Which method is most commonly used to assess visual acuity?

The Snellen chart is the most widely recognized and utilized method for assessing visual acuity. It employs a series of letters or symbols arranged in rows of decreasing size, allowing clinicians to determine the smallest size that a patient can read at a standard distance, typically 20 feet (or sometimes 6 meters in metric). The results are expressed as a fraction, where a lower number indicates better visual acuity; for example, 20/20 vision is considered normal vision.

The use of the Snellen chart is widespread due to its historical significance and the ease with which it can be administered in both clinical and educational settings. Other methods, while effective in specific circumstances, do not have the same level of universal application. For instance, the Amsler grid is primarily used to detect macular degeneration and assess central vision, rather than for comprehensive visual acuity testing. The Snead test is less commonly referenced and is used in specific pediatric contexts. The LogMAR chart, though more precise in some aspects and useful in research settings, is not as prevalent in everyday clinical practice as the Snellen chart. Thus, the Snellen chart remains the standard tool for evaluating visual acuity among the options provided.