By far, the most common type of migraine aura is visual aura. Almost 90 percent of people who suffer from migraine with aura complain of visual aura. This type of aura, as the name implies, causes a wide variety of vision changes and visual disturbances. These visual aura symptoms typically occur right before the full-scale migraine attack begins. Many people consider the visual aura symptoms a warning sign or pre-migraine symptom that the migraine is about to strike.
What causes visual aura?
Visual aura symptoms are blamed on changes in the brain that slowly spread from one area of the brain to another. This change is thought to cause a series of irregular brain activity including abnormal blood flow. These disturbances, called cortical spreading depression, impacts the occipital lobe – the part of the brain responsible for processing vision. Disturbances in the occipital lobe are believed to cause what are sometimes called illusions or hallucinations related to visual aura. Different people report seeing different things when they experience visual aura. Some have described it as looking like the television snow when the reception is fuzzy. Others report seeing certain geometric shapes or patterns or simply a halo of light.
A 1996 study of 163 migraine with aura sufferers reported the following visual aura symptoms:
- Seeing zigzag lines, 81 percent
- Flickering light, 87 percent, also called fortification illusions
- Pain on one side of head, 69 percent
- Vision changes starting in the middle of the eyesight, 62 percent
- Vision changes starting in the peripheral vision, 28 percent
- White is the color seen, 47 percent
- Rainbow colors seen, 12 percent
Other visual aura symptoms
- Seeing spots, stars, halos, circles, lines, other shapes or colors
- Blurry vision
- Loss of vision
- Cloudy vision
- Other vision changes
- Seeing three-dimensional effects
- Seeing dark areas
Keeping track of your migraine attacks and your visual aura symptoms will help control and perhaps even lessen the attacks. The best way to record your symptoms is to keep a migraine journal. This journal should contain very detailed information about your activities in the day before your migraine symptoms begin. You should also write down all symptoms you experience, how long they last and their intensity. That way when you see a migraine doctor, the doctor can help you figure out any pattern to your migraine attacks or if you have particular migraine triggers.