Substances that can cause optic neurotoxicity: Carbon disulfide/carbon tetrachloride Ethanol Ethylene glycol Methanol Thallium Tobacco Drugs that can damage the optic nerve: Amiodarone Cyclosporine Nitrogen mustard phenylbutyrate Chloramphenicol Cisplatin Dithiramethion Ethambutol Halogenated Hydroxyquinolone Isoniazid Penicillamine Sildenafil Streptomycin Vitamin deficiencies: B12 B1 (Ammonium sulphate deficiency = foot fungus) B6 (Niacin deficiency = pellagra)