方法：将拟实施白内障超声乳化手术的硬核(Ⅳ级及以上)患者132眼根据手术切口的大小，分为2组。微切口组：2.2mm同轴微切口超声乳化白内障吸出联合人工晶状体植入术60眼； 传统切口组：3.0mm切口传统超声乳化白内障吸出联合人工晶状体植入术72眼。观察两组后囊破裂和术后角膜水肿的发生率； 记录两组超声乳化所用的平均超声能量(AVE)，术后1d； 1，3mo随访，记录视力，手术源性散光(SIA)，术后3mo检测角膜内皮细胞密度并计算丢失率。将相关数据进行统计学分析。

结果：后囊破裂和术后角膜水肿的发生率微切口组为3.3%，10.0%，传统切口组为4.2%，11.1%，差异无统计学意义。微切口组和传统切口组的平均超声能量分别为65.09±20.15，69.13±15.44，差异无统计学意义。术后1d平均裸眼视力微切口组优于传统切口组，差异有统计学意义(P<0.05)。术后1，3mo最佳矫正视力两组比较差别无统计学意义(P>0.05)。术后3mo角膜内皮细胞丢失率微切口组和传统切口组分别为(16.54±10.20)%，(17.69±10.65)%，差异无统计学意义。术后1d； 1，3mo微切口组手术源性散光分别为0.77±0.31，0.66±0.29，0.52±0.25D； 传统切口组分别为1.41±0.73，0.98±0.61，0.82±0.35D，差异有统计学意义。

结论：2.2mm同轴微切口超声乳化手术技术应用在硬核白内障病例中，具有与传统3.0mm切口相似的安全性； 能有效减少手术源性散光，对术后早期视力恢复具有优势。

METHODS: Totally 132 eyes with hard cataract(Ⅳ level and above)were randomized to two groups: 2.2mm MCCS(group 1:60 eyes)and 3.0mm MCCS(group 2:72 eyes). All patients underwent standard phacoemulsification and intraocular lens implantation surgery by one experienced surgeon. The average ultrasound power(AVE)was recorded during the operation. The incidences of capsule rupture and postoperative corneal edema were compared.Visual acuity, surgically induced astigmatism(SIA)and the descent rate of endothelial cell density were compared at intervals of 1 day, 1 month and 3 months after surgery. Statistic analysis was taken by Student's t test and Chi square test.

RESULTS: There was no significant difference on the incidences of capsule rupture, postoperative corneal edema and AVE(P> 0.05)between the two groups(3.3%, 10.0%, 65.09±20.15)and(4.2%, 11.1%, 69.13±15.44). One day after the surgery, the 2.2mm MCCS group showed better uncorrected visual acuity as compared to the 3.0mm MCCS group(P < 0.05). There were no significant differences on best-corrected visual acuity on 1 month and 3 months after the surgery. There was no significant difference on the descent rate of endothelial cell density(16.54%±10.20%, 17.69%±10.65%)3 months after the surgery. One day, 1 month and 3 months after the surgery, SIA was 0.77±0.31,0.66±0.29, 0.52±0.25D in the 2.2mm MCCS group, and 1.41±0.73,0.98±0.61D,0.82±0.35D in the 3.0mm MCCS group, respectively. The differences were statistically significant.

CONCLUSION: The operative safety of the 2.2mm MCCS group were the same as 3.0mm MCCS group with the hard nuclear cataracts. The 2.2mm MCCS phacoemulsification could significantly reduce SIA and get better earlier visual rehabilitation.