| This is the
same chart that your doctor uses to determine your visual acuity.
The normal height for the letter A is 88 mm, and the viewing
distance is 6 meters.
To properly view the chart on your monitor:
The final number is the distance (in meters) that you should stand from the monitor. For information on using the chart to determine your visual acuity, see "How Visual Acuity Is Measured" in the MD Support Library.