The eyes may be the window to the soul, but they’re also home to our most dominant sense and can be harbingers of overall health and wellness. To keep them working well, they’re fed by a vast network of blood vessels that bring oxygen to the delicate tissues of the eye. However, occasionally, the flow of oxygen-rich blood to the eyes can be blocked or interrupted. When this happens, it results in a condition called eye stroke.
One of two areas of the eye are most commonly involved in eye stroke:
- The retina, which is a film at the back of the eye.
- The optic nerve, which transmits visual information from the retina to the brain for interpretation.
Barbara Horn, a doctor of optometry and president of the American Optometric Association says the term “eye stroke is used to describe several different conditions that lead to vision loss because of lack of sufficient blood flow to the eye. An eye stroke can cause sudden loss of vision.”
Though the causes of these various types of eye stroke may be different, the end result is the same: vision loss that can become permanent if it’s not appropriately addressed as soon as possible.
The most common of these conditions include:
- Retinal vein occlusion. Dr. Andrew W. Browne, clinical assistant professor of vitreoretinal diseases and surgery at the Gavin Herbert Eye Institute at the University of California, Irvine, says “RVO is the more common type of eye stroke. It involves a reduced blood flow in a vein where blood flows away from the eye. This causes all other blood vessels closely connected to the vein to become congested or backed up.”
- Retinal arterial occlusion. “RAO is less common and can be more serious, as it may be a greater harbinger for a stroke in the brain than an RVO. RAO results from a direct blockage of flow of blood entering the eye,” Browne explains.
- Ischemic optic neuropathy. Sometimes referred to as ION, this impediment of blood flow to the optic nerve is associated with giant cell arteritis, also known as temporal arteritis, a condition in which temporal arteries in the head and brain become damaged or inflamed. If blood flow is not restored, it can cause permanent damage to vision.
- Non-arteritic anterior ischemic optic neuropathy (NAION). Similar to ION, NAION also features a disruption of blood flow to the optic nerve.
Eye strokes don’t usually cause pain, but they do cause vision loss – typically in just one eye. This loss can be temporary, but can become permanent if treatment is not sought quickly.
Other symptoms may include:
- A sudden change in vision, or a change that worsens over the course of several hours or a day or two.
- Floaters drifting through your field of vision.
- Blurred or distorted vision.
- Pressure or discomfort in the eye.
Dr. Scott B. Sheren, chair of the department of ophthalmology at ProHEALTH Care in New York, says patients “will generally present with a loss of vision,” which may appear as a “going gray or black in one eye. Sometimes this loss improves within a few minutes.”
Address Symptoms Immediately
Permanent damage can occur in just a few minutes. Even if your vision returns quickly, it’s critical to visit with your doctor ASAP – don’t wait a week. Sudden loss of vision should send you to the emergency room or the eye doctor immediately.
“Eye strokes can result in immediate decrease in vision, which may or may not be permanent. There are other complications that can occur after having an eye stroke, and this is why it is important to see an eye doctor immediately,” Browne says.
However, the American Heart Association reports that “most patients who suffer a stroke in the eye don’t get a follow-up evaluation that could help prevent them from later having a traditional – and potentially far more debilitating – stroke in the brain.”
This is why it’s so important to seek help immediately if you’ve had an eye stroke or think you may have experienced one. “Usually people with eye strokes see a retina specialist,” Browne says, but if you experience a “very rapid (acute) loss of vision in one or both eyes, you should go immediately to the emergency room.”
Diagnosis and Treatment
To diagnose an eye stroke, your doctor will “review your medical history and ask about cardiovascular disease or other conditions you may have, such as diabetes or high blood pressure. Your central visual acuity and visual field will be evaluated, and your eyes will usually be dilated to examine your optic nerve and retina,” Horn says. “Your doctor will also examine your optic nerve to check for pale color or possibly optic disc swelling,” both of which can be associated with eye stroke.
Over time, the retina can also thin and become mottled with pigment. Blood vessels in the eye may show additional signs of the stroke for a week to a month afterward. Still, it’s important to get checked out as soon as possible.
Browne adds your ophthalmologist may take “sophisticated photographs that highlight the blood flow in the eye” when examining you.
An eye stroke can be treated with medication that dissolves a blood clot if that’s the source of the impeded blood flow. Sheren says lowering pressure in the eye can sometimes help “make the clot move along if the circulation is still occluded.” This may be accomplished by inserting a needle into the eye and withdrawing fluid to bring down the pressure. Breathing into a paper bag – which increases the level of carbon dioxide in the blood – can also help reduce pressure in the eye, Sheren says. People who’ve had eye strokes often have other cardiovascular issues, so many need to take medications, such as blood thinners, to prevent future clots.
How They’re Different From Brain Strokes
Eye strokes are related to but different from cerebral or brain strokes – the so-called normal strokes we think of when someone says stroke. Eye strokes are similar in that they result from reduced blood flow, Browne explains. In addition, cerebral strokes “can also result from rupture and bleeding from an artery.”
But there is a connection between cerebral and eye strokes, Sheren adds. “The circulation to the retina in the eye is the same circulation as the front of the brain.” They’re also connected in that “strokes in the eye are a risk factor for a person having a regular stroke. They have very similar risk factors, such as high blood pressure, cardiovascular disease and age, among others,” Browne says.