Objective: To compare the effectiveness of photodynamic therapy to close experimental choroidal neovascularization using an intravenous infusion of liposomal benzoporphyrin derivative (verteporfin) with previous work using a rapid intravenous injection, before initiating clinical trials.
Methods: Choroidal neovascularization was induced in cynomolgus monkey eyes using argon laser. Liposomal benzoporphyrin derivative was delivered by an intravenous infusion pump for 10 or 32 minutes at a dose of 0.375 mg/kg. Irradiation was performed with 689- or 692-nm laser light (600-mW/cm2 irradiance and 150-J/cm2 fluence) in 7 normal eyes and 11 eyes with choroidal neovascularization between 30 and 105 minutes after the start of dye infusion. Findings were documented by fundus photography, fluorescein angiography, and light and electron microscopy.
Results: Irradiation within 32 to 50 minutes of the start of the fast (10 minutes) or slow (32 minutes) dye infusion resulted in closure of choroidal neovascularization. In normal eyes, this technique caused choriocapillaris closure and retinal pigment epithelium damage with minimal damage to surrounding tissues.
Conclusion: Photodynamic therapy using intravenous infusion of liposomal benzoporphyrin derivative selectively closed experimental choroidal neovascularization. This may be a suitable modality for clinical use.