JPS6346691B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ophthalmological instrument equipped with an eyelid position detection function that detects the presence of eyelids by measuring the light reflected from the iris that adjusts the size of the pupil of the eye being examined. be.

Fundus photography is frequently performed not only in ophthalmology, but also in internal medicine, neurology, and other medical treatments. Recently, with the spread of mass medical examinations, non-mydriatic fundus cameras that use infrared light have become popular, as they are easy to use and do not cause discomfort or the risk of seizures due to mydriatic drops.

The principle of imaging using this non-mydriatic fundus camera is that instead of forcibly dilating the pupils with mydriatic drops, we wait for the subject's pupils to naturally dilate in a dimly lit room.
This method uses infrared light, which is invisible to the human eye, to observe and focus, and then uses a photographic light source such as a strobe light to take a photograph.
For this reason, once the photographing light source is turned on, the iris of the eye to be examined undergoes miosis, and it takes time to photograph the eye again. On the other hand, if the eyelids blink during photography, the photography will fail, but if the photographer does not notice that the subject blinked, it may not be known until the film is developed. Furthermore, even if a person notices blinking, it takes a considerable amount of time to re-photograph the blink due to pupil miosis.

An object of the present invention is to solve the above-mentioned problems and detect the presence of an eyelid covering the eye to be examined using an eyelid detection light beam that is focused on the iris that adjusts the size of the pupil of the eye to be examined. The object of the present invention is to provide a device for illuminating the eye to be examined, especially an ophthalmological instrument equipped with an eyelid position detection function that can stop emitting light from a photographing light source during photography. an observation/photographing optical system having an objective lens, and a light projection for projecting an eyelid detection light beam having a wavelength range different from that of the observation light irradiation means of the observation/photographing optical system onto the iris portion around the pupil of the eye to be examined. a measuring means for guiding the reflected light of the eyelid detection light beam from the iris portion of the eye to be examined to a photoelectric conversion means and measuring the eyelid within a range necessary for an ophthalmological examination based on the output of the measuring means; The present invention is characterized by comprising a detection means for detecting whether or not.

The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 is a configuration diagram showing an example of the optical system of a fundus camera. Reference numeral 1 is an observation light source consisting of a tungsten lamp, etc., and the light emitted from this observation light source 1 is passed through a condenser lens 2, which transmits infrared light. The light enters a mirror 6 through a filter 3, a photographing light source 4 consisting of a xenon discharge tube, etc., and a condenser lens 5, where it is deflected and sequentially passes through a ring slit plate 7, relay lenses 8 and 9, and then enters a perforated mirror 10. I'm starting to reach it. The light incident on the perforated mirror 10 from the above-mentioned illumination optical system is transmitted to the perforated mirror 10.
The light is reflected in the direction of the eye E to be examined, illuminates the fundus Ef of the eye E, returns to the original optical path, and further passes through the perforated mirror 10 to reach the observation optical system.
An objective lens 11 is arranged between the perforated mirror 10 and the subject's eye E, and behind the perforated mirror 10, along the optical axis, there are a focusing lens 12, a photographing lens 13, a flip-up mirror 14, A shutter 15 and photographic film 16 are arranged in sequence. Also,
On the reflective side of the flip-up mirror 14, there are field lenses 17 placed sequentially along the optical axis at positions conjugate with the photographic film 16, and a mirror 1 for changing the optical path.
8, a relay lens 19, and an image pickup tube 20 are arranged.

In this fundus camera, the observation light source 1 and the photographing light source 4 are substantially conjugate with respect to the condenser lens 2, and the observation light source 1 is turned on during observation, and the photographing light source 4 is turned on instantaneously during photography. The light source image is once formed near the ring slit plate 7 by another condenser lens 5, and then by the relay lenses 8, 9.
As a result, an image of the annular opening of the ring slit plate 7 is formed in the vicinity of the perforated mirror 10, where the illumination light is reflected and travels to the left. Then, after forming an image of the annular aperture near the iris of the eye E to be examined using the objective lens 11, the fundus Ef is illuminated.

The reflected light from the fundus Ef travels to the right and passes through the objective lens 1.
1, the light passes through a perforated mirror 10 and is focused and imaged by a focusing lens 12 and a photographing lens 13. During observation, the fundus image is guided upward by the flip-up mirror 14 located at the solid line position, and is observed by a TV monitor (not shown) via the relay lens 19 and image pickup tube 20. During photography, the flip-up mirror 14 is positioned at the dotted line position. The fundus image is instantly opened by the shutter 15.
The image is formed on the photographic film 16 via the.

Reference numeral 21 denotes a light source for eyelid detection, and a projection lens 22 is disposed on its optical path toward the eye E to be examined, and the reflected light from the eye E is transmitted via an objective lens 11 to a light receiving element 23 consisting of, for example, a linear sensor. It is designed to be incident on . The projection light from the eyelid detection light source 21 is made to form an image on the iris of the eye E to be examined by the projection lens 22, and the arrangement of the light receiving element 23 that receives the reflected light is such that it is conjugate with the iris with respect to the objective lens 11. It is said to be the location. Furthermore, the lamp 24
The light is turned on when the photographing light source 4, which was prepared to emit light, stops emitting light.

