Retinal vessel density correlates with cognitive function in older adults.

Purpose: We examined the associations between retinal microvascular density, cognition, and physical fitness in healthy older adults with no reported cognitive decline.
Methods: Twenty cognitively normal older adults (age: 70.3 ± 4.6 years) were recruited. Both eyes of each subject were imaged using optical coherence tomography angiography. The vessel densities of the retinal vascular network (RVN), superficial vascular plexus (SVP), and deep vascular plexus (DVP) were measured. Cognitive function was assessed using the Mini-mental state examination (MMSE) and Montreal Cognitive Assessment (MoCA), while physical performance was evaluated using the total work during the YMCA cycle ergometer test (TW-YMCA). Spearman correlations (r _s ) were computed between measures of retinal microvascular density, cognitive function, and physical performance.
Results: The MoCA was significantly correlated to vessel density of SVD (r _s  = 0.53, P = 0.02) but not RVN (r _s  = 0.39, P = 0.09) and DVP (r _s  = 0.02, P = 0.93). MoCA was not correlated with TW-YMCA (r _s  = 0.05, P = 0.83). Retinal microvascular densities were not related to TW-YMCA (r _s  = -0.05-0.18, P > 0.05). Additionally, MMSE was not related the retinal vessel densities (r _s  = -0.10-0.21, P > 0.05) and TW-YMCA (r _s  = -0.19, P = 0.41).
Conclusions: This is the first study to reveal the association between retinal vessel density and cognition as measured with MoCA in healthy older adults with no reported cognitive decline.
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