Eye defects such as nearsightedness, farsightedness, and astigmatism affect almost half the people in the U.S.
The term “20/20 vision” means a person can see at 20 feet what should normally be seen at that distance. But 20/20 indicates only the ability to see detail clearly; it does not always mean “perfect” vision. For instance, it does not take into account things like peripheral (side) vision and color vision.
