Shenzhen Aierxing Service Center mainly provides free expert consultation on myopia prevention and control for children, and its services are quite complete. This is the Elson optical feeder rented by my daughter, and the effect is good. Experts tell us that this instrument is based on the principle of "supplementing light nutrition for eyes". By providing light waves with specific wavelengths to irradiate the retina, it can supplement sunlight and improve vision. As long as you insist on uninterrupted use, you can see the effect in 3 months. If it is invalid, it supports refund, which is quite humanized. You can try it for the children.