The influence of corneal biomechanical factors on surgically induced corneal astigmatism

Abstract

To investigate the correlation between the corneal biomechanical properties of cataract patients measured by Corvis-ST and surgically induced corneal astigmatism (CSIA) derived from anterior segment swept-source OCT (CASIA2). A total of 149 eyes from 149 patients received phacoemulsification with a 2.2-mm clear corneal incision at the 135° were involved. Before surgery, all patients were examined by Corvis-ST for dynamic corneal response parameters (DCRs). The total corneal astigmatism was measured using CASIA2 before the operation and at 1 month follow-up. CSIA was obtained using Alpins vector analysis. After adjustment for age, central corneal thickness, and biomechanically corrected intraocular pressure, partial correlation analysis was used to analyze the correlation between the CSIA and DCRs. The centroid of CSIA was 0.48 D @ 43°, with a magnitude of 0.75 ± 0.44 D. The age of the patient was positively correlated with the magnitude of CSIA (r =.22, P =.009). The partial correlation analysis revealed that deformation amplitude ratio (DA ratio, r = -.17, P =.045) and integrated radius (IR, r = −.20, P =.014) were both negatively correlated with the magnitude of CSIA. The magnitude of CSIA can be expressed as:. DA ratio and IR were negatively correlated with the magnitude of CSIA in 2.2-mm cataract surgery indicating an association of increased corneal stiffness with increased magnitude of CSIA.