A study of individuals with age-related macular degeneration (AMD), based at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, found that nearly 40 percent of those likely to benefit from specific vitamin/mineral supplements were either not taking the supplements or not using the recommended dosage. The study also showed that some patients used high-dose supplements even in the absence of evidence that these would be effective for their levels of AMD or other eye conditions.
The ophthalmic researchers, led by Susan B. Bressler, M.D., concluded that AMD patients appear to lack a clear understanding of supplement use in AMD treatment, and that "improved patient education may be vital to maximize the potential" of this therapy.
The public health impact could be substantial: in the United States if the appropriate patients used the correct supplements, about 300,000 people could potentially avoid advanced AMD within a five year period. At least eight million Americans are at risk for advanced AMD which can destroy the central vision needed to recognize faces, read, drive and enjoy daily life. In 2001 the Age-Related Eye Disease Study (AREDS) reported findings on its clinical trial that identified a specific formula of antioxidants (vitamin C, vitamin E and beta-carotene) and zinc that reduced the probability of progression to advanced AMD by 25 percent-- either the "wet" or central geographic atrophy forms---among individuals at risk.
Those who have AMD and smoke may need to use a formula that omits beta-carotene since high doses of this micronutrient have been associated with increased rates of lung cancer and mortality. Though effective treatment for advanced AMD is available, it can be expensive and is limited to the "wet" form. Also, since such treatment may not restore vision already lost to the illness, it remains important to use all effective approaches to preventing AMD progression.
The Wilmer Institute-based study surveyed 332 individuals who identified themselves as having AMD; the median participant age was 79 years. Of these, 228 were considered candidates for benefit from the AREDS formula, but only 140 patients (61 percent) in this group were using the correct formula as recommended. Nearly 50 percent of the candidates-for-benefit did not correctly answer questions on the relevance of vitamin/mineral supplements to their eye condition and how their vision might benefit. But patients who indicated that they partially or fully understood the rationale for supplements were about twice as likely to be using the AREDS formula correctly.
This research was published in the June 2008 issue of Ophthalmology.
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