JP3896203B2 - Fundus camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fundus camera, and more specifically, irradiates light from an observation light source to the fundus of an eye to be examined via an illumination system, forms an image of reflected light from the fundus via an imaging optical system, and The present invention relates to a non-mydriatic retinal camera that observes the fundus of a subject's eye by branching an illumination system and an imaging optical system with a perforated total reflection mirror disposed at a position conjugate with the anterior ocular segment.
[0002]
[Prior art]
Generally, a mydriatic type fundus camera and a non-mydriatic type fundus camera are known as cameras for imaging a fundus image by forming an image of reflected light from the fundus illuminated by light from a light source. The mydriatic fundus camera mainly uses a light source of visible light, can capture a wide angle of view, and has a tilt mechanism of the camera itself, so that the entire fundus can be photographed. A drawback of this mydriatic retinal camera is that the subject's eye needs to be mydriatic and places a great burden on the subject.
[0003]
On the other hand, the non-mydriatic retinal camera is functionally inferior to the mydriatic retinal camera, but it uses infrared light as the observation light source, so there is no need to dilate the subject's eye and the burden on the subject Less is. Focus control is also performed by projecting an infrared light focus index onto the fundus without using visible light. This non-mydriatic retinal camera is widely used for mass screening because it does not use mydriatics, but it is necessary to make the room completely dark to use natural mydriasis. There is a demand for a fundus camera that can be more easily aligned (positioned) with the eye to be examined than a fundus camera.
[0004]
[Problems to be solved by the invention]
In a conventional fundus camera, an alignment detection index (working dot, hereinafter abbreviated as WD) is projected onto the subject's cornea in order to facilitate alignment with the subject's eye. In 61-90 and the like, this is done by inserting and removing an auxiliary lens for anterior segment observation. However, the method of performing alignment by projecting WD has a problem that it cannot be detected unless the position of the eye to be examined is in a considerably good state, and the method of inserting and removing the auxiliary lens has a problem of the anterior eye part (for example, iris). In order to perform alignment while looking at the focus state, there is a problem that the alignment accuracy is not good, and since the photographing system shares infrared light and visible light, there is a problem that a difference in focus occurs depending on the wavelength.
[0005]
Accordingly, an object of the present invention is to solve such problems, and to provide a fundus camera that can be easily aligned with the eye to be examined by simple means.
[0006]
[Means for Solving the Problems]
In order to solve this problem, the present invention
In a fundus camera that irradiates the fundus of a subject's eye with light from an observation light source and forms an image of reflected light from the fundus via an imaging optical system to observe the subject's fundus,
And alignment indicator is projected imaged the eye anterior segment when alignment between the eye and the retinal camera has been made,
An auxiliary optical system that is inserted into and removed from the imaging optical system and enables observation of the anterior ocular segment to be examined ;
A light source for anterior segment observation ,
The inserted auxiliary optical system to the imaging optical system, and turns on the light source for anterior segment observation, have row alignment based on the image of the alignment index of the eye anterior part observed, the at the time of the alignment A configuration was adopted in which the observation light source for irradiating the fundus was extinguished .
[0007]
According to such a configuration, when the eye to be examined and the fundus camera are aligned, the alignment index is imaged and projected on the anterior eye portion of the eye to be examined, so that the imaging state of the projected index image is observed. By doing so, it becomes possible to perform alignment easily and accurately.
[0008]
In the present invention, the anterior segment is illuminated with infrared light and the alignment index is illuminated with infrared light at the time of alignment, so that it can be easily applied to a non-mydriatic fundus camera.
[0009]
In addition, if the alignment index is divided and projected onto the anterior eye portion of the eye to be examined, not only the index image at the time of non-alignment is blurred, but also the alignment determination is facilitated because the image is separated, and the alignment accuracy is further improved. Can be improved. Also, if the alignment index is illuminated with different light sources and the light sources are driven in opposite phases, when the alignment is misaligned, the image will not only blur and separate into two, but the image will start blinking, further alignment It becomes possible to judge accurately.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail according to embodiments shown in the drawings.
[0011]
FIG. 1 shows a fundus camera according to the present invention. An observation light source 2 made of a halogen lamp or the like is arranged at the center of the mirror 1, and light emitted from the light source 2 passes through a condenser lens 3, a filter 4 and a mirror 5 to form a lens 6 and ring-shaped illumination. The light enters the ring slit 7. The filter 4 is an infrared filter that transmits only infrared light, and the mirror 5 is either a half mirror, a dichroic mirror (visible light transmission, infrared light reflection), or a return mirror (an insertable / removable mirror). Composed.
[0012]
The light beam that has passed through the ring slit 7 subsequently passes through the relay lens 8 and is arranged at a position conjugate with the anterior eye portion of the eye to be examined via the black spot plate 9 for reflecting the objective lens, the return mirror M1, and the lens 10. After being reflected by the perforated total reflection mirror 11, it passes through the objective lens 12 and enters the fundus Er from the pupil (iris) Ep of the eye E to be examined.
