JP2002125934A - Fundus camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To observe and photograph an eyeground in as wide range as possible by reducing the miosis of a eye to be checked due to the light of an internal fixation lamp. SOLUTION: The internal fixation lamp 36 is provided as a visual-mark which is visible by a patient for fixing the photographing range of the eye to be checked and its light is introduced to an illumination optical system via a dichroic mirror 30, a focus lens 34 and a dichroic mirror 35. The conjugate position R of the eyeground of the eye to be checked is defined at a prescribed position by the lens 34 linked with the focus lenses 12 and 13 of a photographing system when the photographing system is focused. The lamp 36 is arranged on the side of a distant point compared with this position, thereby the mydriasis of the eye to be checked is caused to suppress the influence of the miosis of the eye to be checked due to lighting of the lamp 36. By placing the lamp 36 in rear of the lens 34, offset from the position R of the lamp 36 becomes constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus camera provided with a visual target which can be visually recognized by an examinee in a main body optical system in order to fix an imaging range of an examinee's eye.

[0002]

2. Description of the Related Art In a fundus camera, when observing / photographing the fundus of an eye to be examined, an internal fixation lamp (fixation target or simply a target) is used to select a necessary part of the fundus. A technique for guiding the eye gaze of an optometry is known. The internal fixation lamp is usually arranged at a position conjugate with the fundus of the subject's eye so that the subject can visually recognize the subject during the alignment (alignment between the fundus camera and the subject's eye).

[0003]

On the other hand, in recent years, non-mydriatic cameras capable of observing / photographing the fundus without using a mydriatic agent have been widely known. A non-mydriatic camera does not use a mydriatic agent, so if the mydriatic state of the subject's eye is poor, the overall image will be dark or a shadow will be formed at the center of the fundus image, resulting in a good fundus image. Can not shoot.

In a non-mydriatic camera, turning on the internal fixation light of visible light and projecting it on the fundus may adversely affect the mydriatic state.

An object of the present invention is to reduce miosis of an eye to be examined due to light from an internal fixation lamp so that observation and photographing of the fundus as good as possible can be performed.

[0006]

According to the present invention, there is provided, in accordance with the present invention, a target which can be visually recognized by a subject in a main body optical system in order to fix a photographing range of an eye to be examined. In the fundus camera, the target is projected onto the eye to be examined through a focusing lens of the main body optical system or a lens interlocked with the focusing lens, and the main body optical system is focused on the fundus of the eye to be examined by a predetermined focus. A configuration is adopted in which the optotype is arranged at a far point side from the conjugate position of the fundus of the eye to be examined when adjusted to the state.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. Hereinafter, embodiments of a non-mydriatic retinal camera and a non-mydriatic / mydriatic retinal camera will be described.

[First Embodiment] FIG. 1 shows the configuration of a non-mydriatic retinal camera employing the present invention. In the figure, light emitted from a lamp 1 as a light source for observation passes through an infrared filter 2, a condenser lens 3, and a strobe 4 as a light source for photographing, and illuminates a ring slit 6. The ring slit 6 has a predetermined outer diameter and inner diameter, and forms an annular illumination light beam at a position substantially conjugate with the pupil Ep of the eye E to be examined.

The luminous flux from the ring slit 6 passes through a black spot plate 8 for removing reflection from the objective lens 11. The black spot plate 8 is a photographic stop 1 formed in the objective lens 11.
Black point 8 arranged at a position substantially conjugate to the reflection virtual image 11a of FIG.
a.

The light beam passing through the black spot plate 8 passes through a dichroic mirror 35, and is reflected by a perforated total reflection mirror 10 having a hole at the center through a relay lens 9. The light beam reflected by the total reflection mirror 10 is imaged by the objective lens 11 on the pupil Ep of the eye E to be examined, and then enters the fundus Er to illuminate the fundus almost uniformly with infrared light. The dichroic mirror 35 is configured as an infrared half mirror and reflects about 25% of the visible light component and about 50% of the infrared light component.

The reflected light from the fundus Er passes through the center of the pupil Ep again, is received via the objective lens 11, and is disposed on the optical path of the photographing optical system via the hole of the perforated total reflection mirror 10. Shooting aperture 14, focus lens 12, 1
3. The light passes through the imaging lens 15 and enters the return mirror 16.

