A 5-year-old girl is referred by her pediatrician for evaluation of esotropia. Ophthalmologic examination reveals esotropia in the primary position with markedly limited abduction of the left eye, although there is minimal restriction of adduction of the left eye and lid fissure narrowing on attempted adduction. Right ocular motility and fissure height are normal. This case most likely represents which one of the following syndromes?
|A.||Duane’s retraction syndrome (DRS) type I|
DRS type II
DRS type III
Answer: A. Duane’s retraction syndrome (DRS) type I
Explanation: DRS occurs in approximately 1% of all patients with strabismus. Its clinical features include a unilateral or bilateral abnormality of horizontal gaze, retraction of the globe on attempted adduction, and upshooting or down shooting of the globe on adduction. The left eye is affected more frequently than the right, and females are affected more frequently than males. DRS may be divided into three types. DRS type I is characterized by marked limitation of abduction with normal or minimal restriction of adduction. Electromyography reveals an absence of electrical activity in the lateral rectus muscle on abduction with paradoxical activity on adduction. DRS type II is characterized by marked limitation of adduction with normal or minimal restriction of abduction. Electromyography reveals electrical activity of the lateral rectus muscle both on adduction and abduction. DRS type III is characterized by marked restriction of abduction as well as adduction. Electromyography reveals electrical activity of both the lateral and medial rectus muscles on both adduction and abduction. Type I is the most common form of DRS, and type III is the least common. Although the majority of patients with DRS type I and type II will have straight eyes, some type I patients develop an esodeviation in primary position and some type II patients develop an exodeviation. Amblyopia may be present in 10% to 14% of patients with DRS. Several ocular and systemic anomalies have been associated with DRS: cataracts, iris anomalies, Marcus Gunn jaw winking, microphthalmos, crocodile tears, Goldenhar syndrome, maternal thalidomide use, and Klippel–Feil syndrome. Brown syndrome is characterized by the inability to actively or passively elevate the eye in the adducted position. It may be acquired or congenital. There is normal or nearly normal elevation of the eye in abduction.