JP2802356B2 - Fundus camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus camera, and more particularly to a fundus camera capable of performing infrared fluorescence photography.

[0002]

2. Description of the Related Art One of health examinations is a fundus examination for examining the condition of blood vessels in the fundus, and a fundus camera is used to photograph the condition of the fundus. In recent years, a fundus camera capable of infra-red fluorescence imaging has been proposed in which a fluorescent material is injected into blood of a subject and a fluorescent blood vessel image is captured by infrared light.

[0003] A conventional fundus camera capable of infrared fluorescence photography will be described.

[0004] Indocyanine green (hereinafter referred to as I) is a fluorescent agent having an absorption peak at 780 nm in the infrared.
CG). As a light source for projecting measurement light to the fundus of the subject, a xenon lamp is generally used, and only infrared light is projected. That is, an exciter filter that transmits light in a wavelength range absorbed by the ICG and cuts light on a longer wavelength side is provided on the light projecting side, and infrared light is projected through the exciter filter. ICG in blood
Absorbs infrared light having a peak at 780 nm as shown by the curve 27a in FIG.
It emits fluorescence having a center wavelength of 20 nm. A barrier filter is provided on the light receiving side, transmits light in the wavelength range of the fluorescent light, cuts light on the shorter wavelength side, receives only the fluorescent light, and clearly captures an image of a fundus blood vessel.

However, after the ICG is injected, a predetermined time (3
When the albumin in the blood and ICG have bound after elapse of about 0 seconds, the peak of the absorption wavelength changes from 780 nm to 805 nm as shown by the curve 27b in FIG. 2, and the peak of the fluorescence wavelength also changes with the curve in FIG. As shown at 28b, 835
nm.

Therefore, it is not possible to take a sufficiently clear image after a predetermined time has elapsed.

In consideration of such a change in the fluorescence wavelength, a fundus camera that captures a fundus image by providing the above-described exciter filter and barrier filter in accordance with the wavelength range after a predetermined time has elapsed has been proposed.

[0008]

One of the advantages of infrared fluorescence imaging is that the behavior of blood infused with a fluorescent agent in blood vessels can be observed. In order to record the state of change from the injection of the fluorescent agent, continuous shooting as a moving image is performed over time, or a large number of continuous shootings are performed over time.

[0009] However, in the above-mentioned conventional example, in the former case, appropriate photographing is performed in the initial state in which the binding between albumin and ICG in blood has not begun.
If the peaks of the absorption wavelength and the fluorescence wavelength shift to the longer wavelength side after the coupling of G, the illumination light beam is cut by the exciter filter, and the photographing light that is the fluorescence is cut by the barrier filter, and the photographing after a predetermined time elapses is effective. Can not be done.

[0010] In the prior art, the latter can take a picture after a predetermined time satisfactorily, but there is a problem that an effective picture cannot be taken in an initial state.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fundus camera capable of effectively photographing even after a lapse of a predetermined time from an initial state in which a fluorescent agent is injected.

[0012]

The present invention illuminates the fundus of the eye to be examined.
A fundus illumination system to illuminate and a fundus image
In a fundus camera provided with a photographing system, the first wavelength range
A first exciter filter transmitting infrared light;
The second wavelength range shifted to the longer wavelength side with respect to the first wavelength range
A second exciter filter transmitting infrared light of
The third wavelength is disposed interchangeably in the fundus illumination system.
Barrier filter that transmits infrared fluorescence in the
The fourth wavelength region shifted to the longer wavelength side with respect to the third wavelength region
Can be replaced with a second barrier filter that transmits infrared fluorescence
The present invention relates to a fundus camera arranged in the photographing system, and a fluorescent agent.
After the elapse of a predetermined time after the injection of
And the second exciter filter is replaced with the second exciter filter.
The first barrier filter and the second barrier filter are inserted.
The present invention relates to a fundus camera having a driving means for changing
For the infrared laser light in the constant wavelength range and the first specific wavelength range.
Laser of second specific wavelength band shifted to longer wavelength side
A laser light source for emitting light, and the first specific wavelength range
Infrared laser light and infrared laser of the second specific wavelength range
A fundus illumination system for selectively projecting light to the fundus of the eye to be examined
And the infrared light of the specific wavelength range
Blood in the fundus of the eye to be examined through a barrier filter
The present invention relates to a fundus camera having a photographing system for photographing a tube image.
Light emission for further changing the light emission condition of the laser light source.
The present invention relates to a fundus camera provided with condition changing means, and
The light emission conditions are changed by controlling the temperature of the laser light source.
The present invention relates to a fundus camera to be converted.

