Hayek S, Kniestedt C, Barthelmes D, Stürmer J
Augenklinik, Universitätsspital Zürich, Schweiz.
Klin Monbl Augenheilkd. 2007 Apr;224(4):244-8. doi: 10.1055/s-2007-962961.
An important factor for patient satisfaction after cataract surgery is the achievement of the planned target refraction. The formulae which are used to calculate the necessary refractive power of the intraocular lens (IOL) to be implanted have been improved over time in order to deliver exact predictions even in those cases in which the measurements of an eye deviate greatly from the norm. We examined which of the routinely measured biometric values have an influence on reaching target refraction.
This retrospective investigation reports on a case series of 153 eyes of 146 patients within 6 months in which a cataract operation was performed. The average age at the time of operation was 73.5 years. Four measurements were taken preoperatively: refraction (Ref), axial length (AL), corneal refractive power (CR) and anterior chamber depth (ACD). Each of these measurements was examined regarding its influence on the refractive outcome. One of three end points was possible for each eye: achievement of target refraction within +/- 0.5 dpt, aberrance from target refraction by more than + 0.5 dpt and aberrance from target refraction by more than - 0.5 dpt. A multivariate regression analysis was performed in which aberrance from target refraction was defined as the dependent variable and the four mentioned measurements were set as independent variables.
Of the 153 eyes, in 91 eyes the target refraction was achieved within 0.5 dpt (group 1). In 37 eyes the aberrance from target refraction was more than - 0.5 dpt (group 2) and in 25 eyes it was more than + 0.5 dpt (group 3). The mean measurement values in groups 1, 2 and 3 were as follows: for preoperative refraction 0.0 dpt/0.5 dpt/0.625 dpt, for corneal refractive power 42.84 dpt/42.29 dpt/42.67 dpt, for axial length 23.41 mm/23.36 mm/23.73 mm and for anterior chamber depth 3.07 mm/3.00 mm/3.20 mm. No statistically significant relation between the respective measured values or a combination thereof and the refractive result could be demonstrated.
The formulae for calculating IOL power available today are highly developed and integrate preoperative biometries in a non-linear way, so that there is little difference between measurements within the norm and outlying ones concerning their influence on the refractive result. When conducting quality assurance efforts, we recommend to direct attention to factors influencing anterior chamber depth.
白内障手术后患者满意度的一个重要因素是实现计划的目标屈光。随着时间的推移，用于计算拟植入人工晶状体（IOL）所需屈光力的公式已得到改进，以便即使在眼睛测量值与正常情况有很大偏差的情况下也能做出准确预测。我们研究了哪些常规测量的生物特征值会影响达到目标屈光。
这项回顾性研究报告了146例患者在6个月内进行白内障手术的153只眼的病例系列。手术时的平均年龄为73.5岁。术前进行了四项测量：屈光（Ref）、眼轴长度（AL）、角膜屈光力（CR）和前房深度（ACD）。对这些测量中的每一项都研究了其对屈光结果的影响。每只眼可能出现三个终点之一：在±0.5屈光度内实现目标屈光、偏离目标屈光超过+0.5屈光度以及偏离目标屈光超过 - 0.5屈光度。进行了多变量回归分析，其中将偏离目标屈光定义为因变量，并将上述四项测量设置为自变量。
在153只眼中，91只眼在0.5屈光度内实现了目标屈光（第1组）。37只眼偏离目标屈光超过 - 0.5屈光度（第2组），25只眼偏离目标屈光超过+0.5屈光度（第3组）。第1、2和3组的平均测量值如下：术前屈光为0.0屈光度/0.5屈光度/0.625屈光度，角膜屈光力为42.84屈光度/42.29屈光度/42.67屈光度，眼轴长度为23.41毫米/23.36毫米/23.73毫米，前房深度为3.07毫米/3.00毫米/3.20毫米。未发现各测量值或其组合与屈光结果之间存在统计学上的显著关系。
当今可用的计算IOL屈光力的公式已经高度发达，并以非线性方式整合术前生物特征测量，因此正常测量值与异常测量值对屈光结果的影响几乎没有差异。在进行质量保证工作时，我们建议关注影响前房深度的因素。
