Blood type may increase your risk of some eye disease

Are certain eye diseases linked to blood type?

There are no recent studies that have found conclusive evidence linking a person’s blood type with specific eye conditions. However, past and current research has found an association between blood types and certain health conditions that have implications for the eyes. 

The interest in finding a link between eye disease and blood type dates back many decades. One study from the 1980s suggested that there may be an association between certain eye conditions and particular blood types. The study proposed that people with blood Type A had higher risk of cataract, corneal dystrophy and esotropia. But, to date, no additional research has confirmed the result of this study.

The renewed interest in the association between disease risk and blood type may have been sparked by early reports that suggested a link between blood type and risk and severity of illness from COVID-19. The most recent consensus is that there is no clear relationship between blood type and COVID-19 risk. 

What is the research for the link between blood type and disease?

The brief history of research into blood type and disease was covered in a recent article in The Journal of the American Medical Association. It cited research from the 1970s through early 2000s that found individuals with Type O blood are more likely to contract cholera or become infected with Helicobacter pylori, a bacterium associated with stomach ulcers. Individuals with Type O blood are also less likely to contract malaria. 

These past studies have fueled ongoing research into this topic. A recently published study from Sweden garnered a great deal of interest because it confirmed that a person’s blood type may indeed play a role in the risk and severity of certain health conditions. This study examined the health data of 5.1 million Swedes in order to analyze the link between blood type and more than 1,000 diseases. 

The Swedish study reported that individuals with blood Type A were at a higher risk of blood clots. It also found that blood Type O is associated with a higher likelihood of a bleeding condition. A new cardiovascular risk uncovered by the study was that pregnant women with Type O blood or who were RhD positive were at a higher risk for complications such as high blood pressure.

These findings are particularly relevant to the eyes because of the role that cardiovascular disease plays in a number of sight-threatening complications in the eyes.

What are the four main blood types?

There are four main blood types that are identified by proteins on red blood cells. These proteins, called antigens, are markers that help the body recognize our blood as our own. Blood type is inherited from one’s parents. 

The four main blood types are:

• Type A – Has the A antigen on the surface of red blood cells

• Type B – Has the B antigen on the surface of red blood cells

• Type AB – Has both Type A and Type B antigen on the surface of red blood cells

• Type O – Has neither Type A or B antigen on the surface of red blood cells

In addition, some people have a marker called an Rh factor on their blood cells. These people are considered Rh positive. Individuals that do not have this marker are considered Rh negative. 

The most common blood type in the U.S. is Type O-positive. The least common type is AB-negative.

How do diseases linked to blood type affect the eyes?

Individuals with blood Types A and B or AB are at an increased risk of developing blood clots as compared to individuals with blood Type O according to a 2020 study. Researchers have suggested that this is because they have higher levels of blood-clotting factors and cholesterol in their blood than Type O.

Studies show that the increased risk of cardiovascular disease puts people with blood Type AB at higher risk for a stroke. Again, researchers believe that this is because Type AB blood is more likely to clot than other blood types. 

In addition to heart disease and stroke, blood vessels of the retina and optic nerve can be damaged due to cardiovascular disease. This can lead to a number of sight-threatening conditions:

Retinal artery occlusions

The most common cause of a central retinal artery occlusion is an embolism. This is a blockage of an artery and may be caused by a blood clot. It is sometimes referred to as an “eye stroke” and can result in sudden, painless vision loss and difficulty seeing.

Retinal vein occlusions

Another type of eye stroke is central or branch retinal vein occlusion. It can be the result of high blood pressure, blood clots, narrow blood vessels or stiffened arteries that compress veins at junctions where they cross each other. Sudden or gradual vision loss and blurry vision in part or all of one eye can result.

Amaurosis fugax 

One of the causes of amaurosis fugax, a temporary loss of full or partial vision in one or both eyes, is a blockage in the arteries leading to the eyes and brain. This blockage can be caused by blood clots and can lead to a stroke. The vision loss may last for seconds to 30 minutes or even longer.

Occipital lobe stroke

A stroke in the occipital lobe, where the brain processes vision, is less common than in other parts of the brain. When it does occur, symptoms of vision loss and changes to sight can vary depending on the location. 

How can I decrease the risk of cardiovascular (and eye) disease?

There are a number of lifestyle changes that you can make to decrease your risk of cardiovascular and eye disease:

1. Don’t smoke.

2. Monitor cholesterol and high blood pressure.

3. Manage diabetes if you have it.

4. Exercise for a total of at least 150 minutes a week.

5. Eat a healthy, nutritious diet rich in vegetables and fruits and low in fats.

6. Watch your weight.

7. Reduce stress.

8. Reduce alcohol

9. Maintain good sleep habits by routinely sleeping about 7 hours each night.

While there is no direct link between blood type and specific eye conditions, researchers have found an association between blood types and cardiovascular disease. By lowering your risk of cardiovascular disease and getting routine comprehensive eye exams, you can decrease your risk of eye disease, no matter your blood type. 

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Page published on Monday, April 11, 2022