What is a Visual Field Test?
A visual field test is a test performed to measure an individual’s scope of vision. This scope of vision refers to their central and peripheral vision. This type of testing is done to map the visual fields of each eye. The purpose of a visual field test is to detect areas of dysfunction in central and peripheral vision which may be caused by a variety of medical conditions, such as glaucoma, brain tumors, stroke and other neurological deficits.
Visual field testing is conducted using a visual field screener. This bowl-shaped device will require the patient to stare at the center spot and response when they see a light flash in different areas of the bowl. The test is performed one eye at a time, in order to map out exactly which areas of each eye’s vision field are strong or weak.
How to Perform a Visual Field Test
There are two ways of performing this test. Static testing is the most commonly used method of visual field testing. In this method, the patient may be given a clicker or button to press each time that a light quickly flashes within their field of vision. The flashes of light will not move, but will only remain visible for a very brief moment. In the early stages of the test, lights will be faint and continue to grow in brightness to record sensitivity of the visual field.
The second method, known as kinetic testing, uses the same spots of light, but will move the light from the outside of your visual field towards the center, and the patient will be asked to indicate immediately when they first are able to see the light enter their visual field.