JPH0330366B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ophthalmological apparatus, such as an ophthalmic surgical microscope, which has a function of measuring the corneal shape of an eye to be examined and/or a function of measuring the refractive power of the eye to be examined.

The eye forms a precise optical system, and appropriate measures are taken to restore its function in the event of any disease. Particularly when some kind of surgery is performed on the eyeball, it is important to reconstruct its function and shape, and recovery of the eye's refractive power is an important factor that determines the success or failure of the surgery. In recent years, with the aging of the population, anterior segment surgery, especially cataract surgery, has become more common, but it is important to accurately understand changes in corneal shape after surgery and expected changes in eye refractive power after intraocular lens insertion. This is an essential thing to do during surgery. For this reason, it is necessary to constantly measure changes in the shape of the cornea and the refractive power of the eye, not only after the surgery, but also during the surgery, in order to know whether or not the restoration process is normal. Traditionally, the surgical microscopes used to perform this type of eye surgery only have the observation and photography function during surgery, and a completely different method is required to measure the corneal shape and refractive state of the eye during surgery. The procedure must be replaced with a new measuring device, which requires a long interruption of the surgery, requires considerable effort, and the layout makes it practically impossible to perform the procedure using a full-scale measuring device.

Also, when observing the peripheral area of the anterior segment of the subject's eye during surgery, it would be helpful for the examiner to be able to measure the eye refractive power or corneal shape through the central area of the anterior segment of the subject's eye without moving the entire device. It's very convenient.

Similarly, when observing the central region of the anterior segment of the subject's eye, it would be convenient if the eye refractive power or corneal shape could be measured via the peripheral region of the anterior segment of the subject's eye without moving the entire apparatus.

In view of the above, an object of the present invention is to provide an ophthalmologic apparatus that eliminates the drawbacks of the conventional example.

Examples of the present invention will be described below.

In FIG. 1, light from a lamp 1 for observing the anterior segment of the eye to be examined passes through a half mirror 2, a condenser lens 3, a prism 4 with a lens, and an objective lens 5 to illuminate the eye Ep. The light reflected from the anterior segment of the subject's eye is passed through an objective lens 5, a beam splitter 13,
14 and enters the relay lens groups 6, 7, 8,
After being reflected by the flip-up mirror 9, it is observed by the viewing eye E via the fixed mirror 10 and the eyepiece lens 11.

When photographing the anterior segment of the subject's eye, the strobe 113 emits light and illuminates the anterior segment through the objective lens 5, and the light from the anterior segment passes through the objective lens 5, beam splitters 13, 14, relay lens group 6, The image passes through mirrors 7 and 8, passes under the mirror 9 that has been flipped up, and is imprinted on a film or other image recording means 12.

Here, the optical system for measuring eye refractive power will be explained.

Light from a light source 20 for measuring eye refractive power passes through a condenser lens 19 and illuminates the projection chart 18 . The projection chart 18 has slits 18a, 18 having at least three directions as shown in FIG.
b, 18c, and the light passing through each slit is
Projection lens 29, ring-shaped aperture 2 shown in FIG.
8a aperture diaphragm 28, relay lens 27,
17, the light passes through the perforated mirror 16, the relay lens 15, the beam splitters 14 and 13, and the objective lens 5, and reaches the eye Ep to be examined, and projects each slit image light onto the fundus.

The light reflected from the fundus passes through the objective lens 5, beam splitters 13 and 14 again, and reaches the relay lens 1.
5. Hole of perforated mirror 16, relay lens 2
1, 37, an aperture stop 38 having an aperture 38a as shown in FIG. 4, and a projection lens 39 before reaching the light receiving chart 22. The light receiving chart 22 is conjugate with the projection chart 18 with respect to the perforated mirror 16, and is connected to the three slits 18a, 18 of the projection chart 18.
There are three slits 22a, 22b, 22c as shown in FIG.
Light receiving elements 23a, 23b, placed at the rear of c.
23c. The best focusing plane of each slit (at this time, the received light output is maximum) is found by moving the lens systems La and Lb along the optical axis, and the surface of the subject's eye is determined from the amount of movement from the initial position.
The refractive power of Ep is calculated. Here, the refractive power of the eye to be examined corresponding to each slit direction is calculated and the spherical refractive power S, astigmatic degree C, and astigmatic axis angle A are calculated.
Calculate.

Next, the corneal shape measuring optical system will be explained. The light from the light sources 34a, 34b,..., 34i, 34j is transmitted through the corresponding light guides 33a, 33b,..., 3
3i, 33j, and light sources 32a, 3 at the other end.
2b, . . . , 32i, 32j to form a discrete ring-shaped light source, which is projected onto the cornea of the subject's eye Ep to form a corneal reflection image. The light reflected by the cornea emerges as if from a corneal reflected image, and is imaged onto a two-dimensional solid-state image sensor 36 by the objective lens 5, beam splitter 13, and projection lens 35.

