This could allow people with severe mobility disabilities to play video games:
To play the game, the user wears special glasses containing an infrared light and a webcam that records the movement of one eye. The webcam is linked to a laptop where a computer program syncs the player’s eye movements to the game.[...]
One of the major benefits of the new technology is that it is inexpensive, using off-the-shelf hardware and costing approximately £25 to make. Eye movement systems that scientists currently use to study the brain and eye motion cost around £27,000, say the researchers.
You can view a video about the project at the link.