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Am J Ophthalmol. 2019 Jan;197:7-16. doi: 10.1016/j.ajo.2018.08.054. Epub 2018 Sep 8.

Enhanced Ectasia Detection Using Corneal Tomography and Biomechanics.

Author information

1
Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil; Ophthalmology Department, Hospital de Braga, Braga, Portugal; Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
2
Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil; Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil; Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, São Paulo, Brazil.
3
Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil; Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil; Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, São Paulo, Brazil; Barra Vision Center, Rio de Janeiro, Brazil.
4
Hospital Garcia de Orta, Almada, Portugal.
5
Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil; Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil; Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, São Paulo, Brazil; Department of Ophthalmology, Federal University of the State of Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address: dr.renatoambrosio@gmail.com.

Abstract

PURPOSE:

To test the accuracy of the Tomographic and Biomechanical Index (TBI) for ectasia detection in an independent population from the original study.

DESIGN:

Retrospective case-control study.

METHODS:

Subjects: Patients were grouped according to clinical diagnosis including corneal topography (front-surface curvature): Normal group, including 1 eye randomly selected from 312 patients with normal corneas; Keratoconus group, including 1 eye randomly selected from 118 patients with keratoconus; a nonoperated ectatic eye from 57 patients with very asymmetric ectasia (57 eyes, VAE-E group), and the nonoperated fellow eye with normal topography (57 eyes, VAE-NT group).

MAIN OUTCOME MEASURES:

The ability of TBI to distinguish normal and ectatic corneas; and comparison with other indexes, including the Belin/Ambrósio Deviation Index (BAD-DI) and the Corvis Biomechanical Index (CBI), considering the areas under receiver operating characteristic curves (AUCs).

RESULTS:

The AUC of the TBI was statistically higher than all other tested parameters (DeLong, P < .001). Considering all cases, the cut-off value of 0.335 for the TBI provided a sensitivity of 94.4% and a specificity of 94.9% (AUC = 0.988; 95% confidence interval [CI] 0.982-0.995). Considering the VAE-NT group, optimized TBI cut-off value of 0.295 provided a sensitivity of 89.5% and a specificity of 91.0% (AUC = 0.960; 95% CI 0.937-0.983).

CONCLUSION:

The TBI was more accurate than all parameters tested for differentiating normal from ectatic corneas. The TBI may epitomize ectasia susceptibility and distinguish cases with fruste disease from true unilateral cases among the eyes with normal-topography VAE.

PMID:
30201341
DOI:
10.1016/j.ajo.2018.08.054

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