Photothrombosis of corneal neovascularization by intravenous rose bengal and argon laser irradiation

Management of corneal neovascularization by photocoagulation has been limited and rarely successful. We evaluated the efficacy and safety of the novel technique of photothrombosis to occlude corneal neovascularization. Sixteen rabbit corneas with previous ocular surface wounds that had healed with 360° extensive neovascularization (persistent for 20 months) were used. After an intravenous injection of rose bengal solution (40 mg/ kg of body weight [BW]), each vessel on the upper half of the cornea was occluded with a photochemically induced thrombus within ten shots of argon laser irradiation (514.5 nm, 130 mW, 63 μm, 0.2 s); those on the lower half were used as an internal control. Throughout the four-month study period, the treated vessels remained occluded, as evidenced by corneal fluorescein angiography. Corneal clarity was improved after treatment. A single injection of rose bengal at a dose of 8 mg/kg of BW or higher was sufficient for successful photothrombotic occlusion of corneal vessels within one hour of experimentation. Transient elevations of serum urea nitrogen, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and total bilirubin levels and decrease of serum phosphorus level were noted on the first day after injection with 40 mg/kg of BW of rose bengal solution.