What is a Corneal Transplant?
The cornea is the transparent skin tissue covering the iris and pupil. Besides being the perfect place to park your contact lenses, the cornea is also responsible for most of the eye’s light bending ability which focuses a clear image into the eye.
In patients with a diseased cornea, it may no longer be transparent resulting in blurred or obstructed vision which may not be correctable with glasses or contact lenses. If this is the case, a corneal transplant may be the only way to improve vision and help patients who may be significantly visually impaired.
There are many conditions that may result in the need for a corneal transplant. Most of these conditions involve scarring of the cornea in which non-transparent tissues form in the diseased cornea causing a blurred image. Scarring can be a result of eye diseases such as keratoconus (link) and other inherited corneal disorders. It can also be the result of corneal abrasions, infection and ulceration, or penetrating injuries to the eye. Refractive surgery procedures such as LASIK can (rarely) thin the cornea to the point of instability and poor vision, requiring a corneal transplant.
Corneal transplantation is a complicated surgery requiring months of recovery during which the vision is often quite blurry. Eye doctors usually try all means necessary to avoid a corneal transplant and surgeons will perform the procedure only when the vision is very poor and not correctable by glasses or contact lenses.
Delicate suturing of corneal transplant
During the surgery, the damaged central cornea is removed and a donor cornea is carefully stitched into place. This is a very delicate procedure requiring a skilled surgeon. The cornea is a unique tissue as it has no blood vessels but rather gets all of its oxygen directly from the air. Without blood vessels bringing in immune system battle troupes, chances of rejection are reduced but sometimes the immune system will recognize the corneal transplant as being foreign tissue. This can result in tissue rejection and the need to repeat the transplant years or decades later.
After the surgery and healing period, corrective lenses are almost always needed to maximize visual potential. Unfortunately, glasses or soft contact lenses rarely provide good vision after a corneal transplant as the prescription is usually very irregular and variable. Scleral contact lenses are usually the lens of choice for post transplant vision corrections. I have personally fit many patients in scleral lenses after a corneal transplant with some very nice outcomes allowing patients to return to their normal activities after many years of blurry vision. Very rewarding work!
Fortunately for some types of inherited corneal disorders such as keratoconus, corneal crosslinking can be used to strengthen the weak cornea before scarring occurs and transplant is needed. In some cases, where only the inner most layer of the cornea is diseased, surgeons can perform a transplant of only that layer making the surgery far less invasive than the traditional “full thickness” transplant previously discussed.
If you or someone you know has questions about corneal transplants, please don’t hesitate to call!
Thanks for reading!
Dr. Steve