A person with 20/25 vision can stand 20 feet from an eye chart and see the same detail as a person who has 20/20 vision that stands 25 feet from the same chart, according to Divyesh Eye Hospital. The term "20/25 vision" is used to describe the quality of a person's vision compared to someone with 20/20 vision, which is considered “normal” or “average” vision.
Divyesh Eye Hospital explains that 20/20 vision is not necessarily “perfect” vision although some people believe that to be the case. Rather, this figure is used for comparison purposes. Some people can see better than 20/20. For example, someone with 20/15 vision can see at 20 feet what the average person can see at 15 feet. Alternatively, someone with 20/40 vision must stand 20 feet away from the eye chart to see the same amount of detail that a person with 20/20 vision can see at 40 feet.
These comparisons have several practical uses, says Divyesh Eye Hospital. For example, they are used to determine the cut-off for legal blindness, which is 20/200 in the United States. They are also used to determine eligibility and licensing requirements for certain occupations. To obtain a pilot's license, 20/20 vision is commonly required. One must have 20/40 vision to gain a driver’s license without the requirement of corrective lenses, and 20/80 may be used as a qualification for special education assistance.