What Does 20/20 Vision Measure?Ģ0/20 vision measures the clarity and sharpness of a person’s vision from a distance of 20 feet. This test helps determine ideal contact or eyeglass lens prescription. The doctor places the chart through different lenses. The doctor displays the letters on a chart or projection, and a person points to whichever direction the letter faces. The test involves identifying which direction the letter “E” is facing. You would typically take a Random E test at an eye clinic. The doctor or nurse will ask you to read all the letters on the chart until they no longer can do so. Once done, you will cover the other eye and repeat the same process. You cover one eye, and an ophthalmologist will request you to read out the letters you can see clearly with the uncovered eye. Usually each row of letters is a different size than the one above it and below it.Ī person stands 14 to 20 feet away to determine how well they can distinguish the letters and shapes, one eye at a time. Letters and symbols are different sizes and arranged in columns and rows. It is customary to find this chart in an eye doctor’s office or a nurse’s office at school. The Snellen chart is a grid of letters or symbols. This test is part of a comprehensive eye exam. The purpose of this test is to determine whether a person is experiencing vision problems. The following are professionals who can perform the test: However, that is simply one aspect of a person’s vision others include peripheral vision, color vision, and depth perception. Visual acuity refers to a person’s ability to distinguish the details and shapes of things they see. How Is Visual Acuity Tested?Ī visual acuity test checks how well a person sees the details of a symbol or letter from a specific distance. If you have 20/20 vision, it means you can see the same amount of details on an object from 20 feet away, just as a person with average vision clarity. Visual acuity is the most common measurement of how a person’s eyes function. That number rises to 75 percent and includes people who benefit from the help of LASIK surgery, eyeglasses or contact lenses. Only 35 percent of adults have 20/20 vision without visual aid or corrective surgery. Other visual skills, such as the detection of colors and peripheral vision, are equally important. The numbers mean that you see objects in focus and in detail at a distance of 20 feet.Īlthough eye doctors classify 20/20 as normal, it does not equate to perfect vision. IntroductionĢ0/20 is a measurement that denotes clear, sharp and normal vision. People with 20/10 vision and 20/5 vision have better eyesight. Someone with 20/20 vision is considered to have normal visual acuity, or normal eyesight.Ībout 35 percent of adult Americans have 20/20 vision, which means they can see objects clearly when standing 20 feet away.Ģ0/20 does not denote perfect vision, and there are other designations for people with better vision than 20/20.
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