JP2002017678A - Corneal cell photographing instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a corneal cell photographing instrument capable of obtaining a clear image of even a tissue in corneal stroma by scanning the cornea by slit illumination light. SOLUTION: The instrument is provided with an illumination optical system 4 having a plurality of first slits 19a to illuminate the anterior ocular segment of an examined eye E diagonally from the front by slit illumination light passing through the first slits 19a, and a photographing optical system 5 having a plurality of second slits 19b to photograph the light, reflected by the anterior ocular segment, of the illumination light through the second slits 19b. The first and second slits 19a and 19b are formed at the positions on a rotary slit plate 19 so as to be point symmetrical with respect to the center of the rotation. The slits are positioned so that the intervals between the adjacent slits may be larger than a dimension corresponding to the intervals between the mirror surface reflection light on the surface of a lacrimal layer of the examined eye and the mirror surface reflection light from a corneal endothelium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a corneal cell photographing apparatus. More specifically, the present invention relates to a corneal cell photographing apparatus for observing and photographing corneal cells of an eye to be examined by a specular method. The specular imaging apparatus is an apparatus that irradiates illumination light obliquely with respect to the optical axis of the eye to be examined, receives specularly reflected light from the cornea thereof obliquely, and observes and photographs this image.

[0002]

2. Description of the Related Art FIG. 10 schematically shows a cross section of a cornea C. As shown in FIG. Symbol T is a tear film. The symbol U indicates the epithelium, the symbol J indicates the substantial part, and the symbol I indicates the endothelium. Conventionally, there is no known device for clearly observing and photographing cells in the parenchyma J existing between the epithelium U and the endothelium I of the cornea. This is because the parenchyma J has not received much attention in various medical fields including ophthalmology.

Recently, however, LA has been used to correct diopter.
SIK (Lasik) surgery is being actively performed. In the LASIK operation, the cornea C of the eye to be examined is placed in the parenchyma J
Then, the exposed substantial part is ground by a laser beam or the like to thin the cornea C. Then, the cornea C, which has been bisected, is returned to the original state, and the restoration and integration are awaited. In this case, it is necessary to observe the cornea after the operation and monitor the restoration state of the bisected cornea. That is, the bisected portion D of the parenchyma of the cornea (FIG. 10) must be explored and observed.

[0004] For this purpose, a device is required which clearly separates the image showing the state of each layer from the images of other layers while moving the observation point in the thickness direction of the cornea. This is because the parenchymal part has cells which are not arranged in layers like endothelial cells and epithelial cells and have an irregular shape in the corneal thickness direction.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to observe and photograph clear images of not only the endothelium and epithelium of the eye to be examined but also each layer of the substantial part. It is an object of the present invention to provide a corneal cell photographing apparatus that can perform the method.

[0006]

The corneal cell photographing apparatus of the present invention has a plurality of movable first slits arranged in front of the eye to be examined by slit illumination light passing through the first slits. An illumination optical system for illuminating the eye from obliquely forward, has a plurality of second slits that are movable and aligned, and reflects the reflected light of the slit illumination light reflected by the anterior eye on the second. An imaging optical system for imaging through a slit, wherein the second slit is configured to move in synchronization with the movement direction of the reflected light accompanying the movement of the first slit, and an adjacent slit The distance between them is set to be equal to or larger than the distance between the specular reflected light from the tear film surface of the eye to be examined and the specular reflected light from the corneal endothelium at the position where the second slit is provided.

Therefore, the slit illumination light moves on the cornea of the eye to be examined, and the reflected light moving can be observed and photographed. Therefore, a wide range of the cornea can be observed and photographed even with extremely narrow slit illumination light. Moreover, since it is possible to use narrow slit illumination light, it is possible to separate the reflected light from the observation target site from the reflected light from other layers. As a result, a clear image of each layer of the cornea including the epithelium can be taken. In addition, since the interval between the slits transmitting the reflected light is limited as described above, it does not overlap with the reflected light transmitted through the adjacent slit, so that a clearer image can be obtained. This means that an image of the stromal portion of the cornea, which does not originally have a clear layered shape, can be obtained in a clear form.

