Background The different incisions in phacoemulsification,including the length,location and shape etc.,can cause surgery-induced astigmatism ( SIA ).But the SIA caused by 2.2 mm,3.0 mm corneal limbal incision after phacoemulsification,especially the change of posterior corneal surface astigmatism is still rarely reported. Objective This study was to investigate the anterior,posterior and total corneal SIA and compare their differences between phacoemulsification and foldable intraocular lens (IOL) implantation with 2.2 mm and 3.0 mm corneal limbal incisions. Methods Seventy-one eyes of 47 cases were randomly divided into two groups with matched age,visual acuity and astigmatism degree.Phacoemulsification and IOL implantation with 2.2 mm incision at the steepest corneal meridian was performed on the patients of 2.2 mm incision group,and the same surgery was adopted with 3.0 mm incision as 3.0 mm incision group.Corneal curvature radius and central corneal thickness were measured by Pentacam at 1 day before surgery and 1 week,1 month and 3 months after surgery respectively.The anterior and posterior corneal surface SIAs were calculated according to the flat axis and steep axis of corneal curvature and the air and the cornea refractive index.Based on the anterior and posterior surface SIAs,the total corneal SIA was then calculated using the vector analysis method.Jaffe/Clayman vector method was used to calculate the anterior and posterior and total corneal SIAs in the different time points,and the differences were compared between the two groups.Oral informed consent was obtained from each subject prior to the trial. Results The mean anterior and posterior surface corneal SIAs appeared to be lower in 2.2 mm incision group compared with 3.0 mm incision group at postoperative 1 day,1 week,1 month and 3 months but were not significantly different among groups at various time points ( anterior SIA:P =0.290 ; posterior SIA:P =0.740 ; total SIA:0.434 ).The mean anterior corneal surface SIAs were significantly lower at the postoperative 3 months than those at postoperative 1 day,1 week in both groups(2.2 mm incision group:P=0.020,0.036;3.0 mm incision group:P=0.006,0.023 ).The posterior corneal surface SIAs were (0.70±0.43 ) D and (0.75 ±0.54 ) D at 1 day in 2.2 mm incision group and 3.0 mm inscision group,respectively,and significantly decreased posterior corneal surface SIAs were found in postoperative 1 week,1 month and 3 months compared with 1 day in both groups ( 2.2 mm incision group:all P =0.001 ; 3.0 mm incision group:P=0.028,0.044,0.032).The total corneal surface SIA showed significant differences between 1 day and 1 week,1 month,3 months after surgery ( 2.2 mm incision group:P =0.015,0.002,0.002 ; 3.0 mm incision group:P =0.049,0.007,0.016 ). Conclusions There are no significant differences in the anterior,posterior and total corneal surface SIAs between 2.2 mm and 3.0 mm incisions after phacoemulsification with IOL implantation.The SIA is gradually reduced with the prolongation of postoperative time.%背景 白内障超声乳化术中切口的不同会引起不同的角膜手术源性散光已经被众多研究所证实,影响因素包括切口的长度、位置和形态等,但关于2.2 mm、3.0mm角膜缘切口白内障超声乳化手术引起的手术源性散光,尤其是引起的角膜后表面散光变化的研究国内外鲜有报道. 目的 对比经2.2 mm、3.0mm角膜缘切口的白内障超声乳化摘出联合人工晶状体(IOL)植入术后引起的角膜前表面、角膜后表面手术源性散光( SIA)值、总的SIA值及其变化.方法 将白内障患者47例71眼分成2.2mm切口组和3.0 mm切口组2个组,分别在角膜曲率最大子午线轴位做2.2 mm、3.0 mm角膜缘切口,行白内障超声乳化摘出联合IOL植入术.术前及术后1d、1周、1个月、3个月应用Pentacam系统测量角膜前表面、角膜后表面曲率及中央角膜厚度.根据角膜前表面平坦轴和陡轴方向的曲率半径及角膜前表面所在的空气和角膜本身的屈光指数计算角膜前表面散光值,以同样的方法计算角膜后表面的散光值,根据所得的角膜前表面、角膜后表面散光值,应用矢量法得出角膜总散光.使用Jaffe/Clayman分析法分别计算2个组患者不同时间点角膜前表面、角膜后表面SIA值和总SIA值,比较术后上述各时间点2个组间及2个组内SIA值的差别.结果 术后1d、1周、1个月及3个月2.2mm切口组白内障超声乳化摘出联合IOL植入术后平均角膜前表面、角膜后表面SIA值及总SIA值均低于3.0mm切口组,不同时间点组间的总体比较差异无统计学意义(前表面:P=0.290；后表面:P=0.740；总SIA:P=0.434).2个组术后3个月平均角膜前表面、角膜后表面散光值均明显低于术后1d和术后1周的散光值,差异均有统计学意义(2.2 mm切口组:P=0.020、0.036；3.0 mm切口组:P=0.006、0.023).术后1d时2.2mm切口组和3.0mm切口组术后角膜后表面散光值分别为(0.70±0.43)D和(0.75±0.54)D,而术后1周、1个月和3个月散光值均逐渐减少,与术后1d比较差异均有统计学意义(2.2mm切口组:均P=0.001；3.0 mm切口组:P=O.028、0.044、0.032).2个组术后1周、1个月、3个月的角膜总SIA值均明显低于术后1d值,差异均有统计学意义(2.2mm切口组:P=0.015、0.002、0.002；3.0mm切口组:P=O.049、0.007、0.016).结论 2.2mm和3.0 mm角膜缘切口超声乳化白内障摘出联合IOL植入术相比,前者SIA值相对较小但差异无统计学意义.对两组各个时间点的比较发现,角膜总的SIA值和后表面SIA值变化趋势基本一致,但与角膜前表面SIA值变化趋势不完全一致.
展开▼
