A comparison of visual problems in the parkinsonian syndromes

Five disorders currently comprise the ‘Parkinsonian syndromes’, viz. Parkinson’s disease (PD), progressive supranuclear palsy (PSP), dementia with Lewy bodies (DLB), multiple system atrophy (MSA), and corticobasal degeneration (CBD). Differential diagnosis of these disorders can be challenging but if ocular signs and symptoms are present they may aid clinical diagnosis. Visual problems in the Parkinsonism syndromes may involve visual acuity (VA), contrast sensitivity (CS), color vision, pupil reactivity, and eye movements; more complex aspects of vision such as reading ability, visuo-spatial orientation, the identification and naming of objects, and visual hallucinations. No single visual feature can definitively diagnose a specific Parkinsonism syndrome. Nevertheless, the presence of visual hallucinations and color vision problems may be more characteristic of DLB and PD than CBD or PSP and vertical supranuclear gaze palsy may be a significant feature of PSP. In addition, variation in saccadic eye movement (SEM) problems may help to distinguish PD and CBD from PSP. A multidisciplinary approach is often necessary to manage the visual problems of patients with a Parkinsonism syndrome.