Dry-eye-preventing contact lens is powered by its wearer's blinks
Many contact lens users end up suffering from an uncomfortable and sometimes even debilitating condition known as contact lens-induced dry eye (CLIDE). An experimental new contact lens, however, could keep that from happening … using a fairly simple design.
CLIDE typically occurs when the eye's tear fluid only flows across the front of a contact lens, not getting in behind it. As a result, the tears on the lens simply evaporate, not providing any moisture or lubrication to the part of the eye covered by the lens.
The condition is most often treated by administering "artificial tears" eyedrops, although other proposed treatments have included an electrically charged contact lens, a tear-gland-stimulating implant, a lubricant derived from molecules found in pig stomachs, and a probe that users stick up their nose to stimulate a nerve in their nasal cavity.
While all these approaches have their merits, scientists at California's Terasaki Institute for Biomedical Innovation (TIBI) set out to design something much simpler, which wouldn't require any conscious effort on the part of the user.
The result is a contact lens with a series of microchannels running through it. Each channel runs from a tear-collecting reservoir on the front of the lens, to a tear-dispensing reservoir on the underside of the lens. The channels are arranged in a circular spiraling pattern, each one taking in tears near the center of the lens, and dispensing them around the edges – the very center of the lens, where the pupil is located, is left completely clear.
Importantly, the lens' tear-transporting function is activated by nothing more than the pressure that the eyelid exerts upon it when blinking. This means that it would work as users blinked in the manner that they naturally would anyway, regardless of whether or not they were wearing contact lenses.
The device has already been tested on a rig that simulates a blinking eyelid. Trials on animals and human volunteers are now being planned.
"The inventive methods that our team has employed bring a potential solution for millions of people," said TIBI director and CEO Ali Khademhosseini. "It is the hope that we may extend our efforts to bring this solution to fruition."
A paper on the research was recently published in the journal Small.
Source: Terasaki Institute