Table 3

Receiver operating characteristic curve analysis for each diagnostic parameter with respect to each stage of the Amsler-Krumeich classification

Anterior elevation differencePosterior elevation differenceAnterior elevationPosterior elevationMinimum pachymetryCentral pachymetryMean keratometryCylinder
All0.9770.9800.9090.8980.9230.8890.9140.796
Stage 10.9500.9660.8010.8130.8710.8330.8420.714
Stage 20.9940.9840.9470.9850.9090.8830.8890.767
Stage 31.0000.9940.9370.8550.9790.9380.9230.880
Stage 40.9740.9840.9630.9230.9570.9230.9970.858
Cut-off value6 μm14 μm4 μm7 μm504 μm521 μm44.7 D1.9 D
CTSP
2 mm
CTSP
4 mm
CTSP
6 mm
CTSP
8 mm
CTSP
10 mm
PTI
2 mm
PTI
4 mm
PTI
6 mm
All0.8350.6790.5270.5450.5270.9310.9270.906
Stage 10.7340.6060.5240.5650.5660.8840.8660.840
Stage 20.8180.6450.5610.6180.5050.9240.9230.898
Stage 30.9160.7590.6130.5830.5430.9220.9560.937
Stage 40.9070.7390.5440.5500.5600.9860.9750.960
Cut-off value514 μm556 μm616 μm694 μm801 μm4%11%24%
PTI
8 mm
PTI
10 mm
Progression indexD value
All0.8700.8640.9270.941
Stage 10.8090.7950.8690.891
Stage 20.8530.8370.9220.940
Stage 30.9230.9090.9560.976
Stage 40.9160.9530.9750.972
Cut-off value41%58%1.54.6
  • CTSP; corneal thickness spatial profile; D; dioptres; PTI; percentage thickness increase.