IT COULD be robbing your sight slowly, but you may not even know until it's too late.
Glaucoma, or damage to the optic nerve at the back of the eye, is one of the leading causes of blindness worldwide, yet if it is detected early it can be easily treated.
"Like any disease, the earlier you catch it, the better the long-term prognosis," says Prof Colm O'Brien, a consultant ophthalmologist at the Mater Misericordiae Hospital. He will speak in Dublin on Thursday to raise awareness of glaucoma, which affects around 70 million people worldwide.
The condition - where a build-up of pressure within the eye damages the nerve linking the eye to the brain - develops slowly over several years. There are no noticeable symptoms, so people tend not to know that there's a problem in the early stages, he explains. "Very few people with glaucoma get pain and discomfort and that's probably an issue. If they did they would get themselves tested far more frequently," says Prof O'Brien.
Most at risk are the over-50s, as age-related fluid build-up inside the eye starts to damage information-carrying cells called neurons in the optic nerve. "If you lose any of these neurons, you don't ever get them back," says O'Brien.
More rarely, the condition can crop up in younger people, sometimes because of a malformation in the eye shape, or after an injury that allows fluid to accumulate in the eye. People with diabetes, short-sightedness or high blood pressure are also at risk of developing glaucoma, adds O'Brien, and heredity can play a role.
"If you have a family history, there's an increased risk of your getting it, particularly if a number of people have it."
O'Brien suggests that from middle-age - or younger for high-risk individuals - people should ask to be screened by an optician who can test for the features of glaucoma.
"From the patient's point of view, it would be getting their eye pressure measured usually with an air puff to the eye," he says. "It's pain-free and only takes a few minutes."
The optician can also look at the nerve at the back of the eye and pick up on any signs of a problem, he adds. "If there's any concern they might do a test of the side vision, because that's what gets damaged in early glaucoma."
O'Brien stresses that, with early detection, you have time on your side.
"It can take five to 10 years for the rise in pressure to cause irreversible loss of vision. That means if you identify it during those five to 10 years you are going to protect that person's vision," says O'Brien.
He notes that people with glaucoma respond well to treatment designed to help prevent further nerve damage and sight loss.
"It's relatively easy to control the patient's eye pressure with eye drops, and the majority of people do very well with that. We are very fortunate that in the last 10 to 20 years we have had a number of eye drops come on the market."
O'Brien also notes that you can improve your odds by maintaining a healthy lifestyle, with plenty of circulation-boosting exercise, a good diet and no smoking.
Although there is no cure at present, recent research on animal models has used tiny molecular scaffolds to help regenerate the damaged optic nerve. However, O'Brien says we won't see a similar treatment for humans anytime soon.
"We are optimistic, we are learning a lot from the people doing research on spinal cord injury and brain injury," he says.
"If they can manage to regenerate nerve fibres and restore the spinal cord we will be the beneficiaries of that type of research.
"So while at the moment there's nothing on the horizon that's near coming into clinical trials, I would be hopeful that within the next 20 years something will come out."
In the meantime, he urges people to go for screening, particularly if they fall into higher-risk categories, so the condition can be picked up quickly if present.
"Treatment works, so the key is detection. If we can diagnose it early, we have every chance of preserving vision into a good old age."
Consultant ophthalmologists Colm O'Brien and Aoife Doyle will speak at a public meeting this Thursday, March 6th at 6.30pm in the Davenport Hotel in Dublin 2.
The event marks the first World Glaucoma Day, supported by the All Eyes on Glaucoma campaign, which is run by Pfizer.
