Indocyanine green angiography and occult choroidal neovascularization

To evaluate the use of digital indocyanine green (ICG) angiography as an adjunct to fluorescein angiography in the diagnosis and treatment of ill-defined choroidal neovascularization (CNV) associated with age-related macular degeneration (AMD).

The authors retrospectively reviewed all ICG angiograms performed at Wills Eye Hospital from March to July 1992. Included in this study were all cases with exudative 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 follow-up.

Of the 101 eligible cases, ICG angiography at presentation demonstrated well-defined hyperfluorescence in 40 cases (group 1), ill-defined hyperfluorescence in 43 cases (group 2), mixed pattern of well- and ill-defined hyperfluorescence in 14 cases (group 3), and 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 solely on ICG angiogram findings was performed in 19 group 1 cases (extrafoveal hyperfluorescent foci only) and in 8 group 3 cases, with treatment in both groups being directed only to areas of well-defined hyperfluorescence. Successful treatment was achieved in 12 (63%) of 19 cases and in 2 (25%) of 8 cases, respectively. There was a strong correlation between post-treatment persistence or recurrence of ICG hyperfluorescence and treatment failure.

Indocyanine green angiography is a valuable diagnostic adjunct to fluorescein angiography in evaluating 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 promising in this subgroup.