方法：在角膜最大曲率子午线上做3.0mm切口行白内障超声乳化手术，对术前散光度数≤1.0D的144例156眼术前、术后3mo的资料进行回顾性分析，统计手术前后角膜地形图散光的变化。采用t检验、单因素方差分析、Pearson相关分析对数据进行统计学处理。

结果：3.0mm角膜透明手术切口的术源性散光为0.77±0.53D。患者手术前后的散光对比有统计学意义(P<0.05)，散光变化具有相关性(r=-0.69，P<0.01)。术前角膜散光≤0.25D者术后散光增大，其余组术后散光变小。

结论：利用角膜地形图定位手术切口位置，可以改变超声乳化术后的角膜散光。对于散光范围在0.37～1.0D的患者更适合3.0mm的透明角膜切口。

METHODS:Phacoemulsification was performed on 144 cases 156 eyes with 3.0mm corneal clear incision at the steepest corneal meridian. Preoperative corneal astigmatism and the data 3 months postoperatively were observed by the corneal topography system. Statistical analysis included sample Student's t-test, one way ANOVA test, Kruskal-Wallis test and Pearson correlation test.

RESULTS: According to analysis, the postoperative corneal astigmatism correlated negatively with the preoperative corneal astigmatism(r=-0.69, P<0.01). The corneal cylinder changed significantly in each grade after the surgery(P<0.05). When the preoperative corneal cylinder was between 0.12D and 0.25D, the postoperative corneal cylinder was higher than before. Whereas, the postoperative corneal cylinder became lower than before when the preoperative cylinder ranged from 0.37D to 1.0D.

CONCLUSION: The incision located at the steepest corneal meridian under the guidance of corneal topography changes the preoperative astigmatism. For astigmatic correction, 3.0mm on-axis clear corneal incision phacoemusification is recommended with preoperative corneal astigmatism between 0.37 and 1.0D.