Model of the Eye

Familiarize yourself with the three layers of the eyeball and its contents.

1. The layers of the eye
   The external layer consists of the sclera and cornea; the middle layer (vascular layer) consists of the choroid, ciliary body and iris. The inner layer is nerve tissue, the retina. The retina consists of an outer pigment epithelium and an inner retina proper.
2. The contents of the eye
   The lens is a biconcave transparent disc, held in place by the zonule, a circular system of fibers that extends from the lens capsule to a thickening of the middle layer, the ciliary body. An expansion of the middle layer, the iris, extends anteriorly and partially covers the lens. The round hole in the middle of the iris is the pupil.
   There are three regions within the cavity of the eyeball.
   Between the cornea and the lens is the anterior chamber (in life filled with aqueous humor).
   The posterior chamber is bounded by the iris, the lens, the zonule and the ciliary processes.
   Posterior to the lens is the vitreous space (in life filled with the vitreous body).