This is the white of the eye – the tough opaque outer coating. Six tiny muscles are connected to it, which control the eyes movement.
The Cornea is the transparent coating which covers the Iris and the Pupil at the front of the eye. The Cornea together with the Lens, helps refract the light and allows the eye to focus.
The Iris is the coloured part of the eye. Tiny muscles inside the Iris control the amount of light which can enter the eye by opening and closing the pupil.
Light enters the eye through the pupil. The size of the pupil is controlled by the Iris. When it is very bright and there is lots of light, the pupil is small. When it is dark, the pupil grows bigger to allow more light into the eye.
The purpose of the Lens is to focus light onto the retina at the back of the eye. Until we reach our mid 40s, the lens is able to alter shape, enabling the eye to focus on nearer objects.
The Retina contains millions of photoreceptors (sensors which convert light into electric impulses which are sent along the optic nerve to the brain). There are two types of photoreceptors – Rods (which allow us to see in low light) and Cones (which allow us to see colour and work best in brighter light).
The Optic Nerve send signals representing colour from the eye to the brain, which then interprets what we see. Where the Optic Nerve leaves the retina there are no sensory receptor cells, meaning we have a blind spot in our eye.