Scientists from Japan’s Tohoku University have created a battery-driven self-moisturising contact lens to combat dry eye symptoms associated with daily contact lens wear.
The system uses electro-osmotic flow (EOF), causing liquid to flow when a voltage is applied across a charged surface. The current is applied to a hydrogel lens causing fluid to flow upwards from the patient's temporary tear reservoir behind the lower eyelid to the surface of the eye.
This automatic moisturising process makes blinking redundant and can continue for as long as there is current across the lens. The batteries used in this early prototype are tiny biocompatible batteries (Mg/O2 battery and fructose/O2 enzymatic battery). Using different lens compositions, researchers can create different charge densities which, in turn, dictate tear flow rates.
Professor Matsuhiko Nishizawa of Tohoku University said further research is required to develop tougher contact lenses capable of operating at lower currents, as well as extending the technology for other applications such as drug delivery.
