Traumatic Exotropia Following Partial Laceration of Medial Rectus Muscle

ABSTRACT

Direct trauma to extraocular muscles is usually the result of penetrating injuries. Contusion, avulsion, or laceration of the extraocular muscles may occur. We have treated a 3-year-old boy with what appeared to be nasal conjunctival laceration by scissors. The injured eye showed approximately 50 prism diopter exotropia and slight limitation of adduction of the left eye. In orbital MRI focal hemorrhage and adhesion around left medial rectus muscle was noted but the discontinuity of left medial rectus muscle was not found in orbital MRI. After 6 months, the child underwent strabismus surgery under general anesthesia. We detected that the upper portion of the left medial rectus muscle was lacerated about 25% of total width of muscle from the insertion to 4mm distal to the insertion. We performed a recession-resection procedure to the left eye. 3 month after the operation, duction movement showed no limitation. The prism and cover test at near revealed orthophoria. We suggest that a strabismus following after a periocular laceration can be accompanied with a injury of extraocular muscle.