Repeatability of Optical Coherence Tomography Angiography Measurements in Patients with Retinal Vein Occlusion

Purpose: To analyze the repeatability of vessel density (VD) measurements and manual foveal avascular zone (FAZ) measurementsusing optical coherence tomography angiography (OCTA) in patients with retinal vein occlusion (RVO) without macularedema. Methods: The study population consisted of patients with RVO and central macular thickness <300 μm. For each subject,measurements were performed twice with a 5-minute interval. The intraclass correlation coefficient (ICC) and coefficient ofvariation (CV) were calculated to analyze the repeatability of results obtained with the OCTA device. To identify factors relatedto repeatability, we performed Pearson correlation analyses based on the CV of potential factors. Results: A total of 48 eyes were included in the study. The ICCs of the VDs in superficial capillary plexus (SCP) and the deepcapillary plexus (DCP) were 0.748 and 0.665, respectively, and the CVs of the VDs in SCP and DCP were 9.1% and 12.6%, respectively. The ICCs associated with the FAZ of the superficial layer (SFAZ) and that of the deep layer (DFAZ) were 0.965 and0.956, respectively, and the CV of the SFAZ and DFAZ were 8.8% and 9.7%, respectively. From Pearson correlation analyses,OCTA quality was significantly correlated with the CV of the VDs of SCP and DCP. However, there were no variables that weresignificantly correlated with the CV of SFAZ and DFAZ, including OCTA quality. Conclusions: VD measurements in the SCP layer using OCTA exhibited good repeatability, and VD measurements in the DCPlayer exhibited relatively low repeatability compared to that of SCP layer measurements in patients with RVO without macularedema after treatment with bevacizumab. Manual measurement of the FAZ area in both SCP and DCP layers resulted ingood repeatability. In addition, the repeatability of VD measurements in SCP and DCP layers was correlated with OCTA imagequality.