Retinal vein occlusion

What is a retinal vein occlusion?

Occlusion (blockage) of a retinal vein is a common cause of sudden painless reduction in vision in older people. The retina is the thin membrane that lines the inner surface of the back of your eye. Its function is similar to that of the film in a camera. Blockage of one of the veins draining blood out of the eye causes blood and other fluids to leak into the retina, causing bruising and swelling as well as lack of oxygen. This interferes with the light receptor cells and reduces vision. The condition is uncommon under the age of 60 but becomes more frequent in later life.

What are the symptoms of retinal vein occlusion?

Blurred vision without pain.

What causes retinal vein occlusion?

A blockage forms in the vein, usually due to a blood clot, and obstructs the blood flow. The exact cause is unknown, but several conditions make the condition more likely. These include:

High blood pressure: If your blood pressure is consistently higher than your GP thinks it should be, treatment is normally advised.
High cholesterol: Treatment with tablets is normally highly effective.
Glaucoma: With this common eye condition, the pressure in the eye is raised. This can cause gradual loss of side vision. It also increases the risk of retinal vein occlusion. Treatment with drops to reduce the pressure is normally highly effective in preserving sight and preventing further retinal vein occlusions.
Diabetes: Retinal vein occlusions are more common in people with diabetes. Detection and treatment of diabetes is highly effective in preserving vision and preventing further retinal vein occlusions.
Smoking: The more you smoke, the greater the risk of another vein occlusion. Please speak to your GP if you need help to stop smoking. You can also call the Smokefree National Helpline for advice on 0800 022 4332 or visit their website.
Certain rare blood disorders: These are normally identified by simple blood tests. In the unlikely event that treatment is required, this will be supervised by a specialist in blood disorders.

Preventing a return of retinal vein occlusion

It is essential to identify and treat any risk factors such as the ones above, to minimise the risk to the other eye and prevent a further vein occlusion in the affected eye. Treatment of any risk factors dramatically reduces the risk of a further vein occlusion occurring in either eye. Without treatment, there is a high risk of retinal vein occlusion returning. This can cause further damage to the sight of the affected eye as well as damage to the sight of the other eye. In a small number of cases, no risk factors can be found, with the cause being unknown.