The short range of the induction-loop antenna in the lens means the external antenna has to be very close to the eye: taped around the eye socket, in fact.

Lead author Eiluned Pearce said: "We found a positive relationship between absolute latitude and both eye socket size and cranial capacity."

He had a black patch over his right eye socket, a prosthetic left arm and a deformed right hand, the result of injuries from an explosives mishap during an old operation against the Soviets in Kabul.