External Validation of a Model to Predict Postoperative Globe Axial Length in Children After Bilateral Cataract Surgery

PURPOSE To perform the external validation of a model to predict postoperative axial length (AL) in children undergoing bilateral cataract surgery with primary intraocular lens (IOL) implantation older than 2 years. DESIGN Validation study using a retrospective case series METHODS Using a different population than the one that created the model, but with the same characteristics regarding age, bilateral cataract, primary IOL implantation, and follow-up assessment, AL was estimated. The AL values ​​estimated by the model were compared with the AL measured in the follow-ups. RESULTS Fifty-five eyes of 30 children were selected for this study; in five children with bilateral cataracts, only one eye was included. The median age at the time of surgery was 5.01 years. Follow-up AL measurements were obtained for 179 visits. The median age at the final follow-up visit was 10.15 years. The median AL measured and estimated by the model in all visits were 22.37 mm and 22.16 mm respectively (Person's coefficient: 0.9534; Lin's correlation: 0.9258). In the Bland-Altman analysis, the 95% limit of agreement between the two methods (measured and estimated AL) was 0.71 to -1.19. In three eyes (1.68%) with AL shorter than 21.2 mm, the difference was >0.71, and in nine eyes with AL longer than 22.5 (5.03%), it was less than -1.19. The Median AL measured and estimated at the final visit were 22.69mm and 22.43mm, respectively. CONCLUSION Our previously developed prediction model for globe AL growth demonstrated good external validity by accurately predicting measured AL changes with growth in the validation cohort.