A new type of eyeglasses with electrically adjustable focus might someday render bifocals and reading glasses obsolete, the device's inventors say. So far, the researchers have made a battery-powered prototype with close-up focus that flicks on and off with a switch.
Future versions of the eyeglasses may incorporate a distance sensor to automatically adjust the focus as the viewer's gaze changes between far and near viewing, says one of the inventors, electrical engineer David L. Mathine of the University of Arizona in Tucson.
Most people by their late 40s can no longer focus on close objects. This visual defect is known as presbyopia. The company PixelOptics of Roanoke, Va., plans to create a commercial v