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Maria Eugenia Vola Ravina, Renato Lisboa, Patricia Schimchak, Kody Kishi, Natalie Afshari, David Schanzlin; Comparison of the Ocular Response Analyzer and the Belin-Ambrósio Ectasia Display for Detecting Eyes at High Risk of Developing Ectasia After Refractive Surgery. Invest. Ophthalmol. Vis. Sci. 2013;54(15):3124.
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© ARVO (1962-2015); The Authors (2016-present)
To compare diagnostic accuracies of the Ocular Response Analyzer (ORA) and the Belin-Ambrósio Ectasia Display (BAD) with the Randleman Ectasia Risk Score (RS) in eyes undergoing refractive surgery.
Two hundred and forty-nine eyes of 136 myopic patients, with no previous ocular surgery evaluated for refractive surgery were included in the study. Before surgery, all eyes underwent a clinical examination and evaluation with Pentacam (Oculus, Wetzlar, Germany) and ORA (Reichert, Buffalo, NY). We calculate the RS for all eyes as if a laser in situ keratomileusis with a hypothetical 150 μm flap would be performed. Eyes with a RS ≥ 4 were considered to have a high risk of post-operative ectasia. Parameters included in the analysis from the ORA were keratoconus match index (KMI), corneal hysteresis (CH), and corneal resistance factor (CRF). Parameters from the BAD provided by the Pentacam included in the analysis were anterior elevation change (DF), posterior elevation (DF), pachymetric progression (DP), absolute thinnest point (DT), displacement of the thinnest point (DY), and combined index (D). These “D values” represent the standard deviation from an internal database of healthy eyes. Areas under the receiver operating characteristic curves (AUC) were calculated to summarize the diagnostic accuracy of each parameter. Logistic regression was performed for the best parameter in order to access the magnitude and direction of the association with the RS.
Eighty-seven eyes with a RS ≥ 4 were included in the group with a high risk of ectasia, whereas 162 eyes with a RS < 4 were included in the control group. The ORA parameter with the largest AUC was the CRF (0.68 ± 0.05), followed by CH (0.65 ± 0.05) and KMI (0.64 ± 0.04). The BAD parameter with the largest AUC was the DT (0.80 ± 0.04), followed by the D (0.64 ± 0.05), and the DY (0.62 ± 0.05). DT provided by the BAD performed significantly better than CRF provided by the ORA (0.80 vs. 0.68; P = 0.003). Each 1 mmHg of decrease in the CRF was associated with a 46% increase in the odds of presenting a high risk in the RS.
The absolute thinnest point provided by the BAD from the Pentacam performed better than the CRF from the ORA in detecting patients at a high risk of postoperative corneal ectasia. Larger studies may help to confirm these preliminary findings.
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