How is visual acuity tested?
The examiner will test for visual acuity, the ability to see at a distance, using the familiar Snellen Eye Chart, which starts with one large “E” at the top and has a descending series of smaller letters. A reading of 20/20 means that the person being examined can see at 20 feet what is normal to be able to see at that distance. A reading of 20/60 means that the person can see at 20 feet what it is normal to see clearly at 60 feet. A reading of 20/200 being able to see only the E at the top of the chart means that the person can see at 20 feet what someone with excellent eyesight can see at 200 feet. Legally, blindness is defined as reading of 20/200 or worse. The eye examination also tests the effect of glare or low-contrast conditions on an individuals sight. It includes a test that measures the responsiveness of the outer part of the retina, which does not have as many nerve fibers as the center of the retina. This test is important when glaucoma or a neurological condition is expec
