Colors and light are only visible to us because of our eyes (objects emit light of a particular wavelength, which enters our eyes and allows us to see colors), so thank your eyes for all the wonders of the world!
Now, it’s quite obvious that we see colors when we ‘look’ at things, but have you ever noticed that sometimes we see colors even when our eyes are closed? Why does that happen? Are you a superhero in the making or is there a scientific explanation for this phenomenon?
Phosphenes: Colors and Patterns Behind Our Eyelids
The colors that you see are not necessarily present in the external world, but it really is the inside of your eyes that is making you see those blobs and patterns of color. These visible spots on the back of your eyelids are collectively called phosphenes. One very common myth pertaining to our eyes is that they are only activated when they receive some external stimulus (light from the outside). However, the truth is that the neurons working in the vision system are always active.
Even with our eyes closed, there is a certain amount of neurological activity occurring inside our eyes, which means that there is random firing of neurons happening. It should be noted that this happens all the time, whether your eyes are shut or not. It’s just that when your eyes are open, the visual information that you take in through your eyes easily ‘crowds out’ the minute and random motions of neurons within the visual system.
However, in the absence of any visual information from the outside, you are able to see these random colors and patterns.
When Do We See Colors Behind our Eyelids?
Generally, one experiences a visual image of these phosphenes right after rubbing one’s eyes. It happens because the pressure applied due to rubbing the eyes, as this produces a lot of biophotons in the retina of the eyes. Most of these biophotons are absorbed by the retina itself, which converts this visual information to electrical signals through the use of rods and cones before sending it back to the brain (the visual cortex).
As soon as the brain formulates an image of the visual information sent by the retina, it determines that it is total rubbish. Consequently, you random colors, blobs and grids rather than definite shapes.
There are other (and not so popular) methods of seeing phosphenes, such as being hit on the head or face, standing up too fast, or as the result of a particularly hard sneeze.
So, if you see stars after being punched in the face, know that you’re supposed to.