Research Summary

Low-Dose Atropine Stabilizes Choroidal Thickness Over 2 Years in Children with Myopia

Edited by:
Kate Young

Key Highlights

  • In the MOSAIC randomized clinical trial, 0.01% atropine preserved macular choroidal thickness, while placebo-treated children demonstrated progressive thinning.
  • Choroidal thickening correlated with slower axial elongation and reduced myopic progression across both treatment groups.
  • Mediation analysis showed atropine exerted both direct and indirect effects on choroidal thickness.

In a new analysis from the Myopia Outcome Study of Atropine in Children (MOSAIC), published in Acta Ophthalmologica, investigators found that nightly 0.01% atropine eye drops stabilized macular choroidal thickness over a 2-year period compared with placebo. Choroidal thinning has been associated with myopic progression and risk of myopic maculopathy, making these findings clinically relevant for ophthalmologists managing pediatric myopia.

For their study, researchers conducted a 3-year, randomized, double-masked, placebo-controlled clinical trial in Dublin, Ireland. The present analysis included 187 children with myopia aged 6–16 years with complete 2-year data (126 atropine; 61 placebo). Participants were randomized 2:1 to 0.01% atropine or placebo and used drops nightly for 24 months. Choroidal thickness was measured with swept-source OCT (Topcon Triton) after cycloplegia, using standardized imaging times and segmentation protocols. Linear mixed models evaluated longitudinal changes, while mediation analyses assessed direct and indirect atropine effects through axial length (AL) and spherical equivalent refraction (SER).

Study Findings

At 2 years, children treated with atropine maintained stable subfoveal ChT (0.49 ± 2.22 μm), whereas the placebo group demonstrated progressive thinning (−9.46 ± 2.69 μm; P = .034). Similar patterns were seen across parafoveal and perifoveal regions, with significant treatment differences at 24 months across all macular subfields. Children with slower axial elongation or slower myopic progression exhibited choroidal thickening regardless of treatment arm, while fast progressors showed thinning. ChT changes were negatively correlated with AL elongation (r = −0.33) and positively correlated with SER changes (r = 0.28). Mediation analysis indicated atropine’s effects on ChT were predominantly direct (68.3% for AL pathway; 80% for SER pathway).

Subgroup analyses revealed larger treatment effects in children less impacted by COVID-19 lockdown measures, paralleling previously reported differences in myopia control outcomes.

Clinical Implications

The authors note that stabilizing choroidal thickness may be clinically meaningful, as thinning is an established risk factor for myopic maculopathy. The study also highlights that the atropine effect on ChT is not fully explained by AL or SER changes, suggesting a direct pharmacologic action on the choroid. No safety concerns related to choroidal changes were reported.

Limitations included uncontrolled lifestyle factors such as exercise and caffeine intake, though these were unlikely to differ between masked treatment groups.

Expert Commentary

“Children treated with 0.01% atropine displayed stable choroidal thickness over the study period, while placebo-treated participants showed progressive thinning. As choroidal thinning is associated with diseases such as myopic maculopathy, these findings suggest that atropine’s effect on the choroid, along with its impact on slowing axial eye growth, may help mitigate future disease risk,” the researchers concluded.

Reference
Kobia-Acquah E, Lingham G, Flitcroft DI, Loughman J. Two-year changes of macular choroidal thickness in response to 0.01% atropine eye drops: Results from the MOSAIC clinical trial. Acta Ophthalmol. 2025;103:984–997. doi:10.1111/aos.17429.