Infectious optic neuropathy

Infections can damage the optic nerve in various manners: optic disc edema due to generalized uveitis or inflammation spread from adjacent retinochoroidal tissues; primary optic disc involvement; primary retrobulbar optic nerve involvement; optic nerve sheath involvement causing perineuritis; compression or spread from orbital or sinus involvement; papilledema from elevated intracranial pressure in the setting of meningitis; or retrobulbar optic neuritis in the setting of meningitis. Infectious agents include viruses, bacteria, spirochetes, parasites, and fungi. Presentations may vary depending on immunocompetency status and are often rapidly progressive with associated ocular, orbital, or neurologic features. A crucial step in evaluating a patient with optic neuropathy is determination of immune status because immunosuppressed patients can have atypical presentations and multiple co-infections and are at risk for uncommon infections. Immunosuppression can be due to HIV; immunosuppressive agents, including chronic prednisone, chemotherapies, and immunotherapies; or immunosenescence.