Retina Vein Occlusion (RVO)

RVO is a blockage of the veins that carry blood away from the retina of the eye.  Blockage caused by RVO can cause fluid to leak into the macula and cause swelling which is called macular edema.  This can cause blurred vision and sometimes complete vision loss.  

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Although the blockage caused by RVO cannot be reversed, treatments are available that may slow down the progression of vision loss and in some cases improve your vision.  Once diagnosed with an RVO Dr. Varma will refer you for a cardiovascular workup if you have not had one recently.  This will be to rule out any cardiovascular risk factors such as hypertension, hardening of the arteries, high cholesterol, cardiovascular disease (stroke, coronary artery disease), and the presence of blood clots.  You should see your family physician for a full physical.

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Understanding how the eye works

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Our eyes are like a camera.  The iris and the pupil control how much light come into the eye, the lens helps focus the light to create a clear picture on the retina.  The retina is a light-sensitive layer at the back of the eye that acts like the film in a camera.  It captures the images focused by the lens and sends the images as signals to the brain.  The macula is the center of the retina and is responsible for detailed central vision.  The optic nerve sends signals from the retina to the brain to interpret the image.  When you have AMD it affects this process.

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Veins in your eyes, retinal veins, are an important part of blood circulation and are needed to help you see well.  The main job of these veins is to move blood out of your eye.  RVO occurs when one of these veins becomes blocked.  This blockage happens without warning.  There are two types of vein occlusions: branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO).

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What is a Branch retinal vein occlusion (BRVO)?

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BRVO is the most common type of retinal vein occlusion.  It usually happens when atherosclerosis causes damage to the retinal arteries.  This makes the arteries hard, so they press on a retinal vein.  This causes the retinal vein to narrow, leading to increased pressure, cell damage, and ultimately a blocked retinal vein.  This blockage causes your body to release an increased amount of vascular endothelial growth factor (VEGF).  The high concentration of VEGF weakens the walls of the branched retinal vein, making it easier for fluids to pass through.  This causes blood vessels to leak fluid and blood into the central portion of the retina resulting in swelling, otherwise known as macular edema.  

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BRVO is a painless disease, causing blurred or distorted vision. If left untreated BRVO can cause a number of eye complications, resulting in mild to significant vision loss. The primary cause of vision loss is due to a buildup of fluid from leaky blood vessels in the macula.  This build-up of fluid results in swelling and thickening of the macula called macular edema.

 

What is a Central Retinal Vein Occlusion (CRVO)?

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CRVO is caused when a blockage occurs in the central retinal vein, preventing blood flow from the eye.  CRVO is painless, however, left untreated it can result in severe eye complications and vision loss.  The primary cause of vision loss is due to a buildup of fluid from leaky blood vessels in the visually sensitive center portion of the retina (macula).  This build-up of fluid results in the swelling and thickening of the macula (macular edema).

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There are a number of factors that can increase your risk of RVO, some of which are controllable and some which are not.  They are as follows:

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Controllable: weight control, blood pressure control, diabetes (keeping blood sugars low), bleeding and 

                     clotting disorders, smoking, lack of exercise, high cholesterol

Uncontrollable: Age and underlying eye disease such as glaucoma.

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The treatment for vein occlusions is a series of anti-VEGF injections. In some cases, retinal laser may be required.

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Living with a Vein Occlusion

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Anti-VEGF therapy has been shown to be a successful treatment for retinal vein occlusions, however, there are some simple lifestyle changes you can make to slow the progression of the disease. They are as follows:

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• Make sure to keep your regularly scheduled appointments with Dr. Varma to ensure close monitoring of your disease.

• Monitor and report any vision changes to the office as soon as possible.  You will be given an Amsler grid and instructed on its proper use.  This is a grid or series of horizontal and vertical lines with a black dot in the center.  When you look at the grid you will focus on the black dot and check to see how the lines appear to you.  When you first start using the grid you may already have some areas of distortion and it is helpful to mark these areas.  You should check your Amsler grid daily with each eye separately and report any new areas of distortion.

• Do not smoke, if you do smoke you should consider stopping even if it means speaking to your family physician to get help.

• Eat a healthy well-balanced diet with fresh fruit, dark green leafy vegetables, foods high in Omega 3s (ie: fish and nuts).

• Exercise regularly to maintain a healthy weight.

• Wear sunglasses to protect your eyes from UV rays.

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Coping with vision loss​

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Vision loss can be challenging and life-changing. It can impact your everyday life and make you less independent.  It will take time to adjust to living with vision loss whether it be minimal or extensive.  The CNIB (Canadian National Institute for the Blind) has many resources for coping with vision loss. If this is something you are interested in Dr. Varma can refer you to them.