What is the relationship and difference between orthokeratology and contact lenses sold in optician shops? & nbsp. ① Different materials: The contact lens is silicon hydrogel. The shaping mirror is a material with high oxygen permeability and strong biocompatibility, which belongs to the special material for medical devices that can be implanted into the human body. & nbsp. ②Different sizes: contact lenses have a large diameter and completely cover and cover the entire “black eyeball”, which can easily lead to corneal hypoxia; plastic lenses only cover 90% of the cornea, ensuring safe and healthy eyes. ③The authority is different: contact lenses are ordinary goods, which can be purchased freely in shopping malls, supermarkets and even online; keratoplasty are three types of medical devices that are strictly and uniformly managed by the Ministry of Health. Only the above professional ophthalmologists are qualified for fitting. & nbsp.④ The design is different: the invisible eye is a single arc, which is completely adhered to the corneal surface after wearing, and will absorb the nutrient solution in the eye, causing symptoms such as red eyes, dry eyes, even corneal inflammation, ulcers, etc. In addition, due to contact lenses Direct contact with the cornea, as the eyeball rotates, the lens will rub against the cornea, which is harmful to the cornea. The orthopaedic mirror is designed with extremely precise 3 to 6 arc inverse geometry. There is a 10-15um tear layer between the lens and the cornea. There is no contact with the cornea and no trauma. The exchange of tear fluid ensures eye health. ⑤Different functions: Invisible eyes can only replace the frame to achieve the purpose of seeing clearly; the shaping lens achieves clear vision without wearing glasses during the day through multi-curve defocusing, the most important thing is to control the growth of myopia , To further avoid the health damage caused by the increase in degrees. & nbsp. ⑥The scope of application is different: contact lenses are not suitable for use or recommended for children or adolescents under the age of 18; the safety and effectiveness of orthokeratology lenses have passed the review and certification of the World Health Organization, the National Health and Health Commission, and the Food and Drug Administration, Dedicated to the control of myopia in children and adolescents.