Intracameral Antibiotics and Glaucoma Surgery

Abstract

surgery. 21 Despite these statistics, there is no consensus in the glaucoma community regarding IC antibiotic prophylaxis. ' Infection in Glaucoma Surgeries Timing of Infection IC antibiotics only have utility in preventing acute postoperative endophthalmitis. Under ideal conditions, IC antibiotics maintain a minimum inhibitory concentration for up to ∼30 hours in the anterior chamber (AC). 22 In the literature, acute infections are defined as occurring <4 to 6 weeks following surgery, whereas late infections occur > 6 weeks postoperatively. Late infections are more common than acute infections following trabeculectomy 23 and are often associated with bleb leaks. 24,25 In one study, only 15% (10/68) of cases of bleb-associated endophthalmitis (BAE) occurred within 1 month of surgery. 26 Late infections are also more common than acute infections following GDI surgery and are often associated with late tube exposures. 27,28 Since MIGS are relatively new, and the devices vary, it is unclear whether endophthalmitis will more often be acute (like after traditional cataract surgery) or late (like after traditional glaucoma surgery). This will probably vary based on whether a conjunctival bleb is formed, like in the case of the XEN Gel Stent (XGS) (Allergan, Abbvie Company, Irvine, CA, USA), and whether corneal incisions are made, which can act as a gateway for periocular bacteria in the immediate postoperative period. Even though late infections tend to be common, acute infections still confer significant morbidity for glaucoma patients.In fact, acute postoperative endophthalmitis occurs 3 times as often following glaucoma surgery than cataract surgery according to data from the Intelligent Research in Sight (IRIS) registry from 2013 to 2017. Before the widespread adoption of IC antibiotics for cataract surgery, the rate of acute endophthalmitis was 0.08% for cataract surgery and 0.12% for glaucoma filtering surgeries. 29 After evidence supporting IC antibiotics in cataract surgery emerged, the rate of acute endophthalmitis halved to 0.04% following cataract surgery alone, but remained at 0.12% following cataract surgery combined with glaucoma surgery. This may be because IC antibiotics have not been studied in the setting of glaucoma surgery, though this has yet to be determined. 21 Since, theoretically, only acute infections are prevented by the use of IC antibiotics, Table 1 summarizes the estimated incidence of overall and acute infection for each of the major glaucoma surgeries. Rate of Infection After TrabeculectomyTrabeculectomy is the second most common glaucoma surgery following MIGS. 1,2 The exact rate of infection after trabeculectomy is 126 ' Marando et al