A cyclic vertical deviation with dysthyroid ophthalmopathy: a case report

Cyclic strabismus is a very rare condition of ocular motility characterized by alternating strabismus and orthotropia. We report a patient with a 48-h cycle of vertical deviation associated with dysthyroid ophthalmopathy that spontaneously resolved.

A 40-year-old woman experienced sudden onset vertical double vision. She had already been diagnosed with hyperthyroidism. Asymmetric enlargement of the inferior and medial rectus muscles was demonstrated in her left eye on computed tomography, and was compatible with dysthyroid ophthalmopathy. She clearly described the "every-other-day" pattern of diplopia that spontaneously switched around 8 o'clock every night. She exhibited left hypotropia of 35 prism diopters on a bad day, and 7 prism diopters on a good day.

This case illustrates that cyclic vertical deviation may spontaneously resolve along with the course of the underlying diseases that initiated the cyclic deviation, especially in patients with conditions involving motor component changes such as dysthyroid ophthalmopathy.