 Only one prospective randomized clinical trial addresses success rates of BLRrec versus RR for IXT. After between 12-15 months of follow up, 82 of 17 patients undergoing an RR had a satisfactory outcome compared to 52 of 19 patients undergoing a BLRrec. Nevertheless, there are some important limitations of this previous study. The sample size was very small. The study population was a sub-group of patients with basic type IXT, excluding patients with basic IXT whose angle of deviation increased at far distance or following occlusion, thus limiting the generalizability of the results. In addition, outcomes were assessed unmasked, potentially biasing the results. One observational study of 103 patients 90 of whom had basic type IXT found 1-year success rates of 56 for BLRrec and 60 for RR. A retrospective study of 115 patients with basic type IXT reported success rates of 69 for BLRrec and 77 for RR after an average of 15 months of follow up. Other studies comparing surgery types are limited not only by retrospective study design but also by inclusion of other types of exotropia, making it difficult to interpret results. In addition, many different criteria for success are used, precluding meaningful comparison of success rates between studies. This lack of evidence makes it very difficult to counsel parents of children with IXT regarding the likely success and complication rate of either procedure, limiting our ability to make informed management decisions. Establishing the respective failure rates through the proposed study will allow physicians to offer patients the type of surgery with the highest chance of long-term success, minimizing suboptimal results and repeat surgeries. 