**2. Incidence**

The incidence of BRI is difficult to determine because of variable modes and times of presentation. Long-term studies are useful in ascertaining the lifetime risk of BRI, which is important to discuss with patients as part of the informed consent process.

In the Collaborative Initial Glaucoma Treatment Study, the 5-year risk of blebitis and bleb related endophthalmitis (BRE) was 1.5% and 1.1%, respectively [2]. In the Tube Versus Trabeculectomy Study, [3] the 5-year incidence of BRI following trabeculectomy was 4.8% (n = 105). A 20-year study (n = 460) reported cumulative probabilities of blebitis and BRE of 2% and 5%, respectively [4].

In the trabeculectomy versus tube trial, at 5 years, blebitis and endophthalmitis occurred in 1% and 4.8% of cases in the tube and trabeculectomy groups, respectively, but this was not statistically significant [3]. In a large case series of GDD implantations, exposed implants were more likely to be associated with infection than the group generally (16% v 1%), and exposed inferior GDD had a higher rate of infection compared to superior y placed GDD (47% v 8%) [5]. Multiple studies have shown a higher rate of endophthalmitis in patients younger than 18 years of age [6]. Removal of GDD in the clinical setting of BRI is controversial but recommended by the author once the infection has been treated.

The reported rate of BRI after various nonpenetrating surgeries has been 0–1.6% [7–10]. Cases of BRI in this setting usually occur after laser goniopuncture [10]. In a large case series (n = 199) with relatively short follow-up there was 1 case of late onset endophthalmitis following XEN 45 gel stent implantation [11]. Apart from this, there have been a few case reports of BRE following XEN 45 implantation [12–15]. In the author's experience, after 5 years of follow up of 90 eyes implanted with XEN45 gel stent, there were no cases of BRI (unpublished data). One case of BRE has been reported following bleb needling in an eye implanted with microshunt [16].
