Provided herein in some embodiments is an apparatus including a rendered information-adjustment module configured to cooperate with a display interface to dynamically size-adjust rendered information displayed on the display screen, a distance module, a vision properties module, and a display modification module. The distance module can be configured to periodically determine a facial proximity to the display screen for the user in accordance with a periodic algorithm. The vision properties module can be configured to collect vision properties and store the vision properties in a vision record for the user. The display modification module can be configured to determine a direction and a magnitude for adjusting the rendered information to a new size. The periodic algorithm conserves the battery power by periodically invoking the one or more facial proximity sensors, which, in turn, reduces otherwise continuous battery power-draining size adjustments to the rendered information on the display screen.
