A British Airways pilot suffered severe eye damage after a laser was shone into his cockpit at Heathrow airport, the British Airline Pilots' Association has said. There have been many such attacks in the last one year and the latest was with a laser of "military strength".

The pilot's right eye's retina reportedly got burned in the attack when the plane was landing at the airport, according to the association's general secretary, Jim McAuslan. The incident has raised concern over the safety of pilots.

"We're very concerned about it. When something as strong as this comes on the scene it starts to worry us," McAuslan told The Guardian, adding that lasers are easily available on the internet and elsewhere.

According to Balpa, cases of laser attacks on flight crew in the UK have been documented since the early 1990s. "Despite continuous improvements we are still seeing incidents in the UK involving lasers directed at landing aircraft and unfortunately they continue to be a threat to aviation," it said in a statement.

"Several events have resulted in aircraft flying the visual segment of an approach being illuminated with a strong laser by persons on the ground," it said, adding that various airline pilot associations worldwide have "for many years aggressively urged the authorities to address the laser problem".

The latest attack is thought to be the most serious in the UK, according to officials. A milder laser attack causes flash blindness and leaves a transient image in the visual field of the sufferer. "Laser illumination can result in minor and transient visual impairment, such as a retinal after-image remaining visible and/or camera flash-type blindness. Usually these symptoms subside after a period of time provided the individual does not look at the beam," Balpa said.