Visual acuity (VA) is sharpness of vision, especially as tested with a Snellen chart. Normal visual acuity based on the Snellen chart is 20/20. It is one of many components of the visual perception sense and is defined as the eye's ability to resolve fine details. VA is a quantitative measure to see an in-focus image at a certain, standarized distance. VA is the most common measurement of visual function that is performed in a clinical setting.

Snellen Chart

The Snellen Chart used to measure Visual Acuity is commonly called the "eye chart". It is shown below but made much smaller for this web site. You should not use it to try to measure your own visual acuity because it is just too small.

See other terms from Glossary of Eye Terminology.