Cornea. The clear membrane covering the front of the iris and pupil, the function of which is to refract the light entering the eye. It makes up one sixth of the eye’s surface

Sclera. The tough, white covering of the eye, making up five sixths of its surface. It provides protection and serves as the attachment for the ocular muscles that move the eye

Conjunctiva. The mucous membrane covering the front part of the sclera and lining the inside of the eyelids. It protects and lubricates the eye

Choroid. The spongy middle layer of the eye located between the sclera and the retina. It provides oxygen and nourishment to the outer layers of the retina

Aqueous humour. A watery fluid behind the cornea that circulates in the front part of the eye and keeps the pressure inside constant

Iris. The coloured circle surrounding the pupil. It changes the size of the pupil to allow varying amounts of light into the eye

Pupil. The dark, circular hole in the centre of the iris through which light enters the eye. It gets larger in dim light and smaller in bright light

Lens. A transparent structure behind the iris that changes shape to bend light rays, focusing them onto the retina

Vitreous humour. A colourless, gel-like material filling the inside of the eye from the lens to the retina, helping keep the eye inflated

Retina. A layer of light-sensitive cells right at the back of the eye that collect and send information from light signals along the optic nerve

Macula. The small and highly sensitive bulls-eye at the centre of the retina responsible for detailed central vision

Optic nerve. Takes information from the retina to the brain

Blood vessels. Bring nutrients to the nerve cells.