New surgery tackles severe cornea diseases

Liyana Low
The plastic implant successfully sewn into the patient's eye. (Courtesy of SMG)

An acid attack on her face when she was in her mid-teens left Grace (not her real name) blind in both eyes. After four cornea transplants in her left eye, she was still having difficulty seeing because she developed an infection after each transplant.

This August, however, the 20-something-year-old from China has new hopes of permanent and clear vision after undergoing a new procedure targeted at patients with severely damaged corneas.

The procedure known as Boston Keratoprosthesis (Boston Kpro) -- or artificial cornea transplant -- replaces the damaged cornea with an artificial cornea, which is a hard round piece of plastic the size of a 5-cent coin supported by a cornea graft. The artificial cornea has a 3mm opening that acts as a "clear window" for the patient to see again.

It is used in cases when the patient has had a failed cornea transplant or when the patient has a very severely damaged cornea. A normal cornea transplant is usually sufficient for less severe cases.

Founded in the U.S., the four-hour surgical procedure was first conducted in Singapore by eye surgeon Leonard Ang in 2008. According to Ang, medical director of The Eye and Cornea Transplant Centre and the only surgeon who has done the procedure in Southeast Asia, Boston Kpro is different from the normal cornea transplant that many patients go through.

During a normal cornea transplant, a donated cornea replaces the damaged one but the patient will then be reliant on immunosuppressant drugs to reduce the risk of their bodies rejecting the donated cornea. The Boston Kpro implant, on the other hand, is made up of bio-compatible plastic material and thus eliminates the need for immnosuppressants.

The implant has a worldwide retention rate -- where the body does not reject the implant -- of 95 per cent. In a normal cornea transplant, there is a 10 to 20 per cent chance that the body will reject the donated cornea within five years. If a patient has had a failed transplant, the chances of rejection increases to more than 50 per cent the next time a cornea transplant is performed.

Recovery is also faster with Boston Kpro
. Normal cornea transplant patients usually take six to nine months to regain their sight while seven of the eight patients Ang has treated in Singapore have achieved vision that is fit for driving two months after the surgery.

Post-operative care for both surgeries are similar. The patient will also need to go for regular check-ups every four to six months and will have to use at least two types of eye drops daily to prevent infection and inflammation.

Unlike a normal transplant that costs about $10,000 to $15,000, the Boston K-pro surgery could set a patient back by $30,000 to $35,000.

Potential complications with this new method include an increase in eye pressure, infection, inflammation and a membrane forming behind the implant.

About 4,000 Boston Kpro surgeries have been performed worldwide, mainly in the U.S. and Europe.