JP3316067B2 - Corneal cell imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for photographing a state of a corneal cell for magnifying or photographing a corneal endothelial cell of a subject's eyeball, and more particularly to a corneal cell photographing apparatus which is advantageous for measuring a corneal thickness. Related to the device.

[0002]

2. Description of the Related Art To see the effects of contact lenses,
It is necessary to observe the state of the corneal endothelial cells before and after cataract surgery, and to observe or enlarge the corneal endothelial cells of the subject's eye conventionally, 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 directed toward the observed part from an oblique direction with respect to the eye axis, and the reflected light from the corneal surface and the image light rays of the endothelial cells are separated. Various devices have been used in which corneal endothelial cells in a test site are photographed by a television camera or the like. The present applicant has previously filed Japanese Patent Application No. 05-166132 (June 1, 1993) in order to eliminate the troublesome operation of the conventional apparatus.
(Application on day 0), it is possible to automatically perform magnified observation or magnified photographing of the corneal endothelial cells in the test part, and simultaneously measure the corneal thickness of the eye to be examined, simultaneously with the magnified observation or magnified photographing. The device was proposed. In this apparatus, when measuring the corneal thickness, two reflected lights from the corneal epithelium and the corneal endothelium are detected by one light receiving element.

[0003]

However, since the two reflected lights are strong in epithelial reflected light and weak in endothelial reflected light and have a large difference between the two, it is difficult to reliably and accurately detect these two reflected lights. There was a problem. In view of this, the present applicant has proposed an improvement in Japanese Patent Application No. 05-241986 (filed on Sep. 2, 1993) for reliably detecting corneal endothelial reflected light that is much weaker than corneal epithelial reflected light. The improvement has made it possible to reliably detect corneal endothelium reflected light with high accuracy. However, for the measurement of the corneal thickness, it is still necessary to accurately detect the epithelial reflex at the same time.

[0004] The present invention has been made in view of the above points, and it is possible to accurately and easily perform corneal endothelial focusing of a test portion and also to accurately detect epithelial reflex. It is an object of the present invention to provide a corneal cell photographing apparatus that can perform the measurement of corneal thickness easily and reliably.

[0005]

In order to achieve the above object, the present invention provides an illumination optical system for slit-illuminating the eye spherical surface of the eye to be inspected, and a lighting system for slit-illuminating the eye to be inspected based on slit illumination light illuminating the eye spherical surface. An enlarged photographing optical system for forming a magnified image on a light receiving surface of a CCD camera for observation and photographing, and at least an objective lens when a corneal endothelium image is formed on the image plane of the magnified photographing optical system in a focused state. A focus detecting light receiving element set at a position for receiving the corneal endothelium reflected light or the corneal epithelium reflected light of the slit light through, and means for moving the device body toward the eye to be examined so as to come to the corneal endothelium focused position In the corneal cell photographing apparatus, the focus detection light receiving element includes a slit light passing through an objective lens in front of the light receiving element.
The corneal endothelium reflected light with slit stop 17 long in hand direction
The light receiving element a for detection and the light receiving surface of the CCD camera
Two light receiving elements, namely, a light receiving element b for detecting corneal epithelium reflected light provided at the role position, are used.

A light receiving element b for receiving the corneal epithelium reflected light
As a light receiving element capable of detecting the moving amount of the epithelial reflected light in the moving direction, the light receiving element a for receiving the corneal endothelial reflected light receives the corneal epithelial reflected light when detecting the endothelial reflected light It is effective to configure the corneal cell photographing apparatus to calculate the corneal thickness corresponding to the epithelial reflected light receiving position on the light receiving element b. As a light receiving element b, a CC for imaging
The light receiving surface of the D camera can also be used.

[0007]

In this device, an enlarged image of the corneal endothelium of the portion to be examined is formed by the magnifying optical system based on the reflected light from the spherical surface of the eye which has been slit-illuminated by the illumination system. In this case, as shown in the optical path diagram of the corneal cell photographing apparatus in FIG. 1, the photographing system 3 is manually or automatically advanced in the direction of the eye to be examined, and
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 is slit through the objective lens 15. Epithelial reflected light of the endothelium focus detection light receiving element a
The front surface of the corneal epithelium, the illumination light that has passed through the corneal epithelium is reflected on the corneal endothelium surface behind the corneal epithelium surface on the illumination optical axis 12, and the slit-like endothelium reflected light also through the objective lens 15, Following the slit-shaped epithelial reflected light, the front surface of the endothelial focus detection light-receiving element a is moved adjacently with a small gap therebetween.