If the light sources 32a, 32b,..., 32j are arranged concentrically around the objective lens 5 as shown in FIG. is projected. The curve of the cornea is calculated from this projected image. In other words, a ring-shaped projection chart is projected onto the eye to be examined, and if the eye to be examined does not have astigmatism, the corneal reflection image will also be a perfect circle, but if there is astigmatism, it will become an ellipse, and if there is irregular astigmatism, distortion will be added to this image. The shape of the corneal reflection image is determined using a solid-state image sensor, and the corneal curvature R, degree of astigmatism D, and astigmatism axis angle A are calculated from the detection results. In addition to a two-dimensional CCD, the solid-state image sensor has three one-dimensional CCDs arranged radially or in parallel, and detects the coordinates of the intersection with the corneal reflection image, or the height or diameter from a predetermined point to the intersection. It may be something you do. As an example of identifying the corneal reflection image,
General 2 from the obtained intersection coordinates of at least 5 points
The following curve formula ax ² +b×Y+cY ² +dx+eY+1=0
Solve to calculate coefficients a to e.

The refractive power and corneal shape of the eye to be examined determined in the above manner are displayed on the image display element 24, for example, on the seventh screen.
The image is observed or photographed through a lens 25, a mirror 26, and an observation or photographing optical system as shown in the figure.

The above is an example of a surgical microscope that has both a refractive power measurement function and a corneal shape measurement function, but the following replacements are also possible. That is, the beam splitters 13 and 14 are separated into wavelengths by having predetermined spectral characteristics (the horizontal axis is wavelength λ, the vertical axis is transmittance T), and short wavelengths are used for observing or photographing the anterior segment of the eye. , a longer wavelength may be used during measurement, or the beam splitter 1 may be used.
3 and 14 may be used as escape mirrors and moved out of the optical path except during measurement. Other means for separating the light for observation and photographing and for measurement may be to change the blinking frequency of the light source and to separate the detector by providing a corresponding selection circuit. It is also possible to use a ring-shaped line light source instead of the light sources 32a, 32b, . . . , 32j, or to arrange the light emitting elements themselves.

On the other hand, it is also possible to connect to video recording by using an image pickup tube or the like as a recording means. That is, for example, in FIG. 1, the mirror 10 is replaced with a half mirror, and the light beam passing through this is guided to the image pickup tube and used as a recording means.

By the way, in Figure 1, the central part of the eye to be examined is shown being observed (the axis of the eye to be examined O ₁ and the optical axis of the microscope O ₂ coincide), but now the eye to be examined is being observed as shown in Figure 8. When observing the periphery of the eye, that is, when the eye axis O ₁ to be examined and the optical axis O ₂ of the microscope are deviated in parallel, consider measuring the eye refractive power while keeping the observation system fixed.

At this time, as shown in FIG. 8 as a conceptual diagram, if the projection chart 18 is moved in the direction perpendicular to the optical axis in synchronization with the light receiving chart 22, it is possible to measure the eye refractive power through the central region C of the cornea of the eye to be examined. Become.

Furthermore, since the corneal reflection image of the projection chart 18 is formed on the anterior segment of the subject's eye, it is also possible to observe it with a microscope that focuses on the anterior segment of the subject's eye.

Note that in order to effectively guide the light beam from the projection chart to the eye flesh, it is necessary to move it perpendicular to the optical axis in synchronization with the aperture stop 38.

In the above explanation, instead of moving both the projection chart 18 and the light receiving chart 38 synchronously, the projection chart 1 is moved to an optically conjugate position 100.
An index similar to 8 may be provided and only this index may be moved perpendicular to the optical axis. In this case, projection chart 1
8. The light receiving chart 38 becomes unnecessary.

Note that other indicators may be provided at the conjugate position 100 instead of the three slits, for example, a chart having a circular opening.

Similarly, a similar aperture stop can be provided at a position optically conjugate with the aperture stops 28 and 38, and the eye refractive power can be measured by moving this aperture perpendicular to the optical axis.

Next, let us consider measuring the corneal shape while keeping the observation system fixed.

In this case, the light sources 32a, 32b, . . . are moved integrally perpendicular to the optical axis, and the corneal reflection images are set to be symmetrical about the eye axis _O1 to be examined. As a result, as in the case of eye refractive power measurement shown in _FIG . Shape measurement becomes possible.

Incidentally, although a real image of the projection chart 18 is formed on the fundus of the subject's eye as an index image, the microscope observation system is focused on the anterior segment of the subject's eye and cannot observe the fundus.

Therefore, as shown in FIG. 9, the photographing lenses 6 and 7 shown in FIG. 1 are removed from the observation and photographing optical path, and a new movable photographing lens 104 is placed in the optical path to focus on the fundus of the subject's eye. By doing so, it becomes possible to move the projection chart 18 perpendicularly to the optical axis and observe the fundus image with a microscope to measure the eye refractive power in the central region of the eye to be examined.

