The retina is covered with specialized cells called rod cells (black and white) and cone cells (colors) they convert electrons that hit them into electrical impulses/nerve impulses that are...
We see out of the eye because of the light that's hits the eye and the light that we see it sends a signal to the brain and then we can see the picture.
they have light receptors that control that,.;... even with the use of extacy and magic mushrooms.. it ruins it and causes you to see brighter light and hallusinate