Treat and extend protocol outcomes in diabetic macular edema: A narrative review

The objective of this study was to pool available data on change in visual acuity, number of injections, and change in central subfield thickness as reported by treat and extend (T&E) regimens for diabetic macular edema (DME) compared to monthly and pro re nata (PRN) regimens. PubMed, ScienceDirect, and EMBASE databases were queried for studies that met the following criteria: Retrospective or prospective design, T&E regimen reported in comparison to a monthly or PRN regimen for the treatment of DME, and a 12-month follow-up period. Eighty candidate publications were screened. Sixteen studies were included in the qualitative synthesis, 11 of which were rejected due to their observational methods. Five studies were included in the final analysis. T&E protocols for DME have been shown to be as effective as PRN or monthly treatment protocols with the added benefit of fewer office visits and minimized injection frequency.