Endophthalmitis is an infection inside the eye. It most commonly occurs following surgery. Cataract surgery is the most frequent etiology, but it can also occur following glaucoma surgery, intravitreal injections, or rarely retina surgery. The incidence of endophthalmitis following cataract surgery has been reported to be from 0.012% to 1.3%.¹ By definition, it occurs within 6 weeks of anterior segment surgery, but usually it presents within the first week after surgery. The most common organisms are coagulase-negative Staphylococcus species, Streptococcus species, and gram-negative organisms, specifically Pseudomonas species.¹

Posttraumatic endophthalmitis is associated with an open globe injury and has been reported to have an incidence as high as 15% to 30%.^2,3 The clinical presentation is variable and can be both rapidly progressive, as in posttraumatic Bacillus endophthalmitis, or more indolent, as in posttraumatic fungal endophthalmitis. In contrast to endophthalmitis following surgery, Streptococcus pneumoniae and gram-negative bacilli are much more prominent in these cases, although Staphylococcal infections also occur.³ Bacillus cereus needs to be assumed in those cases with a soil-contaminated intraocular foreign body. The prognosis of posttraumatic endophthalmitis is much worse and can result in loss of the eye within hours after the injury.

Endogenous endophthalmitis via hematogenous spread of infectious organisms is rare, with an incidence of 0.04% to 0.4% but requires an extensive systemic workup and rapid treatment.⁴ Endogenous endophthalmitis has been associated with intravenous drug use, endocarditis, diabetes mellitus, immune compromise, malignancy, prolonged hospital admission, and intravenous antibiotic administration.⁵ Worldwide, common causes included liver abscesses, closely followed by pneumonia, endocarditis, sustained intravenous catheters, and meningitis. In cases of suspected
endophthalmitis, while actively addressing the infection of the eye, it is important to simultaneously investigate for the underlying source of hematogenous spread.

Patients with retinal inflammatory syndromes from infection are typically immunocompromised and present with gradually decreasing vision and floaters. These infectious triggers lead to a severe immune-mediated inflammatory cascade on the retina and an obliterative vasculitis. Infections are most commonly caused by members of the herpes virus family (varicella zoster, herpes simplex viruses, cytomegalovirus, and Epstein-Barr virus). Other pathogens can result in retinal inflammation and should be considered in patients with known disease and eye symptoms, including syphilis, tuberculosis, toxoplasmosis, toxocariasis, Lyme disease, and West Nile virus. Viral meningoencephalitis has also been reported in association with viral necrotizing retinitis.