The relationship between corneal biomechanics and endothelial morphology: evidence from a Saudi cohort

BackgroundCorneal biomechanics and endothelial morphology are key to ocular stability, but their relationship in healthy adults remains understudied.MethodsIn this cross-sectional study, 122 healthy Saudi adults aged 18–40 years were examined using the Ocular Response Analyzer (ORA) to measure corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated intraocular pressure (IOPg), and corneal-compensated intraocular pressure (IOPcc). Corneal endothelial morphology and central corneal thickness (CCT) were assessed using non-contact specular microscopy, providing endothelial cell density, cell count, hexagonality, and morphometric indices. Measurements were obtained under standardized conditions. Associations between biomechanical, endothelial, and refractive variables were evaluated using ANOVA, Pearson correlation analysis, and multivariate regression models.ResultsMales showed slightly lower CH, CRF, and endothelial indices, though differences were not significant. IOPg was significantly higher in hyperopes versus myopes (p = 0.014), while no refractive group differences were observed for CH, CRF, or IOPcc. CCT correlated moderately with CH (r = 0.40, p < 0.0001), CRF (r = 0.53, p < 0.0001), and IOPg (r = 0.50, p < 0.0001), while endothelial cell number (NUM) was negatively associated with IOPg (r = −0.23, p = 0.011) and IOPcc (r = −0.21, p = 0.021). Regression confirmed CCT as the strongest predictor of ORA outcomes, whereas endothelial and refractive parameters contributed minimally. Compared with international datasets, CH and CRF values in this Saudi cohort were broadly comparable, though inter-ethnic variations were noted.ConclusionCorneal biomechanics in healthy adults are predominantly driven by central corneal thickness, with endothelial morphology exerting a secondary modulatory influence on pressure-related and viscoelastic responses. These findings provide foundational normative data with relevance for refractive surgery, glaucoma assessment, and regional screening practices.