The human eye is a light-gathering device much like a camera and without it we would not be able to see. It is incredibly intricate with many different parts, and no one is sure how all of it works. In this section we will explain its basic structure and the purpose of its various features.
The eyeball itself is roughly spherical and sits in the eye socket, also known as the orbit. The orbit is covered in fatty tissues which surround the eyeball and protect it from impacts with the wall of the orbit. We will see that the eye also has many other protection mechanisms so that it will not be injured, an indication of its importance to our body and survival. Six muscles are attached to the outside of the eyeball. These muscles can contract and move the eyeball around, allowing us to look at different places in our field of vision without moving our heads. From the back of the eyeball extends a thick cord of nervous tissue called the optic nerve. This collection of neurons (nerve cells) carries signals from the eye to the brain.