We also do transplants for perforated corneal ulcers, for cosmetic reasons, non-healing infections and other less common problems.
We rely on deceased people who have donated their organs for the corneal tissue that is used in the transplant. South Africa typically has a very low level of organ donation. We usually rely on importing corneas from the USA where people donate their organs far more freely.
There are several ways of transplanting the cornea and the most commonly performed operation in South Africa at present is a penetrating keratoplasty. In this operation the central part of the patient’s cornea is removed and a similar sized portion of the donated cornea is stitched in its place with multiple microscopic nylon sutures.This operation takes between 60 and 90 minutes and is done under general anaesthetic.
RISKS OF SURGERY
As with any operation on the eye (or any part of the body) there are risks involved.
Some complications include:
- Corneal graft rejection – just like with other organ transplants, the transplanted corneal tissue may be rejected by the patient’s body. The risk is about 10% for keratoconus and corneal dystrophies but as high as 50% for perforated ulcers.
- Infection – a risk of about 1 in 500. We prevent this as far as possible with antibiotic drops and anti-septic surgical techniques.
- Astigmatism – the transplanted tissue is seldom as regular in shape as nature intended. The irregular shape is called astigmatism and can be corrected to an extent with glasses but more definitively with hard contact lenses.
- Glaucoma – high pressure in the eye immediately after the operation.
- Other complications – retinal detachment, retinal oedema or swelling, persistent ocular surface inflammation, dry eyes, cataracts.
Serious complications usually require urgent treatment and sometimes even further surgery. The chance of having a blind eye following a serious complication is fortunately small and is less than 1 in 1000.
Corneal transplantation is not particularly painful although a scratchy, uncomfortable eye is common for several days after the operation. Analgesic pills are prescribed and can be used if needed.
Patients are usually admitted to the ward after the operation and are discharged the next day following a check-up in the consulting rooms. Eye drops are used at regular intervals and the type of drop and frequency differs from person to person. Sometimes cortisone pills are used for a few days to aid recovery.
Normally there would be further check-ups in the consulting rooms at week 1, week 3 and then 6 to 8 weeks after the surgery. There are periodic reviews up until one year when typically the stitches are removed. Sometimes loose or overly tight stitches are removed before one year.
After the stitches are removed most patients need to visit a contact lens optometrist for a hard contact lens fitment to negate the effect of post-operative astigmatism. Sometimes only glasses are needed.
WHAT IS THE OUTCOME OF A CORNEAL TRANSPLANT?
Corneal transplant surgery is not a perfect science. It is done when the problem with the patient’s eye is very serious and is done to improve an already bad situation. The aim is to get the best possible vision and this is usually only achieved with the use of a hard contact lens and at very least the use of glasses.
Good results also depend on preventing rejection and using optimal treatment from the doctor after the surgery. Graft rejections can be reversed in the early stages and may require admission to hospital for intensive treatment.
Corneal transplantation is undertaken for serious problems which profoundly affect vision. With good surgery and aftercare this procedure makes an enormous difference to a poor seeing eye. The visual recovery is very slow and it may be as long as 1 year before the final outcome can be established.