JP2002219107A - Fundus imaging device - Google Patents

Abstract

(57) [Problem] To provide a fundus photographing apparatus capable of photographing a good-quality fundus image even in a non-mydriatic mode in which a pupil diameter becomes small. At the time of observation, an illumination optical system (10, 20) causes infrared light to enter through a sclera (white-eye portion) Ec of an eye to be inspected, and the fundus Er is uniformly illuminated with the infrared light, and an image thereof is formed. Are observed on the monitor 38. When shooting, strobes 14, 24
Is emitted, the fundus image passes through the pupil Ep, is imaged by the CCD 35, and is recorded by the recording device 39. In such a configuration, in order to illuminate the fundus, the illumination light passes through the sclera portion of the eye to be examined, while the reflected light from the fundus passes through the pupil Ep to photograph a fundus image. Even in the case of a small pupil diameter, reflected light passing through most of the effective diameter range of the pupil can be used for imaging, and a bright fundus image over a wide area can be captured with good quality.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus photographing apparatus, and more particularly, to illuminate the fundus of a subject's eye with infrared light during observation and illuminate the fundus with visible light during photographing to photograph the fundus. The present invention relates to a fundus photographing apparatus.

[0002]

2. Description of the Related Art Mydriatic retinal cameras and non-mydriatic retinal cameras are known as devices for imaging a fundus image by imaging reflected light from the fundus illuminated by light from a light source. In a pupil-type fundus camera, infrared light is used as a fundus illumination light source at the time of observation, so that it is not necessary to dilate the subject's eye like a mydriatic-type fundus camera, and is often used. In such a non-mydriatic retinal camera, the angle of view is not as wide as that of the mydriatic type, and imaging is performed mainly on the macula of the fundus, and alignment and focusing are performed using the infrared light focus index or alignment index. This is done by projecting onto the fundus.

[0003]

In a conventional fundus camera, light is incident from the pupil of the eye to be examined, and at the same time, fundus observation or photographing light is extracted from the pupil. In this case, since the incident light is reflected at the pupil portion and interferes with the reception of the photographing light, a ring slit or a diaphragm is inserted at the pupil conjugate position, the pupil portion is optically divided into two parts, and the fundus is cut through the ring slit. The pupil is illuminated from the periphery and the photographic light is extracted from the center of the pupil. For this reason, since a certain area is required for each of the divided parts, the minimum value of the pupil diameter that can be photographed is limited, and a non-mydriatic retinal fundus that performs imaging with a small pupil diameter without a mydriatic pupil There is a problem that a camera cannot capture a good fundus image.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve such a problem, and a fundus photographing apparatus capable of photographing a good-quality fundus image even in a non-mydriatic mode in which the pupil diameter is small. The task is to provide.

[0005]

In order to solve the above-mentioned problems, the present invention illuminates the fundus of a subject's eye with infrared light during observation,
At the time of imaging, in a fundus imaging apparatus that illuminates the fundus with visible light to photograph the fundus, an illumination optical system that illuminates the fundus by irradiating infrared light or visible light to the fundus through the sclera of the subject's eye,
An observation and photographing optical system for guiding reflected light from the fundus passing through the pupil of the eye to be examined to the fundus observation means or fundus recording means is employed.

In such a configuration, observation light and photographing light enter from the sclera (white eye portion) instead of the pupil of the eye to be examined, and reflected light from the fundus passes through the pupil to the fundus observation means or fundus recording means. Be guided. Therefore, even in the case of a small pupil diameter, reflected light from the fundus that passes through most of the effective diameter range of the pupil can be used for photographing, so that a wide-range image of the fundus can be photographed with good quality.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on an embodiment shown in the drawings.

FIG. 1A shows an optical system in which a fundus camera is viewed from above as an embodiment of a fundus photographing apparatus, and FIG.
(B) shows the optical system viewed from the side. In addition, in each figure, illustration is abbreviate | omitted about the part which illustration is difficult or impossible to overlap.

In FIG. 1A, the fundus Er of the eye E to be examined is shown.
Are provided with illumination optical systems 10 and 20 for illuminating. The illumination optical system 10 includes an illumination lamp 11, an infrared filter 12 that transmits only infrared light, a lens 13, a strobe 14, an aperture 15, and a lens 16. When the fundus is observed, light from the illumination lamp 11 After passing through the infrared filter 12, the light passes through the lens 13, the diaphragm 15, and the lens 16, passes through the sclera (white-eye portion) Ec of the subject's eye, irradiates the fundus Er, and the fundus Er is illuminated with infrared light. . In photographing the fundus, the strobe 14 emits light, and the fundus is illuminated with visible light.

