October 21, 2018

The Eyes Really Are Windows to Your Health How Obesity Impacts Our Retina

By Kapil G. Kapoor, MD

As we become increasingly aware of the obesity epidemic, as highlighted by this month’s Medical Update, most literature focuses on its grave impact on macrovascular disease. This typically implicates the cardiovascular and cerebrovascular circulations, highlighting the increased risk of heart attacks and strokes. While far less recognized, the microvascular circulation is also significantly impacted by obesity, and the retinal vasculature is the ideal example of this. In fact, the retinal vessels easily allow the best noninvasive snapshot of a patient’s microvascular health. Direct examination of these vessels on dilated eye exam and study of these vessels with fluorescein dye within just minutes in clinic allow for this incredible accessibility.

Retinal vascular alterations are most commonly seen in patients with diabetes or hypertension and can include wider retinal vein diameter, narrowing of arterial diameter and damage at the intersection of retinal arteries and veins, also known as arteriovenous nicking. Large studies have demonstrated that patients with metabolic syndrome or obesity consistently have retinal vascular alterations such as wider venular diameter or cotton wool spots independent of a diagnosis of hypertension or diabetes, strongly suggestive of similar pathways of impact.

In reviewing data from longitudinal studies, it is evident that retinal vascular alterations have been associated with subsequent stroke, cognitive impairment, renal dysfunction and cardiovascular mortality. These associations have been found independent of cardiovascular risk factors, underscoring the importance of retinal examination in patients with metabolic syndrome. As we better understand this data, it suggests that patients found to have retinal vascular alterations may benefit from more careful systemic evaluation to further reduce their subsequent risk for macrovascular complications.

Perhaps even more concerning is the fact that metabolic syndrome and obesity can both demonstrate other retinal vascular changes that are potentially sight threatening. This includes retinal hemorrhages, microaneurysms and hard exudates – lesions that all mimic diabetic retinopathy. Additionally, particularly in patients with an undiagnosed sleep apnea overlay, patients with metabolic syndrome or obesity can suffer a branch retinal vein occlusion that is typically associated with an acute, painless blind spot developing in their central vision, requiring several months or even years of consistent treatment. These clinical presentations are becoming all too familiar as patients with metabolic syndrome increasingly require sight-rescuing treatment, often months to years before they develop a true diagnosis of diabetes.

All of this research highlights the importance of treatment and prevention. As this month’s Medical Update illustrates, the importance of curbing the obesity epidemic by working as part of a unified healthcare team is paramount. While genetics play a strong role, poor diet and sedentary lifestyle are likely increasingly placing our patients at risk. While we engage in the care of all patients with obesity or metabolic syndrome, it is important to be vigilant about any visual symptoms they may have, even in the absence of a diagnosis of diabetes or hypertension. Vision loss due to microvascular retinal damage is typically preventable if treated promptly. As always, we continue to invite and rely on your teamwork in bridging the critical gaps in preventable vision loss in our community.

Kapil G. Kapoor, MD  is a Board certified ophthalmologist specializing in vitreoretinal surgery.   wagnerretina.com