A visual field test measures the sensitivity of your eyes throughout your field of vision. It is a straightforward test, painless, and does not involve eye drops. Essentially lights are flashed on, and you have to press a button whenever you see the light. Your head is kept still and you have to place your chin on a chin rest. The lights are bright or dim at different stages of the test. Some of the flashes are purely to check if you are concentrating.
Each eye is tested separately and the entire test takes 10-15 minutes, typically about 3 minutes per eye of actual test time. Normally the test is carried out by a computerized machine, called a Humphrey Visual Field Analyzer.