a portion 14 ₁ corneal endothelium focusing detection light receiving element a is focusing by detecting the corneal endothelial reflected light to move the front of the light receiving element a with the forward movement of the imaging system 3 It is designed to detect

[0014] That is, the optical axis of the enlarged image taking optical system in the illumination optical axis 12 and symmetrical position of the illumination system across the axial 2 ₁ of the eye 1
An objective lens 15 on the eyeball side at a predetermined position on 14 ₁ and a half mirror (infrared light transmission / visible light reflection) 16 at a predetermined distance from the objective lens 15 and a predetermined distance from the optical axis 14 ₁ an image light by the reflected light of the illumination light from the angle crossed to the eyeball surface is arranged to bending so as to be perpendicular to the predetermined position of the substantially axial line of the axial 2 _1, the image light reflected by the half mirror 16 enlarged image light by the optical axis 14 ₂ up through the field stop 19 and the magnifying lens 20 is located on an intermediate image plane the axial 2 ₁ direction 45 ° cross the infrared light transmission and visible reflection of the half mirror 21 while visible light imaging slit light by the strobe light is incident to the total reflection, the image receiving surface (CCD light-receiving surface) 22 of the TV camera 23 provided on the optical axis 14 ₃ which is bent out of,
The infrared light of the slit light for detecting the photographing position (corneal endothelium in-focus position) extends the optical path on the optical axis 14 ₁ and the objective lens 15
The cornea reflected image light beam is incident on the corneal endothelium focus detection light receiving element a provided at the image forming position. When the corneal endothelium image is focused on the image receiving surface 22 of the television camera 23 by the objective lens 15 and the magnifying lens 20, the slit-shaped corneal endothelium reflected light for focus detection is used for endothelium focus detection. The slit diaphragm 17 which is long in the longitudinal direction of the corneal reflection image in front of the light receiving element a facilitates separation from the epithelial reflection with a lot of flare that is close thereto, and the slit diaphragm 7 at the focus position of the light emitted from the illumination lamp 4 narrows the width. Then, the light is incident on the light receiving area of the light receiving element a, and the light receiving element a can detect the corneal endothelium reflected light with high position accuracy to detect the photographing suitable position (focus position) of the apparatus. in this case,
The corneal endothelium focus detection light-receiving element a can easily and accurately perform corneal endothelium focus detection by using a phototransistor as an optimal light-receiving element for corneal endothelium focus detection.

The objective lens 15 and the magnifying lens 20 are also provided.
The slit-shaped epithelium reflected light of infrared light in the image light expanded by is passed through the half mirror 21 and is focused on the epithelial focus detection light-receiving element b to detect epithelial focus.
As the imaging system 3 moves forward, it moves on the surface of the light receiving element b. In this case, by using a line sensor as the light receiving element b for epithelial focusing, the light receiving element b for epithelial focusing detects the epithelial focusing, and then the light receiving element a for endothelium focusing detects a focus on the endothelium. The epithelium reflected light position moved from the epithelial focus detection position at the time of detection can be accurately detected, and the corneal thickness can be calculated from the amount of movement. The photographing system 3 operates with the electric circuit shown in FIG.

Next, the operation procedure of the corneal cell imaging apparatus according to the present invention will be described based on the block diagram shown in FIG. 2 and the flowchart shown in FIG. First, after turning on a power source (not shown) of the corneal cell imaging apparatus, the optical system which is the imaging system 3 is manually aligned with the eye to be inspected (centering of the pupil center and the television image), and then the Z-axis drive mechanism 35. Drive the Z-axis to move it forward in the direction of the subject's eye. While the imaging system 3 is moving forward, the endothelium focusing detection light-receiving element a senses the corneal epithelium reflected light, while the epithelial reflection light reaches the epithelial focusing detection light-receiving element b on another optical path. When the photographing system 3 continues to move forward, the light receiving element a for detecting the focus of the endothelium receives the endothelium reflected light, and the slit light reflection detection circuit 36 detects the corneal endothelium reflected light. The strobe light emission control circuit 37 is activated by the signal and the strobe discharge tube 8 emits light, and the reflected light from the eye spherical surface 2 passes through the optical path of the magnifying and photographing optical system to form a magnified image of the subject on the light receiving surface of the television camera 23. The image signal of the magnified image of the corneal endothelial cells of the subject from the television camera 23 is written in the frame memory 32 by the image input / output control circuit 31, and at the same time, the image input / output control circuit 31.
The Z-axis drive mechanism 35 stops the advance of the imaging system 3 in response to the signal from and the monitor display 33 displays an enlarged image of the corneal endothelial cells.