On the other hand, another CCD camera receiving of the optical axis 14 _{and second} light receiving detection endothelium focal element a and separately expanded imaging optical system
The epithelial focus detection light receiving element b provided at the conjugate position with the surface , the epithelium reflection light follows the epithelium reflection light and moves on the front surface of the epithelial focus detection light reception element b in the same manner as described above. Then, when the endothelium reflected light of the corneal reflection 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 in-focus state of the endothelium is detected, an enlarged corneal endothelial image of the test portion is detected. Is in focus on the image receiving surface 22 of the TV camera 23, the strobe discharge tube 8 of the illumination system emits light, and is in focus on the image reception surface 22 of the TV camera 23, and the strobe discharge tube 8 of the illumination system emits light and the television The magnified corneal endothelial cell image can be observed or photographed by the camera 23 via the monitor 33 (see FIG. 2). In this case, a light receiving element (for example, a phototransistor) optimal for detecting endothelial reflected light is used as the light receiving element a for detecting endothelial focus, and a light receiving element optimal for detecting epithelial reflected light is used for the light receiving element b for detecting epithelial focus. Element (eg, line sensor, PSD
, Etc.), it is possible to devise each light receiving optical path according to the application without worrying about the influence of each other, and the degree of freedom of design increases, and the light receiving function can be easily adjusted. As a result, the endothelium can be easily and accurately detected, and the position of the epithelium when the endothelium is detected can be accurately detected.

Further, as the light receiving element b for receiving the corneal epithelium reflected light, a light receiving element capable of detecting the moving amount in the moving direction of the epithelial reflected light is used. By calculating the corneal thickness corresponding to the epithelial reflected light receiving position on the light receiving element b at the time of detection, a machine which is a moving amount detecting means according to the previously filed application (Japanese Patent Application No. 05-166132). The corneal thickness can be easily measured electronically without using a typical encoder. As the light receiving element b,
The light receiving surface of a CCD camera for imaging may be used. In this case, the device becomes simple.

[0010]

An embodiment 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.

[0011] In FIG 1, an illumination system and a television camera (CCD mosquitoes based on facing the eyeball surface 2 slit illumination light irradiating the eyeball surface for illuminating the eyeball surface 2 of the eye 1 slit
Mera) 23 by consists of a larger imaging optical system so as to perform a magnification observation or enlarged photographing of the subject part, and, the enlarged image taking optical system cornea of the examined portion by a portion 14 ₁ extending in the optical path of the provided with a corneal endothelium focusing detection light receiving elements a for detecting the photographing matching position by detecting endothelial reflected light, the optical axis on the optical axis 14 ₂ branched to the optical axis 14 ₁ of the enlarged image taking optical system
14 With respect to the reflection surface of the infrared light transmitting / visible light reflecting mirror 21 disposed at an intersection of ₂ and 45 °, the image receiving surface of the TV camera
A corneal epithelium focus detection light receiving element b arranged so as to have a light receiving surface at a conjugate position with 22 detects the focus of the epithelial reflected light, and detects the epithelium reflected light by a light receiving surface long in the moving direction of the slit reflected light. It is formed so that the movement amount of the light in the movement direction can be detected.

An illumination lamp 4 used at the time of focusing of an enlarged photographing optical system as an illumination light source of a portion to be inspected of the eye spherical surface 2.
And a strobe discharge tube 8 used at the time of taking a magnified photograph of the corneal endothelial cells, the light emitted from the cornea 2 being the observation surface of the eye 1 through the projection lens 13 from the illumination optical axis 12,
The strobe discharge tube 8 is illuminated at a predetermined position on the illumination optical axis 12 and the illumination lamp 4 is illuminated via the half mirror 11 on the illumination optical axis 12 so as to irradiate at a predetermined angle from the oblique direction with respect to the eye axis. It is provided on the optical axis perpendicular to the optical axis 12. The light emitted from the illumination lamp 4 is provided with a narrow detection slit aperture 7 having a predetermined width corresponding to the slit aperture 17 on the front surface of the corneal endothelium focusing detection light receiving element a at a focus position by the condenser lens 5. The light emitted from the strobe discharge tube 8 is focused at a converging position by the condenser lens 9 and has a predetermined slightly wide slit slit 10 for photographing in order to enable photographing in a wide field of view.
And a visible light cut filter 6 is provided on the optical axis of the illumination lamp 4 before the detection slit 7.
Only the infrared light of the light of the illumination lamp 4 is reflected by the above-mentioned half mirror 11 which reflects infrared light and transmits visible light and is projected on the eyeball surface 2, while the visible light of the strobe discharge tube 8 is reflected by the half mirror 11.
And is projected onto the eyeball 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 The corneal endothelial cell image of the observed portion is received by the reflected light from
When a corneal endothelium image is formed in an in-focus state on the image receiving surface 22 of the television camera 23, an enlarged photographing optical system for magnifying observation or photographing an enlarged photograph is provided. 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 Is to be detected.

