Why healthy blood pressure is important for healthy eyes

How does hypertension affect the eyes?

Chronically high blood pressure, or hypertension, can hurt your eyes and vision if it leads to: 

• Damaged retinal blood vessels, called retinopathy 

• Fluid accumulation beneath the retina, called choroidopathy 

• Nerve damage, called optic neuropathy

These issues can cause blurry vision, bleeding in the eyes and even sight loss.

Hypertension is also linked to cataracts, high intraocular pressure, age-related macular degeneration and diabetic eye complications. 

If your eye doctor observes signs of hypertension during an eye exam, they will recommend that you see your primary care doctor for assessment. In addition to its effects on the eyes, untreated high blood pressure can have fatal consequences, including stroke, heart attack, kidney failure and dementia. 

READ MORE: What your eye doctor can tell about your heart health

What is hypertension?

Hypertension, or high blood pressure, occurs when the force of the blood flowing through the body’s blood vessels is chronically too high. This makes the arteries in the body: 

• Less elastic

• Leaky

• Narrower 

• Weaker 

High blood pressure leads to heart disease because of the reduction in oxygen and blood flow to the heart.

Hereditary and lifestyle factors both contribute to elevated blood pressure. Risk factors for hypertension include:

• Eating a high-salt diet

• Obesity or extra weight in the middle of the midsection

• Alcohol or tobacco use

• Family history of hypertension

• High stress levels

• Ethnic background (e.g., individuals with Afro-Caribbean ancestry have a higher prevalence of hypertensive retinopathy)

Symptoms of high blood pressure can occur years after it has begun to damage the body. This is why it is important to have routine physical exams and eye exams to monitor your health and check for signs of hypertension and other serious conditions. 

Hypertensive retinopathy

Hypertensive retinopathy is damage to the retina due to chronically high blood pressure. In general, the symptoms of hypertensive retinopathy are not evident until it has progressed into later stages (and hypertension has advanced to Stage 2 hypertension or above). 

These symptoms include:

• Blurry vision

• Double vision

• Dim vision

• Headaches

Chronically high blood pressure can cause physical changes to blood vessels such as narrowing, “zig-zagging,” nicking and swelling. Exudates (leaked fluids, proteins or fat deposits) and swelling around the macula can occur in severe cases. All of these signs are visible during an eye exam. 

According to the National Institutes of Health (NIH), there is growing evidence that hypertensive retinopathy can be a predictor of disease or death due to organ damage from uncontrolled blood pressure. This is a worrisome indicator as hypertensive retinopathy is found in up to 17% of non-diabetic hypertension patients. 

Hypertensive choroidopathy

Hypertensive choroidopathy (also called chorioretinopathy) is the result of fluid accumulation underneath the retina. This fluid is due to the development of leaky blood vessels in the choroid (the blood vessel layer in the wall of the eye) because of chronic hypertension. 

This condition can lead to distorted vision and retinal scarring, and it is associated with cell death in the arterioles of the choroid layer. Hypertensive choroidopathy is more commonly seen in younger people who have acute episodes of high blood pressure. 

Hypertensive optic neuropathy

Hypertensive optic neuropathy is damage to the optic nerve due to chronically high blood pressure, resulting from restricted blood flow to the optic nerve. This is the nerve that carries light signals from the retina to the brain.

In hypertensive optic neuropathy, nerve fibers of the optic nerve are damaged and can no longer transmit signals properly, leading to decreased vision, and, in severe cases, permanent vision loss.

Changes to the appearance of the optic nerve, such as swelling or surrounding exudates, can be detected during a dilated eye exam. 

Retinal vein occlusion

Hypertension is a major risk factor for a retinal vein occlusion (RVO), which is a blockage of blood veins in the retina of one eye. This can result from narrowed blood vessels, hardened arteries or a blood clot. 

Symptoms of a retinal vein occlusion are sudden or gradual vision loss, or blurry vision in one eye. While painless, symptoms can get worse over the next several hours or days. 

Recent clinical studies and analysis have found that the development of an RVO is associated with a higher risk of a heart attack and stroke. 

