Ophthalmology (Eye & Ear Hospital) - Research Publications

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Author: Kawasaki, Ryo × Author: WANG, JIE × Author: Wong, Tien × End date: 2009 × Start date: 2008 ×

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    Flicker Light-Induced Retinal Vasodilation in Diabetes and Diabetic Retinopathy
    Nguyen, TT ; Shaw, J ; Kawasaki, R ; Vilser, W ; Wang, JJ ; Wong, TY ; Kreis, AJ (AMER DIABETES ASSOC, 2009-11)
    OBJECTIVE: Flicker light-induced retinal vasodilation may reflect endothelial function in the retinal circulation. We investigated flicker light-induced vasodilation in individuals with diabetes and diabetic retinopathy. RESEARCH DESIGN AND METHODS: Participants consisted of 224 individuals with diabetes and 103 nondiabetic control subjects. Flicker light-induced retinal vasodilation (percentage increase over baseline diameter) was measured using the Dynamic Vessel Analyzer. Diabetic retinopathy was graded from retinal photographs. RESULTS: Mean +/- SD age was 56.5 +/- 11.8 years for those with diabetes and 48.0 +/- 16.3 years for control subjects. Mean arteriolar and venular dilation after flicker light stimulation were reduced in participants with diabetes compared with those in control subjects (1.43 +/- 2.10 vs. 3.46 +/- 2.36%, P < 0.001 for arteriolar and 2.83 +/- 2.10 vs. 3.98 +/- 1.84%, P < 0.001 for venular dilation). After adjustment for age, sex, diabetes duration, fasting glucose, cholesterol and triglyceride levels, current smoking status, systolic blood pressure, and use of antihypertensive and lipid-lowering medications, participants with reduced flicker light-induced vasodilation were more likely to have diabetes (odds ratio 19.7 [95% CI 6.5-59.1], P < 0.001 and 8.14 [3.1-21.4], P < 0.001, comparing lowest vs. highest tertile of arteriolar and venular dilation, respectively). Diabetic participants with reduced flicker light-induced vasodilation were more likely to have diabetic retinopathy (2.2 [1.2-4.0], P = 0.01 for arteriolar dilation and 2.5 [1.3-4.5], P = 0.004 for venular dilation). CONCLUSIONS: Reduced retinal vasodilation after flicker light stimulation is independently associated with diabetes status and, in individuals with diabetes, with diabetic retinopathy. Our findings may therefore support endothelial dysfunction as a pathophysiological mechanism underlying diabetes and its microvascular manifestations.
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    Angiotensin-converting enzyme gene and retinal arteriolar narrowing: The Funagata Study
    Tanabe, Y ; Kawasaki, R ; Wang, JJ ; Wong, TY ; Mitchell, P ; Daimon, M ; Oizumi, T ; Kato, T ; Kawata, S ; Kayama, T ; Yamashita, H (NATURE PUBLISHING GROUP, 2009-12)
    The purpose of this study is to determine whether the angiotensin-converting enzyme (ACE) gene polymorphism is associated with retinal arteriolar narrowing, a subclinical marker of chronic hypertension. The Funagata Study examined a population-based sample of Japanese aged 35+ years; 368 participants had both retinal vessel diameter measurements and ACE insertion/deletion (ACE I/D) polymorphism analyses performed. Assessment of retinal vessel diameter and retinal vessel wall signs followed the protocols used in the Blue Mountains Eye Study. ACE gene polymorphisms D/D, I/D and I/I were present in 34 (9.2%), 170 (46.2%) and 164 (44.5%) participants, respectively, distributed in Hardy-Weinberg equilibrium. After multivariable adjustment, retinal arteriolar diameter was significantly narrower in subjects with the D/D genotype compared to subjects with I/D and I/I genotypes (mean difference -6.49 microm, 95% confidence interval (CI): -12.86 microm, -0.11 microm). Our study suggests that the ACE I/D polymorphism may be associated with subclinical structural arteriolar changes related to chronic hypertension.