An ultrathin liquid crystal layer sandwiched between layers of glass could render bifocals obsolete, say optical scientists at the University of Arizona and Georgia Institute of Technology in a recent paper in the Proceedings of the National Academy of Sciences.
“When we are young, we can look at objects at different distances—we can read, look at the computer, or drive—and our eyes compensate and focus everything to the retina,” says Arizona’s Nasser Peyghambarian. With age, the eye muscles get stiff and lose some of their responsiveness, leading many people to need eyeglasses. Nematic liquid crystals could adjust for focal length and thus correct for both near- and farsightedness, as well as for other aberrations in vision, he says.
In liquid crystals, the refractive index, which determines by how much light is bent, changes with applied voltage. The trick is to program a microelectronics chip to control the applied-voltage pattern to...
