RETINAL ARTERY OCCLUSION
Retinal artery occlusion happens when blood flow is blocked in the retina. Without blood flow, the cells in the retina don’t get enough oxygen and can start to die within minutes or hours. If treatment is not sought right away your eyesight could be permanently damaged. There are two types of Retinal Artery Occlusion. Branch Retinal Artery Occlusion (BRAO) and Central Retinal Artery Occlusion (CRAO). Here at the Annan Retinal Eye Center we treat both.
Branch Retinal Artery Occlusion
A BRAO usually occurs suddenly and can cause an abrupt loss of peripheral vision. In some cases, you may also lose central vision. A BRAO affects less than 50% of the entire retina and it may or may not include the macula. Usually the cause is a clot or plaque that breaks away from the main artery in the neck or from one of the valves or chambers in the heart.
What causes it?
Most people who suffer from BRAO have one or a combination of the following:
High Blood Pressure
“This image was originally published in the Retina Image Bank® website.
Author: Hamid Ahmadieh, MD. Photographer: Solmaz Shahmohammad. Lattice Degeneration and Choroidal Nevus. Retina Image Bank. 2015; 25882. © the American Society of Retina Specialists."
The main symptom is a sudden change in sight. It almost always happens in only one eye but is usually pain free and can leave you with minimum vision. Rarely, your vision will return on its own. However, if you have a less serious blockage in the smaller arteries, your vision may go back to normal about 80% of the time.
Loss of all or part of your sight
Not able to see out of the side of your eyes
Blurry or distorted vision
At the Annan Retina Eye Center, we will examine your eyes thoroughly and discuss with you in detail your previous medical history. We will ask you to read the eye chart and check your retina for any blockages or bleeding. Other tests we may conduct include:
Visual Field Test – Looking into a machine you click a button each time you see a light. The machine examines any loss in peripheral vision.
Fluorescein Angiography - We will inject a harmless dye in your arm which will move through your bloodstream to your retina. A special camera takes pictures of your eye to show which blood vessels are blocked.
Optical Coherence Tomography - We use a machine to scan your eyes to make a detailed image of the retina.
Time is of the essence when it comes to BRAO. Minutes count in order to save your vision after an eye stroke. You may avoid lasting injury if we can clear the central artery blockage and restore blood flows within 90-100 minutes. But after 4 hours, the blockage could damage your vision for good.
We offer our patients the following treatments:
Eye massage - We will massage your closed eyelid with a finger to try and dislodge the clot.
Carbon dioxide-oxygen - You breathe in a mixture of carbon dioxide and oxygen to increase blood flow to the retina and widen the arteries.
Paracentesis - To reduce pressure and increase blood flow to the retina we use a small needle to remove a few drops of fluid from the front of your eye.
Medication – We may prescribe drugs to bust clots or to lower the pressure in your eyes. These include drugs used for glaucoma, like acetazolamide (Diamox).
The Annan Retina Eye Center recommends evaluations every 1 – 2 months until your vision is stable or until your vision recovers. More than 80% of patients who have BRAO will recover visual acuity of 20/40 or better, although it is common to have permanent blind spots or distortions.
Central Retina Artery Occlusion (CRAO)
Central retinal artery occlusion is a painless sudden loss of vision usually occurring in one eye and is considered a stroke of the eye. Most people who have CRAO can barely count fingers in front of their face or see light from the affected eye.
With CRAO the retina will be pale, and the vessels narrowed. If treatment is sought within the first few hours of onset, the retinal signs may not yet be present, and a fluorescein angiogram may be required to confirm the diagnosis. This procedure, which is very safe, entails injection of fluorescein intravenously with retinal photography afterward.
No treatment method has been shown conclusively to benefit CRAO. But if you are seen within 24 hours after acute vision loss begins, we may be able to dislodge the embolus. If the embolus can be dislodged, blood flow to the retina may be restored partially. Vision loss is less likely if treatment is sought within 90 minutes. However, after 90 minutes of blood flow loss the retina suffers irreversible injury. Despite all efforts to preserve vision, even when you are seen immediately, most patients suffer severe and permanent visual loss.
To learn more about Retinal Artery Occlusion treatment options please schedule a visit with Dr El Annan at the Annan Retina Eye Center. Please call 346-22A-NNAN to speak to a member of staff who will be more than happy to help you.