1, conjunctiva: giant papillary conjunctivitis; keratoconjunctivitis; 2, cornea: corneal infection and ulceration; corneal edge neovascularization; decreased corneal sensitivity, radius of curvature has changed; 3, acute corneal hypoxia syndrome: mainly acute corneal hypoxia, corneal edge anemia ring, peripheral ulceration, corneal edema, vision loss; 4, extensive corneal abrasions, epithelial detachment; 5, other: visual fatigue syndrome, dry eye , ptosis, etc. Prevention methods: 1. go to the hospital before wearing contact lenses to check whether they are suitable for wearing; as well as wearing under the guidance of medical professionals; 2. advocate daily wear lenses, daily wear duration should not be too long, should not wear lenses overnight; 3. strict disinfection, as well as wearing hands to keep clean; 4. if discomfort, please seek medical advice in a timely manner to avoid delays; 5. disinfectant and corneal contact lens production choose the regular manufacturers.