As shown in FIG. 10, a ring slit 101 and a relay lens 102 are provided as an illumination system for fundus observation, and a mirror 103 is provided in place of the lens-equipped prism 4. The ring slit 101 is brought into an almost optically conjugate relationship with the cornea of the eye Ep by the relay lens 102 and the objective lens 5.

Next, what is shown in FIG. 11 is an embodiment using an alignment chart 30, and as shown in FIG. 12, the alignment chart 30 has a ring opening 30a in the center and a It can be moved in and out to the focus position of the microscope.

When the alignment chart 30 is observed with a microscope, an iris image 110' of the eye to be examined is observed together with its image 30a' as shown in FIG.
a′, etc., and the aperture diaphragm 28 when measuring the eye refractive power.
A corneal reflection image 28 and the like are observed.

These and image 3 of alignment chart 30
By making 0' concentric, the central region of the eye to be examined can be recognized.

When measuring the peripheral area of the eye to be examined, the aperture diaphragm 28 and the like are moved perpendicular to the optical axis, and the position of the corneal reflection image is displaced while being observed under a microscope as shown in FIG. Furthermore, by moving the light source 32a and the like perpendicularly to the optical axis, measurements with angle of view characteristics can be performed.

At this time, the x-axis, y-axis
Adding axis scales and angle scales is convenient for obtaining quantitative distributions.

Although observation using a finder has been described above, it goes without saying that this can also be imaged with an imaging tube, CCD, or other imaging means, monitored, or captured on video.

As described above, according to the present invention, an index image is moved perpendicularly to the optical axis using a chart projected onto the fundus or an index projected onto the cornea, or an aperture that is optically approximately conjugate with the anterior segment of the subject's eye. By moving perpendicular to the optical axis, it is possible to measure the eye refractive power and corneal shape in different areas of the eye to be examined while keeping the main body fixed.

Note that the present invention is not limited to what is shown in the above-mentioned embodiments. For example, the projection optical system such as a projection lens may be moved perpendicular to the optical axis while the index is fixed, and the index image may be moved perpendicular to the optical axis. You can let me.

In addition, in the examples, detection was performed using eye refractive power or corneal shape, but it is not limited to this.
This includes all similar detection of eye information to be examined, such as the intensity of scattering of the crystalline lens.

[Brief explanation of drawings]

Fig. 1 is a diagram of an embodiment of the present invention, Fig. 2 is a projection chart of the eye refraction measurement system, and Figs. 3 and 4 are the aperture diaphragms on the light emitting side and light receiving side of the eye refraction measurement system, respectively. Figure 5 is a diagram of the light reception chart of the eye refraction measuring system.
Figure 6 is a layout diagram of the light source of the corneal topography measurement system, Figure 7 is an explanatory diagram of the image display element that displays measurement data of refractive power and corneal shape, and Figure 8 is a mismatch between the eye axis of the subject and the optical axis of the microscope. Figure 9 is a modified example of the observation system, showing an optical system focused on the fundus, Figure 10 is an illustration of the ring slit, and Figure 11 is an illustration of the alignment chart. FIG. 12 is an explanatory diagram of an alignment chart, and FIGS. 13 and 14 are explanatory diagrams of the case where measurement is performed in the central region and peripheral region of the eye to be examined, respectively. In the figure, Ep is the eye to be examined, E is the observation eye, La and Lb are lens systems, 1 is a lamp for observing the anterior segment of the eye, 4 is a prism with a lens, 5 is an objective lens, 9 is a flip-up mirror, and 11 is an eyepiece lens, 12 is image recording means, 1
8 is a projection chart for measuring eye refractive power, 18a, 1
8b, 18c are slits, 20 is a light source for measuring eye refractive power, 22 is a light receiving chart, 23a, 23b,
23c is a light receiving element, 24 is an image display element, 2
8 and 38 are aperture stops, 30 is an alignment chart, 32a, 32b, . . . , 32j are light sources for corneal shape measurement, and 36 is a solid-state image sensor.

Claims (1)

[Scope of Claims] 1. An observation system for observing the anterior segment of the eye to be examined, and an index that is movable along with the observation system in a direction perpendicular to the optical axis with respect to the eye to be examined, and that projects an index onto the fundus of the eye to be examined or the cornea of the eye to be examined. It has a measurement system that measures predetermined information of the eye to be examined, including a projection system and a light receiving system that receives an index light beam reflected from the fundus or the cornea, and according to the movement of the measurement system and the observation system in the direction perpendicular to the optical axis. The indicator or an optical system for projecting the indicator, or an aperture that is optically substantially conjugate with the anterior segment of the eye to be examined in the measurement system, so as to move the pass range of the indicator light flux in the anterior eye segment of the eye to be examined, is another part of the measurement system. An ophthalmological device characterized in that it is displaceable in a direction perpendicular to an optical axis with respect to a member.