JPS631852B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fundus observation and photographing device that detects the opacity of the crystalline lens of an eye to be examined.

In general, when observing and photographing the fundus with a fundus camera, it is well known that reflected and scattered light from illumination light from the cornea and crystalline lens of the eye to be examined mixes into the photographing light flux and deteriorates the image quality. On the other hand, it is well known that even if the light beams are completely separated in regions such as the cornea and crystalline lens, as the opacity of the crystalline lens increases, the amount of scattering increases, resulting in a decline in image quality.

An object of the present invention is to provide a fundus observation and photographing device that detects the degree of opacity of a transparent body such as a crystalline lens in an eye to be examined, and improves the diagnostic function of a transparent body opaque eye. It is characterized by having means for projecting an index image onto the fundus in an optical system that illuminates the fundus, and means for measuring the amount of light corresponding to the opacity of the eye to be examined in a portion corresponding to the index image. .

The present invention will be explained in detail below based on illustrated embodiments.

FIG. 1 is a configuration diagram showing an example of the optical system of a fundus camera. Reference numeral 1 is an observation light source consisting of a tungsten lamp, etc., and the light emitted from this observation light source 1 is transmitted through a condenser lens 2, a xenon discharge tube, etc. The light enters a mirror 5 through a photographing light source 3 and a condenser lens 4, and is deflected there and then sequentially passes through a ring slit plate 6, a relay lens 7, an index 8 that can be inserted and removed from the optical path, and a relay lens 9. and reaches the perforated mirror 10.
The light that enters the perforated mirror 10 from this illumination optical system is reflected by the perforated mirror 10 in the direction of the eye E to be examined, irradiates the fundus Ef of the eye E to be examined, is reflected here, passes through the original optical path, and further Hole mirror 10
and reaches the observation optical system. An objective lens 11 is provided between the perforated mirror 10 and the eye E to be examined.
are arranged, and behind the perforated mirror 10, a photographing lens 12 and a flip-up mirror 1 are arranged along the optical axis.
3. Photographic films 14 are arranged in sequence.
On the reflection side of the flip-up mirror 13, a half mirror 15, a field lens 16 placed in a position conjugate with the photographic film 14, a mirror 17 for changing the optical path, and a viewfinder 18 are arranged in sequence along the optical axis. . Further, on the reflection side of the half mirror 15, a one-dimensional solid-state image sensor 19 is mounted on the photographic film 14.
A display device 20 such as a light emitting diode is provided near the field lens 16 and directed toward the viewfinder 18 . Note that e is the examiner's eye, and a short wavelength cut filter 21 can be freely inserted and removed between the mirror 5 and the ring slit plate 6.
is located.

In this fundus camera, the observation light source 1 and the photographing light source 3 are substantially conjugate with respect to the condenser lens 2, and the observation light source 1 is turned on during observation, and the photographing light source 3 is turned on instantaneously during photography. The light source image is once formed near the ring slit plate 6 by the condenser lens 4, and then an image of the annular opening of the ring slit plate 6 is formed near the perforated mirror 10 by the relay lenses 7 and 9, where the illumination is performed. The light is reflected and travels to the left. And objective lens 1
1, an image of the annular aperture is formed near the crystalline lens of the eye E to be examined, and then the fundus Ef is illuminated.

The reflected light from the fundus Ef travels to the right and is once formed into an image by the crystalline lens and objective lens 11, then passes through a perforated mirror 10 and a photographic diaphragm (not shown), and is focused into an image by the photographic lens 12. Become.
During observation, the fundus image is guided upward by the flip-up mirror 13 located at the solid line position and observed by the examiner's eye e through the viewfinder 18, and when photographing, the flip-up mirror 13 is moved to the dotted line position as shown by the arrow. The fundus image is formed on the photographic film 14 via an open shutter (not shown).

The index 8 inserted into the illumination optical system to form a target image on the fundus Ef is movable in the optical axis direction, and performs linear imaging in a direction perpendicular to the longitudinal direction of the one-dimensional solid-state image sensor 19. It has an image pattern. For example, when the photographic lens 12 is moved for focusing, the index 8 is linked with the photographic lens to maintain a conjugate relationship with the fundus Ef and the photographic film 14.

FIG. 2 shows an image observed through the viewfinder 18 when the index 8 is focused well on the fundus Ef, and an index image 8a of the index 8 is observed on the fundus Ef.

The index image 8a of the index 8 formed on the fundus Ef is
One-dimensional solid-state image sensor 19 via half mirror 15
Projected orthogonally above. FIG. 3 shows this situation. Since the output on the image sensor 19 when a well-focused image is formed on the fundus Ef differs depending on the opacity of the transparent body of the eye to be examined, the opacity depends on the magnitude of the output. can be detected.

