UMMS: Vision Strength Calculator
UMMS Health Calculators

Is it time for eyeglasses?

Nearsightedness, or myopia, is a condition that affects nearly 30 percent of the U.S. population. When you are nearsighted, you may have trouble making out details on road signs or identifying people from a distance.

Some evidence suggests that myopia is hereditary, although it may also be caused by the stress of too much close-vision work.

This vision strength calculator will help you to determine if you need glasses for myopia.

You may take this test with or without corrective lenses. This vision calculator is made to test only one eye at a time.

This is only a screening tool, and cannot replace a professional eye exam.

This test should be used as a guideline, and is based on guidelines developed in partnership with The School of Optometry, University of California Berkley and with public information supplied by the National Eye Institute.


Before taking this test, you will need to test your computer. You will need a dollar bill, or a ruler, to measure a line displayed on your screen. (This will be used to determine which settings are right for your computer.)

Hold a dollar bill up to the screen and find the colored bar that is the same length as the width of the dollar. (Or find the line that is 2½ inches (6.4 cm) long.)

Click on the bar that is closest to the correct size:












The information on this Web site is provided as a public service by the University of Maryland Medical System, a regional health care delivery system that includes an academic medical center (the University of Maryland Medical Center in downtown Baltimore) as well as five community and specialty hospitals and outpatient sites throughout Baltimore and central Maryland. This information is not intended to be a substitute for individual medical advice in diagnosing or treating a health problem. Please consult with your health care provider about your health care concerns. If you would like to make an appointment with a University of Maryland physician, please call 1-800-492-5538.