Visual impairment (VI) is associated with an increased risk of dementia, especially in patients with poor visual acuity, according to study results published in the American Journal of Ophthalmology. These results underscore the importance of visual screening and effective treatment of VI.
The study reports that the current understanding of the relationship between VI and the risk of dementia is insufficient. Previous studies may not have shown the association between VI and incidental dementia due to the small sample size, self-disclosure of visual function, focus on late-onset dementia, and bias in identifying cases of dementia. Therefore, investigators from China and Australia tried to investigate the link between VI and its severity in incident dementia.
A total of 117,187 participants (age range: 40-69 years, 54.4% women) from the UK Biobank Study (2006-2010) without baseline dementia were included. The researchers defined VI as the habitual distance visual acuity of less than 0.3 logMAR in the better seeing eye. Electronically linked hospital and death records were used to determine the dementia incidents in the participants.
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During a median follow-up time of 5.96 years, after adjusting for potential confounding factors, the presence of VI was significantly associated with a higher risk of incidental dementia (HR = 1.78, 95% CI: 1.18-2.68, P = 0.006).
The researchers observed an apparent trend between VI severity and risk of dementia (P for trend = 0.002). The highest risk of dementia was associated with severe VI (HR = 3.53, 95% CI: 1.31–9.49, P = 0.013).
This study reports several limitations. Only the relationship between the initial visual acuity and the risk of dementia was examined. Additionally, the causes for VI were not available. Finally, no causal conclusions could be drawn, and the possibility of misclassification of covariates and residual confusion cannot be excluded.
These data showed that individuals with VI are associated with a higher risk of developing incidental dementia, suggesting that VI may be a modifiable risk factor for dementia.
reference
Zhu Z, Shi D, Liao H, et al. Visual impairment and the risk of dementia: the UK biobank study. Am J Ophthalmol. Published online 22 August 2021. doi: 10.1016 / j.ajo.2021.08.010
This article originally appeared on Ophthalmology Advisor
