Measure the green "standardization bar" in centimeters on the computer monitor. Then stand in a position back from computer monitor so that your eye is this same number of feet from the screen. i.e. if the green bar measures 10 centimeters in length, you should stand back so that your eye is 10 feet from the screen.
Vision testing should be performed on each eye separately, wearing distance eyeglasses if required. There are six lines on the screen, you should note the last line number in which you can read more than half of the letters.

The middle letter of the top line is equivalent to 6/60. The "T" and the "B" on the top line are equivalent to 6/36. The second line is 6/18. The third line is equivalent to 6/12. The bottom three lines represent 6/9, 6/6 and 6/5. These are considered to be "normal vision" with the 6/6 line being the traditional normal vision line. If you are able to read the last line it means that you are standing too close to the monitor.

This vision test can only be considered a screening test. A variety of factors such as lighting, glare, monitor quality may have an effect on the results of this test. For final assessment consult your eye surgeon.