What type of vision test is typically used to measure visual acuity at various distances?

The Snellen chart is specifically designed to measure visual acuity at different distances. This chart displays letters or symbols of varying sizes, allowing an optometrist or technician to assess how well a person can see at a standard distance, typically 20 feet in the United States. During the test, the individual reads the smallest line of letters they can identify, providing a quantifiable measure of their vision clarity and sharpness.

The accuracy of the results from the Snellen chart test is paramount for determining if a patient requires corrective lenses or further evaluation. It is a fundamental part of optometric practice because visual acuity is a critical component of overall eye health and function. In contrast, other tests listed, such as color vision tests or refraction tests, serve different purposes, such as assessing color perception or determining the appropriate lens prescription, respectively. A tonometer reading, meanwhile, measures intraocular pressure and is not used to evaluate visual acuity.