ImportanceMonitoring for and reporting potential cases of intraocular inflammation (IOI) in clinical practice despite limited occurrences in clinical trials, including experiences with relatively new intravitreal agents, such as brolucizumab, pegcetacoplan, or faricimab, helps balance potential benefits and risks of these agents.ObjectiveTo provide descriptions of 3 initially culture-negative cases of acute, severe, posterior-segment IOI events occurring within the same month following intravitreal faricimab injections at a single institution.Design, Setting, and ParticipantsIn this case series, 3 patients manifesting acute, severe IOI following intravitreal injection of faricimab were identified between September 20, 2023, and October 20, 2023.ExposureFaricimab, 6 mg (0.05 mL of 120 mg/mL solution), for neovascular age-related macular degeneration among patients previously treated with aflibercept; 1 patient also had prior exposure to bevacizumab.Main Outcomes and MeasuresVisual acuity, vitreous taps for bacterial or fungal cultures, and retinal imaging.ResultsAll 3 patients received intravitreal faricimab injections between September 20 and October 20, 2023, from 2 different lot numbers (expiration dates, July 2025) at 3 locations of 1 institution among 3 of 19 retina physicians. Visual acuities with correction were 20/63 OS for patient 1, 20/40 OD for patient 2, and 20/20 OS for patient 3 prior to injection. All 3 patients developed acute, severe inflammation involving the anterior and posterior segment within 3 to 4 days after injection, with visual acuities of hand motion OS, counting fingers OD, and hand motion OS, respectively. Two patients were continuing faricimab treatment while 1 patient was initiating faricimab treatment. All received intravitreal ceftazidime, 2.2 mg/0.1 mL, and vancomycin, 1 mg/0.1 mL, immediately following vitreous taps. All vitreous tap culture results were negative. One patient underwent vitrectomy 1 day following presentation. Intraoperative vitreous culture grew 1 colony of Staphylococcus epidermidis, judged a likely contaminant by infectious disease specialists. All symptoms resolved within 1 month; visual acuities with correction were 20/100 OS for patient 1, 20/50 OD for patient 2, and 20/30 OS for patient 3.Conclusions and RelevanceIn this case series, 3 patients with acute, severe IOI within 1 month at 3 different locations among 3 ophthalmologists of 1 institution following intravitreal faricimab could represent some unknown storage or handling problem. However, this cluster suggests such inflammatory events may be more common than anticipated from faricimab trial reports, emphasizing the continued need for vigilance to detect and report such cases following regulatory approval.