Abstract
Purpose :
Cross-sectional, observational study to investigate total retinal blood flow (TRBF) using en face Doppler optical coherence tomography (OCT) in eyes with diabetic macular edema (DME), non-proliferative diabetic retinopathy (NPDR), and proliferative diabetic retinopathy (PDR).
Methods :
TRBF was measured in 33 eyes of 18 patients with diabetic retinopathy (DR) (8 females, age 64.5±12.9 years), and 16 eyes of 12 normal control subjects (8 females, age 59.3±10.4 years), using a 1050-nm swept-source OCT prototype operating at 400-kHz axial scan rate. Volumetric data comprising 600×80 axial scans over a 1.5mm×2mm area at the optic disc was repeatedly acquired 24 times in 3.4 seconds. TRBF was automatically calculated and averaged over the cardiac cycle (Fig. 1). The patients were stratified by disease severity into mild NPDR, moderate NPDR, and severe NPDR or PDR as well as by the presence or absence of DME. Among the 13 eyes with DME, 3 were not treated prior to imaging, while other 3 received anti-VEGF only, 4 received focal laser only, and 3 received both anti-VEGF and laser.
Results :
Mean TRBF in the normal group, the DME group, and the DR without DME group was 44.4±8.3µL/min, 29.3±9.4µL/min, and 51.7±16.4µL/min, respectively (Fig. 2A). TRBF was significantly lower in the eyes with DME compared to both the normal eyes (p≤0.001, Welch’s t-test) and the DR eyes without DME (p≤0.002). Within the 20 DR eyes without DME, TRBF in the mild NPDR, moderate NPDR, and severe NPDR/PDR groups was 45.4±9.18µL/min, 49.5±19.1µL/min, and 55.4±11.7µL/min, respectively. Within the 13 eyes with DME, TRBF in the mild NPDR, moderate NPDR, and severe NPDR/PDR groups was 32.3µL/min, 30.7±10.2µL/min, and 25.2±6.2µL/min, respectively (Fig. 2B).
Conclusions :
TRBF in DR patients was measured by high-speed en face Doppler OCT. A decrease in TRBF was observed in eyes with DME compared to DR eyes without DME and normal eyes. Further investigation is merited as our observations suggest the complex nature of TRBF changes associated with DR progression.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.