# Quantitative Evaluation of the Effectiveness of Erbium Glass Laser Therapy for Acne Scars
## 4 Discussion  
The study demonstrated the efficacy of 1550 nm erbium glass laser therapy in reducing the appearance of atrophic acne scars through significant improvements in various skin parameters. Each of these improved parameters provides insights into the mechanisms by which the therapy contributes to scar reduction and enhances the overall condition of the skin. There are reports on the effectiveness of the erbium glass laser in reducing acne scars; however, the assessment methods used in these studies were qualitative rather than quantitative. In the study by [PERSON] et al., 2009, 1550 nm laser therapy on acne scars was evaluated. The patients underwent three treatment sessions at six-week intervals, with the laser parameters set to 30-32 mJ pulse energy and a density of 300-350 spots/cm\({}^{2}\). The results demonstrated significant improvement, particularly for rolling-type scars, with average improvement ratings of 2.51 to 2.88 on a 4-point scale, indicating a noticeable reduction in scar appearance and enhanced skin texture. In the study by [PERSON] et al., 2009, the assessment of treatment efficacy utilized a four-point improvement scale rated by independent dermatologists who were blinded to the study. However, there was no mention of formal validation of this scale in this text, suggesting it may have been used as a subjective measure rather than a standardized or validated tool. This highlights a potential limitation in the robustness of the reported outcomes, as reliance on subjective evaluation could introduce variability in the results [17]. In the study by [PERSON] et al., the effectiveness and safety of a single-session treatment using the 1550 nm erbium-doped fractional photothermolysis system (FPS) were assessed. Each patient underwent one session with FPS at a pulse energy of 40 mJ/cm\({}^{2}\), covering 17% per cm\({}^{2}\) per pass, completing eight passes. Qualitative assessment methods included a blinded evaluation of standardized photographs by two independent dermatologists using a quartile grading scale for improvement (0 to 4) and patient-reported satisfaction levels. The clinical outcomes, evaluated three months post-treatment, showed that six out of eight participants achieved a moderate improvement (26-50%) in scar appearance, with one patient experiencing marked improvement (51-75%) and one patient showing minimal to no improvement [18]. The study by [PERSON] et al. investigated the effect of laser spot size on penetration depth using a 1550 nm Faxel(r) SR laser. Smaller spot sizes (60 \(\upmu\)m) created shallower lesions and caused more epidermal disruption, facilitating easier transepidermal elimination of dermal material. Larger spot sizes (140 \(\upmu\)m) produced deeper thermal lesions, reaching up to 700 \(\upmu\)m, while maintaining better epidermal integrity [19]. Although our study utilized a laser with a 70 \(\upmu\)m spot size, we achieved significant efficacy in the reduction of acne scars. In our study, we focused on quantitative assessment methods, enhancing the precision of therapeutic outcome evaluations. High-frequency ultrasound (HFUS) and Antera 3D(r) imaging have proven to be effective tools for the assessment of acne scars and the evaluation of treatment efficacy. Our study emphasizes the effectiveness of fractional erbium-doped glass lasers in treating atrophic acne scars, corroborating findings from previous research. [PERSON] and [PERSON] conducted a split-face study where one side of the face was treated with a fractional erbium-doped glass laser (1550 nm). Their methodology involved three treatment sessions at monthly intervals, with energy parameters ranging from 30 to 50 mJ/MTZ and coverage levels of 10-14% per pass. This approach ensured consistent and controlled treatment parameters, allowing for a robust evaluation of therapeutic efficacy. Skin texture improvement was assessed using the VISIA(r) Complexion Analysis System, which quantifies irregularities on the facial surface by generating texture scores before and after the treatment.