I've had them for 30 odd years. The Doctors claim it's due to my MS. Never have a migraine or pain with the auras. Just a large wiggly worm of flashing lights in both eyes. Kinda pretty but sure as hell it's nerve racking as I never know if it's going to be long lasting.
I can have couple per week lasting 10-30 minutes then go couple weeks with none. When it happens I just relax and close my eyes and it passes. Of course I can't drive when it happens.