OCT and OCT-angiography parameters of intraocular blood flow in healthy adults

Abstract

PURPOSE.To identify the relationship between the parameters of choroidal and retinal blood flow by optical coherence tomography (OCT) and OCT angiography (OCT-A), and the structural, hydrodynamic and systemic hemodynamic parameters in healthy adults.METHODS.The study included 42 male subjects aged 54.43±4.1 years without signs of local or systemic pathologies. The following parameters were evaluated on the RTVue-XR tomograph (USA): structural and microcirculatory parameters of the optic disc (OD) — peripapillary retinal nerve fiber layer (pRLNF) and radial peripapillary capillary plexus (RPCP); the macula — thickness, superficial capillary plexus (SCP), deep vascular complex (DVC), foveolar avascular zone (FAZ); the choroid — thickness, structure. Blood pressure was determined using the Riva–Rocci method; tonometry — by the Maklakov method. The parameters of bidirectional corneal applanation were evaluated, and perfusion and tolerance pressure were calculated.RESULTS.Negative correlations were revealed between intraocular pressure, pRNFL and capillary density of RCP (R= −0.58… −0.73); between choroid thickness, systemic blood flow, and tolerant pressure (R= −0.56… −0.72); between the thickness of the choroid and the volume of focal losses (FLV, %), as well as the OCT-A parameters of FAZ (area, perimeter, and density of foveolar vessels) (R= −0.45… −0.58). Positive correlations were found between perifoveal thickness (including ganglion complex) with the pRNFL (R=0.58–0.71), as well as with the thickness of the choroid (R=0.41–0.65). The confidence level was p≤0.001.CONCLUSION. The relationship of retinal, choroidal, micro hemodynamics parameters by OCT (choroid thickness) and OCT-A (RCC) (HD Angio Disc 4.5 protocol); area, perimeter, and vascular density of FAZ (Angio Retina 3.0 protocol) with  the parameters of systemic blood flow in healthy subjects can likely be considered as hemodynamic biomarkers in the diagnosis, monitoring, and evaluation of treatment effectiveness of any intraocular vascular process (including glaucoma).