The light beam from the fundus reflected by the return mirror 16 is condensed by an imaging lens 17 onto an observation camera 19 having an infrared filter 18 disposed on the front. The imaging device (CCD or the like) of the observation camera 19 has sensitivity to infrared light. The fundus image photographed by the observation camera 19 is recorded on the video device 20 and reproduced on the monitor 21 connected to the video device 20 so that the examiner can observe the image.

Behind the return mirror 16, an imaging lens 22 and a photographing camera 23 sensitive to visible light
Is arranged. The photographing camera 23 is likewise a video device 2
Connected to 0. At the time of fundus photographing, the return mirror 16 is separated from the optical path, and the image taken by the photographing camera 23 is recorded by the video device 20 and can be displayed on the monitor 21.

In order to form a focus dot on the fundus for focusing, a focus index 31 having a small hole 31a at the center is provided. The focus index 31 is transmitted through the image prism 32 to the infrared L
Illuminated by the ED 33, the dichroic mirror 30,
Dichroic mirror 3 via focus lens 34
After being reflected at 5, the light is combined with the light beam of the illumination optical system, the focus index 31 is projected on the fundus Er, and a focus dot is formed. The focus lens 34 is linked with the focus lens 13 via a link mechanism (not shown).

Further, in the present embodiment, in order to guide the line of sight of the subject's eye and fix the photographing range of the subject's eye, an internal fixation lamp 36 is provided in the main body optical system as a visual target that can be visually recognized by the subject.
Is provided.

The internal fixation lamp 36 comprises an LED 36a of a predetermined color (green or the like) and a small-diameter hole plate 36b, and the light (visible light) is reflected by a dichroic mirror 35 of infrared transmission and reflection, and a focus lens. The light is guided toward the subject's eye via 34.

At the time of observation / photographing, the focus lenses 12 and 13 are moved using the image of the focus index 31, as described later, to adjust the main body optical system to a predetermined in-focus state.

When this in-focus state is obtained, the fundus conjugate position R (conjugate position with the fundus R0) conjugated to the fundus Er of the eye E to be examined with respect to the body optical system including the focus lenses 12 and 13 is the focus index 31. Position and fundus conjugate position R
And also coincides with the imaging surface (CCD or the like) of the observation camera 19.

Conventionally, the internal fixation lamp 36 is usually arranged at the fundus conjugate position R, but in this embodiment, it is installed at a position slightly offset from the fundus conjugate position R to the far point side. I do.

This is because it is known that a human naturally has a slight mydriasis when trying to gaze at a distant point. Therefore, as in the present embodiment, the internal fixation lamp 36 is slightly smaller than the fundus conjugate position R. By arranging it on the far point side, the internal fixation lamp 3
It is possible to suppress the effect of miosis caused by the lighting of No. 6.

Since the diopter of the eye E to be examined varies from person to person, the position of the internal fixation lamp 36 is set to a point farther than the conjugate position R of the fundus and the above-mentioned effect of preventing miosis is obtained. When projecting the internal fixation lamp 36 to the fundus, it is necessary to pass through a focus lens or a lens interlocked with the focus lens (in this embodiment, the focus lens 34 interlocked with the focus lenses 12 and 13).

In other words, by projecting the internal fixation lamp 36 onto the fundus through the focusing optical system as in the present embodiment, a predetermined focusing operation can be performed even if the diopter of the eye E changes. If performed, the fundus conjugate position R is adjusted to each position in the figure, and the offset of the internal fixation lamp 36 from the fundus conjugate position R is always constant.

When the internal fixation lamp 36 is located far away from the fundus conjugate position R, the examinee cannot visually recognize the internal fixation lamp 36. Therefore, the internal fixation lamp 36 is moved from the fundus conjugate position R on the optical axis. It is preferable to keep a distance corresponding to about 5D apart.

