Disagreement of Radial Peripapillary Capillary Density Among Four Optical Coherence Tomography Angiography Devices

PURPOSE: This prospective study evaluated the agreement among four optical coherence tomography angiography (OCTA) devices in the assessment of radial peripapillary capillary (RPC) density. METHODS: The study included 48 eyes of 48 subjects (14 healthy, 19 glaucomatous, and 15 non-glaucomatous optic neuropathy). Each participant was scanned using four OCTA devices in a random sequence: RTVue XR Avanti (RTVue), DRI OCT Triton (Triton), Revo NX 130 (Revo), and PLEX Elite 9000 (PlexE). All 6 × 6-mm grayscale OCTA images from each device were analyzed for RPC density using a customized algorithm. Agreement between each pair of devices was assessed using intraclass correlation coefficients (ICCs) and Bland–Altman plots. RESULTS: There was a poor correlation between devices in all comparisons (RTVue–Triton, ICC = 0.34; RTVue–Revo, ICC = 0.31; RTVue–PlexE, ICC = 0.28; Triton–Revo, ICC = 0.31; Triton–PlexE, ICC = 0.17; Revo–PlexE, ICC = 0.34). Significant proportional biases (P < 0.05) and wide limits of agreement with apparent constant biases were identified in all comparisons. The mean difference was greatest for the RTVue–Revo pair (−49.3%; 95% confidence interval [CI], −52.9 to −45.8) and smallest for the Triton–PlexE pair (−7.7%; 95% CI, −10.1 to −5.3). CONCLUSIONS: The RPC densities obtained from each device had poor inter-device agreement and significant biases and cannot be used interchangeably. TRANSLATIONAL RELEVANCE: RPC density obtained from different OCTA devices is not interchangeable; thus, the progression of optic neuropathy should be monitored using the same OCTA device.