Background: There are various surgical procedures for the treatment of congenital (“ true” ) Brown s syndrome. We have evaluated the effects of a superior oblique tendon recession. Patients and Methods: In a retrospective study, we evaluated the files of 22 patients who received surgery for congenital Brown s syndrome in our department. A recession of the superior oblique tendon was performed,when there was a hypotropia in primary position with an abnormal head posture and a significant elevation deficit in adduction, and when these findings did not improve spontaneously. The squint angles (alternate prism and cover test), the monocular motility and the abnormal head posture at distance fixation were assessed. The measurements were performed 1 day before and 3 months after surgery. Thirteen patients were examined 2-10 years after surgery. Results: At the time of surgery, the patients were 4-17 years old (median 7 years), 13 were male, in 15 patients, the right eye was concerned. Eight patients had an additional esotropia, one patient was exotropic. The vertical deviation in straight gaze was 0-12 deg (median 7 deg). The elevation of the eye was restricted to-10 deg (belowhorizontal) to 15 deg (median 0 deg) in adduction and to 10-35 deg (median 25 deg) in abduction. Sixteen patients had an abnormal head posture. The superior oblique tendonwas recessed by 10 mm, in some patients with an additional loop (6x0 polyester). Nine patients received simultaneous surgery for their eso/exotropia. At the end of the operation, the elevation of the eye in adduction (forced duction test) was free. Three months postoperatively, the vertical deviation was 0-6 deg (median 1 deg). Twelve patients did not show any abnormal head posture. Inspite of free passive motility, the monocular elevation in adduction was only slightly improved to-5 to 15 deg (median 5 deg). At the late control, the hypotropia (0-4 deg, median 0 deg) and the elevation in adduction (5-35 deg, median 15 deg) were significantly improved. Conclusion: The recession of the superior oblique tendon is an effective and safe surgical procedure for congenital Brown s syndrome. The efficiency of the procedure is individually variable. Presumably, this variability was caused by the heterogenous etiology of Brown s syndrome rather than by surgical technique. The hypotropia and the abnormal head posture were reduced immediately after surgery, while the delayed improvement of active elevation in adduction often remained incomplete. Postoperative forced upgaze trainingmay be beneficial. u001a Background: There are various surgical procedures for the treatment of congenital (“true”) Brown’s syndrome. We have evaluated the effects of a superior oblique tendon recession. Patients and Methods: In a retrospective study, we evaluated the files of 22 patients who received surgery for congenital Brown’s syndrome in our department. A recession of the superior oblique tendon was performed, when there was a hypotropia in primary position with an abnormal head posture and a significant elevation deficit in adduction, and when these findings did not the spontaneously. The squint angles (alternate prism and cover test), the monocular motility and the abnormal head posture at distance fixation were assessed. The measurements were performed 1 day before and 3 months after surgery. Thirteen patients were examined 2-10 years after surgery. Results: At the time of surgery, the patients were 4-17 years old (median 7 years), 13 were male, in 15 patients, the right eye was concern ed. Eight patients had an additional esotropia, one patient was exotropic. The vertical deviation in straight gaze was 0-12 deg (median 7 deg). The elevation of the eye was restricted to-10 deg (below horizons) to 15 deg 0 deg) in adduction and to 10-35 deg (median 25 deg) in abduction. Sixteen patients had an abnormal head posture. The superior oblique tendonwas recessed by 10 mm, in some patients with an additional loop (6x0 polyester). Nine patients received simultaneous surgery for their eso / exotropia. At the end of the operation, the elevation of the eye in adduction (forced duction test) was free. Three months postoperatively, the vertical deviation was 0-6 deg (median 1 deg). Twelve Inspite of free passive motility, the monocular elevation in adduction was only slightly improved to-5 to 15 deg (median 5 deg). At the late control, the hypotropia (0-4 deg, median 0 deg) and the elevation in adduction (5-35 deg, median 15 de g) weresignificantly improved. Conclusion: The recession of the superior oblique tendon is an effective and safe surgical procedure for congenital Brown’s syndrome. The efficiency of the procedure is individually variable. Presumably, this variability was caused by the heterogenous etiology of Brown’s syndrome rather than by surgical technique. The hypotropia and the abnormal head posture were reduced immediately after surgery, while the delayed improvement of active elevation in adduction often was incomplete incomplete. Postoperative forced upgaze trainingmay be beneficial. u001a