JPS60139236A - Eyeground camera - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fundus camera that is improved in terms of operation and ease of use when performing fluorescent fundus photography.

Fluorescence fundus photography is known as a type of ophthalmology photography.
By timing the time when the fluorescent agent injected through the cubital vein reaches the intraocular circulation system, the fundus of the eye is illuminated with blue excitation light, and the green-yellow fluorescence emitted by the fluorescent agent in the blood vessels is photographed. It will be done. At that time, insert an exciter filter having wavelength light transmittance characteristics as shown in AK in Figure 1 into the illumination optical path, and insert a barrier filter with characteristics as shown in Figure 2 in the photographing optical path. is necessary. but,
When both the exciter filter and barrier filter are inserted, the fundus image seen through the finder is
Until the fluorescence begins to appear, nothing can be seen, and even after the fluorescence has appeared, the illuminance of the fluorescence image is low, making it difficult to align and focus the ophthalmological camera with the fundus of the eye being examined. Therefore, first, while looking at the blue fundus with the exciter filter inserted into the illumination optical path, align it with the fundus, adjust the focus, and empirically determine when fluorescence will start to come out from the fundus. Insert the barrier filter and start shooting, or if the insertion of the barrier filter is automated, set the time until the barrier filter is inserted using a timer, etc., and after the set time has elapsed, the barrier filter is inserted and shooting starts. This method was used. This is because in fluorescence fundus photography, it is important to be able to capture the process in which the fluorescent agent begins to emerge from the fundus and spreads. However, the time from when the fluorescent agent is injected until it begins to come out of the fundus of the eye varies from person to person, and varies widely from about 6 to 13 seconds. In order to compensate for this variation, in the above method, to be safe, the barrier filter was inserted and photography started approximately 4 to 5 seconds later, so photography was started several seconds before the fluorescent agent started coming out from the fundus. For the reasons mentioned above, images of the fundus in the dark are often taken, and not only is the film wasted, but the position and focus between the fundus and the camera may be incorrect until the fluorescent agent begins to come out from the fundus. It had the disadvantage of shifting.

SUMMARY OF THE INVENTION An object of the present invention is to provide a camera that eliminates the above-mentioned drawbacks and enables reliably and easily photographing the fundus of the eye without being conscious of operating a barrier filter.

The present invention will be explained in detail based on the embodiments shown in FIG. 2 and below.

FIG. 2 is a configuration diagram showing an embodiment of the optical system of an ophthalmological camera, and 1 is an observation light source consisting of a tungsten lamp or the like, and the light emitted from this tungsten lamp 1 is
A photographing light source 3 consisting of a condenser lens 2a, a xenon discharge tube, etc. enters a mirror 4 through a condenser lens 2b, and is deflected there and sequentially passes through an exciter filter 5,
Ring slit provisional 6, relay lens 7a.

It reaches the perforated mirror 8 via 7b. Incidentally, reference numeral 9 denotes a reflecting mirror arranged behind the observation light source 1 to collect and reflect the light from this lamp. The light that enters the perforated mirror 8 from the above-mentioned illumination optical system is reflected by the perforated mirror 8 in the direction of the eye E to be examined, illuminates the fundus Ef of the examined eye E, passes through the original optical path, and then returns to the perforated mirror 8. and reaches the observation optical system. Hole mirror 8
An objective lens 10 is arranged between the eye E and the eye E, and behind the perforated mirror 8, along the optical axis, a barrier filter 11, a focusing lens 12, a photographing lens group 13, a movable mirror 14, A shutter 15 and a photographic film 16 are arranged in an 8th order. On the reflection side of the movable mirror 140, a field lens 17 placed at a position conjugate with the photographic film 16, a mirror 18 for changing the optical path, and a finder 19 are arranged in sequence along the optical axis. Note that e is the examiner's eye.

