Check your screen display: the top letter E (in the eye chart, below) should be almost 3 1/2 inches (88.7 millimeters) tall. The matching height is required to determine the real size reference. It should be possible to adjust the resolution and zoom level on your computer screen to match the desired criteria. Internet Explorer is recommended for its custom zoom, which allows fine-tuning. (See More info and details.)

This Eye Chart is styled after the classic Snellen eye chart (PDF file) and sized in proportion to its original computer-generated specifications. Directions: Stand 20 feet in front of the Eye Chart displayed on your computer screen. Do not squint as you read each set of letters. You will have to scroll down to see all the sets, but do not peek at the screen while scrolling. (If preferred, someone else can scroll down the screen for you.) Click on the box located on the right of the last set of letters that you can read accurately. (Reading a set of letters accurately means identifying most of the letters in a set.) When finished with the test, press SUBMIT at the bottom of the chart to see your RESULTS. The final designation of your visual acuity is printed in red on the RESULTS page. (The test's ability to describe your vision is approximate; for best results see an eye care professional.)