is a disease that damages the eyes and causes vision loss. It is often referred to as age-related or adult macular degeneration (AMD). It is a common, leading cause of severe visual impairment in Americans; it affects almost a third of people over the age of 75 . There is no cure for AMD, and treatment is somewhat limited.
The macula is the central part of the retina of the eye that makes it possible to see the fine detail needed for reading, driving, and recognizing faces. AMD causes the macula to malfunction or deteriorate. The result is loss of sight in the center of the visual field; fortunately, peripheral vision is rarely affected.
Most cases of AMD are due to a combination of genetic and environmental factors. Some risk factors include:
Age: risk increases with age, most commonly seen in senior citizens
Family members with AMD
Heavy alcohol use
Exposure to sunlight
Any factor that increases the presence of free radicals also increases risk for macular degeneration. Free radicals are naturally produced when your body processes food for energy. They can also result from other stresses on the body, such as exposure to ultraviolet rays of the sun, smoking, and environmental pollution. Free radicals are unstable molecules that may cause damage to DNA and other molecules. Over time, this damage may lead to AMD or many other diseases, such as cancer.
In addition, any factor that undermines the circulatory system increases risk for macular degeneration. The macula needs a rich blood supply. Therefore, any interference with it, such as smoking or a sedentary lifestyle, can increase risk of AMD.
Nutritional supplements and antioxidants
in particular, have been the focus of much research on the prevention of AMD. Antioxidants are thought to protect cells—in the eye and elsewhere—from free radical damage. High levels of antioxidants are found naturally in fruits and vegetables, as well as in other foods including egg yolks; nuts and grains; and some meats, poultry, and fish. They can also be concentrated in supplements.
Though the benefits of supplementation are often extolled in the media, recent clinical studies have had inconsistent results. While some studies reveal a link between higher levels of antioxidants and lower risk of AMD, many do not. Antioxidants that have been shown to protect the macula in research studies include vitamin C, vitamin E, zinc, beta-carotene, and flavonoids.
Mixture of Zinc and Antioxidants
For example, a major clinical study sponsored by the National Institutes of Health was designed to determine whether high levels of antioxidants and zinc could reduce the risk of developing advanced macular degeneration. For six years, researchers followed 3,600 people with varying stages of AMD. The results showed that high doses of vitamin E, vitamin C, beta carotene, and zinc lowered their risk of developing advanced AMD by 25%. The supplements did not seem to have any effect on people with no evidence of the disease or very early stages of the disease.
Two lesser known carotenoids—lutein and zeaxanthin—are present in a concentrated area in the macula itself. Theoretically, in addition to preventing AMD by reducing the damaging effects of free radicals, these antioxidants are thought to prevent AMD by protecting the eye against the damaging effects of ultraviolet and blue light. Lutein and zeaxanthin are found mostly in green leafy vegetables and corn.
Flavanoids, found in high levels in tea and red wine, may be particularly helpful because they act as powerful antioxidants and also thin the blood, improving circulation.
Living a Healthful Lifestyle
The following recommendations for a healthful lifestyle apply to those with AMD and those who are at risk of developing the disease:
Although scientific evidence is inconclusive, a diet rich in nutrients may lower your risk of AMD. Try to ingest a high level of antioxidants by eating at least five servings a day of varied fruits and vegetables. Green leafy vegetables such as spinach, kale, and collard greens are particularly recommended. Eating fish and other foods that contain omega-3 fatty acid may also reduce your risk of getting AMD. Also moderate wine consumption may help decrease the risk of developing AMD.
Engage in Regular Physical Exercise
Cardiovascular exercise improves the body’s overall health and helps maintain a healthy circulatory system.
Reduce Sun Exposure
Always wear a hat or cap when outdoors, and wear sunglasses or protective lenses all year.
See Your Doctor…
To treat hypertension, high cholesterol, or other heart-related conditions
For regular eye exams—once every other year before age 50, and every year after that
Adult macular degeneration. Macular Degeneration Partnership website. Available at:
http://www.amd.org. Accessed October 9, 2005.
Antioxidant vitamins and zinc reduce risk of vision loss from age-related macular degeneration. National Eye Institute, Press Release (October 12, 2001). Available at:
http://www.nei.nih.gov/amd. Accessed October 9, 2005.
The AREDS formulation and age-related macular degeneration: are these high levels of antioxidants and zinc right for you? National Eye Institute, Press Release (October 12, 2001). Available at:
http://www.nei.nih.gov. Accessed October 9, 2005.
Basic anatomy of a normal human eye. The American Macular Degeneration Foundation website. Available at:
. Accessed October 9, 2005.
Beers MH, Fletcher AJ, Jones TV, et al. The Merck Manual of Medical Information. Second Home Edition. Merck Research Laboratories: Whitehouse Station, NJ; 2003.
“Dry” macular degeneration. The American Macular Degeneration Foundation website. Available at:
http://www.macular.org. Accessed October 9, 2005.
Frequently asked questions. Adult macular degeneration. MD Foundation, Inc. Available at:
http://www.eyesight.org. Accessed October 9, 2005.
Macular degeneration. American Academy of Ophthalmology. Available at:
http://www.aao.org. Accessed October 9, 2005.
Please be aware that this information is provided to supplement the care
provided by your physician. It is neither intended nor implied to be a
substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER
IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the
advice of your physician or other qualified health provider prior to
starting any new treatment or with any questions you may have regarding a