Learn About meditation-induced light visions

"...I had been suffering from insomnia—an unusual experience for me—and, as a result, I'd accumulated a substantial sleep deficit. I can be quite sure about the timing because I knew precisely when I got in bed and when I got out, and, by this criterion, I could not have slept for more than four of the preceding thirty-six hours. The night when the paroxysmal episode occurred, I found myself still awake and alert at four o'clock in the morning. I decided to get in bed and meditate in the hope that this would induce enough relaxation for me to fall asleep. When I concentrated my attention while in this sleep-deprived condition, the familiar light visions begin to flow. I noticed that the phosphenes seemed to be unusually bright, but then suddenly everything changed..."