Integration of Scheimpflug-Based Corneal Tomography and Biomechanical Assessments for Enhancing Ectasia Detection

Ambrosio, Renato Jr, Lopes, Bernardo T, Faria-Correia, Fernando, Salomao, Marcella Q, Buhren, Jens, Roberts, Cynthia J, Elsheikh, Ahmed ORCID: 0000-0001-7456-1749, Vinciguerra, Riccardo and Vinciguerra, Paolo (2017) Integration of Scheimpflug-Based Corneal Tomography and Biomechanical Assessments for Enhancing Ectasia Detection. JOURNAL OF REFRACTIVE SURGERY, 33 (7). 434-+.

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Abstract

<h4>Purpose</h4>To present the Tomographic and Biomechanical Index (TBI), which combines Scheimpflugbased corneal tomography and biomechanics for enhancing ectasia detection.<h4>Methods</h4>Patients from different continents were retrospectively studied. The normal group included 1 eye randomly selected from 480 patients with normal corneas and the keratoconus group included 1 eye randomly selected from 204 patients with keratoconus. There were two groups: 72 ectatic eyes with no surgery from 94 patients with very asymmetric ectasia (VAE-E group) and the fellow eyes of these patients with normal topography (VAE-NT group). Pentacam HR and Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany) parameters were analyzed and combined using different artificial intelligence methods. The accuracies for detecting ectasia of the Belin/Ambrósio Deviation (BAD-D) and Corvis Biomechanical Index (CBI) were compared to the TBI, considering the areas under receiver operating characteristic curves (AUROCs).<h4>Results</h4>The random forest method with leave-one-out cross-validation (RF/LOOCV) provided the best artificial intelligence model. The AUROC for detecting ectasia (keratoconus, VAE-E, and VAE-NT groups) of the TBI was 0.996, which was statistically higher (DeLong et al., P < .001) than the BAD-D (0.956) and CBI (0.936). The TBI cut-off value of 0.79 provided 100% sensitivity for detecting clinical ectasia (keratoconus and VAE-E groups) with 100% specificity. The AUROCs for the TBI, BAD-D, and CBI were 0.985, 0.839, and 0.822 in the VAE-NT group (DeLong et al., P < .001). An optimized TBI cut-off value of 0.29 provided 90.4% sensitivity with 96% specificity in the VAE-NT group.<h4>Conclusions</h4>The TBI generated by the RF/LOOCV provided greater accuracy for detecting ectasia than other techniques. The TBI was sensitive for detecting subclinical (fruste) ectasia among eyes with normal topography in very asymmetric patients. The TBI may also confirm unilateral ectasia, potentially characterizing the inherent ectasia susceptibility of the cornea, which should be the subject of future studies. [J Refract Surg. 2017;33(7):434-443.].

Item Type:	Article
Uncontrolled Keywords:	Cornea, Humans, Keratoconus, Corneal Topography, Retrospective Studies, ROC Curve, Elasticity, Adolescent, Adult, Aged, Aged, 80 and over, Middle Aged, Child, Female, Male, Young Adult, Corneal Pachymetry
Depositing User:	Symplectic Admin
Date Deposited:	12 Apr 2017 07:53
Last Modified:	19 Jan 2023 07:06
DOI:	10.3928/1081597X-20170426-02
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3006952