The Cornea Blog
The cornea is the clear outer window to the back of the eye. Why is it important to understand what the cornea is and how it works? The answer is that because if any part of the cornea is compromised, no matter how healthy the rest of the eye is, you will not be able to see as well as you should be able to.
The cornea is composed of three main layers. The epithelium is the top layer of the cornea. Many patients with dry eyes can attest to the fact that if the corneal surface does not have adequate lubrication, symptoms can vary from burning and excess tearing to extremely variable vision. Contact lens over wear can also cause erosions in the surface layer of the cornea that make lens wear uncomfortable or impossible. Corneal abrasions often only affect the epithelium. This can be extremely painful but the epithelium can normally heal itself within 24-48 hours.
The middle layer of the cornea is called the stroma. This is the thickest layer of the cornea. If the stroma is compromised, significant vision loss can occur. Corneal infections that are not treated can damage this important layer. It is important to know that a corneal scar can only be obtained if the stroma is sufficiently damaged. This can happen with a foreign body such as a piece of metal in the eye, a severe infection that does not get properly treated or a corneal abrasion that goes deeper than the superficial epithelium.
The innermost layer of the cornea is called the endothelium. This layer is important because it serves to pump fluid out of the stroma. Many people have corneal dystrophies or bilateral disorders that cause this layer of the cornea to not function properly. If excess fluid enters the cornea and causes swelling, visual acuity is compromised. In extreme cases, a cornea transplant is required to replace the diseased corneal layers with healthy tissue.
It is very important to take care of your eyes and the cornea is our first line of defense. Please remember to wear protective eyewear in the form of safety glasses, sports goggles and sunglasses to make sure that your cornea is protected!