A near-to-eye display (NED) device comprises a light sensor, a processor, a first imager to generate a left image of an object for the user's left optical sensor, and a second imager to generate a right image of the object for the user's right optical sensor. The device further comprises at least one light-transmissive optical component arranged to receive concurrently the left image and the right image, the at least one light-transmissive optical component further arranged to direct a first portion of each of the left and right images to the left and right optical sensors, respectively, of the user while directing a second portion of each of the left and right images to the light sensor. The at least one processor detects a binocular misalignment between the left and right images based on output of the light sensor and to control the imagers to correct for the misalignment.