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. 2018 Aug 23:12:1527-1532.
doi: 10.2147/OPTH.S171827. eCollection 2018.

New corneal assessment index from the relational thickness and other OCULUS values (CAIRO Index)

Maged M Roshdy  1   2 , Sherine S Wahba  1   2 , Ramy R Fikry  2   3
Affiliations

New corneal assessment index from the relational thickness and other OCULUS values (CAIRO Index)

Maged M Roshdy et al. Clin Ophthalmol. .

Abstract

Purpose: The aim of this study was to find indices for keratoconus (KC) detection with higher sensitivity and specificity than the currently available ones with the rotating Scheimpflug imaging (Oculyzer I, Pentacam) software.

Patients and methods: Data of 103 normal and 73 KC eyes imaged by Oculyzer I, including slit-lamp examination, refraction, Scheimpflug images, and follow-up data were collected. Logistic regression was done to find new indices with higher area under receiver operating characteristic curves using the currently available ones.

Results: The Corneal Assessment Index from Relational thickness and other OCULUS Values 9 (CAIRO 9) index, deduced from the Ambrosio relational thickness-maximum and the anterior elevation at thinnest point from 9 mm best-fit sphere, and the CAIRO 8, deduced from Ambrosio relational thickness-maximum and anterior elevation at thinnest point from 8 mm best-fit sphere, have a very high area under receiver operating characteristic curves for KC detection (0.997 and 0.995, respectively).

Conclusion: New corneal assessment index is deduced with better sensitivity and specificity for KC detection.

Keywords: elevation; keratoconus; keratoconus diagnosis; keratoconus indices; pachymetry; pentacam.

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Conflict of interest statement

Disclosure The authors report no conflicts of interest in this work.

Figures

Figure 1
Figure 1
Getting the elevation of the thinnest point on mouse click at this exact point. Abbreviation: BFS, best-fit sphere.
Figure 2
Figure 2
AUROC of CAIRO indices compared with the 4 indices of highest AUROC throughout all cases. Abbreviations: ART-Max, Ambrosio’s relational thickness maximum; CAIRO, Corneal Assessment Index from the Relational thickness and other Oculus values using 9 mm BFS (CAIRO 9) and 8 mm BFS (CAIRO 8); PPI-max, pachymetric progression index maximum; AE, anterior elevation from 9 mm BFS (AE 9) 8 mm BFS (AE 8).
Figure 3
Figure 3
AUROC of CAIRO indices compared with the 4 indices of highest AUROC in differentiating early KC from normal corneas. Abbreviations: ART-Max, Ambrosio’s relational thickness maximum; AUROC, Area Under Receiver Operating Characteristic curves; CAIRO, Corneal Assessment Index from the Relational thickness and other Oculus values using 9 mm BFS (CAIRO 9) and 8 mm BFS (CAIRO 8); PPI-max, pachymetric progression index maximum; KC, keratoconus; AE, anterior elevation from 9 mm BFS (AE 9) and 8 mm BFS (AE 8).
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