Endophthalmitis is a type of eye inflammation. It is generally caused by infection. It affects the intraocular cavities (vitreous or aqueous humor). However, noninfectious endophthalmitis may happen because of different causes:
- Toxic agents
- Retaining native lens after post- operation
There are two types of endophtalmitis-
- Endogenous (metastatic): It is the hematogenous spread of micro organisms from a different source of infection.
- Exogenous: Direct mode of infection as a complication of foreign bodies, ocular surgery and penetrating or blunt ocular trauma.
Pathophysiology Of Endophtalmitis
A natural form of resistance against the infecting organisms is the blood ocular barrier. Blood borne organisms invade the blood ocular barrier either by
- Changes in the vascular endothelium occurs when substrates are released during infection
- Direct invasion
Direct invasion by the organism or inflammatory mediators of the immune response causes destruction of the intraocular tissues. Endophtalmitis may manifest as white nodules on the iris, lens capsule, choroid or retina. The inflammation can even spread to the orbital soft tissue. Any kind of surgical procedure that creates an imbalance in the eye globe can lead to exogenous endophtalmitis (glaucoma, retinal, cataract, radial keratotomy).
Frequency Of Incidence In United States
Endogenous endophtalmitis is a rare form of disease. It occurs in only 2 to 15% of all clinical cases of endophtalmitis. The annual incidence rate is about 5 per 10,000 hospitalized patients. The right eye is at higher risk than the left eye in unilateral cases. This is due to its proximal location to arterial blood flow from right innominate artery to the right carotid artery.
The number of people who are at risk from endophthalmitis may be increasing because of several reasons. Some of them are listed below:
- Recurrent use of immuno suppressive agents
- Invasive surgical procedures like bone marrow transplant
- Spread of AIDS
