Analysis of the Relationship Between Drusen Size and Drusen Area in Eyes With Age-Related Macular Degeneration

BACKGROUND AND OBJECTIVE: To examine the relationship between drusen counts and drusen area in eyes with age-related macular degeneration, and to correlate drusen areas between fellow eyes. PATIENTS AND METHODS: Digital images from 378 patients (756 eyes) were analyzed using a validated drusen detection algorithm. Total drusen area and the number of drusen of various sizes (small: < 62 microns, intermediate: 63–124 microns, large: 125–249 microns, etc) were recorded for the central 1,000- and 3,000-micron diameter macular regions. Correlations were assessed using structural equation models. RESULTS: For the 1,000-micron region, the number of intermediate drusen was more highly correlated to total drusen area than the number of large drusen (R = 0.91 vs 0.82); this difference was statistically significant. The correlation coefficients for drusen area between fellow eyes was 0.73. CONCLUSION: The number of large drusen does not correlate better with total drusen area than drusen of other sizes. The number of large drusen is not necessarily a good surrogate for total drusen area.