“What is a visual field test?”

It is a simple automated test of peripheral vision. Like a hearing test we have all had in school, but for the eyes.

It is a test done at the office one eye at a time to check the peripheral vision. The patient is given a clicker and told to push it when they see a flashing light. It requires no anesthesia and typically takes around 5 minutes. It is a common test for glaucoma, but may need to be repeated.

Frank Cao

A visual field is a computerized test that checks and compares your peripheral vision from people your age and sex in the population. It is the gold standard for glaucoma evaluation.

Glaucoma is a problem with the pressure inflating the eye. Sometimes the pressure can rise too high, causing injury to the optic nerve in the back (where all of the nerve fibers from the retina (the film lying against the inside back that takes the picture and then sends the image to the brain through a hole in the back of the globe= the optic nerve). When the pressure stays too high, the nerves are progressively eroded, causing loss of vision that is most often worse in the peripheral vision. Therefore glaucoma is followed by three tests, the measurement of the pressure inflating the eye, pictures taken of the optic nerve, and measurements of ability to see spots of light flashed in the peripheral vision (your head is placed in a big white bowl and the spots are flashed around the sides, with you responding by pushing a button when you see each one.

A visual field tests the transmission system that sends recorded vision to the brain. It is the ganglion cells and nerve fibers that get damaged in glaucoma and cannot transmit the vision to the brain vial electron recording. As a person who takes the test, they have a button to push every time they see a test light. You are looking into a background lighted large half bowl. If not seen, a negative picture is formed. It shows what is damaged and how deep is the damage. There is no pain or discomfort.  It is a visual recording map.

It is an automated test to check peripheral vision, i.e., your side vision. This is affected by glaucoma.

Visual fields are a great way to see if there is any reduced signaling from the retina to the brain in the central 30 degrees of vision. Glaucoma damages the optic nerve as it leaves the eye. The nerve fibers leave the eye in bundles through the optic nerve and can be damaged/die off over time (the disease is called Glaucoma). One way to slow/stop this process is to lower the overall pressure inside the eye. Reducing the eye pressure can be done with drops, lasers, and a variety of surgeries. When the optic nerve looks like it has damage (cupping or notching of tissue), The visual field test and OCT scan is performed to determine whether medical treatment/interventions are needed. In early Glaucoma, the visual field will be normal. If there are already defects on the visual field, the Glaucoma is beyond the early stages. The visual field tests one eye at a time. The patient looks straight ahead at a fixation light and is instructed to push a button every time he/she sees other lights (small/big/bright/dim) anywhere else in the vision. As Glaucoma develops, you lose the ability to see the small/dim lights in certain areas and can eventually cause tunnel vision.

He is placed in a machine with a large bowl in front of him. He is instructed to stare at a red light. White lights are randomly shone, one at a time in various places on the bowl and he must press a button when he sees a light without looking anywhere else but the central red dot.

Visual fields test how wide your field of vision is. We have central vision and Peripheral vision. These tests are designed to chart your field of vision especially the Peripheral vision which is lost in glaucoma leading to tunnel vision

It tests for peripheral vision in glaucoma patients. It is used for various other conditions such as plaquenil toxicity, retinal vein and artery occlusion, optic nerve head Drusen, etc.