The visual field test maps out for us your entire field of vision, from the center all the way out to the periphery.  It is a diagnostic tool for many diseases, including glaucoma, optic nerve problems, retinal disease, and even neurological issues between the back of the eye and the vision center in the brain.  Your eye doctor has been trained to look at a problematic field’s appearance and extrapolate where the problem lies.  The test itself involves testing each eye separately.  The patient pushes a button when they see lights of varying brightness appear.  It’s basically a boring video game, but with a purpose.