Eyes & Vision

Central Retinal Vein Occlusion (CRVO)

Central retinal vein occlusion causes sudden or subacute painless unilateral visual loss with widespread retinal haemorrhages and macular oedema; distinguish non-ischaemic from ischaemic disease because ischaemia carries a high risk of iris/angle neovascularisation and neovascular glaucoma.

Definition

Central retinal vein occlusion is obstruction of the central retinal vein causing raised retinal venous pressure, widespread retinal haemorrhage, macular oedema and variable retinal ischaemia. It is classified clinically as non-ischaemic or ischaemic according to perfusion and the risk of neovascular complications.

First principles

One obstructed vein affects the whole retina

The central retinal vein drains the retinal circulation. Occlusion raises venous and capillary pressure, causing widespread haemorrhage and leakage of fluid into the retina and macula. Macular oedema is a major cause of central visual loss, while retinal non-perfusion creates the risk of neovascularisation.

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