Effect of Low-Dose Atropine on Choroidal and Anterior Scleral Thickness in Myopic Egyptian Children: A Randomized Controlled Trial

Purpose This study aimed to evaluate the short-term effect of low-dose atropine eye drops on subfoveal choroidal thickness (SFCT), anterior scleral thickness, and other ocular biometric parameters in myopic children.Methods This prospective, randomized controlled trial included 92 myopic children aged 6–12 years. Participants were randomly assigned in a 1:1:1 ratio to receive 0.05% atropine, 0.01% atropine, or placebo eye drops nightly for 16 weeks. Only one eye (the right eye if both were eligible) was included per participant to avoid inter-eye correlation bias. Comprehensive ophthalmic examination was performed at baseline and at 4, 8, 12, and 16 weeks. SFCT and anterior scleral thickness were measured using spectral-domain optical coherence tomography (OCT). Axial length (AL), intraocular pressure (IOP), anterior chamber depth (ACD), and central corneal thickness (CCT) were also evaluated. Changes over time and between groups were analyzed using repeated-measures analysis. The trial was registered at ClinicalTrials.gov (NCT06265454).Results Over the follow-up period, SFCT increased significantly in both treatment groups: from 350.21 ± 51.46 μm to 391.42 ± 48.41 μm in the 0.01% group (p = 0.025), and from 319.45 ± 89.28 μm to 396.48 ± 89.64 μm in the 0.05% group (p = 0.021). In contrast, SFCT decreased in the placebo group, from 389.55 ± 62.34 μm to 354.78 ± 50.99 μm (p = 0.117). Between-group analysis demonstrated significantly greater increases in the rate of SFCT change in both atropine groups than in the placebo group throughout follow-up. Although no significant within-group changes in axial length were observed, both atropine groups exhibited significantly lower rates of axial elongation than the placebo group. Anterior scleral thickness, CCT, ACD, and IOP remained stable across all study groups (p > 0.05).Conclusion Both low-dose atropine concentrations resulted in short-term choroidal thickening in Egyptian myopic children, with a stronger response in the 0.05% group. No significant changes were observed in anterior segment parameters or intraocular pressure. These findings support a concentration-dependent choroidal mechanism in myopia control.