Optical coherence tomography biomarkers in patients with diabetic macular edema treated with dexamethasone implants

Beyond conventional optical coherence tomography (OCT)-based morphological classifications of diabetic macular edema (DME), an expanding range of OCT-derived biomarkers has been identified that reflect distinct pathophysiological mechanisms and may carry diagnostic, prognostic, and therapeutic relevance. We summarize current evidence on potential OCT biomarkers in DME, with a particular focus on their role in patients treated with intravitreal dexamethasone implants. We conducted a structured literature search using PubMed to identify relevant clinical and imaging studies. OCT biomarkers are discussed according to their principal clinical utility: diagnostic, such as central retinal thickness and central subfield thickness; prognostic, including hyperreflective retinal foci, disorganization of the retinal inner layers, and disruption of the ellipsoid zone and external limiting membrane; and therapeutic markers, encompassing subretinal fluid, intraretinal fluid, intracystic hyperreflective material, and vitreomacular interface abnormalities. The concurrent presence and longitudinal evolution of these OCT biomarkers may assist in patient stratification, prediction of treatment response, and personalization of therapeutic strategies with dexamethasone implants. Nevertheless, robust prospective and comparative studies are required to validate their predictive value across heterogeneous DME populations. In parallel, artificial intelligence and machine-learning approaches are expected to further refine OCT-based phenotyping and outcome prediction.