A First Look at How Diabetes Affects Retinal Arteries

As a highly vascular feature of the posterior of the human eye, the retina is especially vulnerable to problems caused by diabetes, including arteriolar narrowing, arteriovenous nicking, and retinal tortuosity, also characterized by distortion of arteries. But until now, little has been known about how exactly diabetes affects artery shape and impacts blood flow in the retina.

Using particle streak velocimetry and a blood-mimicking fluid, Tripathy et al. studied the complex relationship between hemodynamics and arterial structural changes. After extracting healthy and diabetic arteries from images, the team scaled and 3D-printed them for experimentation.

“In addition to numerical simulations, we used a high-speed camera to track particle movement and MATLAB analysis to estimate parameters like axial blood flow velocity and wall shear stress (WSS),” said author Ajay Bhandari. “Our findings show significant hemodynamic changes due to diabetes-induced morphological alterations of the artery.”

The researchers found that diabetic arteries experience as much as 10% reduction in axial blood flow velocity compared to healthy ones, contributing to atherosclerosis. They also revealed that a 14% diameter reduction in diabetic arteries causes a 65% increase in axial velocity and a 63% rise in WSS, potentially contributing to arterial wall rupture.

When the scientists exchanged the blood-mimicking fluid to less viscous water, they noted a WSS reduction of almost fourfold, supporting the use of blood thinners as an effective treatment.

“These findings could guide ophthalmologists to pay extra attention to tortuous and narrowed areas in diabetic patients,” said Bhandari. “This may aid in the early detection of issues like microaneurysms and in prioritizing patient care.”

Source: “Delineating the effects of morphological changes on retinal hemodynamics in diabetic human retinas: An invitro investigation,” by Kartika Chandra Tripathy, Md Sirajullah, Deepak Kumar Mandal, and Ajay Bhandari, Physics of Fluids (2024). The article can be accessed at http://doi.org/10.1063/5.0176806 .

This paper is part of the “Flow and the Eye” collection, learn more here .