Indocyanine green angiography and histopathology of choroidal neovascular membrane in age-related macular degeneration

Purpose: Histopathological investigation of the choroidal neovascular membrane (CNM) in age-related macular degeneration (AMD) patients who showed various findings in indocyanine green angiography (IA). Methods: Before surgery, 20 eyes of 20 patients were classified into four types based on IA findings (Type I: both early and late phase hyperfluorescence; Type II: hyperfluorescence only in the early phase; Type UI: hyperfluorescence only in the late phase, Type IV: virtually no hyperfluorescence in any phase). Seventeen surgically excised specimens stained with hematoxylin-eosin and azan, were examined by light microscopy. Three other specimens were examined by electron microscopy. Results: Type I membrane showed many vascular channels not present in the surrounding retinal pigment epithelium (RPE) cells, and little fibrous tissue. Type II membrane had many vascular channels but RPE cells surrounded the CNM. Type III membrane showed few vascular channels and RPE cell proliferation. Type IV membrane showed dense fibrous tissue. Conclusion: The IA findings in AMD agreed with the CNM membrane structure in regard to the number of vascular channels, maturity of vessels, the extent of envelopment of RPE cells and the amount of fibrous tissue. (C) 2000 Japanese Ophthalmological Society.