Visual Acuity: What is 20/20 Vision?
20/20 vision is a term used to express normal visual acuity (the clarity or sharpness of vision) measured at a distance of 20 feet. If you have 20/20 vision, you can see clearly at 20 feet what should normally be seen at that distance. If you have 20/100 vision, it means that you must be as close as 20 feet to see what a person with normal vision can see at 100 feet.
Having 20/20 vision does not necessarily mean you have perfect vision. 20/20 vision only indicates the sharpness or clarity of vision at a distance. Other important vision skills, including peripheral awareness or side vision, eye coordination, depth perception, focusing ability and color vision, contribute to your overall visual ability.
Neural factors that limit acuity are located in the retina or the brain (or the pathway leading there).
Some people can see well at a distance but are unable to bring nearer objects into focus. This condition can be caused by hyperopia (farsightedness) or presbyopia (loss of focusing ability). Others can see items that are close but cannot see those far away. This condition may be caused by myopia (nearsightedness).
A comprehensive eye examination by a eye doctor can diagnose what is affecting your ability to see well. In most cases, your ophthalmologist can prescribe glasses, contact lenses or a vision therapy program that will help improve your vision. If the reduced vision is due to an eye disease, you may be prescribed ocular medication or another treatment.
MYTH: Having 20/20 vision means that the eyes are perfect.
FACT: The term "20/20" denotes a person with excellent central vision. But other types of vision-such as side vision, night vision, or color vision might be imperfect. Some potentially blinding eye disease, such as glaucoma or diabetic retinopathy, can take years to develop. During this time, they are harming parts of the inner eye, but the central vision can remain unaffected.