When the vitreous gel pulls or tugs (causes traction) on the retina, it creates nerve impulses that appear as flashes of light. The flashes are easier to see when you are looking at a dark area. They may come and go.

Flashes of light do not always mean that you have a retinal problem. They often are harmless. They may also be a symptom of a migraine headache. If you see flashing lights for the first time, or if they are different from any you have seen before, call your doctor immediately.