多功能人工晶状体计算公式的设计与检验

Design and inspection of multifunctional intraocular lens calculation formula

目的建立适应眼球数据宽泛常规人工晶状体（IOL）计算公式和用于准分子激光角膜原位磨镶术（LASIK）术后眼的IOL计算公式。方法采用系列病例研究。依据经典的光学理论，正视状态IOL植入眼具备：光线经角膜折射，到达IOL平面时的屈光力（F1）＋IOL屈光力（F2）＝适合玻璃体腔距离的屈光力（F3）。此后，按IOL植入术后的理论、经验和回归分析数据建立数学模型；又按LASIK术后眼的角膜曲率修正公式编制常规和LASIK术后2种IOL计算程序，并经南京鼓楼医院白内障摘出联合后房型IOL植入术后644例患者[600眼生理角膜眼、7眼角膜放射状切开（RK）术后眼、37眼LASIK术后眼]资料的检验。结果本研究公式（暂定名：XLQ公式）包括RK术后眼在内的607眼IOL值平均误差为0.1 D，95%一致性界限为－1.1～＋1.2 D。XLQ公式、SRK-T公式和Haigis公式预测的IOL值误差范围分别为－2.21～＋2.25 D、－5.10～＋5.63 D和－3.00～＋3.18 D，IOL值绝对平均误差分别为（0.43±0.28）、（0.74±0.53）和（0.79±0.49）D，XLQ公式分别与SRK-T、Haigis公式比较，差异均有统计学意义（均P＝0.000）。XLQ公式预测的IOL误差值与眼轴长度（AL）、K、A常数均无相关性（均P〉0.05），SRK-T公式、Haigis公式预测的IOL误差值与AL、K、A常数均有相关性（均P〈0.05）。XLQ公式预测的近视LASIK术后眼中参与回访者37例，IOL值预测误差范围为－0.52～＋1.18 D，IOL值绝对平均误差为（0.49±0.26）D。结论 XLQ公式的常规模式适应的AL、角膜曲率、A常数的值域宽泛，可用于各种类型的生理角膜眼和RK术后眼；专用模式适用于近视LASIK术后眼。

Objective To establish a conventional intraocular lens （IOL） calculation formula which is applicable to eyeballs with abnormal data and laser in situ keratomileusis （LASIK） postoperative eyes.MethodsA case-series study was adopted.According to the classical optical theory, a normal IOL implanted eye has the following characteristics： when light is refracted by cornea and arrives on the IOL plane, the value of refractive power （F1） ＋ IOL refractive power （F2） = the value of refractive power which is suitable for vitreous body depth （F3）. Thereafter, a mathematical model was built on the basis of theory, experience, and regression analysis data after IOL implantation surgeries.Furthermore, based on the new LASIK postoperative cornea curvature modified formula, the two kinds of IOL calculation programs of conventional and LASIK postoperative eyes were established.The test data was collected from 644 patients who had undergone the cataract extractions and IOL implantation surgeries （600 physiological cornea eyes, 7 radial keratotomy [RK] eyes and 37 LASIK postoperative eyes） at the Affiliated Drum Tower Hospital of Nanjing University Medical School.Through the analysis of these data, the new formulas were examined. ResultsWith IOL refractive power of 607 eyes （including 7 RK postoperative eyes）, the average error of XLQ formula （the tentative name of the established formula in this study）was 0.1 D, and the 95% limits of agreement range was -1.1 to ＋ 1.2 D. The error range of IOL refractive power predicted by XLQ, SRK-T and Haigis formulas was -2.21 to ＋ 2.25 D, -5.10 to ＋ 5.63 D and -3.00 to ＋ 3.18 D, respectively, the absolute average error of IOL refractive power predicted by the three formulas was （0.43±0.28）, （0.74±0.53） and （0.79±0.49）D, respectively.Compared with SRK-T and Haigis formulas, the average error of IOL refractive power predicted by XLQ formula was Lower, with significant differences between them （both at P=0.000）. The error value of IOL refractive power predicted by XLQ formula had no statistical correlations with axial length （AL）, keratometry （K） and A constant respectively （all at P〉0.05）, while the error value predicted by SRK-T and Haigis formulas had statistical correlations with AL, K and A constant, respectively （all at P〈0.05）. Thirty-seven patients who had conducted LASIK for myopia （and whose IOL refractive power value were predicted by XLQ formula） had been undergone the postoperative examination.Comparing the predicted and actual value, the error range of IOL refractive power was -0.52 to ＋ 1.18 D, and the absolute average error was （0.49±0.26）D.Conclusions The conventional mode of the XLQ formula established in this study can be used in the cases with broad values of axial length, corneal curvature and A constant, as well as various types of physiological cornea and RK postoperative eyes; the dedicated mode is suitable for LASIK postoperative eyes of myopia.