Opsoclonus is a rare condition that causes rapid, involuntary eye movements. There are several synonyms used to describe this disorder, including saccadomania, ocular flutter, and dancing eyes syndrome. Saccadomania is a term that describes the uncontrollable jerky movements of the eyes that occur in opsoclonus. Ocular flutter is another name for this condition, which is characterized by rapid back-and-forth eye movements that interfere with vision. Dancing eyes syndrome is a more colloquial term for opsoclonus and refers to the appearance of the eyes as they rapidly dance around. While these synonyms are used interchangeably to refer to opsoclonus, they all describe the same condition with varying degrees of specificity.