[Comparison between indocyanine green angiography and histopathological observations of choroidal neovascular membrane in age-related macular degeneration].

We classified choroidal neovascular membrane (CNM) (20 eyes) in age-related macular degeneration into four types (Type I: hyperfluorescence in both early and late phases, Type II: hyperfluorescence only in the early phase, Type III: hyperfluorescence only in the late phase, Type IV: virtually no hyperfluorescence in any phase) using indocyanine green angiography (IA). We performed surgery to remove CNM with these IA findings. After 17 surgically extracted specimens had been stained with hematoxylin-eosin and azan, they were examined by tight microscopy. Three other specimens were examined by electron microscopy. Type I showed many vascular channels, not present in the surrounding retinal pigment epithelium (RPE) cells, and little fibrous tissue. Type II had many vascular channels but RPE cells surrounded the CNM. Type III showed few vascular channels and RPE cell proliferation. Type IV showed abundant fibrous tissue. The IA findings of CNM were thought to be determined by the number of vascular channels, maturity of vessels, degree of surrounding by RPE cells, and the amount of fibrous tissue within the CNM.