Ocular flutter associated with a localized lesion in the paramedian pontine reticular formation

Ocular flutter is a rare horizontal eye movement disorder characterized by rapid saccadic oscillations. It has been hypothesized that it is caused by loss of "pause" neuronal inhibition of "burst" neuron function in the param edian pontine reticular formation (PPRF); however, there have been no imagi ng studies confirming such anatomical localization. We report the case of a woman with an acute attack of multiple sclerosis associated both with ocul ar flutter and a circumscribed pontine lesion, mainly involving the PPRF on magnetic resonance imaging. As she recovered from the attack, both the mid line pontine lesion and the ocular flutter dramatically improved. This case is the first clear evidence that at least some cases of ocular flutter are due to lesions involving the PPRF.