403 RETINAL MICROVASCULAR GEOMETRIC PARAMETERS AND COGNITIVE IMPAIRMENT

Abstract

Background: Although midlife hypertension may be related to the development of dementia in late life, there are conflicting findings about the role of late-life hypertension. Novel retinal imaging allows non-invasive assessment of retinal microvascular geometry that may reflect small vessel damage from hypertension. We examined these geometric parameters in relation to cognitive impairment. Methods: This study is part of the Singapore Chinese Eye Study (40–80 years). Subjects aged 60 years and over were invited to undergo clinical assessments, neuropsychological testing and brain magnetic resonance imaging. Novel retinal microvascular geometry parameters include both focal (tortuosity, branching angle, and caliber) and global (fractal dimension) features. Cognitive function was categorized into no cognitive impairment (NCI), mild cognitive impairment no dementia (mild-CIND), moderate-CIND and dementia (moderate-CIND and dementia combined into one group for analysis) using previously validated criteria. Logistic regression models were used adjusting for age and gender, and additionally for education level, hypertension, diabetes mellitus and hyperlipidemia. Results: We included 216 participants (mean age: 70.5 years); 74 persons had CIND-mild, 55 CIND-moderate and 6 dementia. Smaller retinal arteriolar and venular fractal dimension was associated with both mild-CIND (odds ratio (OR) per standard deviation decrease: 1.50; 95% CI: 1.02–2.09) and moderate-CIND/dementia (OR: 1.71; 95% CI: 1.15–2.54). Other retinal microvascular geometry parameters were not related to cognitive impairment. Adjustments for other factors did not alter these results. Conclusions: Persons with smaller retinal fractal dimension were more likely to have cognitive impairment. This association may reflect sparser cerebral vascular network in persons with cognitive impairment.