Age-related macular degeneration
Age-related macular degeneration (AMD) is a disease associated with aging that gradually destroys sharp, central vision.
Central vision is needed for seeing objects clearly and for common daily tasks such as reading and driving. The middle of the retina is called the macula, the part of the eye that allows you to see fine detail. When you have AMD, the macula gets damaged.
AMD causes no pain. In some cases, this disease advances so slowly that people notice little change in their vision. In others, the disease progresses faster and may lead to a loss of vision in both eyes. This eye affection affects an estimated one million Canadians and is more common in people over 50.
Types of AMD
Dry AMD occurs when the light sensitive cells in the macula slowly break down. It progresses over a matter of years. With less of the macula functioning, central vision diminishes. Dry AMD is more common than wet AMD.
Wet AMD occurs when abnormal blood vessels behind the retina start to grow and begin to bleed, damaging the macula. The blood and fluid raise the macula from its normal place at the back of the eye. Damage to the macula occurs rapidly which directly causes loss of central vision.
How to detect AMD
Because AMD causes no pain, it may be difficult to diagnose it. However, the following symptoms may be good indicators:
- Straight lines that appear wavy or crooked
- Blurred or fuzzy vision
- Difficulty seeing at a distance
- Decreased contrast or colour sensitivity
- A small, but growing, blind spot in the centre of vision
- You can also do a simple test at home: The Amsler grid
This tool is used for monitoring for early signs of AMD. The Amsler Grid is not a substitute for regularly scheduled eye exams. If you are concerned about AMD, you are over 50, or you have risk factors for the disease, you are encouraged to do the Amsler test on a regular basis. Download the pdf.
Cover one eye and stare at a black dot in the center of the grid (stand 30-35 centimeters away). If you wear glasses, keep them on. If you wear bifocals, use the bottom or reading portion of the lens. Test the other eye in the same way.
|This is a normal Amsler Grid||This is how it might look if you had AMD|
While staring at the dot, you may notice that the straight lines in the pattern appear wavy. You may notice that some of the lines are missing. These may be signs of AMD.
Do not depend on the grid displayed above for any diagnoses. If you notice this condition or other changes to your vision, contact your eye care professional. Regular checkups are essential, since AMD can be present without symptoms.
- Age: studies show that people over age 50 are clearly at greater risk than other age groups.
- Smoking: Smoking is major risk factor for AMD
- Obesity: Research studies suggest a link between obesity and the progression of AMD.
- Race: Whites are much more likely to lose vision from AMD.
- Family history: Those with immediate family members who have AMD are at a higher risk of developing the disease.
- Gender: Women appear to be at greater risk than men.
- Sun: Wear a hat and sunglasses with UV protection