Pump-probe imaging was first used for quantitative analysis of melanin in dark circles’ skin to improve the ability to diagnose and treat dark circles on human skin. This study aimed to compare the distribution characteristics in melanin of lower eyelid skin tissues and to determine whether pump-probe imaging has potential for the classification of dark circles in vivo. Specimens obtained from 15 patients undergoing blepharoplasty were examined using pump-probe imaging. Furthermore, adjacent slices were respectively treated with hematoxylin–eosin (HE) and ferrous sulfate (FeSO4) staining for cross-references. Subsequently, the melanin content index (MCI) and mean fluorescence intensity (MFI) were quantitatively analyzed by the pump-probe imaging. The distribution of melanin granules in the pump-probe image and FeSO4 staining was consistent. Meanwhile, the tissues of the skin with dark circles and normal skin demonstrated significant differences in MCI and MFI. These differences can be used to distinguish the skin with dark circles from the normal skin. Pump-probe imaging could be used for the analysis of the microstructure and spectral characteristics of melanin granules in skin with dark circles. Significant differences were noted between the pigmented type of dark circles and the other two groups (normal skin and the vascular type of dark circles), while no significant differences were found between normal skin and the vascular type of dark circles.

Objective: In recent years, the microneedle radiofrequency (MRF) has been widely used for skin rejuvenation, but histological studies on the immediate trauma caused by different parameters of non-insulated RF microneedles Methods: The skin of three pigs was treated with different needle depths, pulse widths and energy levels of non-insulated microneedle RF. Samples were collected before, immediately, and 2 weeks after treatment. The immediate histological response of each group was assessed and quantified by hematoxylin and eosin staining, Masson staining and Victoria Blue staining. Results: In the treatment of non-insulated microneedle RF, different energy levels affected mainly the range of thermal damage (p = 0.044), and different needle depths affected mainly the depth of the cavity (p = 0.022). But the width of the coagulation zone width was determined by different factors. There was no significant difference in the histology of immediate damage caused by different pulse widths.Reepithelialization of the epidermis and basic wound repair can be completed within 2 weeks. Conclusion:Non-insulated RF microneedle therapy is an effective and safe treatment that can stimulate dermal wound healing with less thermal coagulation and a wide range of reversible thermal damage. However, it should be noted that the set needle depth may not correspond to the actual penetration depth, nor to the actual depth of histologic trauma.

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Objective To evaluate the efficacy and safety of fractional 1064 nm picosecond Nd:YAG laser (FPNYL) in the treatment of post‐acne erythema (PAE) of adult Chinese. Materials and methods A total of 22 patients received 1 session of treatment and were followed up at the eighth week. Primary outcomes were measured by the Clinician erythema assessment scale (CEAS). Secondary outcomes included a global aesthetic improvement scale (GAIS) and patients’ assessment of satisfaction on a five‐point scale. Pain scores and adverse effects were also evaluated. Results Twenty‐two patients with Fitzpatrick skin types III and IV were enrolled in the study and completed all treatments and follow‐up visits. The mean CEAS scores fell from 2.74 ± 0.80 to 1.95 ± 0.75 (p < 0.05). The mean GAIS of PAE improvement was 2.46 ± 0.68. Erythema percentile scores by VISIA increased from 32.63 ± 7.0 to 45.75 ± 11.45 (t = 5.442, p = 0). The patient satisfaction score was 1.86 ± 1.17. The pain scores were 3.27 ± 1.17 for the FPNYL treatment (varied from 2 to 6). There were moderate erythema and oedema, which last for 3.84 ± 0.78 days. There were overall 68.18% (15/22) patients who felt pruritus in different degrees and 27.27% patients who encountered acne eruptions (white head type). No scar, hyperpigmentation or hypopigmentation was found. Conclusion Treatment with fractional 1064 nm picosecond Nd:YAG laser is effective and safe for PAE of Chinese patients.