Efficacy and safety of posterior subtenon interferon alfa-2B injection in recurrent inflammatory macular edema

Purpose: This study aimed to evaluate the efficacy of posterior subtenon injection of interferon alfa-2B (PSII) as a therapeutic option for managing recurrent inflammatory macular edema (IME). Methods: A retrospective study was conducted at a tertiary care eye center in South India. Patients receiving PSII for recurrent infectious or non-infectious IME were included in the study. Recurrent IME was defined as less than 50 μm improvement in central macular thickness (CMT) on spectral-domain optical coherence tomography within 1 month or relapse of IME within 3 months of previous treatment. Patients received a single PSII (1 MIU/mL) under topical anesthesia. Follow-up visits included clinical examinations and CMT measurement, best-corrected visual acuity (BCVA), and intraocular pressure (IOP). Results: The study included 13 patients with a mean age of 46.2 years. Diagnosis varied, including pseudophakic IME, post-endophthalmitis IME, and various forms of uveitis. Mean CMT significantly reduced from 639.0 μm at baseline to 427.45 μm at one week ( P < 0.001). But further increased to 500.62 μm at 1–2 months follow-up ( P < 0.05). Mean BCVA improved from 20/70 (0.57 logMAR) to 20/40 (0.33 logMAR) at 1-month follow-up. No significant adverse effects were observed, although one patient with post-endophthalmitis IME developed granulomatous anterior uveitis 40 days after the injection. Conclusion: The study demonstrates the potential short-term efficacy of PSII in reducing CMT and improving BCVA in patients with recurrent IME. Further research is needed to optimize dosing protocols and explore long-term efficacy.