Schliesser, Joshua A.Sprunger, Derek T.Helveston, Eugene M.2017-06-212017-06-212016-08Schliesser, J. A., Sprunger, D. T., & Helveston, E. M. (2016). Type 4 Duane syndrome. Journal of American Association for Pediatric Ophthalmology and Strabismus, 20(4), 301–304. https://doi.org/10.1016/j.jaapos.2016.05.012https://hdl.handle.net/1805/13142Purpose To identify cases of synergistic divergence whose characteristics suggest that this entity is a form of Duane syndrome. Methods The records of all patients with a Duane syndrome diagnosis, including standardized eye position photographs, from the E-Consultation program of Cybersight, Orbis International were analyzed. Results A total of 350 Duane syndrome cases were identified. Of these, 19 (5%) had features consistent with synergistic divergence, or type 4 Duane syndrome. Of the 19, 16 (84%) were male, 15 (79%) had palpebral fissure narrowing, all had anomalous head posture, and 18 (95%) were exotropic. Only 9 (47%) patients were reported to have undergone surgery. Conclusions Synergistic divergence is a rare entity with features similar to those of Duane syndrome. We suggest that this entity be classified as type 4 Duane syndrome, because it has unique findings and an innervation pattern that differs from the other 3 recognized types.enPublisher PolicyDuane Syndromesynergistic divergenceArticle