Stanford implant could fight glaucoma

PALO ALTO, Calif. (KGO) -- For Victoria Hernandez, regular eye exams are part of an on-going battle to save her eye sight.

Hernandez is being treated at Stanford University for glaucoma. It's a condition caused by a build-up of pressure inside the eye that can cause irreversible damage.

"I worry that I will lose my eyesight. I've had several surgeries in the right eye and two in the left," she says.

Stanford ophthalmologist Dr. Mark Blumenkranz says medications can help control glaucoma, but doctors must still track the pressure inside the eye during treatment.

"One office measurement is just a snapshot in time. We know that lots of our bodily functions vary by time of day, so we make estimates based on a single pressure measurement," he explains.

But now, a device being developed by bioengineers at Stanford could transform the way doctors monitor glaucoma. It's an implantable sensor that acts as a kind of pressure meter.

Co-developer Dr. Emre Araci says the system is built into the type of replacement lens commonly used in cataract surgery. It employs a fluid tube and stretchable membrane with a bubble of gas behind it. Using a plastic container filled with fluid. As the pressure increases, the fluid pushes against the membrane in the lens, forcing the gas forward through a channel, measuring the degree of pressure in the eye like a bar graph.

The patient doesn't actually see the sensor in their field of vision, because of the materials and placement. But they can read and even record the movements using a smartphone.

"You'll get vision enhancement and on top of it you'll be able to measure the pressure inside your eye by using a cellphone camera," Araci explains.

The system takes advantage of recent developments on smartphone optics, like another device also developed at Stanford, to allow doctors to give mobile eye exams in remote locations. While the implantable pressure-sensor must still undergo human trials, doctors believe it holds the promise of revolutionizing, and personalizing glaucoma treatment.

"If a patient sees they're pressure is high, they might administer a drop three to four times a day rather than twice a day. Or maybe we add a second drop on days the drop's not doing its job," Blumenkranz says.

And perhaps make treatment far more effective for patients like Victoria Hernandez.

"That would be amazing," she says. "To me that would relieve some of the pressure."

Written and produced by Tim Didion