title: Effect of cumulative nearwork on accommodative facility and asthenopia.
abstract: OBJECTIVE
  To investigate quantitatively in young adults the relationship between long-term cumulative nearwork, degradation of dynamic accommodative ability and the presence of asthenopic symptoms.
  
  
  METHODS
  Subjects consisted of 87 young students and office workers between 18 and 31 years of age with uncorrected visual acuity of 20/30 or better in each eye. The amounts of nearwork, dynamic accommodative facility, and level of asthenopic symptoms were measured for each subject.
  
  
  RESULTS
  Total cumulative nearwork time was negatively correlated with accommodative facility and positively correlated with the number of asthenopic symptoms. Furthermore, significant correlations were found between total nearwork time and blurred vision, and blurred vision and reduced accommodative facility. Moreover, the sub-category of "hours spent reading over the years" was found to be significantly correlated with decreased accommodative facility.
  
  
  CONCLUSIONS
  The correlations suggest a relationship between cumulative amount of nearwork, decreased accommodative facility and asthenopia.
authors.affiliation: Department of Ophthalmology, Centro Médico San Luis, San Martín de Tours 2980, (1425) Capital Federal, Argentina. rafael@ar.inter.net
authors.forename: R
authors.initials: R
authors.lastname: Iribarren
authors.forename: A
authors.initials: A
authors.lastname: Fornaciari
authors.forename: G K
authors.initials: GK
authors.lastname: Hung
mesh_terms: D000065:Accommodation, Ocular; D000293:Adolescent; D000328:Adult; D001248:Asthenopia / Q000209:etiology*; D003201:Computers; D006801:Humans; D011932:Reading; D012044:Regression Analysis; D011795:Surveys and Questionnaires; D015348:Vision, Binocular / Q000502:physiology; D014792:Visual Acuity; D014937:Work