Model of human eye, French, c 1870.
© Science Museum / Science & Society Picture Library
Model showing the different parts that make up this complicated and sensitive organ. The eye sits inside a bony cup, called the eye socket. It is cris-crosed by tiny blood vesels that keep it supplied with oxygen. Pairs of muscles link the eye to the eye socket, and when a muscle contracts the eye swivels in its socket. At the back of the eye is the optic nerve, which takes electrical signals to the brain. At the front is the cornea, a clear protective layer, behind which is the pupil, an opening that lets in light, to fall on the retina.