[0013]
The reflected light from the fundus Er is again received from the pupil Ep through the objective lens 12, passes through the focusing lens 16 and the imaging lens 17 through the hole of the perforated total reflection mirror 11, and enters the return mirror 18. . The light reflected by the return mirror 18 passes through a field stop (mask) 19 placed at the focus position, then forms an image on an image pickup device 23 such as a CCD via a field lens 20, a mirror 21, and a lens 22, and is monitored. M is observed by the examiner.
[0014]
When it is desired to take a fundus image on a film, the strobe 14 placed at the center of the mirror 13 emits light, and the fundus Er is illuminated through the condenser lens 15 and the mirror 5 in the same manner as described above. Then, the return mirror 18 is removed from the optical path, and a fundus image is taken on the film F.
[0015]
Further, an anterior lens L1 auxiliary lens L1 is disposed between the perforated total reflection mirror 11 and the objective lens 12 so that it can be inserted into the optical path or removed from the optical path. An infrared light source 50 for observing the eye part is disposed, and a light source 30 for projecting an alignment index and an alignment index 31 including a pinhole are provided. The position of the index 31 is set so as to form an image on the anterior eye portion of the eye to be examined, that is, the pupil (iris) Ep of the eye to be examined via the auxiliary lens L1 when the alignment of the eye to be examined and the apparatus is correct. That is, when the auxiliary lens L1 is inserted, the anterior segment of the eye to be examined becomes conjugate with the observation surface instead of the fundus so that the imaging state of the alignment index imaged on the pupil (iris) Ep of the eye to be examined can be observed. Become.
[0016]
In such a configuration, when performing alignment with the eye to be examined in measurement, that is, when performing alignment, the auxiliary lens L1 for observing the anterior segment that was detached from the optical path in FIG. It is inserted into the optical path, the infrared light source 50 for observing the anterior segment is turned on, and the eye E is illuminated. At the same time, the light source 30 for projecting the alignment index is turned on to illuminate the alignment index 31 composed of a pinhole or the like. At this time, the return mirror M1 is inserted into the optical path.
[0017]
The light emitted from the index 31 is reflected by the return mirror M1, reflected by the perforated total reflection mirror 11 having a hole in the center through the lens 10, and then the auxiliary lens L1 for observing the anterior segment and the objective lens 12. Then, an image is formed on the pupil (iris) Ep of the eye to be examined. At this time, when the alignment between the eye to be examined and the apparatus is correct, the position of the index 31 is set so as to form an image on the pupil (iris) Ep of the eye to be examined. As shown in FIG. 3A, an image 31a of the index 31 for alignment is observed in focus on M. On the other hand, when the alignment is shifted, the image 31b of the index 31 for alignment is blurred as shown in FIG.
[0018]
Since the index 31 is imaged on the iris Ep of the eye to be examined, the light source 30 for projecting the index for alignment does not affect the eye to be examined even with visible light, but is incident on the eye fundus Er when the alignment is adjusted. Infrared light is preferable. During alignment, the light from the light source 2 is reflected off the surface of the auxiliary lens L1 and the objective lens 12 and becomes harmful light, so it is turned off. After the alignment is correctly performed in this manner, the auxiliary lens L1 for observing the anterior segment is removed from the optical path, the infrared light source 50 for illuminating the anterior segment is turned off, and at the same time, the light source 30 is turned off. The Thereafter, the fundus Er of the eye to be examined is observed on the monitor M or photographed on the film F as necessary.
[0019]
Next, a method for further improving the alignment accuracy will be described. In order to increase the alignment accuracy, means for dividing the light beam into two is provided in the middle of the optical system for projecting the alignment index. For example, as shown in FIG. 4, when a configuration is adopted in which only the hatched portions 35 and 35 'in the figure are reflection surfaces on the return mirror M1, the light emitted from the alignment index 31 is reflected by the mirror M1. As shown in FIG. 5 (view of the apparatus from above), the light beam is also divided into two parts in the objective lens 12 so as to be focused for the first time on the pupil (iris) Ep of the eye to be examined. Become.
[0020]
Since the alignment index 31 is set to focus on the pupil (iris) of the eye to be examined when the alignment is correct, the index image 31a is as shown in FIG. 6A when the alignment is correct. And focus on the eye iris Ep. In addition, when the alignment is shifted, as shown in FIG. 6B, the index image is separated into two images 31c and 31d on the iris, and the focus is further blurred, so that the alignment accuracy is improved. In FIG. 4, if the surfaces of the mirror M1 other than the hatched portions 35 and 35 'in the drawing are made opaque, the harmful light from the light source 2 at the time of alignment is cut here, so it is necessary to turn off the light source 2. Disappears.
[0021]
FIG. 7 shows still another embodiment. In the figure, two light sources (LED1 and LED2) for projecting the alignment index 31 are used, and the light sources LED1 and LED2 are blinked in opposite phases. In this way, when the alignment is shifted, the index images 31c and 31d are separated into two as shown in FIG. 6B, and the image is separated, and the separated index images blink in opposite phases. To start. Of course, when the alignment is correct, the phases are interpolated with each other, so it looks like continuous lighting even if it is actually flashing. With such a configuration, the alignment accuracy can be further improved.
