Comparison between 16-week follow-up and baseline photography scores ( from -2 to +2 on a Likert scale , with > 0 being improvement ) were a mean score for PDL of 1.7 ( 95 % CI 1.4 , 2.0 ) and for IPL 1.4 ( 0.9 , 1.8 ) , with a mean difference between PDL and IPL of -0.3 ( -0.5 , -0.1 ) ( P = 0.01 ) .