why do we see different colours when we close our eyes
Answers
As you settle into bed at night, close your eyes and begin to doze off, you may notice the colorful light show happening inside your eyelids. When you rub the sleep from your weary eyes, the lights suddenly intensify and bursts of bright colors appear all across your field of vision. A few seconds later, the colors settle down again. While you might appreciate the bedtime entertainment, in the back of your drowsy mind you’ve probably wondered what the heck you’re even seeing.
These strange blobs you see have a name; they’re called “phosphenes,” and researchers believe that actual light may play a role. But not ordinary light — this light comes from inside your eyes. In the same way that fireflies and deep-sea creatures can glow, cells within our eyes emit biophotons, or biologically produced light particles.
“We see biophotonic light inside our eyes in the same way we see photons from external light,” said István Bókkon, a Hungarian neuroscientist who works at the Vision Research Institute in Lowell, Massachusetts.
Biophotons exist in your eyes because your atoms constantly emit and absorb tiny particles of light, or photons. This photon exchange is just a part of normal cellular function. Your eyes can’t tell the difference between photons from outside light and the biophotons emitted by your own atoms. Either way, your optic nerve simply relays these light signals to the brain, which must then decide if it accurately represents the real world around you, or if it’s just a phosphene.
Our eyes actually produce far more biophotons than we end up seeing as phosphenes. “When you rub your eyes, this generates biophotons in many parts of the eyes,” explained Bókkon. “But they are mostly absorbed locally.” Almost all of the biophotons you see are the ones both emitted and absorbed by atoms in the retina — the part of your eye responsible for detecting light.
Inside the retina, millions of tiny cells called rods and cones collect light and convert it into electrical signals. These signals travel through the optic nerve to a part of the brain called the visual cortex. Here, the brain reconstructs an image using the information received from the eyes. When a reconstructed image looks like nonsense, the brain is quick to label the image as unreal, or a phosphene.
They are thought to be caused by the inherent electrical charges the retina produces even when it is in its “resting state” and not taking in a ton of information and light like it does when our eyes are open.