Purpose: To explore functional and morphological retinal changes 6 months after dexamethasone intravitreal implant (DEX implant) for the treatment of macular edema due to central or branch retinal vein occlusion (CRVO, BRVO). Procedures: In this prospective interventional case series patients underwent a complete ophthalmological examination at baseline and monthly, including best-corrected visual acuity (BCVA), spectral domain-optical coherence tomography and microperimetry. Fluorescein angiography was performed at baseline and at 4 months. All patients were treated with a DEX implant and retreated according to predefined criteria starting from month 4. Results: Sixteen patients (mean age 66 ± 13 years, 14 CRVO, 2 BRVO) were included. At 6 months mean retinal sensitivity improved from 9.7 ± 4.6 to 13.6 ± 5.4 dB (p < 0.0001) while mean BCVA improved from 52.4 ± 16.2 to 66.1 ± 16.6 (p < 0.0001). Mean central retinal thickness decreased from 708.3 ± 151.01 to 362.7 ± 177.4 μm (p < 0.0001); 56.2% of eyes were retreated at month 4. Conclusions: At 6 months DEX implant led to a significant improvement in retinal sensitivity and visual acuity associated with a reduction of retinal thickness in patients with macular edema due to retinal vein occlusion.