Purpose: This study aimed to compare the effects of intravitreal dexamethasone (IVDx) implants on branch retinal vein occlusions (BRVOs) and macular vein occlusions (MVOs). Methods: Seventeen consecutive patients with MVO and 18 patients with BRVO, whose foveal thicknesses were greater than 300 mu m, were recruited for this study. BRVO and MVO patients were diagnosed by means of fundus fluorescein angiography. Patients were treatment-naive. Initially, each patient in both the BRVO and MVO groups received an IVDx implant, and then apro re nataIVDx regimen was initiated. Primary outcomes included VA gain, intraocular pressure (IOP) changes, macular ischemia, central macular thickness, retinal neovascularization, and number of IVDx injections. Follow-up time was 12 months. Results: The MVO group initially had significantly lower central macular thickness and a lower percentage of macular ischemia and systemic hypertension than those in the BRVO group (p = 0.001, 0.045, and 0.010, respectively). There was a statistically significant VA gain in both groups (p < 0.001), but the VA gain of the MVO group was greater than that of the BRVO group (p < 0.001). The mean total number of IVDx injections administered throughout the study period was significantly lower in the MVO group than in the BRVO group (1.3 +/- 0.4 vs 2.0 +/- 0.0;p = 0.001). Discussion: MVO and BRVO have different disease characteristics, and IVDx implants were more effective on the visual gain in patients with MVO than that of patients with BRVO who had higher numbers of IVDx injections.