title: Influence of VDT monitor positions on discomfort and performance of users with or without bifocal lenses.
abstract: The difficulty of video display terminal users with bifocal lenses through a traditional workstation increases the complaints and risks for upper extremity cumulative trauma disorders. Furthermore, the regular and no lens users also have problems with traditionally designed workstations over prolonged periods of video display terminal use. A study was conducted on 14 subjects to investigate the effect of computer monitor location for video display terminal users with or without bifocals on subjective assessment and performance. The two monitor locations were 15 degrees and 40 degrees below horizontal eye level. The experimental task consisted of reading words from computer screens and typing them from the reverse side to the next column. Each experimental session lasted one hour. Males with bifocal lenses had less discomfort in the neck, shoulders, forearms, and wrists, less tiredness and eyestrain and higher performance with a 40 degrees angle monitor than with a 15 degrees angle monitor. A similar conclusion has been reached for females. Users with bifocal lenses had significantly higher neck discomfort and lower performance than nonbifocal users. The 40 degrees angle monitor caused less neck discomfort than the 15 degrees angle monitor did. Overall, females had less physical discomfort, less tiredness, and higher performance than males.
authors.affiliation: Department of Industrial and Manufacturing Systems Engineering, Louisiana State University, Baton Rouge, LA 70803, USA.
authors.forename: R
authors.initials: R
authors.lastname: Balci
authors.forename: F
authors.initials: F
authors.lastname: Aghazadeh
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001248:Asthenopia / Q000209:etiology* / Q000503:physiopathology*; D016288:Computer Terminals; D012090:Cumulative Trauma Disorders / Q000209:etiology* / Q000503:physiopathology*; D006804:Ergonomics; D005139:Eyeglasses / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D009333:Neck / Q000503:physiopathology*; D009784:Occupational Diseases / Q000209:etiology* / Q000503:physiopathology*; D011187:Posture; D011597:Psychomotor Performance; D012727:Sex Characteristics; D011795:Surveys and Questionnaires