제I형 정위 듀안안구후퇴증후군에서 전환된 외사시 듀안안구후퇴증후군

Duane Retraction Syndrome TypeⅠ Converted to Exotropic Duane Retraction Syndrome

Purpose: The aim of this study is to report a case with initially orthotropic and asymptomatic duane retraction syndrome (DRS) type 1, which was converted to exotropic DRS. Case summary: An 4-year-old girl showed limitation of abduction on her left eye and mild upshot, eyeball retraction, and narrowing of palpebral fissure in adduction on left eye, and left orthotropic DRS type1 was diagnosed. No abnormal head posture was seen. 5 years later, she showed exotropia of 14 prism diopter and right head-turn of 20˚. Limitation of abduction was not changed and decreased upshot in adduction was observed. The left lateral rectus muscle was recessed 6 mm for correction of exotropia. After 5 years postoperatively, she had achieved orthotropia in primary gaze with no abnormal head posture. Abduction limitation on the left eye was maintained, similar to the preoperative degree. Conclusions: DRS is a congenital disorder characterized by anomalous nerve innervations and eye movement abnormality. In general, exotropic DRS is expressed by a branch of the oculomotor nerve, strongly innervating the lateral rectus muscle. However, as in this present case, exotropic DRS may appear acquiredly by the secondary change of the lateral rectus muscle.