Inclusion Criteria:  Myopia: between -1.00D and 4.00D in both eyes Astigmatism: <1.5D for with-the-rule astigmatism, <1.00D for the against-the-rule astigmatism Visual acuity: the best corrected vision acuity(BCVA)≥20/20 in both eyes Subjects that volunteer to participate in the clinical trial and sign informed consent  Exclusion Criteria:  Contraindications of wearing Ortho-K. Diagnosis of strabismus, amblyopia and other refractive development of the eye or systemic diseases. Any type of strabismus or amblyopia Systemic condition which might affect refractive development (for example, Down syndrome, Marfan's syndrome) Ocular conditions which might affect the refractive error (for example, cataract, ptosis)