Macular degeneration 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 cause of severe visual impairment in Americans. It affects about 30% 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.
Most cases of AMD are due to a combination of genetic and environmental factors. Some risk factors include:
- Age: Older adults have an increased risk.
- Family members with AMD
- Race: White or Asian
- Excessive exposure to sunlight
- Gender: Women have an increased risk.
Any factor that increases the presence of free radicals may also increase the 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 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, may increase risk of AMD.
Nutritional supplements 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 (like egg yolks, nuts, grains, and some meats). They can also be concentrated in supplements.
Though the benefits of supplementation are often extolled in the media, 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.
The antioxidants that have shown promise include vitamin C, vitamin E, zinc, beta-carotene, and flavonoids. 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 in patients who already had 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.
Researchers have also investigated the role carotenoids may have in AMD. Carotenoids are another substance found in fruits and veggies (especially corn and dark green leafy vegetables). Some observational studies have shown a link between diets high in cartenoids and lower rates of macular degeneration. However not all studies have shown this link. Also, a 12-month trial found that people with AMD who took lutein (either alone or paired with other supplements) had an improvement in their vision compared to those who took a placebo.
Living a Healthy Lifestyle
The following recommendations for a healthy lifestyle apply to those with AMD and those who are at risk of developing the disease:
- Eat right.—Although the evidence is inconclusive, a diet rich in nutrients may lower your risk of AMD. Try to include antioxidants in your diet by eating a variety of 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 acids may also help to lower your risk of AMD.
- Exercise regularly.—Cardiovascular exercise improves the body’s overall health and helps maintain a healthy circulatory system.
- Reduce sun exposure.—Always wear a hat when outdoors, and wear sunglasses or protective lenses all year.
- See your Doctor.—If you have a chronic condition, get proper treatment. Also make sure that you have your eyes examined on a regular basis. Lastly, if you are planning on taking a supplement, talk to your doctor first.
- Reviewer: Brian Randall, MD
- Review Date: 12/2011 -
- Update Date: 03/11/2013 -