Retinal occlusion stroke, often called an “eye stroke,” is a serious medical condition affecting vision. It occurs when blood flow to the retina, the light-sensitive tissue at the back of the eye, becomes blocked. This can lead to sudden vision loss. Prompt recognition and management are important for potentially preserving vision and addressing underlying health concerns.
Understanding Retinal Occlusion Stroke
A retinal occlusion stroke involves an interruption of blood supply to the retina, the nerve tissue responsible for converting light into electrical signals for vision. When retinal arteries are blocked, cells are deprived of oxygen, leading to damage and impaired vision. The extent of vision loss depends on the location and size of the blocked vessel.
There are two types of retinal artery occlusions. Central Retinal Artery Occlusion (CRAO) occurs when the main artery supplying blood to the entire retina is obstructed. This blockage results in severe, widespread vision loss across the entire visual field of the affected eye. Branch Retinal Artery Occlusion (BRAO) involves a blockage in one of the smaller arteries. In BRAO, vision loss is usually partial, affecting only a specific section of the visual field, such as peripheral vision or creating blind spots.
Recognizing the Warning Signs
The hallmark symptom of a retinal occlusion stroke is sudden, painless vision loss in one eye. This loss can manifest as blurriness, a dark curtain descending over vision, or a complete inability to see. Some individuals might also experience distorted vision or blind spots.
Symptoms can last from seconds to minutes, or they may result in permanent vision impairment. Any sudden vision changes warrant immediate medical attention. Prompt evaluation is needed to potentially mitigate vision loss and assess for broader health implications.
Causes and Risk Factors
Retinal occlusion strokes arise from a blockage within the retinal arteries, most commonly caused by an embolus (a small piece of cholesterol) or a thrombus (a blood clot). These blockages often originate from larger arteries, such as the carotid arteries in the neck, or from the heart.
Several systemic health conditions increase a person’s risk. Atherosclerosis, characterized by fatty deposits hardening the arteries, is a common underlying factor. High blood pressure (hypertension), elevated cholesterol levels, and diabetes contribute to vessel damage and raise the risk. Heart conditions, particularly atrial fibrillation, can lead to blood clots that may travel to the eye. Other less common causes include inflammatory conditions like giant cell arteritis, which can cause artery swelling, and certain blood clotting disorders.
Diagnosis and Management
Diagnosing a retinal occlusion stroke begins with a comprehensive eye examination. A dilated fundus exam allows the ophthalmologist to view the back of the eye, often revealing a “cherry-red spot” in the macula with surrounding pale retina in CRAO, indicating a lack of blood flow. In BRAO, a localized area of retinal whitening along the affected vessel may be observed.
Imaging techniques confirm the diagnosis and assess damage. Fluorescein angiography involves injecting a dye into the bloodstream to visualize blood flow in the retina, showing delayed or absent filling of the affected arteries. Optical coherence tomography (OCT), a non-invasive imaging method, provides detailed cross-sectional images of the retina, demonstrating swelling of the inner retinal layers in acute cases, which later may thin due to atrophy. OCT angiography (OCTA) can also evaluate microvascular features and blood flow.
Acute management is time-sensitive, as irreversible retinal damage can occur rapidly, potentially within 90 to 240 minutes of blood flow interruption. Interventions aimed at restoring blood flow include ocular massage to dislodge the embolus, or medications to lower intraocular pressure, such as acetazolamide. While various treatments have been explored, none have conclusively proven to predictably improve vision. Long-term management focuses on identifying and controlling the underlying systemic conditions that caused the occlusion, such as high blood pressure, diabetes, and heart disease, to reduce the risk of future occlusions in either eye or elsewhere in the body. Patients are often referred for a systemic evaluation, similar to a workup for a cerebral stroke, which may include carotid artery imaging and a cardiac evaluation.
Preventing Future Occurrences
Preventing future retinal occlusion strokes centers on the proactive management of systemic health conditions. Maintaining control over blood pressure, diabetes, and cholesterol levels through medication and lifestyle adjustments is a primary step. Adopting a healthy lifestyle, including regular physical activity and maintaining a healthy weight, contributes to vascular health.
Quitting smoking is another measure, as smoking increases the risk of vascular disease. Regular medical check-ups are important to monitor these risk factors and detect any new or worsening conditions early. These preventative strategies are generally consistent with those recommended for reducing the risk of stroke or heart disease.