825 Fishburn Road Hershey, PA 17033 | 717.533.5200
Corneal and External Disease Evaluation
Our eye doctors at Central PA Eye Institute in Hershey, PA have been trained to diagnose and
treat the spectrum of eye diseases, but also
have special expertise in the cornea. There are
many diseases that can affect the cornea. To
accurately diagnose and manage your disease, our
doctors will examine and test other structures
in the eye as well.The cornea is the transparent, dome-shaped
window covering the front of the eye. It focuses
light on the retina and determines the clarity
of the image we see. Like the front lens of a
camera, it gives us a clear window to look
through. Because there are no blood vessels in
the cornea, it is normally clear and has a shiny
surface. The cornea is extremely sensitive -
there are more nerve endings in the cornea than
anywhere else in the body.
The adult cornea is only about 1/2 millimeter thick and is comprised of 5 layers: epithelium, Bowman's membrane, stroma, Descemet's membrane and the endothelium.
The epithelium is layer of cells that cover the
surface of the cornea. It is only about 5-6 cell
layers thick and quickly regenerates when the
cornea is injured. If the injury penetrates more
deeply into the cornea, it may leave a scar.
Scars leave opaque areas, causing the corneal to
lose its clarity and luster.
Bowman's membrane lies just beneath the epithelium. Because this layer is very tough and difficult to penetrate, it protects the cornea from injury.
The stroma is the thickest layer and lies just beneath Bowman's. It is composed of tiny collagen fibrils that run parallel to each other. This special formation of the collagen fibrils gives the cornea its clarity.
Descemet's membrane lies between the stroma and the endothelium. The endothelium is just underneath Descemet's and is only one cell layer thick. This layer pumps water from the cornea, keeping it clear. If damaged or disease, these cells will not regenerate.