Retinal Blood Velocity and Flow in Early Diabetes and Diabetic Retinopathy Using Adaptive Optics Scanning Laser Ophthalmoscopy.

Cherilyn Mae A Palochak,Stephen A Burns,Amani A Fawzi,Jessica Song,Robert A Linsenmeier,Andrew Geng,Hee Eun Lee

doi:10.3390/jcm8081165

Abstract

Using adaptive optics scanning laser ophthalmoscopy (AOSLO), we measured retinal blood velocity and flow in healthy control eyes and eyes of diabetic patients with or without retinopathy. This cross-sectional study included 39 eyes of 30 patients with diabetes (DM) with mild non-proliferative diabetic retinopathy (NPDR) or without retinopathy (DM no DR) and 21 eyes of 17 healthy age-matched controls. Participants were imaged with a commercial optical coherence tomography angiography (OCTA) device (RTVue-XR Avanti) and AOSLO device (Apaeros Retinal Imaging System, Boston Micromachines). We analyzed AOSLO-based retinal blood velocity and flow, and OCTA-based vessel density of the superficial (SCP), deep retinal capillary plexus (DCP), and full retina. Retinal blood velocity was significantly higher in eyes with DM no DR and lower in NPDR across all vessel diameters compared to controls. Retinal blood flow was significantly higher in DM no DR and lower in NPDR in vessel diameters up to 60 μm compared to controls. When comparing flow outliers (low-flow DM no DR eyes and high-flow NPDR eyes), we found they had a significantly different retinal vessel density compared to the remaining eyes in the respective groups. Retinal blood velocity and flow is increased in eyes with DM no DR, while these parameters are decreased in eyes with mild NPDR compared to healthy age-matched controls. The similarity of OCTA vessel density among outliers in the two diabetic groups suggests an initial increase followed by progressive decline in blood flow and OCTA vessel density with progression to clinical retinopathy, which warrants further investigation.

Highlights

Diabetic retinopathy (DR) is a microvascular complication affecting 35% of patients with diabetes and is the leading cause of preventable blindness in working age adults worldwide [1,2,3]
There were no significant differences in diabetes type, disease duration, and hemoglobin A1c (HbA1c) between subjects with diabetes with and without mild non-proliferative diabetic retinopathy (NPDR)
Using adaptive optics scanning laser ophthalmoscopy (AOSLO) XT imaging, we found that blood flow in eyes with DM without DR was significantly higher than controls, contrasting with significantly decreased flow in eyes with NPDR

Summary

Introduction

Diabetic retinopathy (DR) is a microvascular complication affecting 35% of patients with diabetes and is the leading cause of preventable blindness in working age adults worldwide [1,2,3]. Color Doppler imaging (CDI) studies based on ultrasound measured the larger vessels at the optic nerve and reported mixed results for the impact of diabetes on blood flow velocity [21,22,23,24] Limitations of these techniques must be considered to attempt to resolve these conflicting findings. Doppler OCT offers non-invasive, in vivo assessment of all the major peripapillary retinal venous diameters and their blood velocity and measures the absolute total retinal blood flow from an eye [25,26] Using this technology, researchers showed that retinal blood flow is significantly decreased in eyes with severe NPDR and PDR compared to controls [27,28,29]. Doppler OCT focuses on measuring all large peripapillary vessels and does not capture small caliber vessels in the parafoveal region

Methods

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Discussion

Conclusion