Enhanced Ectasia Detection Using Corneal Tomography and Biomechanics

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/Ambrosio 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 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.