How do I differentiate between a retinal tear and an ocular migraine?

Flashing lights (photopsias) can happen with both retinal tears and migraines. Lights seen with a retinal tear tend to come and go with no defined length of time. They are usually brief flashes and do not affect vision unless they happen with floaters as well. Retinal tears happen in a specific eye, so the flashes of light only appear in one eye. With migraine, flashes usually last up to 30 minutes. The flashes may grow from smaller to larger and appear in both eyes. You may see a blank spot that diminishes your vision and improves as the flashes resolve. These flashes may be jagged and geometric and happen in rhythm with your pulse. Flashes from migraine usually don’t happen with floaters in your vision as well. You may or may not have a headache or nausea after the flashes.

Although this is how retinal tear and migraine usually appear, it can sometimes be difficult to determine the cause of flashes. A complete eye exam is needed to find out what is causing your symptoms.