title: Optimal correction in spectacles: intervention effects on eyestrain and musculoskeletal discomfort among postal workers.
abstract: BACKGROUND
  The static posture of postal workers when sorting mail can lead to musculoskeletal discomfort. Research has shown a connection between eyestrain and upper-body musculoskeletal discomfort in general, including postal workers. A previous study of postal workers found that most of those with eye strain were in need of a new correction in their existing spectacles.
  
  
  OBJECTIVE
  Evaluate intervention effects on eyestrain and musculoskeletal discomfort with new spectacles for postal workers.
  
  
  METHODS
  Postal workers subjectively reported eyestrain, musculoskeletal discomfort and their opinions of the visual environment via questionnaires pre- and post-intervention. After an eye examination the postal workers were divided into two groups: those who needed new spectacles and those who did not.
  
  
  RESULTS
  Those who needed new spectacles showed a higher prevalence of eyestrain and musculoskeletal discomfort pre-intervention. Post-intervention, the postal workers rated their vision better and the average eyestrain and musculoskeletal discomfort decreased for both groups. These workers also experienced a decrease in discomfort on the left (static) side of the neck while sorting mail.
  
  
  CONCLUSIONS
  An intervention providing the optimal correction reduces eyestrain and decreases musculoskeletal discomfort, especially from the neck.
authors.affiliation: Division of Ergonomics and Aerosol Technology, Department of Design Sciences, Lund University, Lund, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Hemphälä
authors.affiliation: Division of Ergonomics, School of Technology and Health, Royal Institute of Technology, KTH, Huddinge, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Nylén
authors.affiliation: Division of Ergonomics, School of Technology and Health, Royal Institute of Technology, KTH, Huddinge, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Eklund
mesh_terms: D000328:Adult; D001248:Asthenopia / Q000517:prevention & control*; D005139:Eyeglasses; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D059352:Musculoskeletal Pain / Q000517:prevention & control*; D009784:Occupational Diseases / Q000517:prevention & control*; D011177:Postal Service; D011187:Posture; D014786:Vision Disorders / Q000628:therapy
keywords: Mail; dynamic; glasses; lenses; neck; static; visual ergonomics; work posture