How to read the eye chart? Test your eyesight in 1 minute!

Some numbers on the eye chart are 1.0 and some are 5.0. How do you read them?

Which line should I see on the eye chart?

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Let’s learn about the vision chart today

Test your eyesight yourself without asking for help!

1. The role of the eye chart

An eye chart is a chart used to measure visual acuity, based on the principle of visual angle.

The vision charts used in China include: international standard vision chart, Landolt circular vision chart, logarithmic vision chart. Based on the function, there are near vision chart and far vision chart.

The visual acuity chart currently used mainly checks central vision, which can quickly provide a preliminary understanding of the visual function and is of great significance for the clinical diagnosis and treatment of eye diseases.

If your vision is declining, you can know it immediately. Therefore, this test is of great significance for the prevention, monitoring and treatment of eye diseases.

2. How to read the eye chart

There are many ways to record vision, two of the most common ones are:

① Five-point recording method (values ​​between 4.0-5.3), 5.0 is the normal standard vision line.

② Decimal recording method (values ​​between 0.1-2.0), 1.0 is the normal standard vision line.

The symbol on an eye chart that looks like an "E" is called an optotype.

The distance vision chart has a total of 14 rows of sight marks, which decrease in size and increase in number at irregular intervals.

The direction of the sight marks in the eye chart is uncertain. During the test, the subject needs to point out the direction of the opening of the sight marks. When he can see a row of sight marks clearly, the parameters on the left and right sides are the subject's vision values.

3. The relationship between visual acuity and refraction

Visual acuity, also known as naked eye visual acuity, refers to the ability of the retina at the fundus to form a clear image.

Diopter usually refers to the focal distance of a lens. Diopter: The image of an external object can form a focus after being refracted by the eye's refractive system, which is related to the position of the focus and the retina.

If the focus falls in front of or behind the retina or no focus is formed, it can be called refractive error. Refractive error is like a person's height and weight, which is an objective physical indicator.

Naked eye vision is checked with a vision chart, while diopter is measured with an optometry instrument. There is no one-to-one relationship or correspondence between the two.

It should be noted that naked eye vision cannot be used to infer refractive power, nor can refractive power be used to infer naked eye vision.

4. Methods of measuring visual acuity

Choose a vision chart that complies with the national standard "Standard Logarithmic Vision Chart" (GB11533-2011).

The eye chart should be placed 5 meters away from the eye being tested. If there is not enough space, the test and reading can be performed at a distance of 3 meters on the eye chart.

Eye chart (paper), lighting should be uniform, constant, non-reflective, non-glare, and there should be no strong direct light around. The eye being tested should be at the same level as the 5.0 line sight mark on the eye chart. Do not rub your eyes before the test, and do not stretch your head, squint, squint, or peek during the test.

Check the right eye first and then the left eye. Be careful not to press on the eyeball. You can cover the other eye with your palm or a small board. Judge the vision by observing the direction of letters of different sizes on the eye chart.