Andreo L K, Wilson M E, Saunders R A
N. Edgar Miles Center for Pediatric Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston 29425-2236, USA.
J Pediatr Ophthalmol Strabismus. 1997 Jul-Aug;34(4):240-3. doi: 10.3928/0191-3913-19970701-12.
Intraocular lenses (IOLs) are being implanted in children with greater frequency and in a wider age range. The accuracy of available regression and theoretical formulas in predicting correct IOL power for pediatric eyes, however, has not been reported.
We reviewed medical records of 47 consecutive pediatric IOL implantations after cataract extraction that met inclusion criteria. Age at surgery ranged from 2 months to 10 years, with measured axial lengths of the eye between 18.6 and 26.7 mm. For the purpose of this study, the 2-month postoperative refraction was considered the post-IOL refractive outcome. Using preoperative globe axial length, corneal curvature, IOL power, and the A constant for the lens provided by the manufacturer, we employed the four common IOL power formulas (one regression formula [SRK-II] and three theoretical formulas [SRK-T, Holladay, and Hoffer Q]) to predict refractive outcome.
The average difference between predicted and actual postoperative refractive error ranged from 1.2 to 1.4 diopters (D) for all formulas. Predicted postoperative refraction was less than the actual in 89 calculations and greater in 99. No significant differences in predictive accuracy were found in any of the axial length groups (group 1 P = 0.79, group 2 P = 0.42, and group 3 P = 0.86). All formulas were slightly less accurate in group 3 patients (shortest eyes). In this group, the Hoffer Q formula had the lowest error (1.4 D) and the SRK-II had the highest error (1.8 D). The difference was not statistically significant (P = .86).
In our pediatric study eyes, all four IOL power calculation formulas predicted mean refractive outcome within 1.4 D. Theoretical formulas did not outperform the regression formula.
人工晶状体（IOL）在儿童中的植入频率越来越高，且植入年龄范围更广。然而，目前可用的回归公式和理论公式在预测儿童眼睛正确IOL屈光度方面的准确性尚未见报道。
我们回顾了47例连续的白内障摘除术后符合纳入标准的儿童IOL植入的病历。手术年龄从2个月至10岁，测量的眼轴长度在18.6至26.7mm之间。为了本研究的目的，将术后2个月的屈光状态视为IOL植入后的屈光结果。利用术前眼轴长度、角膜曲率、IOL屈光度以及制造商提供的晶状体A常数，我们采用了四种常用的IOL屈光度公式（一种回归公式[SRK-II]和三种理论公式[SRK-T、Holladay和Hoffer Q]）来预测屈光结果。
所有公式预测的术后屈光误差与实际术后屈光误差之间的平均差值在1.2至1.4屈光度（D）之间。在89次计算中，预测的术后屈光小于实际值，在99次计算中大于实际值。在任何眼轴长度组中均未发现预测准确性的显著差异（第1组P = 0.79，第2组P = 0.42，第3组P = 0.86）。所有公式在第3组患者（眼轴最短）中准确性略低。在该组中，Hoffer Q公式的误差最低（1.4D），SRK-II公式的误差最高（1.8D）。差异无统计学意义（P = 0.86）。
在我们的儿童研究眼中，所有四种IOL屈光度计算公式预测的平均屈光结果在1.4D以内。理论公式并不优于回归公式。