As shown in FIG. 2, the wavelength range of the observation light source 1 is Z1, and the wavelength range Z2 of the eyelid detection light source 21 is distinguished from the wavelength range Z1 of the observation light source 1.

Figure 3 shows the eyelid detection spot image on the surface of the iris Ei and the position of the fundus illumination light for observation, and P1 is the ring-shaped spot inscribed in the dilated pupil of the eye E. The fundus illumination light P2 is a spot image produced by the eyelid detection light source 21. Figure 4 shows a state in which the eyelid El is lowered, and the eyelid detection spot image P2 shows the eyelid El.
Illuminating El.

FIG. 5 shows a reflected spot image P on the light receiving element 23.
2' and the light-receiving element 23. When the eyelid El is raised, the output of the light-receiving element 23 is the iris.
Since the amount of reflection from Ei is large, a clear level difference occurs depending on the presence or absence of the reflected spot image P2', and the output is in the state shown in A. When the eyelid El lowers and the reflected spot image P2' from the iris Ei disappears,
The reflected spot image P2' consists only of scattered light from the surface of the eyelid El, and the obtained reflected spot image P2' is no longer clearly formed, and as in output B, the level difference between the peak and valley is not clear. It becomes clear. Therefore, by measuring the level difference between the peak and valley of the outputs A and B, it is possible to determine the presence of the eyelid El.

The fundus illumination light P1 and the eyelid detection spot image P2 are separated by separating these positions as shown in FIGS. Z1 and the spot image P2 is set in the region Z2 having a longer wavelength than that, so this can be carried out without any problem.

In order to clearly distinguish the eyelid detection light flux from other external light, the eyelid detection light source 21 emits light in a pulsed manner and frequency modulates it, and a bandpass filter tuned to this is installed in the electric circuit of the light receiving section. May be inserted.

FIG. 6 shows a second embodiment, in which the eyelid detection light source 2
A mask 25 having a circular aperture is placed between the projection lens 22 and the projection lens 22, and the reflected spot image P2' from the iris Ei is transmitted to the light receiving element 23 via the light receiving lens 26.
is guided by.

Further, FIG. 7 shows a third embodiment, in which the mask 2
5 and the projection lens 22.
7 is inserted, and the reflected spot image P2' from the iris Ei is
is received by the projection lens 22, and the beam splitter 2
The light is guided to the light receiving element 23 via 7. .

In the above-mentioned embodiment, the electric circuit is configured such that when the eyelid position detection mechanism determines that the eyelid El exists in a range that is inconvenient for optometry, the photographing light source 4 does not emit light even if the photographing button of the fundus camera is pressed. This makes it possible to eliminate poor imaging due to eyelid El. Further, at the same time when the photographing light source 4 stops emitting light, the photographer can be informed that re-photographing is possible by turning on a buzzer or a lamp 24 built into the fundus camera.

As explained above, the ophthalmological instrument equipped with the eyelid position detection function according to the present invention can detect the eyelids by using an illumination light source for eyelid detection that forms an image on the iris in addition to the illumination light for observation and photography. The detection spot image can be irradiated at the most suitable position, making it possible to avoid photographing with drooping eyelids.

[Brief explanation of drawings]

The drawings show an embodiment of the ophthalmological instrument equipped with an eyelid position detection function according to the present invention, and FIG. 1 shows its optical layout, and FIG. 2 shows the wavelength ranges used by the fundus illumination light and the eyelid detection light source. Fig. 3 is a front view of the relative position of the fundus illumination light and the eyelid detection spot image on the iris of the subject's eye, and Fig. 4 shows the projection point of the spot image on the iris covered by the eyelid. Front view of condition, 5th
Figures 6 and 7 are explanatory diagrams of the state of the eyelid detection spot image on the light receiving element and the difference in output depending on the presence or absence of eyelids.
The figure is a layout diagram of another embodiment of the eyelid detection optical system. Reference numeral 1 is an observation light source, 3 is an infrared transmission filter, and 4 is an infrared transmission filter.
1 is a photographic light source, 7 is a ring slit plate, 11 is an objective lens, 14 is a flip-up mirror, 16 is a photographic film, 20 is an imaging tube, 21 is a light source for eyelid detection, 22
is a projection lens, 23 is a light receiving element, 25 is a mask,
26 is a light receiving lens, 27 is a beam splitter, E
is the eye to be examined, Ei is the iris, El is the eyelid, P2 is the eyelid detection spot image, and P2' is the reflection spot image.

Claims (1)

[Claims] 1. An observation/photography optical system having an objective lens for irradiating and observing/photographing the eye to be examined, and a wavelength range different from that of the observation light irradiation means of the observation/photography optical system on the iris portion around the pupil of the eye to be examined. A light projecting means for projecting a light beam for eyelid detection, a measuring means for guiding the reflected light from the iris part of the eye to be examined of the light beam for eyelid detection to a photoelectric conversion means, and an output of the measuring means,
An ophthalmological instrument equipped with an eyelid position detection function, characterized in that it is equipped with a detection means for detecting whether or not the eyelids are present within a range necessary for an ophthalmological examination.