The eye is made up of three parts.

• The cornea and lens focuses light on the front of the eye.
• The retina is a light-focusing film at the back of the eye.
• The optic nerve connects each eye to the brain.

Image courtesy of the National Eye Institute, National Institutes of Health

Cornea: the transparent outer portion of the eyeball that transmits light to the retina.

Fovea: a tiny spot located in the macula that is responsible for the clearest vision on the retina.

Iris: the coloured, circular part of the eye in front of the lens.

Lens: located in the middle of the eye behind the pupil, the lens brings rays of light into focus on the retina.

Macula: a small area of the retina at the back of the eye, which is responsible for central, most acute vision.

Optic Nerve: carries messages from the retina to the brain.

Pupil: opening at the centre of the iris that controls the amount of light into the eye.

Retina: the inner layer of the eye containing light-sensitive cells that connect with the brain through the optic nerve. It also contains retinal blood vessels which feed the retina and which can be affected by diabetes.

Vitreous Body: a colourless mass of soft, gelatin-like material that fills the eyeball behind the lens.

How your eye works

The front skin on your eye is called the cornea. Its job is to focus light onto the front of the eye. The light passes through your pupil. The iris, the coloured part of your eye, is a round muscle that surrounds the pupil. The lens focuses the light to the back of your eye, called the retina. Tiny light-sensitive photoreceptors at the back of the eye send signals down fine wires to the brain. The wires joining each eye to the brain are known as the optic nerves.