Sunglass Filter Transmission and Its Operational Effect in Solar Protection for Civilian Pilots.
BACKGROUND
The ocular effects of excess solar radiation exposure are well documented. Recent evidence suggests that ocular ultraviolet radiation (UVR) exposure to professional pilots may fall outside international guideline limits unless eye protection is used. Nonprescription sunglasses should be manufactured to meet either international or national standards. The mean increase in UVR and blue light hazards at altitude has been quantified and the aim of this research was to assess the effectiveness of typical pilot sunglasses in reducing UVR and blue light hazard exposure in flight.


METHODS
A series of sunglass filter transmittance measurements were taken from personal sunglasses (N = 20) used by pilots together with a series of new sunglasses (N = 18).


RESULTS
All nonprescription sunglasses measured conformed to international standards for UVR transmittance and offered sufficient UVR protection for pilots. There was no difference between right and left lenses or between new and used sunglasses. All sunglasses offered sufficient attenuation to counter the mean increase in blue light exposure that pilots experience at altitude, although used sunglasses with scratched lenses were marginally less effective. One pair of prescription sunglasses offered insufficient UVR attenuation for some flights, but would have met requirements of international and national standards for UV-A transmittance. This was likely due to insufficient UVR blocking properties of the lens material.


CONCLUSIONS
Lenses manufactured to minimally comply with standards for UVR transmittance could result in excess UVR exposure to a pilot based on in-flight irradiance data; an additional requirement of less than 10% transmittance at 380 nm is recommended.
Adrian C
AC
Chorley
Andrey
A
Lyachev
Michael P
MP
Higlett
Marina
M
Khazova
Martin J
MJ
Benwell
Bruce J W
BJ
Evans
D000337:Aerospace Medicine; D003315:Cornea / Q000528:radiation effects; D004781:Environmental Exposure / Q000517:prevention & control; D004867:Equipment Design; D005135:Eye Protective Devices; D006801:Humans; D009784:Occupational Diseases / Q000517:prevention & control; D016273:Occupational Exposure; D011835:Radiation Protection; D014466:Ultraviolet Rays / Q000009:adverse effects*