A portable device comprising: a display unit configured to provide a visual user interface; a sensor unit configured to detect a user's gaze and a user touch input; and a control unit configured to operate the portable device in one of a plurality of modes, characterized by a tactile feedback unit configured to provide a tactile user interface; wherein the plurality of modes include: an active mode in which the display unit and the tactile feedback unit are in an activated state and in which both the visual user interface and the tactile user interface are provided; a tactile-only mode in which the display unit is deactivated and the tactile feedback unit is kept in the activated state and in which the tactile user interface is provided and the visual user interface is not provided; and a standby mode in which the display unit is kept in an inactivated state and the tactile feedback unit is deactivated, and wherein the control unit is configured to: when the portable device is in the active mode, keep the portable device in the active mode if the user's gaze is detected by the sensor unit; when the portable device is in the active mode, switch the portable device to the tactile-only mode if the user's gaze is not detected by the sensor unit in a first time interval; and when the portable device is in the tactile-only mode, switch the portable device to the standby mode if the user touch input is not detected by the sensor unit in a second time interval. a display unit configured to provide a visual user interface; a sensor unit configured to detect a user's gaze and a user touch input; and a control unit configured to operate the portable device in one of a plurality of modes, characterized by a tactile feedback unit configured to provide a tactile user interface; wherein the plurality of modes include: an active mode in which the display unit and the tactile feedback unit are in an activated state and in which both the visual user interface and the tactile user interface are provided; a tactile-only mode in which the display unit is deactivated and the tactile feedback unit is kept in the activated state and in which the tactile user interface is provided and the visual user interface is not provided; and a standby mode in which the display unit is kept in an inactivated state and the tactile feedback unit is deactivated, an active mode in which the display unit and the tactile feedback unit are in an activated state and in which both the visual user interface and the tactile user interface are provided; a tactile-only mode in which the display unit is deactivated and the tactile feedback unit is kept in the activated state and in which the tactile user interface is provided and the visual user interface is not provided; and a standby mode in which the display unit is kept in an inactivated state and the tactile feedback unit is deactivated, and wherein the control unit is configured to: when the portable device is in the active mode, keep the portable device in the active mode if the user's gaze is detected by the sensor unit; when the portable device is in the active mode, switch the portable device to the tactile-only mode if the user's gaze is not detected by the sensor unit in a first time interval; and when the portable device is in the tactile-only mode, switch the portable device to the standby mode if the user touch input is not detected by the sensor unit in a second time interval. when the portable device is in the active mode, keep the portable device in the active mode if the user's gaze is detected by the sensor unit; when the portable device is in the active mode, switch the portable device to the tactile-only mode if the user's gaze is not detected by the sensor unit in a first time interval; and when the portable device is in the tactile-only mode, switch the portable device to the standby mode if the user touch input is not detected by the sensor unit in a second time interval.