白内障患者角膜后表面散光的测量及相关因素分析

Measurement of posterior corneal astigmatism in the patients with cataract and its related factors

目的研究白内障患者角膜后表面散光(posterior corneal astigmatism,PA)的分布情况及相关影响因素。方法回顾性分析2017年1月至8月确诊为老年性白内障的患者174例(190眼),分为角膜前表面散光(anterior corneal astigmatism,AA)组:顺规散光组67例(75眼)、逆规散光组77例(80眼)、斜轴散光组32例(35眼)及总AA组174例(190眼);PA组:顺规散光组23例(23眼)、逆规散光组138例(149眼)、斜轴散光组18例(18眼)及总PA组174例(190眼)。术前通过Pentacam测得患者的角膜曲率、中央角膜厚度(central corneal thickness,CCT)、角膜水平直径(white-to-white,WTW),通过IOL Master测量患者的眼轴(axial length,AL)、前房深度(anterior chamber depth,ACD)。Bland-Altman分析模拟角膜散光值(simulated keratometry,SimK)与总角膜散光的差异;线性回归分析AA与PA的相关性;使用Pearson及Spearman相关分析其他眼内生物参数与PA的相关性。结果角膜SimK与总角膜散光的散光值及轴位差异均有统计学意义(均为P<0.05)。Bland-Altman显示95%一致性界限分别为-0.70~0.55 D、-63.4°~70.2°。顺规散光组AA与PA呈弱的正相关(r=0.316,P=0.005);逆规散光组PA与WTW呈弱的负相关(r=-0.214,P=0.015);而AL、CCT、ACD均与PA无明显相关性(均为P>0.05)。结论逆规性PA与WTW有弱的负相关,而PA与AL、ACD、CCT等参数没有相关性,且数值大小稳定。

Objective To investigate the distribution and related factors of posterior corneal astigmatism(PA)in the patients with cataract.Methods One hundred and seventy-four patients(190 eyes)with age-related cataract between January 2017 and August 2017 were retrospectively analyzed.They were divided into the anterior corneal astigmatism(AA)group:67 patients(75 eyes)in with-the-rule astigmatism group,77patients(80 eyes)in against-the-rule astigmatism group,32 patients(35 eyes)in oblique astigmatism group,and PA group:23patients(23 eyes)in with-the-rule astigmatism group,138 patients(149 eyes)in against-the-rule astigmatism group,18 patients(18 eyes)in oblique astigmatism group.Preoperative corneal curvature,central corneal thickness(CCT),and horizontal corneal diameter(WTW)were measured by Pentacam.Axial length(AL)and anterior chamber depth(ACD)were measured by IOL Master.The difference between simulated keratometry(SimK)and total corneal astigmatism was analyzed by Bland-Altman.The correlation between AA and PA was analyzed by linear regression analysis.The correlation between other intraocular biological parameters and PA was analyzed by Pearson or Spearman analysis.Results There was significant difference about astigmatism value and axis between SimK and total corneal astigmatism(all P<0.05).Bland-Altman showed that the range of 95%limit of agreement was(-0.70-0.55)D,-63.4°-70.2°,respectively.There was a weak positive correlation between AA and PA in with-the-rule astigmatism group(r=0.316,P=0.005).The correlation between PA and WTW in against-the-rule group had a weak negative correlation(r=-0.214,P=0.015).The AL,CCT and ACD were not significantly correlated with the PA,respectively(all P>0.05).Conclusion PA in against-the-rule group was negatively correlated with WTW,while there was no correlation among AL,ACD,CCT,and the values were stable.