Parts of the eye

Lens
The lens is a transparent body behind the iris, the coloured part of the eye. The lens bends light rays so that they give a clear image to the back of the eye - the retina. As the lens is elastic, it will change shape, getting fatter for close objects and thinner for distant objects.

Cornea
The cornea is a transparent membrane which forms the outer coating of the eyeball. Its main purpose is protection and it is the outer-most refractive surface of the eye.

Retina
Imagine that the eye is like a camera, and the retina is the film. The retina is a fine sheet of nerve tissue lining the inside of the eye. Rays of light enter the eye and are focused on the retina by the lens. The retina produces a picture which is sent along the optic nerve for the brain to interpret. It is rather like the film in a camera being developed so that pictures can be produced.

Macula
Again, imagine that the eye is like a camera. There is a lens and an aperture (an opening) at the front, which both adjust to bring objects into focus on the retina at the back of the eye. The retina is made up of a delicate tissue that is sensitive to light, rather like the film in a camera. The macula is found at the centre of the retina where the incoming rays of light are focused. The macula is very important and is responsible for:

• What we see straight in front of us
• The vision needed for detailed activities such as reading and writing
• Our ability to appreciate colour