phosphene

noun

phos·phene | \ ˈfäs-ˌfēn

Definition of phosphene

: an impression of light that occurs without light entering the eye and is usually caused by stimulation of the retina (as by pressure on the eyeball when the lid is closed) or by excitation of neurons in the visual system (as by transcranial magnetic stimulation) Early studies have demonstrated that direct electrical stimulation to neurons of the visual system will cause a subject to perceive points of light (phosphenes).— George Scarlatis

Phosphenes Is the Word You're Looking for

Phosphenes are the luminous floating stars, zigzags, swirls, spirals, squiggles, and other shapes that you see when closing your eyes tight and pressing them with your fingers. Basically, these phenomena occur when the cells of the retina are stimulated by rubbing or after a forceful sneeze, cough, or blow to the head. The word phosphene comes from the Greek words phōs (light) and phainein (to show). Phainein is also a contributing element in such words as diaphanous, emphasis, epiphany, and phenomenon, among others.