An ocular migraine (also called an "ophthalmic migraine," "optical migraine" or "migraine aura") produces this disturbed vision, with or without an accompanying headache. Changes in blood flow to the brain are thought to be the cause. The visual distortion starts in the center of the field of vision. It might appear as a bright dot, dots, or a line that can seem to move and disrupt your ability to see properly, as if you were looking through a pocked or cracked window. It's painless and causes no lasting damage. Individuals seem to have different triggers (ranging from chocolate, caffeine and alcohol to stress). A headache, possibly severe enough to cause nausea, sometimes follows.To see more details visit, health.msn.com/health-topics