[0008] In the corneal cell photographing apparatus in which the first slit and the second slit are formed in the same slit member, and the slit member is configured to rotate, the first slit and the second slit are formed. It is easy to move the second slit synchronously. Further, it is preferable because the configuration of the device is simplified.

Another corneal cell photographing apparatus of the present invention has a plurality of movable first slits, and the anterior segment of the eye to be examined is moved by slit illumination light passing through the first slits. An illumination optical system for illuminating diagonally from the front,
Having a plurality of aligned second slits that are movable,
An imaging optical system for imaging the reflected light reflected by the anterior eye of the slit illumination light through a second slit, wherein the second slit moves the reflected light accompanying the movement of the first slit. A field stop that is configured to move in synchronization with the direction, and is arranged in the vicinity of the first slit, and arranged so that illumination light can be transmitted only to the single first slit that moves. I have.

According to such a configuration, not only can a clear image of each layer of the cornea be taken, but also the slits adjacent to the slit transmitting the illumination light do not transmit the illumination light, so that the images do not overlap. Therefore, a clearer image can be obtained, and an image of the corneal stromal portion can be obtained in a clearer form.

Further, in addition to the field stop of the first slit, it is arranged so that the reflected light from the eye to be examined can be transmitted only to the single moving second slit in proximity to the second slit. In a corneal cell photographing apparatus provided with a field stop, scattered light due to light from other slits can be greatly restricted, so that a clearer image can be obtained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A corneal cell photographing apparatus according to the present invention will be described based on an embodiment shown in the accompanying drawings.

FIG. 1 is a perspective view showing an embodiment of the corneal cell photographing apparatus according to the present invention. FIG. 2 is a plan view of the corneal cell photographing apparatus of FIG. FIG. 3 is a rear view of the corneal cell photographing apparatus of FIG. 1 (a view as seen from the rear of the apparatus toward the subject's eye). FIG. 4 is a rear view showing an example of a slit plate in the corneal cell photographing apparatus of FIG. 1 (a diagram viewed from the rear of the slit plate toward the subject's eye).

The corneal cell photographing apparatus 1 shown in FIGS. 1 to 3 has a machine frame which can be moved in the Z direction which moves forward and backward toward the eye E, and in the X direction and the Y direction which are perpendicular to the Z direction and perpendicular to each other. (Not shown).

The photographing system 2 includes an illumination optical system 4 for illuminating the anterior eye portion of the eye E with diagonal light from the oblique front thereof and the slit light reflected on the surface of the anterior eye portion of the eye E. A photographing optical system 5 for photographing, and an alignment index light for photographing optical axis alignment (alignment) directed toward the anterior segment of the eye E to be photographed from the front, and an image of the corneal reflected light. An alignment optical system 6, a focusing optical system 7 for making the focal point of the imaging optical system 5 coincide with the corneal endothelium, which is the imaging site, and an optical axis of the illumination optical system 4 and an optical axis of the imaging optical system 5 intersected And a rotating slit plate 9.

The illumination optical system 4 has a strobe discharge tube 8 as a light source for illuminating the anterior segment. The visible light from the strobe discharge tube 8 is passed through a slit 19 formed in the slit plate 9.
, And the 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 optical path of the illumination optical system 4 in order to make the optical path of a focusing optical system to be described later identical from the optical path of the illumination optical system 4. The cold mirror 11 reflects illumination light, which is visible light, and transmits infrared detection light, which will be described later, for focus detection. Reference numeral 27 in FIG. 1 denotes a continuous observation lamp that continuously emits illumination light to continuously observe an image of a corneal cell.

The photographing optical system 5 has a television camera 12 for photographing corneal cells. The slit light reflected by the cornea of the subject's eye E passes through the photographing lens 13, the mirror 14, and the imaging lens 15, and then passes through the television camera 1.
It is led to 2. In the present embodiment, the optical path of the photographing optical system 5 is the same as the optical path of the focusing optical system 7 described later halfway. Cold mirror 1 for splitting the optical path for this purpose
6 are interposed. The cold mirror 16 reflects illumination light that is visible light and transmits focus detection light that is infrared light.

