The purpose of this study was to identify biomarkers that are indicative of diabetic peripheral neuropathy (DPN). From a cohort of 21 DPN and 18 controls, optic disc- and macula-centered images were taken. Sixty vascular parameters were measured using computer-assisted software. Statistically significant differences in vascular parameters between subjects with DPN and controls showed that DPN subjects could be differentiated from controls using retinal biomarkers. Statistical significance (p < 0.05) was obtained for 13 retinal features, including fractal dimension, vein width, number of 1st branching vessels, and vessel tortuosity. The reduced fractal dimensions in DPN patients indicate a deterioration of the retinal vascular architecture. The reduced total number of vessels, as well as the total number of venules, contribute to the lower fractals in the DPN patients and supports the findings of a sparser retinal vascular network for DPN subjects. A difference in standard deviation for vessel width may suggest a greater loss of vascular tone and regulation in DPN subjects. A difference in the number of 1st branching vessels in venules was observed, which may indicate that the DPN subjects had fewer numbers of these first bifurcations. This feature would also contribute to the lower fractal dimension as well as a sparser retinal vascular network. Similarly, the statistical difference in the angle of the first daughter vessel suggests that the retinal vascular architecture has deviated from its optimal flow and/or function due to the disease process. The increased difference in curvature tortuosity in the arterioles in DPN correlates with chronic hypertensive retinopathy. We found statistically significant differences in 13 out of 60 retinal vascular features (22%) between control and DPN subjects. As such, the retina reflects the widespread vascular structural abnormalities occurring in diabetic patients with DPN.
S.C. Nemeth: None. M.R. Burge: None. J. Wigdahl: None. J.C. Carmichael: None. X. Guo: None. V. Joshi: None. P. Soliz: Stock/Shareholder; Self; VisionQuest Biomedical LLC.
National Institutes of Health (R43DK104578-01)