Scotoma

A scotoma (plural scotomata) is a "dead" section of the visual field, rather like a dead pixel on a TV screen. These can be caused by strokes or a coup coutracoup head injury where the brain has impacted both sides of the brain following an abrupt trauma to the head. There are many kinds of scotomata: central, peripheral, hemianopic, paracentral, bilateral, and absolute. These refer to varying degrees and locations of scotoma. Scintillating scotoma is also known as the visual aura that frequently precedes a migraine headache.