Retinal migraine (also known as ophthalmic migraines, or ocular migraines) is a medical condition that affects the eyes by causing vision loss in one eye for less than 1 hour, usually for about 10–20 minutes. When these retinal migraines happen they can also cause a headache, either a "diffuse" headache which is a headache that causes pain which is spread out and hurts a person's whole head, or, a "unilateral" headache, which is a headache that causes pain on one side of a persons head either, the left side or the right side.