Cornea surgery, also known as keratoplasty, is a medical procedure performed to replace part or all of a damaged cornea with healthy tissue from a donor. The cornea is the transparent, dome-shaped outer layer at the very front of the eye that covers the iris and pupil. It serves two primary functions: providing a protective barrier against germs and debris, and acting as the eye’s main focusing lens, responsible for approximately two-thirds of the eye’s total refractive power.
For light to be focused onto the retina, it must pass through this clear, smooth surface. Any clouding, scarring, or shape irregularity can severely impair vision. When the cornea is damaged, the resulting blurred vision or persistent eye pain often cannot be corrected with glasses or contact lenses, signaling the need for surgical intervention.
Conditions Requiring Cornea Surgery
Diseases, injuries, and infections can cause permanent damage to the cornea, leading to the loss of its transparency or smooth shape. One common indication is Keratoconus, a progressive condition where the cornea thins and bulges outward into an irregular cone shape. This causes light rays to become distorted and vision to blur, and the irregular shape cannot be fully corrected with standard eyeglasses.
Another frequent cause is Fuchs’ dystrophy, an inherited condition affecting the innermost layer of the cornea called the endothelium. These endothelial cells work like tiny pumps to keep the cornea clear by removing fluid; when they fail, the cornea swells and becomes cloudy, especially noticeable upon waking. Severe corneal ulcers resulting from bacterial or fungal infections can also leave behind dense scar tissue that blocks light from entering the eye.
Physical trauma or injury to the eye can cause deep scarring or thinning across the corneal layers, necessitating a transplant. Complications from previous eye surgeries, such as swelling that occurs months or years after cataract removal, may also damage the cornea to the point that a transplant is required.
Explaining Major Transplant Procedures
Cornea transplant procedures have evolved significantly, moving from full-thickness replacement to targeted, partial-thickness techniques that replace only the diseased layers. All procedures rely on healthy donor corneal tissue provided by an eye bank, which is checked for health and suitability before use. The traditional method, still used for full-thickness damage, is Penetrating Keratoplasty (PKP).
PKP involves removing a circular section of the patient’s entire diseased cornea and replacing it with a full-thickness donor graft, held in place with tiny sutures. This is reserved for severe cases where all layers, including the central stroma, are compromised by scarring or advanced Keratoconus. A more selective approach for Keratoconus and other anterior scars is Deep Anterior Lamellar Keratoplasty (DALK).
DALK replaces the diseased outer and middle layers (the epithelium, Bowman’s layer, and the stroma), while intentionally preserving the patient’s own healthy innermost endothelial layer. Preserving the patient’s own tissue significantly lowers the risk of long-term graft rejection compared to a full-thickness transplant. For conditions like Fuchs’ dystrophy, where only the innermost layer is failing, Endothelial Keratoplasty is the preferred method.
This selective surgery comes in two primary forms: Descemet’s Stripping Automated Endothelial Keratoplasty (DSAEK) and Descemet’s Membrane Endothelial Keratoplasty (DMEK). DSAEK replaces the diseased endothelium and Descemet’s membrane along with a small amount of the adjacent stroma. DMEK transplants only the single, ultra-thin layer of the Descemet’s membrane and the endothelial cells. DMEK is favored for endothelial diseases because it provides faster visual recovery and the lowest risk of rejection, though it is technically more challenging than DSAEK.
Post-Surgical Recovery and Long-Term Care
Recovery varies significantly depending on the type of procedure performed. Patients who undergo partial-thickness transplants, such as DMEK or DSAEK, often see initial visual improvement within weeks, with stabilization occurring over a few months. In contrast, a full-thickness PKP requires a much longer healing period, with final vision stabilizing over 12 to 18 months, partly due to the time needed for suture removal and management of surgically induced astigmatism.
For endothelial procedures (DSAEK/DMEK), patients are instructed to lie flat on their back for a specified period in the first few days. This helps a temporary air or gas bubble hold the new, thin graft in the correct position. All patients will be prescribed a regimen of eye drops, including antibiotics and anti-inflammatory steroid drops.
The steroid drops are particularly important and must be used long-term—sometimes for years—to prevent the body’s immune system from attacking the donor tissue, known as graft rejection. Patients must avoid activities that put pressure on the eye, such as heavy lifting or strenuous exercise, for several weeks post-surgery. They should also wear a protective eye shield, especially at night, to prevent accidental rubbing or injury.
Patients must be vigilant for signs of graft rejection, which include worsening eye redness, increased pain, sudden light sensitivity, and a rapid decrease in vision. Reporting these symptoms immediately to the surgeon is necessary for prompt treatment and graft survival.