Abstract
Purpose: :
To compare three screening programs for keratoconus (KC) and keratoconus suspects (KCS) with corneal height data using rotating scheimpflug corneal topography.
Methods: :
Corneal topographic analysis was performed using the Pentacam (Oculus, Wetzlar, Germany) in 36 eyes with KC, 50 that were KCS, and 50 normal controls. Three screening programs (anterior Zernike, Belin/Ambrosio, and posterior peak-to-valley value of the central 4-mm diameter) were compared for sensitivity, specificity, and the receiver operating characteristics (ROC) curve.
Results: :
The sensitivities for KC with the anterior Zernike, Belin/Ambrosio, and posterior peak-to-valley value programs were 100%, 100%, and 97%, respectively, with no significant differences among them; the sensitivities for KCS were 20%, 54%, and 50%, respectively. The Belin/Ambrosio and posterior peak-to-valley values programs were significantly (p=0.009, 0.002) better than the anterior Zernike program. The specificities with the three programs were 94%, 86%, and 98%, respectively. The highest area under the ROC curve was obtained with the posterior peak-to-valley value program.
Conclusions: :
Although corneal height data accurately discriminated KC from normal controls and the Belin/Ambrosio and posterior peak-to-valley values programs are currently more useful than the anterior Zernike program for detecting KCS, the programs must be refined to differentiate eyes with KCS from normal eyes.
Keywords: keratoconus • topography • cornea: stroma and keratocytes