More and more girls are wearing contact lenses for the sake of beauty, but these girls may not know that improper wearing of contact lenses and some incorrect habits can harm their eyes. In our ophthalmology clinic, almost every day there are 5-6 female friends who have corneal infections due to improper contact lens wear, which not only affects their work but also causes vision damage. Recently received such a young girl, Xiaogong myopia 200 degrees, 5 years daily wear annual contact lenses, in recent years changed to wear “contacts”, because of work needs Xiaogong weekly business trips to the field and often overnight wear contact lenses, last Sunday after returning from the business trip immediately appeared to have both eyes red and painful, tearing and can not open their eyes, Monday! On Monday, he came to the ophthalmology department for consultation, and after the ophthalmology department’s slit-lamp microscopic examination and corneal staining, it was found that a grayish-white corneal ulcer foci appeared on the cornea of both eyes of Xiaogong, confirming that Xiaogong suffered from bilateral “bacterial corneal ulcers”. In medicine, contact lenses are known as “corneal contact lenses”, which are made according to the shape of the human cornea, with transparent or dyed materials, directly covering the cornea, in order to achieve vision correction, cosmetic or therapeutic purposes. Contact lenses can overcome the optical shortcomings of frame lenses such as image magnification, reduction and prismatic effect because there is no frame obstruction, bringing a broader field of vision to the wearer. They are aesthetically pleasing, natural and undetectable, bringing comfort and convenience to many refractive error patients. However, even if contact lens lenses are of good quality and high oxygen permeability, they will still hinder the eye’s need for oxygen because the cornea breathes with the air. Contact lenses, after all, are foreign objects placed on the cornea. Every blink of the eye will cause some friction between the contact lenses and the surface of the eye, and at the same time, it covers the surface of the cornea, making it difficult for the cornea to absorb oxygen directly from the air. Therefore, wearing contact lenses for a long period of time, or continuously, will cause the cornea to be in a constant state of hypoxia, which will lead to corneal epithelial edema, erosion, and, in the event that bacteria or viruses are present, may lead to keratitis, or even the formation of corneal inflammation. If bacteria or viruses are present, it may lead to keratitis or even the formation of corneal ulcers. In addition, because of the lack of oxygen supply, the neovascularization of the conjunctiva around the cornea will grow into the transparent cornea, and once the cornea grows neovascularization, its transparency will be affected. Corneal ulcers are a serious complication of contact lens wear, in addition to other common complications such as conjunctival allergic reactions, macropapillary conjunctivitis, superficial punctate keratitis, corneal endothelial changes, and dry eye. Therefore, it is important to wear contact lenses that are healthy, hygienic and disposable. It is also important to emphasize that the contact lens prescription is not based on computerized optometry data alone, and it is recommended that a standardized medical optometry be conducted to accurately match the prescription, as I have encountered more contact lens wearers with myopic friends wearing contact lenses with high prescription, which results in fatigue and other discomforts.