I know the colour change you're talking about. I've heard various things. I'm very sensitive to energy changes so I am inclined to think that what I am staring at is my own energy field. I have read studies that demonstrate when your eyes are closed for a long time and you enter a meditative state, one's peripheral vision is enhanced greatly upon opening the eyes. If you talk to psychics and energy workers (actual ones, and not new age hippie dippies), it is in peripheral vision where observation of phenomenon tends to occur.