IOP-detecting contact lens built

A refinement in the manufacturing of contact lens material has enabled scientists to build a contact lens with an integrated sensor than can detect changes in intraocular pressure (IOP), according to results published in the July 2008 issue of Advanced Functional Materials.

Tingrui Pan, PhD of the Department of Biomedical Engineering, University of California, Davis, US and team produced polydimethylsiloxane (PDMS) by adding a chemical to the liquid solution and polymerizing the material with ultraviolet (UV) light instead of casting it in moulds; adding silver to the pre-polymerized solution also enables PDMS to conduct electricity. The "new" PDMS has high electrical conductivity and photopatternability, enabling the researchers to embed conducting circuits 10 µm wide into contact lenses.

The team produced a contact lens with a sensor to detect pressure changes within the eye. These pressure changes alter the surface configuration of the eyeball, which can be measured by the sensor in the lens and transmitted via a radio frequency identification (RFID) tag.

The sensor within the prototype contact lens is opaque, but the team is currently designed a transparent version.