Epidemiology, Prevalence and Incidence in Branch Retinal Vein Occlusion and Macular Edema

Retinal vein oclusion(RVO) is the second most common retinal vascular disease after diabetic retinopathy. RVO exists in two subtypes: CRVO (central retinal vein occlusion), which is less common and represents occlusion of central retinal vein, and BRVO (branch retinal vein occlusion),which is 4–6 times more common and represents occlusion of some branches of central retinal vein. RVO is a relatively common and frequently devastating cause of visual loss mainly in older patients.Its prevalence varies according to studies in overall populations from 5.2 to 16 per 1000. Visual acuity is primarily decreased due to macular edema and retinal ischemia.