The cornea is the clear, front window of the eye. It helps focus light into the eye so that you can see. The cornea is made of layers of cells. These layers work together to protect your eye and provide clear vision.
Your cornea must be clear, smooth, and healthy for good vision. If it is scarred, swollen, or damaged, light is not focused properly into the eye. As a result, your vision is blurry or you see a glare.
If your cornea cannot be healed or repaired, a corneal transplant might be a recommended approach. This is when the diseased cornea is replaced with a clear, healthy cornea from a human donor.
There are different types of corneal transplants. In some cases, only the front and middle layers of the cornea are replaced. In others, only the inner layer is removed and sometimes the entire cornea needs to be replaced.
Full Thickness Corneal Transplant
Your entire cornea may need to be replaced if both the front and inner corneal layers are damaged. This is called penetrating keratoplasty (PK), or full thickness corneal transplant. Your disease or damaged cornea is removed. Then the clear donor is sewn in place.
PK has a longer recovery period than other corneal transplants. Getting complete vision back may take up to 1 year or longer.
Partial Thickness Corneal Transplant
At times,the front and middle layers of the cornea are damaged. In these cases, only those layers are removed. The endothelial layer, or the thin black layer, is kept in place. This transplant is called a deep anterior lamellar keratoplasty (DALK) or partial thickness corneal transplant. DALK is commonly used to treat keratoconus or bulging of the cornea.
Healing time after DALK is shorter than after a full corneal transplant. There is also less risk of rejection of the donor cornea