JPS63164938A - Eyeground 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 enables observation of the anterior segment of the eye to align the position of the eye to be examined, and makes it possible to guide the line of sight of the eye to be examined during observation of the anterior segment of the eye. This relates to a fundus camera.

[Prior Art] Japanese Patent Publication No. 52-48440 by the applicant of the present invention discloses a fundus camera capable of observing the anterior segment of the eye to be examined using the same observation finder in order to align the eye to be examined. Are known. To explain this proposal according to FIGS. 6(a) and 6(b), illumination light from an illumination system (not shown) is reflected by a perforated mirror L and moves to the left, and an objective lens placed opposite the eye E to be examined. 2 and enters the eye E to be examined. The light flux reflected by the fundus Ef of the eye E to be examined is configured to pass through the objective lens 2 to the right, pass through the perforated mirror 1, and form an image on the film surface 4 via the relay lens 3 provided behind it. There is. A movable mirror 5 that can be raised and lowered is provided between the relay lens 3 and the film surface 4. When the movable mirror 5 is inserted into the optical path, the reflected light is reflected upward and the light deflection mirror 6 It reaches the finder eyepiece lens 7 via.

Fundus Ef and pupil E in this optical system for fundus observation/photography
To explain the image formation relationship of p in more detail, in FIG. 6(a), the illumination light from the illumination system forms a light source image on the aperture 1a of the perforated mirror 1, and then passes through the objective lens 2 to the illumination light. An image is formed on the pupil Ep plane of the optometrist E to illuminate the fundus Ef. When the device is in the proper position relative to the eye E, [lii!
Ep is the aperture 1 of the perforated mirror 1 by the objective lens 2.
The image is formed on a. The examiner should check the rear focal plane position R of objective lens 2.
The image of the fundus Ef formed on the lens 1 is focused on the film surface 4 by the relay lens 3 through the opening 1a of the perforated mirror 1. At this time, if a movable mirror 5 is inserted into the optical path, the light beam that should be incident on the film surface 4 is reflected upward by the movable mirror 5, and then reflected by the mirror 6 at a position equidistant from the film surface 4. A fundus image is connected to R2 and can be observed through the eyepiece lens 7.

At this time, the opening 1a of the perforated mirror 1 forms the entrance pupil of this optical system.

An auxiliary lens 8 is placed between the objective lens 2 and the perforated mirror 1.
is provided in the optical path so that it can be inserted and removed freely. When observing the anterior segment of the eye, this auxiliary lens 8 can be inserted into the optical path as shown in FIG. 6(b), and when it is not inserted, the objective lens 2 The pupil image formed at the 0 position R2', where the image of the pupil Ep is formed at the same position R2° as the position R2 where the image of the fundus Ef is formed, is the same as in FIG. 6(a). It is observed by the examiner through the eyepiece lens 7. Therefore, first insert the auxiliary lens 8 into the optical path, and then
to align the top, bottom, left and right of the pupil Ep, then adjust the auxiliary lens 8
is removed from the optical path, the fundus Ef is observed through the same eyepiece lens 7, and the movable mirror 5 is removed from the optical path to proceed to projection onto the film surface 4.

However, the subject does not know where to look when observing the anterior segment for pupil alignment, and it is not always possible to achieve accurate optical axis alignment between the eye E and the fundus camera after this alignment. The problem is that it cannot be done.

Further, a fundus camera is known in which the line of sight of the eye E to be examined is fixed by inserting an optotype plate in a position conjugate with the fundus Ef of the eye E to be examined in the observation optical system. In this case, the optotype plate 9 shown in FIG. 7 is placed at a position conjugate with the position R2 shown in FIG. 6, and is illuminated from behind by a light source. The shape of this optotype plate 9 has two small holes 9a and 9b eccentric from the optical axis, and one of the two light sources is selectively turned on depending on whether the eye E to be examined is the left eye or the right eye. and illuminates the small hole 9a or 9b. In other words, it is useful for diagnosis to normally take a fundus photograph in which the fixation point F of the eye E to be examined is slightly eccentric from the center of the screen, as shown in FIG. The light emitted from the small hole 9a or 9b is as shown in Fig. 6 (
It is projected toward the fundus Ef of the eye E to be examined through the optical system of a), and the line of sight of the eye E to be examined is fixed by the examinee gazing at the image of the small hole 9a or 9b. However, the sixth
In the optical system shown in Figure (b), the light flux emitted from the small holes 9a and 9b located at positions largely eccentric from the optical axis
Since it cannot pass through the pupil Ep of the eye, it has the disadvantage that it cannot be used to guide the line of sight when observing the anterior segment of the eye.

Japanese Patent Application Laid-Open No. 59-194729 is known as an improvement plan for these, and this known device has a second fixation target placed in the anterior segment observation optical system at a position conjugate with the fundus of the eye to be examined. By providing this, the above-mentioned drawbacks are solved. FIG. 9 shows an example of this, in which a minute light source 1O is arranged at a position R that is substantially conjugate with the fundus Ef in the auxiliary lens 8 in FIG. However, although this light source 10 and the wiring cord 11 for supplying power to the light source 10 are non-conjugate to the anterior eye segment that is currently being observed, they produce unpleasant shadows in the anterior eye segment image. .

