JP2002000565A - Optotype - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the Landolt ring optotype which eliminates the situation that the results of a visual acuity test are not always accurate because answers are different by the character, intelligence, thought, age or the like of an individual patient and with which a test can be rapidly performed by fastening the answers of a patient. SOLUTION: The Landolt ring optotypes in which an optotype 4 having breaks 3 in a part of an annulus ring is arranged in longitudinal and horizontal rows with rearranging the breaks 3, wherein one optotype 5 among the Landolt ring optotypes 4 belonging to the row of the same visual acuity level is formed as a closed annulus ring having no break 3. The same principle may also be applied to the Snellen's test types having optotypes 4A in an E lettep form.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Landolt's ring or Snellen index visual acuity chart for measuring visual acuity.

[0002]

2. Description of the Related Art The measurement of visual acuity is based on the agreement of the 11th International Society of Ophthalmology (1909).
It has been negotiated to use a visual acuity chart using the ndolt ring. The Landolt's ring is an optotype consisting of an annulus partially formed with a cut, and such an annular optotype arranged in columns and rows by changing the direction of the cut is the Landolt's ring visual acuity chart. It is. In the Landolt's ring visual acuity table, the Landolt's ring is usually arranged in five parallel columns, and five Landolt's rings belonging to the same row correspond to the same visual acuity.

In order to perform a visual acuity test using the Landolt's ring visual acuity chart, the examiner instructs the patient at each level from low to high levels of visual acuity at each level, in which direction the Landolt's ring mark is directed. When the correct answer is made for three-fifths or more of the direction of the cut line of the five columns, it is determined that the eyesight of that level is present.

[0004]

Incidentally, the exchange of questions and answers between an examiner and a patient during an eyesight test is often subjective. That is, the patient, for example, "I don't know",
"Blurred,""Ican'tsee,""It's up or right next to it,"
In many cases, an answer such as "may be below" is given, but such an answer largely depends on the personality, intellect, thinking, age, desire, shame, etc. of the individual patient. In addition, each answer obtained from the patient may affect the subjective judgment of the examiner. Therefore, a situation may occur in which the result of the test using the Landolt ring chart is not always accurate depending on the patient. In addition, there is a problem that it often takes time for the patient to answer.

[0005] Therefore, an object of the present invention is to provide a test that is not inaccurate due to different answer results depending on the personality, intellect, thinking, desire, shame, age, etc. of the individual patient, and that the test is performed quickly. Obtaining an eye chart that enables

[0006]

According to the present invention, the above object is achieved by a visual acuity chart in which optotypes having a cut in a part of the periphery are arranged in columns and rows by changing the direction of the cut. This is achieved by forming at least one of the optotypes belonging to the column of the same visual acuity level as a closed optotype having no break around.

Further, according to the present invention, there is provided a visual acuity table in which optotypes having a break in a part of the periphery are arranged in columns and rows with the direction of the break changed.
This is achieved by forming at least one optotype for each row as a closed indicator around the row for all rows containing optotype optotypes.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. Before that, the Landolt's ring visual acuity table will be described with reference to FIG. The Landolt visual acuity table 2 shows a large number of Landolt's ring optotypes 4 each of which is formed with a ring 3 partially formed with a cut 3. , Top, diagonally upper right,
They are arranged in columns and rows instead of below, right, and so on. Landolt Ring Chart 4
Are arranged in five parallel columns, and five optotypes belonging to the same row correspond to the same visual acuity level. In the eyesight level, the top row of the table corresponds to an eyesight of 0.1, and the eyesight level becomes 0.1 as the row sequentially moves to the lower row.
5, 0.2, 0.3, 0.4,..., 2.0. In addition, at the top 0.1, only three optotypes 4 are shown.

In order to perform a visual acuity test using the Landolt's ring visual acuity table 2, the examiner gives a patient a break in the Landolt's ring eye chart at each level from the lowest level of visual acuity, 0.1, to a higher level. Inquiry as to which direction 3 is facing, and change the direction of the cut 3 of the optotype 4 in the same 5 rows to 3/5
When the answer is correct, it is determined that the eyesight has the level.

In such a Landolt's ring visual acuity table, in the present invention, as shown in FIG. 2, one of the five Landolt's ring optotypes belonging to the same visual acuity level row has a ring shape of one of the targets 4. The cut 3 is eliminated to form a closed ring 5. The number of optotypes to be a closed ring may be one for each row, but this does not prevent the number of optotypes from exceeding one.

[0011] When performing a visual acuity test using the Landolt's ring visual acuity table configured as described above, the examiner asks the patient for the unbroken visual target 5 among the visual targets 4 belonging to the row of each visual acuity level. Just ask which one (ie, which ring from left or right is closed).
If the target that belongs to the row having the same visual acuity level can correctly point out the blockage of the ring, it is determined that the breaks of the other four targets can be identified, and that is the correct answer. This prevents the patient from responding more subjectively to his or her visual appearance, making accurate eyesight decisions,
In addition, the inspection time is reduced.

Although the eye chart described above is the Landolt ring chart, the principle of the present invention is applied to the Snellen chart mainly used in the United States instead of the Landolt ring chart. can do. As shown in FIG. 3, the optotype 4A of the Snellen visual acuity table 2A is not a ring, but basically has the shape of a Roman letter E, and the side of the E-shaped optotype 4A where the cut 3A is (opened). Are directed up, down, left and right. As shown in FIG. 4, in another embodiment of the present invention, an E-shape belonging to a row having the same visual acuity level (however, in principle, it is also possible to arrange optotypes having the same visual acuity level in columns). At least one of the optotypes 4A is closed (opened) side with the gap 3A to make the optotype 5A with no gap around.
It is clear that the same effect as described for the Landolt's ring visual acuity table can be obtained by such a configuration.

Although the figures merely show tables as embodiments of the present invention, the tables may be printed on paper or the like or displayed on display devices.

[0014]

As described above, according to the present invention, among the optotypes belonging to the same visual acuity level column, at least one optotype is formed as a closed index with no gaps around it. By means, the patient's personality, intelligence,
This eliminates inaccuracies in the test results based on the patient's subjective responses that are influenced by thoughts, desires, shame, age, and the like, and enables a visual acuity test to be performed earlier than before.

[Brief description of the drawings]

FIG. 1 is a diagram showing a Landolt ring visual acuity table.

FIG. 2 is a diagram showing an embodiment of the present invention in the case of Landolt's ring visual acuity chart.

FIG. 3 is a diagram showing a part of a Snellen visual acuity table using a target having a shape of E;

FIG. 4 is a diagram showing another embodiment of the present invention in the case of a Snellen chart.

[Explanation of symbols]

 2 Landolt's ring visual acuity chart 2A Snellen visual acuity chart 3 Break 3A Break 4 Visual target 4A Visual target 5 Visual target with closed annular cut 5A Visual target with closed E-shaped cut

Claims (2)

[Claims] In a visual acuity table in which optotypes having a break in a part of the periphery are arranged in columns and rows by changing the direction of the cut, at least one of optotypes belonging to the same visual acuity column is arranged. A visual acuity chart characterized in that one of the targets is formed as a closed target that is not continuous around. 2. In a visual acuity table in which optotypes having a cut in a part of the periphery are arranged in columns and rows with the direction of the cut being changed, for all rows including optotypes with the same visual acuity level, A visual acuity chart characterized in that at least one optotype for each row is formed as a closed optotype with no gaps around it.