Assessing total retinal blood flow in diabetic retinopathy using multi-plane en face Doppler optical coherence tomography

Abstract

Purpose : To assess total retinal blood flow (TRBF) in diabetic retinopathy (DR) using multi-plane en face Doppler optical coherence tomography (OCT).

Methods : A spectral OCT system (RTVue-XR) was used to scan a 2x2 mm area centered at the optic disc of human participants. Scans were repeated three times with each consisting of five consecutive volumes. Eyes were included if at least 8 of the combined 15 volumes were viable. The multi-plane en face Doppler OCT algorithm was used to generate a three-dimensional volumetric data set made of 195 en face planes. The TRBF was summed from the maximum flow values of each branching retinal vein at an optimized en face plane. Eyes with clinically diagnosed DR were grouped separately by disease severity according to the international clinical classification system. The Mann-Whitney test was used to compare flow values between DR groups and a healthy control group.

Results : A total of 70 eyes from 36 participants were scanned. Eight eyes were excluded due to poor image quality. The within-day repeatability of scans was 4.1% (coefficient of variation). There was no significant difference in the TRBF between the healthy group (46.2 ± 10.4 µL/min, mean ± population standard deviation, 28 eyes) and mild/moderate non-proliferative DR (42.1 ± 9.3 µL/min, 12 eyes). The TRBF’s from the severe non-proliferative DR (31.2 ± 9.4 µL/min, 12 eyes) and proliferative DR (20.1 ± 4.0 µL/min, 10 eyes) groups were significantly lower (p < 0.01) than that of the healthy group. TRBF was highly correlated with DR disease severity (r = -0.72, p < 0.001, Spearmen).

Conclusions : The novel multi-plane en face Doppler OCT method provided reliable measurements of TRBF in DR eyes. Retinal blood flow decreased with increasing severity of DR. This metric may be useful in the assessment of disease progression in the diabetic eye.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.