A University of Hong Kong eye doctor said on Friday that ROTA technology is more effective than conventional tools at detecting optic nerve degeneration in glaucoma, an irreversible eye disease that can lead to blindness.

Dr Christopher Leung, from the Department of Ophthalmology at HKU Medicine, said their screening project, which started eight months ago examining 1,159 Hong Kongers over the age of 50, revealed a high rate of glaucoma, with eight percent diagnosed with the condition.

He said that early diagnosis is necessary as the optic nerve cannot be regenerated, adding that ROTA can detect glaucoma in patients earlier than older methods.

"ROTA is a tool that allows us to see the nerve on the retina. In the old days, before we had this technology, we relied on examination of the optic disc," he said.

"We relied on the optical imaging device to measure the thickness of the nerve, fibres on the retina, but ROTA gives us a new dimension about the texture, about the anatomy, about the pathology of the axonal fibre bundles, the tissue of the optic nerves on the retina."

Dr Leung said that 90 percent of the diagnosed patients were unaware of their condition because symptoms are difficult to detect.

"Glaucoma typically affects side vision before it affects the central vision. The very early symptoms for most patients are actually asymptomatic. They do not have any symptoms, but if patients are careful about what they see, they would actually notice that they would not be able to see well when the environment is dim," he said.

"But most people will think [the environment is] dim which is why they couldn't see well; they are not aware that this is related to glaucoma, and that's why a lot of patients are not aware of it."

HKU’s ophthalmology department and the international eye care non-profit group Orbis plan to complete their ROTA project by the end of year.