In this 12-month, multicenter randomized controlled trial, children with high myopia received either repeated low-level red-light (RLRL) therapy with single vision spectacles or single vision spectacles alone. The RLRL group demonstrated significant axial length shortening, a reduction in myopic progression, and increases in choroidal and retinal thickness, indicating that RLRL therapy is a safe and effective method for inhibiting myopia progression in children with high myopia.