A doctor can recommend corneal transplantation only after a careful examination of the eye. The most common reasons
for performing the operation are:

• Injury to the eye — affecting cornea badly. This will affect the vision and thus a doctor after careful review and
  examination will advise for transplant.
• Medical conditions — Corneal damage caused by some infections or other medical conditions
• Pseudophakic bullous keratopathy — some people experience corneal swelling and clouding after cataract surgery.This is known as pseudophakic bullous keratopathy and is a common reason for corneal transplantation
• Keratoconus — sometimes the cornea is thin and weak, and the normal pressure inside the eye makes the cornea bulge outward in a cone shape. This is called Keratoconus, and it causes severe vision problems. If these problems are very troublesome, the doctor might recommend a corneal transplant

Corneal transplantation can be done under general anesthesia; that is, with the patient “asleep.” Local anesthetic, in which the patient is awake but does not feel the procedure, also can be used.

A portion of the cornea is removed using scissors and a special instrument called a trephine, which works something like a tiny circular cookie-cutter. This leaves an opening in the patient’s cornea.

A similarly sized trephine is used to cut a section from the donor cornea. This section of corneal tissue is placed into the opening in the patient’s cornea and fastened with very small stitches. Many patients qualify for a partial-thickness corneal transplant procedure called DSAEK (Descemet’s stripping with automated endothelial keratoplasty) tailored to particular corneal disorders. This procedure can provide faster recovery with less visual distortion.

After surgery, it is important not to put any pressure on the eye. It is best not even to touch or rub anywhere near the eye,so the doctor might put a shield over it. Wearing glasses or sunglasses will also help protect the eye.

Your doctor will prescribe eye drops to help the eye heal and prevent infection. It is necessary to keep using some of these medications for several months after a corneal transplant. Without these medications, the eye is much more likely to have problems with the new corneal tissue.

How successful is corneal transplantation?

The majority of the corneal transplantations done in patients with keratoconus, corneal scars and most types of corneal disease are successful. The operation is less successful in eyes with a corneal infection or severe injury such as a chemical burn.