If this is one of the first times you’ve heard that heart disease has something to do with your eyes — and vice versa — you’re not alone. People living with type 2 diabetes may not be aware that high blood sugar levels can cause damage to blood vessels throughout the body, including those around the heart and in the eyes. In fact, heart disease and diabetic macular edema (DME) are among the most serious complications of diabetes. Understanding how these two conditions are linked to diabetes is important because taking care of your eye health can also mean protecting your heart — and looking after your heart can help preserve your vision.

In this article, we’ll discuss how diabetes can damage blood vessels in both the eyes and heart, as well as the risk factors for both conditions. We’ll also look at what healthcare research has taught us and the steps you can take to lower your risk for DME and heart disease.

How Diabetes Damages Blood Vessels

Think of your body’s blood vessels as “pipes” that carry blood, oxygen, and nutrients everywhere. When you have type 2 diabetes, the amount of blood glucose (sugar) in your body stays higher than normal for longer periods of time.

Normally, your body breaks down the carbohydrates you eat into small units called glucose, which your body uses for energy. Glucose is a type of sugar that naturally circulates in your blood and provides energy for your cells. It’s safe at normal levels, but problems arise when blood sugar stays too high for extended periods of time.

However, in type 2 diabetes, glucose stays in the bloodstream for much longer than normal because the body has trouble moving it into cells, where glucose can be put to use creating energy. When glucose levels remain high for extended periods, they can start to damage the walls of the blood vessels. Over time, your blood vessels weaken and begin to leak, like worn-out pipes that have been exposed to rust for years.

The main point to keep in mind here is that blood vessel damage caused by type 2 diabetes leads to both DME and heart disease. So, what happens in your eyes can serve as a warning sign for what could also be happening in your heart.

How Blood Vessels in the Eyes Are Damaged

In the eyes, damage occurs in the tiny vessels of the retina, a light-sensitive layer at the back of your eye. When high blood glucose weakens these small vessels, also called capillaries, fluid can leak out of them and into the macula, a central part of the retina that helps you see fine details. If enough fluid leaks, the macula begins to swell. This swelling is called diabetic macular edema (DME). Initially, DME can make your vision blurry or distorted. However, if left untreated, DME can lead to permanent vision impairment. Diabetes can also contribute to other eye diseases such as diabetic retinopathy (damage to the blood vessels in the retina), cataracts (cloudy lenses of the eyes), and glaucoma (eye diseases that damage the nerve that connects the eye to the brain).

How Blood Vessels in the Heart Are Damaged

In the heart, high blood glucose causes a different kind of damage to the blood vessels. When vessels start to weaken due to high blood sugar, the body triggers a buildup of foam cells (immune cells that have swallowed up a lot of fat and especially cholesterol) along the weakened blood vessel walls. Foam cells are made up of harmful fatty substances that cause the large blood vessels surrounding the heart to become stiff, narrow, or clogged. This process, called atherosclerosis, reduces normal blood flow and raises the risk of chest pain, heart attack, or stroke.

Shared Risk Factors for DME and Heart Disease

Not only do DME and heart disease have the same root cause, but they also have the same risk factors. This means the health conditions that increase your risk for DME also increase your risk for heart disease.

Some common risk factors that worsen both DME and heart disease include:

• Hypertension (high blood pressure) — Higher pressure in your blood vessels means that they’re more likely to leak when excess blood sugar damages the vessel walls.
• High cholesterol and triglycerides — Excess fat makes blood vessels even more crowded and contributes to further vessel wall damage.
• Obesity — Excess weight causes insulin resistance and inflammation, worsening the effects of diabetes on blood vessels.
• Smoking — The nicotine in cigarettes worsens insulin resistance, causing blood sugar levels to rise even higher.
• Untreated diabetes — The longer that blood glucose levels stay high, the more damage to blood vessels throughout the body.

What Research Tells Us

Researchers have done a deep dive into just how closely DME and heart disease are connected.

A large study found that people with DME had an increased risk of heart problems and death from cardiovascular, or heart-related, causes. Even after adjusting for blood pressure, blood sugar, cholesterol levels, and other risk factors, individuals with DME still had a higher risk of heart health problems.

Another study found that people with type 2 diabetes and DME were more likely to also have some kind of cardiovascular disease, compared to those who had diabetes but no DME. The types of disease included heart attack, stroke, or heart failure.

If you have DME, you can take your diagnosis as a warning sign that the blood vessels in other areas of your body, namely your heart, may also be under stress. With this knowledge, you can manage the risk factors that could damage heart health.

What Does This Mean if You Have DME?

Having DME doesn’t necessarily mean that you will develop heart disease. However, it does mean that you have a higher risk than others. Therefore, it’s important to stay on top of your heart health.

Plaque buildup in the vessels doesn’t always show symptoms, so you may feel fine even when your heart is experiencing the effects of diabetes. Staying up to date with doctor visits can ensure you get routine tests done. These may include blood work, echocardiograms, electrocardiograms (ECGs, also known as EKGs), or other tests prescribed by your cardiologist to help monitor your heart’s condition.

Also, your DME diagnosis paints a larger picture of your overall health. Talk to your ophthalmologist (eye specialist) about how often you should have eye exams and what additional treatment options they recommend. Your eye health isn’t only about vision. It’s also a peek into the state of your whole body. With DME, your body could be under stress from diabetes in other areas as well.

Steps You Can Take To Protect Your Eyes and Heart

Type 2 diabetes may have many potential complications, which means that they can be prevented or minimized by being proactive about your healthy habits. Every small lifestyle change makes a difference, and your healthcare team can help guide you along the way. Here are some tips:

Maintain a healthy blood pressure below 130/80 millimeters of mercury (mm Hg). Also, be sure to take any prescribed heart medications regularly.

• Manage your blood sugar — Work with your doctor to keep your daily blood glucose levels within your set target. This is the most important step in slowing down the effects of diabetes.
• Lower your cholesterol — Making dietary changes and taking medications like statins can help control cholesterol levels and lessen the vessel damage caused by diabetes.
• Stay active — Just 30 minutes a day of regular movement can make a big difference in weight, blood pressure, and circulation. Walking, swimming, and biking are great low-risk options.
• Quit smoking — Not only will quitting help lessen the complications of diabetes, but it also makes a big impact on your overall health. Ask your healthcare team for resources to help you quit.
• Keep up with your appointments — Put your upcoming health checks in your calendar so you don’t miss regular eye health exams, diabetes care checkups, and heart screenings.

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