Abstract
We tested the hypothesis that large areas of small hard drusen (diameter <63 μm) and intermediate drusen (diameter 63-124 μm) are associated with the incidence of age-related macular degeneration (AMD). Eyes of 3344 older adults with at least 2 consecutive visits spaced 5 years apart over a 20-year period were included. A 6-level severity scale including no drusen, 4 levels of increasing area (from minimal [<2596 μm(2)] to large [>9086 μm(2)]) of only small hard drusen, and intermediate drusen was used. The 5-year incidence of AMD was 3% in eyes at the start of the interval with no, minimal, small, and moderate areas of only small drusen and 5% and 25% for eyes with large area of only small drusen and intermediate drusen, respectively. Compared to eyes with a moderate area of small drusen, the odds ratio (OR) of developing AMD in eyes with a large area of only small drusen was 1.8 (P<.001). Compared to eyes with large area of only small drusen, eyes with intermediate drusen had an OR of 5.5 (P<0.001) of developing AMD. Our results are consistent with our hypothesis that large areas of only small drusen are associated with the incidence of AMD.