Abstract
Abstract: :
Purpose: To evaluate the effect of high dose photodynamic therapy directed to feeder vessels in eyes with age related macular degeneration complicated by choroidal neovascularization of the minimally classic type . Methods: FDA approval was obtained to perform a dose escalating study of Visudyne therapy for patients with CNV who had a single identifiable feeder vessel seen by high speed ICG SLO angiography (Heidelberg Retinal Angiograph). Feeder vessels were treated with a single treatment of a therapy placed in a 800–1200 micron spot after infusion of Visudyne. All feeder vessels were extra–foveal, and the fovea was not irradiated. A dose escalating study was performed with light doses ranging between 50 and 125 Joules per square centimeter (between 1x and 2.5 x the usual dose for Visudyne therapy. Patients were followed without any other treatment for three months. The main outcome measure was change in ETDRS vision; secondary outcome measures included angiographic leakage and lesion size. Results: A total of 7 eyes were treated. Mean Vision change at three months from baseline was 2.2 lines of improved vision P=0.06. Angiography revealed lower perfusion or absence of perfusion of the feeder vessel after treatment and in most cases, less leakage was seen. Conclusions: Feeder vessels can now be identified using high speed SLO angiography in some eyes with sub–foveal choroidal neovascularization. Closure of these feeder vessels is difficult with conventional thermal lasers, but vessel closure is more easily attained with verteporfin. There is no evidence of retinal damage outside of the treatment spot even with high doses of light therapy. Photodynamic ablation of feeder vessels can be performed with a single treatment and may be worthy of further clinical trials. Support; QLT inc, Vancouver Canada and Retina Research Fund (WRF)
Keywords: age-related macular degeneration • choroid: neovascularization