Cyclic esotropia after a traumatic sixth nerve palsy in a child.

Cyclic esotropia is a rare phenomenon in which esotropia and orthophoria alternate over a period of 48 to 96 hours. The mechanism that underlies the phenomenon is unknown. Cyclic esotropia often occurs after a fusion-disrupting event. We report an unusual case of cycling esotropia with onset after a traumatic sixth nerve palsy. The cyclic phase persisted for 2 years, following a 48-hour alternate-day pattern. After strabismus surgery for the esotropic angle, the deviation disappeared and the patient remained orthotropic, with 1 year of follow-up to date.