JPH02149246A - fundus 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 (Industrial Application Field) The present invention relates to a fundus camera capable of observing and photographing using visible light and infrared light.

(Prior art) When performing infrared fluorescence photography with a fundus camera, for example, an IC having an absorption characteristic peak at a wavelength of 800 μ mark is used as a fluorescent agent.
Inject G (indocyanine green) into the subject's vein (
(hereinafter simply referred to as intravenous injection).

On the other hand, on the fundus camera side, an exciter filter that can transmit infrared excitation light in a wavelength range including 800 μm is installed in the photographic illumination optical system, and the photographic illumination light source is adjusted so that the fluorescent agent reaches the retinal blood vessels. lights up and starts shooting.

As a result, of the light from the photographic illumination light source, only the infrared excitation light absorbed by the ICG passes through the exciter filter as a fluorescence excitation wavelength and is projected onto the fundus of the subject's eye. This fluorescence excitation wavelength is absorbed by the fluorescent agent that has reached the fundus blood vessel and excites this fluorescent agent. Due to this excitation, fluorescence is emitted from the fluorescent agent, and this fluorescence is guided to the film surface via the photographing optical system. As described above, fundus cameras capable of photographing using infrared fluorescence have been conventionally considered.

(Problems to be Solved by the Invention) However, infrared light has a longer optical path length than visible light, and it has not been possible to observe and photograph both types using the same fundus camera.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a fundus camera that can perform observation and photographing using visible light and infrared light.

(Means for Solving the Problems) For this purpose, in the fundus camera of the present invention, a visible light filter and an infrared light filter including a barrier filter are selectively inserted into the optical path of the observation and photographing optical system. In a removably provided fundus camera, when the visible light filter is formed thicker than the infrared light filter, and the transmitted light wavelength of the filter inserted in the middle of the optical path is used. The thickness of each filter is set so that the fundus of the eye to be examined and the imaging surface are conjugate.

(Function) According to such a configuration, immediately after focusing on the fundus of the subject's eye using a predetermined filter, even if another filter is placed in the optical path of the observation/photography optical system and observation/photography is performed, By changing the thickness of this filter, the optical path length is automatically corrected and the image is brought into focus.

(Example) The present invention will be explained below based on the drawings.

In FIG. 1, an illumination optical system (2) and an observation/photography optical system (II) are provided in the main body (not shown) of the fundus camera.

The illumination optical system I has an observation illumination optical system and a photographic illumination optical system, and the observation photographic optical system I+ has a photographic optical system, an observation optical system, and a monitor optical system.

The observation illumination optical system includes an observation illumination light source 1. Condenser lens 2. Semi-transparent mirror 3. Ring slit plate 4. Relay lens 5. Perforated diagonal mirror 6. It has optical members such as an objective lens 7. Illumination light from the observation illumination light source 1 is projected onto the fundus E'' of the eye E to be examined through optical members from the condenser lens 2 to the objective lens 7.

Further, the photographing illumination optical system includes a photographing illumination light source 8. Condenser lens9. It also includes optical members from the semi-transparent mirror 4 to the objective lens 7 of the observation/photography illumination optical system.

The illumination light of the photographic illumination light source 8 is the photographic illumination light source 8,
Condenser lens9. The image is then projected onto the fundus E' of the eye E to be examined through the optical members from the semi-transparent mirror 4 to the objective lens 7 of the observation/photography illumination optical system.

Furthermore, a visible fluorescence excitation filter 10 and an infrared fluorescence excitation filter 11 are removably installed as exciter filters in the optical path of the illumination optical system, that is, between the ring slit plate 4 and the relay lens 5. . The visible fluorescence excitation filter 10 and the infrared fluorescence excitation filter 11 are selectively inserted into and removed from the optical path by a driving means 12 such as a solenoid or a motor.

In addition, the photographing optical system includes an objective lens 7 and a perforated oblique mirror 69.
Focusing lens 13. Imaging lens 14. -eye reflex camera 15
(detailed illustration path) is provided with a film surface F (imaging surface). The reflected light or fluorescence from the fundus Ef is then reflected by the objective lens 7, the perforated oblique mirror 69, the focusing lens 13. Imaging lens 1
4 to the film plane F.

The observation optical system includes optical members of the photographic optical system from the objective lens 7 to the imaging lens 14, and - a quick return mirror 16 in the reflex camera 15. Focus glass 17, reflector 1
8. and an eyepiece lens 19. By disposing the quick return mirror 16 between the imaging lens 14 and the film surface F, the reflected light or fluorescence from the fundus Et guided by the imaging lens is transferred to the focusing glass by the quick return mirror 16. 17, and a fundus image is formed on this focusing glass 17. This fundus image is observed by the examiner's eye 20 via the reflector 18 and the eyepiece 19.

The monitor optical system includes an objective lens 7, a perforated oblique mirror 6, and a focusing lens 13. Imaging lens 14. A quick return mirror 21 is removably installed between the imaging lens 14 and the single-lens reflex camera 15. Lens 221 Reflector 23° Lens 24. It has a TV camera 25 and a monitor TV 26.

