ABSTRACT
Central retinal vein occlusion (CRVO) and branch retinal vein occlusion are common retinal vascular disorders. Hemodilution has been proposed as a method to reduce abnormal blood viscosity to treat retinal vein occlusion. Vitrectomy has been advocated by some authors to manage retinal vein occlusion with persistent macular edema. The Central Vein Occlusion Study demonstrated that the natural history of untreated macular edema is poor in many patients. The increase in retinal capillary permeability and subsequent retinal edema may be the result of a breakdown of the blood–retina barrier mediated in part by vascular endothelial growth factor. Greenberg and Martidis studied both eyes of one patient with bilateral diffuse macular edema secondary to CRVO. The majority of current local drug delivery approaches for retinal vein occlusion target macular edema because visual acuity loss in retinal vein occlusion is more often a result of macular edema than from neovascular complications.
