Validating the Reliability and Clinical Relevance of an Infraorbital Hollow Photonumeric Scale.

Background: Infraorbital hollowing is a facial aesthetic issue for which a broad age range of patients seek treatment. Expanding treatment options for this region warrants the development of validated tools to objectively assess infraorbital hollow (IOH) severity before and after treatment. Objectives: To validate a 4-point rating scale to assess depression of IOH, depression relative to the mid-pupillary line, and visibility of the lateral orbital rim. Methods: The IOH scale described herein was developed and subjected to live validation with a total of 73 patients representing the full range of IOH severities. Scale validation was performed by board-certified plastic surgeons and dermatologists (3 raters) over 2 rounds, 2 weeks apart. Intrarater and interrater reliabilities were used to demonstrate test-retest reliability as quantitated with percentage of agreement, weighted kappa statistic with 95% confidence interval (CI), and intraclass correlation coefficient with 95% CI. The clinical relevance of a 1-grade difference was evaluated by comparing rater assessments of 77 photo pairs with their previously determined designation as "clinically different" or "not clinically different." Results: The IOH scale demonstrated substantial to near-perfect intrarater and interrater reliabilities when utilized by trained raters to assess a diverse group of live patients. Furthermore, clinically relevant differences between grades were established, and detection of a 1-point difference could be achieved by trained evaluators using the IOH scale. Conclusions: This highly reliable, clinically relevant, and validated IOH scale provides a user-friendly, standardized grading system to objectively evaluate and track changes in infraorbital hollowing in clinical practice and research. Level of Evidence 3: