Migraine headache is a common neurological condition that occurs in about 20% of the population and in 50% of women. It is not clear how a migraine works, but it is believed that the basic cause is an abnormality of serotonin, which is a chemical used by the brain cells. During a migraine, changes in serotonin levels cause the blood vessels in the brain to constrict. This decreases oxygen supply in the brain. In rare cases, a stroke is possible.

Certain foods like aged cheese, chocolate, red wine, and caffeine may trigger migraines. Hormonal changes during pregnancy, menopause, and menstrual periods also are associated with migraines. People with migraines often have a family history of headaches or prior histories of motion sickness.

Symptoms of migraines include nausea, sensitivity to light or sound, pounding pain, and some visual symptoms, including a blurring spot, an expanding border often described as zigzag lines or shimmering, and vision loss in only one eye. Rare symptoms include double vision or a change in pupil size.

Treatments first seek to avoid any known factors that precipitate a migraine attack, including environmental factors, medications, and food. Medications for migraines may be prescribed. If migraines are severe, medication on a regular basis may be necessary.

(c) 2007 The American Academy of Ophthalmology