In the above configuration, at the time of fundus observation, the lamp 1 is turned on, and the luminous flux from which the wavelength range of the infrared light is extracted by the infrared filter 2 is supplied to the condenser lens 3, the ring slit 6, the black spot plate 8, the dichroic mirror. 35, reflected by the perforated total reflection mirror 10 through the relay lens 9,
After passing through the pupil Ep of the eye E to be examined, the light enters the fundus Er and illuminates the fundus with infrared light. The reflected light from the fundus Er is:
The light passes through the center of the pupil Ep, is received through the objective lens 11, passes through the hole of the perforated total reflection mirror 10, passes through the photographing aperture 14, the lenses 12, 13, and 15, and is reflected by the return mirror 16, Observation camera 1 by imaging lens 17
The fundus image is collected by an observation camera 19 having sensitivity to infrared light. The fundus image photographed by the observation camera 19 is recorded on the video device 20, and the video device 2
It is reproduced on the monitor 21 connected to the monitor 0 and observed by the examiner.

At the time of this observation, the infrared LED 33 is also turned on at the same time, the focus index 31 is illuminated via the image prism 32, and the infrared light passing through the small hole 31a of the focus index 31 passes through the dichroic mirror 30 and the focus lens 34. The light is then reflected by the dichroic mirror 35, combined with the illumination light, and projected as a focus dot on the fundus Er. When the focus dot is out of focus on the fundus, the focus dot is observed on the monitor 21 as an unclear dot. However, when the focus lens 13 is adjusted, the focus lens 34 is adjusted in conjunction therewith,
It will be observed as a clear focus dot.
When a clear focus dot is observed, the fundus image is also focused on the photographing optical system, so that the examiner adjusts the focus dot reflected on the monitor 21 by adjusting the focus lens 13. By setting the state, it is possible to focus on the fundus.

When the focusing is completed, a fundus is photographed by pressing a shutter (not shown). At this time, the dichroic mirror 35 moves perpendicularly to the drawing and deviates from the optical path, and the return mirror 16 also separates from the optical path and the strobe 4 emits light at the same time. Therefore, the fundus image illuminated by the strobe 4 is 11, the hole of the total reflection mirror 10, the photographing aperture 14, the lenses 12, 13,
The images are photographed by the photographing camera 23 through 15 and 22. The fundus image photographed by the photographing camera 23 is recorded on the video device 20 and can be displayed on the monitor 21.

In order to guide the line of sight of the eye E, the internal fixation lamp 36 is turned on. The visible light of the internal fixation lamp 36 is reflected by the dichroic mirror 30, enters the dichroic mirror 35, and thereafter travels to the eye E along the same path as the focus index. As described above, in the case of the present embodiment, since it is located slightly far from the fundus conjugate position R, the mydriasis of the eye to be examined is induced, and the influence of the miosis caused by the lighting of the internal fixation lamp 36 of visible light. And obstruction of the observation or imaging field of view can be prevented, and a good fundus image can be obtained.

In the present embodiment, the internal fixation lamp 36 is projected onto the fundus through the focusing optical system (focus lens 34). Therefore, even if conditions such as the diopter of the eye to be examined fluctuate. By performing a predetermined focusing operation, in the present embodiment, it is possible to position the retinal conjugate position R on the far point side by a predetermined distance from the fundus conjugate position R. Can be obtained almost equally.

[Second Embodiment] Although the embodiment of the non-mydriatic retinal camera has been described above, the present invention is of course applicable to a non-mydriatic pupil and pupil retinal camera which switches between mydriatic and mydriatic methods. Can be implemented. In the case of such a non-mydriatic mydriatic device, control is performed so that the internal fixation lamp is turned on only during the observation of the fundus in the non-mydriatic mode, and is turned off during the observation of the fundus in the mydriatic mode.

FIG. 2 shows the arrangement of the optical system of the fundus camera according to the present embodiment. As shown, a lamp LA that emits light in the visible and infrared regions is arranged at the center of a mirror M1 and emitted from this lamp. The light is a condenser lens L
1. The light is reflected by the total reflection mirror M2 through the filter F1 or the filter F1 ′, the condenser lens L2, and subsequently through the ring slit unit 53 or the ring slit unit 54, the black spot plate 8 and the dichroic mirror 35 similar to the above embodiment, After being reflected by the perforated total reflection mirror M3, the light is incident on the fundus Er from the pupil Ep of the eye E through the objective lens L5.

