The Snellen Eye Test 20 - An Industry Standard For Measuring Visual Ability

The Snellen Eye Test 20 is a standard by which medical care professionals measure a person's ability to see. Most people know what the Snellen Eye Chart is when they see it, but may not recognize it by name. The top letter on the chart is a giant "E" with lines of random letters that decrease in size. Typically, the person taking the eye test reads the letters on the Snellen Eye Test, 20 feet from the chart, with the goal to see which is the smallest line of letters that the person can read.

Snellen Eye Testing, 20/20 Vision

As a rule, the person taking the Snellen Eye Test will be asked to cover one eye and to read lines of text on the chart with only one eye at a time. The person analyzing the results may start with the optimum line (the line that indicates a person would have 20/20 vision), and work up or down on the Snellen Eye Test to determine the exact visual ability of the person taking the test.

Variations of the Snellen Eye Tests for Children

There are some variations of the Snellen Eye Test. For young children who may not yet know the names of the various letters used on the chart, the entire chart uses only the letter "E." The capital letters are placed so that the legs of the letters are pointing up, down and to each side and children simply point to the direction the legs of the "E" points. This ensures that the Snellen Eye Test provides an accurate result for even the youngest child experiencing visual problems.

If You Fail the Snellen type Eye Test

The goal, of course, is to be able to read a particular line of the Snellen Eye Test, 20 feet from the chart. But if you fail the test, don't worry. It simply means that you've joined the ranks of the millions who need glasses or contacts to help them see more clearly. Check out the many purchasing options on this site for more information about glasses, contacts and other vision products.

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