Anatomy of a normal eye
The cornea forms the clear window into the eye.
The iris, which is the coloured part of the eye with the black pupil in the middle, is behind the cornea.
The lens lies behind the iris. In a healthy eye the lens is clear and able to focus light on to the retina, the light-sensitive nerve layer that lines the inside of the eye. Rays of light enter the eye, passing through the cornea, pupil and lens before focusing on to the retina. The retina contains photoreceptors which convert light into electrical impulses. In the healthy eye these impulses are sent via the optic nerve to the brain where sight is interpreted as clear, bright, colourful images. The retina can be likened to photographic film in a camera.
||In a healthy eye the lens is clear and able to focus light on to the retina, the light-sensitive nerve layer that lines the inside of the eye.
The wall of the eye is formed of three layers, the retina, choroid and sclera. The choroid is the underlying vascular (blood vessel) layer of the eye from which the retina receives oxygen and nutrients. The sclera or “white of the eye” forms a tough protective coat.
The macula is a small area at the centre of the retina. It is very important as it is responsible for our central vision. It allows us to see fine detail for activities such as reading, recognising faces, watching television, and driving. It also enables us to see colour.
The vitreous is the clear, jelly-like substance which fills the hollow space behind the lens.