[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
14 in position on the _1, the objective lens 15 on the eyeball surface side and the objective lens 15 and the half mirror at a predetermined distance (infrared transmission and visible light reflection) 16, optical axis 14 ₁ and a predetermined 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 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 light reflectance half mirror 21 visible light imaging slit light by the strobe light out of the light beam is totally reflected, while entering the receiving surface (CCD light-receiving surface) 22 of the TV camera 23 provided on the optical axis 14 ₃ which is bent, shooting position (corneal endothelium focusing position) infrared light detection slit light extending the optical path on the optical axis 14 ₁ To are incident on the corneal endothelium focusing detection light receiving element a provided on the imaging position of the corneal reflection image light by the objective lens 15. When the corneal endothelium image is formed in focus 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 endothelial focus detection. The slit aperture 17 which is long in the longitudinal direction of the corneal reflection image in front of the light receiving element a improves the separation from the epithelial reflected light with much flare and the illumination lamp 4.
Is narrowed by the slit stop 7 at the converging position of the light emitted from the light receiving element a and enters the light receiving area of the light receiving element a.
Thus, the corneal endothelium reflected light can be reliably detected with high positional accuracy, and the imaging compatible position (focusing position) of the apparatus can be detected. In this case, the light receiving element a for corneal endothelium focus detection can easily and accurately detect the corneal endothelium focus by using a phototransistor as the optimal light receiving element for corneal endothelium focus detection.

The objective lens 15 and the magnifying lens 20
Among the image light beams enlarged by the infrared ray, the slit-shaped epithelial reflected light of infrared light passes through the half mirror 21 and forms an image on the epithelial focus detection light-receiving element b to detect epithelial focus,
It moves on the surface of the light receiving element b as the imaging system 3 advances. In this case, by using a line sensor as the epithelial focus detection light receiving element b, after the epithelial focus detection light receiving element b detects the epithelial focus, the endothelial focus detection light receiving element a performs the endothelial focus detection. The epithelial 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 the movement. Then, the imaging system 3 operates with the electric circuit shown in FIG.

Next, the operation procedure of the corneal cell photographing apparatus according to the present invention will be described with reference to the block diagram shown in FIG. 2 and the flowchart shown in FIG. First, a power supply (not shown) of the corneal cell photographing apparatus is turned on, and the optical system as the photographing system 3 is manually aligned with the eye to be inspected (centering of the pupil and the center of the television image). Drives the Z-axis to advance in the direction of the eye to be examined. While the imaging system 3 is moving forward, the light receiving element a for detecting endothelial focus detects the corneal epithelium reflected light, while the reflected light reaches the light receiving element b for detecting epithelial focus on another optical path. Subsequently, when the imaging system 3 advances and the endothelial focus detection light receiving element a receives the endothelium reflected light and the slit light reflection detection circuit 36 detects the corneal endothelium reflected light, the slit light reflection detection circuit 36 The strobe light emission control circuit 37 is activated by the signal, 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 optical system to form an enlarged image of the test portion on the light receiving surface of the television camera 23. The image signal of the magnified image of the corneal endothelial cell of the test portion from the television camera 23 is written into the frame memory 32 by the image input / output control circuit 31, and the image input / output control circuit 31
The Z-axis drive mechanism 35 stops the advance of the imaging system 3 in response to a signal from the camera, 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 first reaches the light receiving element b and moves, and the moved epithelial reflected light position on the light receiving element b is: Corneal thickness calculation circuit via slit light reflection detection circuit 36
Stored at 38, the corneal thickness calculating circuit 38 calculates the corneal thickness corresponding to the moved epithelial reflected light position on the light receiving element b, and the corneal endothelial cell enlarged image via the image input / output control circuit 31. The image is displayed on the monitor display 33 and the shooting ends. In this case, there is no movable part such as a rotary encoder, and the corneal thickness can be advantageously calculated. 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 printed out from the video printer 34. Can be attached to the chart.

