Timing of Intervention: A Comparison of Photodynamic Therapy on Choridal Neovascularization at 6 Weeks and 3 Months

Abstract

Abstract: : Purpose: To explore whether there is a difference in the size of active choridal neovascularization (CNV) lesions in patients with age-related macular degeneration (AMD) at 6 weeks and 3 months post initial photodynamic therapy treatment with Verteporfin (Visudyne). Methods: A total of 44 patients with AMD and predominately classic CNV were enrolled in the study. Due to a change in methodology at our institution we were able to retrospectively measure CNV lesions in two distinct subgroups of 22 patients that were treated at 6 weeks and 3 months respectively with intravenous fluorescence angiograms (IVFA) post photodynamic therapy with Verteporfin (Visudyne). The dimensions measured included greatest linear diameter (GLD) and total area of the CNV lesion with exclusion of blood. Results: Patients that were followed at 6 weeks showed an average decrease in CNV size of 0.442 mm in GLD and 1.227 mm2 in area. Those patients followed at 3 months showed an average increase in CNV size of 0.405 mm in GLD and 0.887 mm2 in area. Both the average change in GLD and area showed a statistical significance difference (P=0.0123 and 0.0121 respectively). Conclusions: These results suggest that the beneficial effect of photodynamic therapy in decreasing the size of the CNV lesions is greater within first 6 weeks and appears to decrease with time. Evaluation of both groups following the second PDT treatment is currently ongoing.

Keywords: age-related macular degeneration • photodynamic therapy • choroid: neovascularization