JPH08107882A - Ophthalmologic apparatus - Google Patents

Abstract

PURPOSE: To provide an ophthalmologic apparatus which can measure the thickness of each layer in a corneal tissue of an invivo eye. CONSTITUTION: A cornea C of an eye to be inspected is irradiated with illumination light emitted from an illumination light source 41 by an illumination optical system 40 and the scattered light from the cornea C of the eye to be inspected is received by an observation optical system 60 to observe an image of the eye to be inspected concerning a corneal tissue. Thus, the thickness of at least one layer of the cornea of the eye to be inspected is measured by a measuring means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmologic apparatus for observing an eye image of an eye cornea.

[0002]

2. Description of the Related Art Conventionally, there has been known an ophthalmologic instrument which measures the thickness of the entire cornea by irradiating the cornea of an eye to be inspected with illumination light emitted from an illumination light source by an illumination optical system.

[0003]

By the way, in such an ophthalmologic apparatus, a cornea formed in order of the epithelial cell layer, Bowman's membrane, corneal stroma, Descemet's membrane, and endothelial cell layer from the corneal surface side. It is not possible to measure the thickness of each layer of tissue, and as a method of measuring the thickness of each of these layers, thinly cut the eye to be inspected after death and observe and measure with a microscope. However, until now, no device has existed for measuring the thickness of each layer of corneal tissue relative to a living eye.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ophthalmologic apparatus capable of measuring the thickness of each layer of corneal tissue of a living eye.

[0005]

In order to achieve the object, the invention according to claim 1 provides an illumination optical system for irradiating the cornea of the eye to be illuminated with illumination light emitted from an illumination light source, and a cornea of the eye to be examined. The gist of the present invention is to include an observation optical system that receives scattered light from the eye and observes an image of an eye to be inspected relating to corneal tissue, and a measuring unit that measures the thickness of at least one layer of the cornea of the eye to be inspected.

[0006]

In the above-mentioned structure according to claim 1,
The illumination light emitted from the illumination light source by the illumination optical system is irradiated toward the cornea of the eye to be inspected, the scattered light from the cornea of the eye to be inspected is received by the observation optical system, and the eye image regarding the corneal tissue is observed. The thickness of at least one layer of the cornea of the eye to be examined is measured.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the ophthalmologic apparatus of the present invention will be described below with reference to FIGS.

In FIGS. 1A and 1B, an ophthalmologic apparatus S
Is an anterior segment observation optical system 1 for observing the anterior segment of the eye E.
0, an alignment index light projection optical system 20 that projects index light onto the cornea C of the eye E, a fixation target light projection optical system 26 that projects fixation target light onto the cornea C, an apparatus body (not shown), and An alignment pattern projection optical system 30 used in an alignment operation with the optometry E, a corneal tissue observation illumination optical system (illumination optical system) 40 that illuminates the cornea C with illumination light from the front,
An illumination optical system (second illumination optical system) 50 for observing corneal endothelial cells that obliquely illuminates the cornea C, and an observation and photographing optical system (observation optical system) for observing and photographing an eye image of the cornea C Equipped with 60.

The anterior ocular segment observation optical system 10 includes anterior ocular segment observation light sources 11, 11 for directly illuminating the anterior ocular segment of the eye E to be examined.
Half mirror 12, objective lens 13, half mirror 1
4, the front surface 15a is a light-shielding surface, and the back surface 15b is a total reflection surface. The optical path switching mirror 15 and the CCD camera 16 are provided, and O1 is the optical axis thereof.

The image of the anterior ocular segment of the subject's eye E illuminated by the anterior ocular segment illumination light sources 11, 11 passes through the half mirror 12 and is focused by the objective lens 13 while being focused by the half mirror 1.
It is formed on the CCD camera 16 by passing through 4. The optical path switching mirror 15 is retracted from the optical path (indicated by the chain line in FIG. 1A) when observing the anterior segment.

The alignment index light projection optical system 20 includes an alignment light source 21 for emitting infrared light, a pinhole plate 22, a half mirror 23, a dichroic mirror 24,
The projection lens 25 and the half mirror 12 are arranged on the optical path so as to match the focus with the pinhole plate 22.

