Retinal Vein Occlusion

Occurs when a thrombus blocks a retinal vein

Aetiology

• Endothelial damage e.g. diabetes

• Abnormal blood flow e.g. hypertension

• Hypercoaguable state e.g. cancer

Pathophysiology

• Central retinal vein occlusion: occurs when a thrombus forms in the retinal veins and blocks the drainage of blood from the retina

• Branch retinal vein occlusion: venous occlusion at any branch of the central retinal vein resulting in visual problems in the area drained by that branch

• Blockage of a retinal vein causes pooling of blood in the retina, resulting in leakage of fluid and blood causing macular oedema and retinal haemorrhages

• This results in damage to the tissue in the retina and loss of vision

• It also leads to the release of VEGF, which stimulates the development of new blood vessels (neovascularisation)

Clinical presentation

Symptoms

• Sudden or gradual painless visual loss

• Blurred vision

• Visual field defects (sectoral in BRVO)

Signs

• “Blood and thunder” fundus appearance

• Dilated and tortuous retinal veins

• Widespread retinal hemorrhages

• Cotton wool spots

• Optic disc edema

• Sectoral retinal hemorrhages and edema

• Dilated tortuous veins in the affected quadrant

Investigations

Fundoscopy

• Flame and blot haemorrhages

• Optic disc oedema

• Macula oedema

• Dilated tortuous veins

Management

• Immediate referral to opthalmology

• Management in secondary care aims to treat macular oedema and prevent complications such as neovascularisation - laser photocoagulation, intravitreal steroids, anti-VEGF