ABSTRACT
Compensatory head posture is a common adaptation to incomitant strabismus due to any cause, including disorders of the rectus extraocular muscle (EOM) pulleys. There are three general classes of pulley pathology: heterotopy, static malpositioning that obliquely misdirects rectus EOM force; instability, gaze-related orbital pulley shift (GROPS) that may misdirect EOM force or restrict duction; and hindrance to normal pulley travel along the EOM axis that restricts duction. Orbital imaging demonstrates these distinct mechanisms of strabismus, each generally requiring different treatment.
