The eyes and Parkinsonian syndromes

Parkinsonian degenerative syndromes, including Parkinson disease (PD), progressive supranuclear palsy (PSP), multiple system atrophy (MSA), corticobasal degeneration (CBD), and dementia with Lewy bodies (DLB), are frequently associated with ophthalmic manifestations that contribute substantially to impaired quality of life, reduced functional independence, and increased falls risk. These visual disturbances remain under-recognised in routine neurological practice despite their diagnostic and therapeutic relevance. This review summarises the spectrum of ophthalmic manifestations across Parkinsonian degenerative syndromes, focusing on ocular motor dysfunction, eyelid and ocular surface disorders, higher-order visual perceptual dysfunction, and treatment-related visual phenomena. Characteristic patterns of eye movement abnormalities, visual hallucinations, visuospatial dysfunction, dry eye disease, and eyelid dysfunction may assist clinical differentiation between syndromes and identify treatable causes of visual impairment. Practical management strategies including ophthalmological assessment, orthoptic interventions, optimisation of refractive correction, and ocular surface treatment are discussed. Emerging technologies including retinal imaging, oculomics, quantitative eye movement analysis, and tear biomarkers may further enhance future diagnosis and disease monitoring, although their clinical utility remains under investigation.