Could be nothing serious but I would talk to the doctor about it to rule out things like TIAs, MS, etc.
It could be something called an ocular migraine, but I agree with Gina to go get checked out just to be sure.
Since I hit menopause I sometimes get these types of migraines, which occur in the vision center of the brain. I see flashing lights which go away in about ten minutes, then I might have a mild headache or no pain at all. But I always feel tired afterwards and have to take a nap.