(An interesting repeat from January 3, 2016) When we blink our eyes closed, we are usually greeted by an assortment of exploding stars, shapes and colors.  When head hits the pillow and it’s dark, there can still be a veritable light show when our eyes close.   The phrase “seeing stars” from a bump on the head or being dizzy refers to these closed eye light phenomenon.  The illuminations you see – when there is no light – are called “phosphenes.”  The term comes from the Greek “phos” (light) and “phainein” (to show). 

When people are deprived of light for long periods of time, phosphenes occur in vision as well — when eyes are open.  Thus phosphenes used to be called “the prisoner’s cinema.”  People who are blind will sometimes press or rub their eyes to stimulate phosphenes (which they can “see”).   While phosphenes have been around as long as the human condition, they were first reported in 1819 by Bohemian physiologist Johannes Purkinje.  Benjamin Franklin was reported to have used an electrical stimulation to cause a closed-eye spectral. 

Trouble sleeping?   Apart from checking out March 19, 2012, just close your eyes and watch the unfolding kaleidoscope of phosphenes.  And breathe deeply. You’ll be asleep in no time.