| a term used to express normal visual acuity, the clarity or sharpness of vision, measured at a distance of 20 feet. Having 20/20 vision, means a patient can see clearly at 20 feet what should normally be seen at that distance. If a patient has 20/100 vision, it means that the patient must be as close as 20 feet to see what a person with normal vision can see at 100 feet. 20/20 vision does not mean perfect vision, only indicating the sharpness or clarity of vision at a distance. Also known as the standard for Snellen Acuity in the United States. |