The grading and prevalence of macular degeneration in Chesapeake Bay watermen.

A new grading scheme was developed to classify the fundus features of macular degeneration. This scheme identifies the earliest fundus changes associated with macular degeneration, as well as specific drusen characteristics felt to be associated with an increased risk of developing the exudative forms of this disease. Agreement between two graders using this scheme indicated good interobserver reliability. Using this scheme, fundus photographs of 777 participants were graded in a population-based study of watermen from the eastern shore of Maryland. The prevalence of at least one druse within 1500 microns of the foveal center was extremely common (over 80% in each age group over 30 years of age) and not age related. The prevalence of large, confluent, or soft drusen was relatively uncommon and was age related; by the eighth decade, 26% of all participants had large or soft drusen, and 17% of them had confluent drusen. These latter characteristics are more likely to be markers of early changes consistent with age-related macular degeneration rather than simply the presence of a few drusen.