Retinal artery occlusion (eye stroke)

What it is

The retina needs continuous blood flow. When an artery is blocked by clot or embolus, retinal tissue loses oxygen within minutes and vision drops suddenly, usually without pain. Central retinal artery occlusion affects the whole retina; branch artery occlusion affects a sector of vision.

Amaurosis fugax — a warning sign

Amaurosis fugax is temporary monocular vision loss, often described as a curtain or grey-out lasting seconds to minutes, then recovery. It suggests emboli from carotid artery disease or heart rhythm problems. Treat it as a transient ischaemic event: emergency stroke assessment even if vision returns to normal.

Symptoms

Typical features of established artery occlusion:

• Sudden severe or complete vision loss in one eye
• Usually painless
• May follow brief prior episodes of temporary vision loss
• Sometimes associated with other stroke symptoms if brain is also affected

Causes and links

Risk factors mirror stroke: high blood pressure, diabetes, smoking, high cholesterol, atrial fibrillation, and carotid artery narrowing. Giant cell arteritis in older adults can inflame arteries supplying the eye and needs immediate steroid treatment — a different emergency with headache and jaw pain.

Treatment and urgency

Emergency eye and stroke teams assess within hours. Treatments may attempt to dislodge emboli (ocular massage, lowering eye pressure, inhaling carbon dioxide mixtures) but vision recovery is limited once retina is damaged. Essential care includes searching for stroke source, starting antiplatelet or anticoagulant therapy, and controlling vascular risk factors.