Efficacy and safety of a novel 785 nm picosecond neodymium-doped yttrium aluminum garnet laser for the treatment of facial benign pigmented lesions in Asian skin: a pilot study

BACKGROUND AND OBJECTIVES

Benign pigmented lesions and a general uneven tone in people with skin of color are growing issues that have been presented to dermatologists. To the best of our knowledge, this is the first controlled study to examine the efficacy and safety of using the newly introduced 785 nm neodymium-doped yttrium aluminum garnet (Nd:YAG) picosecond laser to treat facial benign pigmented lesions in Asian patients with diffractive lens array.

MATERIALS AND METHODS

A 785 nm Nd:YAG picosecond laser was used to treat 15 healthy female volunteers older than 18 years who had Fitzpatrick skin types II-IV and facial benign pigmented lesions. Each volunteer received five weekly treatments in dual modes. The clinical improvement was assessed by independent investigators and by objectively measuring the melanin index.

RESULTS

After the treatment, the melanin and erythema indices decreased, and the pigmented lesions showed clinical improvements. No serious adverse effects were observed during the study period.

CONCLUSIONS

A 785 nm Nd:YAG picosecond laser may be safe and effective in treating facial benign pigmented lesions in Asian skin.

Efficacy and Safety of Low-Fluence 730-nm Picosecond Laser in the Treatment of Melasma in Chinese Patients

BACKGROUND

The 730-nm picosecond laser has shown promise in treating various benign pigmentary conditions, and it is yet to be determined whether it is effective and safe for melasma.

OBJECTIVE

The aim of this study was to investigate the potential benefits and risks of using the 730-nm picosecond laser to remove melasma.

MATERIALS AND METHODS

This is a retrospective review of all patients who presented to the clinic between April 2021 and April 2022 for the treatment of melasma with 730-nm picosecond laser alone. The efficacy of the laser was assessed based on the Melasma Area and Severity Index (MASI) score using high-resolution photographs evaluated by blinded dermatologists.

RESULTS

A total of 25 Chinese with Fitzpatrick skin Type II to IV were included. Patients were treated for an average of 3.56 ± 0.77 treatment sessions. The mean MASI scores decreased by 33.7% from 11.38 ± 6.60 to 7.55 ± 6.08 at an average of 8.48 ± 2.16 weeks of follow-up (p < .001). Among the patients, 1 experienced a 79% decrease, 6 had a decrease ranging from 51% to 75%, 10 had a decrease ranging from 26% to 50%, 5 had a decrease of less than 25%, and 3 experienced no changes in MASI scores. No hyper/hypopigmentation was observed.

CONCLUSION

Low-fluence 730-nm picosecond laser is an effective and safe modality for the treatment of melasma in Chinese patients.

Comparison of the efficacy and safety of a 730-nm picosecond titanium sapphire laser and a 1064-nm picosecond neodymium yttrium aluminum garnet laser for the treatment of acquired bilateral nevus of Ota-like macules: A split-face, evaluator-blinded, randomized, and controlled pilot trial

BACKGROUND

The picosecond neodymium yttrium aluminum garnet laser (PNYL) has been successfully used in treating acquired bilateral nevus of Ota-like macules (ABNOM). The 730-nm picosecond titanium sapphire laser (PTSL) is an emerging tool for pigmentary disorders. However, no studies have compared two different wavelengths of picosecond laser for the treatment of ABNOM.

AIMS

To compare the efficacy and safety of the 730-nm PTSL with the 1064-nm PNYL in the treatment of ABNOM.

METHODS

Fifteen participants with ABNOM were randomized to undergo a single session of either the 730-nm PTSL on one side of the face and 1064-nm PNYL on the other side. Efficacy and safety assessments were performed by blinded visual evaluations at baseline, 12 weeks, and 24 weeks posttreatment. Participants' satisfaction and adverse effects were recorded.

RESULTS

Compared to baseline, The 730-nm PTSL-treated side showed better improvement than that of the 1064-nm PNYL-treated side at 24 weeks posttreatment (1.67 ± 1.047 vs. 0.87 ± 0.640, p = 0.027). There were no significant differences in pain sensation and participants' satisfaction between the two laser treatments.

CONCLUSIONS

The 730-nm PTSL is more effective than the 1064-nm PNYL in the treatment of ABNOM.