The alignment optical system 6 has a light emitting diode 17 as a light source of the alignment index light and a television camera 18. The near-infrared light from the light emitting diode 17 is applied to the anterior segment of the eye E through the half mirror 22 from the front. Further, a bright point (Purkinje image), which is a reflection image of the alignment index light on the cornea of the eye E, is transmitted to the television camera 18 through the half mirror 22. By moving the machine frame in the X and Y directions based on the Purkinje image, the photographing optical axis is made to coincide with the corneal vertex.

The slit plate 9 is rotated by a motor 20 and has a plurality of slits 19 formed on a circumference having 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 a first slit) 19a is reflected by the anterior segment of the eye E to be inspected, and the first slit 19a with the rotation center 3 of the slit plate 9 interposed therebetween. The illumination optical system 4 and the photographing optical system 5 are arranged so as to pass through another slit (hereinafter, referred to as a second slit) 19b located in a direction of 180 ° to the television camera 12. Further, the slit illumination light moves on the anterior segment of the eye E as the first slit 19 a moves by the rotation of the slit plate 9. Then, the slit reflected light in the anterior segment 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. The illumination optical system 4 including the relay lens 25 and the mirror 14 and the optical devices of the photographing optical system 5 include the relay lens 25 and the mirror 14 so that the illumination light and the reflected light can pass through the slits 19a and 19b moving in synchronization in this manner. The arrangement has been made. Further, it is preferable that both slits 19a and 19b are formed to have the same width.

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 focusing lamp 21 reaches the subject's eye E along the optical axis 4 a of the illumination optical system 4, is reflected by the anterior eye, and is reflected by the optical axis 5 a of the imaging optical system 5. Along the way, it reaches the position sensor 23 and receives light.

That is, the intersection point (the above-mentioned focal point) between the optical axis 4a of the illumination optical system 4 and the optical axis 5a of the photographing optical system 5 is the eye E to be examined.
The position sensor 23 detects the reflected light of the in-focus detection light when the camera is located at the imaging site. At that time, the slit 19
Illumination light and reflected light pass through a and 19b, respectively. That is, the focal point of the photographing optical system 5 is set to the above-mentioned focal point, and both slits 19a and 19b are located at conjugate positions with respect to the focal point. Then, by moving the imaging system 2 in the Z direction in FIG. 1, the focal point is aligned with the imaging site of the eye E to be inspected. This alignment is called focusing.

The position sensor is a beam splitter 23
c, 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 light receiving devices 23a and 23b have slits. Each of the light receiving devices 23a and 23b has light receiving optics for making the magnification of an image to be received, the width of slit light, the wavelength of received light, the polarization, and the like different from each other. By doing so, it becomes possible to easily focus on the test site having different properties. For example, the first light receiving device 23a capable of capturing the position of the endothelium of the cornea and the second light receiving device 23b capable of distinguishing and capturing the position of the tear film and the position of the epithelial cell are combined. As a result, it is possible to clearly observe and photograph an image of epithelial cells, which has been difficult in the past.

In FIG. 1, reference numeral 29 denotes a fixation target light source for keeping the orientation of the eye E fixed by causing the eye E to fixate.

With the configuration described above, the cornea of the eye E is scanned by 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, by forming a range in which the slits 19 are formed at equal intervals in the slit plate 9 so as to be point-symmetric with respect to the rotation center 3, the above scanning is repeated in a very short time. Therefore, corneal cells can be observed as moving images. The slits need not be formed at regular intervals, and need not be formed over the entire circumference.
However, by forming a plurality of slit areas symmetrically with respect to points, it is possible to repeatedly scan even slit light that illuminates an extremely narrow range. As a result, the problem caused by the small amount of illumination light can be solved.
Also, the rotation direction of the slit plate 9 may be only one direction,
Further, the reciprocating rotation may be performed at a predetermined stroke.

As a result, it is possible to use slit illumination light having a width narrow enough to completely separate the reflected light from the surface of the tear film (about 10 μm or less) on the corneal surface and the reflected light from the corneal epithelium. Becomes 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 passing through the slit 19 is converted into a slit having a width of about 10 microns on the cornea by a lens system. Reduce so that it becomes illumination light. This reflected light is also enlarged by the lens system of the photographing optical system 5.

