What is a common use of the Snellen chart in eye examinations?

The Snellen chart is primarily used to measure central visual acuity, which refers to the sharpness or clarity of vision at a distance. It consists of letters of varying sizes and is typically displayed at a standard distance, allowing healthcare professionals to assess how well a patient can see as compared to standard visual acuity. During the test, patients are asked to read letters from the chart, with results often expressed in a fraction (e.g., 20/20), indicating how well they can see at a specific distance compared to a person with normal vision.

This test is fundamental in ophthalmology and optometry because it helps identify refractive errors, monitor changes in vision over time, and determine the need for corrective lenses. By establishing a clear baseline for a patient's visual acuity, practitioners can make informed decisions about diagnosis and treatment options.