The visual field test checks the range of your peripheral vision by measuring the ability to see pinpoints of light that flash inside the testing globe. The device measures the area that you can see up/down/left/right while the patient focuses straight ahead.
What is the visual field test used for?
- Glaucoma Screening & Evaluation: Loss of peripheral vision is often an early sign of glaucoma. We repeat this test once a year so the doctor can evaluate treatment plans and the progression of the disease.
- Lid Drooping (Ptosis): If your eyelids have started to droop, the visual field can see if you have any loss of vision due to the drooping lid.
- Effects of Medication: We can also test for effects of medications, such as plaquenil, which can affect the central retina.
- Optic Nerve Conditions: The visual field can help evaluate your vision affected by stroke, optic neuropathy, tumors and injury.
What is a normal visual field?
The definition of a visual field is the space or range in which objects are visible to eyes that are fixed in place, focused on an object.
The normal human visual field extends to approximately:
- Inward: 60 degrees nasally
- Outward: 100 degrees temporally
- Up: 60 degrees above
- Down: 75 degrees below
Taking the test:
The testing device is a large globe or bowl, with pinpoints of light that flash on and off during the test. Patients press a button each time they see a light flash inside the globe. The lights flash in varying patterns and different levels of brightness. It’s kind of like a video game!
During the test, the patient is asked to focus on an amber light directly in front of them, so that we can accurately measure the range of vision all around. We test one eye at a time, so the eye that is not being tested is covered with an eye patch. The test takes about 5-8 minutes per eye. Testing time can vary from patient to patient.
If you have questions about any of the tests that we do, please ask us in person, text or send us an email! We are happy to explain how we use each device to better care for your vision.