ANATOMY OF THE HUMAN EYE

The eye can be thought of as three spheres, one within the other. The protective outer layer of the eye includes the Sclera and the clear Cornea at the front of the eye. The middle layer of the eye is the vascular layer which nourishes the eye; it consists of the Choroid, the Ciliary Body, and the Iris. The ciliary body has the dual function of altering the focus of the lens and making aqueous humor (see below). The innermost layer of the eye consists of the Neural Retina which covers the entire inside of the eye with the exception of ciliary body and the iris. The retina ends at the Ora Serrata. The Pupil is the central opening in the iris and controls the amount of light which enters the back of the eye. The Anterior Chamber is the space between the cornea and the iris and is filled with a clear fluid called Aqueous Humor. The Lens is held in position behind the iris by the Zonular Fibers. The lens focuses light on the Neural Retina (or simply the Retina) at the back wall of the eye. Nerve fibers from the retina travel along the Optic Nerve to the brain. The Vitreous Body (also called the Vitreous Gel) is a clear gel which fills the relatively large space between the lens and the retina.

The Macula is the central portion of the retina. The macula has specialized cells (cones) which are responsible for color vision and for sharp, reading vision.

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