Visual Impairment Is More Common in Parkinson’s Disease and Is a Risk Factor for Poor Health Outcomes

Abstract

Background Visual impairment is associated with hip fracture, depression, anxiety, and dementia in the general population, and many causes of visual impairment are preventable or treatable with early detection. However, the prevalence, outcomes, and healthcare utilization patterns associated with visual impairment have not been examined in Parkinson’s disease (PD). Methods We performed a cross‐sectional analysis of all Medicare beneficiaries with complete data in 2014 and longitudinal analysis of beneficiaries with PD from 2010 to 2014. We used diagnosis and procedure codes to identify PD, visual impairment, eye exams, hip fracture, and neuropsychiatric disorders. We compared the prevalence of visual impairment using logistic regression and used Cox proportional hazards regression to examine visual impairment and incident hip fracture, depression, anxiety, dementia, and death. We also examined the frequency of eye exams in PD using repeated‐measures logistic regression. Results Among 26,209,997 Medicare beneficiaries in 2014, visual impairment was significantly more prevalent in PD (1.7%) than non‐PD (0.71%) (adjusted odds ratio, 1.60; 95% confidence interval [CI], 1.56–1.65). In a longitudinal cohort of 542,224 Medicare beneficiaries with PD, less than 60% had a yearly eye exam. Visual impairment associated with increased hazard of depression (hazard ratio [HR], 1.23; 95% CI, 1.14–1.32), anxiety (HR, 1.34; 95% CI, 1.24–1.43), dementia (HR, 1.28; 95% CI, 1.21–1.36), and death (HR, 1.49; 95% CI, 1.44–1.55). Conclusion Visual impairment is more common in PD than the general population and is associated with negative PD‐related outcomes. Understanding the mechanisms for these relationships is important for guiding future interventions to improve health outcomes in PD. © 2020 International Parkinson and Movement Disorder Society

Sequence of clinical and neurodegeneration events in Parkinson’s disease progression

“…Early involvement of visual dysfunction is interesting—particularly so because it precedes retinal abnormality and the earliest cortical neurodegeneration. This is consistent with emerging data that suggest visual changes are an early manifestation or even a precursor of cognitive change in Parkinson’s disease ( Williams-Gray et al , 2013 ; Anang et al , 2014 ), including some of our own work on the discovery cohort ( Leyland et al , 2020 ) and more recently showing, in very large cohorts, that Parkinson’s disease patients with poor vision have a worse phenotype with higher rates of dementia ( Hamedani et al , 2020 ; Han et al , 2020 ). Together, this evidence suggests the exciting prospect that routine assessment of vision may have a role in disease stratification for cognitive decline in Parkinson’s disease.…”

“…The event-based model would also be of interest applied to dementia with Lewy bodies or established Parkinson’s disease dementia. As visual processing deficits are seen in the prodromal phase of dementia with Lewy bodies ( McKeith et al , 2020 ) and in patients with more rapid Parkinson’s disease dementia ( Anang et al , 2014 ; Hamedani et al , 2020 ), we predict that visual changes will also be found as early events in Lewy body dementia.…”

Visual Dysfunction and Parkinson's Disease

“…Both take advantage of established clinical databases with secure PD diagnoses and accurate measures of visual function captured in their relative populations. 6,7 These studies highlight 2 distinct and clinically relevant aspects of visual dysfunction in PD: (1) that loss of visual function may be found at the very earliest stages of PD, a kind of early nonmotor sign, and (2) that visual dysfunction in established PD is a marker of poor prognostic outcomes.…”

Visual dysfunction predicts cognitive impairment and white matter degeneration in Parkinson’s disease

“…The risk of dementia is markedly increased in Parkinson's disease (PD) but its onset and severity is highly heterogeneous 1,2 , making individual-level predictions difficult and limiting timely therapeutic interventions. There is now a growing body of evidence that Parkinson's patients with visual dysfunction are at a greater risk of dementia [3][4][5] , but whether this translates into structural change over time is not yet known.…”