Joined: 16 Mar 2004
|Posted: Thu Aug 20, 2009 3:02 pm Post subject: Contact Lenses Feel the Pressure
These contact lenses with a pattern of conductive silver wires could be used to
measure pressure inside the eye and study glaucoma, a major cause of blindness.
Each lens (pictured) consists of a transparent polymer with tiny, opaque electrical circuits (gold). The circuits exhibit changes in voltage as the lens is bent or pressed.
(Tingrui Pan/UC Davis photo)
Currently, the only way for patients with glaucoma to keep tabs on the disease is to go to the doctor's office. There, a clinician administers one of several tests to measure glaucoma's main risk factor, intraocular pressure (IOP), and prescribes medication accordingly. But such visits normally occur two or three times a year, and there's no take-home monitoring device for patients who may experience pressure spikes between visits.
Now, "Smart" contact lenses that measure pressure within the eye and dispense medication accordingly could be made possible using a new material developed by biomedical engineers at UC Davis.
Tingrui Pan, assistant professor of biomedical engineering, and postdoctoral researcher Hailin Cong started with a material called polydimethylsiloxane (PDMS). They developed a method for placing powdered silver on the PDMS in a precise pattern, to create conductive wires. The silver also has antimicrobial properties.
The researchers were able to shape the PDMS-silver into a contact-lens shape, and show that it could function as a simple pressure sensor. Glaucoma, a build-up of pressure in the eye, is a leading cause of blindness worldwide. A contact lens that could continuously measure pressure within the eye and relay the data to a computer would allow doctors to learn more about glaucoma and improve patient treatment.
The researchers plan to apply for approval to begin trials of the lenses in humans, Pan said. They are collaborating with Professor James Brandt of the Department of Ophthalmology at the UC Davis School of Medicine.
A paper describing the fabrication technique was published in the July 2008 issue of the journal Advanced Functional Materials.