Numerical model sheds light on degenerative eye condition

Human eyeballs mainly consist of a material called vitreous, a gel-like substance that fills the eyeball from the lens to the retina. Over time, a degenerative condition called vitreous liquification causes pockets of liquid to build up within the vitreous, which can lead to further health problems and cause vision loss.

Bayat et al. developed a numerical model to explore the process of vitreous liquification, specifically looking at the flow dynamics caused by saccades, the short, rapid, scanning movements of the eye.

“Researchers believe that vitreous liquefaction can be considered as the main cause of many ocular disorders such as retinal tears, retinal detachment, vitreomacular traction, macular pucker, macular hole, etc.,” said author Javad Bayat. “Better understanding of the complex flow dynamics can shed light on possible effects of this phenomenon.”

The researchers identified one of the leading causes of vitreous liquification as stress caused by the rotation of the eye. As the eye moves, particularly during saccadic motion, the interior walls of the eye apply a force to the vitreous within, inducing a mechanical stress that can degrade the gel structure.

The team conducted a comprehensive numerical investigation of partial vitreous liquefaction in a realistic eye model, which has never been done before. They analyzed the stress generated inside the vitreous cavity under different liquefaction conditions and found significant effects caused by the lens indentation.

“The results of this work could be a first step toward the investigation of the flow dynamics of partially liquefied vitreous experimentally,” said Bayat. “Also, we are planning to study drug distribution in partially liquefied vitreous gel, which has important physiological implications.”

Source: “A mechanical model of partially liquefied vitreous dynamics induced by saccadic eye movement within a real shape of vitreous cavity,” by Javad Bayat, Homayoun Emdad, and Omid Abouali, Physics of Fluids (2022). The article can be accessed at https://doi.org/10.1063/5.0079194 .