If contact lenses go on and if the eyes water and sting, it is often because there may be some damage to the corneal epithelium. Contact lens contact with the cornea exacerbates this reaction, which in turn can cause an increased foreign body sensation in the eye, leading to tearing and stinging. This is especially true when wearing soft contact lenses, which can cause oxygen and water deprivation due to the larger size of the contact lens. If once there is damage to the corneal epithelium, this sensation will be aggravated. Therefore, if this situation occurs, we must stop wearing contact lenses in time, and drops of anti-inflammatory drugs and nutritive corneal drugs to promote the healing of the corneal epithelium, usually in 2-3 days the corneal epithelium can be completely healed, and after the complete healing of the corneal epithelium can be appropriate to wear contact lenses again in 1 week.