A normal eye is shaped like a ball.
The cornea is a transparent structure found in the very front of the eye that helps to focus incoming light. Situated behind the pupil is a colorless, transparent structure called the crystalline lens which focuses the light on the retina at the back of the eye. The retina is the delicate innermost layer of tissue that lines the eye. It contains layers of light receiving cells called photoreceptors that are connected to the brain by the optic nerve.
If you think of the eye as a camera, the retina is the film on which images are recorded and the macula is the small, central part of the retina. The macula is very important and is responsible for what we see straight in front of us. It allows us to see fine detail for activities such as reading and writing, as well as giving us our ability to see colour.