Ring Pair Of Glasses To Rule Them All
How they work: The lenses are hollow, with a plastic sheet stretched across it on the inside. When you twist the dial, fluid pumps in between the sheet and the lens. The fluid is clear and has a high refractive index. The more fluid that pumps in, the more the curvature of the sheet increases, making the lens more powerful.
Adlens markets these glasses for the developing world since things like opthamologists and opticians can be scarce there, but they could be useful in developed countries as well.
That's actually pretty clever. But the question remains: If you turn the knob all the way do you get x-ray vision? Just a headache? Damn. So no titty-vision is what you're saying?