[0022]
Further, FIG. 8 shows another embodiment. In this embodiment, a light source 40 for projecting an alignment index, an alignment index 41 including a pinhole, a lens 42, and a mirror M2. Is arranged between the perforated total reflection mirror 11 and the focusing lens 16. As in the embodiment of FIG. 1, during alignment, an auxiliary lens L1 for observing the anterior segment is inserted into the optical path, and the infrared light source 50 for illuminating the anterior segment is turned on to illuminate the eye E. At the same time, the light source 40 for projecting the alignment index is turned on.
[0023]
The light emitted from the light source 40 for projecting the alignment index illuminates the alignment index 41, passes through the hole portion of the perforated total reflection mirror 11 via the lens 42 and the mirror M2, and then passes through the front. After passing through the auxiliary lens L1 for observing the eye part, the subject is focused on the pupil (iris) Ep of the eye through the objective lens 12. As in the previous embodiment, the alignment index 41 is set so as to focus on the iris Ep when the alignment between the eye to be examined and the apparatus is correct, so that the focus is blurred when the alignment is shifted. As a result, the alignment between the eye to be examined and the apparatus can be accurately determined.
[0024]
Further, in this embodiment, as shown in FIG. 9, the light beam may be divided into two by using the mirror M2 as the reflection surfaces 36 and 36 ′. In the mirror M2, shaded portions in the figure are reflective surfaces 36 and 36 ', and a light beam for photographing passes between the reflective surfaces. In this embodiment, the mirror M2 may not be separated from the optical path like the mirror M1. However, in this example, the harmful light from the light source 2 during alignment is not cut, so the light source 2 is turned off during alignment. Since functions and effects of the invention are the same as those of the above-described embodiment, detailed description thereof is omitted.
[0025]
Further, the splitting of the light beam by the mirror M2 may be performed by providing a mirror M2 ′ separated by a predetermined interval, as shown in FIG. With this configuration, the same effect as the configuration of FIG. 9 can be obtained.
[0026]
【The invention's effect】
As described above, in the present invention, when the eye to be examined and the fundus camera are aligned, the alignment index is imaged and projected on the anterior eye portion of the eye to be examined. By observing, it becomes possible to perform alignment easily and accurately.
[Brief description of the drawings]
FIG. 1 is an optical diagram showing a schematic configuration of a fundus camera according to an embodiment of the present invention.
2 is an optical diagram showing a state when alignment is performed with the configuration of FIG. 1; FIG.
FIG. 3 is an explanatory diagram showing an image observed on a monitor during alignment.
FIG. 4 is a configuration diagram showing a configuration in which an alignment light beam is divided into two.
FIG. 5 is an explanatory diagram showing an alignment light beam directed to the eye when the alignment light beam is divided into two.
FIG. 6 is an explanatory diagram showing an image observed on a monitor when an alignment light beam is divided into two.
FIG. 7 is a configuration diagram showing another configuration for dividing an alignment light beam into two.
FIG. 8 is an optical diagram showing a schematic configuration of a fundus camera according to another embodiment of the present invention.
9 is a configuration diagram showing a configuration in which the alignment light beam is divided into two in the configuration of FIG. 8. FIG.
10 is a configuration diagram showing another configuration in which the alignment light beam is divided into two in the configuration of FIG. 8. FIG.
[Explanation of symbols]
2 Observation light source 11 Perforated total reflection mirror 12 Objective lens 30 Alignment light source 31 Alignment index 50 Infrared light source L1 for observing the anterior segment E1 Auxiliary lens for observing the anterior segment E Subject eye Ep Eye of the subject eye ( iris)
Er eye fundus

Claims (7)

In a fundus camera that irradiates the fundus of a subject's eye with light from an observation light source via an illumination system and forms an image of reflected light from the fundus via an imaging optical system to observe the subject's fundus.
And alignment indicator is projected imaged the eye anterior segment when alignment between the eye and the retinal camera has been made,
An auxiliary optical system that is inserted into and removed from the imaging optical system and enables observation of the anterior eye portion to be examined ;
A light source for anterior segment observation ,
The inserted auxiliary optical system to the imaging optical system, and turns on the light source for anterior segment observation, have row alignment based on the image of the alignment index of the eye anterior part observed, the at the time of the alignment A fundus camera characterized by turning off an observation light source for irradiating the fundus.   The fundus camera according to claim 1, wherein the auxiliary optical system is inserted into and removed from a portion where the imaging optical system is shared with the illumination system.   The fundus camera according to claim 1, wherein the alignment index is illuminated with infrared light.   The fundus camera according to any one of claims 1 to 3, wherein the anterior ocular segment to be examined is illuminated with infrared light during alignment.   The fundus camera according to any one of claims 1 to 4, wherein the alignment index is divided and projected onto the anterior eye portion of the eye to be examined.   The fundus camera according to any one of claims 1 to 5, wherein the alignment index is illuminated by different light sources.   The fundus camera according to claim 6, wherein the different light sources are driven in mutually opposite phases.

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