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Vienna 2018 Delegate Registration Programme Exhibition Virtual Exhibition Satellites 2018 Survey


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External validation study of the corneal tomography and biomechanical index for enhanced ectasia detection

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Session Details

Session Title: Presented Poster Session: Refractive

Venue: Poster Village: Pod 3

First Author: : R.Ambrosio BRAZIL

Co Author(s): :    H. Momeni-Moghaddam   P. Padmanabhan   M. Salomao   J. Ferreira-Mendes   B. Lopes           

Abstract Details


The endorse the clinical validity of the Tomographic/Biomechanical Index (TBI), derived from Scheimpflug imaging (Pentacam HR and Corvis ST; Oculus Gmb; Wetzlar, Germany), with external validation studies from different countries.


Rio de Janeiro Corneal Tomography & Biomechanics Study Group; Department of Optometry, Zahedan University of Medical Sciences, Zahedan, Iran; Sankara Nethralaya, Chennai, India


In a retrospective study, patients from Rio de Janeiro, India and Iran were grouped considering a comprehensive ophthalmic examination and Placido’s corneal topography. Normal group (N) included 1 eye randomly selected from 312, 130, and 274 patients from Rio, India, and Iran respectively. Keratoconus group (KC) included 1 eye randomly selected from 118, 103, and 274 patients with keratoconus from Rio, India, and Iran respectively. Sixty-seven eyes fellow eyes with normal topography from patients with very asymmetric ectasia (VAE) from Rio, 75 from India and 24 from Iran were also included. Accuracy for detecting ectasia of TBI was tested.


The cutoff value of 0.61 provided 97% sensitivity and 99.5% specificity for separating N versus KC. Considering the eyes with normal topography (VAE-NT), the optimized TBI cutoff of 0.27 provided 85% sensitivity and 92.29% specificity. All eyes with VAE-NT had objectively measured front surface corneal topography.


TBI was externally validated as an tool for detecting ectasia. TBI may potentially epitomize the inherent ectasia susceptibility of the cornea.

Financial Disclosure:

... gains financially from product or procedure presented

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