In this embodiment, the corneal endothelium reflected light among the corneal reflected light is highly sensitive even with weak endothelial reflected light by using a light receiving element (for example, a phototransistor) most suitable for detecting the endothelial reflected light. In addition, the corneal epithelium reflected light can be detected by a line sensor, a PSD or a C
The use of such light receiving surface of the CD camera can be calculated can be easily detected movement amount of epithelium reflected light at the time of the endothelium reflected light detection, the cornea thickness easily and accurately by corneal thickness calculating circuit .

[0019]

According to the corneal cell photographing apparatus of the first aspect, when observing and photographing an enlarged image of the corneal endothelial cells of the eyeball of the subject, the corneal endothelial focusing of the photographing apparatus can be performed manually or automatically. Can be easily performed, and an optimal light receiving element can be used for detecting the reflected light of each of the corneal endothelium and the corneal epithelium. In addition, it is possible to devise each light receiving optical path according to the application without worrying about the influence of each other, thereby increasing the degree of freedom of design and facilitating the adjustment of the light receiving function. As a result, the corneal endothelium can be easily and accurately detected, and the position of the epithelium when the endothelium is detected can be accurately detected.

[0020]

According to the corneal cell photographing apparatus according to the second aspect, when calculating the corneal thickness together with the magnified photographing of the corneal endothelial cells, there is no need to use a measuring means such as a mechanical encoder, and the electronic measurement is performed. The corneal thickness can be easily measured by means. According to the third aspect of the present invention, the device
It can be simple.

[Brief description of the 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 endothelial imaging and corneal thickness calculation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Eyeball, 2 ... Eye spherical surface (cornea), 3 ... Photographing system, 4 ... Illumination lamp, 7 ... Detection slit aperture, 8 ... Strobe discharge tube, 10 ... Imaging slit aperture, 11 ... Infrared light reflection / visible Light transmission mirror, 12 ... illumination optical axis, 13 ... projection lens, 14 ₁ , 14 ₂ ,
14 ₃ … Enlarged optical system optical axis, 15… Objective lens, 16… Infrared light transmitting / visible light reflecting mirror, 17… Slit stop, 20… Magnifying lens, 21… Infrared light transmitting / visible light reflecting mirror, 22 ... C
CD light-receiving surface (image-receiving surface), 23 ... TV camera (CCD turtle
A) , 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 endothelial focus detection, b: Light receiving element for epithelial focus detection.

Continuation of front page (56) References JP-A-5-212002 (JP, A) JP-A-5-146409 (JP, A) JP-A-7-362 (JP, A) JP-A-7-67837 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) A61B 3/00-3/16

Claims (3)

(57) [Claims] An illumination optical system for slit-illuminating an eye spherical surface of an eye to be inspected, and an enlarged image of a portion to be inspected is formed on a light receiving surface of a CCD camera for observation and observation based on slit illumination light illuminating the eye spherical surface.
When the corneal endothelial image is formed in an in-focus state on the imaging surface of the magnifying photographic optical system, the corneal endothelium reflected light or corneal epithelium reflected light of the slit light is passed through at least the objective lens. A corneal cell imaging apparatus comprising: a focus detection light receiving element set at a position for receiving light; and means for moving the apparatus body toward the eye to be examined so as to come to a corneal endothelium focus position. The element is positioned in front of the light receiving element.
Long slit in the longitudinal direction of slit light through object lens
A cornea, comprising: a light receiving element a having an aperture 17 for detecting corneal endothelium reflected light; and a light receiving element b for detecting corneal epithelial reflected light provided at a position conjugate with a light receiving surface of a CCD camera. Cell imaging device. 2. A light receiving element b for receiving the corneal epithelium reflected light
Is a light receiving element capable of detecting the moving amount of the epithelial reflected light in the moving direction, wherein the light receiving element a for receiving the corneal endothelial reflected light receives the corneal epithelial reflected light when detecting the endothelial reflected light 2. The corneal cell photographing apparatus according to claim 1, wherein the corneal thickness is calculated corresponding to the epithelial reflected light receiving position on the light receiving element b. 3. A CCD camera for imaging as said light receiving element b.
2. The method according to claim 1, wherein the light receiving surface of the camera is used.
3. The corneal cell imaging device according to 2.