Purpose: To compare the short-term efficacy and safety of standard verteporfin photodynamic therapy (PDT) to modified PDT regimen using a twofold illumination scheme for treating choroidal neovascularization in pathologic myopia.
Methods: Randomized active-controlled clinical trial including 16 patients with subfoveal choroidal neovascularization caused by pathologic myopia and best-corrected visual acuity (BCVA) of 20/320 or better. Patients were randomly assigned (1:1) to standard PDT regimen (50 J/cm; n=8) or twofold illumination PDT scheme (50+50 J/cm; n=8). Comprehensive ophthalmic evaluation including fluorescein angiography was performed at baseline and at weeks 1, 12+/-2, and 24+/-2 following treatment. At week 12 follow-up examination, an additional treatment session with either standard or modified PDT regimens (as assigned at baseline) was applied to areas of fluorescein leakage if present. Changes in BCVA, retreatment rate, and incidence of adverse events were evaluated.
Results: All patients completed the 24-week study period. Baseline median BCVA was 20/100 and 20/100 for patients assigned to standard and modified PDT regimens, respectively. At week 24, median improvement in BCVA was significantly greater in patients submitted to twofold illumination PDT scheme (P=0.005; Mann-Whitney U test). Median change from baseline in BCVA (ETDRS lines) was +1.8 (P<0.05; Wilcoxon signed-rank test), +0.4, and +0.5 lines for patients submitted to standard PDT regimen, and +1.8 (P<0.05; Wilcoxon signed-rank test), +1.9 (P<0.05; Wilcoxon signed-rank test), and +2.4 (P<0.05; Wilcoxon signed-rank test) lines for patients submitted to twofold illumination PDT scheme at week 1, 12, and 24 follow-up examinations, respectively. An additional PDT session was performed in 7/8 patients assigned to standard PDT regimen, and in 4/8 patients assigned to modified PDT (P=0.28; Fisher exact test). No PDT-related complications were observed.
Conclusion: Although the number of patients and length of follow-up in this study was limited, a better visual outcome and diminished retreatment rate were observed in patients assigned to twofold illumination PDT scheme in comparison to those submitted to standard PDT regimen. Larger studies with longer follow-up to look at twofold illumination PDT scheme versus standard one to confirm our preliminary results are warranted.