Correction of exotropia and improved adduction by fixation of the anterior encircling fascia to the medial rectus insertion site following myectomy of the four horizontal rectus muscles for infantile nystagmus.

Myectomy of the four horizontal rectus muscles for infantile nystagmus syndrome without a null point may improve visual acuity and quality of life. Exotropia and adduction loss are complications of this procedure, although abduction is typically preserved. We investigated whether adduction loss may be rescued by reestablishing the attachment of the anterior intermuscular septum (AIMS) to the globe at the medial rectus insertion. We present 2 cases of exotropia and adduction loss following myectomy and transposition surgery, where the nasal AIMS and the medial rectus insertion site were joined with nonabsorbable polyester suture. Both patients experienced improvements in eye alignment and adduction. Based on radiologic observations of the posterior displacement of the pulley, or posterior intermuscular septum (PIMS), with medial rectus contraction, we hypothesize that adduction and alignment were improved by providing an anterior site of action for the posterior movement of the PIMS.