Retinal migraine
It is believed retinal migraines are caused by vasospasms of the blood vessels of the eye in the area of the retina. The retina is at the back of the inside of the eye. In medicine a spasm is a sudden constriction or tightening of muscles that is involuntary - a person does not control them they move on their own. Muscle spasms can happen in different muscles of the body, like when a person's leg or eye twitches. The twitching is caused by the spasms.