研究目的:
                        
                            To evaluate the efficacy and safety of 650nm low-level red-light irradiation for myopia        control and prevention in children under less restrictive conditions than randomized        controlled trials. Participants included children(aged 7 to 18 years, spherical equivalent        error of 0.5D or below) who are already myopic at recruitment, and those who are of        Emmetropia or low hyperopia.