Up to 50 per cent of people with glaucoma don't realise they have it.
Glaucoma Australia estimates 300,000 Australians are living with the degenerative eye disease, but about half are completely unaware.
Waratah Private Hospital ophthalmologist Dr Rajeev Chalasani, who is also a lecturer with the University of Sydney, said the lack of glaucoma symptoms in the early stages of the condition meant it was easy for the disease to go undiagnosed.
"Glaucoma is one of those conditions that's very common and becomes more common as people grow older," he said.
"The hardest thing about glaucoma in the early stages is that it doesn't give you any symptoms, and people can walk around and not realise they have it.
"The difficulty is, glaucoma only starts to cause symptoms once it is more advanced, and then you can't reverse the damage that has already been done by that point."
Dr Chalasani hopes World Glaucoma Week (March 7-13) will help people realise the importance of regular eye check-ups.
"Early diagnosis and treatment is so important to prevent that irreversible damage," he said.
"We usually recommend everyone the age of 40 and onwards schedule regular checks with their optometrist. They will have all the equipment which can pick up something that might be suspicious.
"They can then refer the patient on to us, the ophthalmologist."
Dr Chalasani said it was still "quite uncommon" for glaucoma to appear before the age of 50, but everyone, especially those with family history of the disease, needed to be vigilant.
Glaucoma Australia reports people are 10 times more likely to develop glaucoma if they have a family member with the condition.
First degree relatives of glaucoma sufferers have an almost 25 per cent chance of developing the disease in their lifetime.
"There are a lot of good treatments now that an prevent the majority of people from losing their vision, if they're treated early," Dr Chalasani said.
"Glaucoma is strongly related to pressure in the eye, and if it's very high someone could lose their vision within a few months. Most people only have borderline or slightly elevated pressure, and it can build up over a number of years.
"The more common scenario, mildly elevated pressure, mostly presents with symptoms like loss of peripheral vision, which is vision out to the side.
"That's another reason people don't always necessarily realise there's a problem - their central vision is relatively reserved until right at the end."
Dr Chalasani explained that glaucoma causes very slow damage to the optic nerve, which sends vision signals back to the brain. As the nerve is slowly damaged, vision is lost, starting with peripheral.
"We still don't know all the factors that cause glaucoma, but ageing and genetics play a big role," he said.
"All the ways we have of treating the condition are about lowering the pressure in the eyes, and for most people that does seem to stop the progression of the disease."
Dr Chalasani said treatment was always catered to the specific needs of the patient, based on the advancement of their glaucoma and the pressure on their eyes.
He said the first step was usually eye drops which lower pressure on the eye. The next step is laser treatments, and if the condition is even more severe and has not responded to eye drops or lasers, operations are an option.
Dr Chalasani said the most vital thing for locals to remember this World Glaucoma Week was the importance of checking in with their optometrist to screen for the condition.
He said plenty of helpful information was available at the Glaucoma Australia website: glaucoma.org.au.
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