Examples of the present disclosure relate to methods for controlling a display device. In one such example, data representing a result of an eyewear detection operation is obtained. Dependent on the obtained data, a control signal is outputted to adjust a display parameter of the display device. Performing the eyewear detection operation comprises receiving image data representing a user of the display device, and processing the image data using object recognition to determine whether or not the user is wearing eyewear of a predetermined type.