Both are good, it depends on personal preference. I think Erchen is better. Because Alxing is specially developed to protect the vision of teenagers aged 3-16 years old. There are many years of clinical trials and use cases. It can be said that as long as you insist on using Alxing in conjunction with it, there will be no ineffective results. The Alxing photometer has its own patent certificate, which uses the principle of light to prevent and control children's myopia. There is a kind of red light in the sun that can promote the circulation of the epiretinal membrane, and the Alxing uses the principle of light. This kind of red light is emitted at a low frequency and intensity to promote the circulation of the epiretinal epithelium of the eye, improve scleral hypoxia, thereby preventing and controlling children's myopia and controlling the growth of the axial length of the eye.