How do my eyes let me see colors and shapes?
Eye's Secret Movies
How do my eyes let me see colors and shapes?
Right now, light is bouncing off everything around you — your hands, the wall, this page — and a tiny slice of it is diving straight into your eyes. Your eyes catch that light and turn it into the whole colorful, shapely world you're looking at. Let's follow a beam of light inside and see how the trick works.
First, light has to get in. At the front of your eye is a clear, curved window called the cornea, and behind it a dark hole called the pupil — the little black circle in the middle. The pupil is really just a doorway. In bright light it shrinks to let less in; in the dark it opens wide to grab every drop it can.
