Corneal biomechanical properties in myopic eyes evaluated via Scheimpflug imaging

Abstract

Background To investigate the biomechanical properties of the cornea in myopic eyes using corneal visualization scheimpflug technology (Corvis ST). The relationships between the biomechanical properties of the cornea and the degree of myopia were also investigated.Methods 265 eyes of 265 subjects were included. According to spherical equivalent (SE) in diopters (D), participants were divided into four groups: low myopia/control group (SE: -0.50 to -3.00D), moderate myopia group (SE: -3.00 to -6.00D), high myopia group (SE: -6.00 to -10.00D) and severe myopia group (SE greater than -10.00D). Axial length (AL), anterior segment parameters, and corneal biomechanical properties were obtained with the Lenstar LS900, Pentacam HR and Corvis ST, respectively. Results Mean (±SD) SE was -7.29±4.31D (range: -0.63 to -25.75D). Mean AL was 26.31±1.82mm (range: 21.87 to 31.94mm). Significant differences were detected within the four groups in terms of six corneal biomechanical parameters: deformation amplitude (DA), time from start until second applanation (A2-time), length of flattened cornea at the second applanation (A2-length), corneal velocity during the first and second applanation (A2-velocity), time from start to highest concavity (HC-time), and central curvature at highest concavity (HC radius). DA was positively correlated with AL ( r =0.16, P =0.009) and negatively correlated with SE ( r =-0.20, P =0.001). A2-time, A2-velocity, A2-length and HC-time were positively correlated with SE and negatively correlated with AL.Conclusions The alterations in corneal biomechanics may be associated with the degree of myopia. DA and A2-velocity may be useful corneal biomechanical indicators in patients with myopia.