Diagnostic capacity of the keratoconus match index and keratoconus match probability in subclinical keratoconus.
OBJECTIVE
To evaluate the diagnostic capacity of the Ocular Response Analyzer's keratoconus match index (KMI) and keratoconus match probability (KMP) classification in keratoconus-suspect eyes.


METHODS
Department of Ophthalmology, University Clinics Saarland, Homburg, Germany.


METHODS
Comparative case series.


METHODS
The KMI and KMP parameters in keratoconus-suspect eyes and normal eyes (control group) were compared. The quantitative keratoconus percentage index was calculated for all suspect eyes. According to the thinnest corneal thickness (TCT), keratoconus-suspect eyes were divided into 2 subgroups: subgroup 1 (TCT <520 μm) and subgroup 2 (TCT >520 μm). The KMI's overall predictive accuracy was assessed using receiver operating characteristic (ROC) curves. The relationship between KMI and a series of Scheimpflug-derived keratoconus-related indices was evaluated using Spearman analysis.


RESULTS
The mean KMI was 0.41 ± 0.29 (SD) in the keratoconus-suspect group (50 eyes) and 0.94 ± 0.29 in the control group (50 eyes) (P<.001). Nonsignificant KMI differences were detected between the keratoconus-suspect subgroups (subgroup 1, 27 eyes; subgroup 2, 23 eyes) (P=.059). Nonsignificant correlations were found between Scheimpflug indices and the KMI. The KMP identified 27.65% of control eyes as keratoconus suspect and 10.71%, 28.57%, and 3.57% of keratoconus-suspect eyes as being normal, having mild keratoconus, or having moderate keratoconus, respectively. The ROC analysis for the KMI indicated a predictive accuracy of 94% (cutoff point 0.72).


CONCLUSIONS
The KMI seems to be a valuable index in the early diagnosis of keratoconus-suspect eyes. The KMP identified a significant percentage of topographically defined keratoconus-suspect eyes as normal or keratoconic.


BACKGROUND
No author has a financial or proprietary interest in any material or method mentioned.
From the Department of Ophthalmology (Labiris, Gatzioufas, Seitz), University Medical Center of Saarland UKS, Homburg/Saar, Germany; the Eye Institute of Thrace (Labiris, Giarmoukakis, Sideroudi, Kozobolis), Alexandroupolis, Greece. Electronic address: labiris@usa.net.
Georgios
G
Labiris
From the Department of Ophthalmology (Labiris, Gatzioufas, Seitz), University Medical Center of Saarland UKS, Homburg/Saar, Germany; the Eye Institute of Thrace (Labiris, Giarmoukakis, Sideroudi, Kozobolis), Alexandroupolis, Greece.
Athanassios
A
Giarmoukakis
From the Department of Ophthalmology (Labiris, Gatzioufas, Seitz), University Medical Center of Saarland UKS, Homburg/Saar, Germany; the Eye Institute of Thrace (Labiris, Giarmoukakis, Sideroudi, Kozobolis), Alexandroupolis, Greece.
Zisis
Z
Gatzioufas
From the Department of Ophthalmology (Labiris, Gatzioufas, Seitz), University Medical Center of Saarland UKS, Homburg/Saar, Germany; the Eye Institute of Thrace (Labiris, Giarmoukakis, Sideroudi, Kozobolis), Alexandroupolis, Greece.
Haris
H
Sideroudi
From the Department of Ophthalmology (Labiris, Gatzioufas, Seitz), University Medical Center of Saarland UKS, Homburg/Saar, Germany; the Eye Institute of Thrace (Labiris, Giarmoukakis, Sideroudi, Kozobolis), Alexandroupolis, Greece.
Vassilios
V
Kozobolis
From the Department of Ophthalmology (Labiris, Gatzioufas, Seitz), University Medical Center of Saarland UKS, Homburg/Saar, Germany; the Eye Institute of Thrace (Labiris, Giarmoukakis, Sideroudi, Kozobolis), Alexandroupolis, Greece.
Berthold
B
Seitz
D001696:Biomechanical Phenomena; D003315:Cornea / Q000473:pathology*; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D004548:Elasticity; D006801:Humans; D007640:Keratoconus / Q000145:classification / Q000175:diagnosis*; D011336:Probability; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical