Anyone ever had these? I'm having one at the moment, which is what's prompted me to post. I started getting them about a year ago, and went through a phase of having a couple a week, but haven't had one for a few months now. I was worried at the beginning because I've never had a migraine and these have no accompanying pain, but suddenly I get a bright light at the centre of my vision, that gradually gets bigger into a jagged C shape of flashing black and white triangles, and that grows and grows until it sort of drifts out of my peripheral vision which takes about 20 minutes. Looks like this: Very weird. Reasonably irritating, especially as I was trying to read something. Just wondered if anyone else has these and if you know anything about the cause.