Protein threads inside the eyes may be caused by filamentous keratitis, white thin stripes of foreign bodies, allergic conjunctivitis and so on. 1. Filamentous keratitis: belonging to the immune disease, usually the patient’s eyes have obvious foreign body sensation, photophobia, ocular surface examination can be seen in the corneal epithelium with hyperplasia of the filamentous material, which is protein thread-like and can be sliding. After surgical treatment to remove the protein threads, drops of prednisolone acetate, levofloxacin and other anti-infective. 2. White thin stripes of foreign bodies: when the airborne tiny foreign bodies such as woolen threads enter the eyes, adhere to the cornea or conjunctiva, may be protein thread-like, patients feel itchy, tearing, usually blinking, washing the eyes can be removed, and in severe cases, surgical removal. 3. Allergic conjunctivitis: If protein threads appear in the conjunctiva part of the eye, it may also be due to allergic conjunctivitis, which is usually accompanied by conjunctival congestion, itchy eyes, and eye swelling. Treatment with glucocorticoids, such as dexamethasone to combat the inflammation, after a period of time the symptoms can be relieved. Once protein lines appear in the eyes, it is recommended to go to the hospital for examination, to clarify the cause of the disease, to treat the cause, and to follow the doctor’s instructions for the use of medication.