The human eye is an amazing feat of engineering, but its component parts can seem quite mysterious. If you can’t tell your retina from your cornea, this diagram explains how our eyes allow us to view the world...
1. Vitreous humour - A clear jelly-like substance that fills the back two-thirds of the eye and allows light to pass through without interference.
2. Conjunctiva - A moist protective membrane found on the inner eyelids and the outer eyeball that contains infection-fighting properties.
3. Iris - The coloured part of the eye, which contains the muscles that adjust the pupil size, controlling how much light reaches the back of the eye.
4. Pupil - Light is channelled through the iris’s central aperture, known as the pupil, and characterised by its black appearance.
5. Lens - Tucked behind the pupil, the lens focuses on close or distant images before directing light towards the retina.
6. Cornea - This clear part of the frontal eye protects the iris and pupil, and has a distinct semi-circular shape when viewed side-on.
7. Sclera - Visible as the white part of the eye, this is the eyeball’s supportive and protective outer wall.
8. Retina - Like the film in a camera, the back of the eye is a light-sensitive membrane designed to translate images into electronic signals. Colours are processed by cone-shaped photoreceptors, while their rod-shaped counterparts handle night vision and movement.
9. Optic nerve - The retina’s electronic signals are dispatched along the optic nerve to the brain’s visual cortices.