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AMD and Blue light exposureCreated October 13, 2008Because a combination of low plasma levels of antioxidants and blue light exposure from the sun is associated with certain forms of age-related macular degeneration (AMD), increasing intake of antioxidants may protect the eyes, according to the results of a study reported in the October issue of the Archives of Ophthalmology."Animal and laboratory studies have shown that blue light damages the retinal pigment epithelium and choriocapillaris through generation of reactive oxygen species and may be a factor in the pathogenesis of...AMD," write Astrid E. Fletcher, PhD, from London School of Hygiene & Tropical Medicine, London, United Kingdom, and colleagues. "Protection against the harmful effects of blue light is provided by the retinal antioxidant defense system, which includes antioxidant enzymes supported by vitamins C and E, the carotenoids (lutein and zeaxanthin), and zinc." The goal of this study was to determine the relationship between sunlight exposure and antioxidant level with AMD in 4753 participants, aged 65 years or older, enrolled in the European Eye Study. These participants underwent fundus photography and blood drawing for antioxidant analysis and were interviewed for adult lifetime sunlight exposure. Meteorologic and questionnaire data were combined to estimate blue light exposure. Data on sunlight exposure and antioxidants were available for 101 participants with neovascular AMD, 2182 with early AMD, and 2117 control subjects. There was no association between blue light exposure and neovascular AMD or early AMD. In participants in the lowest quartile of antioxidant level (vitamin C, zeaxanthin, vitamin E, and dietary zinc), there were significant associations between blue light exposure and neovascular AMD. Odds ratio (OR) was approximately 1.4 for 1 SD unit increase in blue light exposure, but these ORs for blue light were higher with combined low antioxidant levels, especially vitamin C, zeaxanthin, and vitamin E (OR, 3.7; 95% confidence interval [CI], 1.6 - 8.9), which were also associated with early stages of AMD. Limitations of this study include lack of information on genetic factors in the European Eye Study. "Although it is not possible to establish causality between sunlight exposure and neovascular AMD, our results suggest that people in the general population should use ocular protection and follow dietary recommendations for the key antioxidant nutrients," the study authors write. "In the absence of cost-effective screening methods to identify people in the population with early AMD, we suggest that recommendations on ocular protection and diet target the general population, especially middle-aged people." The European Eye Study was supported by the European Commission Vth Framework. The Macular Disease Society provided additional funding for cameras. The Alicante site was supported by the Spanish Ministry of Health; Centro de Investigación Biomédica en Red de Epidemiologiá y Salud Pública; and by the Generalitat Valenciana. Some of the study authors have disclosed various financial relationships with Alcon, Bausch & Lomb, and/or the Estonian Ministry of Education and Science. The other study authors have disclosed no relevant financial relationships. Arch Ophthalmol. 2008;126:1396-1403. Clinical ContextWavelengths in the UV radiation range are largely absorbed by the cornea and lens, but the retina is exposed to visible light, including blue light. The retina becomes vulnerable to damage, which may play a role in the pathogenesis of AMD. Protection against the dangerous effects of blue light is provided by the retinal antioxidant defense system, which includes antioxidant enzymes supported by vitamins C and E, the carotenoids (lutein and zeaxanthin), and zinc. Specifically, the carotenoids act as scavengers of reactive oxygen species and filter blue light. Currently, limited evidence is known regarding the possible interactions between antioxidant levels and light exposure with the development of AMD.The aim of this study was to examine the association of sunlight exposure and antioxidant level with AMD. Study Highlights
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