前弹力层下激光角膜磨镶术中负压吸引圆环与椭圆环对角膜散光的影响

Comparison of the astigmatic results of circular vacuum aspiration rings and oval vacuumaspiration rings in sub-Bowman＇s keratomileusis

目的探讨前弹力层下激光角膜磨镶术（SBK）手术中运用负压吸引圆环与椭圆环对患者术后角膜散光的影响。方法回顾性病例对照研究。收集2011年3月在四川大学华西医院近视激光中心行SBK患者51例（102眼），在制作角膜瓣时，分别采用圆环和椭圆环，其中圆环组23例，椭圆环组25例。另外3例左右眼分别使用圆环与椭圆环，圆环眼纳入圆环组，椭圆环眼纳入椭圆环组。Orbscan11角膜地形图检查患者术前、术后水平及垂直方向角膜曲率，并计算患者术前、术后散光值。采用独立样本t检验进行统计分析。结果术后1周，圆环组角膜散光值为（-0．84±0．71）D，椭圆环组角膜散光值为（-0．90±0．54）D，两组之间差异无统计学意义。排除术中矫正散光值的影响，术前与术后1周角膜散光值差值椭圆环组为（0．58±0．77）D，圆环组为（0．57±0．76）D，两组差异无统计学意义。所有病例术中术后均未出现游离瓣、不全瓣、纽扣瓣等角膜瓣并发症，术后角膜愈合过程也未出现层间异物、瓣溶解、感染等严重影响视力的并发症。结论相对传统负压吸引圆环来说，SBK手术中负压吸引椭圆环不会引起角膜散光值增加或降低。

Objective To Compare the astigmatic results between circular vacuum aspiration rings and oval vacuum aspiration rings in Sub-Bowman＇s Keratomileusis （SBK）. Methods It was a retrospective case controlled study. A total of 51 patients （102 eyes） who underwent SBK in the West China Hospital. Either circular vacuum aspiration rings or oval vacuum aspiration rings were chosen to make the corneal flaps. Circular vacuum aspiration rings were used in 49 eyes and oval vacuum aspiration rings were used in the other 53 eyes. Corneal curvature was measured with corneal topography and was used to calculate the astigmatic values. An independent samples t test was used. Results The astigmatic values 1 week after surgery for the oval vacuum aspiration ring group were -0.90±0.54 D and -0.84±0.71 D for the circular vacuum aspiration ring group. Astigmatic values change before 1 week after surgery in the oval vacuum aspiration ring group was 0.58±0.77 D and was 0.57±0.76 D in the circular vacuum aspiration ring group. There was no significant difference between the two groups. No complications were detected that would significantly affect visual acuity during or after surgery. Conclusion These results suggest that oval vacuum aspiration rings in SBK will not increase the induced astigmatism.