A head-mountable display (HMD) system includes at least one detector to detect a gaze direction of an eye of a user wearing the HMD, receiving circuitry to receive a user input from the user indicating a type of eye condition for the eye of the user associated with at least partial vision loss for a region of vision, a display unit to display one or more images to the user, and a processor to generate the one or more images for display to the user by the display unit in dependence upon the type of eye condition and an output of the at least one detector indicative of the detected gaze direction of the eye.