Since I was very young, I have seen what I have always called a "vortex" in my vision. This tends to happen when it's bright outside, but it sometimes happens in dimmer situations. It kind of looks like that Microsoft stars screen saver, but not coming towards me; rather the dots seem to be draining into some point. I cannot look directly at this, as it is more in my upper peripheral vision and if I actually do try to look at it, it simply moves with the rest of my vision.
I have grown some cysts in my jaw over the years, but CATscans for these occasions revealed no brain tumors, although we never were checking for them. Still I think my brain was scanned in the process and someone would have noticed. I also have pretty blurry vision. However I have always had a very vibrant imagination and on a couple of occasions, while deeply relaxed, have started to hear voices speaking gibberish, gorgeous music and an intense ringing and feel as though I am about to float out of my body. This always catches me off guard and in fear I force myself down, although in my most recent experience it took quite a bit of willpower to get down. I always regret it after;P
Also I have some instances of seeing future occurrences in my dreams and when I was very young I was able to fix our crappy TV by "hitting" it with my mind. But then again I was young and I had just seen Matilda I think. The point is there is a bit of a history of strange occurrences with me, probably not much stranger than the average person, but this "vortex" in my vision is something very peculiar. It generally shows up when I am feeling very relaxed and "empty-minded". I just don't quite know what to make of it. Other than needing glasses, my eyes are healthy.