AMD BASICS - TORONTO STAR

by Jennifer McIntyre

Picture this: you've just settled into your seat at the cinema. The opening credits are rolling, the lead actor's face appears - and suddenly The Man with the Great Big Head takes the seat directly in front of you. Worse, you can't leave your seat, and no amount of pleading will make Mr. Big Head move from his. That dark, shadowy blob is here to stay.

AMD, or age-related macular degeneration, feels a bit like this. The leading cause of vision loss in people age 50 and over in the Western world, with perhaps 2 million Canadians living with the disease, AMD is a progressive condition that attacks the macula, a small spot on the retina which is responsible for central vision - literally, for what's right in front of your eyes.

"Canadians are going to hear more and more about AMD" says Wendy Gibbs, Vice President, The Canadian National Institute for the Blind (CNIB). "More than 60 percent of CNIB clients live with AMD" says Gibbs, "and this number will dramatically increase in coming years given the aging of the population."

Most patients retain their peripheral vision, and AMD rarely leads to total blindness. But because the disease affects the main part of a patient's visual field, it can be devastating: AMD impairs the ability to read, watch TV, drive a car, recognize people's faces and do small detailed tasks like threading a needle or clipping fingernails.

Risk factors for AMD include age, having light-coloured skin and eyes, and having a family history of AMD. Risk also increases with smoking, poor diet, excessive sunlight exposure and obesity.

There are two forms of the disease, wet and dry, with dry AMD accounting for approximately 85 to 90 per cent of cases.

A telltale early symptom of AMD is that straight lines might suddenly appear wavy or distorted. A person might also notice blurred or spotty vision. Experts advise, however, that the condition can be present without obvious symptoms, so regular eye exams are essential.

Current treatments for wet AMD include photodynamic therapy and pegaptanib sodium injection. These treatments do not cure AMD or restore vision that has already been lost, but can delay or stop the progression of the disease.

"There is also much cautious optimism about ranibizumab, a treatment now in clinical trials." says Wanda Hamilton, of AMD Alliance International

There are presently no scientifically proven treatments for dry AMD, although there have been some reports of early favourable results in some patients in clinical trials for rheopheresis, a blood filtration process.

Perhaps most essential for those with AMD is a healthy diet, and vitamin therapy, with a specific focus on antioxidants. In October 2001, the Age-Related Eye Disease Study (AREDS) showed that patients who took a combination of vitamins C and E, beta-carotene, zinc and copper had a startling 25 per cent reduction in the progression of their disease.

"It has been known for quite some time that a diet rich in antioxidants is good for your eyes," says Dr. Alan Cruess, Head of Ophthalmology at Dalhousie University.

"The best advice we can give," says Cruess, "is to quit smoking and to maintain a healthy diet and lifestyle. Smoking can effectively triple your risk of vision loss through AMD"

Cruess suggests a diet that includes "lots of citrus, leafy greens, rich in vitamins C and E, beta-carotene and zinc."

There is no cure for AMD, but it is treatable and - possibly - preventable. Regular eye examinations, and reducing modifiable risk factors such as smoking and obesity, may help ensure that severe vision loss is not an automatic part of growing older.