The role of the posterior corneal parameters measured by Pentacam in subclinical keratoconus screening

Objective To estimate the role of the posterior corneal parameters measured by Pentacam in screening subclinical keratoconus.Design Retrospective case-controlled study.Participants Forty five healthy subjects(73 eyes),14 keratoconus patients (20 eyes),43 subclinical keratoconus patients(58 eyes).Methods Based TOPOLYZER and biomicroscope signs,eyes were diagnosed as subclinical keratoconus and keratoconus to compare the differnces of related posterior corneal parameters provided by Pentacam in normal eyes and subclinical keratoconus or keratoconus eyes.Main Outcome Measures Back-Diff(6 mm) max,Back-Diff(6 mm )min, Back-Difference(6 mm),Back-Rmin,Back-Astig.Results The parameters which were statistically different between normal corneas and clinical keratoconus,normal corneas and subclinical keratoconus include Back-Diff(6 mm)max(P0.001),Back-Diff(6 mm) min(P0. 001).Back-Difference(6mm)(P0.001),Back-Rmin(P0.001,0.014),Back-Astig(P0.00l,0.008).ROC curves were used to identify optimal cutoff points of posterior corneal parameters,which were statistically different in subclinical keratoconus,keratoconus and normal eyes,to maximize sensitivity and specificity in discriminating keratoconus and subclinical keratoconus from normal corneas.Conclusion Pentacam can play a role in screening subclinical keratoconus and diagnosing keratoconus.