Corneal Anatomy
In order to understand how corneal surgery can help treat corneal disease and refractive error, it is helpful to review the important parts of the corneal anatomy.
The cornea, which is about the thickness of a credit card, is comprised of several layers of tissue. The surface of the cornea is covered by a very thin layer of skin cells called the epithelium, which rests on a fine collagen membrane called Bowman’s membrane. The bulk of the cornea, which lies underneath the epithelium and Bowman’s membrane, is called the stroma. Underneath the stroma lies Descemet’s membrane, this separates the stroma from the innermost lining of the cornea. The innermost portion of the cornea is a thin layer of cells called the endothelium, which is responsible for keeping the fluid inside the eye out of the cornea.
The cornea plays an important role in focusing light that enters the eye. When light passes through the cornea from the outside, it is bent, or refracted, as if passing through a lens. In fact, the cornea works in concert with the crystalline lens inside to help focus light on the retina, much like the lens system of a camera.
