1. A display device comprising: a photon source for emitting photons for a source image, the source comprising a plurality of pixels arranged in a surface; an intermediate optical system for direction of the emitted photons; a variable power optical system for modulating wavefront curvature of photons from the intermediate optical system; and a final optical system for directing photons from the variable power optical system into a user's eye for viewing the source image with a perception of a changing image scene; characterised in that the intermediate optical system comprises means for forming the photons into pencils, each pencil having photons from a single source pixel; the variable power optical system is positioned with respect to the intermediate optical system such that the pencils converge towards one another; the device further comprises a controller comprising means for receiving source image pixel co-ordinate data and intensity data, and data representing required perceived pixel distance, and for generating an output control signal for the variable power optical system, and an output control signal for the photon source, and the variable power optical system comprises means for dynamically altering the wavefront curvature of the pencils in response to the control signal.