Picosecond lasers in cosmetic dermatology: where are we now? An overview of types and indications

Q-switched lasers have undeniably revolutionized the field of laser dermatology since four decades ago. Just as the first-generation laser emits its photonic signal in a few nanoseconds, the picosecond laser delivers pulse widths of at least ten times shorter. These devices offer a powerful tool for treating a wide range of skin conditions with a minimal downtime for visible improvement. For the current study, a literature research was performed on the dermatological applications of picosecond laser. The literature searched on this topic between 1999 and 2023 accessible through various platforms produce a result of 62 articles. The included studies have discussed the application of picosecond laser technology in tattoo removal, treatment of epidermal and dermal pigmentation, and collagen remodeling. After sifting the data from the articles into tables, the results were discussed in detail. The study shows a lot of evidence towards the efficacy of picosecond laser, yet it draws attention to its downsides.

Comparison of the efficacy and safety of a 730 nm picosecond titanium sapphire laser and a 755 nm picosecond alexandrite laser for the treatment of freckles in Asian patients: A two-center randomized, split-face, controlled trial

OBJECTIVE

The 730 nm picosecond titanium sapphire laser is a novel laser that shows promising results in treating freckles. This study aimed to further investigate the efficacy and safety of the 730 nm picosecond titanium sapphire laser for treating freckles in Asian patients compared with those of the 755 nm picosecond alexandrite laser.

METHODS

Each face of 86 participants was split into two parts and randomly assigned either one session of 730 or 755 nm picosecond-laser treatment each. Efficacy and safety were determined based on blinded visual evaluations and self-reports at each follow-up visit.

RESULTS

The treatment outcomes of the 730 nm picosecond laser for the treatment of freckles were comparable to those of the 755 nm picosecond laser, with 68.99 ± 7.42% and 69.27 ± 7.75% clearance, respectively (p > 0.05). Participants achieved similar Global Aesthetic Improvement Scale scores (4.04 ± 0.31 vs. 4.02 ± 0.30, respectively [p > 0.05]). Additionally, the 730 nm picosecond laser was perceived to be less painful than the 755 nm picosecond laser (4.69 ± 1.63 vs. 5.65 ± 1.80 nm, p < 0.0001).

CONCLUSION

The 730 nm picosecond laser is safe and effective for the treatment of freckles in Asian patients. Besides, the 730 nm picosecond laser is less painful than the 755 nm picosecond laser.

An update on fractional picosecond laser treatment: histology and clinical applications

Picosecond lasers have a very short pulse duration and a high peak power density. When fractional optical delivery systems are attached to picosecond lasers, they generate an array of concentrated microspots with a high fluence surrounded by areas with a low fluence. This article discusses the histologic characteristics and clinical applications of fractional picosecond laser treatment. Fractional picosecond laser produces laser-induced optical breakdown (LIOB) and laser-induced cavitation (LIC) in the epidermis and dermis respectively, and can encourage skin regeneration and dermal remodeling. It has been shown that fractional picosecond laser has a positive effect on facial photoaging, enlarged facial pores, dyspigmentation, wrinkles, and atrophic scars. Further research is still needed to confirm the benefits of fractional picosecond lasers.

Treatment of facial pigmented disorders with a 785-nm picosecond Ti:sapphire laser in Asians: A report of three cases

Since the advent of the theory of selective photothermolysis, the importance of targeting the chromophore and minimizing the surrounding damage has been extensively discussed. Picosecond-domain laser (ps-laser) treatment with a wide range of wavelengths is an emerging option for various pigmented lesions; however, no definitive treatment choice has been confirmed. The authors aimed to investigate the efficacy and safety of a ps-laser with a 785-nm wavelength for the treatment of facial pigmented lesions in Asians. Three Korean patients with facial pigmented lesions were recruited for the study. A 785-nm ps-laser with a fractionated and an unfractionated handpiece was utilized to administer the treatment. The clinical outcome was evaluated by a clinician by comparing pre- and post-treatment photographs. All patients exhibited a significant improvement in pigmented lesions including freckles, lentigines, and melasma, after three to four sessions of treatment. No adverse events, including post-inflammatory hyperpigmentation or hypopigmentation were observed. In conclusion, this novel 785-nm Ti:sapphire ps-laser may be an effective and safe modality for treating pigmented lesions in skin of color.

Treatment of melasma with a low-fluence 1064 nm Q-switched Nd:YAG laser: Laser toning in Caucasian women

BACKGROUND AND OBJECTIVES

Melasma is a common, therapeutically challenging, and very often relapsing disorder of hyperpigmentation most often observed in women. Low-fluence, multipass technique with Q-switched-mode laser-"laser toning" is broadly used to treat melasma, especially in Asia. The study aimed to evaluate the effects of a series of laser treatments with very short, nanosecond pulses in the treatment of melasma in Caucasian women.

