Sep 4, 2013

What does it mean to have 20/20 vision?

Many people think that with 20/20 vision the eyesight is perfect, but it actually means that the eye can see clearly at 20 feet what a normal eye can see clearly at that distance. Some people can see even better – 20/15, for example. With their eagle eyes, they can view objects from 20 feet away with the same sharpness that a normal-sighted person would have to move in to 15 feet to achieve. (The Handy Science Answer Book, compiled by the Science and Technology department of the Carnegie Library of Pittsburgh)