well, i'ts gone today. i definiately wasn't staring into a bright light but i do have a history of migraines. but they are very different - i get the weird moving thing in both eyes the same. this was like a bright dot of light that i could only see upon blinking and just after. i called my eye doctor and she didn't seem too concerned. she did tell me to look at the ansler grid on my computer and i could still see where the spot was on that. but i can't see it when i blink anymore.
i'm still quiet worried by all this as my mother went blind from macular generation when she was in her late fifties.
It could be an ocular migraine, or flashes from a retinal tear, or perhaps you were staring into a bright light. If it doesn't go away in a few hours, you should go to see an eye md ophthalmologist to have it checked out.
MJK MD