How well your eye lens and cornea can focus light on the retina. ![]() There are certain neurological and physical factors that determine your visual acuity. For instance, this test cannot predict how well you may see coloured and moving objects and objects that have similar brightness levels as their background.ĩ. This doesn’t determine the quality of your vision under various circumstances. Visual acuity test helps in determining your eye clarity under standard conditions. In such case, the letters on the chart are written in black and the background is white.Ĩ. The doctor also tests your visual acuity under high contrast conditions. It’s because you are either sitting or standing during the test and the objects (the letters and the chart in this case) that you are viewing are also static.ħ. Visual acuity is an invariable measurement. This is measured by your ability to read the letter in the Snellen Chart from a particular viewing distance as prescribed.Ħ. Visual acuity refers to the sharpness of your vision. Before we proceed further, let’s understand the difference:ĥ. There is a difference between visual acuity, vision, eyesight. For instance, if you are out on the road on a sunny day, you may enjoy a clear vision but your friend who doesn’t have a 20/20 vision and has low visual clarity compared to you, may too enjoy a clear vision under the same circumstance just because he or she is wearing a UV protected polarised glasses that has anti-reflective coating for that improved the contrast and also blocks glare. There is nothing called a “perfect vision.” Vision might defer depending on the circumstances. It was Donders who first started to diagnose vision-related issues in people by making them look at a chart and ask what they can see.Ĥ. Hermann Snellen was the colleague of Dr Fransiscus Donders. The Snellen Chart was developed by Dr Hermann Snellen, a Dutch Doctor, in the 1860s. ![]() In this case, the test can also be done from a distance that’s less than 20 feet. In some cases, the doctor may make you read the chart using a mirror. The doctor will perform the test in both of your eyes. You may have to cover one eye and then read the smallest line of letters that are visible to you. The doctor will make you stand at a distance of 20 feet from the chart and read all the letters without contact lenses or glasses. In the lines following the first line, the number-letter keeps increasing and the size of the letter keeps decreasing. The topmost line of the chart contains a single but very large letter. The chart contains a total of 11 rows of capital letters. Generally, doctors use the Snellen chart for measuring your visual acuity. A special eye chart is used for measuring your visual acuity or the clarity of your vision.ģ. Usually, vision correction glasses and processes aim at giving you a 20/20 vision. A 20/15 vision means that you can read the eye chart standing at 20 feet while any other person needs to stand at a distance of 15 feet to easily see the chart. You may even have a 20/15 vision and can see sharper than average images. Don’t think that 20/20 vision is the perfect vision. This determines your visual clarity under standard circumstances and doesn’t determine the quality of your vision under any type of circumstances.Ģ. ![]() If you have a 20/40 vision then that means you need to stand at 20 feet to see anything that a person with normal vision can see from 40 feet. If your visual acuity report says that you have a 20/20 vision then that means you can clearly see objects at a distance of 20 feet 1. 20/20 is just a measurement of how clearly you are able to see at a particular distance. Want to know? Check these 20 surprising facts on 20/20 vision:ġ. In other words, your eyesight is perfect!īut, is this true? Does a 20/20 vision mean that you have a perfect vision? If you were told that you have a 20/20 vision that means, your visual acuity is normal. If you have ever tested your vision, you must remember that the doctor made you read a chart with some letters printed on them. You have probably heard the term “20/20 vision” a number of times.
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