Writing emails, playing Pong with your eyes.

Because augmented reality glasses should probably be for those who actually need them, researches continue developing more economical solutions for suffers of debilitating strokes and spinal-cord injuries, Engadget reports. These glasses track eye movement with $35 worth of parts. 

The tracker works with two video console cameras and a pair of eyeglasses that, after calibration, can precisely track the pupils — allowing them to control a cursor or move a paddle. The researchers also figured out how to “click” the eye-mouse by winking, and can even use more precise adjustments to calculate gaze depth — meaning subjects will be able to perform more complex tasks in the future, like guide a motorized wheelchair. While by no means the first eye-tracking system we’ve seen, it’s by far the most economical. Check the video after the break to see how it works.