Retinal Vein Occlusion and Macular Odema
What is Retinal Vein Occlusion (RVO)?
Blood reaches the retina through a main artery and leaves through a main vein. Both of these have smaller branches which supply oxygen to the retina and drain de-oxygenated blood.
RVO occurs when the main 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.
Types of Retinal Vein Occlusion (RVO)
Branch Retinal Vein Occlusion (BRVO): Obstruction a branch 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.
What causes Retinal Vein Occlusion (RVO)?
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
Raised cholesterol levels
What is Macular Oedema (MO)?
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.
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.
How is Retinal Vein Occlusion diagnosed?
You will undergo Slit-Lamp Biomicroscopy and one or more of the following:
Optos® Ultra-Widefield Retinal Scan
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.
Swept-Source DRI Topcon Triton® OCT Angiography Scan
This is a new OCT test which allows for the assessment of retinal blood flow in the central part 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.
Swept-Source DRI Topcon Triton® OCT Scan
This new and advanced optical coherence tomography (OCT) imaging technology allows for improved identification of layers within the retina.
This technology enables Prof. Stanga to identify oedema (fluid) within or under the retina; objectively maps and measures retinal thickness, guides diagnosis and treatment, and monitors response.
How is Retinal Vein Occlusion treated?
Prof. Stanga will discuss with you available treatment options.
Treatment is tailored based on the stage of disease and may include one or more of the following: anti-VEGF, steroid injections, and Pascal® laser.
Laser treatment can be applied to either a localised area or the entire retina with the exception of the macula, or both.
If intraocular injections are required, Prof. Stanga will clean your eye and the surrounding skin with an antibacterial solution and numb the eye with anaesthetic drops. This is followed by an injection into the white of the eye.
The number of injections required varies according to the stage of the disease and individual patient response to treatment. The injections often start on a monthly basis and then are spread out as the condition improves.
If left untreated, vision can continue to deteriorate and treatment may no longer be an option.
Ensuring your blood pressure and cholesterol levels are well-controlled is an essential part of achieving an effective treatment and outcome.
The injections may cause slight discomfort, but most patients do not feel any pain.