Visual field testing is a critical part of the neuro-ophthalmic exam and is essential for the evaluation of unexplained visual loss. A visual field test measures all areas of your eyesight, including your side, or peripheral, vision. This crucial test helps your ophthalmologist tell whether there are gaps in your vision. It also helps diagnose your condition, as the test can help find certain patterns of vision loss that may rule out certain conditions or help specify the source of your vision loss.
To take this painless test, you sit facing a bowl-shaped instrument called a perimeter. While you stare at the center of the bowl, lights flash. Each time you see a flash, you press a button. A computer records the location of each flash and whether you pressed the button when the light flashed in that location. At the end of the test, a printout shows if there are areas of your field of vision where you did not see the flashes of light. This test shows if you have any areas of vision loss.
Regular perimetry tests are a key way to see how, if at all, your vision is changing over time. It can also be used to see if your treatments are successful at improving your vision or preventing further vision loss.