Efficacy of verteporfin photodynamic therapy on laser-induced choroidal neovascularization and the ancillary effect on diabetic microvasculopathy.

PURPOSE: To demonstrate the efficacy of photodynamic therapy (PDT) in treating choroidal neovascularization (CNV) induced by laser photocoagulation for diabetic macular edema and its ancillary effect on surrounding diabetic microvascular abnormalities. METHODS: A retrospective interventional case series study in a clinical practice setting of four patients with proliferative diabetic retinopathy and clinically significant macular edema who had developed classic CNV in proximity to the area of previous laser photocoagulation. The lesions were treated with verteporfin PDT and followed with serial fluorescein angiography. RESULTS: Compared to the pre-treatment angiogram, an acute reduction in leakage from CNV was noted as soon as 5 days post-PDT and persisted in some areas up to three months post-treatment within the zone of the typical dark choroid pattern. No evidence of any closure of microaneurysms was noted. CONCLUSIONS: Serial fluorescein angiograms demonstrate that PDT appears to have a beneficial effect on CNV induced by laser photocoagulation for diabetic macular edema without any tangible beneficial effect on diabetic microvasculopathy. PDT had no effect on existing microaneurysms.