高度近视眼睫状沟间距的差异性及其与角膜水平直径的相互关系

Discrepancy of sulcus-to-sulcus diameter and its relationship with white-to-white diameter in high myopic eyes

背景 水平睫状沟间距（STS）和角膜水平直径是选择可植入接触镜（ICL）型号大小的重要参考指标,尺寸和型号不合适的ICL可引起术后多种并发症.既往已有较多关于正常眼的相关研究,但高度近视眼的相关测量结果鲜有报道. 目的 探讨高度近视眼不同径线STS的差异性,研究不同测量仪器获得的水平STS与角膜水平直径的差异及其相互关系.方法 于2013年4-6月收集中山大学中山眼科中心拟行ICL植入术的高度近视眼患者26例48眼,平均球镜值为（-12.93±3.87）D,平均散光度为（-1.37±1.02）D.应用超声生物显微镜（UBM）测量受检眼45°、90°、135°、180°4个不同径线的STS,使用OrbscanⅡz角膜地形图和IOLMaster测量受检眼的角膜水平直径,不同径线间STS的总体差异比较采用单因素方差分析,两两比较采用SNK-q检验.采用Bland-Altman一致性检验法分析UBM测得的水平方向STS与OrbscanⅡz或IOLMaster测得的角膜水平直径的一致性. 结果 UBM测得的45°、90°、135°、180°径线方向上STS平均值分别为（12.06±0.50）、（12.27±0.50）、（12.03±0.46）和（11.84±0.47） mm.除45°径线与135°径线的STS之间差异无统计学意义（P=0.817）外,45°与90°、45°与180°、90°与135°、90°与180°、135°与180°径线STS之间的差异均有统计学意义（P=0.036、0.026、0.020、0.000、0.045）.OrbscanⅡz测得角膜水平直径为（11.56±0.40） mm,与180°水平径线的STS差异有统计学意义（t=-4.384,P=0.000）,Bland-Altman一致性分析显示两者结果一致性欠佳,95％可信区间（CI）为-0.57 ～ 1.12 mm.IOLMaster测得角膜水平直径为（11.98±0.41）mm,与180°水平径线的STS差异有统计学意义（t=2.368,P=0.000）,Bland-Altman一致性分析显示两者结果一致性欠佳,95％ CI为-0.96～0.67 mm.IOLMaster比ObrscanⅡz测得的角膜水平直径长,且差异有统计学意义（P=0.020）,两种仪器测量Bland-Altman一致性分析显示95％ CI范围虽然较窄,为-0.73 ～-0.13 mm,但是平均差值较大,为-0.43 mm,两者一致性较差.结论 高度近视眼不同径线方向上STS并不完全相等,垂直方向最长,水平方向最短.采用IOLMaster和OrbscanⅡz所测量的角膜水平直径推算UBM测量的STS并不准确.三者在临床上不能相互替代用于计算ICL型号的大小.

Background Horizontal sulcus-to-sulcus （STS） and white-to-white diameter are important parameters for designing the proper size of collamer implantable contact lens （ICL）.Inappropriate size of ICL may induce the complications postoperatively.Several previous studies compare horizontal STS and white-to-white diameter in normal eyes have been reported,but seldom in high myopic eyes.Objective This study was to investigate the discrepancy of STS diameters in 4 axes and analyze the relationship between horizontal STS diameter and white-towhite diameter in high myopia eyes.Methods The STS diameters in 4 axes （45,90,135 and 180 degrees） and the white-to-white diameters were measured in 48 eyes of 26 high myopia patients using the 50 MHz ultrasound biomicroscopy （UBM）,the Orbscan-Ⅱ topography system,and the IOL Master,respectively.The mean spherical was （-12.93±3.87） diopters （D） （-8 to-20 D）.Statistical evaluation was performed using the one-way ANOVA for comparison of measurement.The agreement of three devices was assessed using the Bland and Altman method.Results The mean STS diameter at 45,90,135 and 180 degrees was （12.06±0.50） mm,（12.27±0.50）mm,（12.03±0.46） mm and （11.84±0.47）mm,respectively.The 90 degree STS was significantly larger than other STS diameters （all at P＜0.05）.The 180 degrees STS was significantly shorter than other STS diameters （all at P＜0.05）.However,there was no significant difference between 45 degree STS and 135 degree STS （P=0.817）.The mean WTW was （11.56±0.40） mm with Orbscan Ⅱ z topography system and （11.98±0.41） mm with IOLMaster.The WTW measured with Orbscan Ⅱ z was significantly shorter than the 180 degrees STS （t =-4.384,P =0.000）.The WTW measured with IOLMaster was significantly larger than the 180 degrees STS （t =2.368,P =0.000）.Bland-Altman analysis showed not very well agreement for measurements of WTW,STS between Orbscan Ⅱz and UBM,IOLMaster and UBM,Orbscan Ⅱ z and IOLMaster,the width of 95％ confidence interval （CI） were-0.57 to 1.12 mm,-0.96 to 0.67 mm,-0.73 to-0.13 mm,respectively.Conclusions The STS diameters in 4 different axes are not identical with each other in high myopia eyes.The longest STS is in the vertical meridian,the shortest STS is in the horizontal meridian.The WTW diameter measured with both Orbscan Ⅱ z and IOLMaster are not precise for calculating the horizontal STS in high myopia eyes.Three instruments cannot be interchanged for calculating the size of ICL.