While it is debatable that the eyes are the “window to the soul,” they are most definitely a snapshot of your overall health. One can think of the eye as an intersection of virtually every system in the body, a true microcosm of total human health. In fact, over 300 systemic diseases can be picked up during an eye exam.
What is so special about the eye exam? The eye is the only organ in the body where we have an unobstructed view of blood vessels, nerves, connective tissue and to some extent muscle. Unlike every other exam in medicine where you are indirectly assessing the health of the tissue, eye care professionals can directly observe these tissues in action. For example, we can literally observe red blood cells pulse through the blood vessels, detect white blood cells floating around in the eye fluid, and examine brain tissue in all its glory (the optic nerve is an extension of the brain). This affords ophthalmologists “superpower” diagnostic skills to detect systemic diseases that present in the eye.
In addition to the direct clinical observation of these tissues, we have diagnostic equipment that can image these structures with accuracy down to the submicron level. To give you a comparison with traditional radiology, the imaging we routinely use in ophthalmology is over 1000x the resolution of a typical MRI. In fact, we have some devices that can image down to the level of single cells or individual neurons. Now, the truly exciting part – we can combine these powerful imaging devices with artificial intelligence to train algorithms to detect subtle features of systemic disease that far exceeds what any human can see in the eye. In fact, we just published a neat paper deploying artificial intelligence (AI) on a smartphone to enhance clinical diagnosis.
So then, the eye exam is an essential medical diagnostic event in your life that is not just about vision. Diabetes, high blood pressure, high cholesterol, kidney disease, autoimmune disease, thyroid disease, brain tumors, lyme disease, undiagnosed melanoma, sleep apnea, and rare genetic disorders can all be detected on the eye exam. Amazingly, this is just a fraction of the systemic diseases that are picked up on eye exams every day. Recently, research out of Duke University has shown that Alzheimer’s Dementia may be detected using OCT angiography, a device that we routinely use in our retina clinics. Given the massive number of systemic diseases that manifest in the eye, Ophthalmologists are on the “speed dial” of their physician colleagues from neurology to cardiology to infectious disease.
With all of this in mind, it should not be a surprise that diseases of the gut can also be picked up in an eye exam. As a dry eye specialist, I often recognize and help diagnose gut disorders based on detecting dry eye disease and this has become a special area of interest for me. For instance, small bowel overgrowth (SBO) has been linked to ocular Demodex overgrowth and can cause dry eye, styes and ocular rosacea. Recently, we presented our research at ARVO showing that patients with a lack of microbiome biodiversity in the gut were more likely to have dry eye disease. In addition to gut dysbiosis, some classic gastrointestinal diseases such as ulcerative colitis and crohn’s disease manifest with a red eye. This red eye, however, is not just your “run of the mill” red eye – it is a red eye from a unique and serious type of inflammation in the eye called iritis (or uveitis) and identifying it can lead to a prompt referral to a GI specialist.
In conclusion, the quantitative metrics found during the eye exam could well be the guide to titrate the degree of treatment for blood cholesterol levels, blood pressure, and sugar levels with the possibilities expanding every day. In the future, the eye exam with AI and enhanced imaging and detection may become the first stop in the annual medical exam.
Dr. Fishman is a Stanford-trained MD PHD ophthalmologist with a private practice in Palo Alto. Dr. Fishman is Board-Certified from the American Board of Ophthalmology (ABO), has published over 40 Peer-reviewed Publications and has 11 U.S. Patents. Dr. Fishman’s clinical focus is to improve systemic health by improving the health of the eyes and vision. Dr. Fishman sub-specializes in dry eye disease and has a holistic approach ranging from advanced diagnostics to many non-pharmacologic treatments such as PRGF Serum Tears. Dr. Fishman is passionate about advancing ophthalmic discoveries and has several industry and investigator sponsored clinical trials in dry eye disease, ocular disease biomarkers, the gut-eye microbiome, and new ophthalmic medical devices.
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Dr. Harvey A. Fishman, MD PhD. June 2021