Diabetic macular edema: Anti-VEGF Therapy and predictors of response

Abstract

Diabetic macular edema (DME) is a major cause of visual impairment in people with diabetes, but eyes with similar retinal thickness can follow different courses during treatment. This narrative critical review examines the effectiveness of intravitreal vascular endothelial growth factor (VEGF) inhibition and the clinical, structural, and treatment-related characteristics associated with visual and anatomical response. PubMed/MEDLINE-indexed clinical trials, secondary analyses, observational cohorts, evidence syntheses, and current professional recommendations were examined through 2026, with particular attention to center-involved DME. Randomized trials support anti-VEGF treatment for most eyes with reduced visual acuity, although the comparative advantage of individual agents depends partly on pretreatment vision and the treatment strategy. Faricimab and higher-dose aflibercept can extend injection intervals in selected patients without sacrificing short- to medium-term visual efficacy under trial conditions. Baseline acuity, age, glycemic status, and prior retinal damage help explain outcome variation. Optical coherence tomography features, especially inner retinal disorganization and photoreceptor-layer disruption, provide prognostic information, but they do not yet establish a validated algorithm for selecting a specific drug. Early functional response is informative, whereas residual thickness alone should not define failure. Effective individualization requires repeated assessment of acuity, retinal morphology, treatment exposure, and feasibility of follow-up.