Patients with dry eyes who don’t respond to commercial eye drops now have an effective new option
For almost three years, she struggled to find ways to deal with her dry eyes. Each time she blinked, Mrs Ng Guan Lee felt as if a knife was slicing a layer off the surface of her eye.
Sometimes, the pain got so bad, it kept her up at night. Then, relief came in the form of eye drops made from her own blood.
“The plasma eye drops are really soothing to my eyes. They take away the dryness and don’t irritate my eyes as they are made of my own protein,” said Mrs Ng.
Her condition was brought on by multiple operations to treat a retinal problem in her eye. Besides using over-the-counter lubricating eye drops to relieve the symptoms, she tried to avoid air-conditioned areas where possible, and even installed a humidifier in her bedroom so her eyes would not become dry. However, the frequent use of eye drops brought on other problems.
“The commercial eye drops relieved my symptoms only temporarily, so I was using them every half an hour, especially when I had to work on my computer for a long period. After a while, I started getting a gritty feeling in my eyes. On some days, my eyes became so inflamed, I had to rush to the emergency department,” said the 55-yearold procurement manager in the telecommunications industry.
Commercial products are not able to completely replicate the tears we produce, which contain many proteins. Researchers from the Singapore Eye Research Institute (SERI) and Singapore National Eye Centre (SNEC) believe that the closest substitute is plasma – the yellowish fluid in blood that carries all the different blood cells.
“While its composition is not perfectly identical to tears, plasma contains many proteins that are present in tears. The proteins provide a normal, anti-inflammatory environment for the eye surface and, therefore, plasma could well be a tear substitute,” said Dr Louis Tong, Consultant, SNEC, and lead investigator of the study.
Oh, what a relief!
Dry eye, a common condition that affects the quality of life of its sufferers, is caused by multiple factors such as ageing, trauma to the eye or certain disease conditions. It may also be a side effect of certain drugs or treatment. For example, Mr Hartono Hoesny, 61, developed dry eyes after undergoing a bone marrow transplant for cancer.
He also tried several over-thecounter eye drops and eye gels, but found relief only when he joined the study and started using the plasma eye drops.
Patients in the study undergo a painless one-hour procedure, similar to a blood donation, to extract the plasma from their blood. The plasma is then placed in narrow tubes clamped about an inch apart.
Stored in the freezer
Patients store these tubes in the freezer and break off the required segments for their daily use. Some, like Mr Hoesny, even double-bag them before keeping them in the freezer to ensure they do not get contaminated.
The improved comfort experienced by patients is backed by observations of the study team.
“We observed reduced damage on the epithelial cells (cells at the surface of the eye) after six weeks of treatment. These are definitely encouraging results. When we recently announced the findings at an international meeting, the audience was equally enthusiastic,” revealed Dr Tong.
The team is optimistic that treatment based on this principle may, in future, become the gold standard in dry eye treatment for challenging cases. In the meantime, the team will continue with an observational study for one to two years to look at the long-term effects of the treatment.
The plasma eye drops will be manufactured at the Blood Services Group (BSG) of Health Sciences Authority of Singapore, which will also aid in storing them for the individual patient.
“As the freezing facility at BSG is reliable and more spacious, patients can have half their stock of plasma eye drops stored there. When they run out of their supply about five or six months later, they can collect the other portion without having to undergo another plasma extraction process,” explained Dr Tong.
For patients like Mr Hoesny, it is good news indeed. “The plasma eye drops are purely from our plasma, so they are very safe and effective. I was lucky to be part of the study. Although I will now need to pay for them as the study period is over, it will still be a lot cheaper than buying over-the-counter eye drops which are not completely effective,” he said.
Why do the eyes get dry?
A flow of tears is necessary to provide constant moisture and lubrication to the eyes. Tears are made up of:
- Water (for moisture)
- Oils (for lubrication)
- Mucus (for even spreading)
- Antibodies and special proteins (for resistance to infection)
Special glands located around the eyes secrete these components. An imbalance of these can cause dry eyes.
How do I know my eyes are dry?
When tears are not effective in lubricating your eyes, you may experience:
- Light sensitivity
- A gritty sensation
- A feeling of sand in the eye
- Blurring of vision