Here, the exciter filter 5 is inserted into the illumination optical path by a solenoid 20 during fluorescence photography, and removed from the optical path during other photography, and its operation is confirmed by a microphone switch (not shown). be done. Further, the barrier filter 11 is inserted into and removed from the photographing optical path by driving a solenoid 21.

In the figure, 22 is a beam splitter 123 is an imaging lens, 24 is a filter having the same characteristics as the barrier filter 11, and 25 is a light receiving element for detecting fluorescence.
5 is arranged in a conjugate relationship with the photographic film 16.

Note that the light receiving range of the light receiving element 25 includes the fundus photographing range. That is, in this embodiment, full-plane photometry is performed.

In this ophthalmological camera, the illumination light source 1 and the photographing light source 3 are substantially conjugate with respect to the condenser lens 2a, 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 another condenser lens 2b, and then by the relay lens 7.
Due to a*7b, an image of the annular opening of the ring slit plate 6 is formed in the vicinity of the perforated mirror 8, where the illumination light is reflected and travels to the left.

Then, after forming an image of the annular aperture near the crystalline lens El of the eye E to be examined using the objective lens 10, the fundus gf is illuminated.

The reflected light from the fundus Ef travels to the right, and after being once formed into an image by the crystalline lens E1 and the objective lens 10, it passes through the perforated mirror 8 and the photographing aperture (not shown), and is focused by the focusing lens 12 and photographing lens group 13. It will be imaged. During observation, the fundus image is guided upward by the movable mirror 14 located at the solid line position and observed by the examiner's eye e through the finder 19. At the same time, the fundus image is guided upward by the examiner's eye e through the finder 19. At the same time, the fundus image is guided upward by the examiner's eye e through the finder 19. A focused image is also formed above.

When photographing, the movable mirror 14 rotates to the dotted position, and the fundus image is formed on the photographic film 16 via the opened shutter 15.

FIG. 3 shows a control block circuit according to an embodiment of the present invention, and 31 is an amplification/detection output control circuit for the light receiving element 25;
32 is a power supply/trigger circuit that causes the photographing light source 3 to emit light. Sl is a microswitch that detects that the exciter filter 5 enters the illumination optical path, S2 is a microswitch that detects that the barrier filter 11 enters the photographic optical path, and S3 is a photographic switch. 3
3 is an AND circuit.

When performing fluorescent fundus photography, first a fluorescent agent is injected into the subject,
An exciter filter 5 is inserted, and the fundus Ef is illuminated with light shown in characteristic A in FIG.

At this time, the microswitch s1 for detecting insertion into the optical path of the exciter filter 5 becomes conductive, and the amplification/detection output control circuit 31 starts operating in response to the signal, and starts detecting the emission of fluorescent light from the fundus. The examiner presses the photographing switch s3 to make it conductive, and waits while aligning and focusing the fundus of the examinee's eye with the camera.

After a few seconds, when the fluorescent agent begins to come out from the fundus, the fluorescent light is detected by the light receiving element 25, and its output signal is amplified by the amplification/detection control circuit 31, drives the solenoid 21, and passes through the barrier filter. 11 into the photographing optical path, a signal is also sent to the AND circuit w;I33. When the barrier filter enters the photographing optical path, the confirmation microswitch S2 becomes conductive, and the AND circuit 33 applies an exit signal to the power supply/trigger circuit 32 of the photographing light source, causing the photographing light source 3 to emit light. This allows you to photograph the appearance of the fluorescent agent starting to appear in the fundus. Here, to explain the role of the filter 24 installed in front of the light receiving element 25, the exciter filter 5
Fluorescence from the fundus illuminated with blue light is very weak compared to the background light, that is, blue light, so if fluorescence is detected with blue light directly shining on the photodetector, it will be difficult to detect it due to the difference in intensity. Detection accuracy deteriorates. Therefore, by inserting a filter 24 having the characteristics shown in FIG. 1B in front of the light receiving element,
It becomes possible to cut out background light and detect fluorescent light with high accuracy.

