Type of glaucoma linked to increased risk of dementia, study finds

Australian researchers have established a link between a type of glaucoma and cognitive impairment (the stage between the expected cognitive decline of normal ageing and the more serious decline of dementia).

A study published online in the British Journal of Ophthalmology on Monday has found a type of glaucoma called normal-tension glaucoma is associated with an increased risk of cognitive impairment and possibly dementia.

Glaucoma is a condition that damages your eye’s optic nerve. It’s one of the most common eye issues over-60s face — in fact, an estimated 300,000 Australians are currently living with the disease (but more than 50 per cent have not been diagnosed). No one knows the main cause of glaucoma, however it’s often linked to a build up of pressure inside your eye — although that’s not the case when it comes to normal-tension glaucoma.

The disease pathway for low- or normal-tension glaucoma — a subtype of primary open angle glaucoma — is not fully understood, but the authors say their findings suggest that it may share similar neurodegenerative pathways with dementia. In fact, previous studies have found a link between primary open angle glaucoma and dementia.

Other primary open angle glaucoma subtypes include high-tension glaucoma, where pressure in the eye is high. Normal-tension glaucoma is more common in Asia, while high-tension glaucoma is more common in Europe.

The reason why we’re telling you this is because two of the studies that showed a link between primary open angle glaucoma and dementia included a large number of people with Asian ethnicity. This led the authors to wonder whether it may be specifically normal-tension glaucoma that is linked to cognitive impairment and dementia.

So, to find out, the researchers used the Australian and New Zealand Registry of Advanced Glaucoma to randomly select 248 patients aged at least 65 years, who had normal-tension glaucoma. They were then matched by age and sex with 349 patients with high-tension glaucoma.

The patients had to participate in a health questionnaire and cognitive assessment over the phone, before undergoing a cognitive screening test. The researchers found that cognitive impairment was more common in patients with normal-tension glaucoma than it was in those with high-tension glaucoma.

“Our finding of an association between normal-tension glaucoma and cognitive impairment supports a growing body of evidence suggesting an association between normal-tension glaucoma and dementia,” the authors said.

The authors, however, highlighted that this was an observational study, and they can’t rule out “the possibility that results were affected by unobserved differences in clinical features or cognition of patients who could not be contacted or did not participate”.

IMPORTANT LEGAL INFO This article is of a general nature and FYI only, because it doesn’t take into account your personal health requirements or existing medical conditions. That means it’s not personalised health advice and shouldn’t be relied upon as if it is. Before making a health-related decision, you should work out if the info is appropriate for your situation and get professional medical advice.