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Ocular neuromyotonia (ONM) is a rare disorder of ocular mal-alignment in which painless, transient spontaneous or gaze-induced abnormal deviation of the eye manifests as episodic diplopia. With only a few cases reported in the literature, ONM mostly follows months to years after cranial irradiation for sellar or suprasellar lesions. Here we present two patients with this rare ocular condition, secondary to brainstem demyelination, the association of which is hitherto unreported in the literature. Both patients were 15-year-old girls who presented to us with episodic forced-eye deviation with diplopia. Examination during these attacks revealed ONM involving the superior rectus and medial rectus in the first and second patient, respectively. There was clinical evidence of intrinsic brainstem involvement with downbeat nystagmus and skew deviation in one patient without any other cerebellar or long tract signs. MRI showed evidence of demyelination involving the brainstem in both, with CSF showing positive immunological markers and with positive aquaporin-4 antibody in one patient. Both patients responded remarkably to immunomodulatory therapy and are asymptomatic at follow-up. That ONM can occur with brainstem demyelination has not been reported in the literature. This association may help in explaining the pathophysiology of ONM as secondary to segmental demyelination., (© The Author(s) 2014.)

Ocular neuromyotonia is an episodic involuntary contraction of one or more of the extraocular muscles resulting from spontaneous neural discharges of the oculomotor nerve. It is characterized by symptomatic diplopia for the duration of the contraction and occurs either spontaneously or after a sustained eccentric gaze. Although the mechanism of ocular neuromyotonia is not fully understood, primary or secondary aberrant regeneration and consequent ephaptic transmission generally are held to be involved. We report the case of a patient with right oculomotor neuromyotonia accompanied by lid ptosis on abduction of the left eye who was successfully treated with oral carbamazepine., (Copyright © 2013 American Association for Pediatric Ophthalmology and Strabismus. Published by Mosby, Inc. All rights reserved.)

A 27-year-old woman noticed diplopia when gazing left and paresthesia of the left face and headache of the left side for 8 months. Abduction and supraduction of the left eye were moderately restricted. Hypoesthesia of the face innervated by the ophthalmic branch of the left trigeminal nerve was detected. Visual disturbance due to optic neuropathy developed 5 months later. MRI with gadolinium revealed a mass lesion extending from the left cavernous sinus to the orbital apex. Ocular neuromyotonia and corresponding diplopia were induced by sustained right gaze. Such episodes occurred almost every day on awaking in the morning. Prednisolone (60 mg/day) was given and the headache and visual disturbance ameliorated in two days. The diplopia disappeared in 4 days. The patient remains free from these symptoms after 6 months. This is the first report of ocular neuromyotonia associated with Tolosa-Hunt syndrome.

Case Report: We describe a 58-year-old man, without history of radiation therapy, who presented with transient episodic diplopia following sustained lateral gaze lasting around 30-50 seconds. He developed a large angle exotropia of the left eye that gradually returned to normal after 50 seconds. Between episodes he was asymptomatic. Partial resolution of his symptoms was obtained after treatment with carbamazepine., Discussion: Neuromyotonia must be considered when evaluating a patient with intermittent diplopia.