Corneal biomechanics as a function of intraocular pressure and pachymetry by Dynamic Infrared Signal and Scheimpflug Imaging Analysis in normal eyes – Accepted Manuscript

Abstract: Purpose: To evaluate corneal biomechanical deformation response using Ocular Response Analyzer (ORA) and Corvis ST data.Design: Prospective Observational case control studyMethods: 1262 eyes of 795 patients were enrolled. 3 groups were established, according to the corneal compensated intraocular pressure (IOPcc), group I (10-13mmHg), group II (14-17mmHg), and group III (18-21mmHg). Each group included 3 subgroups, based on central corneal thickness (CCT), subgroup 1 (465-510㎛), 2 (510-555㎛), and 3 (555-600㎛). In addition, similar groups of CCT were divided into subgroups of IOPcc. Corneal hysteresis (CH) and corneal resistance factor (CRF) were derived from ORA. The parameters of highest concavity with the parameters of first and second applanation were recorded from Corvis ST.Results: CH and CRF, applanation time1, and radius of curvature at highest concavity showed significant differences between CCT subgroups for each IOPcc group (p < 0.0001). CH, applanation time 1, 2, and applanation velocity 2, as well as deformation amplitude (DA) showed significant differences by IOP subgroups for all CCT groups. IOPcc is correlated negatively with CH (r = -0.38, p < 0.0001). There are positive correlations of IOPcc with applanation time 1, applanation velocity 2, radius, and negative correlation with applanation time 2 (r = - 0.54, p < 0.0001), applanation velocity 1(r = -0.118, p < 0.0001) and deformation amplitude (r = - 0.362, p < 0.0001).Conclusion: ORA and Corvis ST parameters are informative in the evaluation of corneal biomechanics. IOP is important in deformation response evaluation and must be taken into consideration.