Logistic Regression Model Using Scheimpflug-Placido Cornea Topographer Parameters to Diagnose Keratoconus
Table 3
Receiver operating characteristic (ROC) analysis of the parameters where AUROC values are less than 0.9 95% confidence interval.
Parameter
AUROC
SE
Lower
Upper
Cut-off value
Sensitivity (%)
Specificity (%)
Summary indices
TCT r (mm)
0.590
0.036
0.518
0.661
0.63
48.8
68.3
Apex r (mm)
0.616
0.037
0.544
0.688
1.50
78.4
50
AD (mm)
0.630
0.035
0.560
0.699
3.28
53.6
66.7
CV (mm3)
0.821
0.027
0.769
0.874
56.25
77.6
73.3
Keratometry readings
Sim-K1 (D)
0.746
0.031
0.685
0.807
43.93
53.6
86.7
Sim-K2 (D)
0.873
0.022
0.829
0.917
45.32
79.2
81.7
Anterior Ø = 3 mm K1 (D)
0.779
0.029
0.722
0.836
43.99
56.8
88.3
Anterior Ø = 5 mm K1 (D)
0.748
0.031
0.687
0.810
44.05
53.6
89.2
Anterior Ø = 5 mm K2 (D)
0.879
0.022
0.836
0.922
45.32
80
81.7
Posterior Ø = 3 mm K1 (D)
0.713
0.036
0.642
0.785
−6.23
59.2
95.8
Posterior Ø = 5 mm K1 (D)
0.713
0.035
0.644
0.782
−6.27
54.4
96.7
Posterior Ø = 5 mm K2 (D)
0.886
0.023
0.840
0.932
−6.58
82.4
85.8
Shape indices
Anterior rf (D)
0.802
0.029
0.745
0.858
44.04
63.2
88.3
Anterior Q
0.784
0.031
0.723
0.844
0.785
73.6
77.5
Posterior rf (D)
0.864
0.026
0.814
0.914
−6.31
71.2
98.3
Posterior Q
0.796
0.031
0.736
0.856
0.495
72.8
83.3
Aberrations
Total
OPD (µm)
0.871
0.024
0.825
0.917
1.30
86.4
81.7
Astigmatism Z (2, ±2) (µm)
0.808
0.029
0.752
0.864
1.10
76
79.2
Spheric Z (4, 0) (µm)
0.575
0.039
0.498
0.652
0.205
39.2
90.8
Anterior
OPD (µm)
0.881
0.022
0.837
0.925
1.475
85.6
85
Astigmatism Z (2, ±2) (µm)
0.809
0.028
0.755
0.864
1.285
72.8
80.8
Spheric Z (4, 0) (µm)
0.638
0.038
0.563
0.713
0.215
44
96.7
Posterior
Astigmatism Z (2, ±2) (µm)
0.842
0.028
0787
0.898
0.245
73.6
95
Spheric Z (4, 0) (µm)
0.897
0.022
0.854
0.939
0.035
75.2
93.3
Residual HOAs (µm)
0.877
0.023
0.832
0.922
0.255
81.6
83.3
AUROC: area under the ROC curve; SE: standard error; Apex r = the distance of apex to the central cornea; AD = the depth of anterior chamber; CV = corneal volume; Sim-K1 = simulated flat keratometry; Sim-K2 = simulated steep keratometry; K1 = flat keratometry; K2 = steep keratometry; rf = apical radius of the flattest meridian of the aspherotoric surface in 4.5 mm zone of the cornea; Q = mean asphericity in 4.5 mm zone of the cornea; OPD OPD = total wavefront error; HOAs = higher-order aberrations.
