Retinal vein occlusion (eye stroke)

What it is

At the back of the eye, blood drains away through retinal veins. If a vein becomes blocked, blood and fluid can build up in the retina, affecting vision. It usually affects one eye and comes on suddenly without pain.

Common symptoms

Vision change is usually sudden and painless.

• Sudden blurred or lost vision in one eye
• A dark patch or shadow in part of the vision
• Sometimes mild floaters or a red eye
• No eye pain in most cases

Causes and risk factors

It is more common with increasing age and is strongly linked to high blood pressure, diabetes, glaucoma, smoking and blood clotting problems. Because it can reflect wider circulation problems, a full health check is often recommended.

Treatment and monitoring

There is no single cure, but treatment targets complications such as swelling at the macula or abnormal new blood vessels. This may include injections into the eye, laser, or managing blood pressure and diabetes. Regular monitoring is important to protect remaining vision.