**1. Introduction**

Trabeculectomy with antimetabolites is the most commonly performed glaucoma surgery worldwide [1], being indicated for cases of progressive optic neuropathy despite maximum medical therapy. Other forms of drainage surgery include glaucoma drainage device (GDD) implantation, XEN45 gel stent, microshunt implantation and non-penetrating glaucoma surgery such as deep sclerectomy (DS).

Bleb-related infections (BRI), although rare can be very aggressive with poor prognosis and variable response to antimicrobial therapy. BRI includes blebitis and endophthalmitis, which may represent a continuum of infection. Early onset BRI occurs within 1 month of surgery and late onset BRI is defined as occurring after 1 month.

Several studies have addressed the possible risk factors associated with BRI and new surgical techniques have been developed to improve safety. In this chapter, we will discuss the risk factors for BRI following trabeculectomy, the pathogens involved, the treatment protocol and antimicrobial agents that are typically used in treatment.
