A hands-free system uses eye gaze information from an eye gaze tracking device to continuously control the rate and direction of scrollable information presented on a display in a natural manner. In accordance with the expression defining the beam current of the electron tube device, Ib<PVa32, where P represents the perveance of an electron gun and Va represents a voltage impressed upon an accelerating electrode, the electric potential of the accelerating electrode or an adjacent electrode is maintained at the highest level of all electrodes in the electron tube at all times. The invention also provides a latex tube which prophylactically isolates the dyed hair such that the dye does not spread in an undesired manner. In other embodiments, such a peripheral is provided without mouse-like functionality, and again permits reading machine-readable indicia printed in catalogs and the like.