The eye is composed of three layers, each of which has one or more very important components.
The Outer Layer
The outer layer contains the sclera (the white of the eye) and the cornea (the clear dome at the front of the eye). The cornea is like a window into the eye. It lies in front of the iris, the coloured part of the eye. The iris acts like the shutter of a camera, regulating the amount of light that enters the eye by changing its size, depending on brightness.
Further behind the cornea is the eye’s clear lens which helps you focus on things close up or far away. Between the lens and the cornea is clear liquid called aqueous which is constantly produced and then drained from the eye through channels called the trabecular meshwork. These drains are found at the base of the iris. The eye’s pressure, also called the intraocular pressure, or IOP, is determined by how easily fluid drains from the eye. Between the lens and retina is a jelly like material called the vitreous.
The Middle Layer
The middle layer of the eye is called the uvea. It contains vessels that carry blood through the eye to nourish it.
The Inner Layer
The inner layer of the eye, or retina, is similar to film in a camera. It receives light from an image we are looking at, and converts that light into electrical impulses which are sent through the fibres of the optic nerve to the brain.