A Snellen chart measures how sharply you can see by having you read rows of letters that shrink line by line from top to bottom. The result is written as a fraction like 20/20 or 20/40, and understanding what that fraction means is simpler than it looks.

Learn how to use a Snellen chart correctly, understand your vision score, and know what those results actually mean for your eyesight.

Wall-mounted Snellen charts are inexpensive and are sometimes used for approximate assessment of vision, e.g. in a primary-care physician's office.

One of the most common tools used in eye examinations is the Snellen chart, a fundamental component of vision assessment. In this comprehensive guide, we’ll explore what a Snellen chart is, its history, how it’s used, and how to interpret the results.

Learn how the Snellen chart measures visual acuity, what those fractions like 20/20 actually mean, and what the test can and can’t tell you about your eye…

To use the Snellen chart, stand 20 feet away and read the rows of letters, starting at the top and working your way to the bottom. Do this while covering one eye and reading the chart with your uncovered eye. When you finish with one eye, restart the test with your other eye uncovered.

Discover how to use a Snellen chart for visual acuity testing. Our guide provides step-by-step instructions and tips for accurate measurements.

The Snellen chart is a standardized letter chart used to measure distance visual acuity. Herman Snellen, a Dutch ophthalmologist working at the Netherlands Hospital for Eye Patients in Utrecht, introduced it in 1862.

Discover how the Snellen Eye Chart helps measure your visual acuity. Learn what those letters mean and why regular eye tests are essential.

To use the Snellen eye chart, you cover one eye and read aloud the letters on the chart, starting at the top and moving downward. The smallest row of letters you can read accurately determines the visual acuity of the uncovered eye.