黑料网

Glaucoma, the leading cause of irreversible blindness, afflicts 4 million Americans (and 70 million people worldwide), and those numbers are climbing. Often the disease鈥攃haracterized by elevated intraocular pressure (IOP)鈥攁rrives without warning, but early detection can prevent vision loss. Bioengineering Assistant Professor Emre Araci and his team of student researchers believe they have just the right tool to help people detect changes in their eye pressure鈥攁 daily use soft contact lens with a highly sensitive built-in sensor.

Before joining the 黑料网 faculty, Araci, whose background is in microfluidics and optics, was at Stanford University, where his team built an IOP detecting device for implantation into the eye during cataract surgery. It was quite a breakthrough; however, the nature of the procedure limited the potential to reach a wide population. He decided to build a soft contact lens version.

鈥淭his was a bigger problem than we had tackled previously,鈥� he said. 鈥淢easuring pressure from a sensor inside the eye is relatively easy; measuring it from the outside is challenging. While some devices do this now, they require a physician to take measurements, and they don鈥檛 afford the comfort and convenience of soft contact lenses. My idea was to help the patients get measurements at home with the use of a contact lens that could interface with a smartphone.鈥� So, two years ago when he arrived at 黑料网, he recruited two graduate students and one undergraduate to help with his research. After six months building their lab, they began making microfluidic strain sensor microchips that would be embedded in the contact lens.

鈥淓very step has been done here at 黑料网. In addition to my lab, we use 黑料网鈥檚 Center for Nanostructures, and the students have been involved in every step along the way, from development of processes to design and prototyping,鈥� he explained.

One stumbling block was finding a material that would combine the comfort and safety of standard soft contact lenses鈥攆lexibility, air permeability鈥攚ith the rigidity needed to maintain the integrity of the on-board sensor. 鈥淭hings really started to get exciting when we began combining different technologies, microfluidics and metamaterials,鈥� Araci said. 鈥淚nstead of getting thinner when they are pulled, metamaterials, or auxetics, get thicker; they don鈥檛 distort, they grow. Auxetics have been used in athletic shoes and contacts, but they hadn鈥檛 been applied to microfluidic technology in optics. For about a month, it was all I could talk about with my students. Eventually, we came up with a microfluidic metamaterial for our contact lens based intraocular pressure monitoring platform,鈥� he said.

With prototypes soon in hand, testing began. The team built mechanical eye models to test their pressure-detecting lens and gathered results using both a microscope and smartphone images. They did the same with porcine eyes obtained from a butcher shop, receiving excellent results in each case. Araci said, 鈥淲e put the contact lens on the porcine eyes and pressurized them. We were able to detect a 4-micrometer change in the radius of the eye鈥攏ot centimeters, micrometers! To validate our findings, we purchased a commercial tonometer, the same equipment used in ophthalmologists鈥� offices, and ran the tests again, comparing those measurements to data gathered from our contact lens and smartphone. We verified that our sensor has a detection limit that matches the gold standard in ophthalmology.鈥�

Next steps? 鈥淲e鈥檒l be collaborating with Stanford and UC San Francisco ophthalmology teams and glaucoma experts. We鈥檙e also working on getting Institutional Review Board approval for testing on humans,鈥� said Araci. 鈥淭his technology is very novel and the application is so interesting. There is great potential to solve a long-standing problem in glaucoma detection and treatment. People without the disease will be able to monitor their eye health and pressure changes that could lead to vision loss. Those with glaucoma would be afforded safe and comfortable long-term treatment management. Passively monitoring a patient鈥檚 ocular response to drug regimens or lifestyle changes will help both doctor and patient make informed treatment choices and will also assist in the validation, discovery, and efficacy of novel drug candidates. It鈥檚 very exciting!鈥