Functional and Anatomical Outcomes Following Intravitreal Bevacizumab in Treatment-Naïve Centre-Involving Diabetic Macular Edema: A 3-Month Prospective Evaluation

Introduction: Diabetic macular edema (DME) remains a major cause of vision impairment worldwide. Intravitreal bevacizumab, though used off-label, is an established therapy for centre-involved DME (CI-DME). This study evaluated how effectively microperimetry complements standard measures—best-corrected visual acuity (BCVA) and central macular thickness (CMT)—in assessing treatment outcomes. Methods: In this prospective observational study, 52 eyes with treatment-naïve CI-DME received three monthly bevacizumab injections. BCVA, CMT (via OCT), and mean retinal sensitivity (by microperimetry) were recorded at baseline, one month, and three months. Statistical analyses included the Wilcoxon signed-rank test for repeated measures and Spearman’s rank correlation for structure–function relationships. Results: After three months, mean BCVA improved from 0.50 ± 0.095 to 0.67 ± 0.088 (p < 0.001), while CMT decreased from 401.9 ± 87.6 µm to 329.5 ± 23.2 µm (p < 0.001). Mean retinal sensitivity rose from 14.96 ± 1.01 dB to 16.50 ± 1.39 dB (p < 0.001). Improvement in BCVA correlated positively with both CMT reduction (ρ = 0.340, p = 0.014) and sensitivity gain (ρ = 0.412, p = 0.004), while CMT reduction correlated inversely with sensitivity improvement (ρ = –0.367, p = 0.009). Conclusion: Three consecutive bevacizumab injections resulted in significant anatomical and functional recovery in eyes with CI-DME. The consistent correlations between macular structure and function underscore the value of microperimetry as a sensitive, complementary tool for evaluating therapeutic response beyond standard acuity and OCT metrics.