A British eyeball tracking system developed for fighter pilots is due to be incorporated into commercially available sunglasses.

The Mobile Eye system uses two miniature cameras to record exactly what the eye sees, and sends the images to a belt-mounted digital recorder.

Developed by British firm Qinetiq, formerly the Defence Evaluation and Research Agency before its sale to the Carlyle Group, the system is manufactured in the US by Applied Science Laboratories.

"People can become so highly skilled at tasks that they become automatic," explained Adrian Huggins, Qinetiq's business group manager responsible for the project.

"The analysis of the related eye movements can help us understand how these tasks are effortlessly achieved. With Applied Science taking on the manufacturing of this truly portable, real-time system, so many opportunities are now possible."

Mobile Eye was originally developed as a 'Look and Fire' system for fighter pilots, but falling component costs has made it practical for civilian applications.

The commercial device will initially be used by athletes to monitor and improve performance, and by market researchers looking to see how people react to websites, retail environments or adverts.

The glasses will initially cost about $20,000 but the price is expected to fall.