In order to uniformly illuminate the fundus, the photographing optical axis C
Another illumination optical system 20 is arranged almost symmetrically with respect to the illumination lamp 2.
1. An infrared filter 22 that allows only infrared light to pass therethrough, a lens 23, a strobe 24, an aperture 25, and a lens 26. At the time of fundus observation, light from the illumination lamp 21
After passing through the infrared filter 22, the lens 23 and the aperture 2
5. The fundus Er passes through the sclera (white-eye portion) Ec of the subject's eye via the lens 26, and illuminates the fundus Er with infrared light. When photographing the fundus, the strobe 24 emits light and the fundus illuminates with visible light. Is done.

Each of the illumination optical systems 10 and 20 is configured to be able to approach or separate from the optical axis C with the fundus Er as a base point, and is configured to change the scleral portion through which the illumination light passes. .

The reflected light from the fundus Er illuminated by the above-described illumination optical systems 10 and 20 is received from the pupil Ep via the objective lens 30, and is substantially conjugated with the pupil Ep (the anterior segment of the eye to be examined). The lens is stopped down by a photographing stop 31 arranged at a position, passes through a focusing lens 32 and an imaging lens 33, and enters a mirror 34. The light reflected by the mirror 34 forms an image on a photographing CCD 35 having sensitivity to visible light, and the image is transmitted via a video switching device 37 to a video image recording device (means).
39.

The mirror 34 can be detached from the optical path. When the mirror 34 is detached, a fundus image is formed on an observation CCD 36 having sensitivity mainly to infrared light, and is switched by a video switching device 37. And is observed on the monitor 38.

Further, an infrared light source (light emitting diode) 40 for a focus index is provided, and light from this light source passes through a lens 41, a mirror 42, and a lens 43, and a photographing aperture 31.
Are divided and incident on mirrors 44 and 44 ′ disposed between the focusing lens 32 and a focusing spot image (focus index image) is formed on the fundus Er via the photographing diaphragm 31 and the objective lens 30. . The focusing lens 32 and the lens 43 can move along the optical axis in conjunction with each other. When the fundus is in focus, the divided spot images match, and the fundus images are CCDs 35 and 36, respectively. It is configured to focus on and image.

Further, alignment index light sources (light emitting diodes) 50 and 51 for generating infrared light are provided, and images of the light sources are formed on one end surfaces of the optical fibers 54 and 55 by lenses 52 and 53. The other ends of the optical fibers 54 and 55 are guided to the photographing diaphragm 31,
The image is projected on the eye E through the objective lens 30. Thereby, an alignment index image, that is, a working dot is formed on the eye to be inspected, and alignment with respect to the eye to be inspected is performed while observing the image of the working dot.

Further, the optical axis C of the optical system for observation and photographing is
An anterior ocular segment observation lens 60 to be inspected is disposed so as to be freely inserted and removed,
When the anterior ocular segment lens 60 is inserted into the optical axis C, the anterior ocular segment is in focus, and the monitor 38 can observe the image of the anterior ocular segment. Depending on the detachment or insertion of the lens 60 from the optical axis C, the amount of light of the observation illumination light sources (illumination lamps) 11 and 21 or the focus index light source 40 or the alignment index light source 5
It is configured such that the lighting and extinguishing of 0 and 51 or the light quantity thereof can be adjusted.

Next, the operation of the fundus photographing apparatus thus configured will be described.

At the time of fundus observation, first, the anterior ocular segment observation lens 60 is inserted into the optical axis C, and the illumination lamps 11 and 21 are turned on. At this time, the light source 40 for the focus index and the light sources 50 and 51 for the alignment index are turned off. The light from the illumination lamps 11 and 21 passes through the infrared filters 12 and 22 to become infrared light, passes through the sclera (white-eye portion) Ec of the subject's eye, and irradiates the fundus Er. Illuminated uniformly with light. This state is shown in FIG.

The image of the anterior segment at this time is picked up by the observation CCD 36 having sensitivity to infrared light by moving the mirror 34 out of the optical path, and the image shown in FIG. Observed in. The mark 70 indicates a position where the image center of the pupil Ep should be located, and the marks 71 and 72 indicate a position where the illumination light passes through the sclera Ec. As shown in FIG. Each mark position 70, 71, 7
The angle of the illumination optical systems 10 and 20 with respect to the optical axis C is adjusted so that the pupil image 74 and the illumination light images 73 and 73 'are observed in 2. In addition, since the observation CCD 36 has a little sensitivity to visible light, it is possible to observe an image of the anterior eye part other than the illumination light image.

Subsequently, the anterior ocular segment observation lens 60 is separated from the optical path, and the focus index light source 40 and the alignment index light sources 50 and 51 are turned on. At this time, since a fundus image illuminated with infrared light is formed on the observation CCD 36, an image as shown in FIG. 3B is observed on the monitor 38. Therefore, the focus index images 75 and 7
The focusing lens 32 is adjusted so that 5 ′ coincides with the mark 70, and alignment is performed so that the working dots 76 and 76 ′ are located within the marks 71 and 72.

