Argon Laser Photodynamic Therapy of Human Corneal Neovascularization After Intravenous Administration of Dihematoporphyrin Ether

Long-term evaluation of dihematoporphyrin ether (DHE) safety and efficacy as photodynamic therapy (PDT) for patients with corneal neovascularization (KNV). Prospective multi-center interventional case series. Seven patients were enrolled after Institutional Review Board approval and a detailed informed consent were obtained. Eligible patients presented with clinically stable KNV without active vessel progression or inflammation. All patients with severe hypertension, history of renal or hepatic disease, or sensitivity to porphyrins, and those with active keratitis or uncontrolled ocular surface disease were excluded. DHE was administered as an intravenous bolus (2 mg/kg). Seventy-two hours later, PDT was carried out using argon green laser (514 nm). The main outcome measure, extent of vascular thrombosis, was estimated during postoperative follow-up examinations performed at day 1, 1 week, 6 months, and up to 12 years postoperative. All patients obtained an immediate reduction in measurable corneal vascularization. With at least 6 months of follow-up, six of seven patients maintained a significant reduction (52.5% ± 19.6%, P < .01) in KNV. The mean length of followup was 5.4 years (Range = 6 months to 12 years) during which time there were no other ocular changes attributable to laser treatment. Three patients suffered significant systemic short-term phototoxicity reactions. Intravenous DHE followed by photodynamic treatment in humans is effective for the reduction of inactive, established KNV. However, the significant short-term adverse effects related to systemic administration of this drug are of particular concern and warrant further investigation.