Seeing Heart Health Clearly: The Retina’s Role in Detecting Disease
February is American Heart Month. With cardiovascular disease being the number one
cause of death in the United States, there is a great need to work towards prevention.
Did you know that your eye health plays a role in identifying cardiovascular diseases
and other metabolic conditions? According to a recent study in Nature, research shows a link between tiny blood vessels in the retina and heart
disease and aging.
Denise Inman, Ph.D., Interim Chair and Professor of Pharmaceutical Sciences and NTERI Faculty at UNT Health Fort Worth, recently discussed how metabolic health appears in the eyes and its connection to heart health.
When people think about metabolism, they usually think about things like blood sugar or cholesterol. How does metabolic health show up in the eyes — and what does it have to do with the heart?
When metabolism is unhealthy — for example, with high blood sugar, high blood pressure, high cholesterol, or obesity — it damages the small vessels that supply tissues with oxygen and nutrients.
In the eye, those same risk factors can cause retinal vessels to change; they can become narrower or more dilated, stiffer, more twisted, or less branched. Vessels can become leaky, allowing blood products to enter the retina, which causes swelling. These kinds of changes mirror what is happening in the small vessels of the heart and brain, which is why the eye can act as a “window” into overall cardiovascular and metabolic health.
This study links tiny blood vessels in the retina to heart disease and aging. Why is the retina such a powerful place to see what’s happening metabolically in the body?
The retina is the only place in the body where doctors can see blood vessels and nerve tissue directly and non‑invasively, just by looking into the eye. Retinal vessels are part of the same microcirculation that runs through the heart, brain, and kidneys, so changes in their width, branching pattern, and density closely mirror risks like coronary artery disease, stroke, hypertension and diabetes. Recent work using measures of “vascular complexity” shows that simpler, less branched retinal vessels are linked to higher cardiovascular risk and faster biological aging.
The study talks about “inflammaging,” or chronic inflammation, as we get older. What does metabolism have to do with that — and how does it affect both eye health and heart health?
As we age, many people develop chronic inflammation called “inflammaging” — a slow, low-grade immune activation driven in part by metabolic stress, excess fat, and oxidative damage. Unhealthy metabolism (for example, insulin resistance as seen in Type-2 diabetics, abnormal lipids, or visceral fat) helps fuel this chronic inflammation, which in turn injures blood vessel walls, promotes atherosclerosis, and accelerates tissue aging in both the eye and the heart. In the retina, inflammaging is linked with reduced vessel branching complexity and microvascular loss, while in the heart, it contributes to stiff arteries, coronary plaque buildup, and heart failure.
Some of the key players in the study are inflammatory proteins. Can you help us understand how these kinds of molecules tie metabolism, blood vessels, and aging together?
Inflammatory proteins and enzymes connect metabolic stress to blood vessel injury and age‑related disease. A recent genetic study identified higher levels of specific proteins like MMP12 (a matrix‑degrading enzyme) and IgG–Fc receptor IIb (an immune receptor) as key links between simple retinal vessel branching and greater cardiovascular risk and shorter lifespan. These proteins sit at the crossroads of inflammation, tissue remodeling, and vascular health, driving how metabolic problems age the eye and heart microvasculature.
We often hear that conditions like diabetes or obesity affect the heart. How early do those metabolic changes start to show up in the small blood vessels of the eye?
Microvascular damage from diabetes, obesity, and metabolic syndrome can appear in the eye years before a person notices any change in their vision. In diabetes, signs like tiny hemorrhages, microaneurysms, and changes in vessel caliber are early markers of damage to small vessels throughout the body. Even in people who are overweight or have metabolic syndrome but are not yet diabetic, imaging studies show changes in retinal layer thickness and vessel patterns associated with higher body mass index and abnormal metabolic markers.
Could changes in retinal blood vessels be an early warning sign that someone’s metabolism isn’t as healthy as it should be — even before they have obvious symptoms?
Because retinal imaging is non‑invasive and highly sensitive, changes in retinal blood vessels can serve as an early warning that a person’s metabolism and vascular system are under stress. Retinal vessel width, tortuosity, branching complexity, and how old the retina looks compared with actual age are associated with metabolic syndrome, hypertension, obesity, and higher risks of cardiovascular events, even in people who appear healthy. Routine eye (fundus) photographs or OCT scans might help identify individuals whose metabolic health is poor before traditional tests or symptoms make that obvious.
This research uses genetics to tease apart cause and effect. Why is that important when we’re talking about metabolism and long-term disease risk?
Studies show that people with certain retinal changes often have heart disease or poor metabolic health, but they cannot establish cause and effect. Genetic approaches can use inherited DNA variants to test whether things like reduced retinal vessel complexity, thinner retinal layers, or higher levels of inflammatory proteins are contributing to cardiovascular disease or are simply coincident. If specific changes are contributors, then we have identified targets for therapeutic intervention.
From your perspective as an eye researcher, what’s most exciting about using genetic tools to understand the eye–heart connection?
For an eye researcher, it's exciting that large‑scale genetic and imaging datasets are turning the retina into a usable record of systemic vascular and metabolic health. Genetic tools let scientists link specific retinal traits (like vessel branching or retinal layer thickness) to both molecular pathways and clinical outcomes, revealing shared mechanisms between eye disease and heart disease that will open the door to using retinal photographs and a person’s genetic profile to identify who is at higher risk for cardiovascular problems, so prevention strategies can be employed early.
For someone reading this who’s focused on staying metabolically healthy, what’s the key takeaway when it comes to protecting their eyes and their heart at the same time?
For someone trying to stay metabolically healthy, the most important message is that what’s good for the heart is also good for the eyes. Keeping blood pressure, blood sugar, cholesterol, and body weight in a healthy range, staying active, not smoking, and eating a diet of whole foods all help preserve both retinal microvessels and coronary vessels. Eye exams, especially if you have risk factors like diabetes, hypertension, or a strong family history of heart disease, can provide important surveillance for vascular and metabolic changes.
How might this research change the way eye doctors and heart doctors think about working together?
Retinal findings could become part of how we understand cardiovascular risk and decide who needs intensive prevention or monitoring. In the future, eye doctors might routinely share concerning retinal microvascular signs with primary care and heart specialists, prompting evaluation for metabolic syndrome and cardiovascular disease. Similarly, cardiologists may view retinal imaging as a non‑invasive tool to monitor how well treatments for blood pressure, lipids, or diabetes are protecting the microcirculation, not just in the eye but throughout the body.
For more information on NTERI, please visit our website to learn more about eye health and research.