I've drafted an essay, that I plan to publish, about the retinas' limits in ROYGBIV. I've done closed eye experiments, with lamps on in a room, spun around several times to lose orientation, and still been able to detect the location of the lamp very precisely, before opening my eyes. The angle is very precise, and the ray line enters the skull, if you stop turning/spinning off the face axis, from not the eyeball sockets, but right through the skull into the thalamus, seeing the red tinted lamp radio/IR energy. Thus, you might agree, that the red tint we sometimes see when closing eyes, makes more sense as not blood (properly more blue or cyan internal, anyhow, if it were blood, and I believe it is not at all), but infrared between red and radio frequencies. Thanks for the interesting introductory article/essay. I enjoyed reading it. You've inspired me to finish my essay. Thanks!