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Ali Kord Valeshabad, Justin Wanek, Ruth Zelkha, Jennifer I Lim, Felix Yan-Fay Chau, Mahnaz Shahidi; Conjunctival Microvascular Hemodynamics in Diabetic Retinopathy. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):1464.
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© ARVO (1962-2015); The Authors (2016-present)
It has been reported that there is significant vasculopathy in the bulbar conjunctival microcirculation prior to development of significant diabetic retinopathy (DR). The purpose of this study was to determine alterations in bulbar conjunctival microvascular hemodynamics among control and DR subjects at different stages of retinopathy.
Conjunctival microcirculation imaging was performed in 41 subjects (eyes) that included healthy control subjects (NL, N = 15), DR subjects with no or mild retinopathy (NMDR, N = 12) and DR subjects with proliferative retinopathy (PDR, N = 14). Conjunctival venular diameter (D) and axial blood velocity (V) were measured in multiple venules in each eye by customized image analysis algorithms. Blood flow (Q) was calculated based on D and V data. Measurements were then categorized into two vessel size groups (vessel size 1 and 2), and averaged to yield 2 data points per subject. A one-way analysis of variance and post hoc analysis were performed to compare D, V and Q measurements among NL, NMDR, and PDR subjects in each vessel size group.
Mean age, gender, systolic and diastolic blood pressures, and heart rate did not significantly differ among NL, NMDR and PDR groups (P ≥ 0.2). As expected, D was larger in vessel size 2 than vessel size 1 in NL, NMDR, and PDR subjects (P < 0.001). There was no significant difference in D among NL, NMDR and PDR subjects in both vessel sizes (P ≥ 0.1). V and Q were significantly different among NL, NMDR and PDR subjects in vessel size 2 (P ≤ 0.01), but not in vessel size 1 (P ≥ 0.2). In vessel size 2, there was no significant difference in V and Q between NL and NMDR subjects (P = 0.9), while V and Q were higher in PDR subjects than in NL and NMDR subjects (P ≤ 0.03).
Conjunctival hemodynamic was not significantly altered at early stage of DR, while blood flow in large venules was increased in PDR.
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