Of the above, the filter F1 is an infrared filter that passes only infrared light or near-infrared light, and the filter F1 ′ is an infrared cut filter, which is switched according to non-mydriatic / mydriatic mode. Used.

The ring slit units 53 and 54 are for forming different ring-shaped illumination light in the non-mydriatic / mydriatic mode, respectively.

The dichroic mirror 35 is for arranging the projection system of the focus index and the internal fixation lamp as in the above embodiment, and reflects about 25% of the visible light component and about 50% of the infrared light component. . Behind the dichroic mirror 35, a focus lens L6 'interlocked with the focus lens L6 is arranged.

A dichroic mirror M8 that transmits infrared light and reflects visible light is disposed behind the focus lens L6 '.

The light (infrared light) of the focus index LED 58 used in the non-mydriatic mode passes through the mirror M8 via the image prism 57 and the focus index 61.

The light (visible light) of the focus index LED 56 used in the mydriatic mode is reflected by the dichroic mirror M8 via the image prism 55, the focus index 61, and the half mirror M9.

The light (visible light) of the internal fixation lamp 59 used only when the pupil does not pass through the half mirror M9 and travels to the dichroic mirror M8.

The internal fixation lamp 59 is composed of an LED 59a and a small-diameter hole plate 59b. In this embodiment, the internal fixation lamp 59 is also located slightly far from the fundus conjugate position R.

In FIG. 2, the fundus Er of the eye to be examined is also shown.
A fundus conjugate position conjugate with (R0) is indicated by a symbol R,
Focus indicators 60 and 61, film, observation camera 1
9. The imaging surfaces of the photographing camera 23 and the like are respectively arranged at the fundus conjugate positions R.

An external fixation lamp 51 is provided near the objective lens L5 to guide the line of sight of the eye E during mydriasis.

The reflected light from the fundus Er is received again from the pupil Ep via the objective lens L5, and is passed through the hole of the perforated total reflection mirror M3 and the photographing aperture 14 to obtain the focus lens L.
6. The light passes through the imaging lens L7 and enters the mirror M4.
The mirror M4 is a return mirror, and can be flipped up to guide the fundus image to the film 52 at the time of photographing.

The light reflected by the mirror M4 is transmitted to a lens L8.
Pass through the mirror M5. The mirror M5 is also a return mirror, and is in an inserted state during observation in the mydriatic mode, so that the examiner S can observe a fundus image via the mirror M5 and the lens L8.

When the mirror M5 is flipped up, the light reflected by the mirror M4 via the lens L10 reaches the position of the mirror M6. The mirror M6 is also a return mirror, and converts the fundus image from the lens L9 to the infrared filter 1.
It is for guiding in any direction from 8 to the observation camera 19 or the photographing camera 23.

Observation camera 19 or photographing camera 23
The fundus image taken at is input to the video device 20,
It can be observed on the monitor 21.

In the above configuration, when the apparatus is switched to the non-mydriatic mode, the infrared filter F 1 is inserted, and the ring slit is switched to the ring slit unit 53.

In the non-mydriatic mode, the LED 58 of the infrared light is turned on as the LED of the focus index, and the internal fixation lamp 59 of the visible light is turned on. Since the internal fixation lamp 59 is disposed slightly far from the fundus conjugate position R, the influence of the miosis caused by the turning on of the visible light internal fixation lamp 59 is similar to the first embodiment. It is possible to suppress the obstruction of the observation or photographing visual field and obtain a good fundus image.

Also in this embodiment, since the internal fixation lamp 59 is projected onto the fundus through the focusing optical system (focus lens L6 '), conditions such as the diopter of the eye to be examined change. However, if a predetermined focusing operation is performed, in the present embodiment, the eye can be positioned a predetermined distance away from the fundus conjugate position R by a predetermined distance. The effects can be obtained almost equally.

On the other hand, when the apparatus is switched to the mydriatic mode, the filter F1 is switched to the infrared cut filter F1 ', and the ring slit is also switched to the ring slit unit 54. In the mydriatic mode, the internal fixation lamp 59 is turned off and the external fixation lamp 51 is turned on, and the external fixation lamp 51 guides the line of sight of the eye E to be examined. I do.

