SINGAPORE: A multi-country clinical trial studying surgical treatments for glaucoma has been launched, making it the first Asia-wide trial looking into how the eye disease is treated in the region, the Singapore National Eye Centre (SNEC) announced on Tuesday (Nov 7).
Also known as the "silent thief of sight", glaucoma is the leading cause of irreversible blindness worldwide, with little to no obvious symptoms appearing until damage has occurred.
The eye disease affects about 70 million people globally, with this number expected to rise to 80 million by 2020. In Singapore, about 3 per cent of people over the age of 50 have glaucoma, with its prevalence increasing with age. According to SNEC, it currently affects up to 12 per cent of those aged above 70.
Glaucoma occurs when the eye fails to drain fluid as well as it should, similar to a clogged drain. As a result, fluid builds up in the eye and begins to damage the optic nerve.
In view of this, a trial is being conducted to compare two surgical treatments for advanced cases of glaucoma, with the aim of studying their long-term outcomes and complication rates in an Asian population.
Currently, the conventional method of lowering eye pressure is trabeculectomy, which involves making a small opening in the sclera - or the white of the eye. This in turn creates a small bubble on top of the conjunctiva - or the mucous membrane covering the front of the eye - allowing eye fluid to be drained out and absorbed by nearby blood vessels around the eye.
However, the incision might heal and close up on its own, preventing fluid from draining out. And this faster "scarring response" is a problem that is more commonly found in Asians compared to Caucasians, said Professor Aung Tin, the overall trial principal investigator of the Glaucoma Asia Study.
"It’s known, for example, that Afro-Caribbean populations have the greatest scarring response followed by Asians, and Caucasians have the least scarring response," said Prof Aung, who is also the deputy medical director of research at SNEC.
"So, unfortunately in Asians, there’s often a lot of scarring after surgery and this causes intraocular pressure to go up after a few years," he said.
As such, the trial plans to study the drainage implant technique, where a small drainage tube is inserted in the eye, creating a collection area. This allows fluid to flow into the area, where it is then absorbed into nearby blood vessels - overcoming the scarring issue faced by patients who undergo trabeculectomy.
Funded by the National Medical Research Council, the Singapore-led trial aims to recruit 300 patients across more than 10 Asian countries. This includes a target of at least 60 participants from Singapore.
One such participant is 70-year-old Mr Lum, who underwent the drainage implant surgery earlier this year. Since then, his eye pressure has been greatly reduced, he said. The project sales manager discovered that he had glaucoma during a regular check-up after a cataract operation.
"I think there's a marked improvement, it's fantastic. If anybody has glaucoma I think they should opt for (the trial) because it saves your eyesight," Mr Lum said.
The results of the multi-country trial is expected to be ready by 2023.
Interested participants can call the Singapore Eye Research Institute hotline at 6576 7311 for more information.