Sore eyes when wearing contact lenses may be a normal phenomenon caused by inappropriate contact lenses, or it may be caused by diseases such as keratitis, conjunctivitis, and other diseases such as dry eye. 1. Inappropriate contact lenses: When patients wear contact lenses and experience sore eyes, it is considered that the contact lenses worn by the patient are inappropriate, which is a normal phenomenon and will be relieved if the lenses are removed. 2. Keratitis: Keratitis is mostly caused by bacterial, viral and other pathogen infections or the patient’s own disease when the defense ability is weakened. The patient will have eye pain, photophobia, eyelid spasm, etc., and there will also be tearing, vision loss, visual impairment and other symptoms. 3. Conjunctivitis: Conjunctivitis has many causes, including bacterial and immunologic lesions. The main symptoms of patients are dry eyes, redness, pain, itchy eyes, etc., and there will also be foreign body sensation, photophobia, increased secretion and other symptoms. 4. Other: Dry eye, glaucoma and other diseases can also cause patients to have sore eyes when wearing contact lenses. When patients experience sore eyes while wearing contact lenses, they do not need to be treated if the symptoms are caused by contact lenses. If it is caused by a disease, the patient should seek medical attention and follow the doctor’s instructions.