目的：描述伴有面转代偿头位的先天性单纯下直肌麻痹患者的临床表现，并分析其手术治疗效果。

方法：回顾性分析2014-05/2018-07伴有明显面转代偿头位的先天性下直肌麻痹患者，手术前后患者面转程度的变化借助骨科量角器来检查，垂直、水平斜视度变化通过三棱镜交替遮盖试验来测量，旋转斜视度变化通过眼底对眼球客观旋转状态评估。下直肌缩短术是主要治疗方案。

结果：在15例研究对象中，有13例行下直肌缩短术或者联合上直肌后徙术术后疗效好，下直肌运动不足明显改善，眼球运动协调，以面转为主的代偿头位消失，垂直、水平、旋转斜视得到矫正； 并得出：每缩短1 mm下直肌可矫正1.54±0.93°内旋斜视。而行下斜肌断腱术治疗的垂直斜视度小的患者，面转改善不理想，仍遗留眼球运动不协调。

结论：先天性单纯的下直肌麻痹以面转代偿头位为主，下直肌缩短术治疗效果好，轻度的过矫及欠矫不影响手术疗效。

METHODS: Fifteen patients with IR muscle palsy further presenting with abnormal compensatory head posture of facial rotation were retrospectively identified from May 2014 to July 2018. Changes in the degree of facial rotation in patients were evaluated using an orthopedic goniasmometer. Variations in vertical and horizontal deviations were measured through prism and alternate cover tests, and changes in cyclotropia of pre- and postoperation were assessed by objective evaluation of eye torsion with fundus photography. IR resection was the main surgical treatment.

RESULTS: Among the 15 patients, 13 who were subjected to IR muscle resection or IR muscle resection combined with superior rectus muscle recession showed good results after surgery. These results included improved underaction of IR, coordination of eye movement, disappearance of abnormal facial rotation of compensatory head position, and total correction of vertical and horizontal deviation and cyclodeviation. Furthermore, each 1 mm resection of IR can correct 1.54±0.93° incyclotropia. In the other two patients with small vertical deviation who were done by inferior oblique myectomy, the improvement in facial rotation was unsatisfied, and eye motion remained uncoordinated.

CONCLUSION: Congenital isolated IR muscle palsy characterized by compensatory head posture of facial rotation is the main compensatory head posture. The resection of IR is effective and perfect. Mild overcorrection and undercorrection do not influence curative effect.