What is retinal vein occlusion?
A retinal vein occlusion occurs when a vein carrying blood away from the retina becomes blocked.
Retinal vein occlusion is sometimes described as a type of “eye stroke” because it involves a blockage in the retinal circulation. More precisely, it affects a vein that drains blood away from the retina, causing increased pressure, bleeding and fluid leakage within the retinal tissue.
This differs from a retinal artery occlusion, where the incoming blood supply to the retina is suddenly interrupted.
There are two main types:
- Branch retinal vein occlusion, known as BRVO, affects one of the smaller retinal veins and usually involves part of the retina.
- Central retinal vein occlusion, known as CRVO, affects the main vein draining the retina and can involve a larger area.
Retinal vein occlusion can cause a sudden or progressive change in vision and should be assessed promptly by a retinal specialist.
What symptoms can it cause?
Symptoms may include:
- Sudden or developing blurred vision
- A dark, shadowed or missing patch in the vision
- Distorted central vision
- Floaters
- Reduced vision in one eye
- Difficulty reading or recognising faces if the macula is affected
The severity of symptoms depends on the position and extent of the blockage, whether the macula is swollen and how much of the retinal circulation is affected.
Some patients experience a marked change in vision, while others notice only a mild blur or patch of distortion.
Why does retinal vein occlusion happen?
Retinal vein occlusion is often associated with changes in blood vessel health.
Risk factors may include:
- High blood pressure
- Diabetes
- Raised cholesterol
- Glaucoma or raised pressure inside the eye
- Smoking
- Cardiovascular disease
- Certain blood-clotting disorders
In some patients, further medical investigation is advised to identify and manage wider health risks.
The Retina Clinic London can work with the patient’s GP or physician to ensure that relevant factors such as blood pressure, diabetes, cholesterol and cardiovascular health are reviewed appropriately.
How is retinal vein occlusion diagnosed?
Diagnosis begins with a detailed retinal examination and advanced imaging.
At The Retina Clinic London, assessment may include:
- Optical coherence tomography, known as OCT, to detect and measure macular swelling
- Ultra-widefield retinal imaging to document retinal bleeding and other changes across the central and peripheral retina
- OCT angiography to assess retinal blood flow and identify areas of reduced circulation or abnormal new blood vessels
- Fluorescein angiography to identify leakage, reduced blood supply and disease activity
- Visual acuity testing to measure how the condition is affecting vision
Reduced blood supply to part of the retina is known as retinal ischaemia. In some cases, ischaemia can lead to neovascularisation, which is the growth of fragile abnormal blood vessels.
Together, these investigations show the type and severity of the vein occlusion, identify complications and guide a personalised treatment plan.
What treatments are available?
There is currently no approved treatment that physically unblocks the affected retinal vein. Treatment is therefore directed at the effects of the occlusion, including macular swelling, retinal leakage, reduced circulation and abnormal new blood vessel growth.
Treatment depends on whether the retinal vein occlusion is causing macular oedema, retinal ischaemia, abnormal blood vessel growth or other complications.
Treatment may include:
- Anti-VEGF eye injections to reduce macular swelling and improve or stabilise vision
- Steroid injections or implants in selected cases of macular oedema
- Retinal laser treatment where there is significant ischaemia, leakage or abnormal new blood vessel growth
- Careful monitoring when the condition is mild and stable
- Vitrectomy surgery in selected severe or complicated cases
- Management of underlying medical risk factors with the patient’s GP or physician
Anti-VEGF injections are a principal treatment for macular oedema caused by retinal vein occlusion. Treatment often begins with injections at relatively close intervals so that swelling can be brought under control.
As the retina responds and becomes more stable, the consultant will aim to extend the interval between treatments as safely as possible. The timing is personalised using visual assessment and OCT imaging, with the aim of maintaining control while reducing the frequency of injections and appointments where appropriate.
Steroid treatment may be considered where clinically appropriate. The consultant will explain its potential benefits and the need to monitor for side effects, including raised eye pressure and cataract.
Retinal laser is used selectively. It can treat areas of poor retinal circulation or abnormal new blood vessel growth and reduce the risk of further complications.
The aim of treatment is to control the consequences of the occlusion, reduce swelling, protect the retina and preserve or improve as much useful vision as possible.
Why does specialist follow-up matter?
Retinal vein occlusion can change over time.
Macular swelling may improve and later return. Areas of poor circulation may also lead to abnormal new blood vessels in the retina or at the front of the eye.
Some patients need a course of injections, while others require laser treatment or careful observation.
Close follow-up allows the consultant to:
- Measure changes in retinal swelling
- Assess the response to treatment
- Adjust the timing of injections
- Monitor retinal blood flow
- Identify abnormal new blood vessels promptly
- Review eye pressure and treatment-related side effects
Our approach
The Retina Clinic London provides consultant-led assessment and treatment for retinal vein occlusion and other retinal vascular conditions.
Our approach combines high-resolution OCT, ultra-widefield OCT angiography, ultra-widefield fluorescein angiography and detailed retinal examination to establish the type and severity of the occlusion.
Patients receive a personalised treatment and monitoring plan based on their imaging findings, visual needs and wider health.
Where appropriate, treatment may include anti-VEGF injections, steroid therapy, targeted retinal laser or surgery. We also work with the patient’s GP or physician to ensure that relevant systemic risk factors are identified and managed.
Our aim is to provide a clear diagnosis, prompt access to treatment and close follow-up throughout the patient’s care.
The next step
If you have sudden blurred vision, a dark patch in your vision or have been told that you may have a retinal vein occlusion, arrange a specialist retinal consultation promptly.
A sudden severe reduction or loss of vision requires urgent ophthalmic assessment.
To book your consultation, please call us on +44 (0)20 4548 5310 or visit https://www.theretinacliniclondon.com/book-a-consultation/
We’ll be glad to guide you through the next steps.