Secondary intraocular lens (IOL) implantation is a common treatment for pediatric aphakia. The accurate prediction of IOL power calculation plays a pivotal role in the postoperative development and improvement of visual function for pediatric secondary IOL implantation. Current IOL power calculation formulas were developed based on data from adult phakic eyes and displayed good performance in adult population. However, the formulas showed poor performance in pediatric aphakic population due to the following reasons: 1) In these pediatric aphakic patients, the unavailability of phakic anterior chamber depth (the distance from corneal epithelium to the anterior surface of the lens) and lens thickness (LT) greatly limits the application of some IOL power calculation formulas. 2) IOL power calculation formulas predict the effective lens position on the basis of in-the-bag IOL implantation, whereas sulcus implantation is more widely used in pediatric secondary implantation. Effective lens position in capsular placement is more posterior to ciliary sulcus IOL placement. When applying the initial IOL power calculated for capsular implantation to sulcus implantation, it can lead to refractive errors. 3) Adult eyes have completed their development, with target refractions often being emmetropic or myopic (-3.00 ~ +1.00 D), while pediatric eyes are still developing, necessitating the calculation of an appropriate hyperopic (+0.50 ~ +12.00 D) target refraction to accommodate refractive changes due to ocular growth.To achieve the predetermined target refractive outcomes, the selection and optimization of IOL power calculation formulas is critically important for pediatric secondary IOL implantation.