RETINAL VEIN OCCLUSION

WHAT IS RETINAL VEIN OCCLUSION (RVO)

The front of the eye contains a lens that focuses images on the inside of the back of the eye. This area is the retina. The retina is where the eye focuses the images we see. It is covered with special nerve cells which convert light into signals that are sent via the optic nerve to the brain, where they are recognized as images. Conditions that affect the retina affect the ability to see.

Arteries carry blood from the heart to other parts of the body, and veins carry the blood back to the heart. A blockage in an artery or vein is called an occlusion or stroke. When the flow of blood from the retina is blocked, it is often because a blot clot is blocking the retinal vein. This condition is called retinal vein occlusion (RVO).

TYPES OF RETINAL VEIN OCCLUSION:

There are two types of retinal vein occlusion:

•  Central retinal vein occlusion (CRVO) is the blockage of the main retinal vein.

•  Branch retinal vein occlusion (BRVO) is the blockage of one of the smaller branch veins.

CAUSES OF RETINAL VEIN OCCLUSION:

Retinal vein occlusion happens when a blood clot blocks the vein. Sometimes it happens because the veins of the eye are too narrow. It is more likely to occur in people with diabetes, and possibly high blood pressure, high cholesterol levels, or other health problems that affect blood flow.

SYMPTOMS:

•  Blurry or missing vision in part or all of an eye

•  Dark spots or lines floating in your vision

•  Pain and pressure in the eye.

HOW DOES RETINAL VEIN OCCLUSION (RVO) CAUSE VISION LOSS?

•  Macular Edema: 

The macula is the small, central area of the retina that allows sharp, detailed vision, such as that necessary for reading. Blood and fluid leaking into the macula cause swelling, a condition called macular edema, which causes blurring and/or loss of vision.

• Neovascularization: 

•  Retinal vein occlusion can cause the retina to develop new, abnormal blood vessels, a condition called neovascularization. These new vessels may leak blood or fluid into the vitreous, the jelly-like substance that fills the inside of the eye. Small spots or clouds, called floaters, may appear in the field of vision. With severe neovascularization, the retina may detach from the back of the eye.

•  Neovascular glaucoma: New blood vessels in certain parts of the eye can cause pain and a dangerous increase in pressure inside the eye.

•  Blindness: 

 The complications of Retinal vein occlusion, especially if they are not treated, can lead to irreversible loss of vision.

HOW DO YOU DIAGNOSE RETINAL VEIN OCCLUSIONS?

• Optical coherence tomography (OCT):

This is a high definition image of the retina taken by a scanning ophthalmoscope with a resolution of 5 microns. These images can determine the presence of swelling and edema by measuring the thickness of your retina. The doctor will use OCT images to objectively document the progress of the disease throughout the course of your treatment.

• Ophthalmoscopy:

The changes caused by RVO may be seen by examination of the retina with an instrument called an ophthalmoscope.

• Fluorescein angiography: 

This is a test procedure in which a dye that is injected into a vein in the arm travels to the retinal blood vessels. Special photographs allow the physician to see the vessels.

TREATMENT:

There’s no cure for retinal vein occlusion. Your doctor can’t unblock the retinal veins. What they can do is treat any complications and protect your vision. They may recommend:

Injections:

A drug called anti-vascular endothelial growth factor targets substances that cause fluid buildup in a part of your retina called the macula, which provides your central vision and helps you see details like fine print. This helps to ease swelling. Or your doctor may give you steroid injections in your eye instead. Your doctor will apply a pain-numbing drug first and use a very thin needle, so you shouldn't feel much discomfort.

Laser surgery: 

    A laser burns and seals off blood vessels near the macula. This keeps them from leaking. The retina does not have pain nerves, so you should not feel much discomfort.
You may need this if you grow new blood vessels in your eye. Your doctor will use a laser to make tiny burns on the retina. It stops the vessels from leaking and growing.
These treatments may help you get your vision back. Most people’s eyesight will get better after a few months. But some may not see any improvements.

PREVENTION:

Usually, an underlying medical condition brings on a retinal vein occlusion. So it’s important to keep your blood pressure, cholesterol, and blood sugar under control. If you have diabetes, get your eyes checked every year.

If you take birth control pills, talk to your doctor. Rarely, they can lead to retinal vein occlusion.

MANAGING THE RISK FACTORS:

• Managing your blood sugar levels if you have diabetes
• Lowering your blood pressure if you've been diagnosed with hypertension (high blood pressure)
• Bringing down high cholesterol levels
• Getting advice on stopping smoking

Can you drive with retinal vein occlusion?

Yes- if you can read the minimum standards of vision.

If you have any questions or concerns, speak to your ophthalmologist for advice.

WORKING WITH RETINAL VEIN OCCLUSION:

    You'll probably need regular treatment for retinal vein occlusion, with follow-up appointments over several years. It's a good idea to speak to your employer about your diagnosis. They should make reasonable adjustments for you, such as giving you time to attend appointments.

    If you develop vision problems in the affected eye, which is often the case with central retinal vein occlusion, you could still work with some adjustments. Employers must make reasonable adjustments to help you. You may need to explain the kind of things that could help, for example:

• Low vision aids such as magnifiers to help with reading.

• Large print materials or products, such as keyboards and phones.

• Screen reader software and other technology.

SUPPORT FOR PEOPLE LIVING WITH RETINAL VEIN OCCLUSION:

Being diagnosed with retinal vein occlusion can be a worrying time. You're likely to be facing a lot of follow-up appointments for treatment over a long time. You may feel nervous about the possibility of complications. And, especially with central retinal vein occlusion, you may have to deal with visual loss in the affected eye.

Try talking to family and friends about your feelings. They may support you better if they understand how you feel. It can also help to speak to other people who've had retinal vein occlusion.

 If you're dealing with central vision loss, there are tips and products, support and services to help you be as independent as possible and continue with a good quality of life. Your ophthalmologist or eye clinic may refer you for a low vision assessment to explore the useful vision you have and the visual aids that will make the most of it. Local social services can support you in keeping safe at home and getting around safely if sight loss affects your mobility.

Practical ideas to help make the most of your vision include:

•  Using plenty of bright and even lighting at home.

•  Low vision aids like magnifiers that help you to see details. Some simple, low-tech solutions, like phones with large numbers and large print keyboards, can make life easier.

•  Everyday technology. You can read books, newspapers, and magazines on e-readers and tablets in large text. Computers and phones can read your messages out loud. You can also get clever tech such as talking microwaves and weighing scales.

FREQUENTLY ASKED QUESTIONS:

• Is retinal vein occlusion a disability?

    Retinal vein occlusion normally affects one eye rather than both. Even with loss of vision in the affected eye, if you have good vision in the other eye, you may not be classed as having a disability.

•  Can you fly with a branch retinal vein occlusion?

    Flying is not thought to make retinal vein occlusion worse. However, if you have anti-VEGF injections or other treatments, ask your ophthalmologist for device.

•  How long does retinal vein occlusion last?

    The symptoms of retinal vein occlusion-blurred vision and visual loss-can develop quickly. Complications such as new abnormal blood vessels, macular oedema and neovascular glaucoma may not develop until months after the initial blockage in the retina. Treatments such as intravitreal injections of anti-VEGF medicine can be needed at regular intervals up to four to many years after diagnosis.