Non-arteritic anterior ischemic optic neuropathy is the most common acute optic nerve disease in the Chinese elderly population, characterized by painless vision loss with optic disc edema. Risk factors for ischemic optic neuropathy include systemic vascular disease, commonly hypertension, hypotension, diabetes mellitus, atherosclerosis, ischemic heart disease, hyperlipidemia, and, rarely, female Fabry disease, Takayasu arteritis, carotid stenosis or embolism, carotid dysplasia, occlusive thrombophlebitis, migraine, and Raynaud’s disease. In addition, acute blood loss or hypotension, trauma, surgery, infection, inflammatory diseases, blood disorders, and thrombotic diseases can induce ! Inflammatory diseases associated with ischemic optic neuropathy include allergic vasculitis, Behcet’s disease, Buerger’s disease, Churg-Strauss disease, Crohn’s disease, mixed connective tissue disease, polyarteritis nodosa, recurrent polychondritis, rheumatoid arthritis, dry syndrome, systemic lupus erythematosus, ankylosing spondylitis, HLA-B27-associated uveitis. Non-ocular procedures associated with ischemic optic neuropathy include cardiopulmonary bypass, lumbar spine surgery, abdominal surgery, leg vein bypass, mitral valve surgery, nasal surgery, parathyroidectomy, radical prostatectomy, liver transplantation, and coronary angiography. Infectious diseases associated with ischemic optic neuropathy include Aspergillus infection, herpes zoster, Lyme disease, recurrent herpes labialis, staphylococcal infected cavernous sinus thrombosis, syphilis, AIDS, and Chlamydia pneumoniae infection. Ocular surgery associated with ischemic optic neuropathy includes cataract surgery, myopic excimer laser surgery, blepharoplasty, and retinal surgery. Hematologic disorders associated with ischemic optic neuropathy include anemia, hyperhomocysteinemia, G-6-PD deficiency syndrome, leukemia, true erythrocytosis, sickle cell disease, thrombocytopenic purpura, and macroglobulinemia.