Confrontation Visual Field Tests
At your eye doctor, they will likely perform a simple visual field test called a confrontation visual field. In this test, the patient and doctor sit across from each other at eye level. The patient covers one eye, and the doctor holds up a certain number of fingers in the peripheral vision. If the patient can correctly identify how many fingers are being held up, the visual field is said to be grossly full – or relatively normal.
This is a quick test to check for major visual field loss or large blind spots. A common cause of these visual field defects is a stroke which affected part of the vision pathway in the brain.
Amsler Grid Vision Test
Another quick visual field test is the Amsler grid. This test only checks the very center portion of the vision. For the Amsler grid test, a card with a center dot and grid is held about 12 inches away from one eye with the other eye covered. The patient looks at the center dot and must be able to clearly see the boxes and lines around it.
If there are any lines that are wavy or boxes that are missing, this indicates a central vision defect. A common cause of this type of defect is macular degeneration.
Automated Visual Field Test
If there is any reason to suspect a visual field defect, then an automated visual field test may be done. This test is done by a special machine which presents small flashes of lights around your vision. For the automated visual field test, you have an eye covered and are looking into a large bowl with a center target. As the light flashes around your vision, you push a button when you can see it.
This allows for a much more detailed and precise measurement of the visual field. An automated visual field can test for a threshold stimulus – which is the lowest level of light that can be seen half of the time. Threshold visual field tests are considered to be the best method to analyze a patient’s visual field.
There are many conditions which will show a defect on an automated visual field test including glaucoma, retinal vein occlusion, and even ptosis, or a droopy upper eyelid.
Benefits of Visual Field Tests
Visual field testing allows for an optometrist to determine how far into the periphery you can see. This is an important ability for tasks such as driving. Many states even require a visual field test before issuing a driver’s license. Beyond determining the size of your peripheral vision, visual field tests can be among the first tests to pick up on many different conditions.
Our optometrist at Eye Contact in Acworth, GA excels in prescription of glasses, contact lenses and the diagnosis of a variety of eye diseases. Call our optometrist at (770) 529-1925 or schedule an eye exam appointment online if you would like to learn more about or having your visual field tested. Our eye doctor, Dr. Wes Mobley provides the highest quality optometry services and eye exams in Acworth, Georgia and its surrounding areas.