Factors predicting upshoots and downshoots in Duane's retraction syndrome

Purpose: Factors predicting mechanical and innervational types of upshoots; and downshoots in Duane's retraction syndrome were evaluated. Methods: This retrospective study evaluated upshoots and downshoots in 196 patients (222 eyes) with Duane's retraction syndrome seen between January 1990 and July 2001. On the basis of the clinical characteristics, upshoots and downshoots were classified as mechanical type, innervational type, or both. Factors potentially predicting the upshoot-downshoot phenomenon that were studied included patient age, type of Duane's retraction syndrome, horizontal strabismus, and vertical tropia in the primary position of gaze. Results: Upshoots; and downshoots were present in 39% of the eyes. The mechanical type was more common than the innervational type (26% vs 12%). Overall, upshoots and downshoots; were statistically significantly more common in type III Duane's retraction syndrome, with exotropia, and with vertical tropia in primary position. Patient age had no correlation with upshoots; or downshoots. Both types of upshoots and downshoots were significantly more common in type III Duane's retraction syndrome. A statistically significant association was found between exotropia and the mechanical type, and between vertical tropia in primary position and the innervational type. Conclusions: All patients with type III Duane's retraction syndrome, exotropia, and vertical tropia in the primary position of gaze should be examined for upshoots-and downshoots. One should look specifically for the mechanical type when there is exotropia and for the innervational type when there is a large vertical tropia in the primary position of gaze.