The human eye is a remarkable optical instrument. Light enters through the cornea, passes through the pupil — whose size is regulated by the iris — and is focused by the lens onto the retina at the back of the eye.
The retina converts light into electrical signals that travel along the optic nerve to the brain, where they are interpreted as the images we see. Every structure, from the vitreous body that fills the eye to the macula that gives us sharp central vision, plays a precise role in this process.
Key facts
- The cornea provides roughly two-thirds of the eye's focusing power.
- The macula is responsible for sharp, central, detailed vision.
- The optic nerve carries over one million nerve fibres to the brain.
- The eye can distinguish approximately 10 million different colours.
Parts of the eye
- Optic Nerve
- The nerve that transmits visual information from the retina to the brain.
- Retina
- The light-sensitive layer of tissue at the back of the eye that converts light into neural signals.
- Iris
- The coloured part of the eye that controls the size of the pupil and the amount of light entering the eye.
- Pupil
- The opening at the centre of the iris through which light enters the eye.
- Cornea
- The clear, dome-shaped front surface of the eye that provides most of its focusing power.
- Lens
- The transparent structure inside the eye that fine-tunes focus for near and distant objects.
- Vitreous body
- The clear gel that fills the space between the lens and the retina, maintaining the eye's shape.
- Macula
- The small central area of the retina responsible for sharp, detailed central vision.
