IRCT20220220054077N1 IRCT 2022-05-28 Mashhad University of Medical Sciences Surgical result of horizontal rectus muscle elongation on large-angle strabismus Evaluation of surgical result of horizontal rectus muscle elongation on large-angle strabismus in patients older than 4 years 2022-06-05 anticipated 13 Complete https://irct.ir/trial/63243 interventional Randomization: N/A, Blinding: Not blinded, Placebo: Not used, Assignment: Single, Purpose: Treatment. N/A Condition 1: large-angle exotropia. Condition 2: large-angle esotropia. Intervention group: The width of the muscle is divided into 3 equal parts, one upper and lower third after sewing with 6-0 vicryl thread is cut from the insertion site and the middle part is cut to the end, which determines the amount of engagement according to the preoperative prediction. It is desired to be sewn. This procedure is performed bilaterally or with antagonist muscle resection on the same side. The choice of one-sided or two-sided operation will be based on the usual criteria. Alternate deviations or cases where the exotropia in far or the esotropia in near are more, preferably with bilateral surgery, and in cases of constant unilateral deviation, surgery will be performed on one eye.. Undecided - It is not yet known if there will be a plan to make this available Justification or reason for indecision in sharing IPD is There is no more information.