儿童白内障手术人工晶状体度数计算准确性分析

Accuracy of intraocular lens power calculation in pediatric cataract surgery

目的分析儿童眼人工晶状体度数计算的准确性。方法回顾性研究37例（62只眼）行先天性白内障摘除加人工晶状体（IOL，intraoeular lens）植入术患儿生物测量及屈光状态数据，应用SRKI／计算IOL度数。术后2个月行视网膜检影验光检测屈光状态。分析手术年龄，眼轴长度，IOL植入时机与IOL度数计算准确性关系。结果全部平均绝对预测误差为（1．56±1．43）D。绝对预测误差低于1．0D共32只眼，占总眼数52％。眼轴≤20mm组绝对预测误差为（2．75±1．66）D，〉20mm组为（1．06±0．93）D，2组间差异具有统计学意义（P〈0．01）。年龄≤2岁组绝对预测误差为（2．38±1．65）D，〉2岁为（1．04．4-0．99）D，2组间差别具有统计学意义（P〈0．01）。I期IOL植入组绝对预测误差为（1．37±1．35）D，II期IOL植人为（2．03±1．56）D，2组间差异无统计学意义（P=0．22）。结论全组植人的IOL度数安全有效。眼轴≤20mm及年龄≤2岁患儿绝对预测误差明显增加。该研究证明，专门为儿童眼设计IOL计算公式是有必要的。

Objective To determine the accuracy of intraocular lens （IOL） power calculation in a group of pseudophakic children. Methods A retrospective analysis of biometric and refractive data was performed on 62 eyes of 37 infants and children, who successfully underwent cataract extraction and IOL implantation. SRK II were used to calculate the IOL power. The postoperative refractive outcome was taken as the spherical equivalent of the refraction at 2 months after surgery by retinoscopy. The data were analyzed to assess the effects of age at the time of surgery, axial length, and primary or secondary intraocular lens implantation on the accuracy of calculation of IOL power. Results For the overall group the mean and median prediction errors were 1.56D （SD 1.43）. There were 32 eyes＇ absolute predictions errors lower than 1D （52%）. The mean absolute prediction errors in eyes with axial lengths ≤20 mm were 2.75 D （SD1.66）, and in eyes 〉20 mm were 1.06 D （SD 0.93）. The mean absolute prediction errors in eyes in children aged ≤2 years were 2.38 D （SD 1.65）, and in children aged 〉2 years were 1.04D （SD 0.99）. The differences between the absolute prediction errors for both axial length and age were statistically significant （P 〈0.01）. The mean absolute prediction errors in eyes with primary IOL implantation were 1.37D （SD 1.35）, and secondary intraocular lens implantation were 2.03D （SD 1.56）. The differences between the absolute prediction errors primary or secondary intraocular lens implantation, were not statistically significant （P =0.22）. Conclusions For the overall group IOL power calculation is generally acceptable. In eyes with axial lengths less than 20 mm and in children younger than 2 years of age larger errors can arise, and the variations increase. This study demonstrates the need for an IOL formula specifically designed for pediatric use.