Scratching your glasses usually means you've just ruined them, but an Israeli researcher has figured out a way to etch a lens so that it acts as a bifocal — letting the wearer see things both near and far — but without the hassle.
The method used by Professor Zeev Zalevsky of the Bar-Ilan University has glasses working just as well from just one foot away to anything in the distance. (Bear in mind we're not talking about binoculars here, but you'd be able to see distant details just as clearly as someone with perfect vision.)
Today, if someone with impaired vision wants the same, bifocals — which ol' Ben Franklin (pictured above) is credited with inventing — are the best bet, but the wearer constantly has to tilt their head to look through lenses for near or far viewing.
Zalevsky's method eliminates the need for embedded lenses:
It involves engraving the surface of a standard lens with a grid of 25 near-circular structures each 2 millimetres across and containing two concentric rings. The engraved rings are just a few hundred micrometres wide and a micrometre deep. "The exact number and size of the sets will change from one lens to another," depending on its size and shape, says Zalevsky.
Now, there has been a bit of criticism leveled at the glasses, which may or may not cancel out some of the light hitting one's eyes because of this pattern of interference. Zalevsky claims that this is minor, though, and that the brain compensates for it in ways that the eye can't. As we get older, our eyes gradually lose the ability to change shape in a way that's necessary for our vision to stay crisp.
Is it a revolution waiting to happen for glasses? Maybe. It sounds like there are still some kinks to work out, but with something like this on the horizon, the bifocals' days are definitely numbered.
Via New Scientist