Biomechanical Evaluation of Topographically and Tomographically Normal Fellow Eyes of Patients With Keratoconus

Asroui, Lara, Dagher, Samir A, Elsheikh, Ahmed ORCID: 0000-0001-7456-1749, Lopes, Bernardo T, Roberts, Cynthia J, Assouad, Marc and Awwad, Shady T (2022) Biomechanical Evaluation of Topographically and Tomographically Normal Fellow Eyes of Patients With Keratoconus. JOURNAL OF REFRACTIVE SURGERY, 38 (5). pp. 318-325.

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Abstract

<h4>Purpose</h4>To determine the effectiveness of parameters and indices based on biomechanical measures at discriminating fellow eyes with topographically and tomographically normal corneas in patients with keratoconus from normal control corneas.<h4>Methods</h4>The study included 47 keratoconus suspect eyes, defined as the topographically and tomographically normal fellow eyes of patients with frank keratoconus in the other eye. Eyes were imaged using the Pentacam HR and Corvis ST (both Oculus Optikgeräte GmbH). Fellow eyes were then categorized as topographically/tomographically normal fellow eyes (TNF) and topographically/tomographically borderline fellow eyes (TBF). The ability of each of the Corvis Biomechanical Index (CBI), Tomographic and Biomechanical Index (TBI), stiffness parameter at applanation 1 (SP-A1), and stress-strain index (SSI) at discriminating between normal controls and keratoconus suspects was assessed.<h4>Results</h4>The TBI had the best discriminative ability with the greatest area under the receiver operating characteristic (AUROC) curve value of 0.946 for normal controls versus TBF eyes, and 0.824 for normal controls versus TNF eyes. Compared to the TBI AUROC curves, SP-A1 and CBI had AUROC curve values of 0.833 (<i>P</i> = .09) and 0.822 (<i>P</i> = .01) for normal controls versus TBF eyes, respectively, and AUROC curve values of 0.822 (<i>P</i> = .96) and 0.550 (<i>P</i> = .0002) for normal controls versus TNF eyes, respectively. The TBI had the best positive predictive value for TNF and TBF eyes, followed by CBI and SP-A1.<h4>Conclusions</h4>The TBI and the purely biomechanical parameter SP-A1 were of moderate utility in distinguishing between normal and keratoconus suspect eyes. In the absence of topographic/tomographic evidence of keratectasia, an independently abnormal biomechanical parameter may suggest an increased risk of ectasia. <b>[<i>J Refract Surg</i>. 2022;38(5):318-325.]</b>.

Item Type:	Article
Uncontrolled Keywords:	Cornea, Humans, Keratoconus, Corneal Topography, Retrospective Studies, ROC Curve, Elasticity, Corneal Pachymetry, Biomechanical Phenomena
Divisions:	Faculty of Science and Engineering > School of Engineering
Depositing User:	Symplectic Admin
Date Deposited:	25 Feb 2022 09:12
Last Modified:	01 May 2023 01:30
DOI:	10.3928/1081597X-20220225-01
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3149614