I've got my eye on you, mac

Spiking rate of age-related macular degeneration has spurred new research to fight blindness

By Katherine Addleman

Currently, hundreds of thousands of elderly Canadians are blind sided by age-related macular degeneration (ARMD) and the future looks even bleaker. According to the Canadian National Institute for the Blind (CNIB) and the ARMD Alliance International, another 80,000 new cases are expected to be diagnosed next year in this country � an annual figure that will triple 25 years down the road.

A new report from Johns Hopkins University in Baltimore and the Eye Diseases Prevalence Research Group revealed the sobering trend in Europe, Australia and the US as well by pooling data from several large, population-based studies carried out over the last two decades. The study was published in the April issue of the Archives of Ophthalmology.

Among diseases that cause blindness, ARMD is definitely the frontrunner in people over 65 � especially those of European descent. It's the leading cause of vision loss in Canada, striking more people than glaucoma and cataracts combined. In ARMD, the macula � the central area of the retina � deteriorates so that central vision fails gradually or, sometimes, very suddenly. With the macula gone, only peripheral vision remains.

SPOT THE RISK
Some factors known to elevate the risk of ARMD can be modified early on to stave off the disease. These include cigarette smoking, obesity and high lipid levels. Earlier this year, investigators at Harvard University found that elevated C-reactive protein is also an independent warning sign.

Dr Thomas Sheidow of the University of Western Ontario and St Joseph's Healthcare Centre in London, Ontario, says "identifying people at high risk is a good strategy." "Patients who are at risk or who have early macular disease should check their vision every week using the Amsler grid, a simple test that uses a graph paper-like design," he recommends. Retinal specialist Dr Patricia Harvey, assistant professor in the Department of Ophthalmology at the University of Toronto, agrees. Dr Harvey also educates organizations for the elderly about ARMD prevention and treatment, and stresses the benefit of this strategy.

KEEP HOPE IN SIGHT
Dr Sheidow notes: "recent research has come up with new therapies to help improve vision impaired by ARMD � through food and vitamin supplements." One study in the Archives of Ophthalmology shows that people eating more nuts and fish were less likely to suffer severe ARMD than those who wallowed in high saturated fat diets. The worst culprits, processed baked goods, were linked to double the rate of disease progression. Another study in the journal Optometry found that dark green vegetables containing lutein (spinach, collard greens, kale) could have therapeutic properties in this disease. Dr Sheidow highlighted the AREDS study, a large investigation that found that patients with moderate to severe ARMD could slow the onslaught of disease if they took both antioxidant minerals and vitamins, including beta carotene, vitamin C, vitamin E, copper and zinc. In addition to these, Dr Sheidow also recommends adding lutein to the arsenal. He notes: "The AREDS study didn't come up with definitive information about lutein because no high-dose lutein supplement was available when the study was designed. But now there are lutein supplements, and large-scale research now underway will likely find that lutein is beneficial."

In the wet form of ARMD, which affects about 10% of patients, laser treatment can be helpful. It's especially useful with a new light-activated agent called verteporfin. "Verteporfin was approved for ARMD by Health Canada in 2000, and looks quite promising in certain cases," according to Dr Sheidow. Dr Harvey agrees with this assessment and adds that verteporfin therapy not only preserves, but can even improve the vision of some patients.