UraniumMonk
I mostly see greens and blues, but they are very indistinct and if I focus too hard on them they just go away. I've heard this effect is caused by the vision processing portion of the brain basically “getting bored” when there is a lack of stimulus. The same thing can happen if you are in an extremely quiet place.
I guess that's why you get ringing in your ears if there is no sound.
no stimulus.
And if you see red, perhaps it's just your blood vessels in your eyes.
or light reflecting off of dust in the air
EDIT: Hang on, please tell me what this has to do with the paranormal.
This isn't exactly a rare or unusual phenomenon.