Corneal scratches caused by OK lenses may be caused by scratches on the lenses, unclean lenses, or foreign objects under the lenses. 1. Scratches on lenses: In the process of using OK lenses, too much force, too long nails, and wrong cleaning techniques may lead to different degrees of scratches on the lenses. These scratches may cause damage to the corneal epithelial cells, resulting in the phenomenon of OK lenses scratching the cornea. 2. Unclean lenses: After a period of time, the lenses may have protein or oil deposits, and the accumulation of more deposits will reduce the oxygen permeability of the lenses, resulting in the cornea becoming fragile due to the lack of oxygen, which will make it easy for OK lenses to scratch the cornea. 3. Foreign matter under the lens: If the environment is dusty or the hands are not clean, foreign matter such as eyelashes, cotton wool, dust and so on may be adhered to the inner surface of the lens, which will cause the corneal epithelium friction and scratch the cornea after wearing the lens. When OK lens scratches the cornea, it is recommended to stop using it immediately and go to the hospital as soon as possible to have an eye examination and follow the doctor’s instructions for treatment to avoid deterioration.