放射状角膜切开术后人工晶状体度数计算方法选择的临床研究

Clinical study on the selection of intraocular lens power calculation methods after radial keratotomy

目的评价Barrett True-K公式法、Shammas公式法、Haigis公式法应用于放射状角膜切开(RK)术后的白内障患者人工晶状体(10L)的屈光准确性。设计回顾性病例系列。研究对象2017年1月至2024年2月北京同仁医院RK术后白内障患者28例(49眼)。方法术前应用IOLMaster获得患者各项眼前节参数,使用SRK/T公式法、Shammas公式法或Barrett True-K公式法计算IOL屈光度,术后1个月显然验光检查术眼屈光状态,并记录等效球镜度数,为术后实际屈光度。登录美国屈光协会网站(www.ascrs.org),应用Barrett True-K公式法、Shammas公式法、Haigis公式法,代人术后实际屈光度及IOLMaster测量所得数据,计算各公式预测IOL屈光度,然后使用实际植入IOL屈光度减去各公式预测IOL屈光度,记为IOL屈光度的屈光误差,其绝对值记为绝对屈光误差。主要指标屈光误差及绝对屈光误差。结果术后1个月,28例(49眼)的BarrettTrue-K公式法屈光误差为0.13(-0.750.89)D,明显低于Shammas公式法的-1.20(-1.94,-0.54)D、Haigis公式法的-1.59(-2.54,-0.49)D(S=39.837,P<0.001);BarrettTrue-K公式法绝对屈光误差为0.79(0.39,1.58)D,低于Shammas公式的1.21(0.57,1.94)D、Haigis公式法的1.59(0.492.54)D(S=9.959,P=0.007)。对于所有28例(49眼),BarrettTrue-K公式法的屈光误差在±0.5D、±1.0D、±2.0D范围者分别占39%、67%、96%,Shammas公式法分别占29%、51%、88%,Haigis公式法分别占33%、43%、80%。其中届光误差在±1.0D(χ^(2)=6.130,P=0.047)、±2.0D(χ^(2)=6.078,P=0.048)范围内,三个公式之间的差异具有统计学意义。BarrettTrue-K公式法屈光误差绝对值与眼轴长度呈负相关(r=-0.397,P=0.008)。对于术前应用BarrettTrue-K公式法计算I0L屈光度者(19例,33眼),BarrettTrue-K公式法屈光误差为0.30(-0.78,1.56)D,明显低于Shammas公式法的-1.18(-1.77,-0.59)D、Haigis公式法的-1.31(-2.46,-0.34)D(S=28.42,P<0.001);BarrettTrue-K公式法屈光误差绝对值与Shammas公式法和Haigis公式法差异无统计学意义(S=3.697,P=0.157);在术前应用BarrettTrue-K公式法计算IOL屈光度者,BarrettTrue-K公式法屈光误差在+0.5D、±1.0D、±2.0D范围者分别占24%、61%、97%,Shammas公式法分别占15%、42%、87%,Haigis公式法分别占30%、39%、64%;BarrettTrue-K公式法光误差在±2.0D内的占比多于Shammas公式法及Haigis公式法(χ^(2)=13.778,P=0.001)。结论对于放射状角膜切开手术后的白内障患者,Barrett True-K公式法与Shammas公式法、Haigis公式法之间的准确性存在一定差异,Barrett True-K公式法可获得更好的屈光结果。BarrettTrue-K公式法的屈光误差绝对值与眼轴长度呈负相关。

Objective To evaluate the accuracy of Barrett True-K formula,Shammas formula and Haigis formula in the intraocular lens(IOL)of cataract patients after radial keratotomy(RK).Design Retrospective case series.Participants 28 patients(49 eyes)diag-nosed with cataracts after RK at Beijing Tongren Hospital from January 2017 to February 2024.Methods IOL Master was used to ob-tain the parameters of the anterior segment of the patient before surgery.SRK/T formula,Shammas formula or Barrett True-K formula were used to calculate IOL diopter before surgery.The refractive status of the eye was obviously checked by optometry one month after surgery.The actual diopter was recorded by equivalent spherical(SE).Log on to the official website of American Refractive Association(www.ascrs.org)and apply Barrett True-K formula,Shammas formula and Haigis formula to calculate the predicted IOL diopter by re-placing the actual postoperative diopter and the measured data of IOL Master.Then the actual implanted IOL diopter was subtracted from each formula to predict IOL diopter,denoted as IOL diopter error,and its absolute value was denoted as absolute diopter error.Main Outcome Measures Refractive error and absolute refractive error.Results For the 28 patients(49 eyes)included in the study,the refractive error of Barrett True-K formula method was 0.13(-0.75,0.89)D at one month after surgery,which was significantly lower than that of Shammas formula method-1.20(-1.94,-0.54)D,Haigis formula method-1.59(-2.54,-0.49)D(S=39.837,P<0.001).The absolute refractive error of Barrett True-K formula method was 0.79(0.39,1.58)D,which was lower than that of Shammas formula method 1.21(0.57,1.94)D and Haigis formula method 1.59(0.49,2.54)D(S=9.959,P=0.007).In all 28 patients(49 eyes),Barrett True-K formula method accounted for 39%,67% and 96% of refractive errors in the range of±0.5 D,±1.0 D and±2.0 D,respectively.Shammas formula method accounted for 29%,51%,88%,and Haigis formula method accounted for 33%,43%,80%,respectively.The difference of refractive error between the three formulas in the range of±1.0 D(χ^(2)=6.130,P=0.047)and±2.0 D(χ^(2)=6.078,P=0.048)was statistically significant.The absolute refractive error of Barrett True-K formula was negatively correlated with the axial length of the eye(r=-0.397,P=0.008).For patients(19 cases,33 eyes)who applied Barrett True-K formula method to calculate I0L diopter before surgery,the diopter error of Barrett True-K formula method was 0.30(-0.78,1.56)D,which was significantly lower than that of Shammas formula method-1.18(-1.77,-0.59)D,-1.31(-2.46,-0.34)D(S=28.42,P<0.001)for Haigis formula method.There was no statistical significance in the absolute refractive error of Barrett True-K formula compared with Shammas formula and Haigis formula(S=3.697,P=0.157).In the patients with IOL diopter calculated by Barrett True-K formula before surgery,Barrett True-K formula method accounted for 24%,61%and 97%of refractive errors in the range of±0.5 D,±1.0 D and±2.0 D,respectively.Shammas formula method accounted for 15%,42%and 87%.Haigis formula method accounted for 30%,39%and 64%,respectively.The proportion of refractive error of Barret True-K formula method within±2.0 D was higher than that of Shammas formula method and Haigis formula method(χ^(2)=13.778,P=0.001).Conclusion For cataract patients after RK,there are some differences in the accuracy of Barrett True-K formula method,Shammas formula method and Haigis formula method.The absolute refractive error of Barret True-K formula method is negatively correlated with the length of the axis of the eye,that is,the longer the axial length of the eye,the lower the absolute refractive error and the higher the accuracy.