[0013]

[Function] When a fluorescent material is injected into blood and a blood vessel of the fundus is photographed by fluorescence, even if the absorption characteristic and the luminescence characteristic of the fluorescent material change due to the combination of the fluorescent material and the blood, the photographing is properly performed. , Perform dynamic shooting over time.

[0014]

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a fundus illumination system 1 includes a xenon light source 2 as a light source for photographing, a condenser lens 3, exciter filters 4a and 4b, a ring aperture 5 having a ring hole, a reflecting mirror 6, a relay lens. 7. Consisting of a perforated mirror 8 having a transmission hole formed in the center, the illumination light beam from the xenon light source 2 is limited to infrared light, and a ring-shaped light beam is formed on the fundus of the eye 9 to be examined by the ring stop 5. Emits light. The ring stop 5 and the pupil of the subject's eye 9 are arranged at conjugate positions.

The exciter filter 4 a and the exciter filter 4 b are provided so as to be interchangeable with respect to the optical axis 10 of the fundus illumination system 1.
Transmits infrared light having a peak near 780 nm, which is absorbed by ICG, and cuts light having a longer wavelength. The light transmission characteristic of the exciter filter 4a is shown by a curve 24a in FIG. In the exciter filter 4a having the light-transmitting characteristics, infrared light having a wavelength near the peak at 780 nm absorbed by ICG is effectively transmitted, but infrared light having a wavelength near 820 nm is not transmitted.

The light transmission characteristic of the exciter filter 4b is shown by a curve 24b in FIG. As shown by the curve 24b in FIG. 3, the exciter filter 4b having the light-transmitting property transmits infrared light near 805 nm, which is the peak of the wavelength absorbed in a state where albumin and ICG are combined, and has a wavelength of 835 nm.
Infrared light of a nearby wavelength is not transmitted.

The exciter filter 4a and the exciter filter 4b are configured to move in conjunction with each other, and drive means such as a solenoid (not shown) are connected. Further, a timer is provided in a drive circuit of the drive means. The exciter filter 4a and the exciter filter 4b are exchanged.

The photographing system 11 includes an objective lens 12, a photographing aperture 13, barrier filters 14a and 14b, and a focusing lens 1.
5, imaging lens 16, reflecting mirror 17, field lens 1
8, a reflecting mirror 19, a relay lens 20, and an image pickup tube 21. The output from the image pickup tube 21 is displayed on a monitor television 23. The photographic stop 13 and the pupil of the subject's eye 9 are arranged at conjugate positions.

The photographing aperture 13 blocks the ring-shaped reflected light reflected by the cornea and transmits only the photographing light flux from the fundus.

The barrier filter 14a and the barrier filter 14b are provided so as to be interchangeable with respect to the optical axis 25 of the photographing system 11, and the barrier filter 14a has a transmission curve like a curve 26a in FIG. Fluorescence peak wavelength 8
It transmits infrared light near 20 nm and cuts infrared light on the shorter wavelength side. Therefore, the luminous flux from the fundus is cut off, and only the fluorescence is transmitted.

The barrier filter 14b corresponds to the curve 2 in FIG.
6b, and has a fluorescence peak wavelength of 835 n
The infrared light near m is transmitted, and the infrared light on the shorter wavelength side is cut off. Therefore, only the fluorescence emitted in a state where albumin and ICG are bound is transmitted, and other reflected light from the fundus is cut off.

The barrier filter 14a and the barrier filter 14b are moved in conjunction with each other. A drive means such as a solenoid (not shown) is connected, and a drive circuit of the drive means is provided with a timer. The barrier filter 14a and the barrier filter 14b are exchanged.

