Etiology 1. Inflammatory demyelination is the more common cause. The exact cause of inflammatory demyelinating neuritis is unknown, but it is likely due to some prodromal factor such as upper respiratory or gastrointestinal viral infection, psychological shock, vaccination, etc. that causes the body’s autoimmune response, producing autoantibodies that attack the myelin sheath of the optic nerve and cause the disease. 2. Infections Local and systemic infections can involve the optic nerve and lead to infectious optic neuritis. (1) Local infections such as intraocular and intraorbital inflammation, oral inflammation, middle ear and mastoiditis, and intracranial infections can be directly caused by local spread of optic neuritis. (2) Systemic infections certain infectious diseases can lead to optic neuritis, such as: diphtheria (diphtheria bacillus), scarlet fever (streptococcus), pneumonia (pneumococcus, staphylococcus), dysentery (dysentery bacillus), typhoid fever (typhoid bacillus), tuberculosis (tuberculosis bacillus), purulent meningitis, septicemia and other systemic bacterial infectious diseases, the pathogens of which can enter the blood stream, grow and multiply in the blood, release toxins, and cause optic neuritis. cause inflammation of the optic nerve. Viral diseases such as influenza, measles, mumps, herpes zoster, chickenpox, and parasitic infections such as Lyme spirochetes, leptospira, syphilis spirochetes, toxoplasmosis, toxoplasmosis, coccidiosis, etc. have been reported to cause optic neuritis. 3. Autoimmune diseases such as systemic lupus erythematosus, Wegener’s granulomatosis, Behcet’s disease, desiccation syndrome, and nodular disease can cause nonspecific inflammation of the optic nerve. In addition to the above causes, the etiology cannot be identified in some clinical cases; some of these patients may have Leber hereditary optic nerve.