Effectiveness of Biosimilar Ranibizumab in the Management of Diabetic Macular Edema: A Retrospective Observational Cohort Study

This study is a retrospective observational cohort designed to evaluate the real-world effectiveness and safety of intravitreal ranibizumab biosimilar in patients with diabetic macular edema (DME). Medical records of adult patients diagnosed with type 1 or type 2 diabetes mellitus who received at least one injection of ranibizumab biosimilar at the Retina Unit, Department of Ophthalmology, Benha University Hospitals, between January 2022 and April 2026 will be reviewed. Eligible cases will include eyes with center-involving DME confirmed by optical coherence tomography (OCT) and a minimum follow-up period of 3-6 months. Baseline demographic, systemic, and ocular characteristics, including age, sex, diabetes duration, HbA1c level, lens status, prior ocular treatment, best-corrected visual acuity (BCVA), and central macular thickness (CMT), will be collected. Follow-up data will include changes in BCVA and CMT, number of injections received, and treatment regimen (loading dose, pro re nata, or treat-and-extend protocols). Outcomes will assess mean changes in BCVA and CMT from baseline to final follow-up, as well as the proportion of eyes achieving clinically meaningful visual and anatomical improvement. Safety outcomes will include ocular adverse events such as endophthalmitis, intraocular inflammation, retinal detachment, and intraocular pressure elevation, as well as systemic thromboembolic events. Statistical analysis will be performed using SPSS software, with appropriate parametric or non-parametric tests applied based on data distribution, and a p-value <0.05 considered statistically significant. The study will be conducted following Institutional Review Board approval and in accordance with the Declaration of Helsinki, with all data anonymized to ensure patient confidentiality.