I found your post while searching for "EEG visions." I had an EEG last week and was seeing bizarre geometric patterns. With each change of the light's pulsation pattern, I got new patterns. Very psychedelic. On a couple of the tests I saw strange churning pictures that reminded me of the closing scenes of 2001 The Space Odyssey. I wasn't sure if this was what everyone experienced during the test, or if it was indicative of some problem. Yours was the only reaction I found similar to mine. You seem to be fine, so I'll conclude we're just special somehow. When I see my doctor next month, I'll get his take on it and post again.