Kalogeropoulos C, Aspiotis M, Stefaniotou M, Psilas K
University Eye Clinic of Ioannina, Greece.
Doc Ophthalmol. 1994;85(3):223-42. doi: 10.1007/BF01664930.
Several intraocular lens (IOL) power calculation formulas (either theoretical or empirical) are used to determine the emmetropic IOL power) The Sanders-Retzlaff-Kraff (SRK) linear regression formula is among the most widely recognized empirical ones. In the present study intraocular lens power calculation aiming at emmetropia was performed, using SRK formula, in 145 cataractous eyes undergoing lens implantation. The final refraction was evaluated at 8 to 12 months after surgery. The purpose of this study was the identification and quantitative evaluation of the factors which influence significantly the accuracy of SRK in the intraocular lens power calculation. The following factors were studied: (1) the error in preoperative biometry with regard to the difference between post and preoperative axial length measurements, (2) the position of the implantation of the intraocular lens (anterior versus posterior chamber), (3) the intraocular lens style, (4) the intraocular lens power level, (5) the preoperative corneal astigmatism, (6) the surgically induced corneal astigmatism, and (7) the postoperative astigmatism. Multiple regression and stepwise regression analysis showed a strong correlation (R2 = 0.65; p < 0.001) between postoperative refractive error (Rf) and error in preoperative biometry (delta AL), surgically induced corneal astigmatism (SIA) and postoperative astigmatism (Ap) only. This correlation is expressed by the following equation: Rf = 0.07 -2.55 delta AL -0.42 SIA + 0.34 Ap. This equation indicates the quantitative effect of each factor on the accuracy of the SRK formula, by defining the pattern of the fluctuations of the amount or state (myopic or hyperopic) of refractive error induced by changes of variables delta AL, SIA and Ap.
有几种人工晶状体（IOL）屈光力计算公式（理论公式或经验公式）可用于确定正视眼的人工晶状体屈光力。桑德斯 - 雷茨拉夫 - 克拉夫（SRK）线性回归公式是最广为人知的经验公式之一。在本研究中，对145只接受晶状体植入的白内障眼，使用SRK公式进行了旨在实现正视眼的人工晶状体屈光力计算。术后8至12个月评估最终屈光状态。本研究的目的是识别并定量评估显著影响SRK公式在人工晶状体屈光力计算中准确性的因素。研究了以下因素：（1）术前生物测量的误差，即术后与术前眼轴长度测量值的差异；（2）人工晶状体的植入位置（前房与后房）；（3）人工晶状体的类型；（4）人工晶状体的屈光力水平；（5）术前角膜散光；（6）手术引起的角膜散光；（7）术后散光。多元回归和逐步回归分析显示，术后屈光误差（Rf）仅与术前生物测量误差（ΔAL）、手术引起的角膜散光（SIA）和术后散光（Ap）之间存在强相关性（R2 = 0.65；p < 0.001）。这种相关性由以下方程表示：Rf = 0.07 - 2.55ΔAL - 0.42SIA + 0.34Ap。该方程通过定义由变量ΔAL、SIA和Ap的变化引起的屈光误差量或状态（近视或远视）波动模式，表明了各因素对SRK公式准确性的定量影响。
