Combination Therapy with Anti-VEGF and Intravitreal Dexamethasone Implant for Macular Edema Secondary to Retinal Vein Occlusion

To compare the safety and efficacy of intravitreal injection of ranibizumab alone or ranibizumab combined with dexamethasone intravitreal implant in the treatment of macular edema secondary to retinal vein occlusion.