PURPOSE Calculating the power of a secondary intraocular lens (IOL) requires axial lengths and keratometry measurements. In children, these measurements often need to be done under either sedation at the time of surgery or additional sedation. We devised a method of calculating IOL power using only the aphakic refraction and a standard keratometry value. PATIENTS AND METHODS This retrospective study included children undergoing a secondary IOL procedure who had IOL calculations based on either a measured axial length and a measured keratometry value (with sedation if needed) or a calculated axial length and a standard keratometry value. Comparison of predicted postoperative refraction with actual postoperative refraction was used to evaluate each method. RESULTS The mean difference between predicted and actual postoperative refractions was 2.34 D for the group with actual measurements and 2.50 D for the group with the calculated value method. CONCLUSION The use of the aphakic refraction to calculate axial length and a standard keratometry value provides an alternative for secondary IOL calculations in pediatric patients when ultrasonic or nonsedated ultrasonic axial length measurements are not an option.