Sensor in eye to monitor for glaucoma
Researchers have designed a sensor that could be placed permanently in a person’s eye to track hard-to-measure changes in eye pressure that may lead to glaucoma
The sensor would be embedded with an artificial lens during cataract surgery and would detect pressure changes instantaneously, then transmit the data wirelessly using radio frequency waves, researchers said. The researchers from the University of Washington (UW) published their research in the Journal of Micromechanics and Microengineering and filed patents on an initial prototype of the pressure-monitoring device.
“No one has ever put electronics inside the lens of the eye, so this is a little more radical,” said Karl Bohringer, a UW professor of electrical engineering. “We have shown this is possible in principle. If you can fit this sensor device into an intraocular lens implant during cataract surgery, it won’t require any further surgery for patients,” Bohringer said.
The research team wanted to find an easy way to measure eye pressure for management of glaucoma, a group of diseases that damage the eye’s optic nerve and can cause blindness. At most, patients at risk for glaucoma may only get their pressure checked several times a year, said Tueng Shen, a collaborator and UW professor of ophthalmology.
But if ophthalmologists could insert a pressure monitoring system in the eye with an artificial lens during cataract surgery that could save patients from a second surgery and essentially make their replacement lens “smarter”and more functional. The UW engineering team built a prototype that uses radio frequency for wireless power and data transfer. A thin,circular antenna spans the perimeter of the device – roughlytracing a person’s iris – and harnesses enough energy from the surrounding field to power a small pressure sensor chip.
The chip communicates with a close-by receiver about any shifts in frequency, which signify a change in pressure. Actual pressure is then calculated and those changes are tracked and recorded in real-time. The chip’s processing mechanism is actually very simple,leaving the computational heavy lifting to the nearby receiver, which could be a handheld device or possibly built into a smartphone, Bohringer said.
The team has successfully tested the sensing device embedded in the same flexible silicon material that’s used to create artificial lenses in cataract surgeries. Similar to how a person’s blood pressure varies throughout the day, eye pressure is thought to behave similarly, changing perhaps minute by minute. If the pressure in the eye is too high for the optic nerve to function, however, damage to the eye can begin, often with no pain or warning signs. This increased intraocular pressure is the main factor in glaucoma, which causes vision loss and ultimately blindness.