[Surgical outcomes of the inverted Brown pattern in children]

Objective: To investigate the clinical characteristics of the inverted Brown pattern in children and the surgical efficacy of inferior oblique weakening for the disease. Methods: It was a retrospective case series study. The medical records of 11 patients (11 eyes) who were diagnosed with congenital superior oblique palsy with the inverted Brown pattern and underwent strabismus surgery in Tianjin Eye Hospital were reviewed. Their pre-and post-operative motility patterns, vertical deviation angle and fundus torsion, intraoperative forced duction test findings of oblique muscles were analyzed. Statistical analyses were conducted using the t-test, ANOVA, and Tukey's test. Results: There were 9 male and 2 female patients, with an average age of 5.5 (3.0, 7.0) years. Four patients previously received oblique muscle surgery for congenital superior oblique palsy. Weakening of the inferior oblique muscle was performed in all patients. The follow-up period was 6 to 8 months. The pre-and post-operative vertical deviation angles in primary gaze were significantly different at 33 cm (11.2^Δ±2.8^Δ vs. 1.1^Δ±1.3^Δ; t=13.6, P<0.05) and at 5 m (11.1^Δ±2.9^Δ vs. 0.7^Δ±1.0^Δ; t=12.1, P<0.05). The mean hyperdeviation in down-and-in gaze of the higher eye was 18.1±6.0 preoperatively and 0.8^Δ±1.5^Δ postoperatively, showing significant difference (t=8.2, P<0.05). The vertical misalignment of the higher eye in up-and-in gaze was 5.3°±4.5° before surgery and 0.3°±0.9° after surgery, with significant difference (t=3.3, P<0.05). There was also a significant difference between the pre-and post-operative fundus torsion angles (ex20.2°±3.5° vs. ex12.8°±4.6°; t=3.2, P<0.05). The torsional forced duction test of inferior oblique measurements yielded internal rotation angles of 14.5°±5.2° and 35.9°±4.4° intraoperatively for the higher eye and the contralateral eye, and 58.6°±7.1° postoperatively for the higher eye, with significant difference (F=165.7, P<0.001). Conclusions: The deficiency of depression in adduction observed in the inverted Brown pattern is caused by inferior oblique muscle tightness. Weakening of the inferior oblique muscle can effectively correct the misalignment in primary gaze and downward gaze.