Ocular neuromyotonia after peribulbar block

A man in his 60s developed an intermittent, variable left hypotropia with symptomatic diplopia following nasal pterygium surgery in the left eye. No tropia was present for most of the day, but a variable left hypotropia of 25^Δ could be provoked with downgaze. There was no history of radiation or other trauma. Magnetic resonance imaging of the brain and orbits with gadolinium was unremarkable. The patient was diagnosed with suspected ocular neuromyotonia secondary to the peribulbar block and temporarily managed with Fresnel prism. A trial of oral carbamazepine partially improved symptoms. He ultimately underwent a left inferior rectus recession with near complete resolution of his symptoms.