A corneal transplant is an effective means of restoring vision to those blind from corneal diseases such as corneal injuries, infections and age-related corneal degenerations.

The SNEC Corneal Transplantation Program is a successful transplantation program in Singapore, by virtue of the close collaboration with the Singapore Eye Bank which is instrumental in securing a large number of high quality donor corneas each year for transplants. Each year, over 150 transplants are performed in this program, with an overall transplant survival rate exceeding 90%.

New technologies introduced include human amniotic membrane transplantation and the development of the Artificial Cornea including the latest Osteo-odontal keratoprosthesis Surgery (OOKP).

Common questions on Transplantation:

1. What is a Corneal Transplant?
2. Who will need Corneal Transplant?
3. How is Corneal Transplant performed?
4. Where does the cornea come from and how long does it take to get one? Is there a waiting list in Singapore, and can non-Singaporeans get corneas from the Singapore Eye Bank?
5. What is the chance of success and what are the risks of Surgery?

1. What is a Corneal Transplant?

A corneal transplant involves replacing a diseased or scarred cornea with a donor cornea. When the cornea becomes cloudy, light cannot pass through to reach the light-sensitive retina leading to poor vision or blindness.

Back to top

2. Who will need Corneal Transplant?

Most individuals with poor vision due to a diseased or cloudy cornea, whose nerve and retina in the back of the eye is still healthy, may benefit from a corneal transplant to see well. A cloudy or opaque cornea can occur from scarring from any cause (e.g. injuries or infections) or cloudy swelling of the cornea due to damage or ageing of the innermost layer of cells of the cornea (known as the corneal endothelial layer). This layer is not able to “grow back” or regenerate and can only be replaced by a donor cornea through transplantation.

Less commonly, corneal transplants can be done on an urgent basis to treat severe infections of the cornea, or to repair or “patch up” severe thinning, defects or perforations in the cornea or sclera (the sclera is the white coating of the eye). The latter may occur due to previous injury, inflammation or infections.

Unlike other forms of organ transplantation, corneal transplantation may be performed repeated several times if previous transplants have failed. However, the success rate of repeat transplants may be lower than a first time graft and often anti-rejection tablets may be useful in preventing problems of rejection in these cases.

Back to top

3. How is Corneal Transplant performed?

This is a microsurgical operation performed by a trained corneal transplant eye surgeon in which donated healthy corneal tissue is used to replace a diseased cornea to restore vision and eye health. The operation first involves removing the central 7 to 8mm portion of the damaged or cloudy cornea (the cornea is the clear translucent from window of the eye and measures about 12 mm in diameter). A clear and healthy donor cornea is then placed, and sutured in place with very fine microsurgical nylon sutures. This procedure is also known as a Penetrating Keratoplasty (PK).

There are several variations of this operation which exist. Sometimes, a cataract is also removed at the time of corneal transplantation, and an intraocular lens is placed to allow for good vision.

In certain instances, when the cornea is not diseased through its whole thickness, only the diseased portion (either the front portion, or the back portion) is partially dissected away, and a partial thickness donor cornea is placed. This is known as a Lamellar Keratoplasty (LK), because the cornea is essentially separated apart in layers or lamellae. The advantage here is that we only remove the diseased layers and preserve the healthy normal layers of the cornea, and in the more common form of LK, in which the anterior or front layers are diseased, preservation of the deeper or innermost layers of the cornea greatly reduces the risk of cornea graft rejection which is an important cause of graft failure in corneal transplants. This operation, however, is technically more difficult and challenging to perform, and currently, about 15-20% of corneal transplants at our centre are performed this way. SNEC today is one of the leading transplant centres in the world which offers new advanced lamellar keratoplasty techniques to corneal transplant patients.

Back to top

4. Where does the cornea come from and how long does it take to get one? Is there a waiting list in Singapore, and can non-Singaporeans get corneas from the Singapore Eye Bank?

All corneas transplanted at our centre are of excellent quality and procured by the Singapore Eye Bank (SEB). SEB gets corneas from local donors in Singapore, as well as from internationally accredited eye banks from the United States of America. Because the Singapore Eye Bank is very successful in procuring corneal tissue today, one usually has to only wait one or two weeks to receive a cornea. SEB also provides corneas for non-Singaporeans undergoing corneal transplants in Singapore.

Back to top

5. What is the chance of success and what are the risks of Surgery?

The success rate for the usual routine uncomplicated transplant is about 90% in the first year. The more common complications include increased eye pressure which can cause damage to the eye nerve (glaucoma) and cornea graft rejection. The first year after a transplant is the most crucial, because most complications, if they occur, will occur within the first year of the transplant.

Back to top