What is the Snellen chart used for?

The Snellen chart is specifically designed to measure visual acuity, which refers to the clarity or sharpness of vision. It typically consists of letters or symbols that decrease in size from top to bottom. During an eye examination, a patient is asked to read the smallest line of letters they can clearly see, which allows the clinician to determine their visual acuity level, commonly expressed as a fraction, such as 20/20. This measurement is essential for diagnosing vision problems and determining the appropriate intervention, be it corrective lenses or further assessments.

The other options involve different aspects of visual function. Measuring color vision focuses on the ability to perceive colors and typically employs different tests, such as Ishihara plates. Testing ocular pressure is related to glaucoma assessments and makes use of tonometry, while assessing depth perception involves tests often conducted with specialized equipment to evaluate binocular vision and spatial awareness. Each of these tests serves a distinct purpose in the realm of eye care but does not utilize the Snellen chart.