SINGAPORE - Patients who have undergone cataract surgery have to apply steroid eye drops every three to four hours, for up to one month or longer, in order to control eye inflammation that occurs after the surgery.

But it is common for patients to find eye drops difficult to apply, or to use them wrongly or forget about them entirely. And when eye inflammation is not controlled properly, it can lead to pain, blurred vision and, in severe cases, even blindness.

Researchers at the Singapore National Eye Centre (SNEC) and Singapore Eye Research Institute (Seri), in collaboration with Utrecht University in the Netherlands, have worked together since 2014 to come up with a way to address this problem.

They have developed a new treatment that can completely eliminate post-cataract surgery eye inflammation, and remove the need for steroid eye drops after surgery.

In this treatment, liposomal prednisolone, a steroid wrapped in layers of lipid nanoparticles, is injected onto the eye at the end of cataract surgery.

The lipid layers make liposomal prednisolone more attractive to inflammatory cells, which are activated in response to surgery. The inflammatory cells engulf the liposomal prednisolone, after which the steroid is released inside the cells to reduce inflammation.

The lipid particles are 100 nanometres in size, which is 1,000 times smaller than a strand of hair.

This drug treatment fits seamlessly into cataract surgery, completely eliminating inflammation after surgery with no side effects, said Dr Wong Chee Wai, the principal investigator for the study, at a media briefing on Tuesday (Aug 3).

Added Dr Wong, a consultant at the surgical retina department in SNEC: "Even for young people with good vision, it's not easy to accurately put eye drops into the eye. It's even more difficult for the elderly, who might have poor vision and unsteady hands."

Most patients who undergo cataract surgery are aged 50 and above.

A cataract is the clouding of the eye's lens, which is normally clear. This can lead to vision problems including dim or blurry vision and reduced night vision. In cataract surgery, the cloudy lens is replaced with an artificial lens.

Around 17,000 cataract surgeries were performed at SNEC in 2019, and Dr Wong expects this number to rise due to Singapore's ageing population.

Professor Tina Wong, head of the ocular therapeutics and drug delivery group at Seri, and co-principal investigator for the study, said the new drug treatment is a welcome alternative for doctors too, as it removes the problem of non-compliance when patients have to take eye drops.

She said: "If you tell them to use these eye drops every three hours for one month... People will forget."

Dr Wong added that patients can accidentally injure their eye while using eye drops or contaminate the bottle, which can lead to eye infection.

Steroid eye drops also have limited efficiency in treating eye inflammation, as the drug may not reach the site of inflammation, Dr Wong said. In fact, less than five percent of the drug actually manages to do so.

The drug can also be easily removed from the eye through tears or blinking, he said.

In comparison, the new drug treatment is more effective as it selectively targets inflammatory cells within the eye. The lipids around the drug also keep it from being dispersed before it reaches the inflammatory cells.

The team demonstrated the safety and effectiveness of this treatment with its first round of clinical trials that ended last year, and hopes to conduct more clinical trials with other centres in the next few years.

Prof Wong, who is also the head of the glaucoma department at SNEC, said it would take six to eight years for the drug treatment to be commercialised.

Housewife Eyok Raiyah Abubakar, 64, who had cataract surgery for her right eye at the end of last year, and volunteered to receive this drug treatment under the clinical trials, said she was pleased with the surgery and its results.

She said in Malay: "It was a very good operation with no complications."

Madam Eyok, who previously had cataract surgery for her left eye without the new drug treatment, added that it was more convenient and comfortable not to use eye drops frequently after surgery.

"I was very happy when the doctors told me that this new treatment is very fast and more convenient for me."