Eye color is determined by the amount and type of pigments and the way in which the iris scatters light. Brown eyes have more melanin, the pigment that gives color to the skin, hair, and eyes, and also have more collagen in the front part of the iris, which scatters light differently than the thinner tissue found in blue eyes. Recent studies have suggested that there may be a link between eye color and risk of coronary artery disease (CAD). CAD occurs when the arteries that supply blood to the heart become narrowed or blocked, which can lead to heart attack or stroke. One study, published in the journal "PLoS ONE," found that individuals with blue eyes had a higher risk of CAD than those with brown eyes. This association remained even after adjusting for other known risk factors, such as age, sex, smoking, and high blood pressure. The researchers suggest that the higher risk in blue-eyed individuals may be due to differences in the way that the body processes and metabolizes lipids (fats) and glucose (sugar). Another study, published in the "American Journal of Cardiology," found that individuals with blue eyes had a higher risk of CAD, as well as a higher risk of hypertension (high blood pressure), than those with brown eyes. The study also found that individuals with green eyes had a slightly higher risk of CAD than those with brown eyes, but the difference was not statistically significant. It's important to note that these studies are observational and further research is needed to confirm the link between eye color and CAD risk. Additionally, genetics and environmental factors also play a role in CAD risk, so it is not just the eye color that determines the risk, but a combination of other factors. However, it's important to take note of this research and to be aware of other risk factors for CAD, such as high blood pressure, high cholesterol, smoking, diabetes, and obesity. If you are at a higher risk for CAD, it's important to take steps to reduce your risk, such as eating a healthy diet, getting regular exercise, maintaining a healthy weight, and not smoking. In conclusion, while there may be a link between eye color and risk of coronary artery disease, it is not the only factor that determines the risk and further research is needed to confirm the findings. But it's important to be aware of the other risk factors, and to take steps to reduce the risk of CAD through a healthy lifestyle. Dr. A. Arrazaghi. MD,FRCPC