Muller VC, et al. - In this cross-sectional study, 40 eyes were analyzed to study the diurnal fluctuations in peripapillary and macular flow density (FD) [measured by optical coherence tomography angiography (OCTA)] and also to develop the correlation between diurnal FD, circulatory parameters and intraocular pressure (IOP) variations in primary open-angle glaucoma (POAG). They observed an increase in FD in the deep layer of the macula throughout the day whereas no impact of diurnal variations was noticed on superficial macular FD and radial peripapillary capillary (RPC) FD. They noticed the significant influence of mean arterial pressure (MAP) and heart rate (HR) on superficial macular FD. A significant influence of HR was reported on FD in the RPC layer.