Adaptive lens with the capability of changing the focusing power has important applications in 3D imaging, optical information processing, and ophthalmology. We demonstrate a switchable electroactive lens with very high diffraction efficiencies using a circular array of electrode pattern filled with liquid crystal as the active medium to be used as an adaptive eyewear. Electrically adjustable lens allows the focal length to be voltage controlled without bulky and inefficient mechanical movement. Binary Fresnel zone plates using liquid crystal as active material have been demonstrated for imaging applications, but the diffraction efficiency is low. The lens is flat and the thickness of the liquid crystal is 5 mu m. Diffraction efficiencies exceeding 90% has been achieved for an 8-level diffractive lens. The lens can be operated as both positive and negative lens. Design, modeling, fabrication, and characterization of the lens is presented. Using nematic liquid crystal, the lens is polarization dependent and two crossed lenses are integrated to form a complete lens. The ON- and OFF-state of the electrically controlled lens allow near- and distance-vision respectively for presbyopia eyes.