visual acuity

visual acuity is a measure of how well a person can focus on an object. to test visual acuity, the person may read letters or symbols on a chart from the top down, line by line, covering first one eye and then the other.

a visual acuity score is a ratio comparing the person's performance to that of people who have "normal" vision.

for example, a person who can read what people with normal vision can read at 20 ft (6 m) has 20/20 (6/6) distance vision. the larger the second number, the worse the vision.

if vision is 20/40 (6/12), the person can read at 20 ft (6 m) what people with normal vision can read at 40 ft (12 m).
if vision is 20/60 (6/18), the person can read at 20 ft (6 m) what people with normal vision can read at 60 ft (18 m).

this information does not replace the advice of a doctor. healthwise, incorporated, disclaims any warranty or liability for your use of this information. your use of this information means that you agree to the terms of use and privacy policy. to learn more about healthwise, visit healthwise.org. © 1995-2022 healthwise, incorporated. healthwise, healthwise for every health decision, and the healthwise logo are trademarks of healthwise, incorporated.

advertisement

visual acuity

advertisement