Retinal Vascular Fractals and Cognitive Impairment

Abstract

Background: Retinal microvascular network changes have been found in patients with age-related brain diseases such as stroke and dementia including Alzheimer's disease. We examine whether retinal microvascular network changes are also present in preclinical stages of dementia. Methods: This is a cross-sectional study of 300 Chinese participants (age: ≥60 years) from the ongoing Epidemiology of Dementia in Singapore study who underwent detailed clinical examinations including retinal photography, brain imaging and neuropsychological testing. Retinal vascular parameters were assessed from optic disc-centered photographs using a semiautomated program. A comprehensive neuropsychological battery was administered, and cognitive function was summarized as composite and domain-specific Z-scores. Cognitive impairment no dementia (CIND) and dementia were diagnosed according to standard diagnostic criteria. Results: Among 268 eligible nondemented participants, 78 subjects were categorized as CIND-mild and 69 as CIND-moderate. In multivariable adjusted models, reduced retinal arteriolar and venular fractal dimensions were associated with an increased risk of CIND-mild and CIND-moderate. Reduced fractal dimensions were associated with poorer cognitive performance globally and in the specific domains of verbal memory, visuoconstruction and visuomotor speed. Conclusion: A sparser retinal microvascular network, represented by reduced arteriolar and venular fractal dimensions, was associated with cognitive impairment, suggesting that early microvascular damage may be present in preclinical stages of dementia.

The application of retinal fundus camera imaging in dementia: A systematic review

“…Although the underlying mechanisms for its onset and development remain unclear, retinal tortuosity has been associated with hypertension, retinopathy, cerebral vessel disease, stroke, and ischemic heart disease [18,[41][42][43]. The finding of increased tortuosity in AD is in line with previous findings in stroke, hypertension, and cerebrovascular disease [40,44,45]. Reduced tortuosity has been associated with increasing risk of death from ischemic heart disease possibly resulting from endothelial dysfunction and a widespread impairment of perfusion or oxygenation in the microvasculature [42].…”

Association Between Visual Impairment and Decline in Cognitive Function in a Multiethnic Asian Population

“…26,27 The version of the AMT questionnaire used was slightly modified for the Singapore context 28 and had been validated in several population-based studies. 16,[29][30][31][32][33][34] The AMT was administered by trained study investigators to participants 60 years or older in a language of their preference. All questions were of equal weight (1 mark each), culminating in a total possible score of 10.…”

Retinal microvascular network alterations: potential biomarkers of cerebrovascular and neural diseases

“…The dementias, which are characterized by extensive and complex heterogeneity in the etiology, have received significant attention in recent years, with clinicians employing ophthalmic imaging techniques. For example, cognitive impairment has been consistently reported to be associated with retinal abnormalities in both cross-sectional and longitudinal studies (5,22,90,92,138). Changes in retinal vascular network geometry, such as venular widening and arteriolar narrowing, rarefaction of the vasculature, and suboptimal bifurcation angles and suboptimal junctional branching coefficients, have been correlated with worse cognitive functioning (16,38,61,69,92,99,102).…”