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About the eye

Sclera The ‘white’ of the eye that protects the eyeball and gives it its firm, regular shape.

Pupil - The black hole at the centre of the eye that allows light through.

Iris - The coloured part of the eye that controls the amount of light passing through the pupil.

Cornea - A transparent dome that protects the iris and pupil. Together with the lens, the cornea bends (refracts) light to focus it onto the back of the eye.

Crystalline lens A transparent disc that sits behind the iris.

Retina The back of the eye that contains millions of photoreceptors (sensors that convert light into electric impulses.) These signals are sent along the optic nerve to the brain, where they are processed to create an image.

Macula A small spot near the middle of the retina that is responsible for central vision.

Vitreous humorA jelly-like substance that fills the middle of the eye, giving it form and shape.

Optic nerve The nerve at the back of the eye that carries signals from the retina to the brain.

Conjunctiva A thin membrane that gives the eye protection and helps keep it moist. It lines the inside of the eyelid and the surface of the eyeball.

Aqueous humour A clear fluid that lies in the space between the iris and the cornea. This maintains eye pressure and gives the front of the eye its rounded shape.