Figure 2. The probe PB3 is the most valid probe among the three universal bacteria probes for diagnosing bacterial keratitis. A: Comparison of standardized hybridization intensities between bacterial keratitis [B] (n = 16) and non-bacterial keratitis [C] (n = 45) for the three universal bacteria probes (PB1, PB2, and PB3). B: Determination of the signal cutoff values for the three universal bacteria probes (PB1, PB2, and PB3) based on the defined groups: true bacterial keratitis (n = 16) versus non-bacterial keratitis (n = 45). The cutoff values were obtained based on a receiver operating characteristic (ROC) curve analysis. The inserted table summarizes the performance of the cutoff values for PB1, PB2, and PB3 to differentiate bacterial keratitis and non-bacterial keratitis. AUC, area under the curve; CI, confidence interval.