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Discriminative ability of corneal shape and biomechanical parameters for detecting keratoconus

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Session Details

Session Title: Presented Poster Session: Cornea III

Venue: Poster Village: Pod 2

First Author: : M.Sedaghat IRAN

Co Author(s): :    H. Momeni-Moghaddam   B. Lopes   R. Ambrosio Jr        

Abstract Details


To assess the diagnostic capability of corneal shape and biomechanical parameters for distinguishing healthy from keratoconic eyes.


Sedaghat Eye Clinic, Mashhad, Iran.


One eye randomly selected from 126 patients were separated into two groups: normal (n=76), and keratoconus (n=50). Diagnosis of keratoconus was based on slit-lamp findings (e.g. Fleischer ring, Vogt striae) and abnormal topographic patterns on the sagittal (axial) front curvature map. Corneal biomechanical assessments were done using Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany) and Oculus Response Analyzer (Reichert Ophthalmic Instruments, Buffalo, NY). Corneal tomography was done using Pentacam (Oculus, Wetzlar, Germany). The discriminative ability was assessed for the parameters with a statistical significance difference on the Wilcoxon ranked-sum test using receiver operating characteristic (ROC) curves.


Statistically significant differences were observed for all parameters except peak distance (PD) at highest concavity (p=0.3). Corneal hysteresis (CH) and corneal resistance factor (CRF) had an AUC 0.902 and 0.954 respectively, sensitivity of 88.2% and 76% and specificity of 96.1% and 86%. The AUC, sensitivity and specificity were 0.973, 0.88, and 0.961 for SPA1 (stiffness parameter at first applanation), 0.983, 96% and 100% for CBI (corneal biomechanical index), and 0.993, 96% and 98.7% for the IS (inferior-superior) value. A perfect discrimination AUC of 1.0 was achieved for Belin/Ambrósio Enhanced Ectasia deviation index (BAD-D), and for the Tomograhic/Biomechanical Index (TBI).


Shape and biomechanical parameters are able to accurately distinguish normal from keratoconic corneas. However, combined parameters were more effective. Future studies should test milder ectasia cases.

Financial Disclosure:

Financial Disclosure:


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