Liang J L, Xing X L, Yang X T, Jiang Y F, Zhang H
Tianjin Medical University Eye Hospital, College of Optometry and Ophthalmology, Tianjin Medical University Eye Institute, Tianjin 300384, China.
Zhonghua Yan Ke Za Zhi. 2019 Jul 11;55(7):495-501. doi: 10.3760/cma.j.issn.0412-4081.2019.07.004.
To compare the surgical induced astigmatism(SIA) of the total, anterior and posterior cornea between eyes with 2.2-mm and 3.0-mm clear corneal incisions in phacoemulsification. A prospective double-blind randomized controlled study was conducted on 131 patients (131 eyes) with age-related cataract from October 2017 to June 2018. They were randomized according to the random number table. Sixty-nine patients received phacoemulsification through a 2.2-mm clear corneal incision at 140 degrees; 62 patients were recruited in the control group with a 3.0-mm clear corneal incision at the same position. Lens density was graded and compared between the groups preoperatively. Total corneal refractive power (TCRP), simulated keratometry (SimK) and posterior corneal astigmatism (PCA) (Apex, 4-mm zone) were recorded through the Pentacam preoperatively and at 1 week, 1 month and 3 months postoperatively. Corneal astigmatism was decomposed to vertical/horizontal (X) and oblique changes (Y) using the power vector analysis. Independent sample test and matched test were used for statistical analysis. A total of 123 patients (123 eyes) completed 3 months of follow-up including 65 in the 2.2-mm group and 58 in the control group. The age of the two groups was (69±9) and (71±10) years old, and the lens density was (2.08±0.47) and (2.12±0.46) grades, respectively. Both the age and the lens density of the two groups were not statistically significant (both 0.05). Preoperative TCRP, SimK and PCA were not statistically significant (all 0.05). SIA was calculated using the vector analysis. Centroid SIA conducted from TCRP, SimK and PCA in the 2.2-mm group was -0.11 D@146°, -0.11 D@151° and -0.03 D@67°, respectively, at 3 months postoperatively. In the 3.0-mm group, it was -0.25 D@158°, -0.24 D@147° and -0.04 D@47°, respectively. Statistical significance was found between the two groups in the Y polar value of SIA of the anterior surface [(-0.10±0.30) (-0.22±0.37) D, -2.133, 0.035] and the SIA of the posterior surface [(0.24±0.16) (0.19±0.12) D, 2.009, 0.047] at 3 months postoperatively. In the comparison of the SIA of TCRP and anterior surface, statistical significance was found in the absolute value of SIA at all the intervals in the 2.2-mm group [(0.87±0.80) (0.58±0.48) D, (0.58±0.48) (0.50±0.28)D, (0.57±0.37) (0.47±0.28) D, 5.102, 4.155, 3.877, all 0.01] and at 1 week and 1 month in the 3.0-mm group [(0.82±0.57) (0.58±0.41) D, (0.59±0.36) (0.50±0.28) D, 5.034, 3.919, both 0.01]. X components of SIA(TCRP) and SIA(simk) were significantly different at 3 month postoperatively in 3.0-mm group (0.05). Y components of SIA(TCRP) and SIA(SimK) were significantly different at 1 week postoperatively in the 2.2-mm group[(-0.48±0.85) (-0.24±0.42) D, 0.01] and 3.0-mm group [(-0.58±0.66) (-0.37±0.42) D, 0.01]. Compared with the 3.0-mm incision, the 2.2-mm coaxial micro-incision cataract surgery has a lower and more stable SIA. The effect of a clear corneal incision in cataract surgery on the total cornea is more obvious than that on the anterior surface of the cornea. The difference is significant in the early stage and gradually decrease with time. -.
比较白内障超声乳化手术中2.2mm和3.0mm透明角膜切口眼的全角膜、角膜前表面和后表面的手术诱导散光（SIA）。2017年10月至2018年6月对131例年龄相关性白内障患者（131只眼）进行前瞻性双盲随机对照研究。根据随机数字表将患者随机分组。69例患者在140度方向通过2.2mm透明角膜切口行超声乳化手术；62例患者作为对照组，在相同位置行3.0mm透明角膜切口手术。术前对两组晶状体密度进行分级并比较。术前及术后1周、1个月和3个月通过Pentacam记录全角膜屈光力（TCRP）、模拟角膜曲率（SimK）和后角膜散光（PCA）（顶点，4mm区域）。采用屈光力矢量分析法将角膜散光分解为垂直/水平（X）和斜向变化（Y）。采用独立样本t检验和配对t检验进行统计分析。共有123例患者（123只眼）完成了3个月的随访，其中2.2mm组65例，对照组58例。两组患者年龄分别为（69±9）岁和（71±10）岁，晶状体密度分别为（2.08±0.47）级和（2.12±0.46）级。两组患者年龄和晶状体密度差异均无统计学意义（均P>0.05）。术前TCRP、SimK和PCA差异均无统计学意义（均P>0.05）。采用矢量分析法计算SIA。术后3个月，2.2mm组由TCRP、SimK和PCA得出的质心SIA分别为-0.11D@146°、-0.11D@151°和-0.03D@67°。3.0mm组分别为-0.25D@158°、-0.24D@147°和-0.04D@47°。术后3个月，两组前表面SIA的Y极向值[（-0.10±0.30）（-0.22±0.37）D，t=-2.133，P=0.035]和后表面SIA[（0.24±0.16）（0.19±0.12）D，t=2.009，P=0.047]差异有统计学意义。在TCRP和前表面SIA的比较中，2.2mm组各时间点SIA绝对值差异有统计学意义[（0.87±0.80）（-0.58±0.48）D，（0.58±0.48）（0.50±0.28）D，（0.57±0.37）（0.47±0.28）D，t值分别为5.102、4.155、3.877，均P<0.01]，3.0mm组在术后1周和1个月差异有统计学意义[（0.82±0.57）（0.58±0.41）D，（0.59±0.36）（0.50±0.28）D，t值分别为5.034、3.919，均P<0.01]。3个月时，3.0mm组SIA（TCRP）和SIA（simk）的X分量差异有统计学意义（P<0.05）。术后1周，2.2mm组[（-0.48±0.85）（-0.24±0.42）D，P=0.01]和3.0mm组[（-0.58±0.66）（-0.37±0.42）D，P=0.01]SIA（TCRP）和SIA（SimK）的Y分量差异有统计学意义。与3.0mm切口相比，2.2mm同轴微切口白内障手术的SIA更低且更稳定。白内障手术中透明角膜切口对全角膜的影响比对角膜前表面的影响更明显。差异在早期显著，随时间逐渐减小。
