Retinal Vein Occlusion

Arteries in the body transport blood from the heart to other body parts, while the vein transports blood from different body parts back to the eye. When the veins or arteries get blocked, an occlusion or even a stroke can occur.

Obstruction of blood flow can happen in arteries due to clot formation or in veins due to a thickening of blood vessels as a result of blood vessel disease. This process can also happens in the retinal blood vessels.

The nerve cells in the retina need continuous blood supply from the blood vessels to provide the retina with nutrients and oxygen.

For a stroke to occur, a small blood clot will block blood flow through an artery in the brain, preventing the area from getting blood which causes damage.

This damage can occur in any part of body body. When the veins in the retina get blocked, it stops draining blood from the retina. The result is haemorrhage or bleeding and fluid leakage from the blocked vessels. This is called RVO (Retinal Vein Occlusion) or BRVO (Branch Retina Vein Occlusion).

Two types of retinal vein occlusion affect people.

They include:

• Central Retinal Vein Occlusion (CRVO) - This occurs from a blockage in the main retinal vein.
• Branch Retinal Vein Occlusion (BRVO) - This condition occurs due to blockage in one of the smaller retinal veins branches.

How does RVO cause reduce/ loss of vision?

• Macular Oedema

  The macula is the small, middle part of the retina that gives sharp, detailed vision, including reading vision. If fluid and blood leak into the macular, it may cause swelling, leading to a condition known as macular oedema. Macular oedema can cause blurred vision or vision loss.

• Neo-vascularisation

  RVO may cause a lack of oxygen supply of tissue and the development of new, abnormal retinal blood vessels, leading to a condition known as Neo-vascularisation. The new blood vessels are prone to blood and fluid leakage into the vitreous.

  The vitreous is a clear, jelly-like substance inside the eye. Blood and fluid in the vitreous will cause clouds or small spots called floaters in your field of vision. People with severe Neo-vascularisation may experience retinal detachment in the back of their eye to traction of this tissue.

• Neo-vascular glaucoma

  The new blood vessels in some parts of the eye can result in increased eye pressure and pain.

• Blindness

  Blindness can occur from RVO, particularly if the condition is left untreated and progresses.

Causes of RVO

RVO occurs when the retinal vein gets blocked. In some cases, it occurs because veins in the eyes are narrow. Most common risk factors are individual with high cholesterol levels, high blood pressure, diabetes, and smokers or other medical conditions that affecting blood vessels.

RVO symptoms

Symptoms of RVO range from mild to severe. Some people experience blurred vision, and vision loss may occur. The condition usually affects only one eye. Blurring or vision loss may be mild in the initial stages but worsens over hours or days. In some cases, even complete vision loss can occurs following RVO.

If you experience these symptoms, ensure you contact your eye doctor to schedule an urgent appointment. RVO can permanently damage the retina and cause irreversible vision loss and other eye problems if left untreated early diagnoses and treatment can avoid or reduce permanent damage.

RVO diagnosis

The doctor may use the following to diagnose retinal vein occlusion.

• (OCT) Optical Coherence Tomography Diagnostic Scan

  This test gives high-definition images of the retina using a scanning tomography with a high resolution. The doctor can use these images to check for oedema and swelling by measuring the retina’s thickness. The images from OCT can determine the progress of the condition during treatment. Modern versions of OCT scans are available at Optimal Vision, allow surgeons to investigate your retina’s blood vessels with advance technology without the need for injection of fluorescein dye.

• Ophthalmoscopy

  The doctor can see the changes in your retina by examining it with a slit lamp (eye microscope) and an ophthalmoscope.

• Fluorescein Angiography

  In the fluorescein angiography procedure, the doctor will inject a dye into a vein in your arm. The dye will travel to the retinal blood vessels, allowing the doctor to take images of the blood vessels.

RVO Treatment

There are many advanced treatments available for RVO which can significantly change the outcome and vision if diagnosed and treated early.

In certain cases, the blocked blood vessels will cause a build-up of fluid in the retina, like a sponge absorbing water. It may lead to the formation of new blood vessels.

Common treatments for RVO include:

• Intra vitreal injection of anti-vascular endothelial growth factor (anti-VEGF) medications

  These medications target VEGFreceptors. This is a vital growth factor that leads to macular oedema. Injections of Eylea and Lucentis and Avastin are some examples.

• Intra vitreal injection of corticosteroid drugs

  These medications treat the factors that can cause oedema. A popular treatment is injection of Azurdex (dexamethasone steroid implants).

• Focal laser therapy

  Focal laser therapy uses lasers on swollen areas to reduce oedema.

• Pan-retinal photocoagulation therapy

  This treatment aim to avoid the formation of new blood vessels when extensive retinal vein occlusion has occurs and avoid secondary complications like glaucoma or even loss of vision.

You will need follow-up appointments to monitor the progress of the disease. Detecting changes in the condition is necessary to aid in formulating treatment plans. Ensure you also inform your GP if you have retinal vein occlusion to ensure evaluation and treatment of any underlying chronic condition. 

If you experience a sudden change in your vision, feel free to visit Optional Vision or call 020 7183 3725 to book an eye doctor appointment. Our doctor will conduct the necessary tests to determine if you have retinal vein occlusion and offer the right treatment.

INTRA VITREAL INJECTION

Medications known as anti-VEGF can treat swelling and bleeding related to RVO. Treatment with Anti-VEGF helps to reduce the number of abnormal retinal blood vessels. These medications also slow leaking from unusual blood vessels.

 The doctor will administer small amount of the medication through a very small needle from white part of the eyes. This treatment is done under local anaesthesia, take few minutes and is well tolerated, no needle can be seen and has minimal discomfort.