Next, the distance between the adjacent first slits 19a in the illumination optical system 4 and the distance between the adjacent second slits 19b in the photographing optical system 5 will be described. First, FIG. 5 is a diagram illustrating a slit plate and a light beam in a corneal cell imaging device as a comparative example.

As shown in FIG. 5, if the distance d1 between the adjacent first slits 191a, 192a, and 193a is too small, the illumination light from a plurality of adjacent slits (these illumination light is a part of the cornea to be illuminated on the cornea to be examined) Are different from each other). This interval is the second slit 191
The same applies to b, 192b, and 193b. This is because the first and second slits are moved synchronously so as to correspond one-to-one. Each slit illumination light L1, L2, L3 is reflected at each layer of the cornea C, and thus has a width as shown in the figure. Therefore, of the reflected light by the slit illumination light L2, the second slit 192b transmitting the reflected light R2F from the observation region F, that is, the focused region F, that is, the second slit corresponding to one first slit 192a. There is a possibility that the reflected lights R1 and R3 by the slit illumination lights L1 and L3 from the other first slits 191a and 193a may also pass through the 192b. Then, the image of the observation site F overlaps the image of another site. As a result, it is difficult to obtain a clear image especially when photographing the substantial portion J.

Therefore, as shown in FIG. 6, in this embodiment, the distance d1 between the adjacent slits is set to the specular reflection light on the corneal surface (the tear film surface) and the specular reflection from the corneal endothelium at the second slit position. Dimensions corresponding to the distance da from the light,
Or larger dimensions. By doing so, as shown in the figure, the reflected light transmitted through one second slit 192b does not overlap with the reflected light from another portion. Therefore, as shown in FIG.
Of the illumination light L2 transmitted through the light source 2a, substantially the observation site C
Only the reflected light R2F reflected by the light source can be transmitted to obtain a clear image.

Further, as shown in FIGS. 1 to 3 and 7, a field stop 28 may be provided at a position close to the first slit 19a and at a position close to the second slit 19b.

This field stop 28 is shown in FIG.
FIG. 8 is a rear view (viewed from the rear of the mask toward the eye to be inspected) showing an example of a mask for an observation visual field in the corneal cell imaging apparatus of FIG. 1. The field stop 28 is a slit plate 9
The observation field 28a is formed as an open mask 28 with the optical axis of the illumination optical system 4 and the optical axis of the photographing optical system 5 at the center. The width of the observation visual field 28a is made substantially the same as the slit length, and the length in the slit movement direction (dimension in the slit scanning direction, which is the vertical dimension M in the drawing) is made slightly smaller than the interval d1 of the slits 19 formed in the slit plate 9. So that only one reflection slit light R can pass at a time.

By doing so, as shown in FIG.
Slit illumination light L transmitted through one first slit 192a
2 reaches the subject's eye E, and the observation site F in the reflected light
The reflected light R2F from is transmitted through the corresponding second slit 192b. That is, other first slits 191a, 19
The illumination light from 3a is blocked by the mask 28. As a result, a clear image of the substantial portion J can be obtained without overlapping the images.

The dimension M of the observation field 28a in the slit scanning direction in the figure is determined, for example, as follows. FIG.
Referring to, let T be the thickness of the cornea C (including the tear film),
The refractive index of the atmosphere is N1, the refractive index of the cornea C is N2,
The incident angle of the slit illumination light to the cornea is θ1, and the distance d between the reflected light on the corneal surface (the tear film surface) and the reflected light on the endothelium
a is: da = 2T × (N1 / N2) × sin θ1 × co
sθ1.

In the present invention, the mask 28 may be provided only on the first slit 19a side, but in the present embodiment, it is additionally provided on the second slit 19b as described above. In this way, various types of scattered light can be blocked.

As described above, when the mask 28 is provided, even if the interval between the slits is narrower than the specified value as shown in FIG. 9, the illumination light from the adjacent slit is blocked. The image of the observation site F does not overlap the image of another site.

