Adlens

These glasses may look very ugly, but the technology behind them makes up for it. The power of the lenses can be adapted manually, as explained on the Adlens website:

The operating principle of our patented liquid lens technology is simple. The lens is a hollow chamber with a thin, clear, strong plastic sheet stretched across inside.

The variable lens power comes from a clear, high refractive index fluid. The fluid is pumped into (or out of) the chamber between the plastic-like sheet and the lens. As the amount of oil increases, it pushes on the plastic sheet, changing its curvature. The more it curves, the more the lens power increases.

When the fluid is pumped back out, the lens curvature flattens, reducing the power. The base hard lens has a negative power, meaning that with little or no oil, objects are demagnified.

The product is aimed mainly at developing countries, but in my opinion, it could be very useful in the developed world as well. Having a kid with bad eye vision can be terribly expensive for parents. Take me, for example. When I was young, my parents had to buy me new lenses every 5 months or so. Lenses aren't cheap, and the old ones just get thrown away. Seems like a waste of money, no? With these liquid lenses, parents could just buy one pair of glasses and have them adjusted every few months. But if Adlens wants their product to reach a market outside of the poor developing countries, they will have to come up with a nicer design for their glasses. I can't imagine that any sane parent here would let their kids wear glasses that look unfasionable like this...

But this Rwandan kid looks pretty happy with it. :)

...Ok actually, it does look cool. In a crazy pilot sort of way.