From what I've read, symptoms like those are often associated with migraines. Mine apparently haven't been. I've been getting the "scintillating scotoma" part every few years but never the headache part of the migraine. Mine usually finish drifting across my visual field in half an hour or so and leave no other symptoms. I've never tried taking anything for them; usually I don't even interrupt whatever I'm doing.

Here are a few things I've found online about this:

Scintillating scotoma, Wikipedia

Migraine Aura: Scintillating Scotoma (pdf, 1 page)

Googling on "scintillating scotoma" also brings up a YouTube depiction of the phenomenon. It's not much more detailed than some of the animated graphics in the Wikipedia article. I didn't want to post the actual link here because the forum software turns it into a "viewer object" right in the post.