How does an eye stroke happen?
Healthy retinal tissue depends on small blood vessels to deliver oxygen and nutrients. An artery can become blocked by a small clot or cholesterol-containing material travelling through the bloodstream. The material may originate from the heart, neck arteries or another blood vessel.
Inflammatory conditions can also reduce blood flow. In older adults, giant cell arteritis is especially important because it can threaten vision in the other eye and requires urgent systemic treatment. Sometimes the cause is not immediately obvious; that does not make the event harmless.
Eye stroke vs retinal vein occlusion
In a retinal artery occlusion, oxygen-rich blood cannot enter the retina. The presentation is often sudden and painless, and acute retinal artery occlusion is treated as an emergency.
In a retinal vein occlusion, blood has difficulty draining out of the retina. This can cause bleeding, leakage and swelling. The treatment differs between the two and may include eye injections, steroid treatment, laser or observation depending on the findings. Symptoms alone cannot safely distinguish the conditions, so examination and imaging are essential.
Who is more likely to have an eye stroke?
- People with high blood pressure, diabetes or high cholesterol
- People who smoke or have heart disease or an abnormal heart rhythm
- People with previous stroke, TIA or carotid artery disease
- People with blood-clotting or inflammatory disorders
- People with a history suggesting wider vascular disease
What happens at the hospital?
The medical team will establish what happened and how quickly it happened. They may ask when the change began, whether one or both eyes are affected, whether pain or headache was present and whether there is a history of diabetes, blood pressure, heart disease, high cholesterol or medicines that affect clotting.
The examination may include visual acuity, pupil assessment, eye pressure, a dilated retinal examination and imaging. If an arterial occlusion is suspected, medical or neurological evaluation may be required to find a source and reduce the risk of another vascular event.
What should you do?
If someone suddenly loses vision, note the start time, arrange emergency transport and avoid driving. Do not wait for the vision to return or schedule a routine appointment for next week. Treatment decisions must be guided by the treating ophthalmologist and, when appropriate, emergency or stroke specialists.
