An eye oftentimes feels like the most underappreciated systems in the field of vascular biology. An eye is a highly vascular organ then it gets credit for and here’s why – ranging from high blood pressure or diabetes to early signs of stroke, an eye exam can tell a physician a lot about one’s health.
In a series of blog posts, I decided to highlight these key connections between the eye and the human body. This article will focus on the current knowledge linking eye and the heart.
There are quite a few similarities between the vasculature (or simply put, blood vessels) of the eye and heart. Not only are there functional and structural similarities, but the eye and heart also share many of the common risk factors. For example, risk factors like high cholesterol, high glucose, hypertension that contribute to atherosclerosis, can also lead to eye diseases like macular degeneration and retinal vein occlusions. Photo taken of the back of the eye, that clinicians refer to as a fundus image, lets ophthalmologists look at blood vessels directly (as shown in the picture) – an eye is possibly the only organ that gives one an all-access backstage pass to its performances. Researchers and clinicians, rightfully call the eye as the window to one’s heart (this could probably apply beyond just biomedical sciences!).
Changes in the small micro-vessels of the eye can be directly correlated to underlying cardiovascular disorders. In the late 1970’s, clinical researchers learned that atherosclerotic lesions in the retinal vessels were indications of coronary artery disease and this was found by simple observation of fundoscopic images of patients. It is also possible to measure vessel dynamics like tortuosity (twists and turns) and caliber (diameter) with retinal exams coupled with flicker-light. With advanced imaging techniques, researchers are also able to calculate small changes in the microcirculation by simply imaging the retinal vessels. An interesting study performed in twin children, measuring the retinal arteriole, was able to predict signs of myocardial infarction as well.
The non-invasiveness of imaging the retinal vessels can certainly be an appeal to clinicians who otherwise rely on angiography to diagnose coronary complications. The retinal vessels can be quite information rich, but one only needs to look closely.