Retinal Blood Flow Biomarkers in Healthy Human Subjects Measured with Clinical Doppler Optical Coherence Tomography

Abstract

Purpose : Doppler optical coherence tomography (DOCT) holds the promise of measuring retinal blood flow (RBF) biomarkers such as average blood velocity, vessel diameter, and flow volume within a single cardiac cycle. Using a recently developed DOCT, we investigated whether there is a difference in RBF biomarkers between the superotemporal and inferotemporal retinal vessels of healthy human eyes.

Methods : Eighteen eyes of 18 healthy subjects, 24 to 61 years old (mean 39 ± 12 years) were included in a cross-sectional study. Vessel diameter (D), average velocity (V) and retinal blood flow (RBF) measurements were assessed at the primary artery (TA) and vein (TV) of the superotemporal (ST) and inferotemporal (IT) arcades using a prototype DOCT flowmeter (3D OCT-1 (Maestro2); Topcon Corp., Tokyo, Japan). Median parameter values from 3 measurements acquired at the same location and similar Doppler angle, were used to ensure reliability and accuracy. RBF biomarkers from the superotemporal and inferotemporal arcades were compared using non-parametric independent t-tests. The association between RBF and D in both arteries and veins was assessed using Spearman rank correlation coefficient. A p-value <0.05 was considered statistically significant.

Results : Comparison of retinal blood flow biomarkers between the ST and IT vessels showed no significant differences. The V (mm/seg), RBF (μL/min), and D (μm) at the ST and IT arteries and veins are shown in Table 1. RBF and D were slightly higher in the inferotemporal region of the retina. Positive correlations were found between RBF and D in arteries (Figure 1A, r= 0.38; p= 0.014) and veins (Figure 1B, r= 0.46; p= 0.002).

Conclusions : DOCT is capable of consistent measurement of retinal blood flow biomarkers in healthy subjects, supporting its potential as a clinical tool for the evaluation of retinal blood flow. Establishing normative RBF values with this technology, as provided in this study, will be important for confirming its clinical utility for pathological assessment of conditions such as glaucoma, diabetes, and other retinal vasculopathies.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.