An ocular migraine is a condition that involves visual disturbances such as flashing or shimmering lights, stars, zigzagging lines, or even blind spots. Approximately one out of every five migraine sufferers experience this phenomenon. It is often confused with the visual aura that often precedes migraine headaches. Ocular migraines can be triggered by many different things; stress, loud noises, monosodium glutamate (MSG), nitrates, caffeine, and several others. The triggers vary from person to person.