Purpose: The purpose of the study was to evaluate the influence of the examiner's experience on the reproducibility of retinal nerve fiber layer (RNFL) measurements obtained with Cirrus optical coherence tomography (OCT) and Stratus. Methods: Fifty-one normal and glaucomatous eyes of 51 participants were included. Two examiners (1 novice, 1 experienced) obtained 2 scans using both OCTs. For quantitative measurements, Bland and Altman limits of agreement were evaluated. For qualitative classifications, [kappa] coefficients were calculated. Results: Signal strength was higher with Cirrus than with Stratus (P<0.05). Signal strength was higher in scans performed by the experienced examiner than in those carried out by the inexperienced examiner in Stratus but not in Cirrus. RNFL measurement differences between Cirrus and Stratus were influenced by the examiner for the inferior (P=0.02), superior (P<0.001), and temporal quadrants (P=0.009). The RNFL quantitative agreement of examiners was higher in Cirrus than in Stratus. The qualitative agreement ([kappa] coefficients) of both examiners in the RNFL classification were almost perfect with Cirrus (in the average, superior, and inferior quadrants), and moderate with Stratus (only in average and inferior quadrant). Conclusions: The signal strength is independent of the examiner's experience in Cirrus but not in Stratus. RNFL measurements obtained by both examiners were more reproducible with Cirrus than with Stratus. The differences in RNFL measurements between both OCTs were related to the examiner's experience in all 3 quadrants. Agreement between operators in the RNFL classification was higher with Cirrus than Stratus.

Purpose: To evaluate the frequency and characteristics of misalignments (MAs) in the retinal nerve fiber layer (RNFL) analysis protocol of spectral-domain optical coherence tomography (Cirrus) and determine factors associated with MAs. Methods: Three hundred eyes (162 normal and 138 glaucomatous eyes) were included in this cross-sectional study. The MAs were considered limited when they affected only part of the scan line, and complete (CMA) when they were observed in the entire scan line. A subgroup (153 cases) with repeated scans was analyzed to compare the RNFL thicknesses in the scans with and without CMAs. Results: Two hundred ninety-nine limited MAs were found in 140 eyes (46.7%) and 151 CMAs were found in 91 eyes (30.3%). The frequency and number of CMAs were significantly related to age (P<0.05). Seventy-two CMAs were in the measurement ring in 48 eyes, more frequently in the 3 and 9-o'clock positions (P=0.001) and the horizontal quadrants (P=0.001). Among the repeated scans, the number of cases with CMAs was similar to the first scan (P=0.32). No significant differences were found in global or quadrant RNFL thickness between scans with and without CMAs. Conclusions: CMAs were present in the first or second scans in about 30% of cases and were related to older age. CMAs were more frequently in horizontal meridians and quadrants. No differences in RNFL thickness were found between scans with and without CMAs in the same patients. Scans with CMAs in the measurement ring can be considered in the RNFL evaluation.

Purpose.: To compare the retinal nerve fiber layer (RNFL) evaluation using Cirrus optical coherence tomography (OCT) and Stratus OCT in glaucoma diagnosis. Methods.: One hundred thirty normal and 86 patients with glaucoma were included in this prospective study. The signal strengths of the OCTs were evaluated. The sensitivities and specificities of global RNFL average thickness were compared in the four quadrants and in each clock hour sector. Receiver operating characteristic (ROC) curves, areas under the ROC (AUC), and the likelihood ratio (LR) were plotted for RNFL thickness. Agreement between the OCTs was calculated by using the Bland-Altman method and kappa (¿) coefficient. Results.: Twenty-three percent of all cases examined with Stratus OCT and 1.9% examined with Cirrus OCT had a signal strength below 6 (P = 0.01). In cases with signal strengths ¿6, the mean signal strength was higher with Cirrus OCT than with Stratus OCT (P = 0.01). The RNFL measurements by Cirrus were thicker than those of Stratus OCT (P < 0.05). The AUCs were 0.829 for Stratus and 0.837 for Cirrus OCT (P = 0.706) for global RNFL average. LRs were similar in both OCTs in global RNFL classification but varied in quadrants. The widths of the limits of agreement varied between 42.16 and 97.79 ¿m. There was almost perfect agreement (¿ = 0.82) in the average RNFL classification. Conclusions.: Cirrus OCT has better scan quality than Stratus OCT, especially in glaucomatous eyes. In cases with good-quality scans, the sensitivity and specificity, and AUCs were similar. The best agreement was in the global average RNFL classification. The widths of limits of agreements exceed the limits of resolution of the OCTs.