Fluorescence characteristics of drusen during indocyanine-green angiography and their possible correlation with choroidal perfusion

Abstract

The fluorescence of drusen and their correlation with choroidal perfusion was investigated using indocyanine-green videoangiography in 37 patients (mean age, 66 +/- 16 years) with juvenile and senile drusen. Most senile drusen (89%) blocked choroidal indocyanine-green fluorescence, and only three patients had small, weakly hyperfluorescent drusen at the vascular arcade. In contrast, all juvenile drusen (patients aged 31-52 years) demonstrated strong hyperfluorescence. Impaired choroidal perfusion was not detected. In 33% of the patients, all of them older than 60 years, moderate choroidal hypofluorescence could be explained by the presence of confluent drusen and/or a thickening of the pigment epithelium-Bruch's membrane complex. The results of the present study demonstrate that indocyanine-green angiography enables the differentiation of juvenile drusen from senile drusen, which could be an indication of a differing pathogenesis for the two diseases. Indocyanine-green hyperfluorescence of drusen must be caused by the transmission of choroidal fluoresence. This jeopardizes the hypothesis that the fluorescein fluorescence of drusen is invariably caused by storage of the dye. Our results contradict previous fluorescein studies that have demonstrated impaired choroidal perfusion in patients with age-related macular degeneration.