Purpose: To evaluate differences in fluorescein angiography (FA) and indocyanine green angiography (ICGA), findings between subjects affected by Stargardt disease (STGD) and atrophic AMD.
Methods: This was a consecutive, cross-sectional case series. A total of 24 eyes of 12 patients with STGD and 23 eyes of 14 patients with atrophic AMD were enrolled in the study. Patients underwent dynamic simultaneous FA and ICGA using a dual beam confocal scanning system. Images were recorded from the initial filling of choroidal and retinal vessels throughout all the phases of the angiogram. Spectral-domain optical coherence tomography (SD-OCT) and fundus autofluorescence were also executed. FA and ICGA findings in the two groups were evaluated.
Results: In 92% (22/24) of eyes affected by STGD, ICGA showed hypocyanescence from the areas of atrophy, more evident in the late phases. This finding, defined as ICGA-imaged "dark atrophy," was present in only 13% (3/23) of the eyes affected by atrophic AMD. The remaining eyes in both groups showed iso- or mild hypercyanescence from the areas of atrophy. Eyes with ICGA-imaged dark atrophy, both in STGD and in atrophic AMD groups, did not show early obscuration of the choroidal vessels by FA. SD-OCT revealed morphologically intact choroid in STGD patients with ICGA-imaged dark atrophy. In atrophic AMD eyes with ICGA-imaged dark atrophy, SD-OCT revealed a severely thinned choroid.
Conclusions: Hypocyanescence by ICGA from the areas of atrophy was more frequent in STGD compared with atrophic AMD. This finding, along with SD-OCT evidence of intact choroid, suggests a possible selective damage of the choriocapillaris in STGD.