Scientists aim to create better contact lenses that maximize comfort, alleviate dry eye symptoms

Symptoms of dry eye syndrome -- dry, red, itchy, gritty, sore eyes -- are more common among contact lens wearers. But relief may be on the horizon, thanks to a group of Stanford University researchers and their work exploring the mechanical interactions between the eye surface, the cornea and contact lenses.

Ultimately, the group's goal is to create better contact lenses that maximize comfort and alleviate dry eye symptoms. When developing biomaterial-based devices that are in direct contact with cells, like contact lenses, their mechanical interaction with cells, biomaterial adhesion to cells and biocompatibility are all extremely important factors.

During the 88th Annual Meeting of The Society of Rheology, being held Feb. 12-16, in Tampa, Florida, Juho Pokki, a postdoctoral research fellow in the chemical engineering department at Stanford University will present the group's work to enable accurately quantifying cell mechanics and the adhesion between cells and the biomaterial.

"Our system, a live-cell monolayer rheometer, is built on a standard inverted microscope for cell biology," Pokki said. "It can simultaneously observe the cells and test cell mechanisms and adhesion."

Additionally, the group created an automated system to enable controllable experiments at the microscale.

Cornea cell surfaces consist of a mechanically complex, soft material which you can think of, according to Pokki, as nature's "smart material."

"[It has] properties that depend on stress-strain conditions and time," he said. "Corneal cell mechanics and cell adhesion are altered for different corneal surface conditions, such as changes caused by disease, and different contact lenses."

By measuring mechanics and cellular or bacterial adhesion-related information, the group can compare biocompatible materials that are most suitable for contact lenses or for developing new biomedical devices such as prosthetic electronic skin. To date, one of the group's key findings is that corneal surface cells, which have adapted to protect the eye surface, are mechanically complex.

"Their effective mechanical behavior is different between small and large strain conditions," Pokki said. This behavior may be caused by changes within the cells which the group plans to study in the future.

In terms of applications, Pokki said, "beyond developing better contact lenses, our system can be used to screen and find optimal contact lens solutions or eye drops for people who have dry eye symptoms. This would allow people with dry eye syndrome to use contact lenses while maintaining corneal mechanics and adhesion similar to those of users without dry eye symptoms."