Endophthalmitis

Abstract

Bleb-related endophthalmitis is one of the most visually devastating complications of glaucoma filtering surgery. Endophthalmitis associated with a functioning filtering bleb may develop months or years postoperatively. Early postoperative endophthalmitis occurs within 6 weeks following the surgery, and late endophthalmitis occurs after this 6-week window. Early detection and rapid institution of appropriate treatment is important in optimizing outcomes and preserving vision. Blebitis is defined as an infection localized to the bleb and surrounding tissues, including the anterior chamber. Blebitis lacks vitreous involvement. Ocular signs of blebitis may include hyperemia around the bleb site, focal infiltrate in the bleb, bleb purulence, and anterior chamber reaction. Bleb-related endophthalmitis encompasses the findings of blebitis with concurrent vitreous inflammation. The presence of vitreous inflammation differentiates bleb-related endophthalmitis from blebitis (Figure 24.1). Risk factors for bleb-related infections are listed in Table 24.1. Bleb morphology and the presence of a bleb leak affect the risk of blebitis or endophthalmitis. Bleb leaks have been identified as the single most important risk factor for the development of bleb-related infections. In a case-control study by Soltau et al, Seidel-positive bleb leaks increased the risk of bleb infection nearly 26-fold. A multicenter study also found that a bleb leak is a major risk factor for blebitis and endopthalmitis. In a review of 20 endophthalmitis cases, 55% of the patients (11 patients) had a Seidel-positive leak following filtering surgery, and three-quarters (15 patients) were noted to have a thin or avascular bleb. Recurrent bleb leaks were observed in over a third of the patients. Song et al found that bleb leaks occurred in 27% of eyes (13 of 49 eyes) with delayed-onset bleb-related endophthalmitis. It is recommended that the clinician routinely monitor patients for bleb leaks and make appropriate interventions to resolve the leak once it is identified. The advent of antifibrotic agents has improved the success rate of traditional filtering surgery but has also increased the incidence of bleb-related infections. Greenfield et al demonstrated that mitomycin-C (MMC) increases the risk of bleb leak.