角膜缘松解切开术矫正白内障术前散光对角膜曲率的影响

Changes of corneal curvature following phacoemulsification combined with limbal relaxing incisions on correction of astigmatism

目的观察角膜缘松解切开术在白内障超声乳化术中对角膜散光的矫正效果,以及其对角膜前后表面的中央曲率、周边曲率的影响。方法选取在我院诊治的白内障患者35例35眼,患者术前角膜散光均≥1.0 D,行角膜缘松解切开术联合白内障超声乳化吸出+人工晶状体植入术,所有患者均在术前及术后1 d、1周、1个月、3个月进行眼科常规检查,包括术眼裸眼视力(uncorrected visual acuity,UCVA)、最佳矫正视力(best corrected visual acuity,BCVA),进行显然验光,用Pentacam眼前节分析系统测量角膜前后表面中央3 mm范围内的最大曲率、最小曲率,同一子午线上角膜前后表面周边7 mm范围最大及最小曲率。比较患者术前及术后各时间点UCVA、BCVA、中央及周边角膜前后表面曲率的变化。结果患者术后不同时间点的UCVA及BCVA与术前比较均显著提高,术前UCVA>0.5占0%,BCVA>0.5占8.6%,而术后3个月UCVA>0.5占42.9%,BCVA>0.5占77.1%,差异均有统计学意义(均为P<0.001);术后各时间点与术前相比,最佳矫正柱镜度数和角膜散光均减少,差异均有统计学意义(均为P<0.001);前表面角膜中央和周边曲率与术前相比,早期均是陡峭轴曲率呈减小趋势,扁平轴曲率呈增加趋势,之后稳定(P<0.05),中央陡峭曲率FK2减少了(1.06±0.66)D,周边陡峭曲率FPK2减少了(0.76±0.50)D,中央平坦曲率FK1增加了(0.33±0.28)D,周边平坦曲率FPK1增加了(0.35±0.26)D。角膜后表面中央及周边曲率与术前比较有变化,但没有明显规律性。结论角膜缘松解切开术矫正白内障术前角膜散光是安全有效的,松解切开术会引起角膜前后表面中央曲率和周边曲率的变化,且前表面中央曲率变化对角膜散光的影响较大,后表面曲率变化对角膜散光的影响很小。

Objective To observe the effects of phacoemulsification combined with limbal relaxing incisions on correcting the corneal astigmatism,and investigate its effects on corneal curvature. Methods A total of 3 5 patients 3 5 eyes with preoperative corneal astigmatism ≥1. 0 D received limbal relaxing incisions during cataract operations. The uncorrected visual acuity（ UCVA） and best corrected visual acuity（ BCVA） were examined at pre-operation and postoperative 1 day,1 week,1 month,3 months. A rotating Scheimpflug camera,also called Pentacam（ Typ7 0 7 0 0,Germany） was used to measure the corneal central and periphery curvature on 3 mm and 7 mm diameter at pre-operation and postoperative 1 day,1 week,1 month,3 months. Results UCVA and BCVA at postoperative 1day,1 week,1 month,3 months were all higher than pre-operation,no UCVA was 0. 5 and BCVA 0. 5 was only 8. 6 % before operation,but at post-operation UCVA 0. 5was 4 2. 9 % and BCVA 0. 5 was 7 7. 1 %,there were significant differences（ all P 0.0 0 1）. The refractive cylindrical error and corneal astigmatism were decreased significantly at postoperative 1 day,1 week,1 month,3 months compared with pre-operation,there were significant differences（ all P 〉0. 0 0 1）. The steep curvature of anterior corneal surface was decreased and the flat curvature was increased at the early stage,then keep steady（ P 〉0. 0 5）; The central steep curvature of anterior corneal surface was decreased（ 1. 0 6 ±0. 6 6） D,the peripheral steep curvature of anterior corneal surface was decreased（ 0. 7 6± 0. 5 0） D,the central flat curvature of anterior corneal surface was increased（ 0. 3 3 ± 0.2 8） D and the peripheral flat curvature of anterior corneal surface was increased（ 0. 3 5 ±0. 2 6） D. Otherwise the curvature of posterior corneal surface had no regular change. Conclusion Phacoemulsification combined with limbal relaxing incisions can reduce the corneal astigmatism effectively and safely. The limbal relaxing incisions can change the corneal curvature. Changing the curvature of anterior corneal surface play a leading role on correcting corneal astigmatism,and the change of posterior corneal surface has little effect on corneal astigmatism.