[Object of the Invention] In consideration of the above-mentioned points, an object of the present invention is to provide a fundus camera that does not cause any inconvenience when observing the anterior segment of the eye and can guide the line of sight of the eye to be examined during the observation of the anterior segment of the eye. It is in.

[Summary of the Invention] The gist of the present invention for achieving the above-mentioned object is to provide an observation and photographing optical system for observing or photographing the fundus of the eye to be examined, and a system for observing and photographing the fundus of the eye to be examined by sharing at least a part of the observation and photographing optical system. A #Hattori observation optical system for observing the anterior eye segment for alignment is housed or attached to a housing, and a light is placed at a predetermined position outside the housing while the anterior eye segment is being observed using the anterior eye segment observation optical system. This is a fundus camera characterized by being provided with a luminescent optotype.

[Embodiments of the Invention] The present invention will be described in detail based on embodiments illustrated in FIGS. 1 to 5. It should be noted that the same numbers as in FIG. 6, such as the projection optical system and the anterior eye observation optical system lens 8, have the same functions, so the explanation will be omitted.

FIG. 1 is an external view of the fundus camera according to the present invention.
A light emitting element 20a with a color D is incorporated. FIG. 2 is a front view thereof, in which a light emitting element 20b is similarly provided at a position symmetrical to the optical axis of the objective lens 2. In Fig. 1, C is a film box with an eyepiece, and the position of the optical system after the movable mirror 5 and the light-emitting element 20a in which the film is stored is as shown in Fig. 3, which captures the standard fundus photographing range. Line of sight L1 guided to
0 light emitting element 20a installed on the approximate extension of E
By being observed by R, the line of sight L2 is guided, and the eye EL to be examined can also be naturally fixed substantially in the direction of Ll. At this time, the light emitting element 20b is in the shadow of the fundus camera body and cannot be observed by the subject.

FIG. 4 is a schematic diagram of the main body, and (a) is the fundus Ef.
(b) is a state in which the anterior segment of the eye is observed. In FIG. 4, a half mirror 21 is arranged in place of the optical path deflection mirror 6 of FIG. 6, and a hearth mirror 21 is placed behind it.
, the position equivalent to position R2, that is, the fundus E of the eye E to be examined.
An optotype board 9 is arranged at a position fiR3 conjugate with f, and fixation lights 22a and 22b are provided behind it. As shown in FIG. 7, the optotype plate 9 has two small holes 9a and 9b, and fixation lights 22a and 22b are provided corresponding to the respective small holes 9a and 9b. In addition, as mentioned earlier, the fixation lamp 2
2a and 22b are selectively turned on by the left and right eyes of the eye E to be examined, and are used, for example, to guide the line of sight Ll of the eye to be examined in the case of Figure S3 in which the eye E is the left eye EL. The light emitting elements 20a and 20b provided on the outer wall of the housing H of the fundus camera are
As shown in FIGS. 4(a) and 4(b), it has its own lighting switch 23, and is configured so that the switch 23 is turned on by a contact 8S attached to the auxiliary lens 8, and the light is turned on by a drive circuit 24. .

As shown in FIG. 4(b), when the auxiliary lens 8 is inserted and the anterior segment is observed, the light from the fixation lamp 22a or 22b is not observed in the eye E as described above. Approximate line-of-sight guidance is performed by the light-emitting element 20a or 20b, which can be observed depending on the details. In this state, the examiner
After roughly adjusting the position of the fundus camera body while observing the pupil Ep image, the apparatus is switched to the fundus observation state shown in FIG. 4(a). At this time, the light-emitting elements 20a and 20b are turned off by the action of the switch 23 mentioned above, but at the same time, the image of the small hole 9a or 9b of the optotype plate 9 can be observed through the objective lens 2, and this time it can be accurately observed. The line of sight of the eye E to be examined is fixed.

If the accommodation of the eye E to be examined is insufficient or there is strabismus, etc., the eye to be examined E may not be sufficiently guided to the line of sight Ll by guiding the line of sight L2 using the light emitting elements 20a and 20b. This is not a particularly important problem, since the amount of final optical axis adjustment is much smaller than if there was no prior line-of-sight guidance. Furthermore, for the same reason, if the light emitting elements 20a and 20b are left on, the subject will be in a state where it is difficult to decide which of the two fixation targets to fixate, so this is not necessary when observing the fundus. Although it is desirable to automatically turn off the light emitting elements 20a and 20b as in the example, this may be done manually.

