白内障超声乳化术3.2mm透明角膜切口术源性散光的分析

Analysis of astigmatism induced by phacoemulsification with 3.2mm clear corneal incision

目的:计算并比较不同位置3.2mm透明角膜切口白内障超声乳化吸出联合人工晶状体植入术的手术源性散光(surgery induced astigmatism,SIA)的度数,分析切口对角膜曲率的影响。方法:将88例100眼随机分为A,B两组,A组做颞侧(9∶00或者3∶00方位)透明角膜3.2mm斜形切口,B组做上方12∶00方位透明角膜斜形切口,行白内障超声乳化吸出联合折叠人工晶状体植入术,测量术前和术后3mo的角膜曲率,用矢量分析法计算SIA度数,比较两组SIA度数的差异,同时分别比较切口所在子午线、与切口垂直子午线术前和术后角膜曲率的变化。结果:两组平均SIA度数比较,差异无显著性(P=0.483),切口所在子午线术前和术后角膜曲率比较,差异有显著性(P=0.006),而与切口垂直子午线的术前和术后角膜曲率比较差异无显著性(P=0.084)。结论:3.2mm透明角膜切口SIA的度数与切口位置无明显关系,切口对所在子午线角膜曲率有松解作用,对与切口垂直子午线角膜曲率无明显影响,矢量公式法计算所得的SIA值在散光型人工晶状体植入术中提供了重要的参考价值。

AIM： To calculate and compare the degrees of surgery induced astigmatism （SIA） in phacoemulsification and intraocular lens （IOL） implantation with 3.2mm clear corneal incision in different positions and to analyze the effect of incision on corneal curvature. METHODS： Eighty-eight cases 100 eyes were randomly divided into two groups： group A with incision at temporal （9∶00 or 3∶00） clear corneal,group B with incision at superior （12∶00） clear corneal. All patients underwent phacoemul- sification and foldable acrylic IOL implantation. Corneal curvature radius was obtained at preoperative and postoperative 3 months. The SIA degrees were analyzed by Jaffe/Clayman vector method. We compared SIA degrees between groups, corneal curvature at incision meridian and at another meridian between preoperative and postoperative. RESULTS： The mean SIA degrees between two groups showed no significant difference （P=0.483）. There was significant difference（P=0.006） between preoperative and postoperative corneal curvature at incision meridian. There was no significant difference（P=0.084） between preoperative and postoperative corneal curvature at another meridian. CONCLUSION： SIA degree in phacoemulsification with 3.2mm clear corneal incision has no connection with incision positions. Corneal curvature at incision meridian will be released, but another meridian has no distinct effect. The SIA analyzed by Jaffe/Clayman vector method will provide an important reference for toric IOL implantation surgery.