The alignment index light emitted from the alignment light source 21 and passing through the pinhole plate 22 passes through the half mirror 23 and the dichroic mirror 24, and then is reflected by the half mirror 12 through the projection lens 25 to be anterior ocular segment. It is guided to the optical path of the observation optical system 10. Further, as shown in FIG. 2, the alignment index light K1 reflected by the half mirror 12 forms a bright spot image R at an intermediate position between the apex P of the cornea C and the center of curvature of the cornea C. It is reflected by the corneal surface T. Note that O2 is an eyeball optical axis that is perpendicular to the apex P of the cornea C, that is, coaxial with a line connecting the apex P and the center of curvature of the cornea C.

The light beam reflected from the cornea C is reflected by the half mirror 1.
2. It is guided to the half mirror 14 via the objective lens 13. A part of the reflected light flux guided to the half mirror 14 is reflected by the half mirror 14 and guided to an alignment detection sensor 17 such as a PSD that can detect a position.

The fixation target projection optical system 26 includes a fixation target light source 27 for emitting visible light, a pinhole plate 28, a half mirror 23, a dichroic mirror 24, a projection lens 25, and a projection lens 25.
It has a half mirror 12.

The fixation target light emitted from the fixation target light source 27 passes through the pinhole plate 28, the half mirror 23, the dichroic mirror 24, and the projection lens 25, and then the half mirror 1.
It is reflected by 2. The subject's line of sight is guided by gazing at the fixation target light reflected by the half mirror 12 as a fixation target.

The alignment pattern projection optical system 30 includes
Alignment detection sensor 17 sandwiching the half mirror 14
Pattern projection light source 31, alignment pattern plate 32, and projection lens 3 which are provided at positions facing each other.
3, half mirror 14, optical path switching mirror 15, CC
It is composed of a D camera 16.

An annular pattern is formed on the alignment pattern plate 32.
A part of the pattern forming light flux transmitted through
The image is reflected on the back surface of the and imaged on the CCD camera 16.

The CCD camera 16 outputs an image signal to the monitor device, and as shown in FIG. 3, an image E'of the anterior segment of the eye E including the pupil Pu illuminated by the anterior segment illumination light source 11 and a half image. A bright spot image R ′ by the alignment index light transmitted through the mirror 14 and an annular pattern image 42 ′ by the alignment pattern light from the alignment pattern projection optical system 21 reflected by the half mirror 14 are displayed on the screen 18 of the monitor device.
Is displayed in.

The apparatus body is swung in the up-down direction (Y direction) and the left-right direction (X direction) so that the light beam reflected by the cornea C and forming the bright spot image R'is located at the center of the annular pattern image 42 '. By doing so, alignment adjustment in the XY directions between the apparatus main body and the eye E to be inspected is performed and the eyeball optical axis O2 and the optical axis O1 of the eye E to be inspected are matched. Further, the working distance is set by moving the device body and the eye E in the front-back direction (Z direction).
In addition, the alignment adjustment here includes all adjustments in the XYZ directions.

The illumination optical system 40 for observing corneal tissue includes an illumination light source 41, a condenser lens 42, a slit plate 43, and an aperture stop 4.
4, a dichroic mirror 24, a projection lens 25, and a half mirror 12.

The condenser lens 4 is emitted from the illumination light source 41.
The visible light condensed by 2 passes through the slit plate 43, the aperture stop 44 arranged in the focal plane of the projection lens 25 in the same direction as the slit plate 43, and after being reflected by the dichroic mirror 24, The light is reflected by the half mirror 12 via the projection lens 25, guided to the cornea C along the optical axis O1, and illuminates the inside of the cornea C from the vertex P of the corneal surface T.

The illumination optical system 50 for observing corneal endothelial cells is an illumination light source for observation (second illumination light source) using a halogen lamp.
51, condenser lens 52, slit plate 53, aperture stop 5
4. It has a light projecting lens 55, and O3 is its optical axis.

Infrared light emitted from the illumination light source 51 for observation during observation is guided to the slit plate 53 while being condensed by the condenser lens 52, and the slit light flux passing through this slit plate 53 forms a slit plate 53 with the slit plate 53. Projecting lens 55 in the same direction
The projection lens 5 passes through the aperture stop 54 arranged on the focal plane.
It is guided to the cornea C by 5 and illuminated so as to traverse inward from the corneal surface T thereof.

