What is Age-related Macular Degeneration?
Age-related macular degeneration is a chronic disease of the central part of the retina, the macula that affects a person’s central vision. It is the leading cause of blindness in the Western World. Researchers estimate that over 2 million Canadians have some form of age-related macular degeneration. There are two forms of age-related macular degeneration. Dry age-related macular degeneration and wet age-related macular degeneration.
Dry AMD: Dry age-related macular degeneration occurs when cells in the central part of the retina start to break down, causing a gradual decrease in central vision. Drusen, accumulation of metabolic waste in the retina, are also evident in dry age-related macular degeneration.
Wet AMD: Wet age-related macular degeneration is caused by the growth of abnormal blood vessels that leads to the leakage of fluid or blood into the macula, the central part of the retina. Wet age-related macular degeneration causes a rapid, often dramatic loss of central vision.
Neither dry age-related macular degeneration nor wet age-related macular degeneration causes total blindness, only a decrease or loss of central vision. People with age-related macular degeneration may notice changes in their ability to read books, see street signs or to see details on a person’s face; however, they are able to walk and move around safely.
What are the symptoms of AMD?
- • Gradual loss of central vision
- • Distortion of straight lines
- • Blurry vision when reading
- • Rapid-onset loss of central vision
- • Blind spot in or near the central vision
What are the risk factors for AMD?
- • Age
- • Smoking
- • Family history of AMD
- • UV light exposure
- • Blue light exposure
(short wavelength visible light)
- • Diets high in sugar and refined carbohydrates
- • Excess weight or obesity
- • Gender (women are at a higher risk than men)
- • Eye colour (light eyes are at higher risk)
- • Race (Caucasians are at a higher risk)
- • Diabetes
- • Cardiovascular disease
Prevention of AMD:
- • Eat foods rich in lutein and zeaxanthin
- • Increase your vitamin C, vitamin E, beta- carotene and zinc intake
- • Eat fish with high levels of omega-3 fatty acids
- • Engage in physical activity or exercise
- • Maintain a healthy weight
- • Protect your eyes from UV light
- • Don’t smoke
What is the current treatment for dry AMD? The current treatment for dry AMD aims to slow the progression of the disease. If you have dry AMD, you are advised to modify your diet and lifestyle by eating foods rich in specific antioxidants and omega-3 fatty acids, to take AREDS-based ocular vitamins, to wear sunglasses and to stop smoking. Optometrists and ophthalmologists advise people with dry AMD to use an Amsler grid on a daily basis. The Amsler grid is a simple test that allows a person to notice subtle changes in vision that can be a sign of progression of dry AMD to wet AMD. What is the current treatment for wet AMD?
There are several treatment Options for wet AMD, depending on the stage of the disease and the location of the abnormal blood vessels. To date, the only treatment that has shown an improvement in visual acuity is anti-VEGF (vaso-endothelial growth factor) medication that is injected into the eye.
Anti-VEGF medications block the protein (VEGF) that is responsible for new blood vessel growth. In wet AMD, these medications help stop the growth of the new blood vessels in the retina. They may slow the progression of vision loss and, in some cases, even improve vision. An ophthalmologist will inject the medication into the eye. Multiple injections, given on a monthly basis are often required for the treatment to be effective.
Research References: AREDS Research Group, The relationship of dietary carotenoid and vitamin A, E, and C intake with age-related macular degeneration in a case-control study,1225-32.
Moeller S., N. Parekh, L. Tinker, C. Ritenbaugh, B. Blodi, R. Wallace, and J. Mares. 2006. Association between intermediate AMD and lutein and zeaxanthin in CAREDS. Arch ophthalmol 124: 1151-62.
Areds Research Group. The relationship of dietary omega-3 long-chain polyunsaturated fatty acid intake with incident age-related macular degeneration: AREDS report no. 23. Arch ophthalmol 126: 1274-9.
Seddon, J., J. Cote, N. Davis, and B. Rosner. 2003. Progression of ARM associated with BMI, waist circumference and waist, hip ratio. Arch ophthalmol 121: 785-92. Van de Leun, J. 1996.