Corneal curvature and elevation for early diagnosis of keratoconus with Pentacam

Objective To investigate the change of anterior and posterior corneal curvature and corneal elevation parameters with Pentacam in discriminating between clinical keratoconus eyes,subclinical keratoconus eyes and normal eyes.Design Evaluation of diagnostic technology.Participants Sixteen patients(16 eyes) with clinical keratoconus,19 patients(19 eyes) with subclinical keratoconus,and 29 patients(29 eyes) with myopic astigmatism as control group were analyzed.Method Twelve anterior and posterior corneal curvature and corneal elevation parameters provided by Pentacam were recorded for all groups.The t test and receiver operating characteristic(ROC) curves were used and partial least squares(PLS) was used to construct models with anterior and posterior corneal curvature and corneal elevation parameters for the early diagnosis of keratoconus.Main Outcome Measures The anterior and posterior corneal curvature and corneal elevation parameters.Results There were significant differences between the clinical keratoconus group,the subclinical keratoconus group and the control group.The values of area under the curve(AUC)were all closed to 1,and the diagnosis accuracy was higher.The optimum cutoff points of maximum anterior corneal elevation above the BFS at central 5.0 mm(MaxAE5) for clinical keratoconus and subclinical keratoconus were 13.5 μm and 10 μm respectively.The maximum posterior corneal elevation above the BFS at central 5.0 mm(MaxPE5) for clinical keratoconus and subclinical keratoconus were 34.5 μm and 24.5 μm.Conclusion The anterior and posterior corneal curvature and corneal elevation parameters obtained with Pentacam might be useful for the early diagnosis of clinical and subclinical keratoconus.