Scientists have long known that the eyes can provide important clues about a person’s health.
Eye doctors can sometimes spot signs of diabetes, high blood pressure, and other diseases during routine eye examinations.
Now, a new study suggests that the tiny blood vessels at the back of the eye may reveal even more about a person’s risk of heart disease and high blood pressure.
Researchers from St George’s, University of London, and several other institutions have discovered dozens of genetic factors that influence the size, shape, and structure of blood vessels in the retina.
Their findings could help scientists better understand how blood vessel health affects the heart and may eventually lead to new ways of identifying people at risk for cardiovascular disease.
The retina is a thin layer of tissue located at the back of the eye. It contains a network of tiny arteries and veins that carry blood throughout the eye. These blood vessels are unique because they can be viewed directly using a special camera without the need for surgery or invasive procedures.
Doctors have become increasingly interested in retinal blood vessels because they often reflect the condition of blood vessels throughout the rest of the body. Changes in these vessels have previously been linked to health conditions such as high blood pressure, heart disease, diabetes, obesity, and stroke.
Although these connections have been known for many years, scientists have not fully understood how a person’s genes influence the appearance of retinal blood vessels. The new study aimed to answer this question.
To carry out the research, scientists analyzed retinal images from nearly 53,000 participants in the UK Biobank, one of the world’s largest health research projects.
The UK Biobank contains detailed health information, genetic data, and medical records from hundreds of thousands of people across the United Kingdom, making it an invaluable resource for researchers.
Examining such a large number of eye images would normally take an enormous amount of time. To solve this problem, the researchers used artificial intelligence. The AI system was trained to identify arteries and veins in retinal photographs and measure their characteristics.
The technology was able to determine how wide the blood vessels were and how much they curved or twisted. Some blood vessels appeared relatively straight, while others followed more winding paths. The researchers referred to this characteristic as vascular twisting or tortuosity.
After collecting this information, the scientists compared the retinal measurements with the participants’ genetic data. They used a research technique called a genome-wide association study, often known as a GWAS. This method allows researchers to scan the entire genome of thousands of individuals to identify genetic variations linked to specific traits.
The analysis revealed 119 locations within human DNA that were associated with differences in retinal blood vessel structure. Of these, 89 genetic regions were specifically linked to the degree of twisting seen in retinal arteries.
This finding suggested that arterial twisting is strongly influenced by genetics and may represent an important biological marker of vascular health.
The researchers then explored whether these vessel characteristics were connected to blood pressure.
Their results indicated that greater twisting of retinal arteries may contribute to higher diastolic blood pressure. Diastolic pressure is the lower number in a blood pressure reading and represents the pressure inside arteries when the heart relaxes between beats.
Higher diastolic blood pressure has been associated with an increased risk of heart disease and other cardiovascular problems. The scientists believe that more twisted arteries may affect blood flow efficiency, potentially leading to changes in blood pressure over time.
The findings could have important practical applications in the future. If further studies confirm these results, retinal imaging may become a useful tool for identifying people at increased risk of cardiovascular disease before symptoms appear.
Because retinal photography is quick, safe, and non-invasive, it could potentially be used alongside traditional medical assessments to provide additional information about a person’s vascular health.
Researchers also hope that understanding the genes involved in retinal blood vessel structure may lead to new treatments that target the biological pathways affecting blood vessel health throughout the body.
The study was led by Professor Christopher Owen and colleagues and was published in the journal PLOS Genetics.
The findings add to a growing body of research showing that the eyes can provide valuable information about overall health. As technology continues to improve, a simple eye examination may one day help doctors identify hidden risks for heart disease, high blood pressure, and other serious conditions much earlier than is currently possible.
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