Book of the Ten Treatises of the Eye the sclera, a thick, hard membrane which protects the inner parts of the nerves from injury. The chorioid, a thin and soft structure filled with veins and arteries, follows next and provides nourishment to the overall structure. Finally, the retina transmits nutrients to the lenses themselves. Hunayn then presents the system responsible for protecting the eye. From the outermost level, these are the conjunctiva, cornea, and uvea. While both the conjuctiva and cornea provide protection with minimizing hindrance to the lenses, the uvea has an extra function of concentrating the pneuma exiting out of the eye to prevent it from
Retinal pigment epithelium The RPE is composed of a single layer of hexagonal cells that are densely packed with pigment granules. At the ora serrata, the RPE continues as a membrane passing over the ciliary body and continuing as the back surface of the iris. This generates the fibers of the dilator. Directly beneath this epithelium is the neuroepithelium (i.e., rods and cones) passes jointly with the RPE. Both, combined, are understood to be the ciliary epithelium of the embryo. The front end continuation of the retina is the posterior iris epithelium, which takes on pigment when it enters the iris. When viewed