In the previous embodiment, the light emitting elements 20a and 20b were provided on the outer wall of the housing H, which is the easiest way to construct the device, but there is no particular restriction on the position as long as the light emitting elements 20a and 20b can be observed from the opposite end of the photographing eye. Instead, it may be placed on the outer wall of the attached film box C or on a ball raised from the support of the housing H. It is necessary that it not move when adjusted for E. In addition, in order to eliminate the risk that the light emitting element 20 on the opposite side will be observed by the eye E when the fundus camera is adjusted and the housing H is moved significantly, the light emitting elements 20 are emitted corresponding to the left and right eyes of the eye E to be examined. Element 2
0a or 20b may be selectively turned on.

Furthermore, in the previous embodiment, the light emitting elements 20a and 20b were turned on by the switch 23 using the contact point 8S of the auxiliary lens 8, but when the auxiliary lens 8 is inserted and removed by electrical means such as TRUID, is one light emitting element 20a, 20b
The lighting may be performed in synchronization with the signal sent to the LED.

Further, the fixation lights 22a and 22b may be controlled by a liquid crystal shutter or the like.

Furthermore, during fundus observation, switching between the light-emitting elements 20a, 20b on the outside of the housing H and the fixation lights 22a, 22b inside the housing H can be switched on, if the fixation of the subject's eye E is unstable. This is effective because you can fix your line of sight by fixating on.

FIG. 5 shows another embodiment in which, instead of the light emitting elements 20a and 20b provided on the outer wall of the housing H, optotype plates 25a and 25b provided on the protruding portion H' are used as lamps 26a and 25b from behind.
, 26b, and lenses 27a, 27b (however, 25a, 26a, 27a are not shown) project the optotype plate image to infinity. Due to this,
The optotype plates 25a and 25b can also be observed without adjustment, similar to the internal optotypes. Here, in order to adjust the direction in which the line of sight is guided, it is possible to make the protrusion H° rotatable in the direction of the arrow, or to provide a mirror optical system at the tip of the lens 27b to achieve the same effect, thereby making it more reliable. You can guide your line of sight.

Further, in order to make the presentation distance of the optotype plate 25b variable in accordance with the diopter of the subject, it is also possible to move the lens 27b in the optical axis direction or to use a variable focus lens.

[Effects of the Invention] As explained above, the fundus camera according to the present invention can guide the line of sight of the eye to be examined even when observing the anterior segment of the eye by simply adding a very small additional part to the conventional device. Become. Furthermore, this improvement does not cause any problems and can be achieved at low cost. Furthermore, if the two light-emitting optotypes described above can be switched on and off, there is also the secondary effect that reliable line-of-sight guidance can be achieved even for the subject's eye whose fixation is unstable.

[Brief explanation of the drawing]

Drawings 1 to 5 show an embodiment of the fundus camera according to the present invention, in which Fig. 1 is an external view, Fig. 2 is a front view, Fig. 3 is an explanatory diagram of the position of the luminescent target, and Fig. 4 Figures (a) and (b) are configuration diagrams, Figure 5 is a configuration diagram of another embodiment, and Figure 6 (a).
), (b) is a block diagram of a conventional device, FIG. 7 is a front view of an optotype plate, FIG. 8 is an explanatory diagram of a standard fundus photographing range, and FIG. 9 is a block diagram of an auxiliary lens. Symbol 1 is a perforated mirror, 2 is an objective lens, 5 is a movable mirror, 7 is a confining lens, 8 is an auxiliary mirror, 9.25b is an optotype plate, 20a and 20b are light emitting elements, and 21 is a half mirror.
122a and 22b are fixation lights, 23 is a lighting switch, 24
26b is a driving circuit, 26b is a lamp, H is a housing, H' is a protrusion, and C is a film box. Patent applicant Canon Co., Ltd. Figure 3

Claims (1)

[Scope of Claims] 1. An observation/photography optical system for observing or photographing the fundus of the eye to be examined, and at least a part of the observation/photography optical system for observing the anterior segment of the eye in order to align the eye to be examined. An anterior eye segment observation optical system is housed in or attached to a housing, and a luminescent optotype is provided at a predetermined position on the outside of the housing, which can be lit while the anterior eye segment is being observed by the anterior eye segment observation optical system. Features fundus camera. 2. The fundus camera according to claim 1, wherein the luminous optotypes are provided one each on a protrusion of the left and right outer walls of the housing. 3. A control means is provided which enables switching between the observation and photographing optical system and the anterior eye segment observation optical system, and displays the luminous optotype only during the anterior eye segment observation in conjunction with this switching. The fundus camera according to scope 1. 4. Claim 1, comprising means for detecting the left and right sides of the subject's eye to be observed and photographed, and means for selectively lighting up a luminous optotype on the opposite side of the subject's eye detected by the means. The fundus camera described in . 5. means for presenting a second luminescent optotype located at a substantially conjugate position with the fundus of the subject's eye toward the subject's eye through the observation and photographing optical system, the second luminescent optotype and the first luminescent optotype; The fundus camera according to claim 1, further comprising a control means for displaying a light-emitting target in a switchable manner. 6. The fundus camera according to claim 1, wherein the luminescent target is presented to the eye on the opposite side of the eye to be examined via an optical system provided on the outer wall of the housing.