JPH07124118A - Simultaneous stereoscopic fundus camera - Google Patents

Abstract

PURPOSE:To obtain uniform right and left images without requiring skill by providing an index projecting optical system which projects an index to measure the balance of light quantity of right and left images on an eye to be examined, an index detection optical system, and a judging means which judges the light quantity balance. CONSTITUTION:Light is made incident on the eye to be examined via light sources 30a, 30b with wavelength different from that of illumination light for observation, a two-hole diaphram index plate 32 which separates a luminous flux to two luminous fluxes, an auxiliary lens 33, and a dichroic mirror 34 which transmits illumination light for photography/observation and reflects index projection light, and an index is imaged-formed on a pupil and the eyeground. An index image of the eyeground is introduced to a photodetector by transmitting a dichroic mirror 24 by an index optical system including the dichroic mirror 24. An index luminous flux is vignetted when a photographic optical axis is not located in the center of the pupil, which produces the unbalance of light quantity. Then, incident light quantity to the photodetector is compared by a mechanism to compare the light quantity, and a result is displayed by putting on a display mark provided in the neigh-borhood of a monitor and representing an aligning direction, and the position relation of the center of the pupil of the eye to be examined with a photographic device main body can be aligned correctly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simultaneous stereoscopic fundus camera for stereoscopically photographing the fundus of an eye to be inspected, and more specifically to an apparatus capable of obtaining a uniform left and right image.

[0002]

2. Description of the Related Art A conventional simultaneous stereoscopic fundus camera has a direct viewfinder as an observation optical system. As a direct view finder, two left and right fundus images are viewed with separate monocular eyepieces, two left and right fundus images are viewed side by side within the field of view of one monocular eyepiece, and left and right It has been proposed that two eye fundus images can be captured by a binocular eyepiece to enable even stereoscopic vision. The examiner performed a positioning operation while observing the fundus with these direct viewfinders to judge the quality of the observed image.

[0003]

By the way, in stereoscopic imaging of the fundus, uniformity of left and right images is important for diagnosis and analysis. In the conventional apparatus, the photographer had no choice but to determine the uniformity of the left and right images, particularly the uniformity of the brightness of the left and right images by directly looking at the balance of the brightness. However, such a judgment is delicate and requires a great deal of skill. In particular, when a non-mydriatic stereoscopic fundus camera photographs an elderly person whose natural mydriasis is insufficient, only one of the left and right light beams may be eclipsed by the pupil. It is an object of the present invention to provide an apparatus capable of obtaining a uniform left and right image without requiring any skill in a simultaneous stereoscopic fundus camera that simultaneously extracts two right and left light fluxes of the stereoscopic fundus camera from a pupil of an eye to be examined.

[0004]

In order to achieve the above object, an optometry apparatus of the present invention is characterized by having the following configuration. (1) In a simultaneous stereoscopic fundus camera that splits the reflected light flux from the fundus of the eye to be examined into two left and right light fluxes and shoots a pair of fundus images by the split two light fluxes, the light amount balance between the left and right images is measured on the eye to be examined. Index projection optical system for projecting an index for doing so, an index detection optical system for detecting an index image by the index projection optical system, and a determination means for determining the light amount balance based on the detection result by the index detection optical system. And a notifying means for notifying the determination result.

(2) The index projection optical system of (1) is characterized by having an index that is substantially conjugate with the fundus of the eye to be inspected and a two-hole diaphragm that is substantially conjugate with the pupil of the eye to be inspected.

(3) The index of (2) is such that the light beams divided by the two-hole diaphragm form images at different positions on the fundus.
It is characterized in that there are two indexes corresponding to two light fluxes.

(4) In the two-hole diaphragm of (2), the image on the pupil of the eye of the two-hole diaphragm has an interval substantially the same as the interval of the two-hole diaphragm for photographing, and the diameter is not less than the diaphragm diameter. It is characterized by having.

