Changes in retinal vessels may indicate increased risk for cardiovascular disease and conditions such as high blood pressure. Photo: CDC on Unsplash.
As the primary eyecare provider for most of the population, optometrists are in the unique position of being able to detect and comanage systemic disease before the person even knows anything is wrong. Based on the health of the eye, ODs can also determine if a patient is at increased risk of developing a particular condition, including one of the most common among today’s US population: cardiovascular disease. Researchers of a recent study investigated whether arteriovenous ratio (AVR) cut-off values can classify patients at risk of the condition.
The study group included 120 subjects in the analysis and gathered the following data from each: disc-centered retinal photographs, systolic blood pressure levels and retinal vessel parameters (central retinal artery and vein equivalent and AVR). Participants were then grouped into AVR categories modeled after the Atherosclerosis Risk in Communities Study, which researchers wrote “outlined the use of retinal vessel caliber measurement and reported that AVRs in the lowest quintile were 24-times more likely to develop incident stroke over a 3.5-year period compared with the uppermost quintile.” In addition, they calculated cardiovascular disease risk for each subject using two health calculators.
The results showed that systolic blood pressure was much greater in patients with an AVR value in the lowest category compared with the highest values (150.65mm Hg vs. 132.21mm Hg). Similarly, cardiovascular disease risk was significantly higher in those with the lowest AVR compared with the highest (14.3% vs. 9.9% by one calculator, 36.4% vs. 19.2% by the other), the researchers noted. The analysis also revealed a greater number of patients with hypertension in the lowest AVR range compared with the highest.
“Comparing these two groups, there is a clear difference in vessel caliber, with arterial narrowing and venular dilation being observed in the lower cut-off group,” they wrote. “Both of these vessel changes have been linked elsewhere to cardiovascular disease (reduced arterial caliber is strongly associated with raised blood pressure, and venular dilation has been associated with both the onset of diabetes mellitus and stroke). In addition, cardiovascular risk was found to be greater in the lower cut-off group.”
The two algorithms used for risk calculation are designed to estimate risk over a 10- and 30-year period, respectively. Because the lower cut-off group showed an increased risk of cardiovascular disease using both methods, the researchers suggested this implies that the group is subject to an increased risk both medium- and long-term.
This study demonstrated the potential utility of retinal vessel analyses for predicting cardiovascular disease risk in patients. More research will be needed to define its specific application for optometry clinic-based health risk assessment.
French C, Cubbidge RP, Heitmar R. The application of arterio-venous ratio (AVR) cut-off values in clinic to stratify cardiovascular risk in patients. Ophthalmic Physiol Opt. March 7, 2022. [Epub ahead of print].