Retinal vein occlusion is an eye condition caused by a blockage in one of the blood vessels at the back of the eye. There are two types of retinal vein occlusion, branch retinal vein occlusion (BRVO) and central vein occlusion (CRVO), which can affect the eye in different ways. This guide explains the differences between them, and how they can be detected during an eye test.

What is central retinal vein occlusion

Central retinal vein occlusion (CRVO) refers to the blockage of the main retinal vein, which drains blood from the retina (the layer at the back of eye). Blockage of this vein can cause blood and excess fluid to build-up and leak into the retina, collecting in the area responsible for central vision, called the macula. This fluid build-up can lead to a condition called macula oedema, where the macula swells and thickens, leading to distorted vision.

Over time, this fluid build-up can damage the light receptors in the retina and smaller capillaries in the eye, which can lead to reduced and blurry vision.

What is branch retinal vein occlusion?

Branch retinal vein occlusion (BRVO) tends to be more common, and it affects one of the smaller branch veins that each carry blood away from one quarter of the retina and feed into the central retinal vein. It has similar features to CRVO, except they are confined to the portion of the eye drained by the affected vein, so reduced vision may only be experienced in a specific section.

What are the symptoms of retinal vein occlusion?

The symptoms for retinal vein occlusion vary from mild to severe vision loss, depending on the size and location of the blocked vein and whether the central retina becomes involved. Your vision can be severely affected if the flow of blood stops completely; this may happen suddenly or gradually depending on the blockage.

Symptoms to look out for include:

  • Blurry or lost vision in part or all of the eye
  • Seeing floating dark spots or lines

If you have any of these symptoms, book an eye test with your optician as soon as possible.

What causes a retinal vein occlusion?

The most common cause of retinal vein occlusion is thought to be atherosclerosis, a condition that causes plaque (a mixture of fat, calcium and other things found in blood) to build up inside the arteries, restricting blood flow.

There are also several factors that could potentially put people at a higher risk of developing a retinal vein occlusion. These include:

  • High blood pressure (hypertension) - it’s estimated that around 65%
    of the UK population aged 65 and over experience this1
  • Diabetes
  • High cholesterol
  • Glaucoma
  • Certain blood disorders
  • Smoking

Is retinal vein occlusion common?

Retinal vein occlusion is fairly rare under the age of 60 but becomes more common in later life. Globally, an estimated 16.4 million adults are affected by RVO (2.5 million by CRVO and 13.9 million by BRVO).3

How is retinal vein occlusion detected?

OCT scans can be particularly useful in detecting retinal vein occlusion, as they provide a very detailed 3D image of the back of the eye and all the layers that make up the retina. They take just a few seconds to complete, and can be easily added to your normal eye test.

With a baseline image on file, your optometrist will be able to check your results against national averages to spot anything that might indicate the presence of an occlusion. One of the main things they’ll be looking at is the thickness of the retinal layers to check for any swelling or fluid build-up.

OCT scans can also be used to examine the macula (the centre of the retina that is responsible for the detail in the images we see) to check for signs of macular oedema which can develop as a result of an occlusion.

Why are regular OCT scans important in managing retinal vein occlusion?

If you have been diagnosed with a retinal vein occlusion, you will be referred to an eye specialist (ophthalmologist) who will decide the best treatment type for you.

Most treatment types are focused on preventing further occlusions developing and preserving your vision. Whichever treatment type you have, you will need to see your ophthalmologist regularly to assess whether your treatment is working, and to make sure you aren’t developing any complications.

Regular OCT scans can be used to keep an eye on retinal layer thickness, to ensure that your treatment plan is effective. OCT is particularly useful for this because it can detect any changes which other testing, such as fluorescein angiography (a special dye that makes the eye’s blood vessels easy to see for imaging), can sometimes miss.2 It’s likely that you’ll need to be monitored for a couple of years.

Can OCT help manage vascular eye issues?

Examination of the eye with an OCT scan provides the optometrist with a unique perspective. It allows direct evaluation of microscopic blood vessels. This is useful in making an accurate diagnosis and guiding appropriate treatment for many vascular eye issues.

By getting your eyes scanned regularly, your eye specialist will be able to monitor any progression or recurring vascular eye issues, which can help prevent any deterioration to your sight.

To find out more about vascular eye issues and their diagnosis, head to our OCT resource, where you can also book an appointment with an optician to learn more about this test.

What is the best treatment for retinal vein occlusion?

Several treatments are available to reduce bruising and swelling at the centre of the retina. Currently there is no treatment available that will restore vision in the affected eye which is why prevention is so important. Treatments include:

  • Intravitreal injection of Anti-VEGF treatment - anti-vascular endothelial growth factor (anti-VEGF) can help to reduce leakage from blood vessels. These are given by injection into the eye every month or two depending on what is best for your condition.
  • Laser treatment - laser treatment is sometimes used on its own or with other treatments to help stabilise your central vision. In a few cases, laser treatment can help with bleeding and swelling which means your vision may improve, but in most cases, it simply halts any further damage happening.
  • Steroids injections – if laser treatment isn’t an option, steroids can also be used to control the swelling which will pause any damage and can improve the condition.

Discover more

If you are displaying any symptoms of retinal vein occlusion, book an appointment with a Specsavers optometrist as soon as possible to have your vision checked. To learn more about optical coherence tomography, visit our OCT resource, or head to our eye conditions hub for information on other conditions and symptoms.

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  1. CG127 Hypertension: Clinical management of primary hypertension in adults. (August 2011). Accessed 10 March 2020.
  2. Accessed 10 March 2020.
  3. Accessed 30 November 2021.