MATERIAL AND METHODS

Forty polish females with Fitzpatrick skin phototype II-III and melasma were treated with 1064 nm Q-switched neodymium:yttrium-aluminum-garnet (QSNY) laser (pulse with 5 ns; spot size, 6-8 mm; fluence, 1.7-3.2 J/cm² ; 2-8 passes; nine treatments). Melanin index (MI), erythema index (EI) by Mexameter MX18®, the modified Melasma Area Severity Index (mMASI), and the participant's self-assessment were used to evaluate the treatment results. Twenty-one patients were subjected to a 1-year follow-up.

RESULTS

Significant improvement in melasma pigmentation was observed in the mean MI and mMASI score; both were significantly reduced (p < 0.0001). Significant erythema reduction was achieved (p < 0.001). In total, 70% of participants rated the laser as a method that met their expectations for treating melasma. Clinical follow-up after one year showed that the reduced melasma effect was still maintained. Patients also noticed improved skin conditions (radiance, smoothness, brightness, hydration, regeneration). No serious adverse effects were observed.

CONCLUSIONS

Low-fluence 1064 nm QSNY laser is an effective, safe, and noninvasive method with long-term results in melasma treatment. QSNY (1064 nm) improves the condition of melasma patients with erythema.

Treatment of facial and non-facial lentigines with a 730 nm picosecond titanium: Sapphire laser is safe and effective

Objective

A 730 nm picosecond‐domain laser was developed to improve the clearance of pigmented lesion and reduce adverse events. This study assessed the safety and efficacy of this system for the clearance of lentigines and explores how the short picosecond pulses interact with tissue via histology.

Study Design and Methods

Twenty subjects with Fitzpatrick skin types II–IV were enrolled in this prospective, IRB‐approved study. Four treatments were administered using a 730 nm picosecond‐domain laser. Pre‐ and posttreatment photos were assessed by blinded reviewers at 4‐ and 12‐week follow‐up visits, using a 5‐point clearance scale. Subject satisfaction was measured using a 5‐point scale. Investigator Global Improvement Score (IGIS) was performed at the 4‐ and 12‐week follow‐up visits, using an 11‐point clearance scale. Subject pain level was measured using an 11‐point scale (no pain [0], extreme pain [10]). Histology of 730 and 532 nm picosecond pulses was compared with 755 and 532 nm nanosecond pulses.

Results

Sixteen subjects with a total of 118 discontinuous treatment areas, each comprised of 1–20 lesions, completed all study visits. Thirty body regions were studied, including arms (6), hands (16), scalp (1), forehead (2), face (3), and back (2). Spot sizes ranging from 2 to 5 mm diameters were used with fluences ranging from 0.8 to 4.0 J/cm². Mean pain score was 3.6 of 10 for all four treatments. Ninety‐nine percent of randomly paired 4‐week posttreatment images and 100% of 12‐week posttreatment images were correctly identified from their respective baseline images by three blinded reviewers. Mean IGIS demonstrated scores of 6.7 and 7.0 at 4‐ and 12‐week follow‐up visits, respectively. At the 4‐ and 12‐week follow‐up visits, 76% and 73% of subjects, respectively, were satisfied to highly satisfied. The mean clearance score for all 118 treatment areas was 3 of 4 in follow‐up visits. At 12‐week follow‐up, 36% of 118 treatment areas had a clearance score of 4, and 38% had a clearance score of 3. Post treatment, there was typical erythema, edema, dryness, crusting, and itching but negligible purpura, no pinpoint bleeding, blistering or scarring, and no significant hyperpigmentation or hypopigmentation. Histology showed diffuse, focal epidermal vacuolization ~5–10 µm in diameter and mild extravasation of erythrocytes with 730 nm picosecond pulses, while diffuse epidermal vacuolization was observed with coalescence of vacuoles (~20–100 µm), junctional clefting and mild extravasation of erythrocytes with 755 nm nanosecond pulses. Picosecond pulses of the wavelength of 532 nm produced diffuse, focal epidermal vacuolization and larger dermal vacuoles to depths of 500 µm, while 532 nm nanosecond pulses produced diffuse epidermal vacuolization with coalescence of vacuoles and marked dermal hemorrhage.

Conclusion

This study demonstrated the potential of a new 730 nm picosecond‐domain laser for the clearance of lentigines. The results showed good clearance with no adverse events and good subject satisfaction in patients with skin type II–III. Additional studies need to be conducted on darker skin types. The histopathologic findings demonstrate that the picosecond 730 nm laser produces excellent selectivity for pigment with minimal disruption of the dermal–epidermal junction and may therefore reduce healing times and the risk of adverse events.