Occlusion of the central retinal vein (CRVO); hemiretinal occlusion (HRVO) occurs when the superior and inferior retinal drainage does not merge into a central retinal vein (20%) and is occluded (more like CRVO than BRVO).

BRVO is a venous occlusion at any branch of the central retinal vein. Occlusions occurring at the proximal part of the central retinal vein trunk results in an HRVO, which is considered a subtype of either CRVO or BRVO.

Nov 1, 2013 · Second only to diabetic retinopathy as a leading cause of retinal vascular blindness, retinal vein occlusion (RVO) is often linked with systemic risk factors such as hypertension, arteriosclerosis, diabetes, and smoking and with other ocular diseases such as glaucoma.

Jan 1, 2018 · Hemiretinal vein occlusion (HRVO): occlusion at the disc, involving either the superior or inferior hemiretina; Branch retinal vein occlusion (BRVO): occlusion of a tributary vein, typically at the site of an arteriovenous crossing; thought to be caused by com­pression from an overlying atheroscle­rotic arteriole

Nov 15, 2004 · Depending on the location of venous blockage, retinal vein occlusion (RVO) is classified as branch retinal vein occlusion (BRVO), central retinal vein occlusion (CRVO), or hemi-retinal vein occlusion (HRVO). This article reviews the pathogenesis, natural history and management of each of these forms of RVO.

Retinal vein occlusion is divided into 3 different types—central retinal vein occlusion (CRVO), hemiretinal vein occlusion (HRVO), and branch retinal vein occlusion (BRVO). Patients with these conditions usually present with a sudden painless loss of vision in one eye.

Retinal vein occlusions are blockages of the central retinal vein or one of its branches. They are more common in older people, people with high blood pressure, high cholesterol and those with a history of heart attacks, strokes, diabetes or glaucoma. Patients may notice sudden or gradual painless loss of vision or visual field defect.