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Susan Vitale, Traci E Clemons, Elvira Agron, Frederick L Ferris, Amitha Domalpally, Ronald P Danis, Emily Y Chew, AREDS2 Research Group; Evaluating the AREDS grading scale for age-related macular degeneration in AREDS2. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):3794.
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© ARVO (1962-2015); The Authors (2016-present)
To compare 5-year rates of development of late age-related macular degeneration (AMD) between the AREDS and AREDS2 studies, using the AREDS severity scale for AMD.
The severity scale for AMD is based on stereoscopic color fundus photograph gradings developed by using study data from the AREDS clinical trial, which compared the risk of late AMD for placebo versus high-dose antioxidants and/or zinc. Photos were graded for drusen characteristics (size, area), pigmentary abnormalities (hyper- or hypopigmentation or geographic atrophy (GA)), and signs of neovascular AMD (nvAMD). Risk of development of late AMD (nvAMD, central GA, or treatment for AMD) within 5 years increased with each additional step on the scale in AREDS participants. In AREDS2, participants at high risk of developing late AMD were recruited for a second, separate clinical trial of nutritional supplements for AMD. Stereo color fundus photographs were obtained yearly for AREDS2 participants and graded by masked graders using protocols developed for AREDS. The severity scale was computed for each AREDS2 participant at baseline and 5-year rates of late AMD were computed for each step of the scale, starting at step 4, the minimal AMD severity recruited into AREDS2. One eye per participant was designated as the study eye (free of late AMD) for analyses.
2719 AREDS2 participants (aged 50-86 y (mean, 72 y), 58% female) were free of late AMD in both eyes at baseline. At baseline, 97.9% of study eyes had drusen area ≥ area of a 125-μm-diameter circle (.0069 disc area), 98.2% had ≥ 1 intermediate-sized druse, and 93.0% had ≥ 1 large druse. At baseline, 56.5% of study eyes had increased pigmentation, 21.8% had depigmentation or noncentral GA, and 59.2% had ≥ 1 type of retinal pigment epithelial abnormality. The rates of progression to late AMD in AREDS and AREDS2 by the AREDS AMD scale are compared in the Figure.<br /> The differences in the rates of progression to late AMD between AREDS and AREDS2 may be explained by the fact that all AREDS2 participants received a form of antioxidant plus zinc, while the AREDS population included two treatment arms that did not include both antioxidants and zinc (AREDS supplements).
The AREDS severity scale for AMD appears to perform comparably in the AREDS2 data. The scale will be a useful tool for characterizing risk of late AMD.
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