On the other hand, when the light receiving element a detects the endothelium reflected light, the epithelial reflected light reaches the light receiving element b first and then moves, and the position of the moved epithelium reflected light on the light receiving element b is Corneal thickness calculation circuit via slit light reflection detection circuit 36
The corneal thickness calculation circuit 38 calculates the corneal thickness corresponding to the moved epithelial reflected light position on the light receiving element b, and the corneal thickness calculation circuit 38 calculates the corneal thickness along with the magnified image of the corneal endothelial cells via the image input / output control circuit 31. The image is displayed on the monitor display unit 33 and the photographing ends. In this case, there is no movable part such as a rotary encoder, and the corneal thickness can be calculated advantageously. Further, the corneal thickness is stored in the frame memory 32 via the image input / output control circuit 31.
The corneal endothelial cell magnified image and the corneal thickness can be read out from the frame memory 32 by the image input / output control circuit 31 as necessary and can be ejected from the video printer 34. Can be attached to the chart.

In this embodiment, the corneal endothelium reflected light of the corneal reflected light is highly sensitive to weak endothelium reflected light by using a light receiving element (eg, phototransistor) which is optimal for detecting the endothelium reflected light. Of the epithelium reflected light can be detected by using a line sensor, PSD or the like that can detect the amount of movement of the corneal epithelium reflected light in the moving direction of the epithelium reflected light, The amount can be easily detected, and the corneal thickness calculation circuit can easily and accurately calculate the corneal thickness.

[0019]

According to the corneal cell imaging apparatus of the first aspect, when observing and photographing a magnified image of corneal endothelial cells of the eyeball of a subject, the corneal endothelium focusing of the imaging apparatus can be performed manually or automatically. In addition, it is possible to easily carry out the above, and it is possible to use a light receiving element which is optimum for detecting reflected light from each of the corneal endothelium and corneal epithelium. Further, the respective light receiving optical paths can be devised according to the application without concern about mutual influences, the degree of freedom in design can be increased, and the adjustment of the light receiving function can be facilitated. As a result, the corneal endothelium can be easily and accurately detected, and the epithelial position when the endothelium is detected can be accurately detected.

According to the corneal cell imaging apparatus of the second aspect, when the corneal thickness is calculated together with the magnified imaging of the corneal endothelium, it is not necessary to use a measuring means such as a mechanical encoder and the electronic measuring means is used. The corneal thickness can be easily measured.

[Brief description of drawings]

FIG. 1 is an optical path diagram of an embodiment of the present invention,

FIG. 2 is a block diagram of an embodiment of the present invention,

FIG. 3 is a flowchart showing a procedure of corneal endothelium imaging / corneal thickness calculation.

[Explanation of symbols]

1 ... Eyeball, 2 ... Eye spherical surface (cornea), 3 ... Imaging system, 4
... Illumination lamp, 7 ... Slit diaphragm for detection, 8 ... Strobe discharge tube, 10 ... Slit diaphragm for photography, 11 ... Infrared light reflection / visible light transmission mirror, 12 ... Illumination optical axis, 13 ... Projection lens, 141 _. 14 ₂ , 14 ₃ … Magnification optical system optical axis, 15… Objective lens, 16… Infrared light transmitting / visible light reflecting mirror, 17…
Slit diaphragm, 20… Magnifying lens, 21… Infrared transmitting / visible light reflecting mirror, 22… CCD light receiving surface (image receiving surface), 23
... TV camera, 31 ... Image input / output control circuit, 32 ... Frame memory, 33 monitor display, 34 ... Video printer, 35 ... Z-axis drive mechanism, 36 ... Slit light reflection detection circuit, 37 ... Strobe light emission control circuit, 38 ... corneal thickness calculation circuit, a ... light receiving element for endothelium focusing detection, b ... light receiving element for epithelial focusing detection.

Claims (2)

[Claims] 1. An illumination optical system for slit-illuminating an eye spherical surface of an eye to be inspected, and a magnifying photographing optical system for forming and observing and photographing a magnified image of a portion to be inspected based on slit illumination light irradiating the eye spherical surface. When a corneal endothelium image is focused on the imaging plane of the magnifying imaging optical system, it is set at a position to receive the corneal endothelium reflected light of slit light or the corneal epithelium reflected light of at least the objective lens. In a corneal cell imaging apparatus comprising a focus detection light-receiving element and means for moving the apparatus main body in the direction of the eye to be inspected so as to come to the corneal endothelium in-focus position, the focus detection light-receiving element emits corneal endothelium reflected light. A light receiving element a for receiving light,
A corneal cell imaging apparatus comprising a light receiving element b for receiving corneal epithelium reflected light. 2. A light receiving element b for receiving the light reflected by the corneal epithelium.
Is a light receiving element capable of detecting the movement amount of the epithelium reflected light in the moving direction, and receives the corneal epithelium reflected light when the light receiving element a for receiving the corneal endothelium reflected light detects the endothelium reflected light The corneal cell imaging apparatus according to claim 1, wherein the corneal thickness is calculated corresponding to the light receiving position of the epithelium reflected light on the light receiving element b.