Abstract
BACKGROUND: Fine lines under the lower eyelid are among the earliest and most prominent signs of facial aging. However, despite growing interest in noninvasive aesthetic procedures targeting this area, there is currently no validated clinical scale specifically designed to assess the severity of infraorbital fine lines. Furthermore, existing assessment tools-such as those for lateral canthal lines or infraorbital hollowing-fail to adequately capture the unique characteristics of horizontally oriented fine wrinkles in this region. AIMS: To develop and validate a novel photonumeric clinical grading tool, called the PharmaResearch Under Eyelid Fine Line Severity (PULS) scale, for the standardized assessment of infraorbital fine lines. METHODS: A total of 53 healthy adults without facial dermatologic conditions were photographed under standardized conditions. From the resulting image set, 73 photographs (53 unique and 20 duplicate images) were selected. Five board-certified dermatologists used our newly developed 5-grade photonumeric scale to independently evaluate the severity of infraorbital fine lines. Inter- and intra-rater reliability was assessed using Fleiss' and Cohen's Kappa, respectively. Agreement rates were also calculated. RESULTS: Inter-rater reliability analysis yielded a Fleiss' Kappa of 0.6114, indicating good inter-rater agreement. All raters showed perfect intra-rater reliability, with Cohen's Kappa values of 1.0000. The overall agreement rate across all evaluations exceeded 80%, supporting the reproducibility and consistency of the PULS scale. CONCLUSIONS: The PULS scale is a validated, reliable, and practical photonumeric grading tool that can address an unmet need in aesthetic dermatology by facilitating standardized evaluation of treatment outcomes for infraorbital fine lines in both clinical research and routine practice.