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Purpose : This paper introduced a novel compatible parameter set (CPS) determined from IOP-matched scenario to recognize keratoconus in both IOP-matched and not scenarios.
Methods : A total of 335 eyes were included. Among them, 70 eyes (35 keratoconus and 35 normal eyes; pairwise matching for IOP) were used to determined CPS by forward logistics regression, 62 eyes (31 keratoconus and 31 normal eyes; pairwise matching for IOP) were used to validate CPS in IOP-matched scenario, and resting 203 eyes (112 keratoconus and 91 normal eyes; not pair matching for IOP) were used to validate CPS in IOP-unmatched scenario. To analyze its superiority, CPS was also compared with other two reported Biomechanical Indexes (aCBI 6,7 and DCR 8) in both scenarios. Receiver operating characteristic curves (ROC), accuracy, FI, sensitivity and specificity were used to access and compare the performance of these three parameter sets in both scenarios.
Results : The resulting CPS was comprised of only 3 biomechanical parameters: DA Ratio Max 1mm (DRM1), the first applanation time (AT1) and an energy loading parameter (Eload). In the IOP-matched validation, the area under ROC (AUC) reached 95.73%, with an accuracy of 95.2%, sensitivity of 93.5% and specificity of 96.8% (leave one out cross-validation). All these indicators reached 96.54%, 95.1%, 95.6% and 94.6% respectively, in the IOP-unmatched validation (leave one out cross-validation). Surprisingly, CPS performed better than other two parameter sets on a whole.
Conclusion : The parameter set determined from IOP-matched scenario indeed exhibit its superiority for differentiation of keratoconus and normal corneas, regardless of IOP-matched or not.
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