Objectification of Skin Surface Evenness: In Vivo Evaluation of 300 Women in Relation to Age

Skin surface evenness is one of the four emergent perceptual categories (EPCs) used to assess skin quality (SQ) in clinical and aesthetic practice. While objective measurements are essential for evaluating age-related changes and treatment outcomes, robust, site-specific baseline data remain unavailable.

This study aimed to establish the first normative reference ranges for skin surface evenness parameters in a large cohort of women, enabling objective comparison across anatomical sites and future benchmarking for individualized aesthetic treatment planning.

A total of 300 Caucasian women aged 20-69 years were assessed using the Visioscan VC 20plus at the forehead, cheek, neck, décolleté, and hand. Surface Evaluation of Living Skin (SELS) parameters-roughness (SEr), scaliness (SEsc), smoothness (SEsm), and wrinkles (SEw)-were analyzed. Pearson correlation coefficients were calculated to assess age-related changes. Age-stratified reference ranges were derived using percentile distributions.

Moderate positive correlations with age were observed for SEsm at the neck (r = 0.454, p < 0.01) and décolleté (r = 0.475, p < 0.01), and for SEw at the décolleté (r = 0.385, p < 0.05). Other parameters and regions exhibited low or negligible age correlations. Reference ranges for key parameters were defined across age groups.

This study provides the first age-based reference ranges for skin surface evenness in women, revealing site-specific aging patterns most pronounced in the neck and décolleté. These baselines enable objective evaluation of treatment efficacy and support personalized aesthetic interventions. By complementing established baselines for other EPCs, such as skin firmness, these findings contribute to a unified framework for objectively assessing and tracking skin quality across the aging spectrum.