Evaluation of Keratoconous Severity with pachymetric progression indexes of Pentacam

Purpose: To evaluate Keratoconous Severity with pachymetric progression indexes of Pentacam.Methods: In this study, 76 patients were enrolled. Keratoconus severity was graded according to the Amslerkrumeich classification. The pachymetric progression indexes (PPI) derived from Pentacam were recorded and correlated with severity of keratoconus. ROC curve analyses were performed to evaluate the predictive accuracy of PPI for grading keratoconus severity. Results: The mean patient age was 25.5±6.8 years. Of all keratoconus patients, 42.1% had severity of 3, 31.6%, severity of 2, 18.4%, severity of 1 and 7.9% severity of 4. The predictive value of these indices (AUC) wasstatistically significant for discriminating grade 3 from 4 of keratoconus and it was 99.3%, 86.5%, 98.2% for PPImax, PPImin and PPIave respectively (P<0.0001). The predictive value of these indices (AUC) was statistically significant for determining the severity of keratoconus 3 from 2 and it was 87.8%, 89.7% and 94.3% for PPImax, PPImin and PPIave, respectively(P<0.0001). The predictive value of these indices (AUC) was also statistically significant for discriminating the severity of keratoconus 2 from 1 and it was 99.7%, 72.2% and 84.1% for PPImax, PPImin, and PPIave, respectively(P<0.01). Conclusion: Our study showed well that pachymetric progression indexes are capable of assessing the severity of keratoconus, and this ability is high in all three PPImax, PPImin and PPIave to determine the severity of keratoconus with a good sensitivity and specificity.