An “eye stroke” is a serious medical event that can impact vision. It occurs when blood flow to parts of the eye, particularly the retina or optic nerve, is disrupted. Prompt medical attention is important because this condition can lead to permanent vision loss if not addressed quickly.
Defining an Eye Stroke
An eye stroke fundamentally involves an interruption of blood supply to the eye’s delicate tissues. This can occur when a blood vessel carrying oxygen and nutrients to the retina or optic nerve becomes blocked or narrowed. Without an adequate blood supply, the cells in these parts of the eye are deprived of oxygen, leading to potential damage. Similar to a brain stroke, an eye stroke affects the visual system when blood flow is interrupted. This deprivation can result in impaired vision, which can range from subtle changes to complete loss.
Types of Eye Strokes
Eye strokes manifest in several forms, depending on which blood vessels are affected. One type involves blockages in the arteries supplying the retina, known as retinal artery occlusions. These include Central Retinal Artery Occlusion (CRAO), a blockage in the main artery, which often causes sudden and severe vision loss. Another is Branch Retinal Artery Occlusion (BRAO), affecting smaller arterial branches, which may lead to partial vision loss in a specific area.
A different category comprises blockages in the veins that drain blood from the retina, called retinal vein occlusions. Central Retinal Vein Occlusion (CRVO) occurs in the main retinal vein and can cause blurred vision or more significant loss, sometimes developing gradually. Branch Retinal Vein Occlusion (BRVO) impacts smaller venous branches and is characterized by blood and fluid leaking into the retina, which can swell the macula and affect central vision.
Another form is Ischemic Optic Neuropathy, which involves reduced blood flow to the optic nerve. Anterior Ischemic Optic Neuropathy (AION) affects the front part of the optic nerve, leading to vision loss due to insufficient blood supply.
Recognizing the Warning Signs
Identifying the warning signs of an eye stroke is important for seeking timely medical care. The most common symptom is a sudden, painless loss of vision in one eye. This vision loss can vary from a slight blur or a dark area in the visual field to complete blindness. Some individuals describe the sensation as a “curtain” coming down over their vision.
Other potential indicators can include the sudden appearance of floaters, which are dark spots or squiggly lines that seem to drift across the field of vision. These symptoms are unilateral, meaning they affect only one eye.
Underlying Causes and Risk Factors
Several conditions can increase the likelihood of experiencing an eye stroke, often mirroring risk factors for other vascular events. A primary cause is the formation of blood clots, which can originate in the heart or carotid arteries and travel to the eye, or develop directly within the eye’s vessels. Atherosclerosis, a condition where arteries harden and narrow due to plaque buildup, also contributes by restricting blood flow.
Conditions that damage blood vessels throughout the body also elevate risk. High blood pressure (hypertension) can damage eye arteries, making them more susceptible to blockages. High cholesterol and diabetes are systemic factors that affect vessel health and increase vulnerability. Smoking is a significant risk factor due to its negative impact on blood vessel integrity.
Heart diseases, such as atrial fibrillation, can lead to the formation of clots that may travel to the eye. Other contributing factors include glaucoma, which can affect ocular pressure and blood flow, and certain blood clotting disorders. Age is also a consideration, with eye strokes occurring in individuals over 50.
Emergency Response and Treatment
Immediate medical attention is important if an eye stroke is suspected, as time is a factor in preserving vision. Seeking care by calling emergency services or going to the emergency room is the recommended course of action. The goal of initial treatment is to restore blood flow and minimize damage to the retina or optic nerve.
One immediate action a doctor might attempt is ocular massage, where gentle pressure is applied to the eye to try and dislodge a clot. Doctors may also consider medications to dilate blood vessels or anti-clotting drugs. For retinal vein occlusions, treatments such as anti-VEGF injections can help reduce swelling and abnormal blood vessel growth, and laser treatment may be used for certain complications.
Beyond immediate interventions, long-term management focuses on addressing the underlying risk factors to prevent recurrence. This involves managing conditions such as high blood pressure, diabetes, and high cholesterol through lifestyle adjustments and medication. Regular monitoring by an eye care specialist is also important to manage any ongoing complications and protect vision.