The Gold Standard

Did you know that 20/20 vision is not the perfect vision? It’s the standard measure for normal visual acuity, which is how sharp or clear your vision is at a distance. Eyeglasses or contacts help us have 20/20 vision. But what does the 20/20 fraction actually mean?

Reading the letters
The most common eye chart is the Snellen, with its familiar rows of letters in decreasing sizes. While you stand or sit 20 feet from the chart, you are instructed to read each row until you no longer can. (For an interesting history of the Snellen, go to https://atlanticeye.com/2022/11/do-you-know-snellen/)

Understanding the numbers
The top number is your distance in feet from the eye chart. The bottom number is the distance at which a person with normal eyesight can read the same line. So when your vision is 20/20, it means you can see what an average person can see on an eye chart when they are standing 20 feet away. If you have 20/30 vision, it means your vision is worse than average, because from twenty feet away you can only read letters most people see from 30 feet away. Conversely, if you have extra-sharp 20/15 vision, you can see a line in the eye chart at 20 feet that the average person can only see from 15 feet away.

The 20/20 goal
In most cases, blurry vision is caused by a refractive error like nearsightedness, farsightedness, or astigmatism. According to the American Academy of Ophthalmology, only about 35% of all adults have 20/20 vision without glasses, contact lenses, or eye surgery. With correction, about 75% of adults achieve 20/20 vision. In most states, you need 20/40 vision or better for an unrestricted driver’s license. People are “legally blind” if their vision with glasses or contacts is 20/200 or worse.

Beyond visual acuity
Even if you are fortunate enough to have 20/20 vision, you need eye exams as you age. Your Atlantic Eye physicians recommend that you get a baseline eye examination by age 40, when early signs of disease or vision changes may happen, or earlier if you notice any problems with your vision or eyes. Your total eye health is always our gold standard of care.