Retinal Artery Occlusion

A retinal artery occlusion is also sometimes called an “eye stroke”. It is caused by a blockage in one of the arteries that brings blood into the eye from the heart. The most common sources of clots are the heart and the carotid arteries. There are two types or retinal artery occlusion: Central retinal artery occlusion (CRAO) which involves the main artery to the eye and results in profound visual loss, and branch retinal artery occlusion (BRAO) which involves the smaller branch arteries and may result in blurred vision or a blurred spot in the side vision.

Branch Retinal Artery Occlusion

Central Retinal Artery Occlusion

Generally retinal artery occlusions affect one eye causing a painless vision loss ranging from a small area of blurring or visual field loss to complete loss of vision. It may be preceded by episodes of vision loss called amaurosis fugax, where patients report a greying of their vision that moves from the periphery towards the centre. A blood clot in the eye may be a warning sign of clots elsewhere in the body. Patients who experience a retinal artery occlusion should have a thorough cardiovascular work-up as they are at risk of other cardiovascular problems and stroke.

There are several factors or other conditions that increase risk for having retinal artery occlusions, including:

•  High blood pressure.
• Carotid artery disease.
• Cardiac valvular disease.
• Diabetes.
• History of stroke.
• High cholesterol.
• Temporal arteritis.

A diagnosis of retinal artery occlusion may involve the following tests:

• Visual assessment
• Dilated eye examination – the affected area of retina will be pale with narrowed vessels
• Fluoroscein angiogram – where dye is injected in the arm and retinal photos confirm the changes to retinal blood flow. The diagnosis is often made with the need for this test.

No treatment has been shown to conclusively benefit a central retinal artery occlusion, and unfortunately most will have permanent vision loss. Glaucoma may develop following CRAO and patients should be monitored in case treatment is required. Branch retinal artery occlusions may result in a small area of field loss while central vision remains excellent. If temporal arteritis (giant cell arteritis) is the cause of the CRAO then treatment with systemic corticosteroids is needed to prevent loss of vision in both eyes. In addition the risk factors for artery occlusions need to be treated as a clot to an artery in the eye may be a warning sign of clots elsewhere in the body including the brain.