SINGAPORE-For people whose vision has been severely affected by a damaged or diseased cornea, a transplant can offer a chance to see clearly again.
But there is a major obstacle: There simply are not enough donor corneas to meet the global need.
Globally, only about one in every 70 patients who needs a corneal transplant receives one, with the shortage particularly severe in Asia, according to Prof. Marcus Ang Han Nian, Head and Senior Consultant of the Cornea and External Eye Disease Department at the Singapore National Eye Centre (SNEC).
The scarcity has prompted SNEC to explore ways of not only improving the outcomes of corneal transplantation but also making better use of every donor tissue available.
One of the most promising developments is the possibility of using one donor cornea for two patients.
‘Selective transplantation creates the possibility of dividing one donor cornea between two patients,’ Ang said in his presentation during the SingHealth Urology and Ophthalmology Media Immersion held in July, which brought together journalists from the Philippines, Malaysia, Indonesia and Vietnam.
Under the approach, the outer layer of a suitable donor cornea can be used for a patient who needs an anterior lamellar transplant, while the inner layer can be used for another patient requiring an endothelial transplant.
SNEC received approval in 2026 to begin using a single donor cornea for more than one patient under appropriate circumstances. The approach is already being used in some other Asian markets.
For Ang, the development is part of a larger transformation in corneal transplantation-from replacing the entire cornea to replacing only the portion that is diseased.
Replacing only what is damaged
The cornea is made up of several layers, each with a specific function. When the cornea becomes permanently scarred or cloudy, vision can be severely impaired and transplantation may be the only way to restore useful sight.
For decades, the standard approach was penetrating keratoplasty, or full-thickness transplantation. This involves removing the patient’s entire diseased cornea and replacing it with a donor cornea, which is secured with sutures.
While the procedure can restore vision, it also carries risks, including graft rejection, infection and other complications. The graft can eventually fail, potentially requiring another transplant.
Today, however, surgeons can take a more targeted approach.
‘The most important advancement in corneal transplantation is the shift from replacing the entire cornea to replacing only the diseased layer,’ Ang said.
If the disease affects the outer layers of the cornea, an anterior lamellar transplant can replace those layers while preserving the healthy inner portion. If the innermost layer is affected, an endothelial transplant can be performed.
This selective approach means surgeons can work through a much smaller incision, potentially reducing complications and supporting faster recovery.
It can also improve the longevity of the transplant. SNEC’s data show that more than 90 percent of selected patients retain a clear, functioning transplant beyond 10 years, while some patients continue to have clear corneas and good vision 15 to 20 years after surgery.
A thinner, sutureless transplant
One of the most refined forms of selective transplantation is Descemet membrane endothelial keratoplasty, or DMEK.
The procedure replaces only the thin, damaged inner membrane and endothelial cells rather than the entire cornea. These endothelial cells help keep the cornea clear by regulating its fluid content. When they are damaged, fluid can accumulate and cause the cornea to become cloudy.
SNEC moved from full-thickness transplantation toward endothelial keratoplasty about 20 years ago. It now performs DMEK, which uses an even thinner layer of donor tissue.
During the procedure, the donor tissue is carefully prepared, folded or rolled and inserted into the eye through a very small incision. An air bubble holds the transplanted layer against the back of the patient’s cornea until it attaches.
Unlike traditional full-thickness transplantation, DMEK is sutureless. In routine cases, the procedure may take about 10 to 15 minutes, with useful vision potentially returning within one or two weeks. Recovery from a traditional full-thickness transplant, by comparison, may take several months or up to a year.
SNEC is among the centers in Asia with extensive experience in DMEK, a minimally invasive technique that the center says offers faster visual recovery and lower complication and rejection risks than older forms of endothelial transplantation.
Making every donor cornea count
The ability to divide suitable donor tissue between recipients is particularly significant given the shortage of corneas worldwide.
But it is not as simple as cutting a cornea in half.
The process requires careful assessment of the donor tissue, specialized preparation, tracking and regulatory oversight. There is also a small risk of transmitting an infection from a donor to more than one recipient.
SNEC’s eye-banking capabilities allow donor corneas to be imported, assessed, prepared and stored before transplantation. The center has also developed specialized techniques for preparing, folding and injecting donor tissue, particularly for delicate procedures such as DMEK.
Ultimately, the objective is not simply to increase the number of transplants.
‘Donor corneas remain scarce globally,’ Ang said. ‘The aim is therefore not only to perform more transplants, but to ensure that each transplant lasts as long as possible.’
Longer-lasting grafts mean fewer patients may need another donor cornea in the future. Dividing suitable donor tissue between recipients could allow even more patients to benefit from the limited supply.
‘Selective transplantation therefore supports both improved patient outcomes and more responsible use of donated tissue,’ Ang said.
The value of a gift
The innovation also underscores the importance of corneal donation.
At SNEC, which has performed corneal transplantation for decades and carries out hundreds of procedures each year, eye-banking is an integral part of the transplant program.
For patients who have lost useful vision because of corneal disease, the donated tissue can mean a return to activities that many people take for granted-from reading and working to moving independently and seeing the faces of family members clearly again.
And with advances in selective transplantation, the potential impact of that donation is growing.
A donor cornea can be carefully matched to the specific needs of a recipient, while suitable tissue may potentially be divided to help two patients rather than one.
In a region where donor tissue remains scarce, that is more than a surgical innovation.
It is a way of making the gift of sight go further.