If you are experiencing symptoms of vision loss, it is important to see an eye doctor right away.

Retinal artery occlusion

A retinal artery occlusion (RAO) is the restriction or blockage of blood to the retina in one eye. It causes sudden, painless vision loss. The location of the blockage and whether it is a central or branch RAO determines the extent of visual impairment.

High blood pressure can increase the risk of atherosclerotic plaque accumulation, which is a risk factor for RAO. This is when cholesterol clumps along the interior of the artery’s walls narrowing arteries and reducing blood flow. In the eyes, a clot or section of the cholesterol-filled plaque can result in artery blockage.  

People with high blood pressure, high cholesterol and/or diabetes are at higher risk for central retinal artery occlusion. 

If you experience sudden vision loss, it is important to see an eye doctor right away.

Diabetic eye complications

People who have both diabetes and hypertension have increased risk of complications from these conditions. Hypertension is a major risk factor for diabetic retinopathy. Control of blood pressure has been shown in clinical studies to reduce vision loss from diabetic retinopathy. 

Diabetic retinopathy can lead to diabetic macular edema (DME) in about 7% of individuals. This is swelling of the macula caused by blood vessels leaking fluid. Because the macula is responsible for central vision, DME leads to reduced visual acuity. 

READ MORE: Valsalva retinopathy

Occipital lobe stroke

Though uncommon, a stroke in the occipital lobe region of the brain is very serious and will result in cortical blindness. Because the occipital lobe processes visual images from the retina, a stroke there means the brain will be unable to process visual images, even though the eyes are healthy and pupil response is normal.

High intraocular pressure

High blood pressure increases intraocular pressure, but only by a small amount. Although research is still ongoing, many scientists believe there may be a link between high blood pressure and glaucoma, which is often associated with high intraocular pressure (IOP). 

It is interesting to note however that low blood pressure (hypotension) has been shown to increase the risk of developing glaucoma. This is because it decreases the amount of blood flow to the optic nerve.

Age-related macular degeneration

High blood pressure can increase the risk of atherosclerosis, which some researchers have linked to age-related macular degeneration (AMD). One study found that individuals who have atherosclerosis are more likely to develop AMD. 

In 2021, a study published in Acta Ophthalmologica found a significant association between hypertension and wet AMD, the less common and more visually damaging form of the disease.

Cataracts

A number of studies have found that high blood pressure can increase the risk of all types of cataracts, a clouding of the eye’s natural lens. 

A recent clinical study looked at the association between cataracts and three common conditions: hypertension, diabetes and high cholesterol. This analysis of over 800 patients undergoing cataract surgery found that high blood pressure was the most frequent risk factor for developing cataracts. 

How do I maintain healthy blood pressure?

In addition to following the recommendations of your primary care provider, there are many lifestyle choices that can help you maintain healthy blood pressure:

• Reduce your intake of salt – A high-salt diet contributes to high blood pressure.

• Eat a nutritious diet – Eat meals that are composed of whole foods such as vegetables, fruits, beans, legumes and other lean proteins.

• Exercise – Studies show that exercising 150 minutes a week greatly improves overall health.

• Maintain a healthy weight – Stay within the recommended BMI guidelines.

• Quit smoking – Create a strategy to stop smoking.

• Limit alcohol – Limit to two drinks per day for men and one drink per day for women. 

• Stress management – Stress may be linked to increased blood pressure.

How often should I see an eye doctor if I have high blood pressure?

If you have high blood pressure, you should have a dilated eye exam at least once a year or as directed by your eye doctor. If you notice any type of vision loss or have persistent eye pain, it is important to schedule an appointment with an eye doctor as soon as possible.

Annual comprehensive eye exams help to catch high blood pressure early. In fact, an eye doctor may be the first to detect hypertension. The longer it goes untreated, the more damage hypertension can do to your body, resulting in a greater risk of vision loss and the development of other serious conditions. This is why detecting high blood pressure early is crucial. 

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Page published on Wednesday, April 27, 2022

Page updated on Wednesday, April 27, 2022

Medically reviewed on Wednesday, April 27, 2022