A team of researchers from the University of Oxford (United Kingdom) has presented an innovative "microstent" that could revolutionize the treatment of glaucoma, one of the leading causes of vision loss, second only to cataracts.
Worldwide, 7.7 million people were blind or visually impaired due to glaucoma in 2020. The disease can cause irreversible damage to the optic nerve due to increased pressure within the eyeball. Current treatment options, primarily surgery to create openings in the eye or insert tubes to drain fluid, are highly invasive, carry a risk of complications, and have limited durability.
"Our deployable microstent represents a significant advance in glaucoma treatment," said Yunlan Zhang, senior author of the study published in The Innovation, Cell Press. "Current surgical implants for this type of glaucoma have been shown to have limited long-term effectiveness, as they are susceptible to failure due to fibrosis (scarring) in the eye."
The new microstent features a unique structural shape that allows it to expand once inside the eye. Measuring less than a quarter of a millimeter, the stent's tiny diameter fits over a standard hypodermic syringe needle, allowing for minimally invasive insertion. Once positioned and expanded, the microstent spans the fluid-filled space between the white of the eye and the membrane overlying it.
By supporting this space, the stent reduces excessive fluid buildup and the resulting intraocular pressure in the eye, which is responsible for the most common type of glaucoma, primary open-angle glaucoma. Initial trials in rabbits revealed that the microstents reduced eye pressure in less than a month with minimal inflammation and scarring. Furthermore, the microstent achieved greater reduction in eye pressure than a standard tubular implant.
"Our microstent is made from a durable, super-flexible nickel-titanium alloy called nitinol, known for its proven long-term safety for ocular use. Its unique material and structural properties help prevent further movement, improve durability, and ensure long-term effectiveness," explained co-senior author Professor Zhong You of the University of Oxford's Department of Engineering Sciences.
The research team used advanced modeling techniques to guide the design of the microstent and ensure its compatibility with the eye's anatomy. The device's superelastic properties allow it to adapt to changes and stretching of the eye over time without permanently deforming, improving its durability and functionality.
"This breakthrough has the potential to transform the landscape of glaucoma treatment. By offering an improved solution in the field of minimally invasive glaucoma surgery that combines mechanical innovation with biocompatibility, we hope to improve patient outcomes and quality of life," said co-senior author Dr. Jared Ching of the Department of Engineering Sciences, University of Oxford.
