Polypoidal choroidal vasculopathy: angiographic characterization of the network vascular elements and a new treatment paradigm.
Macular exudative manifestations secondary to choroidal neovascular lesions remain the leading cause of definitive visual impairment and legal blindness in the elderly. During the past decade, advances in ophthalmic imaging systems have enabled the recognition of presumed new distinct choroidal neovascular lesions that share some unique clinical and angiographic peculiarities as well as better comprehension of the pathophysiologic mechanisms related to such entities. Amongst presumed newer exudative maculopathies, polypoidal choroidal vasculopathy, which has been described as a distinct choroidal abnormality characterized by inner choroidal vascular network of vessels ending in polyp-like structures only identified on indocyanine green angiography and mostly affecting African-American and Asian descendents, has gained special interest from the ophthalmic community particularly because of its growing recognition among patients with clinical appearance of neovascular age-related macular degeneration. Thus far, however, the exact nature of the vascular structure of the polypoidal choroidal vasculopathy lesion remains unclear and data from recent studies have conflicted with the initial concept of a benign exudative maculopathy with long-term preservation of good vision. All together, such factors make difficult the establishment of an appropriate treatment, if any, for the entity. Herein, by using a modified technique of conventional indocyanine green angiography, we demonstrate new information about the morphologic characteristics, and to some extent the blood flow dynamics perfusion, of the polypoidal choroidal vasculopathy lesion. Our results suggest that the PCV lesion should be considered a variety of choroidal neovascularization rather than a distinct clinical entity, characterized by one single large neovascular complex presenting well-defined arterial neovascular vessels arising from one major "ingrowth site" and draining vessels that present aneurysm-like dilations corresponding to the polyp-like structures typically described for the entity. Finally, the visual acuity and angiographic findings observed after selective ingrowth site photothrombosis corroborate the existence of one major "ingrowth site" for the PCV neovascular complex and point toward a new treatment paradigm for this variety of choroidal neovascularization.