Fractal analysis is a method used to quantify the geometric branching complexity and
density of retinal vessels. This study examined the relationship of retinal vascular
fractal dimension and other retinal vascular parameters with cognitive dysfunction
in an older Asian population. Subjects aged 60 years and older from the Singapore
Malay Eye Study were selected for analysis. Retinal vascular fractal dimension (Df) and other quantitative retinal vascular parameters (branching angle, tortuosity,
and caliber) were measured based on a standardized grading protocol from photographs
of the retinal fundus using a computer-assisted program. Qualitative retinal signs
were also assessed from photographs. Cognitive dysfunction was defined as a locally
validated Abbreviated Mental Test (AMT) score ≤6/10 in participants with 0-6 years
of formal education and an AMT score ≤8/10 in those with more than 6 years of formal
education. Cognitive dysfunction was identified in 262 of the 1202 participants (21.8%).
Decreased retinal vascular Df was significantly associated with lower AMT score (P = .019). In multivariate logistic regression analysis, participants with lower retinal
vascular Df values were more likely to have cognitive dysfunction (odds ratio, 1.71; 95% confidence
interval, 1.03-2.82, comparing the lowest and highest Df quintiles). In subgroup analysis stratified for cardiovascular risk factors, this
association was present in participants with hypertension and current smokers. Other
retinal vascular signs were not associated with cognitive dysfunction. Decreased retinal
vascular Df is associated with cognitive dysfunction in older persons. Rarefaction of the retinal
vasculature may reflect similar changes in the cerebral microvasculature that may
contribute to cognitive deterioration.
Key Words
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Article info
Publication history
Published online: October 24, 2012
Accepted:
September 8,
2012
Received:
August 15,
2012
Footnotes
Supported by the National Medical Research Council (grant 0796/2003, grant STAR/0003/2008) and the Singapore Bioimaging Consortium (grant C-011/2006).
Identification
DOI: https://doi.org/10.1016/j.jstrokecerebrovasdis.2012.09.002
Copyright
© 2014 National Stroke Association. Published by Elsevier Inc. All rights reserved.
