Retinal artery occlusion
Retinal artery occlusion
Description, Causes and Risk Factors:
Retinal artery occlusion is a relatively uncommon eye condition that may cause severe vision loss. A retinal artery occlusion occurs when the central retinal artery or one of the arteries that branch off of it becomes blocked. This blockage is typically caused by a tiny embolus (clot) in the blood stream. The occlusion decreases the oxygen supply to the area of the retina nourished by the affected artery, causing permanent vision loss.
Thrombophilic disorders such as antiphospholipid antibody syndrome, protein S/C deficiencies, leukaemia or lymphomas.
Infectious origin - toxoplasmosis, mucormycosis, and syphilis.
Pharmacological causes - oral contraceptive pill, cocaine.
Ophthalmic causes - severely raised intraocular pressure, trauma or optic nerve drusen.
In many cases, no specific “cause” is identified. These blockages probably develop for the same reason that blood vessels become damaged in the rest of the body. Blood vessel blockages may be more common in patients with high blood pressure, glaucoma, diabetes, certain blood disorders and in smokers. It is also more common in older patients.
There are two main types of retinal artery occlusion: branch retinal artery occlusion (BRAO) and central retinal artery occlusion (CRAO).
BRAO (branch retinal artery occlusion): A BRAO is a blockage along a branch of the tree. This results in poor blood flow to a section of the retina.
CRAO (central retinal artery occlusion): A CRAO is a blockage of blood flow to the retina in the main trunk with sudden, severe vision loss throughout the visual field of one eye.
Carotid artery disease occurs in 45% of patients with CRAO. If presenting before age 30, retinal artery occlusion is more often associated with migraine, trauma, or coagulation disorders (blood disorders that cause easy clotting). In elderly patients, a disease called giant cell arteritis can cause inflammation of the central retinal artery, resulting in occlusion.
Symptoms may include:
Sudden, painless and complete loss of vision in one eye (Central artery occlusion).
Sudden, painless, partial loss of vision in one eye (Branch artery occlusion).
Transient loss of vision prior to the artery occlusion (in some cases).
Your retinal surgeon may order diagnostic test to determine the degree of damage caused by the artery occlusion. Blood flow in the affected area may be permanently reduced. In some cases, the eye may grow abnormal blood vessels. These complications of BRAO (branch retinal artery occlusion) and CRAO (central retinal artery occlusion) can be detected by combination of clinical examination and imaging tests. Fluorescein angiography (FA) evaluates blood flow in the retina with a series of photographs taken after intravenous injection of a synthetic dye which contains no iodine. Carotid studies, magnetic resonance angiogram, echocardiogram, and blood tests may be ordered to look for medical problems which may be life-threatening if untreated.
Unfortunately, there is currently no definitive way to reopen a blocked vessel in the retina. In some cases the body may be able to re-open or bypass the blockage through natural healing mechanisms, but the damage done, even with a temporary interruption in blood flow may be permanent.
Massage of the eye may be attempted to increase blood flow, decrease eye pressure, and dislodge emboli. Fluid may be taken from the front of the eye to lower eye pressure quickly. Sublingual nitroglycerin (nitroglycerin tablet placed under the tongue) has been tried with variable success.
If new vessels grow in the front of the eye, they may cause glaucoma, sometimes with pain and loss of vision. These abnormal new blood vessels can be treated with laser and injections of medicine into the eye, but these treatments do not restore vision.
In all cases, treatment of underlying medical conditions (such as diabetes or high blood pressure) is critical to prevent stroke or blood vessel blockage elsewhere in the body.
NOTE: The above information is educational purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.
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