If the exciter filter 4a and the barrier filter 14a are arranged on the optical axis at the beginning of the inspection, and the exciter filter 4b and the barrier filter 14b are replaced after a predetermined time has elapsed, the inspection can be performed. From the beginning to the end of the examination, it is possible to photograph only with the fluorescence, and a clear image can be obtained.

Next, although a xenon light source is used as the light source in the above embodiment, a laser light source which is a single wavelength light source is used.
Two types of wavelengths may be emitted from the laser light source.
For example, as shown in FIG. 4, a laser light source 29a that emits infrared light of 780 nm and a laser light source 29b that emits infrared light of 805 nm are provided. The laser light source 29a is turned on in the early stage of the examination, the infrared light from the laser light source 29a is irradiated, and after a lapse of a predetermined time, the laser light source 29a is turned off. The laser light source 29b is turned on to emit infrared light from the laser light source 29b.

In FIG. 5, a curve 31a represents the laser light source 29.
a indicates the infrared light emitted, and a curve 31b indicates the infrared light emitted from the laser light source 29b. As in this example,
When using a short wavelength light source, the barrier filter is 820
nm and 835 nm, and one type of barrier filter that cuts infrared light on the shorter wavelength side than near 805 nm may be provided.

The emission wavelength of the laser light source changes by changing the emission condition of the laser light source. Therefore, two types of wavelengths may be emitted by using the same laser light source and controlling, for example, temperature, which is one of the emission conditions. Further, it goes without saying that a CCD camera or the like can be used as the image pickup means instead of the image pickup tube.

[0028]

As described above, according to the present invention, when performing a fundus examination using a fluorescent agent, even if the absorption characteristics of the fluorescent agent change with time, the fundus is always photographed under appropriate conditions. It is possible to perform a dynamic fundus examination over time with high accuracy.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing absorption characteristics of a fluorescent agent.

FIG. 3 is a diagram illustrating light transmission characteristics of a filter.

FIG. 4 is an explanatory view showing a light source unit of another embodiment.

FIG. 5 is a diagram showing a light emitting characteristic of a laser light source and a light transmitting characteristic of a filter in the other embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fundus illumination system 2 Xenon light source 4a Exciter filter 4b Exciter filter 9 Examinee eye 11 Imaging system 14a Barrier filter 14b Barrier filter 29a Laser light source 29b Laser light source

Claims (5)

(57) [Claims] 1. A fundus camera having a fundus illumination system for illuminating a fundus of a subject's eye and a photographing system for photographing a fundus image of the subject's eye, transmitting infrared light in a first wavelength range. First
And a second exciter filter that transmits infrared light in a second wavelength range shifted to a longer wavelength side with respect to the first wavelength range and is exchangeably disposed in the fundus illumination system. In addition, a first barrier filter that transmits infrared fluorescence in a third wavelength range and a second barrier filter that transmits infrared fluorescence in a fourth wavelength range shifted to a longer wavelength side with respect to the third wavelength range. A fundus camera, wherein a barrier filter and a filter are interchangeably arranged in the photographing system. 2. A driving means for exchanging the first exciter filter and the second exciter filter after a predetermined time has elapsed after injection of the fluorescent agent, and exchanging the first barrier filter and the second barrier filter. Claim 1 provided with
Fundus camera. 3. An infrared laser beam of a first specific wavelength band and an infrared laser beam of a second specific wavelength band shifted to a longer wavelength side with respect to the first specific wavelength band. A laser light source, the infrared laser light of the first specific wavelength range, and the second
A fundus illumination system for selectively projecting the infrared laser light of the specific wavelength region to the fundus of the eye to be examined, and a barrier filter which transmits infrared fluorescent light of the specific wavelength region from the fundus of the eye to be inspected. An imaging system for imaging a fluorescent blood vessel image of the fundus of the eye to be examined. 4. The fundus camera according to claim 3, further comprising light emission condition changing means for changing the light emission condition of the laser light source. 5. The fundus camera according to claim 4, wherein the light emission condition is changed by controlling a temperature of the laser light source.