(5) In the simultaneous stereoscopic fundus camera of (3), the index light receiving optical system has a light receiving element at a position substantially conjugate with the fundus, and the light receiving elements measure the brightness of the two index images, respectively. It is characterized by

(6) The index light source of the index projection optical system of (1) has a wavelength different from that of the observation light source.

(7) The notifying means in (1) is characterized in that it has display means for displaying the left and right correction directions of the photographing optical axis.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. [Structure] FIG. 1 is a schematic layout view of an optical system when an embodiment of the present invention is viewed from the side, and includes an illumination optical system, a photographing optical system, and an observation optical system. 2 is a sectional view taken along the line AA of the photographic optical system of FIG. 1 as seen from above, and FIG. 3 is a sectional view taken along the line BB of the portion of the observation optical system shown in FIG. 1 as seen from the left side. (Illumination optical system) 1 is a halogen lamp that is an illumination light source for observation, 2 is a condenser lens for a halogen lamp, and 3 is used when so-called non-mydriasis imaging is performed using natural mydriasis in a dark place of the subject. An infrared filter that makes the observing illumination light as invisible light 4 is a flash lamp that is a photographing illumination light source, and 2'is a flash lamp condenser lens.

Reference numeral 5 is a beam splitter, 6 is a condenser lens, and 7 is a ring slit which is a ring-shaped aperture stop. The shape of the ring slit 7 is shown in FIG. 8
Is a mirror for changing the direction of the optical path, and 9 is an illumination system relay.
Reference numeral 10 denotes a lens having a small black spot in the center thereof for removing harmful light, 34 denotes a dichroic mirror that reflects the index light flux and transmits illumination light, 11 denotes an illumination system relay lens, 12 Is a perforated mirror having an opening for photographing light flux at the center. The halogen lamp for observation and the flash lamp for photographing are arranged at conjugate positions by the condenser lenses 2 and 2 ', and both light fluxes are coaxially combined via the beam splitter 5 to illuminate the ring slit 7. The light flux of the ring slit 7 passes through the dichroic mirror 34, forms an intermediate image near the opening of the perforated mirror 12 by the relay lenses 9 and 11, and is reflected by the donut-shaped mirror surface. , 13 is coaxial with the optical axis of the objective lens,
An image of the ring slit 7 is formed in the vicinity of the pupil of the eye 14 to be inspected, diffused in the eye 14 to be inspected, and the fundus of the eye is illuminated.

(Photographing optical system) 13 is an objective lens which is also used as an illumination optical system, and 15 is a two-hole diaphragm which divides a light beam into left and right for stereoscopic observation and photographing. The two-hole aperture 15 is shown in FIG. Reference numerals 16 and 17 denote light beam separating prisms, and 16 has a function of switching the left and right of the divided light beam so as to prevent the stereo image from becoming an inverse stereoscopic body, and 17 has a function of keeping the subsequent light beams in parallel at a predetermined interval. Fulfill 1
Reference numeral 8 is a relay lens, and 19 is a focusing lens which can be moved in the optical axis direction and can be adjusted according to the refractive power of the eye to be inspected. Numeral 22 is a return mirror for the observation optical system, which retreats to the position indicated by the broken line during photographing. An image forming lens 20 forms an image of the fundus on the film surface of 21. The reflected light from the fundus of the eye 14 to be examined forms an inverted intermediate image at the point C by the eye lens to be inspected and the objective lens 13 and then passes through the aperture of the perforated mirror 12 to separate the light flux by the two-hole diaphragm 15. However, since the two-hole diaphragm is arranged so as to be conjugate with the pupil of the eye to be inspected through the objective lens 13, the light flux divided into right and left for stereo on the pupil is matched at point C and separated again. It will be. That is, the size of the light flux for photographing is practically determined on the pupil plane. Further, as described above, the image of the ring slit 7 of the illumination optical system is formed in the vicinity of the pupil of the subject's eye 14. Since the ring slit 7 and the two-hole diaphragm 15 are at substantially conjugate positions on the pupil in this way, when the ring slit and the two-hole diaphragm are superposed on the pupil plane, the result is as shown in FIG. Reference numeral 41 is the aperture of the two-hole diaphragm 15, and 42 is the slit image of the ring slit 7.

