Could a Contact Lens Save Your Vision?

Soon contact lenses won't just correct eyesight; they could save your vision.

By applying electrically conductive, antibiotic nanosilver particles to contact lenses, researchers at the University of California, Davis, can continuously map the pressure inside a human eye while administering medication directly and painlessly into it.

The new lenses promise to advance understanding of diseases like glaucoma, the second leading cause of blindness worldwide, and could save the eyesight of millions, say the researchers.

"It would be really helpful to measure the pressure inside the eye continuously," said Tingrui Pan, a professor at the University of California, Davis, and co-author of a paper describing the lenses in Advanced Functional Materials.

Pressure inside the eye, the leading indication of glaucoma, can vary widely from day to day, even minute to minute. Currently, doctors only measure pressure every few months (depending on the patient), said James Brandt, a physician at UC Davis who is involved in the research.

"Compare that to another chronic disease like diabetes, where we can have blood sugar measurements several times a day," he added.

Right now the contact lenses, made from polydimethylsiloxane (PDMS), are a close cousin to modern-day contact lenses. They have an eight-by-eight grid nanosilver lines that provide 64 pressure points. Each point independently monitors eye pressure and relays information to a computer that records the pressure inside the eye.

Future models could have thousands of points with invisible nanosilver lines.

Medicine to lower the pressure inside the eye could also be loaded into the contact lens. A mild electrical charge, unnoticeable to the wearer, would push the medication into the eye and monitor its effect -- or lack thereof.

Putting medication directly into something that many people have to wear every day could ensure that patients are taking their medication, said Jack Cioffi, editor of the Journal of Glaucoma, who was not involved in the UC Davis research.

"Roughly one-third of all kidney transplant patients go off drugs that could save their lives in less than a year," said Cioffi. "You trust that people are taking the medication, but we would like to ensure that they are compliant, and then see if the drugs are working."

Cioffi notes that other available devices can monitor internal eye pressure, but they require implantation surgery, a risk that the new contact lenses would avoid.

"Overall, this device has good promise because it's clear, can be made into a contact lens, is bio-compatable... and would make for a non-invasive intraocular pressure measuring device," said Cioffi.

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