Differences in Posterior Ocular Morphology Following Red Light Therapy Versus 0.01% Atropine for Myopia Control: A Randomized Controlled Trial Analysis.

PURPOSE: The purpose of this study was to compare longitudinal changes in three-dimensional (3D) macular morphology between repeated low-level red-light (RLRL) therapy and 0.01% low-dose atropine (LDA) treatment in myopic children.

METHODS

This secondary analysis of a randomized controlled trial (RCT) included 50 myopic children (aged 7-15 years) randomized to receive either RLRL therapy (650 ± 10 nm) or 0.01% atropine eye drops. Spectral-domain optical coherence tomography (OCT) was performed at baseline and 1, 3, 6, and 12 months. Custom software was used to perform distortion correction and quantify macular curvature (MC; mm-1), macular outward scleral height (MOSH; µm), and their respective asymmetry indices. Primary outcomes were 12-month changes in average regional macular curvature. Secondary outcomes included changes in MOSH, asymmetry indices, and retinal layer thicknesses. Linear mixed-effects models analyzed longitudinal changes.

RESULTS

At 12 months, RLRL showed greater macular flattening than 0.01% atropine across all regions (mean differences, × 10-3 mm-1): central (9.0, 95% confidence interval [CI] = 4.4-13.6, P < 0.01), temporal (9.7, 95% CI = 6.7-12.8, P < 0.001), inferior (8.4, 95% CI = 5.2-11.6, P < 0.001), superior (7.0, 95% CI = 4.0-9.9, P < 0.001), and nasal (3.7, 95% CI = 0.8-6.7, P < 0.05). The inter-group difference was most pronounced centrally and decreased with eccentricity. MOSH decreased superiorly and increased inferiorly in the RLRL group at 12 months, whereas the LDA group showed minimal change. Both nasal-temporal and superior-inferior macular curvature asymmetry indices increased significantly more in the RLRL group (P < 0.001 and P < 0.05, respectively). No inter-group differences in retinal layer thickness changes were observed.

CONCLUSIONS

Over 12 months, RLRL showed broader macular flattening and more region-specific MOSH changes compared with 0.01% atropine in this cohort. However, the underlying mechanisms and the independent contribution of myopic progression to these morphological differences require further study.