How the eye works

When light passes through the cornea and the iris it is focused through the lens onto the retina. An image is received in this way and sent via the optic nerve to the brain for processing.

Normal eye: Iris, Cornea, Light Rays, Lens Retina

Cornea	The cornea is the first point for light to enter the eye. Due to the transparent nature of the corneal tissue, rays of light are allowed to pass through and be focused or “bent” toward the lens.

Iris	The iris is the coloured part of the eye. It contracts (constricts) or expands (dilates) to allow less or more light into the eye. The opening created by the Iris is called the pupil.

Lens	The lens focuses the light (which has already passed through the cornea and the iris/pupil) onto the retina.

Retina	The retina is right at the back of the eye. It is made up of various layers of cells which are highly sensitive to light. These cells react to the light focused by the cornea and the lens on the retina and send information via the optic nerve to the brain, where it is interpreted and converted to the visualised image.