Glaucoma Breakthrough a Step Towards 'Stopping People Going Blind With Age', Researchers Say

By Selina Ross

Australian researchers studying glaucoma have had a breakthrough, identifying new genetic markers that increase the risk of developing the damaging eye disease.

Glaucoma is the leading cause of irreversible blindness in the world and affects about 300,000 Australians.

The study of more than 134,000 people from Australia and around the world found 101 genetic markers that influence the fluid pressure in a person's eye (intraocular pressure).

The researchers found that 53 of the genetic markers directly increase the risk of developing glaucoma, particularly advanced glaucoma that tends to cause blindness.

Professor Alex Hewitt, an ophthalmologist and medical researcher based at the University of Tasmania's Menzies Institute for Medical Research, said the study showed people with a large number of genetic markers had an almost sixfold increased risk of developing glaucoma compared to someone with fewer gene variants.

"About two out of three people with glaucoma have high pressure in their eye," Professor Hewitt said.

"One easy way of conceptualising glaucoma is that pressure in the front part of the eye puts pressure on the back part of the eye, which damages the nerve at the back of the eye."

'One step closer to stop people going blind'

People with glaucoma typically lose their peripheral vision and it can be hard for them to notice the disease in its early stages.

There is no predictive test for glaucoma currently available.

"It's usually a gradual loss of that peripheral vision that sneaks up on you, hence glaucoma's labelled the 'sneak thief of sight'," Professor Hewitt said.

"Our new research will improve our ability to identify people at risk of developing glaucoma.

"And this takes us one step closer to a preventative treatment that could stop people from going blind as they age."

If caught early, the progression of sight loss can be slowed, but experts believe about half the people who have glaucoma are undiagnosed.

The findings are expected to lead to better screening, which would likely start when people reach middle age.

Professor Hewitt said the ability to profile people on a genetic basis would show "who needs stringent screening and who needs just routine surveillance".

"I don't think we're terribly far away from being able to do it," he said.

"And, excitingly, next year we'll be starting a large program grant that's funded through the National Health and Medical Research Council that will really allow us to build the evidence base for these genetic tests in rational screening of glaucoma."

In the longer term, the work could also lead to better drug treatments.

"It means that we can identify new therapeutic targets for glaucoma," he said.

'It will be a wonderful help to sufferers'

Helen McNeice, who has had glaucoma for 25 years, has endured multiple eye surgeries.

Glaucoma runs in her family.

"My mother had it, my grandmother had it, my aunt had it and we think that my father had it too, my sister has it," she said.

Mrs McNeice has had periods between surgeries of not being able to drive.

"It takes your independence away from you. You can't drive, I couldn't see to read the paper, magazines," she said.

"I couldn't see to pay the bills. People don't really understand how it affects you."

Mrs McNeice welcomed the research findings.

"I think it will be wonderful if they are able to do this for other people," she said.

"I know it's not going to help me but it will help a lot of other people. They need to have something and I think it will be just great."

Research began in Tasmania with the Glaucoma Inheritance Study in Tasmania in the 1990s and the recent work is the largest-ever genetic study of glaucoma.

It was led by the QIMR Berghofer Medical Research Institute in Queensland in collaboration with the Menzies Institute and the Flinders Centre for Ophthalmology, Eye and Vision Research in South Australia.