Exogenous Endophthalmitis: Post-Operative versus Post-Intravitreal Injection

Abstract

Endophthalmitis is a potentially vision-threatening complication associated with nearly every intraocular or periocular procedure, including cataract surgery and intravitreal injection. Post-operative endophthalmitis after cataract surgery is a familiar entity with well-established features and treatment. However, infectious endophthalmitis after intravitreal injection is not as well understood. The current widespread use of intravitreal injections of vascular endothelial growth factor (VEGF) antagonists has raised increasing concern for post-injection endophthalmitis. Endophthalmitis associated with intravitreal injections occurs with a similar low incidence rate as endophthalmitis associated with cataract surgery. Post-surgical and post-injection endophthalmitis exhibit similar clinical features, though post-injection endophthalmitis might present slightly earlier. These entities share the most common causative organism, Staphylococcus epidermidis , although there is a higher incidence of more virulent and resistant organisms such as Streptococcal species in post-injection endophthalmitis. The proportion of eyes with a culture-negative endophthalmitis has been found more commonly after intravitreal injection, raising concerns for distinguishing infectious endophthalmitis from “sterile endophthalmitis” which may be associated with anti-VEGF therapy. The Endophthalmitis Vitrectomy Study (EVS) guides the treatment of exogenous endophthalmitis after cataract extraction. The treatment of post-injection endophthalmitis is an area of new interest with emerging literature of clinic presentation and therapeutic management.