Efficacy and Rebound Effects of Repeated Low‐Level Red Light versus High‐Concentration Atropine for Myopia Control in Children: A Randomized Controlled Trial

BACKGROUND: To compare the efficacy of repeated low-level red light (RLRL) and high-concentration atropine (HCA, 1%) in myopia control and evaluate rebound effects after cessation. METHODS: In this 15-month, prospective, single-blinded randomized controlled trial, 136 myopic children (6-12 years) were randomly assigned to RLRL or HCA (1:1). Treatment lasted 12 months followed by a 3-month washout. Outcomes included change in axial length (AL), spherical equivalent refraction (SER), subfoveal choroidal thickness (SFChT), and safety. RESULTS: A total of 116 children completed ≥ 1 follow-up (RLRL: 65, HCA: 51). At 12 months, RLRL showed superior efficacy: AL regressed by -0.014 mm (95% CI: -0.067 to 0.039) versus a 0.094 mm increase with HCA (95% CI: 0.046-0.141; p = 0.005). SER decreased by 0.24 D (95% CI: 0.093-0.387) in RLRL and increased by 0.035 D (95% CI: -0.154 to 0.083) in HCA (p = 0.008), while SFChT increased by 26.000 μm (95% CI: 18.082-33.918) and 12.761 μm (95% CI: 3.867-21.655; p = 0.032), respectively. During the 3-month washout, AL elongation was slightly greater in RLRL (0.163 mm) compared to HCA (0.115 mm; p = 0.014). Higher compliance (≥ 75%) with RLRL correlated with better 12-month efficacy (AL: -0.064 mm vs. 0.084 mm; p = 0.011) but worse rebound (AL: 0.183 mm vs. 0.122 mm; p = 0.02). No severe adverse events were reported. CONCLUSIONS: RLRL exhibited superior 12-month efficacy over HCA (1%) but was associated with slightly higher rebound. Optimizing RLRL regimens, including implementing reduced dosing and tapered withdrawal, could sustain benefits while limiting rebound. TRIAL REGISTRATION: Chinese Clinical Trial Registry: ChiCTR2100051940.