RETINAL AND CHOROIDAL VESSEL CLOSURE USING PHTHALOCYANINE PHOTODYNAMIC THERAPY

Chloro-aluminum sulfonated phthalocyanine (CASPc) is a photoactive dye capable of generating photochemical reactions when excited with 675 n m light. We used CASPc to produce photochemical closure of retinal med ullary ray vessels and choroidal vessels in normal rabbits. Irradiatio n prior to CASPc injection produced no photographic, angiographic, or histologic lesions in any eyes. Identical irradiation of medullary ray and choroidal vessels after CASPc injection produced complete vessel closure in all eyes. Histopathologic examination showed marked thrombo sis of medullary ray and choroidal vessels, with minimal damage to con tiguous tissues including the neurosensory retina. We conclude that CA SPc can produce profound closure of normal retinal and choroidal vesse ls with minimal deleterious effect on surrounding tissues. (C) 1994 Wi ley-Liss, Inc.