Visual impairment is a potential modifiable risk factor for prevention of Parkinson disease (PD), as a study published in EClinicalMedicine reported an association between visual impairment and the neurodegenerative disease.
While visual impairment is commonly reported among patients with PD, limited data are available on the association between visual impairment and the risk for incident PD.
The objective of the current study was to determine the association between visual impairment, defined as habitual distance visual acuity < 0.3 logarithms of the minimum angle of resolution in the better-seeing eye, and the risk for PD using data from the UK Biobank Study, which includes more than 500,000 adults aged 20-69 years from 22 centers across the UK from 2006 to 2010.
The analysis included 117,252 patients with available visual acuity data. Following exclusion of patients with a preexisting diagnosis of PD, the final cohort included 117,050 patients (mean age, 56.8 years; 54.4% women).
During a median follow-up of 5.96 years, a total of 222 patients (0.19%) were diagnosed with PD, including 16 patients (7.21%) with visual impairment and 206 patients (92.8%) without visual impairment.
After adjusting for age, gender and ethnicity, the risk for incident PD was more than 2-fold greater for those with visual impairment, compared with the risk reported for patients without visual impairment (adjusted hazard ratio, 2.28; 95% CI, 1.29-4.05; P = .005). The findings were similar in sensitivity analysis which also adjusted for depression (hazard ratio, 2.28; 95% CI, 1.29-4.04; P =.005).
The study had several limitations, including the observational design, limiting the analysis to visual acuity with no data on other visual problems on future risk for PD, missing data on the causes of visual impairment, and potential residual confounders.
“Our findings highlighted the importance of vision screening in identifying individuals at high risk of developing PD. Further studies in a distinct population are needed to corroborate our findings, and the causal nature of VI (vision impairment) and PD,” concluded the researchers.
Zhu Z, Hu W, Liao H, et al. Association of visual impairment with risk for future Parkinson’s disease. EClinicalMedicine. Published online, November 6, 2021. doi: 10.1016/j.eclinm.2021.101189.