In the darkroom, after you first turn of the lights, there can appear to be some sort of afterglow; enough to make you think there is a light source somewhere. Given a few minutes, this will go away (if the room is actually totally dark). Closing your eyes can somehow make you feel more secure that the room is actually dark. I can think of no physiological reason for this, (the closing of eyes, not the afterglow, as that is normal) so assume it is psychological.
I no longer close my eyes.
This is my experience...