Infectious Endophthalmitis After Intravitreal Anti-VEGF Injections at a Tertiary Hospital, Ahvaz, Iran: Incidence, Features, Management, and Microorganism Identification

Background: Intravitreal injections (IVIs) are currently the most rapidly increasing procedure in both ophthalmology and medicine overall. They are commonly used for conditions such as diabetic retinopathy (DR), macular edema, and age-related macular degeneration (AMD) associated with venous occlusive disease. The most frequently administered injections involve anti-angiogenic agents, including aflibercept, bevacizumab, and ranibizumab. Although these injections are effective, they carry a slight risk of infectious endophthalmitis (IEO), which could severely impact vision. Objectives: This retrospective case series presents the clinical and microbiological characteristics, visual outcomes, and incidence of IEO following IVIs at Imam Khomeini Hospital, Ahvaz, Iran. Methods: This retrospective case series, conducted from April 2021 to July 2024, examined the incidence, clinical characteristics, management strategies, and microorganism identification in cases of acute IEO after intravitreal anti-vascular endothelial growth factor (VEGF) injections, using billing records. Inclusion criteria involved examining the records of 15 patients with clinical symptoms of acute IEO out of a total of 7,396 injections administered during the study period. Patients with incomplete data were excluded. Nine patients received intravitreal antibiotic injections (IVAI), which included dexamethasone (0.4 mg/0.1 mL), ceftazidime (2 mg/0.1 mL), and vancomycin (1 mg/0.1 mL). Five cases received IVAI and dexamethasone (0.4 mg/0.1 mL), followed by pars plana vitrectomy (PPV) a few days later. Additionally, one patient underwent PPV with the administration of intravitreal antibiotic agents at the end of the surgery (IVAIES). The primary outcome measures focused on the effectiveness of infection control using IVAI and dexamethasone as standalone treatments, compared to early PPV followed by IVAIES. Results: During the study, 7,396 IVIs were analyzed, with 15 cases of IEO identified, resulting in an overall incidence rate of 0.2%. Positive intraocular cultures were obtained in 40% (6 out of 15) of the post-injection cases, with most infections linked to Enterococci. Conclusions: Acute IEO after intravitreal anti-VEGF injections is a rare but potentially serious complication. It can often be effectively controlled with IVAI and a vitreous tap. However, if there is no response to initial treatment (IVAI) and vitritis persists, the possibility of infection by uncommon pathogens should be considered, potentially necessitating further intervention such as vitrectomy.