The luminous flux of the fundus illuminating by the ring slit 7 is
The illumination light flux is introduced by utilizing a portion on the pupil plane that does not interfere with the photographing light flux, that is, a portion mainly above and below the vertical dimension of the two light fluxes. In this embodiment, as shown in FIG. 7A, the shape of the ring slit 7 is designed so that the larger the diameter of the mydriasis, the more the light quantity enters the fundus. Even when the pupil diameter of the eye to be inspected is not sufficient and the two light fluxes 41 for photographing are full left and right as shown in FIG. 7-b, the light can be introduced from the upper and lower portions shown by 43. In the above-mentioned photographing optical system, the reflected light from the fundus of the eye 14 to be examined forms an inverted intermediate image at the point C by the objective lens 13 and then passes through the aperture of the perforated mirror 12 and is formed by the two-hole diaphragm 15. The light flux is separated. The light flux that has passed through the two-hole diaphragm and has been made parallel by the light flux separation prisms 16 and 17a, 17b is released by the relay lenses 18a, 18b, and the forward lens.
The imaging lens 2 passes through the cassing lenses 19a and 19b.
Left and right images are formed on the film surface 21 at 0a and 20b. For the fundus illumination of the eye to be inspected, the light flux from the halogen lamp 1 is used as the invisible light to the eye to be inspected by the infrared filter 3 at the time of non-mydriatic observation, but the flash lamp 3 is synchronized with the exit of the return mirror 22 at the time of photographing. Since it is used after being used, a sufficient amount of light can be obtained for instant shooting.

(Observation Optical System) The observation optical system includes the objective lens 13 of the photographing optical system to the focusing lenses 19a and 19a.
The optical system up to b is shared. Reference numerals 23a and 23b are relay lenses, 24a is a dichroic mirror for directing a light beam inward for the purpose of narrowing the optical axis and selectively transmitting an index light beam, and 24b is a mirror for directing the light beam inward. -, 25 are mirror members for directing a light beam upward, 2
Reference numeral 6 is a thin deflection angle prism for aligning the left and right positions of two images. 27 is an imaging lens of the observation optical system, 28
Is an image pickup element for a TV camera such as CCD, and 29 is a light receiving element for measuring the index light from 24a. Objective lens 1
3 through the focusing lens 19a, 19b, the reflected light from the fundus is reflected upward by the return mirrors 22a, 22b at the positions shown by the solid line except when photographing, Relay lenses 23a, 23b, dichroic mirror 24a, mirror 24b, mirror member 2
5, guided by the deflection prism 26 and the imaging lens 27, and forms an image on the image pickup device 28 which is conjugate with the film surface 21. TV
An example of the TV monitor screen display of the image captured by the camera is shown in FIG. 8, which is a pair of left and right image displays used for stereoscopic photography. In this embodiment, one TV camera and one T
Although an example of the V monitor is shown, the T and T images can be transmitted through the image synthesizing circuit using dedicated TV cameras.
There is no problem in changing only the V monitor or using multiple TV monitors depending on the convenience.

(Index projection system) Two light sources 30a and 30b having a different wavelength from the observation illumination light, a two-hole diaphragm 31 (see FIG. 10) for separating the index projection light beam into two light beams, and an index plate 32 (FIG. 9). ), An auxiliary lens 33 for index projection, a dichroic mirror 34 that transmits the illumination light for shooting and observation and reflects the index projection light. The index projection light reflected at 34 is coaxial with the illumination optical system. It is incident on the optometry 14. The operation of the index projection optical system will be described with reference to FIG. FIG. 11 shows an index projection system (a dichroic mirror-34 and a perforated mirror-1) including an optical system shared with an illumination optical system.
2 is omitted) is a view of the configuration viewed from above. Here, the two-hole diaphragm 31 and the pupil position of the eye to be inspected, and the index plate 32 and the fundus of the eye to be inspected are arranged so as to have a substantially conjugate relationship.
The light flux emitted from the index light source 30a transmits only the diaphragm 31a in FIG. 10 and illuminates the index 32a in FIG. The luminous flux emitted from the index light source 30b is similarly drawn by the diaphragm 3
Only 1b is transmitted and the index 32b is illuminated. The images (31'a, 31'b) of the two-hole diaphragm 31 on the pupil of the eye to be inspected are, as shown in FIG. 12, images of the index 32 (32'a, 32 ') on the fundus.
b) is as shown in FIG.