In the above embodiment, the non-contact type corneal cell photographing apparatus has been described as an example. However, the present invention is not limited to a non-contact type corneal cell imaging device, and is of course applicable to a contact type corneal cell imaging device. The configuration of the slit and the field stop of the present invention does not change regardless of whether it is a non-contact type or a contact type.

As is well known, a contact type corneal cell photographing apparatus is provided with an objective lens (in FIG. 1, an integrated lens of the illumination lens 10 and the photographing lens 13 corresponds to the surface of the eye) to be examined. A cone lens to be brought into contact with is provided. Then, the machine frame in which the cone lens and the objective lens are integrally attached is pressed against the subject's eye by a weak urging force. It is designed to be able to move according to the displacement of the eye to be examined. For this purpose, in the illumination optical system and the photographing optical system, the light flux reaching the objective lens becomes parallel light. It is a so-called afocal system. For example, referring to FIGS. 1 and 2, an afocal system is provided between the relay lens 25 and the objective lens. The present invention can be easily applied to such a known contact type corneal cell imaging apparatus.

[0037]

According to the corneal cell photographing apparatus of the present invention, a clear image of each layer including the substantial part of the cornea can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a corneal cell photographing apparatus of the present invention.

FIG. 2 is a plan view of the corneal cell photographing apparatus of FIG.

FIG. 3 is a rear view of the corneal cell photographing apparatus of FIG. 1;

FIG. 4 is a rear view showing an example of a slit plate in the corneal cell photographing apparatus of FIG. 1;

FIG. 5 is a diagram illustrating a slit plate and a light beam in a corneal cell imaging apparatus as a comparative example.

FIG. 6 is a diagram illustrating a slit plate and a light beam in the corneal cell imaging apparatus of FIG. 1;

FIG. 7 is a diagram illustrating a slit plate and a light beam in another embodiment of the corneal cell imaging apparatus of the present invention.

FIG. 8 is a rear view showing an example of a mask for an observation visual field in the corneal cell photographing apparatus of FIG. 1;

FIG. 9 is a diagram illustrating a slit plate and a light beam in still another embodiment of the corneal cell imaging apparatus of the present invention.

FIG. 10 is a cross-sectional view schematically showing a cross section of a cornea of an eye to be examined.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Corneal cell imaging apparatus 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 TV camera 19 Slit 19a, 191a, 192a, 193a First slit 19b, 191b, 192b, 193b 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 field 29 Fixation target light source C Cornea E Eye to be examined F Observation Site I Endothelium J Parenchyma L1, L2, L3 Slit illumination R, R1, R2F, R3 Reflected light U Epithelium

Claims (4)

[Claims] 1. An illumination optical system comprising: a plurality of movable first slits which are movable; and an illumination optical system for illuminating an anterior eye of an eye to be examined from obliquely forward with slit illumination light passing through the first slits. A plurality of aligned second slits that are movable;
An imaging optical system for imaging the reflected light reflected by the anterior eye of the slit illumination light through a second slit, wherein the second slit moves the reflected light accompanying the movement of the first slit. It is configured to move in synchronization with the direction, the interval between adjacent slits, at the second slit arrangement position, the specular reflected light of the tear film surface of the eye to be examined and the specular reflected light from the corneal endothelium A corneal cell photographing apparatus having a size equal to or larger than the distance corresponding to the distance between the corneal cells. 2. The corneal cell photographing apparatus according to claim 1, wherein the first slit and the second slit are formed in the same slit member, and the slit member is configured to rotate. 3. Illumination optics having a plurality of movable first slits which are movable and for illuminating an anterior eye portion of an eye to be examined from obliquely forward with slit illumination light passing through the first slits. A plurality of aligned second slits that are movable;
An imaging optical system for imaging the reflected light reflected by the anterior eye of the slit illumination light through a second slit, wherein the second slit moves the reflected light accompanying the movement of the first slit. A field stop that is configured to move in synchronization with the direction, and that is disposed in the vicinity of the first slit and that is arranged so that illumination light can be transmitted only to a single first slit that moves. Corneal cell imaging device. 4. A field stop arranged in proximity to said second slit so that only a single moving second slit can transmit reflected light from an eye to be examined. Corneal cell imaging device.