Comparative analysis of RNFL and optic disc measurements across three OCT devices in healthy eyes: Implications for device standardization and clinical practice

PURPOSE: The study aimed to compare retinal nerve fiber layer (RNFL) and optic disc measurements obtained using three optical coherence tomography (OCT) devices-Heidelberg Spectralis, Zeiss Cirrus 5000, and Optovue Solix Essential-in healthy individuals, and to assess interdevice agreement and clinical applicability. METHODS: This prospective study involved 70 healthy participants. RNFL thickness (mean, superior, inferior, nasal, and temporal) and optic disc parameters (rim area, disc area, and vertical cup-to-disc ratio) were measured on the same day using the three OCT devices. Scans with poor quality or segmentation errors were excluded. Statistical comparisons were made using the Friedman and Wilcoxon tests, while interdevice agreement was evaluated using intraclass correlation coefficients (ICCs). RESULTS: Significant differences in RNFL thickness were found between devices in all segments ( P < 0.001). The highest RNFL thickness was observed with the Heidelberg device in the superior segment (Median: 128 µm), while the lowest was recorded with Optovue (median: 115.5 µm). Optic disc parameters, including rim area and disc area, were larger with the Optovue device, whereas the vertical cup-to-disc ratio was greater with the Zeiss device. Despite significant differences, ICC analyses indicated high interdevice agreement for RNFL (ICC = 0.97) and optic disc parameters (ICC = 0.90). CONCLUSION: Although RNFL and optic disc values differed among devices, the strong interdevice agreement indicates that OCT data remain clinically interpretable across platforms. With appropriate awareness of device-specific variability, these measurements appear reliable for patient monitoring and research, though studies in clinical cohorts are needed to clarify their relevance to optic nerve disease.