The cornea is a transparent dome-shaped structure covering the front part of the eye. As the eye’s outermost layer, the cornea functions like a window that controls and focuses the entry of light into the eye.

Cloudy cornea due to infection, eye injury, congenital conditions, or age-related degenerative eye disease prevents light rays from reaching the light-sensitive portion of the eye called the retina. This may cause the patient to suffer from poor vision or even blindness.

In eyes with cloudy corneas, as long as the nerve and retina at the back of the eye are still healthy, patients can benefit from a corneal transplant.

Local supply shortage

A corneal transplant involves replacing the cloudy unhealthy cornea with a thin layer of healthy cornea from a donor to offer someone the gift of sight. The eyeball is kept intact in the process of donation.

“A healthy donor cornea replaces the patient’s opaque and diseased one. When performed by a trained ophthalmologist, the procedure has the potential to fully restore vision,” said Dr Anshu Arundhati, Senior Consultant, Corneal & External Eye Disease Department, Singapore National Eye Centre (SNEC).

<<Dr Anshu Arundhati, Senior Consultant, Corneal & External Eye Disease Department, Singapore National Eye Centre (SNEC)>>

Close to 500 such transplants are performed annually in Singapore. However, the number of donors has been on the decline in recent years and donations fell to a five-year low of 141 in 2019, said Dr Anshu, who is also the Clinical Director at the Singapore Eye Bank.

While the Singapore Eye Bank has been able to rely on reputable overseas eye banks, there is still an urgent need to build up the local supply of donated corneas to facilitate transplants.

“Thankfully, the waiting time for a transplant has not been adversely affected despite the shortage of local tissue because of the overseas pipeline we have maintained. However, we should be cognisant of the fact that this supply can be disrupted at any time, particularly during a pandemic like COVID-19,” said Dr Anshu.

Who can donate?

Just about anyone can be a cornea donor. There is no blood type requirement. A person’s age, eyesight and eye colour do not matter either.

But to ensure the safety of the recipients and medical team, all donors undergo stringent screening. Individuals who have had communicable diseases and infections, certain cancers and neurological conditions, eye diseases, and other illnesses that may compromise the safety and quality of the corneas will not be able to donate their corneas.

Donation procedure

A recent review of potentially suitable cases over the last three years revealed some common reasons behind why relatives decline the donation on behalf of their deceased family member. These include the family wishing to keep the body intact, relatives being too distraught when approached about the donation, or family members not wanting to put the deceased through any further “suffering”.

An understanding of the process of donation may ease some of their concerns.

Cornea removal takes about 30 to 45 minutes, and is usually performed shortly after death. Under sterile conditions, the cornea disc and a small rim of surrounding scleral tissue (white part of the eye) are removed and transferred to a special cornea storage solution, and stored at low temperatures.

The body of the deceased is treated with utmost respect throughout the entire process. The removal of the corneas will not result in any form of disfigurement, allowing for an open casket funeral service.

Developing alternatives

There is currently no acceptable artificial replacement alternative for a human cornea, though several groups around the world are actively seeking solutions to counter the global donor shortage.

For example, clinicians and scientists at SNEC and Singapore Eye Research Institute are currently working on tissueengineered constructs.

Primary human corneal endothelial cells are cultivated, expanded, and subsequently transferred to a carrier substrate for implantation. If this is successful, a pair of donor corneas can create up to 80 constructs and potentially alleviate the donor cornea supply crunch in the future.

Donating your cornea

After the passing of a loved one, you may be too distraught to make the call for cornea donation, or may wish to keep his or her body intact. If your loved one had completed an Organ Donor Card or previously communicated a wish to donate his or her corneas, the decision may be easier for your family.

Make your intentions known

· Anyone above 18 years of age can pledge to donate any organ or tissue upon their death. Fill out an Organ Donor Card issued by the Ministry of Health and carry it with you at all times. Becoming a donor is a personal decision.

· The Singapore Eye Bank has an active Hospital Eye Donation Programme at Singapore General Hospital, Changi General Hospital, National University Hospital and Tan Tock Seng Hospital.

· Singapore law allows the deceased’s family to make the decision of cornea donation on his or her behalf. Counsellors from the Singapore Eye Bank will approach the family to seek consent.

Remain on the Human Organ Transplant Act (HOTA) scheme

· In the event of death from any cause, the HOTA allows for the kidneys, heart, liver and corneas to be removed for the purpose of transplantation. HOTA covers all Singapore Citizens and Permanent Residents aged 21 years and above who do not have mental disorders, unless they have opted out of the scheme.