What is age-related macular degeneration and why should older Canadians care?

One of the leading causes of poor vision in older Canadians is a disease called age-related macular degeneration (AMD), a condition that already affects about one million people in the country, CNIB reports.

The disease accounts for 90 per cent of new cases of legal blindness in Canada, the Canadian Ophthalmological Society says. As Canada’s population continues to age, that number is expected to steadily rise – making the disease a looming public health issue.

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According to the Canadian Ophthalmological Society, this degenerative disease is far more common in people over the age of 50 – and it’s something ophthalmologists want Canadians of all ages to be conscious of this February for AMD Awareness Month.

What is AMD?

AMD is a disease of the layer under the retina and at the back of the eye – a part called the macula – which causes problems like blurriness, dark areas or distortion with the central vision, Dr. Alan Berger, member of the Canadian Ophthalmological Society and the Canadian Retina Society, explains.

“The retina is like film in a camera,” Berger explains. “For reasons related to the centre of the retina which ends up being the most important for seeing and the most metabolically active, that’s where deposits and weak areas develop which causes the central vision loss, sometimes quite acutely and quite quickly.”

This disease most often affects older Canadians, and is rarely diagnosed in those younger than 50.

Symptoms and causes

The most common symptom, Berger says, is a blotchy spot or blotchy vision – meaning part of the vision is lost, or the vision is progressively getting distorted.

People with the disease will have reduced central vision and will feel they need a bright light when reading or doing close work, the Mayo Clinic adds. Printed words become increasingly blurry, the intensity and brightness of colours decrease and they have difficulty recognizing faces.

What causes AMD is unknown, but there are risk factors that make it more likely for people to develop AMD.

First, if you have a family history of the disease, then you are more likely to get it than those who do not have such a history, Berger says.

Smoking is another risk factor, he adds – probably the biggest.

People who come from climates where they are exposed to a lot of ultraviolet light are also at an increased risk, Berger says.

Also if you’re overweight, have heart disease or high blood pressure, then your risk is also higher.

If you’re female and/or have a lighter skin colour, your risk of having AMD increases as well, CNIB adds.

Diagnosis, treatment and prevention

AMD can be diagnosed by either an ophthalmologist or optometrist. However, Berger says it’s best that people get a definitive answer by an ophthalmologist as they have access to certain vision tests that can diagnose the disease. Ophthalmologists are also the only ones who can treat the disease.

It’s important to note that there are two types of AMD: wet macular degeneration and dry macular degeneration.

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According to WebMD, having the dry form means there is presence of yellow despits, known as drusen, in the macula. It may not cause changes in vision, but as these deposits grow and/or increase in numbers, they can dim or distort vision.

The wet form involves the growth of abnormal blood vessels from the choroid, which is underneath the macula. These vessels leak blood and fluid into the retina and can cause vision distortion, blind spots and loss of the central vision.

There is no cure for either type of AMD, but they can be treated and managed, and with the help of medications, can slow the progression of the disease, Berger says.

There is also no sure way to prevent the development of AMD, but you can do a few things to reduce your chances.

Avoid smoking and managing one’s weight, blood and heart health is a good place to start, Berger says. Wearing sunglasses may also help.