In simple terms, the Cornea is the windshield of the eye. Normally, it is a clear and transparent layer on the front of the eye which protects the eye content and helps focus light on the retina to allow us to see. It is composed of 3 cellular levels – epithelium, stroma, and endothelium. All 3 layers must remain, smooth, translucent, and healthy for the cornea to function properly.
The epithelial layer acts as the “skin” of the eye. This very superficial layer covers the very surface of the eye and regenerates every 5-7 days much like the rest of the skin. The layer must remain smooth, lubricated with tears, and well-attached to the cornea to function properly. Trauma to this area will create a “corneal abrasion” which is analogous to scraping one’s knee and is quite painful. They layer can also become irregular and causes pain or blurry vision in conditions such as dry eye, epithelial basement membrane dystrophy, or pterygium.
The stroma is the structural component of the cornea composed of evenly layered collagen molecules making up approximately 90% of the corneal thickness. This layer must remain clear and even for light to travel through it. Conditions such as keratoconus, infections, or trauma distort the shape of the stroma and induce permanent scarring. This prevents the light from traveling in straight lines and causes blurry vision.
The endothelium is the innermost layer of the cornea and is composed to “pump” cells. Since the eye is constantly bathed in tears, the pumps are necessary to absorb any extra moisture. If the pump function decreases, the cornea because overly hydrated. The swollen cornea becomes cloudy with a bluish hue and creates a constant perception of looking through fog. In severe cases, blisters form on the cornea surface from fluid overload and can become quite painful.
Cornea surgeons are experts in all structures on the front of the eye including the cornea, iris, and cataracts. A cornea surgeon is a board-certified ophthalmologist who has completed further fellowship training in Cornea and Refractive surgery. This field of medicine is devoted to treating problems of the front of the eye such as refractive error, cornea opacity, cataracts, and dry eye.
As ophthalmologists, we understand that keep the cornea and lens smooth and clear is integral to maintaining great vision. Obstruction from a cornea scar, corneal edema, dislocated lens or cataract can preclude the light from reaching the retina in an even fashion resulting in blurry vision. In those instances, a cornea surgeon can help by correcting the anatomic deformity. Corneal transplant and cataract surgery are two of the most common procedures performed by a cornea surgeon. LASIK, removal of pterygiums or ocular surface cancer, minimally invasive glaucoma surgery, lens exchanges, and iris defect repair are also very commonly performed by a cornea surgeon.