What is Medicine – What is Central Retinal Artery Occlusion?
Central retinal artery is a branch of ophthalmic artery. Ophthalmic artery is a branch of the internal carotid artery. The central retinal artery supplies the blood to the retina.
When there is a blockage to the blood flow through the central retinal artery this will lead to the central retinal artery occlusion. The blockage is most commonly due to atherosclerosis.
Another cause is giant cell arteritis. It is a form of vasculitis affecting the ophthalmic or central retinal artery which leads to reduced blood flow. This commonly happens in white female patient age 50 years of age
The risk factors of developing retinal artery occlusion include, obesity, inactivity, older age, family history, poor diet, diabetes, hypertension, alcohol consumption and smoking.
Fundoscopy examination may reveal pale retinal with a cherry red spot. The pale retinal is due to the lack of perfusion with blood.
Patient with central retinal artery occlusion may present with symptoms and signs such as sudden painless loss of vision.
The common signs include relative afferent pupillary defect. Relative afferent pupillary defect is presented with the pupil in the affected eye constricts more when light is shone in the other eye compared to when it is shone in the affected eye.
Relative afferent pupillary defect occurs due to the input not being sensed by the ischemic retina when testing the direct light reflex but being sensed by normal retina due to consensual light reflex.
The treatment is best on referral to thean ophthalmologist for assessment and management.
In emergency scenario, the immediate management may include ocular massage, reducing intra ocular pressure by removing fluid from the anterior chamber and inhaling carbogen or sublingual isosorbide dinitrate to dilate the artery.
In case of giant cell arteritis which cause retinal artery occlusion., the test includes temporal artery biopsy and treatment with high dose of steroids.
Long term treatment include secondary prevention of cardiovascular disease or treatment of reversible risk factors.
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