## 4 Discussion
The statistically significant reduction in contrast and increase in homogeneity for the combined RGB images further validate the overall effectiveness of the erbium glass laser therapy. This holistic approach captures a broader range of textural changes, ensuring that both subtle and pronounced effects are accounted for. To comprehensively evaluate skin texture changes, various image analysis methods have been employed in dermatology, each with distinct advantages and limitations. GLCM is particularly effective for assessing spatial dependencies between pixel intensities, making it well-suited for quantifying scar remodeling. In medical sciences, the GLCM matrix has been used to analyze computed tomography images, determine breast tissue density, characterize the organization of fibrillar collagen and assess cellulite [24; 25; 26; 27]. However, alternative approaches offer different perspectives on texture evaluation. Local Binary Patterns (LBP), for example, encode local intensity differences into binary patterns, providing a computationally efficient and rotation-invariant method [28]. While LBP is widely used for texture classification, it lacks the ability to capture co-occurrence relationships between pixels, making it less sensitive to subtle surface changes in acne scars. Gabor Wavelet Transform (GWT) is another tool for analyzing skin texture, capable of extracting multi-scale and multi-orientation features, which makes it particularly useful for skin disease recognition [29]. However, its high computational cost and sensitivity to parameter tuning limit its routine clinical application. Similarly, Wavelet Transform (WT) has been employed for multi-resolution texture analysis, effectively distinguishing fine skin structures, but its reliance on frequency decomposition can make interpretation challenging in clinical dermatology [28]. Compared to alternative methods, GLCM demonstrates favorable performance in terms of computation time. In the comparative study by [PERSON] et al. [29], GLCM showed faster feature extraction than Gabor Wavelet Transform (GWT), which, although powerful in capturing multi-scale and multi-orientation features, was found to be computationally demanding. Our findings underscore the importance of utilizing quantitative image analysis methods, such as GLCM, in evaluating the efficacy of acne scar treatments. However, GLCM analysis can have limitations, such as its dependence on high-quality, standardized images and the need for careful parameter selection to avoid misinterpretation of textural features. These challenges highlight the necessity of robust imaging protocols and expert oversight during analysis. The integration of the GLCM method in evaluating the impact of acne scar treatments aligns with findings from [PERSON] et al. on hyperpigmentation reduction using microneedle mesotherapy [30]. Both studies underscore the significance of using precise quantitative techniques, such as the GLCM, to assess skin texture changes objectively. While the current study focuses on contrast and homogeneity improvements post erbium glass laser therapy, the methodology parallels the hyperpigmentation analysis, which showed reduced GLCM contrast and increased homogeneity after mesotherapy. This reinforces the broader applicability of the GLCM as a robust analytical tool for various dermatological treatments. Future studies could benefit from comparing these modalities to optimize approaches for complex skin conditions involving both scars and pigmentation changes. There are reports on the effectiveness of Er:glass lasers for reducing acne scars; however, most of these studies rely on measurement scales that are based on subjective evaluations by researchers [9; 10]. Noteworthy are the few studies that confirm the effectiveness of Er:glass laser therapy using objective, quantitative methods of evaluation. For example, [PERSON] et al.