A Simplified Severity Scale for Age-Related Macular Degeneration. AREDS Report No. 18
Year of Publication
Ferris, F; Davis, M; Clemons, T; Lee, L; Chew, E; Lindblad, A; Milton, R; Bressler, S; Klein, R; Age-Related Eye Disease Study (AREDS) Research Group
Disease Progression; Macular Degeneration; Photography; Retinal Drusen; Retinitis Pigmentosa; Risk Factors; Severity of Illness Index
OBJECTIVE: To develop a simplified clinical scale defining risk categories for development of advanced age-related macular degeneration (AMD). METHODS: Following development of a detailed scale for individual eyes based on gradings of fundus photographs in the Age-Related Eye Disease Study, rates of progression to advanced AMD were assessed in cross-tabulations of presence or absence in each eye of 2 easily identified retinal abnormalities, drusen and pigment abnormalities. Large drusen and any pigment changes were particularly predictive of developing advanced AMD. RESULTS: The scoring system developed for patients assigns to each eye 1 risk factor for the presence of 1 or more large (> or = 125 microm, width of a large vein at disc margin) drusen and 1 risk factor for the presence of any pigment abnormality. Risk factors are summed across both eyes, yielding a 5-step scale (0-4) on which the approximate 5-year risk of developing advanced AMD in at least one eye increases in this easily remembered sequence: 0 factors, 0.5%; 1 factor, 3%; 2 factors, 12%; 3 factors, 25%; and 4 factors, 50%. For persons with no large drusen, presence of intermediate drusen in both eyes is counted as 1 risk factor. CONCLUSION: This simplified scale provides convenient risk categories for development of advanced AMD that can be determined by clinical examination or by less demanding photographic procedures than used in the Age-Related Eye Disease Study.