Purpose: Recent structural and histochemical data from our laboratory indicate that human drusen often possess distinct, structural core domains. A similar, corelike structure is frequently noted clinically in some drusen-related conditions. To assess the nature of the corelike structures observed clinically, we evaluated color photographs and fluorescein angiograms from patients with early-adult onset grouped drusen (EAOGD).
Design: Retrospective case series.
Methods: The areas of the six largest drusen and hyperfluorescent lesions for eight patients confirmed to have EAOGD were estimated by two masked examiners (RRG, JCF). Data were normalized using a logarithmic transformation and evaluated using a mixed model analysis to account for intragrader, interobserver and intrasubject effects.
Results: The average color to hyperfluorescence drusen area ratio was 2.29 (SE, 0.06). The area of drusen viewed in color photographs significantly exceeds that of the corresponding area of hyperfluorescence (P <.0001). The average drusen area (geometric mean) was 0.014 mm(2) (SE, 0.001 mm(2)) and the average hyperfluorescent lesion area was 0.006 mm(2) (SE, 0.0005 mm(2)). The areas of the hyperfluorescent lesions do not vary among the capillary, venous, and washout angiographic phases. The lesions exceed choroidal intensity and demonstrate prominent, uniformly hyperintense fluorescence throughout all but the choroidal phases of the angiogram.
Conclusions: These data show that large visible drusen in EAOGD are concentric to regions of hyperfluorescence, suggesting that drusen may possess clinically detectable, substructural domains. Ongoing studies seek to determine whether clinical evidence of drusen substructure may exist in other drusen-associated disorders, such as in age-related macular degeneration.