Science
How does vision work?
Vision works by your eyes focusing light onto a layer of light-sensitive cells, which send signals to your brain to build an image. The lens focuses incoming light onto the retina, and the brain interprets those signals as the scene you 'see.'
See it in motion.
Watch a 2-minute animated lesson that shows exactly how vision works.
Step by step
- 1Light enters through the cornea and lens, which focus it.
- 2It lands on the retina, lined with light-sensing cells (rods and cones).
- 3Those cells convert light into electrical nerve signals.
- 4The optic nerve carries the signals to the brain.
- 5The brain assembles and interprets them into the image you perceive.
Frequently asked questions
- How do eyes see color?
- Cone cells in the retina come in types sensitive to red, green, or blue light; the brain combines their signals into the full range of colors.
- Why do some people need glasses?
- If the eye focuses light slightly in front of or behind the retina, the image blurs; lenses shift the focus back onto it.
- Does the brain do part of seeing?
- Very much — the eye captures light, but the brain interprets the signals, fills gaps, and constructs what you actually perceive.