Botulinum toxin injection in the patients with Duane syndrome type 1

Purpose to evaluate the efficacy of botulinum toxin injection in the patients with type 1 duane syndrome and identify the predictive factors for success. methods sixteen patients with esotropic type 1 duane syndrome without history of ocular surgery were selected for this interventional case series. the botulinum toxin was injected in the medial rectus of all patients. visual acuity,dry refraction,cyclo-refraction,ocular motility,and amount of deviation were measured. complete success,partial success,and failure were defined as residual deviation/face turn less than 8 prism diopters (pd)/5°,8-20 pd/5-15°,and equal or greater than 20 pd/15°,respectively. results sixteen cases (6 males) were included in our study. the mean esotropia was 26.27 ± 8.35 (12-40 pd) which was reduced significantly to 13.5 ± 12.39 pd during 6 months follow-up (p < 0.001). face turn was improved significantly from a preoperative mean of 18.27° to: 0.094° at 1 week,0.11° at 1 month,3.31° at 3 months,and 7° at 6 months (p < 0.001). complete success was seen in 6 patients (37.5%),partial success in 4 patients (25%),and failure in 6 patients (37.5%). there was a significant relation between the amount of forced duction testing (fdt) and the success rate (p: 0.019). no complication was seen during injections. conclusions botulinum toxin could be an alternative treatment in duane syndrome with appropriate case selection. fdt could be a predictive factor for response to botulinum toxin. © 2016 iranian society of ophthalmology