Technology & Screenings


Our Expertise


Our eyes are made of lots of big and small blood vessels, the mains ones being where the blood reaches through a main retinal artery supplying oxygen to the retina and leaving through a main retinal vein, draining the de-oxygenated blood.

RVO occurs when the main retinal vein or one of the small branches becomes blocked. As a result, blood and fluid can start to leak which may cause a sudden loss of vision. RVO also compromises the blood flow and the amount of oxygen reaching the eye which can cause the growth of abnormal blood vessels and affect the function of the macula- this is the portion of the retina responsible for central vision.

Central Retinal Vein Occlusion Macula OCT

Macular Oedema (swelling) secondary to Retinal Vein Occlusion (RVO)

Branch Retinal Vein Occlusion (BRVO): Obstruction of a branch of retinal vein(s) which drain specific areas of the retina.

Central Retinal Vein Occlusion (CRVO): Obstruction of the main vein formed from the four branches which drain blood from the retina.

It is not always known; however, blood tests and blood pressure checks may be requested to identify the cause. Various contributing factors include:

  • High blood pressure
  • Diabetes
  • Raised cholesterol levels
  • Smoking
  • Ageing

Macular Oedema (MO) is the accumulation of fluid in the macula.

The macula is the part of the retina which gives you sharp, straight-ahead vision, e.g. watching television or recognising faces, and being able to see finer detail vision.

Macular oedema is usually caused by abnormal leakage from damaged blood vessels. The accumulation of fluid causes the macula to swell which blurs and distorts vision. Grey shadowed areas are formed where the oedema is present due to Central Retinal Vein Occlusion.

Retinal vein occlusion The Retina Clinic, London.

The grey shadowed areas are where Oedema is present due to Central Retinal Vein Occlusion

How Is Retinal Vein Occlusion Diagnosed?

There are a number of diagnostic tests that need to be conducted. Please refer to the Technology heading to find out more about our state of the art equipment.

To investigate and evaluate the integrity of the retina after a vein occlusion has occurred it is best to carry out the Optos® Ultra-Widefield Retinal Scan, Swept-Source DRI Topcon Triton® OCT Angiography Scan, Swept-Source DRI Topcon Triton® OCT Scan, Canon Xephilio® S1 Widefield Swept Source Optical Coherence Tomography (SS-OCT)

This diagnostic test allows for the assessment of blood flow from the central to the far periphery of the retina. Standard retinal cameras cannot capture detailed images of the peripheral retina. There is the need for an injection of dye in the vein of your arm. No radiation is used. These broad views of the retinal enable earlier diagnosis and tailored treatment planning and management of your condition.

Central Retinal Vein Occlusion The Retina Clinic London

We are fortunate at The Retina Clinic London to have the latest imaging technology including brand new ultra-widefield OCT angiography. This technology measures blood  flow in up to 80% of the retina in a non-invasive manner without the need of an injection of dye in the vein of your arm. This is an important diagnostic test for the early diagnosis of a change in or loss of blood supply. Compared to most OCT angiography devices, we are able to see the full extent of damage caused by a retinal vein occlusion. 

Central Retinal Vein Occlusion UWF OCT-A

An ultra-widefield OCT angiography scan showing patches of the retina where blood flow has been reduced due to the occlusion

This advanced optical coherence tomography (OCT) imaging technology allows for improved identification of layers within the retina with a wider field of view so that more of your retina can be visualised at once. 

This technology enables Prof. Stanga to identify oedema (fluid) within or under the retina; identify oedema in the periphery of the retina; objectively maps and measures retinal thickness, guides diagnosis and treatment, and monitors response.

Most OCT devices in daily clinical practice have a field of view limited to the macula or central part of the retina. However, the macula is only one small part of the retina and being able to visualise as much as possible of the back of your eye is key to ensuring that the correct treatment plan is devised for you. 

Central Retinal Vein Occlusion Macula OCT

An OCT scan showing macular oedema as a result of a retinal vein occlusion

This is a imaging procedure which involves injecting a vegetable die into the patient and then imaging their retina as the dye passes through using a light at a specific wavelength to reflect off of the dye. This imaging effectively shows the extent of fluid accumulation beneath the macula and whether there is any further damage to the vasculature of the retina.

How Is Retinal Vein Occlusion Treated?

Once all diagnostic tests have been completed, Prof Stanga will discuss with you a tailored treatment plan. This could include a combination of therapies such as intravitreal injections of: the new bispecific antibody targeting VEGF-A and angiopoetin-2, anti-VEGF, slow-released dexamethasone implant, and ultra-widefield fundus fluorescein angiogram and ultra-widefield OCT angiography-guided retinal laser to prevent abnormal vessel growth. You can find more information on these types of treatments under the treatment options on this website.

Treatment is tailored based on individual patient’s clinical findings and needs. 

Ensuring your blood pressure and cholesterol levels are well-controlled is an essential part of achieving an effective treatment and outcome.