Journal of Ophthalmology

Research Article

Rotating Scheimpflug Imaging Indices in Different Grades of Keratoconus

Table 2

AUROC of all indices when differentiating all grades of KC collectively from normal corneas.


Indices	AUROC	SEM	95% CI

Curvature indices

Central 3 mm
Mean radius of curvature of anterior 3 mm	0.885	0.03	0.828 to 0.928
Mean radius of curvature of posterior 3 mm	0.882	0.0307	0.824 to 0.925
Mean eccentricity of the anterior surface	0.811	0.039	0.745 to 0.866
Using BFS
Radius of curvature of the 8 mm anterior BFS	0.812	0.035	0.747 to 0.867
Radius of curvature of the 9 mm anterior BFS	0.776	0.0374	0.707 to 0.835
Radius of curvature of the 7 mm posterior BFS	0.841	0.0323	0.779 to 0.892
Radius of curvature of the 8 mm posterior BFS	0.784	0.037	0.712 to 0.856
Radius of curvature of the 9 mm posterior BFS	0.746	0.038	0.671 to 0.821
Using BFTE
Flattest radius of curvature of the 7 mm posterior BFTE	0.829	0.0344	0.765 to 0.882
Steepest radius of curvature of the 7 mm posterior BFTE	0.895	0.0298	0.840 to 0.936
Eccentricity of the 7 mm posterior BFTE	0.757	0.0402	0.687 to 0.818
Flattest radius of curvature of the 8 mm posterior BFTE	0.834	0.034	0.770 to 0.885
Steepest radius of curvature of the 8 mm posterior BFTE	0.895	0.0298	0.840 to 0.936
Eccentricity of the 8 mm posterior BFTE	0.757	0.0402	0.687 to 0.818
Flattest radius of curvature of the 9 mm posterior BFTE	0.833	0.034	0.769 to 0.885
Steepest radius of curvature of the 9 mm posterior BFTE	0.884	0.0313	0.827 to 0.927
Eccentricity of the 9 mm posterior BFTE	0.757	0.0402	0.687 to 0.818

Elevation indices

Elevation of the thinnest point from the 7 mm posterior BFS	0.971	0.0137	0.934 to 0.990
Maximum elevation from the 7 mm posterior BFS	0.916	0.0202	0.865 to 0.953
Minimum elevation from the 7 mm posterior BFS	0.908	0.0219	0.855 to 0.946
Maximum minus minimum elevation from the 7 mm posterior BFS	0.923	0.0193	0.873 to 0.957
Elevation of the thinnest point from the 7 mm posterior BFTE	0.953	0.0214	0.910 to 0.979
Maximum elevation from the 7 mm posterior BFTE	0.944	0.0161	0.899 to 0.973
Minimum elevation from the 7 mm posterior BFTE	0.91	0.0264	0.858 to 0.948
Maximum minus minimum elevation from the 7 mm posterior BFTE	0.949	0.0174	0.905 to 0.976
Elevation of the thinnest point from the 8 mm anterior BFS	0.968	0.018	0.930 to 0.989
Elevation of the thinnest point from the 8 mm posterior BFS	0.979	0.00837	0.945 to 0.995
Maximum elevation from the 8 mm posterior BFS	0.837	0.0304	0.775 to 0.889
Minimum elevation from the 8 mm posterior BFS	0.89	0.0255	0.834 to 0.932
Maximum minus minimum elevation from the 8 mm posterior BFS	0.875	0.0272	0.817 to 0.920
Elevation of the thinnest point from the 8 mm anterior BFS minus that of posterior BFS	0.961	0.0139	0.920 to 0.984
Elevation of the thinnest point from the 8 mm posterior BFTE	0.933	0.0264	0.885 to 0.965
Maximum elevation from the 8 mm posterior BFTE	0.806	0.0342	0.739 to 0.861
Minimum elevation from the 8 mm posterior BFTE	0.923	0.022	0.873 to 0.958
Maximum minus Minimum elevation from the 8 mm posterior BFTE	0.912	0.0225	0.861 to 0.950
Elevation of the thinnest point from the 9 mm anterior BFS	0.979	0.0118	0.945 to 0.995
Elevation of the thinnest point from the 9 mm posterior BFS	0.977	0.0098	0.942 to 0.994
Maximum elevation from the 9 mm posterior BFS	0.772	0.0364	0.703 to 0.832
Minimum elevation from the 9 mm posterior BFS	0.865	0.0294	0.805 to 0.912
Maximum minus minimum elevation from the 9 mm posterior BFS	0.832	0.0324	0.768 to 0.884
Elevation of the thinnest point from the 9 mm anterior BFS minus that of posterior BFS	0.952	0.0171	0.909 to 0.979
Elevation of the thinnest point from the 9 mm posterior BFTE	0.904	0.0309	0.851 to 0.943
Maximum elevation from the 9 mm posterior BFTE	0.671	0.0451	0.597 to 0.740
Minimum elevation from the 9 mm posterior BFTE	0.934	0.0204	0.886 to 0.966
Maximum minus minimum elevation from the 9 mm posterior BFTE	0.887	0.0264	0.831 to 0.930

Pachymetry indices

Apex thickness	0.897	0.0268	0.842 to 0.938
Central corneal thickness	0.878	0.0288	0.820 to 0.922
Thinnest point thickness	0.915	0.0241	0.863 to 0.952
PPI-Min	0.939	0.0208	0.893 to 0.969
PPI-Avg	0.978	0.00973	0.944 to 0.994
PPI-Max	0.987	0.00563	0.958 to 0.998
PPI-Max minus PPI-Min	0.903	0.0246	0.850 to 0.943
ART-Min	0.949	0.0183	0.905 to 0.976
ART-Avg	0.976	0.0101	0.942 to 0.993
ART-Max	0.987	0.00605	0.957 to 0.998
Horizontal decentration of the thinnest point from the apex	0.558	0.0444	0.481 to 0.633
Vertical decentration of the thinnest point from the apex	0.737	0.0397	0.666 to 0.801
Diagonal decentration of the thinnest point from the apex	0.686	0.0403	0.612 to 0.754

AUROC: area under the receiver operating characteristic curve. SEM: standard error of the mean. 95% CI: 95% confidence interval of the AUROC. BFS: best-fit sphere, BFTE: best-fit toric ellipsoid, PPI-Min: Pachymetry Progression Index-Minimum, PPI-Avg: Pachymetry Progression Index-Average, PPI-Max: Pachymetry Progression Index-Maximum, ART-Min: Ambrósio’s Relational Thickness-Minimum, ART-Avg: Ambrósio’s Relational Thickness-Average, and ART-Max: Ambrósio’s Relational Thickness-Maximum.