1. Seeing is when light goes into your eye. It passes the colored part (the iris) and a little glassy part (the lens) and makes an upside-down picture at the back of the eye (the retina). Tiny wires (nerves) send that picture to your brain, and your brain turns it the right way so you know what you are looking at.
2. Light comes into the eye and goes through the iris and lens. The back of the eye gets a flipped picture. The nerves carry that flipped picture to the brain, and the brain flips it back so you see things the right way up.
3. Our eyes let light in through the colored circle and a small lens. That light makes an upside-down photo on the retina at the back. Then signals travel along tiny nerves to the brain, and the brain makes the photo normal again so you can understand it.
4. To see, light enters the eye through the iris and lens and hits the retina at the back, making a picture that is upside down. The eye's nerves send the picture to the brain, and the brain fixes the picture so you see everything the right way.