To evaluate the correlation of corneal elevation and difference elevation with severity of keratoconus

: 90 eyes of 55 keratoconus patients of different clinical stages were evaluated. Anterior and posterior corneal elevations with both conventional and enhanced best-fit spheres (using rotating Scheimpflug camera) were measured. Front and back difference elevation were extrapolated from difference map of Belin-Ambrosio enhanced ectasia display of the Scheimpflug system. Data from corneal elevations and difference elevations were correlated with maximum keratometry , minimal corneal thickness and severity of keratoconus as assessed by Amsler-Krumiech classification of keratoconus

There was a significant positive correlation between keratoconus severity and corneal elevations (anterior and posterior elevation measured with both conventional and enhanced best-fit spheres) and also between keratoconus severity and corneal elevation differences (P = .000 and r > .680 for all). Maximum keratometry (K max), Mean keratometry (K m) and all corneal elevations and difference elevations were highly correlated (P = .000 and r > .840 for all). A significant negative correlation was found between minimum corneal thickness and all corneal elevations and difference elevations

Evaluation of corneal elevation and and difference elevation data obtained from Scheimpflug corneal imaging is useful for grading severity of keratoconus