Corneal biomechanical characteristics in myopes and emmetropes measured by Corvis ST: a meta-analysis

Purpose To comprehensively identify the corneal biomechanical differences measured by Corvis ST between different degrees of myopia and emmetropia. Design Systematic review and meta-analysis. Methods Electronic databases, including PubMed, Embase, and Web of Science, were systematically searched for studies comparing the corneal biomechanics among various degrees of myopes and emmetropes using Corvis ST. The weighted mean differences and 95% confidence intervals were calculated. Meta-analysis was performed in high and non-high myopes and in myopes and emmetropes, respectively. Results Eleven studies were included in this study. The meta-analysis among myopes and emmetropes included 1947 myopes and 621 emmetropes, and 443 high myopes and 449 non-high myopes were included in the meta-analysis among high and non-high myopia. Myopes showed the cornea with significantly longer time at the first applanation (A1t) and lower length at the second applanation (A2L) than emmetropes. High myopes showed significantly greater A1t, velocity at the second applanation (A2v), deformation amplitude at the highest concavity (HC-DA), and peak distance at the highest concavity (HC-PD) and decreased time at the second applanation (A2t) and radius of the highest concavity (HC-R). Conclusions Corneal biomechanics is different in myopia, especially in high myopia. Compared with non-high myopes, the corneas of high myopes deformed slower during the first applanation, faster during the second applanation, and showed greater deformation amplitude, indicating greater elasticity and viscidity.