Corneal Functioning

Your cornea is a clear, dome-shaped surface covering the front of your eye. Unlike other bodily tissues, the cornea does not have any blood vessels to protect it from infection. Instead, it relies on tears and the aqueous humor in your eye for nourishment and protection.

There are five layers of the cornea. All play a major role in its proper functioning. The epithelium is the outer layer of the cornea, and accounts for approximately 10% of its thickness. Its purpose is to block the entrance of substances such as dust, bacteria, or water into the rest of the cornea and other parts of your eye, and to absorb nutrients from tears and oxygen. This layer is very sensitive to abrasions.

The Bowman's layer is beneath the epithelium, and is made up primarily of collagen. Damage to Bowman's layer can cause scarring which may contribute to vision loss. The Stroma is the next layer, and accounts for almost 90% of your cornea's thickness. It provides your cornea with its strength, elasticity, and form, and it is integral in your cornea's light-conducing abilities.

The Descemet's membrane lies below the Stroma. It is a thin tissue providing your eye protection from infection and damage. The endothelium is the inner layer of your cornea. Its purpose is to conduct excess fluid out of the Stroma. If these cells are destroyed, they cannot be replaced. Endothelium damage can lead to blindness, and a corneal transplant is the only way to correct the problem.

Your cornea is responsible for transmitting the light that will be focused by your retina. If your cornea is shaped irregularly, images will not focus properly on your retina. This leads to many of the most common vision disorders, such as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism.

LASIK surgery can help correct corneal irregularities to improve your vision. The procedure uses an excimer laser to reshape your cornea, enabling images to focus properly on your retina. In order to be a candidate for LASIK, your cornea must meet minimum levels of thickness. Your ophthalmologist will conduct a thorough eye exam to make sure that you are an ideal candidate.

You can use the links at the bottom of this page to find a qualified LASIK surgeon in your area.