Occasional contact lens wear will not have serious effects on the eyes as long as it is worn regularly, for a short period of time, and with attention to personal hygiene. However, because contact lenses directly cover the cornea, they can cause symptoms such as dry eyes, foreign body sensation or tearing, which can be relieved with rest after removing the contact lenses. Long-term contact lens wear or not standardized hygienic wear contact lenses may have the following kinds of hazards: 1, infection: most people take off contact lenses directly after dipping in the care solution, can not completely remove the residual microorganisms on the lens, tear proteins, collagen and other substances, long time deposits are granular, repeated friction caused by giant papillary conjunctivitis, infectious keratitis, etc.; 2, eye resistance decreased: due to long-term contact lens wear, isolated air, can cause corneal hypoxia caused by dry eye, manifested as sore eyes, increased secretions, blurred vision, burning eyes and other symptoms; 3, corneal damage: due to unsuitable contact lens size or poor material, long-term wear corneal can cause serious corneal wear, and even cause epithelial detachment, perforation, seriously affect vision loss. Mild patients can be treated by applying drugs such as levofloxacin, but patients with severe damage may require surgery; 4, eye nerve paralysis: because contact lenses cover the eye for a long time, causing corneal ischemia, hypoxia, may cause nerve endings paralysis, resulting in corneal hypoacusis, and even inflammation can not be detected, thus delaying treatment; 5, other hazards: long-term contact lens wear can also accelerate The corneal aging, deepening myopia, in old age can lead to cataracts. So when wearing contact lenses, we should pay attention to the length of time should not be too long, to develop good wearing habits and health habits to avoid unnecessary damage.