Corneal Transplant Surgery
The cornea is the normally clear, front window of the eye that covers the colored iris and round, dark pupil. Light is focused while passing through the cornea, allowing us to see.
A healthy, clear cornea is necessary for good vision. If your cornea is injured or affected by disease, it may become swollen or scarred, and its smoothness and clarity may be lost. Scars, swelling or an irregular shape can cause the cornea to scatter or distort light, resulting in glare or blurry vision.
If a cornea transplant is necessary, the damaged or unhealthy cornea tissue is removed and clear donor cornea tissue is put in its place.
When is Cornea Transplant Necessary?
There are many conditions that can affect the clarity of the entire cornea. For instance, trauma or injury to the cornea can cause scarring, as can infections (especially herpes keratitis). A hereditary condition called Fuchs’ dystrophy causes corneal failure. Keratoconus causes a steep curving of the cornea. Sometimes corneal failure can occur after an eye surgery such as cataract surgery.
A corneal transplant is needed if vision cannot be corrected satisfactorily with eyeglasses or contact lenses, or if painful swelling cannot be relieved by medications or special contact lenses.
Corneal Transplant Surgery Options
A corneal transplant is done using a human donor cornea. Before a cornea is released for transplant, tests are done for viruses that cause hepatitis, AIDS and other potentially infectious diseases. The cornea is also checked for clarity.
With traditional full corneal transplant surgery (known as penetrating keratoplasty), a circular portion is removed from the center of the diseased cornea. A matching circular area is removed from the center of a healthy, clear donor cornea, placed into position and sutured into place.
With an EK cornea transplant procedure (endothelial keratoplasty), only the abnormal inner lining of the cornea is removed. A thin disc of donor tissue containing the healthy endothelial cell layer is placed on the back surface of the cornea. An air bubble pushes the endothelial cell layer into place until it heals in an appropriate position.
With a lamellar corneal transplant procedure, the superficial layers of the cornea are removed and replaced with donor tissue. Sutures are used to secure the new tissue into place.