How the eye works (in brief)
Sight is our most important means of relating to the world about us. Images we see create nerve impulses that are transmitted by the eyes, and decoded by the brain to provide us with our precious vision.
The eyeball and its lens focus light from an image onto the retina. The amount of light entering the eye is controlled by the pupil, which opens and closes. The light sensitive cells on the retina detect the electrical impulses and they travel to the brain. Although the image is inverted when received, the brain automatically produces it upright.