JPH024286B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an eye test target device used, for example, as a binocular visual acuity tester.

[Prior Art] Visual acuity testing devices have been widely used in the past, and tests are performed by presenting a translucent or non-transparent optotype inserted into the device to a subject. The most commonly performed visual acuity test involves one eye being occluded, and there are many devices that do not require complicated mechanisms, which is suitable for widespread use of visual acuity tests. however,
This test is performed with one eye shielded, so it is not suitable for precise measurements.

In order to perform precise measurements, a binocular visual acuity tester has traditionally been used. For example, as shown in Fig. 2, the optotype 1L for the left eye and the optotype 1R for the right eye are placed on different planes. In front of the displayed rotating optotype drum 2, an optical path separation shielding plate 3 for left and right eyes, an eyepiece for the left eye 4L, and an eyepiece for the right eye 4R are arranged, and furthermore, an illumination light source 5 is arranged diagonally in front of the rotating optotype drum 2. It is known that the system is installed with a

For example, during a right eye test, the right eye optotype 1R of the Landolt ring of the rotating optotype drum 2 is displayed on the right side,
A plane with nothing displayed on it is presented on the left side, and when the rotating optotype drum 2 is rotated during the left eye examination, the optotype for the left eye 1L is displayed on the left side, and a plane with nothing displayed on the right side. Presented.

In the case of this conventional example, since both eyes are open, one eye to be examined always presents a visual field with no optotype, which gives an unnatural feeling, making it impossible to perform the test under everyday visual conditions. There is a drawback. Furthermore, when presenting the optotype, a mechanical drive unit such as a motor for rotating the rotary optotype drum 2 is required, which also has the drawback of increasing the size of the apparatus.

[Object of the Invention] An object of the invention is to provide an optotype device for eye examination that allows easy and accurate eye examination in a state of natural vision with both eyes.

[Summary of the invention] The gist of the present invention for achieving the above object is as follows:
In a device that performs eye examination by presenting optotypes through eyepieces for the left and right eyes, there is an opaque reflective peripheral frame provided so that the visual fields of the left and right eyes substantially match, and a left and right eyepiece within the peripheral frame. A transmission type optotype provided separately for the eye and for the right eye, each operated independently, whose light transmittance is changed by an electric field and can be turned on or off; This optotype device for eye examination is characterized in that it includes an illumination means for illuminating the peripheral frame from the observation side.

[Embodiments of the Invention] The present invention will be explained in detail based on the embodiment shown in FIG.

FIG. 1 shows an embodiment in which the present invention is applied to an optotype device for visual acuity testing, in which an illumination light source 12 is installed diagonally behind a pair of transmissive liquid crystal optotypes 11L and 11R for the left and right eyes that display Landolt rings, etc. It is located. Each of these liquid crystal optotypes 11L, 11R is supported around the periphery by an opaque peripheral frame 13 having diffuse reflection characteristics, and behind the liquid crystal optotypes 11L, 11R there is a first reflecting mirror 14 as a light guiding means, and a first reflecting mirror 14 on the observation side. Similarly, second reflecting mirrors 15 are disposed obliquely above the light guiding means. LCD optotype 11L, 11R
A third reflecting mirror 16 that deflects the light flux toward the eye to be examined is arranged above, and an eyepiece for the left eye 17L and an eyepiece for the right eye 17R are respectively installed between the reflection mirror 16 and the eye to be examined. has been done. The first reflecting mirror 14 guides a part of the luminous flux from the illumination light source 12 to the liquid crystal optotypes 11L and 11R, and the second reflecting mirror 15 guides a part of the luminous flux from the illumination light source 12 to the peripheral frame part 13. arranged to guide you.

The light flux emitted from the illumination light source 12 is reflected by the first reflecting mirror 14 and directed upward, illuminating the liquid crystal optotypes 11L and 11R from behind, and causing the optotypes 11
The patterns such as individual Landolt rings presented one by one by L and 11R are deflected as transmitted light by the reflecting mirror 16, and are reflected by the left eye eyepiece 1.
7L and is observed by the eye to be examined through the right eyepiece 17R. Note that the reflective mirror 16 is arranged to deflect the optical path so that the subject's eye can easily observe the liquid crystal optotypes 11L and 11R. In a normal visual acuity test, one optotype 11 is not presented with anything, and patterns are sequentially presented on the optotype 11 on the side of the eye to be tested.
The same pattern may be presented to 1L and 11R at the same time, or different patterns may be presented at the same time.

On the other hand, a part of the luminous flux emitted from the illumination light source 12 is reflected by the second reflection mirror 15,
The peripheral frame portion 13 is irradiated, and the eyepiece lenses 17L, 17
It is observed by the eye to be examined as reflected light from the peripheral frame 13 through R, and the liquid crystal optotype 11L,
This makes it possible to observe 11R.

Therefore, the eye to be examined looks at the liquid crystal optotypes 11L and 11R for the left eye and the right eye, respectively, surrounded by the peripheral frame 13, through the left eye eyepiece 17L and the right eye eyepiece 17R. You can observe it naturally as if you were observing it with your own eyes.

Note that, if desired, the reflective mirrors 14 and 15 can be removed to increase the number of light sources to two or more; however, as in the embodiment, the reflective mirrors 14 and 15 are used to reduce the number of light sources to one. This results in a more compact device with better operability. Note that the same effect as that of a transmissive liquid crystal can be obtained even if a transmissive electrochromic material is used.

[Effects of the Invention] As explained above, the optotype device for eye examination according to the present invention uses a transmission type optotype, so a clear optotype image can be obtained, and furthermore, a peripheral frame portion is formed around the optotype. By providing this, the visual field of both eyes becomes almost the same. Furthermore, the size of the visual target can be kept to the minimum necessary size, and the field of view can be widened. Furthermore, since the visual fields are displayed one by one, there is little difference between the right visual field and the left visual field, giving a natural feeling to the subject and facilitating automation.

[Brief explanation of drawings]

FIG. 1 shows a configuration diagram of an embodiment of the optotype device for eye examination according to the present invention, and FIG. 2 is a perspective view of essential parts of a conventional example. Reference numeral 11 is a transmission type liquid crystal optotype, 12 is an illumination light source,
13 is a peripheral frame, 14, 15, and 16 are reflecting mirrors, and 17 is an eyepiece lens.

Claims (1)

[Scope of Claims] 1. An apparatus for performing an eye examination by presenting visual targets through eyepiece lenses for the left and right eyes, comprising: an opaque reflective peripheral frame provided so that the visual fields of the left and right eyes substantially coincide;
Transmissive optotypes are provided separately for the left eye and right eye in the peripheral frame, each of which operates independently and whose light transmittance can be changed by an electric field and can be turned on or off, and the optotypes. An optotype device for eye examination, comprising: an illumination means for illuminating the peripheral frame from behind and for illuminating the peripheral frame from the observation side. 2. The optotype device for eye examination according to claim 1, wherein the optotype presents patterns to be detected one by one. 3. The optotype device for eye examination according to claim 1, wherein the optotype is a transmissive liquid crystal. 4. The optotype device for eye examination according to claim 1, wherein the optotype is made of a transmission type electrochromic material. 5. The optotype device for eye examination according to claim 1, wherein the illumination means uses one light source to illuminate the optotype and the surrounding frame using a reflecting mirror. 6. The optotype device for eye examination according to claim 1, wherein the illumination means uses two light sources to respectively illuminate the optotype and the peripheral frame.