Objectives: The objectives of this study were to evaluate the structural and functional outcomes after the loading phase with brolucizumab in switched patients with diabetic macular edema (DME) and to identify potential predictive biomarkers of treatment response. Methods: A total of 28 eyes with DME, switched to brolucizumab, were retrospectively reviewed. Main outcomes during the follow-up period, up to 6 weeks after the fifth injection, included changes in best-corrected visual acuity (BCVA), central subfield thickness (CST), macular volume, subfoveal choroidal thickness, intraretinal and subretinal fluid (IRF and SRF), cyst dimension including maximal horizontal cyst diameter (MHCD), maximal vertical cyst diameter (MVCD), width-to-height ratio (WHR), foveal avascular zone (FAZ) dimension, and vessel density (VD). Results: At the last follow-up, BCVA was significantly improved (p = 0.003). Significant reduction of CST was demonstrated after each injection time point (p < 0.05), and a dry macula was detected in 64.3% of patients at the last follow-up. The WHR was 1.23 ± 0.46, and a negative correlation to final CST (p < 0.0001) was found. In FAZ and VD analysis, no significant variation was detected. At the last disease activity assessment, the treatment regimen was q12 in 64% of patients. Conclusions: Brolucizumab leads to anatomical and functional improvements in switched eyes affected by DME. WHR may represent a predictive biomarker of treatment response.
