Many individuals with headache will consult an optometrist, often before any other health professional, in the belief that their symptoms may represent a primary ocular problem. Various eye disorders are recognised to be possible causes of headache, including acute glaucoma, inflammatory ocular disorders, and refractive errors (International Headache Society Classification Subcommittee 2004). This module reviews the clinical features of migraine and some of its variants, with emphasis on visual phenomena, and discusses pathophysiology, differential diagnosis, and management.