Abstract:AIM: To investigate the effects of cataract surgery on the axial length/corneal radius (AL/CR) ratio and choroidal thickness (CT) in school-age children and to analyze the underlying mechanisms. METHODS: This prospective cohort study enrolled school-age children who underwent phacoemulsification with intraocular lens (IOL) implantation between September 2024 and February 2025. The right eyes of bilateral cases and the affected eyes of unilateral cases were classified as Group A. Within this group, eyes implanted with trifocal IOLs were designated as Subgroup A1, whereas those receiving monofocal IOLs were designated as Subgroup A2. The contralateral healthy eyes of the unilateral cases formed Group B. Axial length (AL) and corneal curvature were measured using the IOL Master 700. CT was assessed using swept-source optical coherence tomography. RESULTS: A total of 50 eyes from 32 patients (Subgroup A1, n=21, 8.38±2.36y; Subgroup A2, n=11, 7.55±2.16y; Group B, n=18, 8.22±2.44y) were included in the study. Preoperatively, AL was markedly shorter in Group A compared to Group B (P<0.05), but there was no notable difference in the AL/CR ratio (P=0.144). During the follow-up period, neither the AL/CR ratio nor CT demonstrated any notable changes within Group A (all P>0.05). Conversely, Group B showed a considerable increase in the AL/CR ratio and a pronounced reduction in CT, both statistically significant (all P<0.05). No notable differences were observed between Subgroups A1 and A2 in any of the measured parameters. Correlation analysis revealed meaningful negative correlations between AL, AL/CR ratio, and central subfield choroidal thickness (CSCT) in Group A at 1mo postoperatively and at the final follow-up (P<0.05). Still, no correlation was found among the changes in these parameters over the follow-up period. CONCLUSION: In the early postoperative period, operated eyes of school-aged children show a stable AL/CR ratio and CT. Although a stable structural negative correlation between these two parameters is observed in operated eyes, the longitudinal coordinated relationship is disrupted, which may be related to the loss of accommodative function. Longer-term follow-up is needed to corroborate these findings.