Duane retraction syndrome 2
Overview
Limitation of adduction (corresponds to Brown's Type C)which Hubel explains as being caused by co-innervation of both medial and lateral recti on attempted adduction, and
Symptoms
1. Limitation of abduction (outward movement) of the affected eye. 2. Less marked limitation of adduction (inward movement) of the same eye. 3. Retraction of the eyeball into the socket on adduction, with associated narrowing of the palpebral fissure (eye opening) 4. Widening of the palpebral fissure on attempted abduction. (N.B. Mein and Trimble [3] point out that this is "probably of no significance" as the phenomenon also occurs in other conditions in which abduction is limited). 5. Poor convergence 6. A face turn to the side of the affected eye to compensate for the movement limitations of the eye(s) and to maintain binocular vision.
Causes
The mechanical factors noted by Miller and Clark above are generally regarded as arising secondary to loss of innervation. During corrective surgery fibrous attachments have been found connecting the horizontal recti and the orbital walls and fibrosis of the lateral rectus has been confirmed by biopsy. This fibrosis can result in the lateral rectus being 'tight' and acting as a tether or leash. Co-contraction of the medial and lateral recti allows the globe to slip up or down under the tight lateral rectus producing the up and down shoots characteristic of the condition.