The enterprising mind of 17 year old Luis Cruz has built a low cost, eye-controlled Human-Computer Interface (HCI). Eye controlled devices are available for around $10,000, making the technology much too expensive. This version, which you can fund via Kickstarter, is just $300 which makes it far more affordable.
An inexpensive pair of glasses houses electrodes which measure tiny electrical signals generated by the eyes. These signals are then converted into horizontal and vertical movements, allowing the user to select letters on a screen. Check out full project instructions and donate to the Kickstarter.