Repeated Red Light Therapy had been used as an amblyopia therapy for children as well as the myopia control in primary schools. However, ultra low lever of red light therapy with irradiance of 0.37mW and 0.60mW effectiveness and safety for 3~ 6 year-old myopia treatment or slow myopia progression are seldom reported.

Repeated Red Light Therapy had been used as an amblyopia therapy for children as well as the myopia control in primary schools. However, ultra low lever of red light therapy with irradiance of 0.37mW and 0.60mW effectiveness and safety for 3~ 6 year-old myopia treatment or slow myopia progression are seldom reported. Here we design this control and random prospective study to find the two types light with different irridance to two ages (3~4 years old and 5~6 years old) respectively. Wether the dose and effectiveness exit or not for 3~6- year- old myopia control.

Inclusion Criteria:

• 3~6 years old;
• Myopia Spherical Equivalence Refraction <=-0.50D;
• Written Informed Consent;

Exclusion Criteria:

• Cannot approval with written informed consent;
• Photophobia or allergy to red light;
• With other severe conditions the principle investigators refused to enroll this study