Abstract

Functional (psychogenic) eye movements include convergence spasm, functional limitation of gaze, functional (or “voluntary” nystagmus), and functional convergence paralysis. Despite an increasing awareness of the high prevalence of functional neurological disorders, there has been no systematic clinical evaluation of functional eye movement disorders, or appreciation of the scale of the problem. We performed a retrospective review of patient case records attending two specialist neuro-otology outpatient clinics to determine the prevalence and clinical phenotype of functional eye movement disorders. Our results have confirmed that functional eye movements are a common presentation to neuro-otology clinics, with a prevalence of upto 4%. Convergence spasm and functional limitation of gaze are the commonest types seen in our clinics. Almost half the patients with a functional eye movement disorder had an associated functional non-ocular movement disorder, most commonly affecting gait. Early identification of functional eye movements may contribute to a positive diagnosis of a functional movement disorder, and prevent unnecessary – and potentially harmful – invasive investigations and treatments.