Breaking The Gender Barrier In Keratoconus: A Dynamic Scheimpflug Biomechanical Analysis
Published 2026 - 44th Congress of the ESCRS
Reference: FP06.15 | Type: Free paper | DOI: 10.82333/05mq-h968
Authors: Dr Raheleh Moravej* 1 , Mr Milad Naseri 1 , Dr Farhad Nejat 2 , Mr Reza Ahmadi choubdar 3
1Rehabilitation Research Center, Department of Optometry, School of Rehabilitation Sciences, Iran University of Medical Sciences,Tehran,Iran, Islamic Republic Of, 2Vision Health research center,Tehran,Iran, Islamic Republic Of, 3Specservers optitions,Deal,United Kingdom
Purpose
To assess whether sex-related differences exist in corneal biomechanical indices in keratoconus and to determine whether gender-specific thresholds are necessary for accurate diagnosis and ectasia risk assessment.
Setting
Multicenter cross-sectional comparative study
Methods
In this multicenter cross-sectional study, 436 eyes of 248 keratoconus patients (233 male, 203 female) underwent biomechanical assessment using the Oculus Corvis ST. Evaluated parameters included SSI, SP-A1, DA Ratio, Integrated Radius, A1 Velocity, biomechanically corrected IOP (bIOP), Corvis Biomechanical Index (CBI), and Tomographic Biomechanical Index (TBI). Tomographic data (Kmax, CCT) were obtained using Pentacam HR. Disease severity was classified according to Amsler–Krumeich staging. Analysis of covariance (ANCOVA) was performed to compare parameters between sexes while adjusting for age and disease stage. Secondary analyses included correlation assessment and subgroup analysis by severity stage.
Results
Mean age was 39.3±9.8 years, with males younger than females (37.8 vs 40.7 years; P=0.02). Disease stage distribution differed significantly (P=0.033), with milder stages more frequent in males and moderate stages in females. After adjusting for age and disease severity, no significant sex differences were found in SSI, SP-A1, DA Ratio, Integrated Radius, CBI, TBI, Kmax, or CCT (all P>0.05). Small but statistically significant differences were observed in A1 Velocity (0.16 vs 0.15 m/s; P=0.036) and biomechanically corrected IOP (14.1 vs 14.4 mmHg; P=0.018). Expected associations were noted between SSI and CCT (r=0.24), DA Ratio and Kmax (r=0.23), and SP-A1 and disease stage (r=-0.28) (all P<0.001).
Conclusions
Advanced corneal biomechanical indices appear largely independent of sex in keratoconus after controlling for disease severity. These findings support the use of unified diagnostic thresholds for SSI, CBI, and TBI in both male and female patients, simplifying clinical interpretation and improving consistency in ectasia detection and screening. The observed difference in disease stage distribution between sexes suggests that previously reported biomechanical disparities may reflect severity at presentation rather than intrinsic sex-related properties. This has direct implications for refractive surgery screening, reinforcing that gender-specific adjustments to biomechanical indices are unlikely to enhance diagnostic accuracy.