Diagnostic Utility of Corneal Parameters Measured with Pentacam Imaging in the Diagnosis of Early Keratoconus using real-world data: A Save Sight Keratoconus Registry study

To evaluate the diagnostic performance of Pentacam (Oculus) corneal tomographic parameters in differentiating early clinical keratoconus from normal corneas. Retrospective comparative study using data from the Save Sight Keratoconus Registry. Fifty-four eyes with clinically diagnosed early keratoconus (maximum keratometry [Kmax] < 48 D) and 49 normal control eyes were included. Mean ages were 31.4 years in the keratoconus group and 28.8 years in controls. Pentacam imaging was analysed and 31 tomographic parameters were extracted. Group comparisons accounted for inter-eye correlation by clustering on patient. Diagnostic performance was assessed using receiver operating characteristic (ROC) analysis, with area under the curve (AUC) calculated for each parameter. Optimal thresholds and predictive values were determined. The median Kmax in the keratoconus group was 45.1 D (interquartile range 2.5 D). Several parameters demonstrated good discrimination between groups. The Belin–Ambrósio deviation (BAD-D) showed the highest performance (AUC 0.904), followed by the keratoconus index (KI; AUC 0.836) and index of vertical asymmetry (IVA; AUC 0.831). Other indices, including pachymetric progression indices and elevation-based measures, demonstrated moderate diagnostic ability. Multiple Pentacam-derived tomographic parameters can discriminate early clinical keratoconus from normal corneas. BAD-D demonstrated the strongest diagnostic performance, with KI and IVA also providing useful discrimination. These findings support the role of corneal tomography as a practical tool for identifying early keratoconus in routine clinical settings.