What test is commonly used to measure visual acuity?

The Snellen chart is widely recognized as the standard tool for measuring visual acuity. It consists of rows of letters that decrease in size, which allows for the assessment of how well a person can see at a distance. During the visual acuity test, the individual is asked to read the smallest line of letters they can discern clearly from a specified distance, usually 20 feet. This method provides a clear, quantifiable measure of visual sharpness and is a fundamental component of eye examinations.

In contrast, the confrontation test is more subjective and is used primarily to assess peripheral vision rather than central acuity. Tonometry is a technique for measuring intraocular pressure, which is crucial for evaluating glaucoma but does not assess visual acuity. Retinoscopy is a method used to determine the prescription for glasses by observing the reflection of light in the retina and assessing refractive errors, but it does not measure visual acuity directly. Thus, the Snellen chart is specifically designed for and effectively used in measuring visual acuity in clinical practice.