方法：回顾性分析2019-09/2021-08在我院行IOBT术的患者，纳入标准为单眼下斜肌轻度亢进(2+及以下)，并伴有轻度非共同性垂直斜视(4～9PD)。水平斜视按照常规手术量和方式设计，同期单侧下斜肌亢进眼行单眼IOBT术。观察手术前后水平斜视度、垂直斜视度、侧方注视位垂直斜视度、黄斑视盘夹角及下斜肌亢进程度等。

结果：纳入病例共16例16眼，年龄4～39岁。1例为先天性内斜视术后5a，单眼上斜肌轻度麻痹继发下斜肌功能亢进，余15例均为原发性下斜肌功能亢进伴水平斜视。随访时间为3～6mo。术前和术后平均下斜肌亢进程度分级分别为+2.00(2.00，2.00)级和0.00(0.00，0.00)级(Z=-3.704，P<0.001)，平均改善2.00(1.25，2.00)级； 水平斜视度从术前69.13±25.86PD减少到术后2.75±2.59PD(t=9.929，P<0.001)； 第一眼位垂直斜视从术前7.44±1.32PD减少到术后1.00±1.21PD(t=22.335，P<0.001)，平均矫正上斜视为6.44±1.15PD； 侧方注视垂直斜视从术前12.44±2.73PD减少到术后3.00±2.13PD，平均矫正9.44±2.73PD(t=13.819，P<0.001)。黄斑中心凹-视盘中心夹角度数(FDA)术前为-8.85°±6.53°，术后为-6.49°±7.01°(t=-2.384，P<0.001)，平均减少2.36°。未见术后过矫及下斜肌功能不足等并发症。

结论：IOBT术对矫正单侧轻度下斜肌亢进伴小度数垂直斜视是安全有效的。

METHODS: The data of patients who underwent IOBT in our hospital from September 2019 to August 2021 were analyzed retrospectively. Inclusion criteria targeted patients with mild inferior oblique overaction(2+ and below)and small angle incomitant vertical strabismus(4-9PD). The horizontal deviation and vertical deviation in both primary and lateral gazes were measured, and the degree of inferior oblique overaction and fovea-disc angle(FDA)were also evaluated preoperatively and postoperatively.

RESULTS: A total of 16 cases(16 eyes)were included, aged 4-39 years. One case was 5a postoperative congenital esotropia with secondary unilateral inferior oblique overaction by mild superior oblique palsy, whereas 15 patients had monocular primary inferior oblique overaction with horizontal strabismus. The follow-up was 3-6mo. The mean improvement of inferior oblique overaction was 2.00(1.25, 2.00)grade from +2.00(2.00, 2.00)preoperatively to 0.00(0.00, 0.00)postoperatively, the difference was statistically significant(Z=-3.70, P<0.001). The horizontal strabismus decreased from 69.13±25.86PD preoperatively to 2.75±2.59PD postoperatively(t= 9.929, P<0.001). The vertical strabismus in the primary position decreased from preoperative 7.44±1.32PD to 1.00±1.21PD postoperatively(t=22.335, P<0.001), mean corrected hypertropia 6.44±1.15PD, and vertical strabismus in lateral gazes decreased from preoperative 12.44±2.73PD to 3.00±2.13PD postoperatively, mean corrected hypertropia 9.44±2.73PD, these differences were statistically significant(t=13.819, P<0.001). The FDA decreased from -8.85°±6.53° preoperatively to -6.49°±7.01° postoperatively, the difference was statistically significant(t=-2.384, P<0.001), with a mean reduction of 2.36°. No postoperative complications such as postoperative overcorrection or inferior oblique underaction were observed.

CONCLUSION:IOBT is safe and effective in correcting unilateral mild inferior oblique overaction with small angle vertical strabismus.