Purpose:
Diabetes mellitus (DM) is a micro-angiopathic disease that has been associated with decreased arterial and venous retinal blood flow velocities (RBFV). This study investigates the use of a novel non-contrast angiographic imaging device, the Retinal Functional Imager (RFI), to measure RBFV in patients with both non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR).
Methods:
Prospective, cross-sectional study. The RFI device was used to quantitatively measure peri-foveal blood flow velocities in patients with NPDR and PDR. Control data was extrapolated from a recently published study using the same device.
Results:
The study included patients with NPDR (n=10, 20 eyes) and PDR (n=10, 20 eyes). The mean age was 58 ± 9.3 years, 45% were male, 55% were non-insulin dependent. 45% of eyes had clinically significant macular edema (CSME). Mean duration of DM diagnosis was 12.3 years. Mean arterial RBFV (mm/sec) were 4.19 ± 0.99 (Control), 3.83 ± 0.53 (NPDR), and 3.36 ± 0.33 (PDR). The mean venous velocities were 3.03 ± 0.59 (Control), 2.78 ± 0.55 (NPDR), and 2.43 ± 0.35 (PDR). Compared to control eyes, PDR eyes had a lower arterial (p<.001) and venous (p<.001) velocities. When compared to NPDR eyes, PDR eyes had a lower arterial (p<.001) and venous (p<.05) velocities. Pearson's correlation coefficient analysis showed that RBFV were not closely correlated with age, gender, visual acuity, insulin use, presence of CSME, years of DM diagnosis, or history of pan-retinal or focal laser.
Conclusions:
Eyes with PDR were shown to have a slower peri-foveal retinal arterial and venous blood velocities compared to healthy controls and NPDR.Figure 1: RFI image with peri-foveal arterial (red) and venous (purple) velocities (mm/sec) in diabetic retinopathy.
Keywords: imaging/image analysis: clinical • diabetic retinopathy • blood supply