Retinal Vein Occlusion

What is Retinal Vein Occlusion?

Retinal vein occlusion (RVO) is the second most common retinal vascular disorder after diabetic retinopathy. It occurs when one of the veins draining blood from the retina becomes blocked, causing a back-up of blood and fluid that leads to retinal haemorrhages, macular oedema and, if untreated, permanent visual impairment. It most commonly affects people over 50, particularly those with hypertension, high cholesterol, or cardiovascular disease.

Symptoms

• Sudden painless loss or blurring of vision in one eye
• Distortion or grey area in central vision
• Sector-specific visual field loss (branch RVO)
• Floaters (from retinal haemorrhages)

Causes

• Hypertension — the most important risk factor
• Hypercholesterolaemia
• Diabetes mellitus
• Glaucoma — raised intraocular pressure compresses the vein at the optic disc
• Thrombophilia (clotting disorders) in younger patients

Diagnosis

Dilated fundus examination, optical coherence tomography (OCT) to quantify macular oedema, fundus fluorescein angiography (FFA) to assess retinal perfusion. Systemic investigation to identify cardiovascular risk factors.

Treatment

Intravitreal anti-VEGF injections (aflibercept, ranibizumab) are the first-line treatment for macular oedema associated with RVO, and have transformed visual outcomes. Intravitreal steroid implants (dexamethasone intravitreal implant) are an alternative, particularly for pseudophakic patients. Systemic cardiovascular risk factor modification is essential to reduce the risk of further vascular events.