The retina, the innermost layer of the eye, receives all images and sends them to the brain. The macula is a yellow spot in the retina at the back of the eye that is needed to see objects in great detail. Macular degeneration is an eye disease that can result in blurry, distorted vision and eventual vision loss. Part of the treatment involves antioxidants, but calcium is not an antioxidant.
What is Macular Degeneration?
Macular degeneration is the number one cause of painless vision loss within the elderly population, according to Jonathan Horton, M.D., Ph.D., Professor of Neuro-Ophthalmology at the University of California, San Francisco, and author of a chapter on eye disorders in "Harrison's Principles of Internal Medicine." There are two types of this disease: wet and dry. Permanent vision loss of both eyes is a potential symptom of both types. Most people have the dry type, where blood vessels underneath the macula at the back of the eye get brittle and thin. In the wet type, the blood vessels break down and abnormal blood vessels form.
What Causes This Disease?
Scientists are not yet sure what causes macular degeneration, according to Bertram Katzung, M.D., Ph.D., Professor Emeritus in the Department of Cellular and Molecular Pharmacology at the University of California and one of the authors of "Basic & Clinical Pharmacology." Dr. Katzung and his colleagues have identified several risk factors for macular degeneration, including cigarette smoking, age, obesity, high blood pressure, genetics, cardiovascular disease, being female and having a low level of antioxidants. In fact, antioxidants are not only used to delay the development of macular degeneration, they are even used to try to prevent it. Calcium, however, is not an antioxidant.
Antioxidants
Physicians advise that people raise their level of antioxidants by taking 15 mg of beta-carotene, 500 mg of vitamin C, 80 mg of zinc oxide, 400 IU of vitamin E and 2 mg of copper every day, writes Sunir Garg, M.D., Assistant Professor of Ophthalmology at Thomas Jefferson University in "The Merck Manual for Healthcare Professionals." People can take 25,000 IU of vitamin A instead of taking beta-carotene, but beta-carotene and vitamin A have been found to create an increased risk of developing lung cancer in people who smoke cigarettes. Therefore, physicians do not advise that people take either of these two supplements if they have smoked within seven years of developing macular degeneration.
Antioxidants or Calcium?
Since calcium is not an antioxidant, it is not part of the recommended treatment for macular degeneration, although calcium and vitamin D are vital for the development and maintenance of strong, healthy bones. The National Eye Institute of the National Institutes of Health sponsored a large clinical trial, known as the Age-Related Eye Disease Study, AREDS, in which the researchers demonstrated that taking antioxidants at the above-mentioned levels, not calcium, can reduce the risk of developing age-related macular degeneration by 25 percent. They also warn that daily multivitamins will not have the desired antioxidant levels, and the use of all vitamins should be reviewed with the physician.
References
- "Basic & Clinical Pharmacology"; Bertram Katzung, M.D., Ph.D., Susan Masters, Ph.D., Anthony Trevor, Ph.D.; 2009
- "Harrison's Principles of Internal Medicine"; Anthony Fauci, M.D., Dennis Kasper, M.D., Dan Longo, M.D., et al.; 2008
- National Institutes of Health: Facts About Age-Related Macular Degeneration
- The Merck Manual for Healthcare Professionals: Age-Related Macular Degeneration (AMD or ARMD)
