Accuracy of intraocular lens power calculation in pediatric cataract surgery

Abstract

Objective To determine the accuracy of intraocular lens (IOL) power calculation in a group of pseudophakic children. Methods A relrospective analysis of biometric and refractive data was performed on 62 eyes of 37 infants and children, who successfully underwent cataract extraction and IOL implantation. SRKII were used to calculate the IOL power. The postoperative refractive outcome was taken as the spherical equivalent of the refraction at 2 months afier 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 (SD 1.66), 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 =.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. Key words: Cataract; Congenital; IOL power calculation; Prediction error