PHTHALOCYANINE PHOTODYNAMIC THERAPY - NEW STRATEGY FOR CLOSURE OF CHOROIDAL NEOVASCULARIZATION

Chloro-aluminum sulfonated phthalocyanine (CASPc) is a photochemically active dye employed in photodynamic therapy (PDT). CASPc is a potent generator of singlet oxygen when irradiated with 675 nm light and is a lso capable of fluorescence, allowing visualization of the dye in tiss ues. We devised an angiography system using CASPc fluorescence to dete rmine its localization in experimental choroidal neovascularization in monkeys and then investigated the ability of CASPc to produce photoch emical closure of neovascularization upon irradiation with 675nm laser light. Fluorescent imaging indicated that CASPc localized angiographi cally in areas of neovascularization for at least 24 hours. Irradiatio n with 675 nm laser light 5-30 minutes after CASPc injection produced complete closure of choroidal neovascularization with minimal damage t o overlying retina. We conclude that CASPc localizes in neovascular ch oroidal vessels and that CASPc photodynamic therapy can produce closur e of these choroidal vessels. (C) 1994 Wiley-Liss, Inc.