INDOCYANINE GREEN ANGIOGRAPHY AND OCCULT CHOROIDAL NEOVASCULARIZATION

Purpose: To evaluate the use of digital indocyanine green (ICG) angiog raphy as an adjunct to fluorescein angiography in the diagnosis and tr eatment of ill-defined choroidal neovascularization (CNV) associated w ith age-related macular degeneration (AMD). Methods: The authors retro spectively reviewed all ICG angiograms performed at Wills Eye Hospital from March to July 1992. Included in this study were all cases with e xudative manifestations of AMD in which fluorescein angiography showed ill-defined CNV. The initial ICG findings and the clinical outcome of both treated and untreated cases were evaluated through 6 months of f ollow-up. Results: Of the 101 eligible cases, ICG angiography at prese ntation demonstrated well-defined hyperfluorescence in 40 cases (group 1), ill-defined hyperfluorescence in 43 cases (group 2), mixed patter n of well- and ill-defined hyperfluorescence in 14 cases (group 3), an d no abnormalities in 4 cases (group 4). Approximately one half of the cases with well-defined ICG hyperfluorescence (21% of the total) had only extrafoveal changes. Laser photocoagulation treatment based solel y on ICG angiogram findings was performed in 19 group 1 cases (extrafo veal hyperfluorescent foci only) and in 8 group 3 cases, with treatmen t in both groups being directed only to areas of well-defined hyperflu orescence. Successful treatment was achieved in 12 (63%) of 19 cases a nd in 2 (25%) of 8 cases, respectively. There was a strong correlation between post-treatment persistence or recurrence of ICG hyperfluoresc ence and treatment failure. Conclusions: Indocyanine green angiography is a valuable diagnostic adjunct to fluorescein angiography in evalua ting occult CNV in AMD. In this series, well-defined, extrafoveal ICG hyperfluorescence was identified in 21% of the cases, and preliminary, short-term results suggest that ICG-guided laser treatment is promisi ng in this subgroup.