Cataracts in pilots: A double whammy?

Recently I wrote a piece about the health hazards that pilots face from sun exposure on the flight deck. One of the hazards I mentioned was the risk of developing cataracts, a condition in which the lens of the eye becomes opaque, leading to diminished vision. (The photo at right is a scene as it might be viewed by a person with cataract.)

Exposure to UV rays from the sun is not the only risk factor for cataracts encountered by professional pilots. Research has shown that airline pilots also are at risk for developing cataracts as a result of occupational exposure to cosmic radiation. The results of this research appear in the Archives of Ophthalmology, a specialty medical journal published by the American Medical Association.

A research team at the University of Iceland studied a sample of 445 men over the age of 50. Among the men in the sample were 79 airline pilots. The researchers performed detailed eye examinations on the men in the study. Cataracts were found in 71 of the men, including 15 of the pilots.

In addition to undergoing the eye examination, the study participants also were interviewed about previous diseases, medications, and lifestyle factors such as smoking status and sunbathing habits. This enabled the researchers to control for these additional risk factors in their analysis.

The results of the analysis showed that the pilots had roughly triple the risk for cataracts as the other men in the sample.

The authors had this to say about the results for pilots in the study:

Our calculations show a significant association between length of employment (measured in years), cumulative radiation dose (measured in millisieverts), and cumulative radiation dose sustained before the ages of 50 and 40 years and risk of nuclear cataracts, adjusted for age, smoking status, and sunbathing habits among commercial airline pilots.

The kind of cataracts found in the pilots, called 'nuclear cataracts,' are characterized by clouding that begins near the center of the lens and then spreads. Although nuclear cataracts can be age-related, the pilots appeared to be getting the cataracts at a younger age than the non-pilots in the study.

Source: Rafnsson, V., Olafsdottir, E., Hrafnkelsson, J., Sasaki, H., Arnarsson, A., & Jonasson, F. (2005, August). Cosmic radiation increases the risk of nuclear cataract in airline pilots. Archives of Ophthalmology, Vol. 123, pp. 1102-1105.

Related Information: Aircrew Exposure to Cosmic Radiation.

Photo Source: National Eye Institute, National Institutes of Health, Ref#: EDS03