4 and 5 show another embodiment of the invention. The same reference numerals indicate the same members as in FIG. 26 is a beam splitter 127 is a mirror, and 29 is a transparent glass plate as shown in FIG. They are connected by a movable interlocking mechanism 28.

Note that the light receiving element 25 and the glass plate 29 are placed at a position conjugate with the photographic film surface. Regarding this example, below:
explain. It is known that intravenously injected fluorescent agents generally begin to exit from the papilla of the fundus of the eye. Therefore, by matching the light receiving range of the light receiving element 25 with the papilla of the fundus, it is possible to detect the onset of fluorescence with even greater accuracy.

According to this method, the examiner looks at the subject's fundus Ef through the finder 19 and moves the glass plate 29 so that the mark C coincides with the papilla, and the light receiving element 25 is easily aligned with the papilla. can be matched.

In addition, in the control block diagram of FIG. 3, if the camera is on standby without pressing the photographing switch S3 and fluorescence is emitted from the fundus, only the barrier filter 11 can be driven by the signal output from the light receiving element 25. In this case, the examiner can take a photograph at any time while observing the fluorescent image.

In addition, by inserting the barrier filter 11 into the photographing optical path in advance and pressing the photographing switch S3, the examiner can automatically start emitting fluorescent light without having to concentrate on the window 17. It is also possible to take pictures.

Note that it is preferable to limit the operation of the fluorescence detection system to the case where the exciter filter is in the illumination optical path.

- That is, the fluorescence detection system may be operated by the drive signal of the solenoid 20.

As explained above, the fundus camera of the present invention is equipped with a fluorescent light detection element, so that the timing of inserting the barrier filter is automated, and the fundus camera is able to automatically insert the barrier filter at the optimal timing regardless of the examiner's experience or individual differences among the examinees. It became possible to photograph the process of fluorescence starting to appear. Furthermore, since the insertion of the barrier filter is automated, the examiner can focus on positioning and focusing with the subject's fundus until the barrier filter is inserted, allowing for better fluorescence fundus photography. It becomes like this.

[Brief explanation of drawings]

Fig. 1 is a characteristic diagram of an exciter filter and a barrier filter, Fig. 2 is a configuration diagram of a fundus camera according to the present invention, Fig. 3 is a pull diagram of an operating circuit, and Figs. In the figure, 1 is an observation light source, 3 is a photographing light source, 5 is an exciter filter, 8 is a perforated mirror, 10 is an objective lens, 11 is a barrier filter, 1
4 is a movable mirror, 16 is a photographic film, 19 is a finder, 20.21 is a solenoid, 24 is a filter, 2
5 is a light receiving element, and 81.82°S3 is a switch. Applicant Canon Co., Ltd.

Claims (1)

[Scope of Claims] L. A fundus camera capable of photographing the fundus using fluorescence, characterized by having a fluorescence detection means for receiving fluorescence from the fundus at a position substantially conjugate with the fundus. 2. The fundus camera according to claim 1, further comprising a barrier filter driving means for inserting a barrier filter into the photographing optical path, and operating the barrier filter driving means in response to a detection signal from the fluorescence detection means. 2. The fundus camera according to claim 1, further comprising means for causing a photographing light source to emit light during λ photography, and for operating said light emitting means in response to a detection signal from said fluorescence detecting means. 3. The fundus camera according to claim 2, further comprising means for causing a photographing light source to emit light during photographing, and for operating the light emitting means and the barrier filter driving means in response to a detection signal from the fluorescence detecting means. . 5. The fundus camera according to claim 1, wherein the light receiving range of the fluorescence detecting means includes a fundus photographing range. 6. The fundus camera according to claim 1, wherein the light receiving range of the fluorescence detection means has a range corresponding to the papilla, and the fluorescence detection means is movable in a plane perpendicular to the optical axis. 7. The fundus camera according to claim 1, comprising an exciter filter driving means for inserting an exciter filter into the illumination optical path, and operating the fluorescence detecting means in response to a drive signal from the exciter filter driving means. .