Cataracts in Airline Pilots: Prevalence and Aeromedical Considerations in Japan

Introduction: Despite modern aviation being increasingly less dependent on human factors, the pilot is still part of the aircraft systems and vision is critical for flight safety. The incidence of cataract increases with age, but as most epidemiological studies focus on senior age groups, there is no data relevant to working age groups. Purpose: The aim of our study was to elucidate the prevalence of lens opacity in Japanese airline pilots. Methods: A retrospective cohort study was conducted at the Japan Aeromedical Research Center. Medical records for all ophthalmological assessments performed in the 12-mo period prior to March 2008 were reviewed. Data collected included whether there was documented lens opacity or a history of previous cataract surgery. Results: Over 12 mo, 3780 pilots underwent slit-lamp examination with an ophthalmologist as part of their scheduled medical and 105 pilots were identified with cataract. Out of these, 59/105 were bilateral, 29/105 were congenital types (of which 19 were bilateral), and 12/105 pilots gave a history of previous cataract surgery. In all 105 pilots, the visual acuity was sufficient to continue the privileges of their licenses. Conclusions: This study offers insight into the clinical iceberg of early cataracts in persons of working age. Mild and early lens opacities can cause significant glare and haze, and changes in color vision, which might compromise pilot performance even in the absence of decreased visual acuity. Cataracts in otherwise fit pilots have important aeromedical significance which requires further consideration.