Comparing Myopia Control Efficacy in Children With 4 Methods: Orthokeratology, DIMS, DISK, and SVS.

The goal of this clinical trial is to learn if 3 optical interventions（DIMS, DISC and orthokeratology) to control myopia have different efficacy to slow myopia progression in children when the control is single focus spectacles(SVS). It will also learn about the safety of all 4 interventions. The main questions it aims to answer are: Does orthokeratology slows the progressing myopia more significant than the DIMS or DISK? What medical problems do participants have when taking orthokeratology, DIMS and DISK? Researchers will compare all the 3 interventions to a placebo (SVS) to see if 3 interventions has significant difference in slow the axial length elongation as well as the refraction changes. Participants will: Take orthokeratology, DIMS, DISK or SVS every day for 12 months Visit the clinic once every 3 months for checkups and tests.