Indocyanine green angiography and transmission defects

Purpose: Several reports have suggested that indocyanine green angiography is of value in identifying late hyperfluorescent subretinal tissue presumed to be choroidal neovascularization. However, fluorescein angiography may also reveal late hyperfluorescence from transmission defects caused by atrophy of the retinal pigment epithelium. We studied the indocyanine green angiographic characteristics of transmission defects to determine if indocyanine green angiography can differentiate choroidal neovascularization from the retinal pigment epithelium atrophy. Methods: Indocyanine green angiograms of 23 eyes with geographic atrophy secondary to age-related macular degeneration and without any signs or history of choroidal neovascularization were reviewed. Results: Indocyanine green angiography demonstrated late hypofluorescence of various degrees in the area of geographic atrophy. There was no evidence of late hyperfluorescence. Conclusion: Late hyperfluorescence evident on fluorescein angiography which can be caused by choroidal neovascularization or transmission defects is not seen in retinal pigment epithelium atrophy imaged by indocyanine green angiography. According to these results indocyanine green angiography is useful to differentiate occult choroidal neovascularization from areas of retinal pigment epithelium atrophy.