title: Contact lenses and corrective flying spectacles in military aircrew--implications for flight safety.
abstract: BACKGROUND
  Refractive devices used by aviators need to suit the aerospace environment or their failure can have serious implications. A relatively minor visual disability can result in loss of life and aircraft. We surveyed commonly occurring problems with the different types of refractive correction worn by Royal Air Force (RAF) aircrew over the previous 12 mo. We also asked if they had experienced any flight safety incidents (FSI) relating to their refractive correction.
  
  
  METHODS
  A retrospective anonymous questionnaire survey was given to 700 active aircrew occupationally graded as requiring corrective flying spectacles (CFS) or contact lenses (CL) for flying.
  
  
  RESULTS
  63% (443) of the questionnaires were completed. CL were worn by 53% of aircrew; 71% of them used daily disposable CL. CFS were worn by the remaining 47% of aircrew, 14% of whom used multifocal lenses. Of CFS wearers, 83% reported problems including misting, moving, discomfort, and conflict with helmet-mounted devices (HMD). CL-related ocular symptoms were reported in 67% of wearers including cloudy vision, dry eye, photophobia, red eyes, excessive mucus formation, CL movement, itching, and grittiness. No CL-related FSI were reported over the previous 12 mo compared with 5% CFS-related FSI (p < 0.001). The graded performance of CL for vision, comfort, handling, convenience, and overall satisfaction was significantly higher than for CFS.
  
  
  CONCLUSIONS
  CFS are associated with problems in terms of comfort and safety. CL are well tolerated by aircrew, and deliver improved visual performance.
authors: Royal Centre for Defence Medicine, University Hospital Birmingham, Selly Oak Hospital, Birmingham, UK. amp195@yahoo.co.uk
authors: Andrew M
authors: AM
authors: Partner
authors: Robert A H
authors: RA
authors: Scott
authors: Penny
authors: P
authors: Shaw
authors: William J
authors: WJ
authors: Coker
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D000401:Aircraft / Q000145:classification; D001359:Aviation; D003261:Contact Lenses / Q000009:adverse effects / Q000706:statistics & numerical data*; D003625:Data Collection; D004869:Equipment Safety; D005139:Eyeglasses / Q000009:adverse effects / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008887:Military Medicine; D012189:Retrospective Studies; D012449:Safety; D011795:Surveys and Questionnaires; D006113:United Kingdom; D014785:Vision, Ocular / Q000502:physiology