To see a typical case presentation with Duane syndrome type I, click here.
(1) Duane syndrome type I is the most common of the retraction syndromes. The differential diagnosis between abducens palsy (see 2.45) and Duane syndrome type I is not difficult in older children and adults. However, in young children and especially infants, a Duane syndrome is easily mistaken for a sixth nerve palsy. The consequences of this error are not negligible because the surgical treatment for abducens palsy (see 2.46) would be contraindicated in Duane syndrome. Because Duane syndrome is often associated with systemic anomalies, affected children should have a complete physical examination.58, p.398
(2) The medial rectus muscle may be tight after previous resection, which limits abduction.
(3) Conjunctival scarring involving the temporal aspect of the globe, as occurs after repeated surgeries for pterygium or after removal of a conjunctival lesion may cause retraction of the globe on attempted adduction.
(4) Retraction of the globe, narrowing of the lid fissure on adduction, and widening on attempted abduction are signs that may be difficult to detect in esotropic infants. Limitation of abduction and crossed fixation are frequently present in essential infantile esotropia, a condition that must be distinguished from Duane syndrome type I.
(5) Although numerous surgical approaches have been advocated to improve abduction in eyes with Duane syndrome type I, success is limited in our opinion. Most attempts to improve abduction by surgery on the involved eye result in increased retraction of the globe on adduction.
(6) An esotropia in primary position causes uncrossed diplopia with a compensatory head turn toward the involved side. A recession of the medial rectus muscle improves the head position but, at the same time, may cause limitation of adduction.24, p.421
(7) It has been shown by modern imaging techniques that there is little if any vertical movement of the muscle planes of the horizontal rectus muscles in relation to the bony orbit as the eye is elevated or depressed.5 Therefore, it must be assumed that the globe slips beneath the muscles during vertical eye movements. Co-contraction of the horizontal rectus muscles, as occurs in Duane syndrome on attempted adduction, changes their action to one of elevation or depression, depending on whether the globe is slightly elevated or depressed.51 When upshoot and downshoot cause cosmetic concern, recession of the horizontal recti62 is effective (see 2.17 and 2.18). The oblique muscles should not be weakened.
