The optical coherence tomography-based improvement rate in the 30 % - dose PDT group was less than that in the 50 % - dose PDT group both at 6 months ( 73.8 % vs 92.9 % ; = 0.0125 , P = .006 ) and at 12 months ( 75.4 % vs 94.6 % ; = 0.0125 , P = .004 ) .