Here, the center-to-center distance of 31'a and 31'b and the size of each aperture image in FIG. 12 are equal to the center-to-center distance of the two-hole aperture 15 for photographing, and the aperture diameter is the same or the same. Make it larger than the above. As a result, when the photographing optical axis is not at the center of the pupil, the index light beam is eclipsed by the pupil, and the image formed by the eclipsed light beam of the index images 32'a and 32'b on the fundus is formed. Darker,
The light amount balance of 32'a and 32'b is lost. This is shown in FIG. 14 as a diagram. (Index light receiving system) The index light receiving system includes up to the dichroic mirror 24a of the observation optical system.
After passing through a, the light is guided to the light receiving element 29. Light receiving element 2
Reference numeral 9'is an index image 32 'formed on the fundus of the eye conjugate with the film surface.
Images a and 32'b are formed, and 32 "a and 32" b are formed on the light receiving element. Here, a mechanism for comparing the light amounts of the index images 32 ″ a and 32 ″ b formed on the light receiving element is provided. For example, the light receiving element is divided into two, and the index image 3
2 ″ a is imaged on the light receiving portion 29a and 32 ″ b is imaged on the light receiving portion 29b (FIG. 15). A predetermined amount of light is incident on the light receiving portion.

Here, assuming that the light quantities at 29a and 29b are X and Y respectively, the following results are obtained by comparing these X and Y. Light intensity on the light receiving part | Index brightness on the fundus | Vignetting on the pupil | Alignment direction X> Y | 32'a>32'b | 31'b | Shifting device to the left X = Y | 32'a = 32'b │ None │ Alignment completed X <Y │ 32'a <32'b │ 31'a | Shift the device to the right | By this, the positional relationship between the center of the pupil of the eye to be inspected and the imaging device main body Can be properly aligned. Based on the comparison result of the light amount of the light receiving unit, the examiner can know the moving direction of the alignment by turning on one of the display marks (44 in FIG. 8) provided near the monitor and indicating the alignment direction. it can.

[Operation] The operation of the optical system apparatus having the above configuration will be described. The optical system main body is housed in a casing and is mounted on an operation table that moves on a fixed table via a sliding mechanism. The photographer fixes the subject on the chin rest fixed to the fixing base. The halogen lamp 1, which is an illumination light source for observation, is turned on to illuminate the subject's eye 14. The photographer operates the operation console while looking at the observation image appearing on the TV monitor (see FIG. 8) to move the optical system main body forward, backward, leftward, rightward, and downward with respect to the eye to perform alignment so that a predetermined positional relationship is established. . When the alignment is substantially completed, the left and right fundus is observed on the TV monitor screen as shown in FIG. Then,
The photographer finely adjusts the alignment to finely determine the visual field, and moves and adjusts the focusing lenses 19a and 19b (not shown) to the positions where the focus can be changed to the best focus. (It may be configured according to the focus index etc.) Finally, the fine adjustment alignment of the left-right balance is completed according to the display as shown in 44 of FIG.

Alignment and focusing are completed,
When a shooting button (not shown) is pressed, the return mirror 22 retreats to the position indicated by the broken line, and the xenon flash lamp 4 emits light interlockingly, and the necessary amount of light for the film surface 21 is given to the fundus for shooting. The image captured on the film has an equal amount of left and right light, and an image effective for stable stereoscopic reproduction later can be obtained. For the above-described operation of the apparatus, a control system including a microcomputer inside the apparatus is used except for manual operation. As pointed out in the embodiments, the present embodiment can be modified in various ways, and these modifications are also included in the present invention within the scope of making the technical idea the same as the embodiment.

