Comprehensive evaluation of oculus pentacam in subclinical keratoconus and clinical keratoconus patients at different stages

Abstract: PURPOSE: To evaluate and identify the ability of the Oculus Pentacam parameters to distinguish subclinical keratoconus (SCKC) and clinical keratoconus (CKC) at different stages in normal eyes. METHODS: SCKC ( n = 28), KC Stage I ( n = 25), KC Stage II ( n = 40), KC Stage III ( n = 35), KC Stage IV ( n = 26), and normal eyes ( n = 46) were analyzed using the Oculus Pentacam HR. Comparisons between groups were assessed using Kruskal–Wallis and pairwise comparison Dunn tests. Receiver operating characteristic curves were used to determine the predictive accuracy of each parameter, as described by the area under the curve (AUC). The AUCs were compared using the DeLong method. RESULTS: The SCKC group demonstrated a notable decrease in corneal thickness compared with the normal group. Index Surface Variance (ISV) had the highest ability to distinguish SCKC from normal (AUC: 0.897, sensitivity: 78.57%, specificity: 95.74%), followed by Ambrósio-Relational Thickness (ARTmax). ISV and index vertical asymmetry showed perfect discrimination ability to distinguish KC Stage I from normal eyes. Most of the Pentacam parameters had sufficient strength to differentiate between Stage II and normal eyes. CONCLUSION: The ISV from Pentacam was the most sensitive parameter for detecting SCKC, Stage I KC, and Stage II KC. Pentacam indices related to corneal thickness may be particularly valuable for identifying early signs of corneal ectasia when no abnormalities in topography are observed.