An electronic device, the electronic device comprising: a display to display a graphical user interface to a user; the display comprising a source layer including multiple active light sources, each light source configured to produce a bundle of rays having a central ray, each central ray associated with an angle and one or more mask layers including multiple transmission control elements; an input port to receive a request for modifying the graphical user interface to compensate for a visual impairment of the user; and a processor to modify the graphical user interface to compensate for a visual impairment of the user by replicating an optical effect of one or more optical lenses by determining a control signal to control the source layer and the one or more mask layers to direct central rays from respective multiple active light sources of the source layer at respective angles to compensate for the visual impairment such that at least two of the central rays, from at least two respective active light sources, when viewed by the user, are focussed sharply by the user's eye onto a single retinal point to thereby replicate the optical effect of one or more optical lenses, characterised in that determining the control signal comprises determining the control signal for each of multiple subsets of pixels of the interface, and pixels within a predetermined distance belong to different subsets, such that partial images, each partial image represented by the pixels of one of the multiple subsets, are presented in succession so that the user perceives a single image. a display to display a graphical user interface to a user; the display comprising a source layer including multiple active light sources, each light source configured to produce a bundle of rays having a central ray, each central ray associated with an angle and one or more mask layers including multiple transmission control elements; an input port to receive a request for modifying the graphical user interface to compensate for a visual impairment of the user; and a processor to modify the graphical user interface to compensate for a visual impairment of the user by replicating an optical effect of one or more optical lenses by determining a control signal to control the source layer and the one or more mask layers to direct central rays from respective multiple active light sources of the source layer at respective angles to compensate for the visual impairment such that at least two of the central rays, from at least two respective active light sources, when viewed by the user, are focussed sharply by the user's eye onto a single retinal point to thereby replicate the optical effect of one or more optical lenses, to modify the graphical user interface to compensate for a visual impairment of the user by replicating an optical effect of one or more optical lenses by determining a control signal to control the source layer and the one or more mask layers to direct central rays from respective multiple active light sources of the source layer at respective angles to compensate for the visual impairment such that at least two of the central rays, from at least two respective active light sources, when viewed by the user, are focussed sharply by the user's eye onto a single retinal point to thereby replicate the optical effect of one or more optical lenses, determining the control signal comprises determining the control signal for each of multiple subsets of pixels of the interface, and pixels within a predetermined distance belong to different subsets, such that partial images, each partial image represented by the pixels of one of the multiple subsets, are presented in succession so that the user perceives a single image.