Orthokeratology in Children with Myopia and Intermittent Exotropia: the Nanjing Strabismus Cohort

AIM: To assess the impact of orthokeratology on myopia progression, exotropia conditions and visual function in children with myopia and intermittent exotropia. METHODS: This prospective cohort study recruited children aged 8-13 years with myopia and intermittent exotropia who chose to wear either orthokeratology lenses or single-vision spectacles. Participants underwent ocular assessments every 3 months over 1 year. Generalized estimating equations was employed to account for inter-eye correlation. RESULTS: Orthokeratology group had slower axial elongation than single-vision spectacle group at 1 year (0.24 mm vs. 0.40 mm; difference = -0.17, 95% CI: -0.25, -0.09; P < 0.001). In the orthokeratology vs. spectacle group, respectively, the mean change was -5.03 prism diopters (PD) vs. 1.77 PD (difference = -6.81, 95% CI: -9.38, -4.23; P < 0.001) in distant exodeviation, -4.11 PD vs. 0.39 PD (difference = -4.50, 95% CI: -8.28, -0.72; P = 0.02) in near exodeviation, -0.28 vs. 0.22 (difference = -0.49, 95% CI: -1.00, 0.02; P = 0.06) in distant exotropia control, and -0.25 vs. 0.26 (difference = -0.51, 95% CI: -0.98, -0.05; P = 0.03) in near exotropia control at 1 year. Improved accommodative functions were observed in the orthokeratology group at 1 year, including monocular accommodative facility (P = 0.004), negative relative accommodation (P = 0.02), and positive relative accommodation (P = 0.02). No serious adverse effect was observed throughout the follow-up period. CONCLUSION: In children with myopia and intermittent exotropia, orthokeratology may be recommended for its efficacy in controlling myopia progression, and for its potential to improve or maintain exotropia conditions.