Correlation of Corneal Biomechanical Stiffness With Refractive Error and Ocular Biometry in a Pediatric Population.

Purpose: To assess the correlation between corneal biomechanical stiffness and refractive error (RE) in the pediatric population.

Methods: A total of 733 pediatric eyes were included in the study retrospectively. All eyes underwent corneal tomography (Pentacam), RE assessment, and air-puff deformation (Corvis-ST). Waveform analyses of deformation provided corneal stiffness (CS) and extraocular tissue stiffness (EOS). Eyes were subgrouped into emmetropia [manifest refraction spherical equivalent (MRSE) ∼ 0 D], hyperopia (MRSE > 0 D), myopia I (MRSE between 0 D and -3 D), myopia II (MRSE between -3 D and -6 D), and myopia III (MRSE greater than -6 D) for multivariate analyses. Ocular biometry variables [age, intraocular pressure (IOP), central corneal thickness (CCT), corneal astigmatism, anterior chamber depth, and RE] were used as covariates. The apparent elastic modulus (E) was defined as the ratio of CS and CCT.

Results: All groups had similar age, CCT, and IOP (P > 0.05). CS was the only parameter to differ between all the grades of myopia (P < 0.0001). CS was lower by 3.72%, 6.84%, and 10.68% in myopia I, II, and III eyes, respectively, relative to emmetropic eyes. EOS increased by 11.15%, 22.60%, and 28.5%, respectively. Multivariate regression revealed age, IOP, CCT, corneal astigmatism, anterior chamber depth, and RE as significant predictors of CS, with a high coefficient of regression (R = 0.66). Corneal E negatively correlated with the grade of myopia.

Conclusions: CS and EOS correlated negatively and positively with the grade of myopia, respectively. Ocular biometry variables were significant predictors of both CS and EOS. The decrease in CS was attributed to that in elastic modulus.