两种不同角膜缘切口对白内障超声乳化吸除术后角膜术源性散光的影响对比

Clinical comparison analysis in the influence of different width corneal limbal incisions on the surgical induced astigmatism of the total,anterior and posterior cornea after cataract surgery

目的比较2.2 mm与3.0 mm的角膜缘切口对白内障超声乳化吸除术后全角膜、角膜前表面和角膜后表面的手术源性散光(SIA)影响的差异。方法将103例(103只眼)白内障患者分为2.2 mm组74例(74只眼)与3.0 mm组29例(29只眼),在角膜10:30位做单平面角膜缘切口后行常规白内障超声乳化吸除联合人工晶状体(IOL)植入术,术后3个月应用Sirius三维眼前节分析系统测量以角膜顶点为中心3 mm、5 mm直径区域内的全角膜散光值(TCA)、SimK值、3 mm、5 mm直径区域内的角膜前表面散光值(ACA)、后表面散光值(PCA),使用矢量分析法分解散光为X-Y径线,通过公式计算得出质心SIA(Centroid SIA),并采用Sigma Plot软件进行绘图。结果术后3个月2.2 mm组、3.0 mm组对于全角膜、角膜前表面和角膜后表面产生的SIA的算术平均值无统计学意义(均P>0.05);靶点图显示3.0 mm组的SIA的散点位置较2.2 mm组更为分散,提示2.2 mm组切口更稳定。术后3个月2.2 mm组通过3 mm直径区域TCA计算得出的SIA高于SimK及相同区域ACA计算得出的SIA,差异有统计学意义(P<0.001),5 mm直径区域TCA计算得出的SIA高于通过SimK计算得出的SIA,差异有统计学意义(P<0.01)。5 mm直径区域TCA计算得出的SIA虽然也高于相同直径区域ACA的SIA,然而差异并无统计学意义(P=0.072),2.2 mm组在直径5 mm区域内X径线上TCA计算得出的SIA大于ACA的SIA,差异有统计学意义(P<0.05),而Y径线上差异并无统计学意义(均P>0.05),此外,在直径3 mm区域内的X径线及Y径线TCA与SimK、ACA计算得出的SIA差异也均无统计学意义(均P>0.05)。3.0 mm组通过不同直径区域TCA计算得出的SIA与SimK、ACA计算得出的SIA相比并无显著差异,其X径线及Y径线的SIA差异也无统计学意义(均P>0.05)。结论3.0 mm较2.2 mm的角膜缘切口在全角膜、角膜前表面产生更大的Centroid SIA,且2.2 mm角膜缘切口对全角膜SIA的影响大于角膜前表面SIA。

Objective This study was to compare the surgical induced astigmatism(SIA)of the total,anterior and posterior cornea after cataract surgery with 2.2 mm and 3.0 mm corneal limbal incisions.Methods 103 cataract patients were randomly divide into 2.2 mm group(74 eyes in 74 cases)and 3.0 mm(29 eyes in 29 cases),participants underwent a conventional phacoemulsification combined with intraocular lens(IOL)implantation with a single plane corneal limbal incisions at 10:30.Total corneal astigmatism(TCA)(Apex,3 mm and 5 mm),Sim K,anterior corneal astigmatism(ACA)and posterior corneal astigmatism(PCA)(Apex,3 mm and 5 mm)were recorded through the Sirius preoperatively and three months postoperatively.The astigmatism was decomposed to X-Y radial lines using the vector analysis method,and the centroid SIA was calculated by the formula,and the Sigma Plot 14.0 software was used to draw the target map.Result Neither the arithmetic mean of SIA nor Centroid SIA calculated by TCA(Apex,3 mm and 5 mm),SimK,ACA and PCA(Apex,3 mm and 5 mm)were statistical differences(all P>0.05)at three months after surgery.Compared with 2.2 mm group,3.0 mm group produced larger centroid SIA on the total cornea and anterior corneal surface.The target map showed that the scatter location of SIA in 3.0 mm group was more dispersed than that in 2.2 mm group,suggesting that the 2.2 mm incision group was more stable.In the 2.2 mm group,the SIA calculated by TCA(Apex,3 mm)was higher than that calculated by SimK and ACA in the same area,the difference was statistically significant(P<0.001),the SIA calculated by TCA(Apex,5 mm)was higher than that calculated by SimK in the same area,the difference was statistically significant(P<0.01).Although the SIA calculated by TCA(Apex,5 mm)was also higher than that of ACA in the same diameter area,the difference was not statistically significant(P=0.072),the SIA of TCA(Apex,5 mm)in X-component was higher than that of ACA,the difference was statistically significant(P<0.05),while the difference on Y-component was not statistically significant(P>0.05).In addition,in the 3.0 mm group,there was no significant difference in SIA(both X-component and Y-component)between TCA and SimK,ACA(P>0.05).Conclusion The 3.0 mm limbal incision produced larger centroid SIA on the total cornea and anterior cornea surface than the 2.2 mm limbal incision.The effect of 2.2 mm limbal incision on total corneal SIA is greater than that of anterior corneal surface SIA.