This is kind of a weird question.  Cannot find anything on line, or in books.  when I sit in meditation,  I sit zen style with eyes about half open, for various reasons,  but when I wake up at night, or early in the morning, (I wake up at 4 am to meditate),  I usually lay in bed, for a few min's in a kind of meditative state,  with eyes closed.   This was a kind of intuitive thing that I discovered, and found that if one stays in a open state of mind without thinking,  images form in the closed eyes. Starts with colors merging, and then changing to shapes, images, and then other life forms.  then changing to very clear pictures. The closest I can get to finding information on this, is what western lucid dreamers call W.I L D or Waking Induced Lucid dreaming, where one of the techniques is to do this exercise with closed eyes, when one first goes to bed in a meditative state.  Not trying to accomplish lucid dreaming, as my dreams are already lucid..........  But this WILD technique is the only other one i have heard of.   Any information or experience in this matter? Of course, I have been around the block long enough to not become attached or indulge in this kind of thing.  Like most odd things i have experience, i just watch them,  and let them go,  but this is interesting none the less.