Photodynamic therapy for corneal neovascularization.

Background And Objective: Photodynamic therapy with tin ethyl etiopurpurin (SnET2) was evaluated as a treatment modality for rat corneal neovascularization.

Materials And Methods: Escalating light doses at 664 nm were applied focally to corneal neovascularization in rats 10 minutes following an intravenous injection of SnET2 using a low-power diode laser. Controls consisted of light-only and drug-only treatments. Clinical, angiographic, and histopathologic evaluations were performed on the animals up to 28 days after drug and/or light treatment.

Results: A drug and light dose-response was seen in producing neovessel closure. In animals treated with SnET2 and the highest light dose (25 J/cm2), all eyes showed occlusion at every follow-up evaluation up to 28 days. Control eyes demonstrated progressive disease at all time points.

Conclusions: Photodynamic therapy appears to be safe and effective for eliciting prolonged (> 28 days) occlusion of corneal neovascularization in the rat model with minimal side effects and good clinical outcomes.