Photodynamic therapy of subretinal neovascularization in the monkey eye

Experimental subretinal neovascularization in the monkey eye was treated by photodynamic therapy with rose bengal. Following intravenous injection of rose bengal, the subretinal vessels were irradiated with filtered light. Successful treatment was achieved, provided the subretinal vessels were irradiated during the period in which the dye was present in and around the subretinal vessels but had already cleared from the retinal vasculature. The successfully treated lesions demonstrated replacement of the leaking and pooling subretinal vessels with a non-leaky scar. Morphologic evaluation revealed immediate destruction of the subretinal plexus, with minimal damage to the overlying retina. The destroyed subretinal tuft was replaced by a scar containing mainly fibroblasts embedded in collagen fibers. Our results suggest that photodynamic therapy is potentially useful for destruction of subretinal vessels without damaging the overlying retina.