As described above, when the fundus is uniformly illuminated and the alignment and focusing are completed, the light source 40 for the focus index, the light sources 50 and 50 for the alignment index are obtained.
1 is turned off, and each mark 70, 71, 7
2 is electrically turned off, for example, and the mirror 34 is moved to the position shown in FIG.
As shown in FIG.
4 are emitted synchronously. This time, the fundus Er is uniformly illuminated with visible light (photographing light), and the fundus image is narrowed by the diaphragm 31 to form an image on the photographing CCD 35 having sensitivity to visible light.
The image of the photographing CCD 35 is sent to the video image recording device 39 by the video switching device 37 and is recorded there. Note that the recorded fundus image can be displayed on the monitor 38 as well.

Since this fundus image passes through a large part of the effective diameter range of the pupil Ep as shown in FIG. 2B, even when the non-mydriatic type has a small pupil diameter, the reflection from the fundus is obtained. A large amount of light can be taken out, and the fundus image can be taken through the photographing aperture 31 through the photographing diaphragm 31 located at a position almost conjugate with the pupil.
Since the light enters the D35, it is possible to effectively block external light that is an obstacle, and it is possible to capture a bright and high-quality fundus image.

The fundus recording means includes a photographing CC.
It is also possible to use a means for optically recording the fundus image, for example, a photographic film, in addition to or in addition to the video image recording device 39 for magnetically recording the fundus image captured in D35.

If one illumination optical system 10 or 20 can uniformly illuminate the fundus, either one may be used, or two or more illumination optical systems may be provided. Good.

Further, the light amount of the observation illumination light sources 11, 21 or the light amount of the focus index light source 40 or the alignment index light sources 50, 51 is changed according to the insertion / removal of the eye observation lens 60. For example, when observing the anterior segment in which the anterior segment observing lens 60 is inserted, the light source for the focus indicator or the light source for the alignment indicator can be dimmed instead of being turned off. Further, the illumination lamps 11 and 21 can be increased in brightness when observing the fundus and the anterior segment, and can be dimmed or turned off during fundus photography.

[0026]

As described above, according to the present invention, the illumination light passes through the sclera portion of the eye to be examined and illuminates the fundus. Therefore, even when the pupil diameter is small, the effective pupil diameter range is small. The reflected light that passes through most of the image can be used for photographing, and a wide-range bright fundus image can be photographed with good quality.

[Brief description of the drawings]

FIG. 1A is an optical diagram showing an arrangement of an optical system when a fundus camera is viewed from above, and FIG. 1B is an optical diagram showing an arrangement of an optical system when the fundus camera is viewed from a side. FIG.

FIG. 2A is an explanatory diagram illustrating a state in which illumination light is incident on the fundus, and FIG. 2B is an explanatory diagram illustrating a state in which reflected light from the fundus exits through a pupil.

FIG. 3A is an explanatory diagram showing an image of an anterior eye part observed on a monitor, and FIG. 3B is an explanatory diagram showing a fundus image observed on a monitor.

[Explanation of symbols]

 10, 20 Illumination optical system 14, 24 Strobe 31 Photographing aperture 32 Focusing lens 35 Imaging CCD 36 Observation CCD 40 Light source for focus index 50, 51 Light source for alignment index

Claims (6)

[Claims] At the time of observation, the fundus of the eye to be examined is illuminated with infrared light,
A fundus imaging apparatus that illuminates the fundus with visible light when photographing to photograph the fundus, and an illumination optical system that illuminates the fundus by irradiating infrared light or visible light to the fundus through the sclera of the subject's eye, An observation and imaging optical system for guiding reflected light from the fundus passing through the pupil of the eye to be examined to a fundus observation means or a fundus recording means. 2. The fundus imaging apparatus according to claim 1, wherein a plurality of illumination optical systems are provided so as to sandwich an optical axis of the observation and imaging optical system. 3. The fundus photographing apparatus according to claim 1, wherein the photographing light sources arranged in the respective illumination optical systems emit light synchronously. 4. A diaphragm is disposed at a position substantially conjugate with the anterior segment of the eye to be examined in the optical system for observation and photographing, and reflected light passing through the pupil of the eye to be examined is derived through the diaphragm. The fundus photographing device according to claim 1. 5. The fundus photographing apparatus according to claim 1, wherein a lens for observing an anterior eye of an eye to be inspected is inserted into and detached from the observation and photographing optical system. 6. The method according to claim 1, wherein the amount of light of a light source for observation illumination or the amount of light of a light source for a focus index or an alignment index is changed according to insertion / removal of the anterior ocular segment observation lens. The fundus imaging apparatus according to any one of claims 1 to 7.