Your visual field is how much you are able to see around you. It consists of your central (front) vision and your peripheral (side) vision. A visual field test generates a map of your visual field. This map shows where you can see, as well as where you may have an issue seeing things. Ophthalmologists use a visual field test to find and monitor specific eye problems, such as glaucoma.
What happens in a visual field test?
Your eye doctor or a technician will test both of your eyes individually. He or she will put a block over the eye not being tested. You will sit at the edge of a big, bowl-shaped device called a “perimeter.” Your chin will be in a chin rest to stop you from looking around or moving your head.
You will be asked to look at a spot directly in front of you. A computer will play an audio recording, sometimes followed by a flash of light. Any time you see a light, you simply press a button.
In one test, lights move from outside your visual field towards the middle of your vision. As soon as you can see the light, you press the button.
In the other type of test, lights suddenly appear in different areas on the monitor. They will not move from one area to another. When you see them, you press the button.
It is important to keep looking straight forward. Do not adjust your eyes to look for a light. Also, do not worry if you have an issue seeing some of the lights. This is not abnormal, it is expected. The test is designed to use very dim lights so your opthamologist can determine your full range of vision.
Say something if you get drowsy during this test. The technician can pause the test until you are ready to start again. After you are done with the visual field test, your ophthalmologist will talk with you about the results.
A visual field test measures how much you are able to see around you. Ophthalmologists often use this test to diagnose and monitor eye issues.
To take the test, you sit at a device called a perimeter with one eye blocked with an eyepatch. When you see a light appear on a screen, you just have to press a button. The test is repeated using the eye that was previously blocked.
Your ophthalmologist will tell you how frequently you should have a visual field test.
Visual field tests may be a normal part of your treatment.
Depending on your eye problem, your ophthalmologist may want you to have a visual field test 1-2 times annually. This helps them monitor changes in your sight and make any needed treatment changes.