JPH02124135A - Eyesight testing device - Google Patents

Abstract

PURPOSE:To exactly display an eyesight value in correspondence to a distance by displaying the eyesight value to be calculated by an arithmetic means to calculate the eyesight value of a visual target which is provided in advance in correspondence to the distance to a person to be tested to be obtained by a distance measuring means to measure the distance from the visual target and the standing position of the person to be tested. CONSTITUTION:An eyesight testing device is composed of a distance measuring device 2, an arithmetic unit 3 and a display device 4. The distance measuring device 2 is provided to measure the distance from the visual target 1, which is illuminated by an illuminating device from a back surface, up to the standing position of the person to be tested, and the arithmetic unit 3 is provided to calculate the eyesight value to the visual target 1 based on the above mentioned distance to be obtained by the distance measuring device. The display device 4 is provided to display the eyesight value to be calculated by the arithmetic device.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is directed to calculating and displaying an accurate visual acuity value corresponding to the distance, regardless of the distance from the visual acuity chart to the subject. This invention relates to a visual acuity testing device that can perform visual acuity testing.

(Prior art) Conventionally, a subject is stood at a predetermined distance, such as a 3m visual target or a 5m visual target, and an eye chart having a visual target of a size corresponding to the distance is used. The test was performed by showing it to the subject.

In addition, in the case of a test subject who cannot see the largest optotype at the above-mentioned predetermined distance, bring the optotype closer to the testee until it is visible, and convert the visual acuity using the ratio of this shortened distance to the predetermined distance. I was looking for value. That is, at a predetermined distance of 5 m, 0.
If the visual target of 0.1 cannot be recognized, have the subject approach the visual acuity chart to a position where it can be recognized, and the longest distance that can hide the visual target of 0.1 is 0.1 × -, For example, 0.1 at 1m
If this can be recognized, the visual acuity value of this subject will be 0.02.

(Problems to be Solved by the Invention) Conventional visual acuity testing devices use a large number of optotypes, so it is difficult to accommodate the optotypes with particularly low visual acuity values due to limited space. , There was a problem that it became. For example, in the case of a 5m visual acuity chart, the visual acuity value is 0.
The size of the visual target 1 is 72 mm x 72 m, which is 0.05
The size of the visual target reaches approximately 145 x 145 mtn.

In addition, when measuring visual acuity value of 0.05 or less, 0.0
Using the optotype No. 5, bring the optotype close to the subject until the optotype can be seen, and apply 0.05 J at r 2.5 m.
Converted to a distance in m, it was displayed as 0.0254 (at 5 m). Therefore, in this case, it is necessary to measure the distance at which the optotype becomes visible with a tape measure, etc. It was a complicated task.

Furthermore, in a visual acuity test, the farther the distance from the eye chart to the test subject, the less accommodative power the eyes have, which means that accurate visual acuity values can be measured.

However, if a large space cannot be reserved for the visual acuity test device, a short distance visual acuity chart must be used, which is limited by the available space, and therefore accurate visual acuity measurements cannot be made.

The present invention has been made in view of the above-mentioned problems, and includes:
Even for subjects with visual acuity lower than 0.1 or 0.05, this method does not require the complicated work of measuring the distance at which the subject can see the visual acuity chart with a tape measure. The distance measuring means provided by the user measures L, and the visual acuity value is calculated based on the measured value (-1 The calculated result is displayed as the visual acuity value, so it is only necessary to accommodate visual targets up to about 0.1. An object of the present invention is to provide a visual acuity testing device that can be stored in a small size.

(Means for Solving the Problems) In order to achieve the above object, the visual acuity testing device of the present invention includes a distance measuring device that measures the distance from an optotype provided in the visual acuity testing device to a position where a subject stands. a calculation means for calculating the visual acuity value of the visual target; and display means for displaying the determined visual acuity value.

(Example) An example of the visual acuity testing device of the present invention will be described based on the drawings.

As shown in FIGS. 1 and 2, the visual acuity test device 10 includes:
An optotype 1, a distance measuring device 2 for measuring the distance from the optotype 1 to the position where the subject stands, and a visual acuity value of the subject with respect to the optotype 1 based on the distance obtained by the distance measuring device. It is composed of an arithmetic device 3 for calculating the visual acuity value, and a display device 4 for displaying the visual acuity value calculated by the arithmetic device.

It is assumed that the optotype 1 is illuminated by an illumination device from the back side, and a visual acuity chart is printed on the front panel. The size of the optotype shall be the same as that used for the 4m or 5m visual acuity chart.

As the distance measuring device 2, any known method can be selected as long as it can measure the distance from the subject to the visual acuity testing device.

The arithmetic unit 3 is built into the visual acuity testing device 10 and calculates the visual acuity value from the measured distance and the size of the optotype, and includes, for example, a 4-bit microprocessor.
is used.

The display device 4 is an element that digitally displays the visual acuity value calculated by the arithmetic device 3, and is an element that digitally displays the visual acuity value calculated by the calculation device 3.
, one numerical display element is attached. The display element may be, for example, an LCD or a 7-segment LED, and is assumed to display four digits. However, the portion displaying the high visual acuity value may be 3 digits.

FIG. 3 shows an example in which the visual acuity testing device of the present invention is implemented as a roll-type wall-mounted vision chart, and FIG. 4 shows an embodiment in which it is implemented as a replaceable wall-mounted vision chart. . In FIGS. 3 and 4, 1 represents an optotype, 2 represents a distance measuring device, and 4 represents a visual acuity display device.

In addition, in other embodiments and 1 to 1, it is also possible to use the optotype as a chart of a projection type chart projector. In this case, if the position where the examinee stands is the same as the position where the chart projector is installed, the visual acuity value will be constant regardless of the distance to the screen, but if the distance between the examinee and the chart projector is If there is a difference, the correct visual acuity value can be obtained by using the visual acuity testing device of this embodiment.

(Effects of the Invention) Since the present invention is configured as described above, even if the distance between the optotype provided in the visual acuity testing device and the subject is arbitrarily changed, the visual acuity remains unchanged according to the distance. Values can be displayed accurately, no troublesome work is required for distance measurement, and the capacity of the device can be kept small.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of the visual acuity testing device of the present invention, FIG. 2 is a front view of one embodiment, and FIGS. 3 and 4 are perspective views of another embodiment. ...Visual target...Distance measuring means...Calculating means...Display means...Visibility testing device Fig. 1 Fig. 2 Fig. 3 Figure 4

Claims (1)

[Scope of Claims] A visual acuity testing device for measuring the visual acuity of a subject, comprising: distance measuring means for measuring the distance from an optotype provided in the visual acuity testing device to a position where the subject stands; a calculation means for calculating the visual acuity value of the optotype set in advance according to the distance to the subject obtained by the distance measuring means; and for displaying the visual acuity value calculated by the calculation means. A visual acuity testing device characterized by having a display means.