The corneal epithelium is the outermost layer of the cornea and is responsible for providing protection against injury and infection. The surface of the epithelium is very smooth and provides support for the tear film, which is the first refractive component of the eye. A corneal abrasion is a minor but very painful eye injury. When an abrasion occurs, the corneal epithelium is disrupted exposing underlying corneal nerves. However, the epithelial layer can heal in only a few hours making it one of the fastest healing parts of the body.
Under the epithelium is Bowman’s Layer, which is the biological glue that holds and supports the epithelium. This layer is composed of strong collagen fibers and helps to provide structural support for the shape of the cornea. Any injury that penetrates deeper than Bowman’s layer will typically produce a scar or opacity in the cornea.
The corneal stroma makes up about 90% of the thickness of the cornea. The stroma is made up of collagen fibers and contains keratocytes, cells than can aid in healing after injury or infection. Corneal collagen fibers are precisely aligned to maintain corneal clarity.
Descemet’s membrane is a thin acellular layer that supports the underlying endothelium. The endothelium is a very important layer of cells that is responsible for pulling fluid out of the cornea and maintaining corneal clarity