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Distance Vision Test

This test, also known as the Visual Acuity Test, tests the sharpness of vision by grading the ability of the eye to discern diminishing sizes of alphabets, numbers or shapes at a specified distance of 6 metres.

More Information on the Distance Vision Test

Visual acuity results are designated by fractions e.g. 6/60, 6/30, 6/24, 6/18, 6/12, 6/9, 6/6, 6/5. What do these fractions mean?

When we say that an eye has 6/24 visual acuity, we mean to say that the smallest row of letters the tested eye can discern at a distance of 6 metres is what a normal eye can discern at a greater distance of 24 metres. From this, we can see that the numerator 6 is a constant. The denominator varies and a number greater than 6 would represent less than normal visual acuity. The larger the denominator number, the poorer is the vision.

6/6 visual acuity is normal vision. 6/5 represents the fortunate 10 percent of the population that has better than normal vision.

The legal visual requirement to obtain a driving license is 6/12 in most countries. A person seeing worse than 6/60 despite best spectacle correction is considered to be legally blind. About 10 percent of people are fortunate to have better than 6/6 vision, that is 6/5.

The test is ideally done at 6 metres because light rays from objects seen at 6 metres and beyond reaches the eye as parallel rays and in the NORMAL EYE are focused precisely onto the central macula region of the retina without the need for any focusing effort.

In some countries, normal visual acuity is designated as 20/20 which simply is the same measurement designated in feet. In other countries, the fraction is converted to a decimal figure but they mean the same thing.