AIM: To evaluate the changes in macular morphology and function after a single intravitreal injection of aflibercept in diabetic macular edema (DME) using optical coherence tomography angiography (OCTA) and MP-3 microperimetry. METHODS: Twenty-eight patients (42 eyes) diagnosed with DME were treated with intravitreal injection of aflibercept. The changes in best corrected visual acuity (BCVA), central retinal thickness (CRT), foveal avascular zone (FAZ) area, vessel density of superficial retinal capillary plexus (SVD), vessel density of deep retinal capillary plexus (DVD), mean light sensitivity (MLS), 2° fixation rate (P1), 4° fixation rate (P2), and other indicators 1mo after treatment were compared; of these, BCVA was converted into logarithm of the minimum angle of resolution (logMAR), and the correlation among the factors was analyzed. RESULTS: After treatment, logMAR BCVA was 0.47±0.24, which was significantly better than that before treatment (0.63±0.28, P<0.001). The CRT was 359.21±107.87 μm after treatment, which was significantly lower than before treatment (474.10±138.20 μm, P<0.001). The FAZ area, SVD, and DVD were not significantly changed after treatment compared with the baseline. MLS was 22.16±4.20 dB after treatment, which was significantly higher than before treatment (19.63±4.23 dB, P<0.001). P2 significantly increased after treatment than before treatment (P=0.007). P1 had no significant change after treatment than before treatment (P=0.086). CONCLUSION: A single intravitreal injection of aflibercept effectively reduces macular edema and improves retinal sensitivity, fixation stability, and visual acuity, possibly without causing significant changes in the retinal vascular condition in a short time.