The observation / photographing optical system 60 includes a wavelength selection filter 61, an objective lens 62, a half mirror 63, and a mask 6.
4, relay lens 65, mirror 66, variable magnification lens 67,
Focusing lens 68, optical path switching mirror 15, CCD camera 1
6 and O4 is its optical axis. The optical path switching mirror 15 is inserted into the optical path at the time of corneal tissue observation imaging and at the time of corneal endothelial cell observation imaging. Also, the mask 64
Is retracted from the optical path during corneal tissue observation and imaging.

The variable power lens 67 is set to a high magnification when observing and photographing a corneal tissue, and a low magnification when observing and photographing a corneal endothelial cell.

As shown in FIG. 4, the illumination light guided to the illumination optical system 40 for observing the corneal tissue observes the corneal epithelial cells U, the Bowman's membrane B, the corneal stroma M, and the Descemet that form the cornea C by the slit light flux K2. Scattered and reflected by each layer of the membrane D and the corneal endothelial cell N.

The light beams scattered by the respective layers U, B, M, D, N of the cornea C are transmitted through the wavelength selection filter 61, focused on the objective lens 62, transmitted through the half mirror 63, and once focused, An image of the corneal cross-section is formed on the CCD camera 16 by being reflected by the optical path switching mirror 15 through the relay lens 65, the mirror 66, the variable magnification lens 67 in the high magnification state, and the focusing lens 68, and the image on the screen 18 is shown in FIG. 5, each image of a corneal epithelial cell image U ′, a Bowman's membrane image B ′, a corneal stroma image M ′, a Descemet's membrane image D ′, and a corneal endothelial cell image N ′ in the cross-sectional direction of the cornea C is displayed. .

From each image U ', B', M ', D', N'formed on the CCD camera 16, the curvature of the cornea C,
Depending on the image magnification, the refractive index, the angle of the optical axis O3, the angle of the optical axis O1 (when the optical axis O1 is perpendicular to the apex of the cornea), etc., the image processing device and the arithmetic device The thickness F1, F2, F3, F4, F5 of each layer is measured.

The image processing apparatus functions as a measuring means and measures the thickness by calculation. As another measuring means, as shown in FIG. 6, the cornea C from the cornea C received by the line sensor 69 is used. Based on the scattered light, the boundary portion of each image U ', B', M ', D', N'is detected from each peak value,
The intervals of this peak value are the thicknesses F1, F2, F3, F of each layer.
It is also possible to calculate by judging as 4, F5.

As another measuring means, the screen 1
It is conceivable to display a scale corresponding to the display magnification on the display 8 on a one-to-one basis. However, when the scale is displayed, the thickness measurement itself is a visual measurement. Further, for the measurement, not only the calculation of all the layers but also individual or combination measurement such as observing at a higher magnification and measuring only the thickness of the endothelial cell N is possible by selection or setting.

The slit light beam K3 guided to the corneal endothelial cell observing illumination optical system 50 shows how the slit light beam K3 is reflected by the cornea C, as shown in FIG. Part of the slit light beam K3 is first reflected on the corneal surface T which is the boundary surface between the air and the cornea C. The amount of the reflected light flux k from the corneal surface T is the largest. The light quantity of the reflected light flux n from the corneal endothelial cells N is relatively small, and the light quantity of the reflected light flux m from the corneal stroma M is the smallest.

The reflected light beam from the cornea C passes through the wavelength selection filter 61, is condensed by the objective lens 62, and is guided to the half mirror 63. The reflected light flux that has passed through the half mirror 63 forms an image once at the position of the mask 64, and
By 4, the extra reflected light flux other than that for forming a corneal endothelial cell image is blocked. Further, the reflected light flux passing through the mask 64 is reflected by the mirror 66 via the relay lens 65,
It is reflected by the optical path switching mirror 15 through the variable power lens 67 and the focusing lens 68, and an image is formed on the CCD camera 16.

8, a corneal endothelial cell image N ″ is displayed on the screen 18. In FIG. 8, a broken line 71 represents a light flux k reflected from the corneal surface T if it is not shielded by the mask 64. Is an optical image formed by
Reference numeral 2 is an optical image by the reflected light beam m from the corneal substance M. The shaded portion in FIG. 8 is the portion shielded by the mask 64.

On the other hand, the reflected light beam reflected by the half mirror 63 is guided to the alignment detecting line sensor 69 located at a position conjugate with the mask 64 at the image forming position.

