Organization of Retinal Microvessels: Assessment Using Optical Coherence Tomography Angiography

Abstract Background: The vast majority of oxygen required for outer retinal layer, including photoreceptors is provided by choriocapillaris with a little support of deep retinal capillaris. This organization may differ between individuals depending on the variability in photoreceptor density. Based on these, we evaluated the changes and interaction between the retinal capillary networks—organization of retinal microvessels—using optical coherence tomography angiography (OCTA) considering ocular perfusion pressure (OPP) and diurnal variations. Methods: Forty eyes of 40 healthy volunteers formed the sample for this cross-sectional study. Mean arterial pressure (mAP), OPP, and OCTA measures were noted at two different time points on a single day. Results: The mAP, OPP, superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris (CC) perfusion values showed no diurnal change (p>0.05). When compared the mAP and OPP with the SCP, DCP, and CC perfusion measurements, there was no significant relation between them (p>0.05). There was a significant moderate positive correlation between DCP and CC values in both morning and afternoon (r=0.422; p=0.007, r=0.493; p=0.001, respectively). Conclusion: The DCP and CC perfusion values show a significant moderate positive correlation. This correlation may suggest the role of DCP in the maintenance of oxygen homeostasis in outer retinal layers.