Abstract
Purpose :
To determine the diurnal variations in peripapillary and macular flow density (FD), as measured using optical coherence tomography angiography (OCTA) and to elaborate on the relationship between diurnal FD, circulatory parameters and intraocular pressure (IOP) variations
Methods :
40 eyes of 40 primary open-angle glaucoma patients were drawn into this prospective cross-sectional study. The retinal microvasculature of the macula (superficial and deep layers) and optic nerve (radial peripapillary capillary (RPC)) was examined by OCTA (AngioVue®, Optovue). The mean arterial pressure (MAP) and heart rate (HR) were assessed by a carry-on blood pressure measurement system, while IOP was determined by Goldmann applanation tonometry. OCTA measurements were conducted at 08:00, 11:00, 15:00 and 20:00 over the course of two consecutive days. IOP and circulatory parameters were assessed accordingly. Diurnal variations in FD were analysed using linear mixed models.
Results :
Our results reveal a significant effect of MAP (p = 0.006) and HR (p = 0.033) on FD in the superficial layers of the macula. FD in the deep layer of the macula was shown to rise throughout the day (p < 0.001). A significant effect of HR (p = 0.010) on FD could be seen in the RPC layer of the optic nerve head. No statistically significant effect of IOP fluctuations on FD was observed.
Conclusions :
This study outlines the relationship between FD and hemodynamic parameters (MAP/HR) in primary open-angle glaucoma patients and shows diurnal fluctuations of FD in the deep retinal OCT angiogram. FD measurements are likely to further our understanding of the pathophysiology of glaucoma and might offer an advanced means of visualising and assessing the vascular component of glaucoma.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.