It has been known for a long time that certain vitamins are important for eye health. With the population steadily aging and the risk of age-related eye conditions such as cataracts and macular degeneration increasing, today's research focuses more than ever on whether and which dietary supplements play a role in preserving vision.
Basic Anatomy of Eye
Having good vision depends on how the eye transfers light, which enters first through the cornea, the front of the eye, then through the iris, the colored part of the eye. The lens sits behind the iris and is essential in transmitting light rays to the retina at the back of the eye. The retina is a nervous tissue membrane that lines the back of the eye. The cells of the retina convert the light from images into a neurological signal that travels via the optic nerve to the brain, where it is interpreted as vision. At the center of the retina, you'll find a small yellow spot called the macula, which is responsible for high-acuity vision, allowing you to see details clearly.
Eye Conditions
The most common eye conditions are cataracts and age-related macular degeneration, or ARMD. The risk of developing these conditions increases with age. It is estimated that more than 70 percent of people over the age of 75 suffer from cataracts. Cataracts are characterized by a progressive loss of transparency in the lens of the eye, resulting in blurry and cloudy vision. Age-related macular degeneration is caused by deterioration of the macula and is one of the leading causes of vision loss in the Western world. According to data supplied by the Macular Degeneration Support website, this disease affects approximately 8.5 million people in the U.S. today. Macular degeneration reduces your vision in the central part of the retina, eventually leaving you with peripheral vision only.
Prevention
According to Dr. Andrew Weil, clinical professor of medicine at the University of Arizona and director of its Program in Integrative Medicine, the occurrence of cataracts and ARMD might be delayed by quitting smoking, protecting your eyes from ultraviolet, or UV, rays, and adhering to a healthy diet that includes plenty of foods that are high in antioxidants such as lutein and zeaxanthin. These compounds, members of the carotenoid family, form the yellow pigment in the macula and play an important role in eye health: They filter out blue light, a harmful component of sunlight. As antioxidants and anti-inflammatory agents, they protect the eye from oxidative damage caused by UV rays. Lutein and zeaxanthin are found in egg yolks, green leafy vegetables, peas and summer squash. Other foods that are important for preserving vision are foods high in omega-3 fatty acids, such as salmon, sardines, flaxseed and walnuts. Omega-3 fatty acids have anti-inflammatory properties that help protect the cells of the retina from cell death. Whether foods containing lutein, zeaxanthin and omega-3 fatty acids or supplements will protect you from developing cataracts or ARMD, or will delay their occurrence or progression, is at the moment the subject of research. Until it has been scientifically proven that your eyes will benefit from taking these supplements, the recommendation is to adhere to a healthy diet full of fruits and vegetables and foods high in omega-3 fatty acids.
Research
One of the few studies that has shown a clear benefit from supplements is the Age-Related Eye Disease Study, or AREDS. This major trial sponsored by the National Eye Institute and published in the "Archives of Ophthalmology" in October 2001 showed that a supplement containing 500 mg of vitamin C, 400 IU of vitamin E, 15 mg of beta-carotene (vitamin A), 80 mg of zinc and 2 mg of copper slowed down ARMD by about 25 percent. No such benefit was seen in patients with cataracts. The second Age-Related Eye Disease Study, or AREDS2, is presently being conducted. The purpose of the second study, which started in September 2006 and will be completed in December 2012, is the following: to evaluate the effect on the progression of ARMD and cataracts by lutein, zeaxanthin and omega-3 fatty acids and to evaluate the effect of eliminating beta-carotene and reducing the amount of zinc used in the first study. Concerns about the effect of high dosages of beta-carotene and zinc have led to the elimination of the former and a reduced dosage of the latter in AREDS2.
Warning
The formulation used in AREDS1 has been shown to be beneficial only in a certain subgroup of patients with ARMD. If you are currently suffering from ARMD and would like to know whether this combination of supplements would work for you, please consult your ophthalmologist first.
References
- "Archives of Ophthalmology"; "A Randomized, Placebo-Controlled, Clinical Trial of High-Dose Supplementation With Vitamins C and E, Beta Carotene, and Zinc for Age-Related Macular Degeneration and Vision Loss"; Age-Related Eye Disease Study Research Group; October 2001
- "Archives of Ophthalmology"; "Doctor, What Vitamins Should I Take for My Eyes?"; Julie Mares et al; April 2004
- "International Ophthalmology"; "Prevention of age-related macular degeneration"; Ian Yat Hin Wong et al; February 2011
