Repeatability and Reproducibility of Retinal Blood Flow Measurement Using a Doppler Optical Coherence Tomography Flowmeter in Healthy Subjects.

Purpose: To evaluate the repeatability and reproducibility of retinal blood flow (RBF) measurements in humans by using new auto-alignment and measurement software in a commercially available Doppler optical coherence tomography (DOCT) system.
Methods: The DOCT flowmeter assessed the intrasession repeatability and the intersession and interobserver reproducibility of the RBF measurements. For intrasession repeatability, the coefficients of variation (CVs) of five repeated RBF measurements were calculated at the retinal arteries and veins in 20 normal eyes of 20 healthy volunteers. For intersession reproducibility, two sets of three measurements obtained by one observer on 2 different days were compared. For interobserver reproducibility, two sets of three measurements obtained by two observers on the same day were compared. Intraclass correlation coefficients (ICCs) also were used to evaluate the repeatability and reproducibility. The relevance of the DOCT flowmeter and laser Doppler velocimetry (LDV) also was assessed.
Results: Regarding intrasession repeatability, the ICC of the RBF exceeded 0.90 in arterioles and venules (ICC: 0.994 and 0.970, respectively). The CVs of the RBF in the arterioles and venules were 6.0% ± 3.4% and 8.8% ± 5.1%, respectively. The intersession and interobserver RBF values had high reproducibility in the arterioles (ICC: 0.980 and 0.993, respectively) and venules (ICC: 0.982 and 0.986, respectively). The RBF measured with the DOCT flowmeter was correlated strongly with LDV in the arterioles (r = 0.76; P < 0.001). Conclusions: The DOCT flowmeter had good reproducibility in the arterioles and venules and precisely measured the RBF as compared to the LDV in the arterioles.