According to this embodiment, according to the switching of the operation mode, ie, the switching of the wavelength of the illumination light at the time of fundus observation in the non-mydriatic / mydriatic mode, insertion / removal of the necessary filter and ring slit unit. And turning on / off the target, especially the internal fixation lamp, according to the wavelength characteristics of the illumination light during observation, so that the optical system can be shared with other targets (such as focus targets). , Can be used selectively.

Note that the fundus observation / photographing operation in the mydriatic mode / non-mydriatic mode is almost the same as in the first embodiment, and a detailed description is omitted here.

Although the two embodiments have been described above, in any of the embodiments, the internal fixation lamp is disposed in an optical system divided by a mirror from the illumination optical system. However, the internal fixation lamp may be arranged behind the focusing lens (the focus lenses 12 and 13 in the first embodiment, and the focus lens L6 in the second embodiment).

[0052]

As is apparent from the above description, according to the present invention, a fundus camera provided with an optotype visible in the main body optical system in order to fix the photographing range of the eye to be inspected in the main body optical system. The target is projected onto the eye to be examined via a focusing lens of the main body optical system or a lens interlocked with the focusing lens, and the main body optical system is adjusted to a predetermined focusing state with respect to the fundus of the eye to be examined. Since the configuration in which the optotype is arranged on the far point side from the fundus conjugate position of the eye to be examined at the time of being suppressed, the influence of miosis caused by turning on the light source of the index is suppressed, and observing or narrowing of the imaging visual field is prevented. A good fundus image can be obtained. Also, since the target is projected to the fundus through the focusing optical system, the target is projected through a focusing lens or a lens linked thereto. So that the eye Even if the conditions of the eye and the like fluctuate, if the predetermined focusing operation is performed, it can always be positioned at a far point side from the fundus conjugate position by a predetermined distance. An excellent effect that the pupil prevention effect can be obtained almost uniformly can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a non-mydriatic retinal camera employing the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a fundus camera of a mydriatic / non-mydriatic switching type employing the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lamp 2, 18 Infrared filter 3 Condenser lens 4 Strobe 6 Ring slit 8 Black spot plate 9 Relay lens 10 Perforated total reflection mirror 11, L5 Objective lens 12, 13 Focus lens 14 Shooting aperture 15 Imaging lens 16 Return mirror 17 Image lens 19 Observation camera 20 Video device 21 Monitor connected to video device 20 23 Camera for shooting 30 Dichroic mirror 31, 60, 61 Focus indicator 31a Small hole 32, 55, 57 Image prism 34, L6, L6 'Focus lens 35, M8 Dichroic mirror 36, 59 Internal fixation light 51 External fixation light 53, 54 Ring slit unit E Eye to be examined F1, F1 'Filter L1, L2 Condenser lens L7 Imaging lens L10 Lens LA La Flop 33 infrared LED 56, 58 focus index LED M1, M4, M5 mirror M2 total reflection mirror M3 apertured total reflection mirror M9 half mirror R fundus conjugate position

Claims (4)

[Claims] 1. A fundus camera in which a target which can be visually recognized by a subject is provided in a main body optical system in order to fix an imaging range of an eye to be inspected, wherein the target is a focusing lens or a focusing lens of the main body optical system. Along with being projected onto the eye to be examined via a lens interlocked with a focusing lens, the main body optical system is positioned farther from the fundus conjugate position of the eye to be examined when the predetermined focusing state is adjusted with respect to the fundus of the eye to be examined. The fundus camera according to claim 1, wherein a target is arranged. 2. The fundus camera according to claim 1, wherein the target is disposed in an optical system divided by a light dividing unit from an illumination optical system in the main body optical system. 3. The fundus camera according to claim 1, wherein turning on or off of a light source for the target is controlled in accordance with switching of an operation mode. 4. The method according to claim 1, wherein the switching of the operation mode is switching of the wavelength of illumination light during fundus observation, and controlling turning on or off of the light source for the target in accordance with the switching of the wavelength of the illumination light. The fundus camera according to claim 3, characterized in that: