PICO LASER BUYER’S GUIDE | RESEARCH REVIEW #002
Prospective, Randomized, Evaluator-Blinded, Split-Face Study
Jia K, Zhang L, Ye D, et al. Lasers in Surgery and Medicine. 2026;58(6):447–454. DOI 10.1002/lsm.70134. PMID 41987480.
Study at a Glance
| Design | Population | Picosecond Arm | Thulium Arm |
|---|---|---|---|
| Prospective, randomized, split-face; single center; evaluator blinded | 35 Asian patients with symmetric facial atrophic acne scars | PicoCare 450; 1064 nm Nd:YAG + MLA; 450 ps; 1.0–1.2 J/cm²; 7 mm; 2 passes | Lavieen; 1927 nm sub-ablative fractional thulium; 1200–1800 μs; 10 W; 2 passes |
Executive Summary
This 2026 randomized split-face study compared two very different fractional laser strategies for atrophic acne scars: a 1064-nm picosecond Nd:YAG laser delivered through a microlens array (P-MLA) and a 1927-nm sub-ablative fractional thulium laser (FTL). Thirty-five patients completed three treatment sessions at four-week intervals, with final assessment 12 weeks after the last treatment.
The central efficacy finding is nuanced. Both sides improved significantly on the ECCA acne-scar scale, and the magnitude of ECCA improvement was not significantly different between treatments. However, blinded physicians assigned a modestly but statistically higher Global Aesthetic Improvement Scale (GAIS) score to the picosecond-treated side. The clearest practical separation was not scar-score reduction, but treatment experience and recovery: the picosecond side had less procedural pain, substantially less crusting, shorter crust duration, and lower erythema and melanin indices at final follow-up.
For a buyer or clinician, this is therefore not a simple 'picosecond wins' study. It supports comparable scar-severity improvement from both tested protocols while suggesting a meaningful comfort-and-downtime advantage for the specific 1064-nm PicoCare 450 MLA protocol. The authors explicitly warn that the results are platform-specific and should not automatically be generalized to all 1064-nm picosecond or 1927-nm thulium systems.
Treatment Protocols
| Parameter | 1064-nm P-MLA | 1927-nm FTL |
|---|---|---|
| Platform | PicoCare 450 (WONTECH) | Lavieen (WONTECH) |
| Pulse duration | 450 ps | 1200–1800 μs |
| Fluence / power | 1.0–1.2 J/cm² | 10 W |
| Spot / scan | 7 mm; 2–7 Hz | 0.8 mm scan density |
| Overlap / passes | 10%; 2 passes | 10%; 2 passes |
| Clinical endpoint | Mild erythema + pinpoint petechiae | Mild erythema + edema |
| Schedule | 3 sessions, 4 weeks apart | 3 sessions, 4 weeks apart |
Key Efficacy Findings
| Outcome | 1064-nm P-MLA | 1927-nm FTL | Interpretation |
|---|---|---|---|
| ECCA baseline | 102.86 ± 47.47 | 101.43 ± 44.89 | Comparable baseline severity |
| ECCA at 3 months | 86.86 ± 47.42 | 85.57 ± 50.54 | Both improved; no significant between-side difference |
| Within-side ECCA change | p < 0.001 | p < 0.001 | Significant improvement for both |
| Blinded physician GAIS | 2.83 ± 1.272 | 2.57 ± 1.243 | P-MLA higher; p = 0.037 |
| Patient satisfaction | 2.66 ± 1.142 | 2.80 ± 0.901 | No significant difference; p = 0.317 |
Buyer-facing interpretation: The validated scar-severity endpoint (ECCA) does not establish superior scar reduction for either modality. The blinded GAIS assessment favored P-MLA, but the numerical difference was relatively small. The more conspicuous advantage for P-MLA appeared in tolerability and recovery.
Safety, Comfort & Downtime
| Measure | P-MLA | FTL |
|---|---|---|
| Pain VAS, mean ± SD | 5.37 ± 2.545 | 6.06 ± 2.634 (p = 0.028) |
| Crusting | 40.00% | 91.43% |
| Median crust duration | 2 days | 4 days |
| Pruritus | 85.71% | 42.86% |
| Pinpoint bleeding / petechiae | 34.29% | 0% |
| Vesicles or pustules | 0% | 14.29% |
| Hyperpigmentation | 2.86% | 8.57% |
The picosecond treatment was not free of adverse effects. Petechiae or pinpoint bleeding occurred in roughly one-third of P-MLA-treated sides, and pruritus was more common on that side. Conversely, FTL produced much more frequent crusting, longer crust duration, and vesicles or pustules in 14.29% of treated sides. Reported post-inflammatory hyperpigmentation was uncommon and resolved during follow-up.
Objective Skin Measurements
At final follow-up, melanin index was significantly lower on the P-MLA side than the FTL side (30.80 ± 4.15 vs. 32.07 ± 3.16; p = 0.007). Erythema index was also lower on the P-MLA side (12.47 ± 2.56 vs. 13.70 ± 3.47; p = 0.037). Transepidermal water loss returned to baseline in both groups and did not differ between sides at final follow-up.
How the Authors Explain the Difference
The authors attribute the differing recovery profiles to the treatment mechanisms. The P-MLA approach uses focused picosecond energy to produce laser-induced optical breakdown (LIOB) and localized micro-vacuoles, whereas the 1927-nm thulium laser relies more heavily on water absorption and photothermal coagulation. This mechanistic explanation is biologically plausible and consistent with the observed recovery pattern, but the study did not include histopathology; therefore, it did not directly prove the proposed cellular or molecular mechanism.
Important Limitations
• Small sample: 35 patients completed the study.
• Single-center Asian population, limiting generalizability to other populations and skin phototypes.
• Only three treatment sessions with a 12-week post-treatment follow-up.
• No histopathological or molecular analysis to directly compare remodeling mechanisms.
• The two arms differed in wavelength, pulse domain, energy-delivery architecture and tissue interaction; this study does not isolate pulse duration as the causal variable.
• Results are specifically tied to PicoCare 450 and Lavieen. The authors caution against extrapolating them to all devices sharing the same wavelengths.
PLBG Evidence-Based Takeaway
Both tested platforms improved atrophic acne scars. On the ECCA scar-severity scale, neither treatment demonstrated superior improvement. The 1064-nm PicoCare 450 microlens-array protocol did, however, receive a higher blinded GAIS score and produced less pain, substantially less crusting and shorter recovery than the 1927-nm Lavieen protocol. The most defensible takeaway is therefore comparable scar improvement with a more favorable treatment-experience and downtime profile for the tested picosecond protocol—not universal superiority of picosecond technology.
Evidence / Editorial Rating
| Dimension | PLBG assessment |
|---|---|
| Study design | Strong — randomized, split-face, evaluator-blinded |
| Direct clinical relevance | High — head-to-head treatment comparison |
| Efficacy signal | Balanced — both effective; ECCA comparable; GAIS modestly favored P-MLA |
| Tolerability / downtime signal | Meaningful advantage for tested P-MLA protocol |
| Generalizability | Moderate-to-limited — 35 patients, single center, Asian population, specific devices |
| Platform extrapolation | Not justified beyond PicoCare 450 vs. Lavieen protocols tested |
Source & Transparency
Primary source: Jia K, Zhang L, Ye D, et al. Lasers in Surgery and Medicine. 2026;58(6):447–454. DOI: 10.1002/lsm.70134. PMID: 41987480; PMCID: PMC13371842.
Funding: National Natural Science Foundation of China; Xi'an Science and Technology Plan Project; Xi'an Jiaotong University Medical Development Fund. The authors declared no conflicts of interest.
Editorial note: This PLBG summary is an independent evidence synopsis. Numerical values and treatment parameters are taken from the published study; interpretive statements are deliberately limited to what this trial supports.