Experimental inhibition of corneal neovascularization by photodynamic therapy with verteporfin

Purpose: To investigate the anti-angiogenic effects of photodynamic therapy with verteporfin in a rabbit model of corneal neovascularization. Methods: One week after suturing, the localization of verteporfin in the neovascularized cornea was examined through fluorescent microscopy 1 hr after administration. Rabbits were treated with one or two times of photodynamic therapy with verteporfin at 1-week intervals. Analysis of corneal neovascularization was performed by biomicroscopic and histological examinations. Results: Fluorescent microscopy showed green fluorescence in the vascular walls and interstitial tissue of the corneal stroma. The mean percentages of neovascularized corneal area at 3 days, 1 week, and 2 weeks after one time of photodynamic therapy were 90.3% 3.5%, 71.6% 6.2%, and 43.6% 15.1% in treated eyes and 96.4% 1.9% (p = 0.10), 88.6% 4.6% (p = 0.01), and 76.8% 4.4% (p<0.01) in control eyes, respectively. The mean percentages 3 days, 1 week, and 2 weeks after two times of photodynamic therapy were also significantly lower in treated eyes compared with control eyes. In quantitative histological examination at 1 and 2 weeks after therapy, treated eyes showed significantly less neovascular area and number of vessels than control eyes. Conclusions: Photodynamic therapy with verteporfin is a safe and useful procedure to reduce experimental corneal neovascularization and can be used to inhibit angiogenesis in the cornea.