What is a visual field test?
During a routine eye exam, some eye doctors may want to determine through visual field testing the full horizontal and vertical range of what you are able to see peripherally. This range is commonly referred to as “side vision.”
If you can’t see objects in an appropriate portion of your field of view, then you may have a blind spot indicating vision loss.
Why check your peripheral vision?
Visual field testing can lead to early detection and treatment of disease. In the case of glaucoma, visual fields play a major role in identifying visual field defects and evaluating the efficacy of the therapy used to control the disease process.
Many eye and brain disorders can cause peripheral vision loss and visual field abnormalities.
Brain abnormalities such as those caused by strokes or tumours can affect the visual field. In fact, the location of the stroke or tumour in the brain can frequently be determined by the size, shape and location of the visual field defect.
What happens in a field test?
While your head is held still, usually with a chin rest inside a large bowl-like instrument, you stare at a source of light straight ahead. Random lights of different intensities are flashed in your peripheral field of vision.
You then press a button or use other means to indicate your response when you perceive the computer-generated light suddenly appearing in your field of view.
You may hear a field test also be referred to as a click test due to the button that you press.
A field test is quick, painless and non-invasive - totally safe for all ages.