Visual complaints and disorders in patients with Parkinson's disease

Visual disorders of patients with Parkinson's disease (PD) are often not well documented. Consequently, these disorders may be underestimated and patients might not receive appropriate care, resulting in a decline of quality of life. Therefore, we aim to explore the prevalence, nature and severity of visual complaints and visuo-perceptual disorders in patients with PD. We developed a 19-item questionnaire to screen for visual complaints (Huizinga et al., 2020), which was used as a referral tool for further care. In total, 350 patients and 1054 healthy controls completed the questionnaire. Based on reported visual complaints, 35 patients were referred for visual rehabilitation. These patients were administered the DiaNAH test battery for visual perception (De Vries et al., 2018). Around 90% of patients reported to have one or more visual complaints. The most common complaints were blurry vision, having difficulty focusing and having difficulty reading, which were experienced by more than half of the patients. Altered color perception and experiencing visual field loss were least common, but nevertheless experienced by around 10% of patients. All complaints were more common or more severe in patients compared to healthy controls. DiaNAH test scores suggest that the most frequently occurring disorder was limited visuomotor speed and visual search in a complex task, found in over half of the patients. Diminished figure-ground perception, visuocognitive load, and visuospatial functioning were also found in almost half of the patients. Compared to normative data of healthy individuals, patients attained an abnormal score on an average of 3 out of 11 tests. Visual complaints are very common among patients with PD. Furthermore, a range of visual perceptual disorders commonly occur in patients with PD referred for visual care and rehabilitation. Recognition and knowledge of these visual complaints and disorders are important in order to improve quality of care and rehabilitation.