Theoretical invetigation of the role of choriocapillari blood flow in treatment of ubfoveal choroidal neovacularization aociated with age-related macular degeneration

PURPOE: To invetigate the relationhip between choriocapillari blood flow and blood flow through an overlying choroidal neovacularization, a it relate to photocoagulation-induced change in the choriocapillari circulation. METHOD: A theoretical model that imulate the blood flow in the choriocapillari and choroidal neovacularization of the human eye wa developed, baed on hitologically determined vacular geometry and experimentally meaured blood preure gradient. The choriocapillari blood preure and blood flow were examined before and after imulated photocoagulation of variou attler layer veel entering the choriocapillari in the vicinity of the choroidal neovacularization. (The attler layer i the inner layer of medium-ized choroidal veel that include both arteriole and venule that upply the choriocapillari.) REULT: The theoretical model howed that both partial and complete occluion of either attler arteriole or venou veel in the vicinity of the capillary-like veel connecting a choroidal neovacularization to the underlying choriocapillari reult in ignificant choroidal neovacularization blood flow reduction. Thee theoretical reult are imilar to clinically oberved change induced by laer photocoagulation of feeder veel. (In thi dicuion, the term “feeder veel” refer to thoe veel in an indocyanine green angiogram image that appear to upply blood to a choroidal neovacularization; thee veel appear to be attler layer veel, rather than the hitologically demontrated hort, capillary-like veel that form choriocapillari-choroidal neovacularization communication.) CONCLUION: Reduction of choriocapillari blood flow underlying a choroidal neovacularization may be ufficient to reduce the blood flow rate in the choroidal neovacularization and thereby reduce the aociated retinal edema. The reult alo ugget that reduction of choriocapillari blood flow may be the common hemodynamic event aociated with the ucceful application of everal currently practiced method of choroidal neovacularization treatment, including feeder veel photocoagulation, photodynamic therapy, tranpupillary thermotherapy, and prophylactic druen photocoagulation. Ultimately, thi model may be ueful in determining optimal placement of laer photocoagulation burn to achieve a deirable perturbation in choroidal blood flow ditribution and thereby reduce choroidal neovacularization blood flow to the extent neceary to obliterate aociated retinal edema.