Abstract
Purpose: :
Illumination of civilian aircrew with visible lasers is an increasing problem. According to the FAA, from January to Nov 2010, there have been 2,555 reports of these types of incidents, usually at night. Even low power lasers can produce intense glare that can create a flight hazard by disrupting crew performance. One way to protect aircrew from glare is to wear laser eye protection (LEP). However, the selective light filtering by LEP can alter the color and visibility of objects in and out of the cockpit, such as displays and runway lighting. We evaluated the effects of different LEP that blocked green laser light for visual compatibility with flight operations and for their impact on flight performance during laser illumination.
Methods: :
Nine pilots performed takeoff and landing maneuvers under night conditions in a flight simulator with and without green (532 nm) laser glare (6 and 60 µW·cm-²) and with and without LEP. Three of the LEP were in spectacle format and one was in a moveable shield located between the pilot and windscreen. Subjective questionnaires were used to assess the effects of LEP.
Results: :
Subjects noted significant changes in color appearance of cockpit stimuli, in particular color shifts for white, but overall reported only mild levels of difficulty (< 2 out of 10) with their instrument displays. One LEP was rated worse on 14 of 15 items (p<.001). Laser glare had significant adverse effects on flight performance and vision that increased as irradiance increased. With 60 µW·cm-² glare, difficulty ratings for seeing the runway during takeoff and landing increased from near zero to 7.3 and 5.9 out of 10. With LEP, glare was reduced, as were difficulty ratings. This amount varied among LEP, but the best filter difficulty ratings declined to between 1 and 2. In the no laser condition difficulty seeing varied with LEP and ranged between 1 and 3.
Conclusions: :
Low levels of laser glare have an adverse effect on pilot performance during critical phases of flight. Wearing LEP significantly reduces these effects. LEP are available that effectively mitigate glare without significant compromise of vision when glare is not present.
Keywords: radiation damage: light/UV • spectacle lens • scene perception