Concordance between corneal biomechanical testing and Scheimpflug tomography for keratoconus detection

RUISEÑOR VÁZQUEZ PABLO; GALLETTI JONATÁN; MÍNGUEZ NATALIA; DELRIVO MARIANELLA; FUENTES BONTHOUX FERNANDO; PFÖRTNER TOMÁS; GALLETTI JEREMÍAS GASTÓN

Orlando

Congreso; ARVO 2014 Annual Meeting; 2014

ARVO

Purpose To evaluate the concordance between Scheimpflug tomography and Ocular Response Analyser (ORA) testing in topographically unremarkable corneas for keratoconus detection Methods Observational case series of 206 eyes of 206 refractive surgery candidates evaluated with corneal topography for inclusion (only eyes with average corneal power power [ACP]≤47.75 D and corneal higher-order aberrations [HOA]≤0.650 µm) and then analyzed with Scheimpflug tomography (OCULUS Pentacam HR, Optikgeräte GmbH, Germany) and biomechanical testing (Ocular Response Analyzer, Reichert Ophathalmic Instruments, Depew, NY). Main outcome measurements were the Pentacam?s ectasia detection indices (Df, Db, Dp and D, cutoff ≥1.6) and previously validated combinations of ORA measurements (DifCRF and LF2, J Refract Surg. 2013 Sep;29(9):596-602). Statistical significance was set at p0.7 did (Dp 0.47±0.91 vs 0.99±1.10, p=0.03; D 0.94±0.85 vs 1.42±1.14, p=0.03). LF2 reached highest concordance with Dp (86.9%) and D (76.2%) with a >0.7 cutoff, and conversely, the latter showed highest concordance with LF2 (89.3% and 86.4%, respectively) with a ≥2.0 cutoff. Conclusions Striving for high sensitivity for ectasia detection by a single method comes at the cost of reduced specificity. Concordance between ORA testing and Pentacam Scheimpflug tomography is acceptable, but there is the prospect of lowering the false positive rate by combining both technologies with modified diagnostic criteria.