May 31, 2012, 10:23 AM — A British company called Eyejusters has released a set of glasses designed to fix the focus problems of people whose vision deteriorates over time, who need one power of magnification for long distance and another up close or simply those who want more magnification temporarily for some detail work.
The glasses from Eyejusters come with a dial on the side wearers can use to increase or decrease the magnification at will.
The lenses use a technology called SlideLens that replaces single lenses with dual. Each lens is actually a pair of magnifiers with a slightly different shape and an adjustment mechanism that changes the point of focus in the same way binoculars and camera lenses do.
The frames are also adjustable so they can fit more than the usual narrow range of face sizes addressed by normal glasses.
The glasses are designed to be cheap, adaptable and easily distributable in poor or undeveloped countries, where custom-cut prescription lenses are prohibitively expensive and far too raree.
The noble purpose and hideous styling will set Eyejusters apart from other attempts to solve the same problem, most of which are both more technically elegant and more fashionable.
Oxford University physicist Joshua Silver started manufacturing glasses with similar capabilities for similar reasons in 2009, using water-filled lenses as the adjustment mechanism rather than changing the proximity of the lenses themselves.
Last Fall a company called PixelOptics introduced last fall a set of specs that use electro-optical liquid crystals and electronic controls to change the focus of glasses and then turn off the adjuster to keep the adjustments from shifting.
Another company called SuperFocus has been selling adjustable glasses using lenses that can be snapped in or out of the eyeglass frame rather than simply sliding back and forth.
For more than a decade, researchers have also been investigating various ways to change the focus of lenses, both for eyeglasses and for optical devices such as cameras, telescopes and spy satellites.