The line sensor 69 is arranged as shown in FIG. 9B with respect to the cross-sectional direction of the cornea C, and the intensity distribution of the reflected light flux is as shown in FIG. 9A. . In FIG. 9A, reference numeral P1 is a peak portion due to the reflected light flux k reflected on the corneal surface T, and P2 is a peak portion due to the reflected light flux n reflected at the corneal endothelial cell N. The peak portion P1 corresponds to the optical image 71, and the peak portion P1
2 corresponds to the optical image 72. Known means are used to detect the peak portions P1 and P2 and to detect the centers of the peak portions P1 and P2. On the other hand, the line sensor 69 outputs a focus determination signal to the control circuit 73.

The control circuit 73 stores the signals of the peak portions P1 and P2 and performs arithmetic processing to determine the center address p of the peak portion P2 of the reflected light flux n at the time of corneal endothelial cell observation and photographing, and at the same time, this center address. It judges whether p coincides with the predetermined address Q of the line sensor 69, detects the alignment between the eye E to be inspected and the apparatus main body, and controls each optical member of the drive system.

That is, the control circuit 73 uses the line sensor 69.
When the position detection value of the light flux imaged on the image falls within the allowable alignment range in the vertical and horizontal directions, the central address p of the reflected light flux n from the corneal endothelial cells N coincides with the predetermined address Q, and at the time of this coincidence, the mask 64 and the optical path. The switching mirror 15 is inserted in the optical path. The scattered light shown in FIG. 4 is used at the time of corneal tissue observation and imaging. At this time, the thickness of each layer in the cross-sectional direction can be calculated based on the amount of light on the line sensor 69.

In the above structure, first, each light source 1
Rough adjustment of alignment is performed while illuminating 1, 21, 51 and checking the display on the screen 18.

In the judgment circuit 73, the position detection value by the alignment detection sensor 17 falls within the alignment allowable range in the XY directions, and the central address p of the reflected light beam k from the corneal surface T is Z of the line sensor 69 by the alignment operation.
When the predetermined address Q, which is the directional allowable range, is entered (matched), the information about the selection mode of either the corneal tissue observation mode or the corneal endothelial cell observation mode and the output of the line sensor 69 are output to the control circuit 74.

When the corneal tissue observation mode is selected, the control circuit 74 turns off the light sources 11 and 51 and retracts the mask 64 from the optical path, and also the illumination light source 41.
After turning on and setting the variable power lens 67 to a high magnification, the optical path switching mirror 15 is inserted into the optical path.

When the optical path switching mirror 15 is inserted into the optical path, the display state of the screen 18 is switched from the anterior ocular segment display state shown in FIG. 3 to the corneal tissue display state in the corneal cross-sectional direction shown in FIG.

Then, the alignment detection sensor 1 is further adjusted by finely adjusting the alignment in the corneal tissue display state.
7 and the output of the line sensor 69, and when the alignment in the XYZ directions is within the allowable range, the control circuit 7
An imaging execution signal is output from 4, and the images formed on the CCD camera 16, that is, each image U ′, B ′, M ′, D ′, N ′ as a corneal tissue image displayed on the screen 18 are displayed. To be photographed.

On the other hand, when the corneal endothelial cell observation mode is selected, the control circuit 74 turns off the light source 11 and moves the variable power lens 67 along the optical axis O4 to reduce the magnification, and Optical path switching mirror 15 and mask 6
4 is inserted into each optical path.

When the optical path switching mirror 15 is inserted into the optical path, the display state of the screen 18 is switched from the anterior ocular segment display state shown in FIG. 3 to the corneal endothelial cell display state shown in FIG.

Then, in this corneal endothelial cell display state, fine adjustment of alignment is further performed, and XY is judged based on the outputs of the alignment detection sensor 17 and the line sensor 69.
When the alignment in the Z direction is within the allowable range, the control circuit 74 outputs a photographing execution signal, and the CCD camera 16
The image formed on the screen, that is, the corneal endothelial cell image N ″ displayed on the screen 18 is captured.

The image N ″ of the corneal endothelial cells after photographing is used for the unit area (for example, 0.1 mm × 0.1 mm) in addition to the diagnosis of the state thereof.
The number of cells per mm) is confirmed.

