Although contact lenses may be less awkward than glasses, they do have their drawbacks – among these is the fact that they can cause "dry eye syndrome." Help could be on the way, however, in the form of a self-moisturizing contact.
When worn for long periods of time, traditional contact lenses can dry out the eyes by both reducing how often the wearer blinks (blinking serves to draw a fresh tear film across the surface of the eye) and increasing moisture evaporation. Corneal wounds, inflammation and discomfort may occur as a result.
Led by Prof. Matsuhiko Nishizawa, a team from Japan's Tohoku University set out to design a lens that addresses the problem.
The prototype device maintains a layer of tear fluid between itself and the eye via a phenomenon known as electroosmotic flow (EOF), in which liquid is made to flow by applying a voltage across a charged surface. In the case of the contact, a current is applied to the hydrogel of which the lens is made, drawing fluid up from the natural tear reservoir located behind the lower eyelid.
![A diagram of the self-moisturizing contact lens](https://assets.newatlas.com/dims4/default/47373b1/2147483647/strip/true/crop/600x370+0+0/resize/600x370!/quality/90/?url=http%3A%2F%2Fnewatlas-brightspot.s3.amazonaws.com%2Fbf%2Fee%2Fc1672dc94f0ba07a23797cbea790%2F20200121-research-contactlens-pic1.jpg)
So far, the scientists have successfully powered the lens utilizing built-in magnesium-oxygen and enzymatic fructose-oxygen "biobatteries." That said, they are looking into the possibility of wirelessly powering a future version of the device – they also hope to make the lens tougher, and to reduce the required voltage.
"This is the first demonstration that EOF in a soft contact lens can keep the lens moist," says Nishizawa. "In the future, there is scope to expand this technology for other applications, such as drug delivery."
A paper on the research was recently published in the journal Advanced Materials Technologies.
Source: Tohoku University