Discuss PGroot's answer to: Why do I see flashes of light?

If you see flashes of light in the daytime, and you can't identify a source like reflections off passing cars, you might have a detached retina.  You need to see an eye surgeon immediately.

If you see flashes of light in the night sky, like streaks, it could be meteors.  If you see flashes and hear bangs, it's probably fireworks.