By disposing this quick return mirror 21 in the optical path between the single-lens reflex camera and the single-lens reflex camera 5, the reflected light or fluorescence from the fundus E+ guided by the imaging lens is reflected by the quick return mirror 21. Lens 22 Reflector 23.
It is guided to a TV camera 25 via a lens 24. An image of the fundus is displayed on the monitor TV 26 based on the output from the TV camera 25.

Further, in the optical path between the perforated oblique mirror 9 and the focusing lens 13, an infrared cut filter 27 and a visible fluorescence filter 28, which is a barrier filter, can be inserted and removed as visible light filters. Infrared light filters such as an infrared fluorescence filter 29 and a visible cut filter 29a, which are barrier filters, are provided in a freely insertable and removable manner. These infrared cut filter 27, visible fluorescence filter 28.
and infrared fluorescence filter29. Visible cut filter 2
9a is inserted into and removed from the optical path between the perforated oblique mirror 9 and the focusing lens 13 by a driving means 30 such as a motor or a solenoid.

Note that when observing and photographing the fundus using visible light, filter 10. 11 is removed from between the ring slit plate 4 and the relay lens 5, and an infrared cut filter 27 is inserted between the perforated oblique mirror 6 and the focusing lens 13.

In addition, when photographing the fundus using visible fluorescence, the visible fluorescence excitation filter 10 is inserted between the ring slit plate 4 and the relay lens 5, and the visible fluorescence filter 28 is inserted between the perforated diagonal peg 6 and the focusing lens 13. Put it in between.

Furthermore, when photographing infrared fluorescence, an infrared fluorescence excitation filter 11 is inserted between the ring slit plate 4 and the relay lens 5, and an infrared fluorescence filter 29 is inserted between the perforated oblique mirror 6 and the focusing lens 13. Put it between. However, in this way, each filter 11. 29, until a certain amount of infrared fluorescent agent reaches the fundus blood vessels, even if infrared fluorescence excitation light is projected onto the fundus, the amount of fluorescence from the fundus blood vessels is insufficient. It is not possible to observe or photograph the fundus. Moreover, when photographing the fundus, it is necessary to perform positioning and alignment with the bottle before starting photographing. Therefore, while the amount of fluorescent light is insufficient, the filter 1129 should be removed from each optical path, and the infrared cut filter 2 should be removed.
7 or a visible cut filter 29a is inserted between the oblique perforated mirror 6 and the focusing lens 13, and the fundus of the eye is observed using visible light or infrared light.

Here, if the thickness of the infrared cut filter 27 is A, the thickness of the visible fluorescence filter 28 is B, the thickness of the infrared fluorescence filter 29 is C1, and the thickness of the visible cut filter 29a is D, then these Thickness A.

B, C, D are A=B>C=D The relationship is set as follows.

Moreover, the thickness of the infrared cut filter 27 and the visible fluorescence filter 28 is the same as that of the filter 27. 28 is inserted in the optical path, and the filter 27. The wavelength of the transmitted light is set at a value such that the fundus of the subject's eye and the imaging surface become conjugate with the wavelength of the transmitted light, that is, the visible light (including visible fluorescence) from the fundus. In addition, the thickness of the infrared fluorescence filter 29 and the visible cut filter 29a is such that when the filter 29 is inserted in the middle of the optical path, the wavelength of the transmitted light of the filter 29, that is, the infrared fluorescence from the fundus, can be adjusted between the fundus of the examined eye and the imaging surface. is set to a value such that and are conjugate.

Therefore, when taking infrared fluorescence photography, infrared cut filter 2
Immediately after focusing using visible light or infrared light using the visible cut filter 29a, the focus will not shift even if infrared fluorescence photography is performed using the infrared excitation light using the infrared fluorescence filter 29. do not have.

(Effects of the Invention) As explained above, the present invention provides a fundus camera in which a visible light filter and an infrared light filter including a barrier filter are selectively installed in the optical path of an observation and photographing optical system. In this case, the visible light filter is formed to be thicker than the infrared light filter, and when the transmitted light wavelength of the filter inserted in the middle of the optical path is used, the fundus of the examinee's eye and the imaging surface are different from each other. Since the thickness of each of the filters is set to be conjugate, it is possible to perform observation and photographing using visible light and infrared light using the same fundus camera.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an optical system of a fundus camera according to the present invention. ■...Illumination optical system +1...Observation and photographing optical system F...Film surface (imaging surface) E+...Fundus 10...Visible fluorescence excitation filter (exciter filter) 11...Infrared Fluorescence excitation filter (exciter filter) 10-

Claims (1)

[Claims] (1) In a fundus camera in which a visible light filter and an infrared light filter including a barrier filter are selectively installed in the optical path of an observation and photographing optical system in a removable manner, the visible light filter is attached to the infrared light filter. Each of the filters is formed thicker than the optical filter, and has a thickness such that the fundus of the subject's eye and the imaging surface are conjugated when using the wavelength of transmitted light of the filter inserted in the middle of the optical path. A fundus camera characterized by having a thickness of .