Ocular exposure to occupational non-ionising radiation in professional pilots

Research evidence supports the link between long term exposure to ultraviolet (UV)
and the blue light hazard with ocular damage including cataract and macular
degeneration. Population studies to determine the prevalence of these conditions in
pilots are inconclusive. It is known that UV and blue light intensities increase with
altitude. The aim of this research was to investigate whether professional pilots are
adequately protected from UV and short wavelength light during flight.
Informed by the results of 22 semi-structured interviews, a questionnaire exploring
the eye protection habits of professional pilots was developed and completed by
2,967 participants. The results showed a wide variation in pilot use of sunglasses,
uncovered barriers preventing sunglass use and showed a high level of
dissatisfaction regarding standard aircraft sun protection systems.
In flight irradiance measurements were captured during 6 airline and 4 helicopter
flights. No measurable UVB was found. UVA exposure was highly reliant on the
transmission properties of the aircraft windshield. Further ground measurements on
15 aircraft showed the majority had windshields which transmit significant levels of
UVA into the cockpit. This can cause the ocular dose for the unprotected eye to
exceed international recommended exposure limits within ½ hour of flight. Older
aircraft generally had superior UVA blocking windshields. Although calculated
retinal exposure to blue light hazard during flight fell well within international
recommended limits, the mean radiance was 4.1 times higher at altitude. The effect
of this over a flying career remains uncertain.
Filter transmittance measurements were taken from 34 pilot sunglasses and 20 new
sunglasses typically used by pilots. All sunglasses filters measured offered
sufficient protection from UVA in flight and ensured an attenuation of the blue light
hazard to levels equivalent to those at ground level without protection.
A series of practical recommendations are made to pilots, eye care health
professionals, industry and the aviation regulators