Abstract
Abstract: :
Purpose: To determine the efficacy of photodynamic therapy (PDT) with verteporfin (Visudyne®, Novartis AG) as a treatment option for corneal neovascularization in a rabbit model. Methods: Corneal neovascularization was induced in Dutch-belted rabbits by placing an intrastromal silk suture near the limbus. Verteporfin was administered by i.v. injection (1.5mg/kg) followed by the application of laser light using three different energy levels (17, 50, and 150 J/cm2). Verteporfin pharmacokinetics and PDT-induced regression of the induced neovascularization were analyzed. Histology was used to examine the interaction of PDT with anterior segment ocular tissues. Results: Corneal regions with neovascularization showed significant time-dependent accumulation of verteporfin following i.v. injection. The application of laser light after verteporfin injection resulted in an initial mean regression of 50% to 70% in the area containing neovascularization in all groups, 2 days post-laser treatment. Rabbits treated with laser energy levels of 17 and 50 J/cm2 showed rapid regrowth of the new blood vessels. However, in the group that received 150 J/cm2, vessel regression was maintained throughout the 9-day post-laser study period. Histologic examination of the anterior segment following PDT (150 J/cm2) showed localized degeneration of the new blood vessels without observable change in other anterior segment structures. Conclusions: The results of this study provide evidence that PDT with verteporfin is efficacious for the treatment of corneal neovascularization in the eyes of Dutch-belted rabbits.
Keywords: 483 neovascularization • 516 photodynamic therapy • 316 animal model