4 and 5 are examples showing the output of the image sensor 19 for a standard eye and a cloudy eye, respectively. At the position of the index image 8a on the image sensor 19, the outputs are I ₁ and I _2, respectively. . That is, since the output in FIG. 5 is due to a cloudy eye, I ₂ >I ₁ due to an increase in flare components due to scattered light.

This result can be shown, for example, on the display means of a display 20 disposed near the field lens 16 in FIG. FIG. 6 shows an example in which the indicator 20 is turned on when the degree of turbidity exceeds a certain level of intensity, and the viewfinder 18 displays a warning light 20a. Here, if the display 20 is to display numbers, the numerical value of the turbidity can be observed as shown in FIG.

Next, we will discuss the procedure for fundus photography.
After focusing on Ef, the index 8 and flip-up mirror 13 are retracted and the photographing light source 3 is made to emit light. As a result, the image of the fundus Ef is
Recorded in 4. At this time, data on the eye opacity at the time of the previous observation can be recorded on the photographic film 14 at the same time. FIG. 9 shows an example of this recording apparatus, in which data is displayed on a display 22 such as a light emitting diode, and is recorded on a photographic film 14 via a lens 23 and a mirror 24. FIG. 10 shows an example of the recording. For example, the turbidity is expressed numerically as 5.6.

Further, when the turbidity exceeds the reference value during photographing, it is preferable to insert a short wavelength cut filter 21 which is removably provided in the optical path as shown in FIG. For example, as shown in FIG.
It has the property of blocking the following light. This short wavelength cut generally has a wavelength λ≦λ ₀ (however, 500nm>
A filter that cuts out light in the short wavelength region (λ ₀ >350 nm) is practically sufficient. By using this short wavelength cut filter 21, scattering in the eye to be examined can be reduced and the freshness of the image can be improved.

Although the above-described embodiment shows the case where the degree of turbidity is measured using observation light, if the index 8 is always placed, it is also possible to obtain and calculate the degree of turbidity using strobe light during photographing. It goes without saying that fundus photography can also be performed by inserting the short wavelength cut filter 21 according to the above procedure.

As explained above, the fundus observation and photographing device according to the present invention can accurately determine the degree of cataract etc. by detecting the opacity of the transparent material of the eye to be examined, and can also determine the degree of cataract etc. as necessary. By inserting a short-wavelength cut filter that reduces scattered light, it is possible to obtain fundus observation images with excellent image quality, which can greatly contribute to the diagnosis of opaque eyes.

[Brief explanation of the drawing]

The drawings show an embodiment of the fundus observation and photographing device according to the present invention, FIG. 1 is a configuration diagram thereof, FIG. 2 is an explanatory diagram showing an index projected onto the fundus, and FIG. 3 is an illustration showing an index image projected onto an image sensor. An explanatory diagram of the state, Figures 4 and 5 are graphs of the output of the index image on the image sensor, Figure 6 is an explanatory diagram that displays a turbidity warning by lighting, and Figure 7 is an illustration of the turbidity based on the measured value. Figure 8 is a characteristic diagram of a filter to reduce scattering according to turbidity, Figure 9 is a block diagram of a device that records turbidity on film, and Figure 10 displays turbidity. It is an explanatory diagram of a photograph of the fundus. 1 is an observation light source, 3 is a photography light source, 6 is a ring slit plate, 8 is an index, 8a is an index image, 10 is a perforated mirror, 11 is an objective lens, 12 is a photography lens,
13 is a flip-up mirror, 14 is a photographic film, 1
5 is a half mirror, 19 is a one-dimensional solid-state image sensor,
20 and 22 are indicators, and 21 is a short wavelength cut filter.

Claims (1)

[Scope of Claims] 1. Means for projecting an index image onto the fundus of the eye into an optical system that illuminates the fundus of the eye to be examined, and means for measuring the amount of light corresponding to the opacity of the eye to be examined in a portion corresponding to the index image. A fundus observation and photographing device comprising: 2. The fundus observation and photographing apparatus according to claim 1, wherein the display means displays a display according to the degree of opacity of the eye to be examined depending on the amount of light. 3. The fundus observation and photographing apparatus according to claim 1, wherein means for projecting the index image onto the fundus is provided in a manner that can be freely inserted into and removed from the illumination optical path. 4. The fundus observation and photographing apparatus according to claim 2, wherein the display by the display means is recorded on a photographic film when photographing the fundus. 5. The fundus observation and photographing device according to claim 1, wherein a short wavelength cut filter that cuts short wavelength region light is provided in the optical path so as to be freely inserted and removed.