Purpose: This study aimed to determine whether indocyanine green (ICG) angiography is useful to identify the ingrowth site of idiopathic choroidal neovascularization (CNV), which can predict visual outcomes after surgical removal of idiopathic CNV. Design: Consecutive, observational case series. Participants: Twenty-six patients with idiopathic subfoveal CNV, of whom six underwent submacular surgery. Intervention: Indocyanine green videoangiography with a scanning laser ophthalmoscope. Main Outcome Measures: We studied ICG videoangiographic images of choroidal neovascular membranes from the early phase to the late phase with special attention to abnormal findings, which can indicate the ingrowth site of CNV. Results: Early ICG angiography demonstrated distinct neovascular vessels in 24 of the 26 patients (92%). Hypofluorescent rims continuously or intermittently surrounded neovascular membranes on late ICG angiograms in 21 of the 26 patients (81%). In 22 of the 26 patients (85%), ICG angiography demonstrated hypofluorescent areas within the CNV. These hypofluorescent areas frequently became ring shaped in the middle to late phase of the ICG angiography. In 14 of 16 patients (88%) with CNV larger than half a disc area, the filling of neovascular vessels appeared from the inside of the hypofluorescent areas and branched out toward the surrounding hyperfluorescent membrane in the early phase. In all six patients who underwent surgical removal of CNV, ICG videoangiography showed these hypofluorescent areas from which neovascular vessels emanated. Three of the four surgical patients, in whom hypofluorescent areas or central fluorescent areas surrounded by ring-shaped hypofluorescence were extrafoveal or juxtafoveal, had a best postoperative visual acuity of 20/60 or better. In contrast, both surgical patients with subfoveal hypofluorescent areas had a best postoperative visual acuity of 20/70 or worse. Conclusions: Although further observations are needed, ICG angiography may be a useful adjunct in the identification of the ingrowth site of idiopathic CNV, which can predict visual outcomes after surgery. (C) 2000 by the American Academy of Ophthalmology.