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What is retinal vein occlusion?

Written by: Mr Praveen Patel
Edited by: Cal Murphy

While we have all heard of eye conditions like cataracts and glaucoma, one that often escapes attention is retinal vein occlusion. Despite its relative obscurity, it is one of the leading causes of sudden painless loss of sight. Mr Praveen Patel, leading London ophthalmologist, explains:

What is retinal vein occlusion?

Retinal vein occlusion (RVO) is when the small veins that carry blood away from the retina (the light-sensitive layer at the back of the eye) become blocked. The blockage forces blood and other fluids to drain into the retina, causing bleeding and swelling of the retina (macular oedema). Blockage also a lack of oxygen in the retina (hypoxia). This affects the ability of the retinal cells to receive light and send signals to the brain to create a visual image. Vision tends to become blurry as a result.


Retinal vein occlusion – quick facts:

  1. Branch retinal vein occlusion – blockage of one of the four smaller retinal veins which feed into the larger central retinal vein.
  2. Central retinal vein occlusion – blockage of the large central vein.



Retinal vein occlusion is thought to be caused by atherosclerosis (hardening of blood vessel walls) of closely associated retinal arteries and/or the formation of a blood clot blocking the small veins that carry blood away from the eye. Various things can influence the development of RVO:


Can retinal vein occlusion be cured?

While many patients regain vision, it rarely fully recovers, as it is usually impossible to remove the blockage. Treatment is focussed on preventing further bleeding and further RVOs, by managing diabetes, blood pressure and cholesterol levels. It’s also important to carry out blood tests to rule out other causes of RVO.

One of the main ways RVO causes vision loss is through the development of macular oedema (sponge-like thickening or swelling of the retina). Thankfully, there are effective treatments for macular oedema caused by RVO. These treatments are given by eye injections using a local anaesthetic and need to be given on a repeated basis to get the best results. Early treatment of macular oedema is also key as this leads to better improvements in vision.

If you experience vision loss or blurring in part of all of one of your eyes, it is essential to consult your doctor or a specialist.

By Mr Praveen Patel

Mr Praveen Patel is an internationally recognised London ophthalmologist specialising in age-related macular degeneration (AMD), retinal vein occlusion and diabetic retinopathy. He is known for his outstanding patient care, and his expertise in treating macular diseases, particularly AMD, a condition which he is actively involved in researching. He was awarded the Moorfields Research Medal for his work in the British Medical Journal on AMD, and is a member of various ophthalmological organisations. Mr Patel is one of the lead consultants for clinical trials in macular disease at Moorfields Eye Hospital, where he also has his private practice.

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