By the way, in the above-mentioned embodiment, the measurement / photographing is carried out by visible light, but it may be carried out by infrared light.
Further, the optical axis of the illumination optical system 40 for observing corneal tissue is coaxial with the optical axis O2 of the eyeball (in the alignment completed state).
However, the light beam emitted from the illumination light source 41 is configured to illuminate the subject's eye E at an angle, and the optical axis at that time is the observation optical axis with respect to the eyeball optical axis O2. The angle is not particularly limited as long as it is different from O4.

As described above, the illumination optical system 4 for observing corneal tissue is used.
Since the optical axis of 0 and the optical axis of the observation optical system 60 are not symmetrical with respect to the optical axis O2 of the eyeball, the light flux emitted from the illumination light source 41 and reflected on the corneal surface T of the eye E to be examined has a high light amount. Is not guided to the observation optical system 60, the corneal tissue can be observed based on the scattered light in the cross-sectional direction of the cornea having a low light amount.

Therefore, for example, in the case of myopic surgery in which the disease in the cross-sectional direction is detected, the thickness of each layer of the cornea C which is different depending on the individual difference and the disease is measured or confirmed, or the corneal surface is corrected by shaving the corneal surface with a laser knife. Checking the power setting / change of the laser knife and the amount of shaving before and during that
It is possible to observe and photograph each layer in the cross-sectional direction, which could not be achieved in the living eye, such as measurement and inspection of cross-sectional thickness after myopia surgery including myopia surgery in which the corneal surface is damaged and corrected by a scalpel. .

[0050]

As described above, in the ophthalmologic apparatus of the present invention, the illumination optical system that illuminates the illumination light emitted from the illumination light source toward the cornea of the eye to be inspected, and the scattered light from the cornea of the eye to be inspected. By including an observation optical system that receives light and observes an image of the eye to be inspected relating to the corneal tissue, and a measuring unit that measures the thickness of at least one layer of the cornea of the eye to be inspected, The thickness of each layer can be measured.

[Brief description of drawings]

1A and 1B show an embodiment of an ophthalmologic apparatus of the present invention, FIG. 1A is an explanatory diagram of a main optical system, and FIG. 1B is an explanatory diagram of a corneal tissue observation illumination optical system.

FIG. 2 is likewise an explanatory view showing a cornea reflection state of index light.

FIG. 3 is likewise a front view of the screen in an anterior segment observation state.

FIG. 4 is an explanatory diagram showing a reflection state of a slit light beam on the cornea during corneal tissue observation and imaging.

FIG. 5 is likewise a front view of a screen in a corneal tissue observation and imaging state.

FIG. 6 is a graph showing the amount of light received by the line sensor during corneal tissue observation and imaging.

FIG. 7 is an explanatory view showing a reflection state of a slit light beam on the cornea during corneal endothelial cell observation and photography.

FIG. 8 is likewise a front view of the screen in a state of photographing and observing corneal endothelial cells.

9A is a graph showing the amount of light received by the line sensor during fine alignment during corneal endothelial cell observation imaging, and FIG. 9B is an explanatory view showing the light receiving state of the eye image on the line sensor at that time. Is.

[Explanation of symbols]

 E ... Eye to be inspected C ... Corneal 40 ... Illumination optical system for corneal tissue observation (illumination optical system) 41 ... Illumination light source 60 ... Observation optical system (observation optical system)

Claims (5)

[Claims] 1. An illumination optical system for irradiating the cornea of an eye to be inspected with illumination light emitted from an illumination light source, and an observation optical system for receiving scattered light from the cornea of the eye to observe an eye image of the corneal tissue. An ophthalmologic apparatus comprising: a measuring means for measuring the thickness of at least one layer of the cornea of the eye to be examined. 2. The optical axis of the illumination optical system and the optical axis of the observation optical system are arranged at an asymmetric angle about an axis perpendicular to the apex of the cornea. The described ophthalmic device. 3. The ophthalmologic apparatus according to claim 2, wherein an optical axis of the illumination optical system is coaxial with an axis perpendicular to the apex of the cornea. 4. A second illumination optical system for irradiating the cornea of the eye to be illuminated with illumination light emitted from a second illumination light source, and a reflected light from the cornea of the eye to be inspected to receive a corneal endothelial cell image. The ophthalmologic apparatus according to claim 1, further comprising a corneal endothelial cell observation / photographing optical system for observing and photographing the optometry image. 5. The optical axis of the second illumination optical system and the optical axis of the observation optical system are arranged at a target angle around an axis perpendicular to the apex of the cornea. The ophthalmic device according to.