Abstract: 【Abstract】 Objective To explore and establish a method for quantitative evaluation of facial skin pores based on dermoscopy, and to evaluate the scientificity and practicability of this method. Methods Totally, 30 patients with enlarged facial skin pores were enrolled from Department of Dermatology, Peking University Third Hospital between June 2017 and December 2017, and treated with 2 940 nm Er pixel laser. Photographs were taken, and dermoscopic images were collected before and after treatment. According to the standard photographs of facial pores, the improvement of enlarged facial pores was evaluated by comparing the photos before and after the treatment. A dermoscope-based pore detection system was established, and quantified indices for pore area and color difference before and after the treatment were evaluated by using this system. A pre-post self-contrast study was conducted, and statistical analysis was carried out by using paired t test for the comparison of measurement data and paired non-parametric test （Wilcoxon signed-rank test） for the comparison of ranked data. Results After the treatment, the standard photograph method for the assessment of facial pores showed score reduction by 3 grades in 1 of the 30 patients （3.3%）, by 2 grades in 7（23.3%）, by 1 grade in 21（70%）, and no changes of grades in 1（3.3%）. Additionally, the differences between pre- and post-treatment grades were significant （Z = -4.94, P < 0.01）. The detection rate of skin pores by using the detection system was （70.59 ± 3）%. After the treatment, the quantified values of pore area and color difference both significantly decreased compared with those before the treatment （pore area: 712.95 ± 87.45 vs. 831.45 ± 88.92, t = 5.70, P < 0.05; color difference: 23.82 ± 9.43 vs. 28.92 ± 9.91, t = 2.76, P < 0.05）. Conclusion The dermoscopy-based method for quantitative evaluation of skin pores after the treatment with 2 940 nm Er pixel laser showed highly consistent results with the standard photograph method, which can be further verified and popularized in the evaluation of enlarged skin pores.

Key words: Dermoscopy, Image processing, computer?assisted, Laser therapy, Skin pore widening