A closer look
Rubbing your closed eyes vigorously causes you to see vibrant bursts of colors and geometric light patterns called phosphenes, entirely because your retinal ganglion cells cannot tell the difference between actual light and physical pressure. By mashing your knuckles into your delicate optical organs, you are mechanically triggering the nerves to fire off confused signals to the brain, producing a cheap, localized light show inside your own skull. It is basically the biological equivalent of vigorously smacking the side of an old television set to make the static change colors, proving our sensory pathways are surprisingly easy to hack with blunt force trauma. We all just naturally discovered as bored children that if we aggressively squish our eyeballs deep into our eye sockets, we can briefly hallucinate a beautiful cosmic kaleidoscope for absolutely free!
