Evaluation of retinal sensitivity in photodynamic therapy using verteporfin: A two-year follow-up
H. Elsner, I. Barbazetto, A. Benecke, U. Schmidt-Erfurth
Purpose: To quantify the effect of multiple photodynamic treatments on central retinal function in a prospective, randomized phase III clinical trial during a two year regimen (TAP Investigation)
Methods: Microperimetry using a scanning laser ophthalmoscope (Rodenstock) was used to topographically document retinal sensitivity in 31 treated with repeated verteporfin therapy and 12 eyes of a placebo group as an ancillary study. Size and localization of absolute and relative scotomas and central fixation were documented at baseline and continuously in 3 month intervals up to 24 months. Data were analyzed in a double-masked fashion by two independent observers.
Results: Absolute scotomas demonstrated a mean size of 2.7 mm2 at baseline in both groups. In the verteporfin group absolute defects increased in size to 6.2 mm2 at month 6 and remained stable at 8.6 mm2 at month 12 and 24. Control eyes showed a continuous progression in absolute scotoma size to 11.2 mm2 at 6, 16.4 mm2 at 12 and 31.5 mm2 at 24 months. Relative defects were measured at 7.4 mm2 (verteporfin group) and 8.5 mm2 (control group) at study entry. While relative defects demonstrated only a limited enlargement to 15.8 mm2 at 12 and 20.8 mm2 at 24 months in the verteporfin group, the mean scotoma size rapidly increased in the control group to a final dimension of 37.7 mm2 (12 months)and 48 mm2 (24 months). Verteporfin treated eyes were also more likely to maintain central fixation.
Conclusion: PDT using verteporfin achieves a significant improvement in long-term preservation of central visual field. At 24 month follow-up absolute scotoma were 4.3 times and relative scotomas were 2.3 times larger in the control group than in the verteporfin-treated group.
University Eye Hospital Lübeck, Germany