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Indocyanine green angiography patterns of zones of relative decreased choroidal blood flow in patients with exudative age-related macular degeneration.

BACKGROUND AND OBJECTIVE
To investigate the incidence and patterns of posterior zones of relative decreased choroidal blood flow in patients with exudative age-related macular degeneration.


PATIENTS AND METHODS
Digital indocyanine green (ICG) angiograms from 100 patients with exudative age-related macular degeneration were reviewed for the presence of posterior zones of relative decreased choroidal blood flow. The patterns of these zones and their location relative to the choroidal neovascular process were noted.


RESULTS
Ninety-five percent of the angiograms displayed the presence of either a complete or an incomplete zone of relative choroidal hypoperfusion. The zone was most apparent in the early frames of the angiogram. Five different patterns of relative decreased choroidal blood flow were identified: horizontal (32%), vertical (14%), bipartite (9%), tripartite (31%), and quadripartite (9%). The choroidal neovascular process was located within or at the edge of the zone of relative choroidal hypoperfusion in all cases.


CONCLUSION
Most cases of choroidal neovascularization localize to areas of relative choroidal dye nonfilling on ICG angiography. These patterns of choroidal nonfilling may have implications in the pathogenesis and management of choroidal neovascular membranes in age-related macular degeneration.