Résumé
A four-year-old child with a clinical diagnosis of unilateral congenital fibrosis of extraocular muscles (CFEOM) was planned for inferior and medial rectus muscle recession surgery, adjusted with the status of forced duction test. Due to pathological changes within the muscles subsequent to innervational abnormality, intraoperatively the inferior rectus muscle was pulled into two following the insertion of muscle hook. Moreover, the snapped muscle fibers could not be identified, thus further surgery was abandoned and an observation was commenced. At the end of 6 weeks, there was a significant reduction in the amount of hypotropia but clinically significant perverted convergence with esotropia necessitated further surgical intervention. A second surgical intervention consisting of medial rectus transposition to superior rectus with 3 mm recession was performed to achieve acceptable results in the primary gaze.