[0021]

According to the present invention, by detecting the outline balance of the index image, it is possible to obtain a stereoscopic fundus image with uniform brightness of the left and right images together with accurate alignment.

[Brief description of drawings]

FIG. 1 is a schematic layout diagram of an optical system when an example is viewed from the side.

FIG. 2 is a cross-sectional view taken along the line AA of the photographing optical system of FIG. 1 as seen from above.

3 is a BB view of the observation optical system portion of FIG. 1 as seen from the left side.
FIG.

FIG. 4 is a diagram showing a shape of a ring slit 7.

FIG. 5 is a diagram showing the shape of a two-hole diaphragm 15.

FIG. 6 shows a ring slit 7 and a two-hole diaphragm 15 on the pupil plane.
It is a figure which shows the state which overlapped.

FIG. 7-a is a diagram showing a portion for introducing a fundus illumination light flux.

FIG. 7-b is a diagram showing a portion for introducing a fundus illumination light flux.

FIG. 8 is a display mark showing a TV monitor screen and an alignment direction of an image obtained by capturing a fundus with a TV camera.

FIG. 9 is a diagram showing an index plate 32.

FIG. 10 is a diagram showing a two-hole diaphragm 31.

FIG. 11 is a view of the configuration of the index projection system (the dichroic mirror-34 and the perforated mirror-12 are omitted) viewed from above.

FIG. 12 is a diagram showing an image of a two-hole diaphragm 31 on a pupil of an eye to be inspected.

FIG. 13 is a diagram showing an image of an index 32 on the fundus.

FIG. 14 is a diagram showing a relationship between a photographic diaphragm image and an index light beam on the pupil and a balance of the index image light amount on the fundus.

FIG. 15 is a diagram showing a light receiving element 29 that forms an index image formed on a fundus.

[Explanation of symbols]

 7 Ring slit 15 Two-hole diaphragm 26 Declination prism 29 Light receiving element 30a, 30b Light source 31 Two-hole diaphragm 32 Index 34 Dichroic mirror

Claims (7)

[Claims] 1. The reflected light flux from the fundus of the eye to be examined is divided into two left and right
An index projection optical system for projecting an index for measuring a light amount balance of left and right images onto an eye to be inspected, in a simultaneous stereoscopic fundus camera which divides into two light beams and takes a pair of fundus images by the divided two light beams, and the index. It has an index detection optical system for detecting an index image by the projection optical system, a determination means for determining the light amount balance based on the detection result by the index detection optical system, and an informing means for informing the determination result. Characteristic simultaneous stereoscopic fundus camera. 2. The simultaneous stereoscopic fundus camera, wherein the index projection optical system according to claim 1 has an index that is substantially conjugated with a fundus of the eye to be inspected and a two-hole diaphragm that is substantially conjugated with a pupil of the eye to be inspected. 3. The index according to claim 2 is characterized in that there are two indexes corresponding to the two light fluxes so that the light fluxes divided by the two-hole diaphragm are imaged at different positions on the fundus. 3D fundus camera. 4. The two-hole diaphragm according to claim 2, wherein an image of the two-hole diaphragm on the eye to be inspected has an interval substantially the same as the interval of the two-hole diaphragm for photographing and has a diameter equal to or larger than the diaphragm diameter. A simultaneous stereoscopic fundus camera characterized by having. 5. The simultaneous stereoscopic fundus camera according to claim 3, wherein the index light receiving optical system has a light receiving element at a position substantially conjugate with the fundus, and the light receiving elements measure the brightness of each of the two index images. Simultaneous stereoscopic fundus camera featuring. 6. The simultaneous stereoscopic fundus camera, wherein the index light source of the index projection optical system according to claim 1 has a wavelength different from the wavelength of the observation light source. 7. The simultaneous stereoscopic fundus camera, wherein the notifying means according to claim 1 has a display means for displaying the left and right correction directions of the photographing optical axis.