Age-related macular degeneration (AMD) is a deterioration or breakdown of the central retina, also called the macula. The macula is a small area in the retina – the light-sensitive tissue lining the back of the eye. The macula is the part of the retina that is responsible for your central vision, allowing you to see fine details clearly.
Many older people develop macular degeneration as part of the body’s natural aging process. There are different kinds of macular degeneration, but the most common is age-related macular degeneration. This degeneration is described as either dry or wet.
With macular degeneration, you may have symptoms such as blurriness, dark areas or distortion in your central vision, and perhaps permanent loss of your central vision. For example, with advanced macular degeneration, you could see the outline of a clock, yet may not be able to see the hands of the clock to tell what time it is.
Causes and Impact
Causes of macular degeneration include the formation of deposits called drusen under the retina (the dry type and the most common) and in some cases, the growth of abnormal blood vessels under the retina (the wet type). With or without treatment, macular degeneration alone almost never causes total blindness. People with more advanced cases of macular degeneration continue to have useful vision using their side or peripheral vision.
When macular degeneration does lead to loss of vision, it usually begins in just one eye, though it may affect the other eye later. Many people are not aware that they have macular degeneration until they have a noticeable vision problem or until it is detected during an eye examination.
Unfortunately, at this time there is no single proven treatment for the dry form of macular degeneration. However, a large scientific study has shown that antioxidant vitamins and zinc may reduce the impact of macular degeneration in some people by slowing its progression toward more advanced stages.
The Age-Related Eye Disease Study (AREDS) showed that among people at high risk for developing late-stage, or wet, macular degeneration (such as those who have large amounts of drusen or who have significant vision loss in at least one eye), taking a dietary supplement of vitamin C, vitamin E and beta carotene, along with zinc, lowered the risk of the progression of macular degeneration by about 25 percent. The supplements did not appear to provide a benefit for people with minimal macular degeneration or normal retinas.
Following is the nutrient supplementation shown to be beneficial based on the AREDS study:
- Vitamin C – 500 mg
- Vitamin E – 400 IU
- Beta carotene – 15 mg (25,000 IU)
- Zinc oxide – 80 mg
- Copper (as cupric oxide) – 2 mg (to prevent copper deficiency, which may be associated with taking high amounts of zinc)
A large study in women only, showed a benefit from taking folic acid and vitamins B6 and B12. A large study evaluating the possible benefits of lutein and fish oil (omega-3) is ongoing. Other studies have shown that eating dark leafy greens, and yellow, orange and other colorful fruits and vegetables, rich in lutein and zeaxanthin, may reduce your risk for developing macular degeneration.
These vitamins and minerals are recommended in specific daily amounts, in addition to a healthy, balanced diet. Some people may not want to take large doses of antioxidants or zinc because of medical reasons. Beta carotene has been shown to increase the risk of lung cancer in smokers or recent past smokers, so this supplement should not be used by people who currently smoke or recently quit smoking.
Treatment of the wet form of macular degeneration has improved dramatically with the use of anti-VEGF medications and painless injections into the eye with Avastim, Lucentis or Eylea now a mainstay of treatment.