A split-face study: comparison of picosecond alexandrite laser and Q-switched Nd:YAG laser in the treatment of melasma in Asians.

To evaluate efficacy and safety of picosecond 755 nm alexandrite laser as compared to 1064 nm QS-Nd:YAG laser for melasma treatment in Asians. Twelve patients received 4 sessions of treatments at 1-month interval in a split-face manner. The right side of each patient's face received 755 nm picosecond laser, and the other side received 1064 nm QS-Nd:YAG laser. Zoom handpiece of 755 nm picosecond laser at fluence of 0.88-1.18 J/cm2 was applied. The treatment protocol used for 1064 nm QS-Nd:YAG laser was 8 mm spot size at fluence of 2.0 J/cm2 initially followed by 6 mm spot size at fluence of 3.5 J/cm2, and finishing with 4 mm spot size at 3.2 J/cm2. For both 755 nm picosecond laser and 1064 nm QS-Nd:YAG laser, the endpoint was mild erythema and swelling without petechiae. Objective evaluation with visual analogue score was conducted by two independent physicians. Subject self-assessment for each patient was conducted as well. Statistical results showed that higher pigmentation clearance rate was achieved at the 755 nm picosecond laser side after the second treatment. At the 3 months follow-up, greater clearance was observed at the 755 nm picosecond laser side compared to the 1064 nm QS-Nd:YAG side. 755 nm alexandrite picosecond laser has been observed to achieve a faster and better clearance rate for melasma compared to 1064 nm QS-Nd:YAG laser. We conclude that the 755 nm picosecond laser could be a safe and effective modality for melasma treatment in Asians.