For the pathologic fear of light see the article on -phobia

Photophobia is a symptom of excessive sensitivity to light and the aversion to bright light. Patients with photophobia usually seek the shelter of a dark room. Patients may develop photophobia as a result of several different medical conditions, related to the eye or the nervous system. Photophobia of acute onset should be reviewed by a doctor as soon as possible as this could be a sign of meningitis.

Common disorders which lead to photophobia are migraines, meningitis, encephalitis, conjunctivitis, and iritis.