With the rapid development of digital imaging technology, the exposure and dependence of children and adolescents on these products are increasing day by day, coupled with the heavy burden of schoolwork, the age of myopia is getting younger and the prevalence is increasing year by year. Over the years, clinical practice at home and abroad has proven that keratoplasty can correct myopia while controlling its development and is safe and effective, so it is a recommended method. I. Lens care: The daily care of lenses is an important aspect to ensure the safety and eye health of wearing lenses. If the lenses are broken, contamination will greatly increase the chances of eye surface infection, leading to irreversible adverse consequences in serious cases. (a), storage of lenses: 1. Routine storage: for children who wear lenses routinely every day After use, the lenses should be cleaned and disinfected with the care solution within the expiration date and put in the duplex box, the care solution in the duplex box must be changed daily, the care solution should reach two-thirds of the box, completely submerge the lenses and soak them for 4 to 6 hours before wearing them. Many children and parents who wear glasses throw the used lenses directly into the old care solution of the previous day and clean the lenses only on the night of the wearing day, before wearing them, which is a very serious mistake that increases the chances of inflammation of the eye surface. 2. Special preservation: for children who wear lenses unconventionally (1) No lenses for a week: clean the lenses and put them in a duplex box, changing the care solution every 2 days. (2) Not wearing lenses for more than a week: dry lenses are kept. (B) cleaning of lenses: 1. hand cleaning: six-step washing technique: inside, outside, clip, bow, large, stand (end) 2. lens cleaning technique: place the lens in the palm, drop 3-5 drops of multifunctional care solution, radial cleaning from the center of the lens to the outside with the belly of the index finger or ring finger, cleaning the lens side first, about 10 in each direction, depending on the degree of dirtiness of the lens. Then turn the lens with the belly of the finger and clean the other side in the same way. 3. Place the cleaned lenses in a duplex box with cleaning solution for 4 to 6 hours. 4. Every week or two weeks, the lenses are de-proteinized. (c), care products: care products use notes Boshion Soothing Solution moisten the lens and cornea use when wearing and removing the lens open shelf life of 3 months Menicare Plus multifunctional care solution lens cleaning, disinfection, rinsing open shelf life of 3 months Boshion New Clean Care Solution lens cleaning, disinfection, rinsing open shelf life of 3 months Menicon Progen strong deproteinization Protein solution weekly removal of deposits such as protein on the surface of the lens, deep sterilization and cleaning shelf life see box Do not get into the eyes or contact with clothing Bosidon Enzyme weekly removal of deposits such as protein on the surface of the lens, deep sterilization and cleaning shelf life of 25 weeks after opening Do not get into the eyes Bosidon Advanced weekly removal of deposits such as protein on the surface of the lens, deep sterilization and cleaning shelf life of 3 months after opening Do not get into the eyes (d) Precautions: 1, Care products must be used within the expiration date 2, care products in strict accordance with the instructions, care procedures can not be reversed 3, keep the bottle clean, open the bottle and place the cap upwards, close the bottle in time after use 4, lenses, care solution, suction stick, mirror box and other related items to be placed at room temperature, away from light, dry environment storage 5, prohibit the use of expired or physical characteristics of the change of care products, care products please in 6, care products are prohibited to be used repeatedly II, lens replacement: (a), the lens material and physical properties 1, oxygen permeability: because most of the corneal plastic lens night wear, so the choice of material DK value should be greater than 90. 2, elastic modulus: elastic modulus is very critical to the effectiveness of shaping, refers to the ability of the material to resist deformation, with the extension of wearing time, easy to be rigid corneal plasticity. The plasticity of the lens, so the life of the keratoplasty lens is generally not more than 2 years. (b), lens care, replacement and corneal infection The current incidence of corneal infection associated with keratoconus is 7.7 per 10,000, and the time from lens wear to serious infection ranges from 3 months to 10 years, with an average of 2.7 years. The main reasons for serious infections are: unskilled operation at the beginning of the wearing period, slackening of safety awareness in the middle and end of the wearing period, no longer adhering to regular follow-ups, and cutting corners on operational steps, such as no longer strictly cleaning the lenses and cases. Overuse of lenses and failure to replace them with new lenses in a timely manner. If these patients are seen in time when discomfort occurs, their vision recovers well after treatment and no serious visual impairment occurs. The maximum life span of OK lenses is 2 years, and the clinically recommended replacement cycle is 1~1.5 years. If the lenses are overused, the indexes of the lenses will decrease, and the surface wear will be significant, which will easily lead to corneal infection if no attention is paid to hygiene. [Case] A boy suffered from keratitis in both eyes due to overuse of the lenses and lack of cleaning for 1 week. A 12-year-old boy, Mingming, went to Shanghai 10th People’s Hospital in 2012 to be fitted with OK lenses, when he had myopia -3.50DS in his right eye and -4.00DS in his left eye. After the doctor informed the child’s parents that the lenses needed to be replaced, the patient and parents did not come to the hospital to replace the lenses at the appointed time and did not come to the hospital for a follow-up appointment from then on. During a phone conversation, the parents said that wearing the lenses was too much trouble and that the child did not have time, and that they wanted to stop wearing the OK lenses. One afternoon in the third year of lens prescription, the child reappeared, complaining of eye redness and eye pain for 3 days, and asking about the medical history revealed that: 1. the lenses were overused for 1 year (3 years of wear); 2. the care solution had been used up 1 week ago, but the parents did not have time to buy new care solution, and the lenses were still wearing lenses ☠ although the lens cleaning had not been done for 1 week. Eye examination: visual acuity: right eye: 0.6, left eye: 0.5, mixed conjunctival congestion, a small infiltrative foci were visible in both corneas with stromal edema below. Lens examination: the lens was markedly scratched, with punctate protein deposits in the basal arc area and significant protein deposits in the reversed arc area of the lens. There were multiple small nicks on the edge of the lens. After two weeks of treatment, the lesions healed and the vision recovered well. Although no serious adverse consequences occurred in the case of Mingming’s child, it was a wake-up call for our doctors and patients. The rope is broken at the fine point and the accident is at the loose point. The prerequisite for safe and effective lens wear is standardized lens care, regular outpatient follow-up and regular lens replacement. Doctors and parents should work together to strengthen safety awareness, eliminate unregulated practices and behaviors, eliminate safety hazards, and ensure safe and effective wear for children.