Eye stroke: Symptoms, risk factors and treatment
Eye stroke: Symptoms, risk factors and treatment
Most of us will have heard of a stroke which is a condition whereby the blood supply to part of your brain is cut off. However, strokes don’t only happen in the brain – they can also occur in your eyes. In this case, the blockage impacts your retina. The retina is the part of your eye which receives light from the lens and sends signals to the brain to process it into a visual image. The retina is a layer of tissue which relies on a constant supply of blood in order to stay healthy and function well.
This is part one of a blog post series about eye strokes. We’re going to discuss the symptoms of eye strokes and the risk factors which make you more susceptible to experiencing an eye stroke. In part two, we will cover what treatments there are to help preserve your vision after having an eye stroke, and what the prognosis is after having had one.
What is an eye stroke?
The medical term for an eye stroke is a ‘retinal artery occlusion’. This is essentially where the retinal veins become blocked, which means that oxygen cannot circulate in the eye. There are four types of blockages which can cause eye strokes – a central retinal vein occlusion (CRVO) where the main retinal vein is blocked, and a branch retinal vein occlusion (BRVO) where a smaller branch vein is blocked. Blockages can also come in the form of blocked arteries instead of veins: central retinal artery occlusions (CRAO) and branch retinal artery occlusions (BRAO).
These blockages can cause blood and fluid to leak into the retina, leading to swelling and a loss of vision. This damage can be either temporary or permanent, resulting in a partial loss of vision or even blindness. In nearly all cases, eye strokes just affect one eye, as the blockage occurs in just one vein or artery. However, research shows that after experiencing an eye stroke in one eye, there is a 30% chance that it will occur in the other eye within the next three years.
What causes an eye stroke?
There are several causes of eye strokes including a loss of blood pressure, narrowed blood vessels, and restricted or blocked arteries and veins due to blood clots. The cause of an eye stroke isn’t always clearly defined, but factors such as high blood pressure can play a part. Essentially, when the retina’s nutrients and blood supply is cut off, damage will occur. The level of the damage depends on exactly how much has been cut off from the retina, and how much leakage from blood vessels occurs.
What are the symptoms of an eye stroke?
There are a number of symptoms of an eye stroke, such as:
- Floaters
- Eye pain
- Feeling of pressure in your eye
- Blurry vision in one eye
- Complete loss of vision in one eye
- Dark shadow in your vision
- Light sensitivity
- Decreased visual contrast
Most of these symptoms will occur gradually and worsen as they progress. It’s also important to note that you won’t necessarily experience all of these symptoms during an eye stroke so, if you notice any changes to your vision, it’s crucial that you seek medical assistance as soon as possible. The sooner you treat an eye stroke, the better the chances are of saving your vision.
What are the risk factors for an eye stroke?
Several factors make you more likely to experience an eye stroke. Your risk of experiencing one grows as you get older. Men are more likely than women to experience eye strokes, as are smokers compared to non-smokers. If you already deal with any of the following conditions, your risk of an eye stroke is also higher:
- Diabetes
- Glaucoma
- High blood pressure
- High cholesterol
- Blood disorders
- Cardiovascular disease
Any condition which affects your blood sugars, blood pressure or eye pressure can make you more susceptible to experiencing an eye stroke. While everyone should monitor their vision and any changes to it, if you currently or have previously experienced any of the above conditions, you should be especially aware of changes to your vision, as your risk is much higher.
This part one of a two part blog post series on eye strokes. In our next post, we will discuss how eye strokes can be diagnosed, what treatments there are available, and what the outlook and prognosis is for people who have suffered an eye stroke.
