Final answer:
The Snellen chart is used in medical offices to test visual acuity by using a standardized set of Roman letters of decreasing size to approximate a person's visual sharpness.
Step-by-step explanation:
To check visual acuity in the medical office, a Snellen chart is used. This chart is known for its standardized arrangement of Roman letters in decreasing size to be viewed at a distance of 20 feet. When a person is tested, having results such as 20/60 vision means that the smallest letter they can read at 20 feet could be seen by a person with normal visual acuity from 60 feet away. The chart is used to provide a rough approximation of a person's acuity in relation to the normal standard, which is based on the angle of vision taken up by the letters.