The eye in systemic infection.

Bacterial, fungal, viral, and parasitic pathogens all cause systemic infection and can spread to the eye. Dissemination of pathogens via the bloodstream can lead to direct involvement of the eye. Visual loss is common in bacterial or fungal endophthalmitis, and toxoplasmosis is a major cause of ocular morbidity and poor vision after congenital or acquired infection. Some infections cause intraocular damage by indirect mechanisms (eg, HIV-mediated immunosuppression), leading to opportunistic infections such as cytomegalovirus infection, periocular nerve involvement due to leprosy, and hypersensitivity reactions in tuberculosis. Eye symptoms might indicate the outcome of an underlying infection, such as development of retinal ischaemia in severe malaria, which is associated with a poor prognosis. Successful outcome for patients with ocular infection depends on close collaboration between clinicians identifying and treating underlying disease, specialist ophthalmic review, and ophthalmic interventional skills (when needed).