Named for their thin, transparent and hard-to-detect nature, contact lenses have become fashionable for today’s teenagers. However, contact lenses are not suitable for all people who need them. Who should not wear contact lenses? 1, primary and secondary school students: primary and secondary school students are in a period of rapid growth and development, eye vision axis has not been shaped, self-care awareness and self-care ability is poor. Contact lenses need to be cleaned and disinfected every day, the procedure is also more tedious, not easy to adhere to. Primary and secondary school students who wear contact lenses too early or for a long time continuously, easy to produce corneal hypoxia and physiological metabolic disorders and other side effects; lens cleaning and disinfection is not strict, will be secondary to infection; lens curvature if not compatible with the cornea, but also cause corneal wear, epithelial shedding, serious cases will lead to corneal ulceration or perforation. 2, cold patients: cold patients often have a lot of germs on their hands, they are easy to take, wear contact lenses into the eyes. In addition, the cold is often accompanied by mild inflammation of the retina, wearing contact lenses will make the inflammation worse. Many cold, cough and pain medications contain ingredients that inhibit tears. Reduced tear production will make contact lenses too dry and less transparent, which in turn affects vision. 3, allergy patients: people with allergies wearing contact lenses are prone to complications such as mild inflammation, eye itching, redness, conjunctivitis and eye swelling. If these conditions are left untreated for a long time, they will likely endanger vision. If allergy sufferers must wear contact lenses, it is best to use them only during the day and to suspend their use at least one day a week. If inflammation occurs, it is best to stop using them. If the inflammation is not reduced after 2 to 3 days, you should go to the hospital immediately. 4, glaucoma, chronic dacryocystitis, conjunctivitis, corneal ulcers, hyperthyroidism and other diseases patients. 5, if already equipped with contact lenses, and the eye is in the inflammation period, to wait until the inflammation disappears before wearing. 6, fever patients: fever when the eye local resistance is reduced, tear secretion is reduced, Bacillus cereus will multiply, so that the metabolites of bacteria deposited between the cornea and the lens, resulting in contact lens oxygen permeability is reduced, the normal metabolism of the cornea is disturbed, thus causing bacterial corneal ulcers. 7, cycling long-distance travelers: long distance cycling, air convection accelerated, so that the soft contact lens moisture reduction, the lens gradually dry hard, eyes will feel discomfort, time: a long time, hardened lenses will damage the cornea, causing eye pain or bacterial infection. 8, middle-aged and elderly: people to 40 years old, the eye tissue will occur more obvious degenerative changes. The local resistance of the eye decreases, especially the ability of the eye to tolerate hypoxia decreases, at this time, if you wear a thin layer of lenses on the surface of the eye, will lead to lack of oxygen to the eye, thus prone to corneal infections, ulcers and other complications. 40 to 60 years old middle-aged people can wear contact lenses for a short period of time, more than 60 years old, it is best not to wear contact lenses, otherwise it is easy to cause serious complications, resulting in permanent vision damage. 9, menstruating women: because women during menstruation and menstruation will come to the first few days, eye pressure is often higher than usual, the eye around the more likely to congestion, especially women with dysmenorrhea more so, when wearing contact lenses, will have a negative impact on the eye. 10, pregnant women: hormonal changes in women during pregnancy, so that the water content of the body also changed, some swelling of the eyelids, corneal thickening, especially in the last three months of pregnancy, because the corneal water, thickening more obvious, will not match the normal optional contact lens lenses, thus causing eye discomfort. Pregnant women with oedema of pregnancy should especially not wear contact lenses.