Ocular neuromyotonia in Graves dysthyroid orbitopathy.

OBJECTIVES

To describe 2 patients with ocular neuromyotonia in association with Graves orbitopathy and to consider the possible underlying mechanisms.

DESIGN

Description of the clinical findings in 2 patients with these conditions.

SETTING

Neuro-ophthalmology referral centers.

PATIENTS: Two patients, aged 55 and 52 years, had episodic, involuntary periods of vertical diplopia and dysthyroid orbitopathy.

INTERVENTION: Treatment with carbamazepine in one patient and external beam radiation therapy in the second patient.

MAIN OUTCOME MEASURES: Frequency and duration of episodic spasms of the extraocular muscles.

RESULTS

Although radiation therapy is the most common association with ocular neuromyotonia, it cannot explain the involuntary contractions of extraocular muscles in all affected patients. Other mechanisms must be involved, such as those discussed in this article.

CONCLUSION

Ocular neuromyotonia is described in 2 patients with dysthyroid orbitopathy, confirming previous findings. Possible mechanisms are given.