Endophthalmitis is a severe inflammation of the interior of the eye caused by the introduction of contaminating micro-organisms following trauma, surgery or haematogenous spread from a distant infection site. Despite appropriate therapeutic intervention, bacterial endophthalmitis frequently results in visual loss, if not loss of the eye itself.
The two types of endophthalmitis are endogenous (metastatic) and exogenous. Endogenous endophthalmitis results from the haematogenous spread of organisms from a distant source of infection (i.e. endocarditis). Endogenous endophthalmitis is rare, occurring in only 2–15 % of all cases of endophthalmitis. Average annual incidence is about five per 10,000 hospitalised patients. In unilateral cases, the right eye is twice as likely to become infected as the left eye, probably because of its more proximal location to direct arterial blood flow from the right innominate artery to the right carotid artery.
Since 1980, candidal infections reported in intravenous drug users have increased. The number of people at risk may be increasing because of the spread of AIDS, more frequent use of immunosuppressive agents and more invasive procedures (i.e. bone marrow transplantation).1 Exogenous endophthalmitis results from direct inoculation as a complication of ocular surgery, foreign bodies and/or blunt or penetrating ocular trauma. Most cases of exogenous endophthalmitis (about 60 %) occur after intraocular surgery. Under normal circumstances, the blood–ocular barrier provides a natural resistance against invading organisms.2
Destruction of intraocular tissues may be due to direct invasion by the organism and/or inflammatory mediators of the immune response. Endophthalmitis may be as subtle as white nodules on the lens capsule, iris, retina or choroid. It can also be as ubiquitous as inflammation of all the ocular tissues, leading to a globe full of purulent exudates. In addition, inflammation can spread to involve the orbital soft tissue.
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