Abstract
Purpose: :
To describe the 15–year cumulative incidence of retinal drusen, retinal pigmentary abnormalities (PA), and signs of late age–related macular degeneration (AMD) in a population–based study.
Methods: :
4,926 persons, 43–86 years of age at the time of a baseline examination in 1988–1990, living in Beaver Dam, Wisconsin, of whom 3,684, 2,764, and 2,119 participated in 5–, 10–, and 15–year follow–up examinations, respectively. Characteristics of drusen and other lesions typical of AMD were determined by grading stereoscopic color fundus photographs using the Wisconsin Age–Related Maculopathy Grading System.
Results: :
The 15–year incidence in either eye of early AMD was 16.6% and for late AMD it was 3.9%. There was a statistically significant increased incidence of AMD lesions with age (p<0.001). Individuals 75 years of age or older at baseline had significantly (p<0.001) higher 15–year incidences of the following AMD characteristics than persons 43 to 54 years of age: larger sized drusen (≥ 125 µm in diameter, 66.2% vs. 11.0%), soft indistinct drusen (45.9% vs. 6.8%), pigmentary abnormalities (PA) (44.9% vs. 3.8%), exudative AMD (9.3% vs. 0.4%), and pure geographic atrophy (9.9% vs. 0%). Compared to right eyes with few small hard drusen at baseline (estimated 1 to 2), those with many small hard drusen (estimated 8 or greater) had an increased 15–year incidence of both soft indistinct drusen (18.3% vs. 4.7%) and PA (10.9% versus 3.2%). Eyes with soft indistinct drusen or PA at baseline were more likely to develop late AMD at follow–up than eyes without these lesions (28.1% vs. 1.3% and 19.6% vs. 1.8%, respectively).
Conclusions: :
These population–based estimates document the high long–term incidence of signs of AMD and a continuum from small hard drusen to late AMD in older persons in the population. The 20% cumulative incidence of late AMD in people 75 years of age or older indicates a public health problem of significant proportions as it is expected that those in the United States population this age will increase by 54% from 18 million in the year 2005 to 28 million people by the year 2025.
Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: natural history • clinical (human) or epidemiologic studies: prevalence/incidence