Abstract
Abstract: :
Purpose: Photodynamic therapy (PDT) using standard treatment parameters is associated with characteristic collateral changes in the physiological choroid. A modification of treatment parameters was used to increase the selectivity of the approach. Methods: 20 patients with predominantly classic choroidal neovascularization (CNV) were treated in a dose finding study, a comparison group of 41 patients was treated with standard PDT. Modified treatment parameters included a bolus administration of verteporfin at 6 mg/m² in all cases followed by laser irradiation after 5 (group A) or 15 ( group B) minutes. Groups A and B were both treated with 50J/600mW. 15 min. after bolus, two additional groups were treated with 25J/cm²: Group C using 300 mW over 83s and group D using 600 mW over 41s. Evaluation criteria were best corrected ETDRS visual acuity, CNV size and leakage in fluorescein angiography and choriocapillary nonperfusion in ICGA. All 61 patients were seen at baseline, 1 day, 1 week, 4 weeks and at 3 months. Results: Most patients in the standard treatment group as well as in the bolus groups with high light dose (A and B) had lost 1 line at 3 months. A mean gain of 1 line gain was, however, seen in groups C and D treated with a lower light dose of 25J. CNV closure was observed in all groups with an identical pattern of minimal size at 1 day and slow regrowth during the following weeks. Leakage typically increased at one day for all groups, except for the 25J/300mW group C. PDT effects on the surrounding choroid with regard to choriocapillary nonperfusion was most intensive in the 50J/5min/600mW group A. Only minimal or no choroidal hypofluorescence was seen in groups C and D treated with a reduced light dose at 15 min. Conclusions: In comparison to the standard PDT regimen, a bolus administration together with a reduced light dose obtained the most favourable results with improvement in vision, efficient early closure of the CNV and a significantly reduced collateral effect in the choroid. A selective sparing of the choroid may be an advantage in PDT monotherapy as well as combination therapy using antiangiogenic drugs as adjunct.
Keywords: photodynamic therapy • age–related macular degeneration • choroid: neovascularization