Abstract: Devices providing adjustable optical power have previously been proposed for use as corrective lenses in prescription eyeglasses. There is disclosed a lens having optical power adjustable by relative lateral translation of two lens elements, the lens comprising: a first lens element sealed to a cover to define a cavity therebetween; a second lens element disposed within the cavity and coupled to an elongate drive element extending laterally from the second lens element, the second lens element being arranged to be driven laterally relative to the first lens element by lateral translation of the elongate drive element to thereby adjust the optical power of the lens, the lens comprising a lateral projection into which the cavity and drive element extend, the lateral projection having there mounted an adjuster for driving lateral translation of the elongate drive element. The lens reduces or prevents the ingress of dirt, moisture, sweat and grease between surfaces of the lens elements.

Abstract: A method of making a lens having adjustable optical power is disclosed. The lens is adjustable by relative lateral translation of at least two lens elements. The method may comprise providing a function yielding optical properties of the lens from starting geometries for the lens elements; refining the function to approximate required gaze angle optical performance over a range of said lateral translation; and using the refined function to derive geometries for making the lens elements. The function may comprise first and second functional parts respectively for the lens elements, and the method comprises using the function to derive geometries for making the lens elements, wherein the function relates optical path difference to a position across the lens elements, and the rate of change of curvature of the first functional part with position is different to the rate of change of curvature of the second functional part with position. There is also disclosed a lens having adjustable optical power.