Anterior Scleral Thickness in Young Saudi Adults Measured Using Swept-Source Optical Coherence Tomography: Sex- and Quadrant-Specific Variations

Abstract

Purpose: To report baseline anterior scleral thickness (AST) values and evaluate regional and sex-related variation in healthy young Saudi adults using swept-source optical coherence tomography (SS-OCT). Methods: A prospective, cross-sectional study included 55 healthy Saudi adults aged 18–40 years. Participants underwent comprehensive ocular examinations to exclude pathology or significant refractive errors. AST was measured using IMAGEnet 6 software in superior, inferior, nasal, and temporal quadrants at 0 mm, 1 mm, and 2 mm from the scleral spur using the anterior segment module of swept-source OCT. Regional and sex-related differences were evaluated using a linear mixed-effects model adjusted for age and spherical equivalent. Short-term within-session intra-observer test–retest repeatability across repeated B-scan acquisitions was assessed using intraclass correlation coefficients, within-subject coefficients of variation, and Bland–Altman analysis. Results: The mean age of participants was 23.56 ± 4.61 years (34 males, 21 females). AST varied significantly according to distance and anatomical quadrant (both p < 0.001), with significant distance-by-quadrant (p < 0.001) and sex-by-distance-by-quadrant interactions (p = 0.010). The inferior quadrant generally showed greater thickness, while the superior quadrant showed lower values. Bonferroni-adjusted location-specific comparisons showed greater AST in males in the superior and temporal quadrants at both 1 mm and 2 mm from the scleral spur, whereas the remaining sex comparisons were not statistically significant. Neither age nor spherical equivalent showed a significant independent association with AST. Intra-observer ICC values ranged from 0.872 to 0.939. Conclusions: AST in young Saudi adults varies according to anatomical quadrant and distance from the scleral spur, with sex-related differences showing location-dependent patterns. These findings provide descriptive baseline data for anterior scleral morphology in this population.