Oscillopsia: causes and management.

PURPOSE OF REVIEW Oscillopsia is an illusion of an unstable visual world. It is associated with poor visual acuity and is a disabling and distressing condition reported by numerous patients with neurological disorders. The goal of this study is to review the recent findings in the various pathophysiological mechanisms of oscillopsia and the potential treatments available. RECENT FINDINGS Oscillopsia most often results from abnormal eye movements or from impaired vestibulo-ocular reflex. A special emphasis is provided on new hypotheses concerning the mechanisms of pendular nystagmus associated with oculopalatal tremor; on the clinical relevance of fixation instability in the diagnosis of degenerative disease; and on the causes of vestibular areflexia. Oscillopsia could also theoretically result from a deficit in mechanisms underpinning perceptual stability maintenance despite constant gaze displacement in the environment. The recent findings concerning the mechanisms and underlying neural network subserving this phenomenon of 'spatial constancy' are developed. SUMMARY Oscillopsia may result either from impaired ocular stability or impaired compensation or suppression of afferent visual information resulting from normal eye movements. Understanding the exact mechanisms of oscillopsia may lead to novel treatment.