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.