Corneal Biomechanics Differences Between Chinese and Caucasian Healthy Subjects.

Paolo Vinciguerra,Keming Yu,Xuejun Fang,Shihao Chen,Yan Wang,Riccardo Vinciguerra,Fengju Zhang,Robert Herber,Ji Bai,Xingtao Zhou,Frederik Raiskup

doi:10.3389/fmed.2022.834663

Abstract

PurposeThe aim of this study was to evaluate the difference between Caucasian and Chinese healthy subjects with regards to Corvis ST dynamic corneal response parameters (DCRs).MethodsTwo thousand eight hundred and eighty-nine healthy Caucasian and Chinese subjects were included in this multicenter retrospective study. Subsequently, Chinese eyes were matched to Caucasians by age, intraocular pressure (IOP), and Corneal Thickness (CCT) using a case-control matching algorithm. The DCRs assessed were Deformation Amplitude (DA) Applanation 1 velocity (A1v), integrated radius (1/R), deformation amplitude ratio (DAratio), stiffness parameter at applanation 1 (SPA1), ARTh (Ambrósio's Relational Thickness to the horizontal profile), and the novel Stress Strain Index (SSI).ResultsAfter age-, CCT-, and IOP- matching, 503 Chinese were assigned to 452 Caucasians participants. Statistical analysis showed a statistical significant difference between Chinese and Caucasian Healthy subjects in the values of SPA1 (p = 0.008), Arth (p = 0.008), and SSI (p < 0.001). Conversely, DA, A1v, DAratio, and 1/R were not significantly different between the two ethnical groups (p > 0.05).ConclusionWe found significant differences in the values of the DCRs provided by the Corvis ST between Chinese and Caucasian healthy subjects.

Highlights

Ethnical differences in ocular metrics are well-known since many years and include central corneal thickness [1], corneal curvature [2], anterior chamber depth [3], and axial length [4]
The inclusion criteria of this study were the existence in the database of a Corvis ST and Pentacam exam, a Belin Ambrosio Enhanced Ectasia Index total deviation (BADD)
The main finding of this study was the evidence that there is a significant difference in the values of the DCRs of the Corvis ST between Chinese and Caucasian population, more in details SPA1 and SSI which are pure biomechanical parameters and Arth which measures the thickness profile in the temporalnasal direction

Summary

Introduction

Two instruments are commercially available to measure corneal biomechanics, the Ocular Response Analyzer (ORA, Reichert Inc., Depew, NY) [16] which measures corneal deformation during a bi-directional applanation method induced by an air jet, and produces appraisals of corneal hysteresis and corneal resistance factor, together with a set of 36 waveform-derived parameters [17,18,19]. The Corvis ST (OCULUS Optikgeräte GmbH; Wetzlar, Germany) evaluates the reaction of the cornea to an air puff via an ultra-high speed (UHS) Scheimpflug camera, and uses the acquired image sequence to generate estimates of IOP and deformation response parameters (DCRs) [20]. The native software of the Corvis ST includes normative values for each DCRs which were derived from a mixed south American and Caucasian population [21]. Very few population studies have been published with regards to DCRs values in other ethnical populations [22,23,24] and none of them evaluated the difference between two different ethnical groups

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