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)
