Ophthalmological findings in movement disorders

Ocular manifestations form an important clinical component of several movement disorders. Both hypokinetic and hyperkinetic movement disorders can involve the eye. Ophthalmological manifestations can arise due to dysfunction at the level of retina, optic nerves, oculomotor system, or subcortical or visual cortex. Ophthalmological findings help in differentiating various movement disorders and give a clue about their severity. These follow or may precede the diagnosis of movement disorders. Basal ganglia and its various nuclei especially substantia nigra pars reticulata play an important role in the genesis of eye movements through its connections with the superior colliculus. Eye movement abnormalities using quantitative recording techniques are now being considered as noninvasive biomarkers not only for the diagnosis but also to track the progression of disease as well as to study the effects of therapies in various movement disorders. Moreover, there is ample evidence of presence of retinal degeneration in various neurodegenerative diseases evaluated using optical coherence tomography. Various patterns of retinal thinning have been described in different movement disorders and have been found to have a correlation with the stage and severity of the disorder. In this review, we discuss ophthalmological findings of common hypokinetic and hyperkinetic movement disorders.