An eye stroke, also known as retinal artery occlusion or retinal vein occlusion, occurs when the blood supply to the retina, the light-sensitive tissue at the back of the eye, is disrupted. This disruption can lead to sudden vision problems and long-term damage. Understanding its causes and signs is important for timely intervention.
Understanding an Eye Stroke
An eye stroke is a blockage of blood flow to the retina, the specialized tissue at the back of the eye that converts light into electrical signals. When blood supply is interrupted, the retina lacks oxygen and nutrients. Vision loss severity depends on the blockage’s location and size.
There are two primary types: retinal artery occlusion (RAO), where an artery bringing blood to the retina is blocked, similar to a brain stroke; and retinal vein occlusion (RVO), where a vein carrying blood away from the retina is obstructed. Both prevent adequate blood flow, damaging retinal tissues.
Specific Causes of Eye Strokes
Eye strokes often stem from underlying health conditions affecting blood vessels. For RAO, blockages are commonly caused by an embolus—a small blood clot or plaque fragment—that travels from elsewhere in the body and lodges in a retinal artery. These emboli often originate from the carotid arteries or heart. Atherosclerosis, heart rhythm problems like atrial fibrillation, heart valve issues, and giant cell arteritis also increase RAO risk.
For RVO, blockages typically occur due to a blood clot within the vein, or when a hardened artery presses on a nearby vein, slowing blood flow. High blood pressure is a significant risk factor, damaging and stiffening retinal arteries, which can compress adjacent veins. Other conditions increasing RVO risk include diabetes, high cholesterol, glaucoma, and blood clotting disorders. While the exact cause of RVO is not always clear, systemic health issues play a role.
Recognizing the Symptoms
The most common symptom of an eye stroke is sudden, painless vision loss in one eye, ranging from partial blurring or a dark spot to complete blindness. The affected vision area depends on the blocked blood vessel’s location. For example, a central retinal artery blockage often causes severe vision loss across the entire visual field, while a branch occlusion might result in a blind spot or peripheral vision loss.
Symptoms can appear suddenly or develop gradually. Some individuals may also notice new floaters—small spots or lines that drift in their vision. In severe RVO cases, pain or pressure inside the eye can occur if abnormal new blood vessels grow and increase eye pressure. Any sudden vision change warrants immediate medical attention, as prompt diagnosis and treatment can prevent further damage and improve outcomes.
Reducing Your Risk
Managing underlying health conditions is a primary way to lower eye stroke risk. Individuals with high blood pressure should work with healthcare providers to keep it within a healthy range through medication and lifestyle adjustments. Those with diabetes need to maintain stable blood sugar levels, as high levels can damage blood vessels. Controlling high cholesterol through diet, exercise, and sometimes medication also reduces plaque buildup in arteries.
Adopting a heart-healthy lifestyle further prevents eye strokes. This includes a balanced diet rich in fruits, vegetables, whole grains, and unsaturated fats. Regular physical activity, such as at least 2.5 hours of moderate exercise weekly, benefits cardiovascular health. Quitting smoking and limiting alcohol intake are important, as smoking damages blood vessels and increases clot risk. Regular eye examinations are also advised, especially for those with existing risk factors, to detect issues early.