Persistent diabetic macular edema: Definition, incidence, biomarkers, and treatment methods

Intravitreal antivascular endothelial growth factor (anti-VEGF) treatment has drastically im -proved the visual and anatomical outcomes in patients with diabetic macular edema (DME); however, success is not always guaranteed, and a proportion of these eyes demonstrate per-sistent DME (pDME) despite intensive treatment. While standardized criteria to define these treatment-resistant eyes have not yet been established, many studies refer to eyes with no clinical response or an unsatisfactory partial response as having pDME. A patient is con-sidered to have pDME if the retinal thickness improves less than 10-25% after 6 months of treatment. A range of treatment options have been recommended for eyes with pDME, including switching anti-VEGF agents, using corticosteroids and/or antioxidant drugs in ad-junct with anti-VEGF therapy, and vitrectomy. In addition, multimodal imaging of DME eyes may be advantageous in predicting the responsiveness to treatment; this is beneficial when initiating alternative therapies. We explore the literature on persistent DME regarding its defining criteria, incidence, the baseline biological markers that may be useful in anticipat-ing the response to treatment, and the available treatment options.(c) 2022 Elsevier Inc. All rights reserved.